potential applications in highway laol ,

T L k P laol Potential Applications in Highway i ,<Pi c L , , &

Products of Rubber/Plastics Blends Based on Waste Materials

~ T:ans.oortation

Ontario

Ministry of Transportation

Research and Development Branch

Documentation Page MAT-92-1 1

Potential Applications in Highway Products of Rubber/Plastics Blends Based on Waste Materials

Author(s): A.E. Redpath Consulting

Date Published: August 1993

Published by: Research and Development Branch, MTO

Contact Person:

Abstract:

. .

. .

. . .. .

Comments:

Key Words:

Copyright Status:

Dr. A. (Coom) Coomarasamy (416) 235-4678

This study was conducted to determine the technical and economic viability of using waste plastics and scrap rubber for non-structural highway products in Ontario. Information was gathered from a variety of sources via a computer literature survey, a mail survey, and interviews.

Approximately 4,600 tomes of waste plastics per year (mostly from commerciaVindustria1

sources) in the Greater Metro Toronto region are currently not recycled. The technology for recycling and reprocessing waste plastics and rubber is well developed and widely available. How- ever, the technology for production of plastic lumber is yet to be developed. Current production methods are felatively slow, especially when compared to high-speed timber processing systems.

The study concludes that waste plastics based on the four major commodity resins (polyethylene PE, polypropylene PP, polystyrene PS, and polyvinyl chloride PVC) and on scrap rubber would be suitable for certain non-structural highway products.

.

This report is in partial fulfilment of conditions of a grant given to A.E. Redpath Consulting by the Ministry of Transportation under the Ontario Joint Transportation Research Programme. This report was prepared by A.E. Redpath Consulting and documents results of work for which the Ministry of Transportation provided financial assistance. The views and ideas expressed in this report are those of the authors and do not reflect necessarily the views and policies of the Ministry of Transportation, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

scrap tires, waste plastics, pollution, recycling, rubber, polymers, plastics, highway products, blends

Crown copyright 0 1993 Ministry of Transportation, Ontario

i

MAT-92-11

Potential Applications in Highway Products of Rubber/Plastics Blends Based on Waste Materials

A.E. Redpath Consulting

Published by The Research and Development Branch Ontario Ministry of Transportation

Published without prejudice as to the application of the findings. Crown copyright reserved; however, this document may be reproduced for non-commercial purposes with attribution to the Ministry.

For additional copies, contact: The Editor, Technical Publications Room 320, Central Building 1201 Wilson Avenue Downsview, Ontario Canada M3M 1 J8

Telephone: (41 6) 235-3480 Fax: (41 6) 235-4872

August 1993

. R d v D - w MAT-92-11

Table of Contents

Executive Summary ..................................................................................................................... iii

Acknowledgements ...................................................................................................................... iv

1 . Introduction ........................................................................................................................... 1

Assessment of Waste Product Availability ......................................................................... 1

2.1 Plastics ............................................................................................................................ 1

2.3 Rubber ............................................................................................................................ 6

Glossary of Abbreviations ............................................................................................................ iv

2 .

2.2 Plastics in the Waste Stream ........................................................................................... 3

. 2.4 Plastics/Rubber Blends ................................................................................................... 1

Assessment of Processing Technologies ............................................................................. 8 3 . 3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

Overview ......................................................................................................................... 8 Compounding ................................................................................................................. Injection Moulding ........................................................................................................... 9

Extrusion ....................................................................................................................... 10 Rotational Moulding ....................................................................................................... 10

Blow Moulding .............................................................................................................. 11

Compression Moulding ................................................................................................. 11

8

................................................................................................................... Calendering 10

4 . Assessment of Candidate Products ................................................................................... 11

Overview of MTO Material and Product Categories ........................................................ 11 4.2 Economic Viability ......................................................................................................... 12

Discussion of TechnicaVEconomic Viability for Selected Products .................................. 14

5.1 Detailed Reviews ........................................................................................................... 14

Dimensional Lumber Substitutes ..................................................................... 14

4.1

5 .

5.1 . 1

5.1.2 Noise Barrier 16

5.1.3 Traffic Delineators 17

5.1 . 4

5.1.5

................................................................................................... ,

............................................................................................ Sign Blanks ..................................................................................................... 18

Access Hatch / Catchbasin Collbrs ................................................................. 18

6 . Conclusions .......................................................................................................................... 19

Appendix A .......................................................................................................................... 21

References .......................................................................................................................... 25

............................................................................................................ 5.2 General Reviews 18

memorandum @ Ontario

To: Distribution List

From: Dr. A. (Coom) Coomarasamy Research & Development Branch Room 33 1 , Central Building Downsview

Re:

Date: November 30 1993.

Report MAT-92-11 “Potential Armhations in Hbhwav Products of Rubber/Plastics Blends Base on Waste Materials”

Large quantities of waste plastics and used tires are generated in Ontario. Recent estimates show that 60% of scrap tires are still going to landfills. These materials are generally perceived as having potential for recycling into a variety of non-structural highway products.

The attached report is a study conducted by A.E. Redpath Consulting to determine the technical and economic viability of using waste plastics, scrap rubber and waste plasticshbber blends for highway products in Ontario.

The study provides detailed reviews on the technical and economic viability of dimensional lumber substitutes (plastic lumber), noise barriers, traffic delineators, sign blanks and utility access hatch. It also includes an overview of several relatively low volume applications such as railroad crossing mats, paving brick and rumble strips.

Statistics on waste plastics and scrap tire rubber generated in Ontario are discussed with an emphasis on four commodity plastics resins, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and polystyrene (PS).

An entire chapter of the report is devoted to a review on processing technologies for converting plastics materials into finished products.

The study makes several suggestions and recommendations for the use of waste plastics and scrap tire rubber in non-structural highway products.

I will be pleased to receive comments, or discuss the report or other matters relating to the use of waste plastics or scrap tire rubber, and can be reached at (416) 235-4678.

Yours truly,

W - - v c .

Dr. A. Coomarasamy Research Scientist

Attachment

-

!

MAT-92-1 1 RdvD*-

Executive Summary

Ontario generates seven to eight million scrap tires and 300,000 to 400,000 tonnes of waste plastics every year. Almost all the waste plastics and more than 80% of scrap tires currently end up in landfill sites. This is a concern, but there is also a potential opportunity to recycle these mixed plastics and used tires for use in highway applications. These materials may be used in rubber and/or plastics blends to produce non-structural highway components such as noise barrier panels, substrate material for sign blanks, snow fences, and parts of traffic barriers.

a) This study was conducted to determine the technical and economic viability of using waste plastics and scrap rubber for non-structural highway products in Ontario. Information was gathered from a variety of sources via a computer literature survey, a mail survey, and interviews.

b) The study concluded that waste plastics based on the four major commodity resins (polyethylene PE, polypropylene PP, polystyrene PS, and polyvinyl chloride PVC) and on scrap rubber would be suitable for certain non-structural highway products such as:

delineators;

snow fencing;

picnic tables and benches;

fence and sign posts; and possibly for:

guiderail components;

noise barriers;

access hatch collars and risers;

culverts.

c) The principal advantages of plastics and rubber/ plastics blends for non-structural highway products when ussd in the forms of lumber-type profiles, sheets, or moulded shapes are:

excellent durability (long service life expectan- cy in outdoor exposures):

maintenance-free service;

good balance of mechanical properties; good fastening characteristics (can be nailed,

stapled, bolted, glued);

dimensional stability;

no splitting, splintering, or cracking;

can be sawed, drilled and routed.

d) The main disadvantages of plastics and rubber/ plastics blends are:

relatively poor modulus;

creep performance;

flammability;

cost (compared to wood and concrete). A 1990 supply survey, conducted for the Minis- try of the Environment, established that approximately 4,600 tonnes of waste plastics per year (mostly from commerciallindustrial sources) in the Greater Metro Toronto region are currently not recycled. The technology for recycling and reprocessing waste plastics and rubber is well developed and widely available. However, the technology for the production of plastic lumber is yet to be developed. Current production methods are relatively slow, especially when compared to high- speed timber processing systems.

e)

f)

Recommendations The recommendations presented here are in two parts. First, non-structural highway products are considered where plastics are the main material of composition. Second, products are examined which are not currently made of plastics but where substitution of waste plasticdrubber-based materials may be viable.

a) For non-structural highway products, such as delineators, which are already made of plastics, MTO should consider specifying a minimum content (e.g., 50% initially) of recycled plastics resins. This policy should be phased in over a reasonable time to ensure manufacturers' access to recycled resins and to peni t modifica- tions to their processing equipment.

When plastics andor rubber based products are taken out of service, MTO should collect and retum these materials to recycling companies.

For non-structural highway products composed of materials other than plastics or rubber (e.g., wood, concrete, steel or aluminum) the question becomes: "Is substitution of plastics a viable op- tion?" This key question cannot be answered satisfactorily on the basis of laboratory data for material properties and performance, but requires additional information from field tests and trials. MTO should apply its system of compre-

b)

c)

... - 111 -

MAT-92-11

hensive field testing procedures prior to contem- plating any substitution of waste plasticdrubber based materials for non-structural highway applications.

Currently, the most readily-available commercial waste plastics products are the synthetic wood substitutes called “plastic lumber/timbers”. There are at least nine manufacturers in North America, with operations both in Canada and the U.S. The MTO should consider a trial substitution of plastic lumber in place of treated or regular lumber for picnic tables and benches.

The MTO should consider field testing plastic lumber/timbers for certain low stress non- structural highway applications. For example, fence and sign posts, secondary highway guiderail posts, and small size si@ blanks.

The MTO stresses the importance of safety, performance and cost in its selection of materials and products. In view of these considera- tions, the Ministry should consider applied R&D to generate material performance and safety information about waste plastics/rubber-based products. This program may be undertaken in a cost-effective manner on a partnership basis with prospective suppliers and university research groups. We have identified the following areas where published or otherwise available information about plastics, rubber and/or rubber/ plastics blends based on waste materials is lacking:

Flammability characteristics such as ignition, flame spread and the possible generation of toxic fumes or dense smoke. Such information is particularly important if the plasticdrubber materials are to be used where vehicular crashes or grass/brush fires might ignite them.

Long-term creep performance of materials or products. Creep is generally a weakness of thermoplastics and rubber-based products. Yet if rubber/plastics blends were to be used for sign posts or sign blanks, where they must withstand static and/or dynamic wind loads under varying temperature conditions, creep may be a problem.

Mechanical properties at extremes of service temperature. It is normally expected that elevated temperatures of 35 to 40°C would tend to increase the plasticity and creep of rubber/ plastics blends. On the other hand, very cold temperatures of -35 to -45°C embrittle these materials. Reliable information about low vs. high temperature behaviour is lacking.

Leachability of possible contaminants or material residues. Since waste plastics from which highway products might be made are to be diverted from the waste stream, it is conceivable that they might contain food and/or chemical

residues which might be leached from the finished product.

Repeated recyclability of products made from waste plastics / rubber blends.

The Ministry should continue to monitor R&D and commercial activities in the recycling of plastics and rubber. The Ministry should assist manufacturers in the private sector in the development of new products by continuing to provide technical expertise and support.

g)

h)

Glossary of Abbreviations

ABS Acrylonitrile butadiene styrene copolymer

EPDM Ethylene propylene diene monomer

HDPE High-densrty polyethylene

LDPE

LLDPE

MFI

MOE

MTO

P E

PET

PS PVC

SAN

Low-density polyethylene

Linear low-density polyethylene

Melt flow index

Ministry of the Environment, Ontario

Ministry of Transportation, Ontario

Pol yet h ylene

Polyethylene terephthalate

Polystyrene

Polyvinyl chloride

Styrene acrylonitrile copolymer

Acknowledgments This study was guided by David Manning and Coom Coomarasamy of the Research and Development Branch of the MTO; their valuable advice and suggestions are gratefully acknowledged. The many individuals and organizations listed in Appendix A also contributed their input. The advice and information they shared is much appreciated. In particular, members of the MTO engineering staff gave freely of their time to provide valuable suggestions. We are grateful to Peter Lee for his valuable help in the computerized data search and word-processing of the manuscript. We are also grateful for the time given by Greg Barber of the MTO library and for his assistance in the computerized data search.

- 1v -

t MAT-92-11 1

1. Introduction The management and disposal of solid waste has become a serious environmental, economic and political problem in Ontario, and throughout the industrialized world. The traditional methods of waste disposal such as incineration and sanitary landfill have become both expensive and often unacceptable because of associated environmental problems. For example, Metropolitan To- ronto must dispose of over three million tonnes of solid waste annually 111. The scarcity of landfill sites in all major metropolitan areas and in many regional municipalities is a very serious problem. Concurrent with the expanding volumes of waste, natural resources are being depleted at an alarming rate. Unfortunately, most industrial processes have a linear design. The fundamental energy and material flow pattern is:

manufacture +

Since resources are finite and many are non-renewable, it is essential that policies such as the "3-Rs" (reduction, reuse and recycling) be implemented to slow resource consumption. Reduction and reuse both restrict the amount of material flowing through the linear process outlined above; where these two approaches are not feasible, recycling creates a cyclic flow system. Material recycling simultaneously reduces over-demand on resources and eases the pressure of waste disposal - it would, therefore, reduce the threat of resource shortages and also that of pollution.

A special concern, and also an opportuntty, is the possible recycling of mixed waste plastics and used tires. The desirability of this has been recognized by environmental programs such as the Federal govemment's En- vironmental Choice program which has categories either in existence or under consideration for products made from recycled plastics and from scrap tires (21. Ontaio generates large quantities of used tires [3] and waste plastics [4]. These materials have the potential for use in rubber and/or plastics blends to produce non-structural highway components such as sound barrier panels, substrate material for sign blanks, snow fences and posts, and traffic barriers.

Conventional plastics processing technology has recently adopted polymer blending as a widely practiced method of modifying the properties of polymers. For example, blending rubber in small proportions with plastics results in blends and elastomeric alloys with improved impact resistance and flexibility. The blends and alloys can be processed into finished products using conventional thermoplastic processing techniques such as injection moulding, extrusion, and calendering. Polymer blending thus provides a route for incorporating waste plastics into production systems. Technology is available for converting these materials into foamed products with en- hanced noise control characteristics and sound barrier properties. The main advantages of these materials are their light weight, they have good physical properties, they can be easily processed into finished products, and they are durable.

natural resources + extraction product use +waste + dump.

The present study addresses the problem of mixed plastic waste and used tires in Ontario. The concept of using these materials for non-structural highway products may create a substantial market, provided the candidate products would be economically viable and meet the technical and safety specifications of the Ministry.

Thus, the objectives of the present study were:

a) To assess the economic and technical viability of using waste plastics and rubber for highway products.

b) If the assessment suggests viability, to prepare recommendations for implementation and possible research and development needs to facilitate implementation.

(Note that pavement applications of polymers are ex- cluded from this study.)

The study is based on information collected by a number of different means. A comprehensive computer literature survey was performed, primarily to determine the state- of-the-art in reported technology for recycling of plastics and rubber. A second focus of the computer literature survey was to scan the applications literatwe for specific examples of existing highway products which use recycled materials. In addition to the computer survey, a series of personal interviews were conducted with a selection of stakeholders including personnel from MTO and MOE, municipal waste managers, representatives of trade organizations, companies active in the recycling of plastics or rubber, companies making products from recycled plastics or rubber, and academics active in research into recycling technologies. These interviews were supplemented by a telephone and mail survey of a more extensive list of companies manufacturing or marketing products made from recycled plastics or rubber. Each of these information collecting activities is described in more detail in the Appendix.

2. Assessment of Waste Product Avail a bi I ity 2.1 Plastics

A brief overview is presented here about plastics materials, additives, their properties and uses. More comprehensive information may be obtained from reference texts, such as annual editions of the Modem Plastics En- cyclopedia [5].

In general, plastics can be grouped into one of two major classes; thermoplastics and thermosets [6]. Thermo- plastics are based on linear or branched polymers. They become rigid when cooled and soften at varying elevated temperatures, depending on resin type and additives. Thermoplastics are capable of repeated softening and hardening in response to heating and cooling. Typical thermoplastics are polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), acrylics, poly- esters, and nylons.

Thermosets, on the other hand, are materials based on cross-linked polymers. They harden permanently with the aid of catalysts and/or heat. They cannot be re-melted

2 MAT-92- 1 1 R c r u L z c e W - w without degrading their polymeric structure. Typical plastics of the thermosetting family include phenolics, epoxies, alkyds, polyurethanes, melamine- and urea- formaldehydes.

To meet the requirements of various end uses most plastics generally contain different additives. The physical mixture of polymer and additives is called a "plastic compound''. The process of mixing additives with the base polymer is referred to as "compounding". The base resin in a compound may be a homopolymer or copolymer, or it may be a mixture of the two.

The main classes of the various additives used in the manufacture of plastics products are as follows:

lubricants impact modifiers stabilizers reinforcing agents plasticizers fire retardants fillers colorants

Thermoplastics represent over 80% of all plastics manufactured. Of these, the four major commodity resins (polyethylene PE, polypropylene PP, polyvinyl chloride PVC and polystyrene PS) represent nearly 75% of all synthetic polymers produced annually or about 75 million tonnes world-wide.

A brief description of each of the four main thermoplastics follows. Their key properties are summarized in Table 1.

Polyethylene Polyethylene is a crystalline hydrocarbon thermoplastics having the basic unit:

-CH*CH2-

The structure of the polymer molecule can be altered by the choice of catalyst and reaction conditions [5]. Nearly half of the world production of plastics materials includes various grades of polyethylene which is used in such diverse products as moisture barriers on milk and food car- tons, thin films for grocely and garbage bags, milk and water bottles, gas and water pipes, housewares, caps and closures, power cable sheathing, drums and industrial containers. The unbranched homopolymer (called linear polyethylene) has the highest density (0.96gIcm3)

and highest melting temperature (133"C), and is therefore commonly called "high-density pclyethylene" or HDPE. The properties of the homopolymer can be modified by copolymerization with higher alkenes such as bu- tene or hexene, giving rise to a large variety of copolymers which can be characterized by their densities. According to ASTM there are four resin types, as indicated in Table 2.

Table 2 ASTM types of polyethylenes ~~

Tvoe Densitv Wcm 3) ~

I 0.91 0-0.925

I1 0.926-0.940

I11 0.941 -0.959

N 20.960

Types I and II are referred to as low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE), according to the method of manufacture. Polyethylenes having a density greater than 0.941 g/cm3 are referred tc as high-densty polyethylenes (HDPE). In addition to density, molecular weight and molecular weight distribution play an important role in establishing the properties of polyethylene. Most often the molecular weight or viscosity is expressed in terms of Melt Flow Index (MFI) expressed in g/10 min. As the molecular weight increases, the viscosity increases and the MFI decreases. Typically, MFI values range from 0.1 to 100 g/l 0 min.

Various additives may be used to impart oxidative stability during processing or in service. Inorganic or organic fillers are commonly used to impart greater rigidity, and to increase creep resistance and tensile strength. The outdoor weather resistance may be markedly improved by the addition of carbon black which acts as a powerful light (W) absorber. The relatively soft nature of polyethylene and pronounced creep rates, even at moderate

''. temperatures, tend to exempt this polymer from applications which involve large stresses.

Table 1 Properties of common thermoplastic resins IS]

Property PE PP wc PS

Density g/cm3 0.92-0.96 0.9 1.5 1.07

Tensile modulus, GPa 0.2-0.5 1.6 3.5 4.0

Flexural modulus, GPa 0.3-0.7 1.8 3.5 4.0

Tensile strength, MPa 9-34 38 45 84

Flexural strength, MPa 13-20 50 110 100

Softening point, "C 100-130 170 105 120

Compression strength, MPa 20-25 47-56 73-91 100-105

Heat deflection temp., "C 40-91 120 82 107

Glass transition temp., "C -25 -20 75-1 05 75-1 05

Polypropylene Polypropylene (PP) is a crystalline isotactic hydrocarbon polymer with a melting point near 168°C [6]. The repeat unit of the homopolymer is:

CH3 I

- CHzCH -

A key property of polypropylene is its low density (0.90 g/cm3), making it the lightest among the major plastics. It has been found suitable for continuous low stress structural applications up to 135°C. The homopolymer has a flexural modulus of 1.7 GPa, which makes it the stiffest member of the polyolefins. Chemical resistance extends to aqueous acids

MAT-92-11 3 R d % D - w and bases, low boiling hydrocarbons, detergents and al- cohols. Polypropylene is subject to oxidative degradation which is catalysed by ultraviolet radiation. Therefore antioxidants and ultraviolet absorbers are commonly employed to protect the polymer during processing and in service conditions.

Random copolymers are made by introducing small amounts of ethylene monomer (24%) which increases toughness at the expense of stiffness. By blending rubber, such as EPDM, with the homopolymer, the low temperature brittleness can be improved to achieve increased impact toughness. Polypropylene may be co- compounded with a variety of organic or inorganic fillers such as wood fibres, glass fibres, talc, calcium carbonate or mica, in order to increase selected mechanical or ther- mal properties.

Polypropylene is used in a variety of textile applications, particularly carpets, upholstery, apparel, diapers, engineering fabrics (geotextiles), and heavy-duty bags. Re- lated applications include rope, twine, strapping, and bristles. Packaging is a growing outlet in fast foods, bak- ery goods, moulded containers, bottles, and closures. In durable goods, polypropylene is used in automobiles and appliances. Most battery casings are made of polypropylene. The low cost and high performance of polypropylene makes it the second most important synthetic polymer in the world.

Vinyl Copolymers Polyvinyl chloride (PVC) is the most significant member of this group which contains the repeating unit:

CI

-CCHzCH- I

PVC is used extensively due to its combination of properties including corrosion resistance, fire resistance, physical strength, and its ability to be modified through compounding [5]. General purpose homopolymers may be blended with plasticizers for a variety of applications. Rigid resins contain l i l e or no plasticizer and are useful in building and structural applications where high strength and stiffness are required. By far the largest single application for PVC resins is for pipes. Other applications include electrical conduit, pipe fittings, siding, downspouts, gutters, door and window frames, bottles, packaging, coatings, flooring, footwear, coated fabrics, and automotive components.

Unmodified PVC is strong but vety brittle. Therefore, impact modifiers such as nitrile rubber are commonly added to increase fracture toughness. PVC is resistant to ultraviolet radiation, which is important for outdoor applications. It has a glass transition temperature between 75 and 105°C. The rather large density of 1.45 g / C d is due to the high chlorine content (57%). It is difficult to recycle PVC due to its sensitivity to impurities and heat. However, this may not be a problem with larger objects such as railroad ties.

Po I ystyre n e This broad class of resins includes styrene-acrylonitrile (SAN) copolymers, acrylonitrile-butadiene-styrene (ABS) copolymers, rubber-modified polystyrene, and styrene- maleic anhydride (SMA) copolymers [5]. Polystyrene is an amorphous polymer with the aromatic repeat unit:

- CH2CH -

4 in which the phenyl substituent confers strength and rigidity. The homopolymer has a density of 1.05 g/cm3, which is intermediate between the polyolefins and the vinyls. Some copolymers may soften at temperatures as high as 107°C. Polystyrene is susceptible to degradation by ultraviolet radiation, but may be protected by UV stabilizers or carbon black. Polystyrene is very resistant to chemical attack which may include alkaline chemicals, acids, detergents, and moisture. The extreme weather resistance of polystyrene is often noted in regard to litter (e.g., foam polystyrene drinking cups). The brittle nature of polystyrene is modified by the addition of various rub- bers, either during the polymerization process (such as ABS) or by subsequent compounding (impact grades). The addition of a rubber modifier tends to decrease the stiffness and strength slightly. Polystyrene is soluble in aromatic hydrocarbons and chlorinated solvents, and is also susceptible to gasoline, oils and greases. Poly- styrene is readily foamed by the use of chemical blowing agents to produce lightweight insulating materials or slightly expanded structural foams.

The applications for polystyrene are extensive and range from simple household items to sophisticated parts for the electronics industry, automotive components, packaging films, video cassettes, television cabinets, furniture items, refn'gerator linings, fast-food trays and glazing materials. Styrene-acrylonitrile (SAN) resins possess greater heat deflection temperatures and greater solvent resistance (by virtue of the acrylonitrile content) but may still be attacked by aromatic hydrocarbons, chlorinated compounds, ketones and esters. Weatherable grades are used in glazing, storm doors and outdoor signs. Styrene- maleic anhydride resins are polar polymers (due to the anhydride functionality) which are specially designed for filler reinforcement. Automotive applications include electrical connectors, instrument panels, consoles, heating ducts, wheel covers and lamp housings. The superior heat resistance of SMA resins makes them useful in cof- fee makers, steam curlers, power tools, business machines, vacuum cleaners, food service trays, door panels, pump components, and fan blades.

2.2 Plastics in the Waste Stream

Reliable estimates on the quantity and types of plastics in the waste stream are difficult to obtain. Yet such information is vital to prospective producers of waste plastics/rubber-based non-structural highway products. They need to know the volume reliability and cost of available

4 MAT-92-11

feedstocks. The MTO, as a potential purchaser of recycled material-based products, is also keenly interested in these issues. Purchasing policy should not be based on good intentions and unreliable economics.

Therefore the approach of MOE and its expert consul- tants was followed in estimating the quantity, availability and types of plastics in Ontario. The first level of estimates are based on statistics and trends in the consumption of virgin plastics resins.

Aggregate statistics on plastic resin consumption can provide an initial clue to waste plastics generation. For example, Canada consumed over 2 million tonnes of plastic resins in 1986 and approximately 2.5 million tonnes in 1990 (Table 3). Ontario used about 1.2 million tonnes in 1986 (approximately 60% of the total) and 1.5 million tonnes in 1990. Major industrial sectors using plastic resins are packaging, buildingkonstruction, consumer products, and automotive/transportation. It is expected that these sectors will grow in their use of plastic resins and retain their relative positions in overall consumption of plastics [4, 7, 81. Consumption of major resins grew by about 25% from 1986 to 1990, led by the polyolefin group (PE and PP). Plastics are generally perceived as used in applications such as packaging which have a relatively short life and thus have the potential to become waste very quickly. However, the majority of all plastic resins (about 54%) are utilized in products with a relatively long life-span such as automobiles, construction materials, consumer products, electronics, and agriculture [8]. Therefore waste plastics (short life span products) represent about 45% of resin consumption. However, taking exporVimport balance into account, only about 30-35% of plastics products end up in the waste stream after a short period of use.

A second approach to estimating the quantity and type of waste plastics is based in the analysis of solid waste. This approach was also employed as a form of cross-

.

Table 3 Canadian consumption of plastic resins (Id t)

ResinType 1986 1987 1988 1989 1990 1991

LDPE

HDPE

PS

PVC

PP

Polyester

ABS

Other

452

248

187

327

152

121

52

482

475

262

196

350

163

129

54

514

498

276

205

374

175

137

56

549

523

291

2l5 399

188

145

58

586

549

307

226

427

202

155

61

625

577

324

236

456

217

155

63

668

Total 2021 2142 2270 2407 2552 2697

Sources: Stats. Can., MOE [8] (Note : other resins include acrylics, polyamides, polyurethanes, epoxies, polycarbonates, phenolics and ureas).

reference, to compare to the waste estimates based on plastic resin consumption.

The estimated total industrial, commercial and residential solid waste disposed in Canada in landfill is 10 million tonnes. By excluding the estimated 2.0 million tonnes of demolition waste, plastics have been estimated to generate approximately 7% (or about 600,000 tonneslyear) of the waste stream sources during the period 1986 io 1990 (Figure 1). Waste composition sources are varied. They range from households to restaurants to clothing stores to offices, instiutions, heavy and light industry. Waste plastics are available from all of these sources. In- plant use of waste plastics from off-spec products is estimated to be 25% of total primary production. The reuse of plastics reduces the potential industrial generation of waste pl&ss;ics and is a cost-effective production and waste management course of action for the industry. Post-consumer waste plastics currently end up in landfill.

Statistics on materials recovered are difficult to determine because the plastics industry makes every attempt to reuse under-spec products to the greatest extent possible. The extent of reclaim and recycling of plastics will be determined by increasing demand for the lightweight and high-strength plastics, relative prices of virgin resins, availability of sufficient scrap, widening of the price differential between virgin and scrap materials, and the initial design of plastics products to enhance their recycling and recovery.

Prices for compounds are related directly to the primary costs, as passed on by the major producers and suppliers of resins. Prices for scrap are related to availability and the supply of primary resins. Generally, prices are 10 to 20% lower than those of primary prices. Prices for scrap track the prices for primary resins; when prices rise, the supply of scrap becomes tighter as substitution becomes more prevalent [8].

Table 4 Estimates of annual quantity of plastic waste generated in Canada and Ontario (1 03 t)

Resin Canada Ontario Canada Ontario Canada Ontario Type

LDPE 185 102 204 112 220 123

HDPE 88 48 99 52 108 60

PS 67 38 76 40 81 43

PVC 69 ’ 39 79 42 87 45

PP 32 19 26 18 32 20

Polyester 24 13 24 12 26 14

ABS 8 5 10 6 10 6

Other 95 48 104 53 105 55

Total 568 312 622 335 669 366

Source: MOE survey

MAT-92-1 1 5 RL.tULZCevD-w

Origin of waste

Scrap plastics are recovered by the user industry, either in-plant and reused in extrusion processes or recom- pounded. In addition, the waste exchange provides the opportunity to list plastics as contaminated resins or the various types of plastics in whole product form, granules, flakes or the mixed form (Figure 2).

The contribution of plastics to the waste stream in On- tario is estimated to be just above 300,000 to 400,000 tonnes per year (Table 4). Of this large potential quantity, 20 to 30% could readily become available for recycling if the larger municipalities included plastics in their blue box programs. In the Greater Toronto Area, waste plastics potential supply estimates range from 20,000 to 40,000 tonnes per year [8].

CONSUMER MANUFACTURING . AND TRADE

I METAL, 8% I

oUTSloE THE MUNICIPAL

WASTE STREAM

I PLASTICS, 7% t

MUNICIPAL WASTE STREAM

POLYOLEFINS, 65%

RETREAD RESALE LANDFILL STOCKPILE RECYCLE EXPORT 4,222,200 717,000 630,200 236,300

POLYSTYRENE, 15%

OTHER 107,500

POLY VINYL

POLYETHYLENE CHLORIDE, 10%

TEREPHTHALATE, 5% OTHERS, 5%

Figure 1 Plastics in the municipal solid waste stream by mass (source: P.G. Claus, 1988)

Waste collection

Waste treatment

Recycling alternatives

Final state

SEPARATION

RECYCLING INCINERATION DISPOSAL

- I

PRODUCTS/

ENERGY WASTE LANDFILL

Figure 2 Waste plastics recycling and disposal flow

legend: LF - landfill RT - retread ACCIDENTS SCRAPPED TIRE SALES

RC - recycle RS - resale

MANU- FACTURERS

SP - Ex- OT -

total total

stockpile export other

tires: demand:

6,812,300 5,398,700

I

WRECKERS 390,000 RS 455,000 LF 455,000 SP i n I DEALERS I

590,800 RC 262;OOO SP 295,400 LF 107,500 OT 236,300 EX L

59,100 RS

OFF-SPEC TIRES

113,600 LF

Figure 3 Passenger car tire flows in Ontario

R d % ? I * W 6 MAT-92-1 1

2.3 Rubber "Rubber waste" can refer to a wide range of products, made from an equally wide range of rubber compounds. In practice, however, the rubber waste stream is so dom- inated by scrap tires that waste tire management is virtually synonymous with waste rubber management. There are several reasons for this:

scrap tires make up over 90% of the total rubber waste stream; yet no collection system exists to cap- ture the diverse array of consumer and industrial products that make up the remaining 10%; scrap tires represent a relatively uniform waste stream that is readily identifiable and thus (at least potentially) readily collectable.

Other waste streams do exist-two of the largest are tire trim and off-spec tires from tire production, and buiiings from rubber product manufacture. While these represent a significant fraction of the recycled rubber currently used, their potential is small when compared to the potential from tires. These factors, combined with a number of environmental disasters associated with fires in stored tire piles, have made the management of scrap tires a priority issue. This report therefore focuses on scrap tires as the source of waste rubber.

Scrap tire management practices in Ontario have been thoroughly reviewed in a report prepared for the Waste Management Branch of the Ontario Ministry of the Envi- ronment and issued in January 1991 [3]. The report estimates that seven to eight million used passenger car tires are generated each year in Ontario, with a further five million passenger tire equivalents coming from light- and heavy-duty truck tires. Nearly two million passenger tire equivalents due to the truck tires are either retreaded or resold; the remainder are disposed of in a fashion similar to passenger car tires. For the passenger car tires,

I WH0L:TlRES 1

CRYOGENIC CHAMBER

I HAMMERMILL I I

I SCREENING I

FIBRE SEPARATION FIBRE

BULK OR BAG

Figure 4 CIyogenic tire grinding process - schematic outline

approximately 14% are resold as used tires. Currently, there are virtually no sales of retreaded passenger car tires. The remaining 86% are disposed of via a number of different routes: landfilling (71 %), stockpiling (1 2%), recycling (1 1 %), export (4%) or other (2%). A chart summa- rizing the flow of scrap passenger car tires is reproduced from the MOE report as Figure 3.

It is important at the outset to gain an appreciation of the magnitude of the quantity of scrap rubber available from scrap tires. For the processing technologies discussed below, it is estimated that each tire generates between 6 and 7 kg (12 - 15 Ib) of rubber. The tires generated in Ontario thus represent an approximately 40 - 50 million kilogram source of rubber annually. When discussing product applications this number can be used to provide some idea of the number of articles that would have to be produced to have a significant impact.

Considering the uses for whole tires first, the largest application for whole tires has historically been retreading. As mentioned, however, the design of modem radial passenger car tires, coupled with consumer perceptions of inferior quality, have limited the amount of retreading in the recent past. The technical capability for retreading does exist, however, and finds extensive use in retreading of the higher value truck tire carcasses, whose value justifies the expense of retreading. Retreading of passenger car tires is now being reconsidered in view of the waste tire disposal problem. The primary technical issue to be overcome is determining the integrity of the tire carcass to be retreaded. Techniques such as X-ray analysis can be used to ensure carcass viability. One ideal application for retreading would be for controlled vehicle fleets, where history of the tire usage, tire maintenance, etc. are all well documented. Trials are already under

WHOLE TIRES I

I MAGNETIC

S EPAR AT0 R STEEL

PRIMARY SCREENING ! FIBRE SEPARATION FIBRE

SECONDARY

I FINALSCREENING I I PACKING 1

Figure 5 Ambient tire grinding process -schematic outline

MAT-92-1 1 7 R c 4 u d v D - W consideration or underway for several vehicle fleets in Ontario. Other applications for whole tires include artificial reef formation, breakwaters, dock bumpers, highway crash barriers and tailings pile stabilizers.

Although these uses for whole tires exist, scrap tires are perhaps best viewed as a raw material feedstock for a number of processes that produce upgraded waste products for use in subsequent operations. These processes can be divided into energy reclamation, chemical processing and physical processing. Energy reclamation recognizes the fuel value of tires and has led to the use of either whole tires or shredded tires (tire-derived fuel) as a supplemental fuel in a variety of furnace or kiln applications. Chemical processing refers to a variety of technologies that pyrolyse tires, recovering a series of chemical streams usually characterized as an oil stream, a gas stream, a recovered steel stream, and a char stream containing carbon black and inorganic pigments and processing compounds. While both energy reclamation and chemical processing have been well reviewed in the MOE paper already referred to [3]; neither has much relevance for the focus of this particular study. Physical processing, however, does.

Both mechanical (ambient temperature) and cryogenic (low temperature) processes exist for grinding tires into small particles called rubber crumb. Figures 4 and 5 schematically outline the cryogenic and ambient grinding processes, respectively. Both processes rely on some means of shredding and grinding the tires, with the cryogenic process using liquid nitrogen to embrittle the tires first, thus reducing the grinding energy costs at the expense of the energy costs of preparing liquid nitrogen. Both. processes separate out the steel and fibre belting materials and screen the resultant crumb into a range of particle sizes. Particle size plays an important role both in the cost of grinding and on the uses to which the crumb can be put. A typical size distribution would produce cuts of 5 - 10 mesh, 10 - 40 mesh and > 40 mesh. (These are averages-each process will produce its own particular set of mesh sizes, depending on the grinding process, screen sizes etc.) The finer the mesh size the higher value of the product with quoted price ranges falling between 136kg (6Mb) for the coarsest mesh to over 4 4 ~ k g (20wlb) for the finest. Actual individual quotes were 13$/ kg (6vIb) for “coarse mesh”, an average of 22Ukg (1 O$/ Ib) for a range of mesh sizes and 26 - 53uikg (12 - 2 4 d Ib) for a range of mesh sizes.

For the bulk of the potential applications of recycled rubber discussed in Chapter 5, the end product is formed by taking crumb of the appropriate mesh size, adding a binder (a polyurethane, for example) and thermally curing the mixture in a mould. The choice of mesh size is gov- erned by product size, surface finish desired, and price tolerance. For some applications, however, more complex chemical and physical factors come into play. Rub- ber Crumb has been proposed as a low-cost filler for polyolefins such as polyethylene. As such it generally reduces the physical performance of the plastics unless compounding agents are added. Different sources of nominally the Same mesh size crumb can show markedly

different behaviour in these applications. It is clear that factors such as particle shape and surface area are important in these applications. Products manufactured from rubber crumb include athletic track surfaces, dock bumpers, truck mud flaps and mats.

Current total consumption of crumb in Ontario has been estimated at 25,000 tonnes/yr [3]. Current production is likewise estimated at 7,000 tonnedyr. This latter estimate must be taken with caution since several new, large production facilities have been proposed and may come on stream. It is still clear, however, that a majority of the crumb used in Ontario is imported - due, historically, to reasons of capacity, quality, reliability and pricing. It is also clear that the total crumb used is still only a fraction of the total potentially available from tires. Not surpris- ingly, since tire usage is correlated with car usage, scrap tires are distributed in the same manner as the popula- tion in Ontario. In terms of usage as a feedstock, most tires will thus be available in southkentral Ontario, where processing facilities are also likely to be located (and where all current facilities are).

2.4 Plastics/Rubber Blends The potential for preparing blends of plastics containing various quantities of rubber has already been referred to - both in the Introduction, with reference to impact- modified polystyrene, and in Section 2.3, with reference to rubber/polyolefin blends. The impact-modified polystyrene application is used in millions of kilograms annually, but is generally not considered in the context of recycled polystyrene or recycled rubber. The rubber/ polyolefin blends application has generated considerable interest because of its potential for use of recycled materials, but has achieved little commercial application. The key, of course, lies in the effect that adding rubber to the plastics matrix has on the properties of the mixture. In the case of impact-modified polystyrene, the physical property of interest is improved. In the case of polyethylene, generally the properties of the blend are poorer than those for pure polyethylene. Baker has investigated this thoroughly [9] and determined that the shape of the rubber particle, as well as the mesh size, has an important bearing on the performance of the blends. Figure 6 shows a plot, taken from reference [9], of impact strength

0 10 20 30 40 50 60 rubber phase

Figure 6 Impact strength vs. % rubberphase in linearlow- density polyethylene

a MAT-92-1 1

vs. % rubber phase for rubber in linear low-density polyethylene. While impact strength is uniformly worsened by the addition of rubber, it is important to note that by reactive compounding or mixing (upper curve in Figure 6) the degree of change is markedly decreased.

It is likely through the use of compounding agents that blends of rubber in plastics, and blends of various different plastics will achieve desired physical properties. Work on polystyrene/-polyethylene blends [I 01 and on polyethylene/-polypropylene blends [l 11 supports this. Peroxide catalysts have regularly been used in molecular weight modification of polyolefins - reduction in the case of polypropylene, crosslinking in the case of polyethylene. This concept is being extended in two ways. First, in-situ reactive compounding agents can be used to compatibilize blends during compounding. An equally promising route uses chemical grafting or an equivalent process to pre-modify a small amount of polymer that then serves to compatibilize two normally incompatible plastics (121. It is clear, however, that this work is all at early stages yet and will require considerable further research before commercial applications are in place.

3. Assessment of Processing Technologies 3.1 Overview

The primary purpose of this section is to provide an overview of the unparalleled flexibility and versatility of plastics processing technologies. Further, to discuss some of the technical problems involved with the recycling and reprocessing of commingled and contaminated plastics. These issues are of concem to MTO and prospective suppliers of recycled plastics or rubber based non- structural highway products.

The reclaim market has been in business as long as the plastics industry but has recently become more sophisticated in order to meet government regulations con- ceming waste recovery. Secondary recycling utilizes waste plastics which are unsuitable for direct reprocessing using standard plastics processing equipment. Com- mercial equipment is available for recovering urban and industrial waste and pelletizing it for reuse. Mixed plastics may be scanned on a conveyor and automatically separ- ated according to type. The natural reluctance ,of processors to use recycled material is due to contamination and variability. Attempts to use reclaim have sometimes led to lawsuits due to product failures so that manufacturers are often reluctant to assume liability. Hence the recycling business has tended to focus on producers that can tolerate variability and do not require stringent specifications [13,14,15].

There is a ready market for uncontaminated plastics which may sell for a slight discount. Waste plastics tend to be contaminated with non-plastic substances such as food residues, metals, sand, etc. which may pose a dan- ger to the processing equipment, as well as product quality. Various plastics in the mixture (commingled plas-

tics) tend to be mutually incompatible, thereby resulting in a product having poor mechanical properties.

To facilitate separation (by hand or otherwise) the Society for Plastics Industry has introduced a numerical coding system to appear on products to identify the plastic resin used [16]. Even polymers of the same type may be incompatible if their molecular weights differ appreciably. The aging resistance of polymers can be greatly affected by minute traces of metals (e.g., iron and copper) which can catalyze oxidation. Certain organic cordarninants (acids, bases) can have a profound effect in processibility and long-term performance. Since the cost of purification may be prohibitive (resulting in a resale price which is greater than that of virgin resins), it is evident that the use of recycled materials usually carries an unknown risk [17,18,19 1. Waste plastics are often coloured and non- transparent, which can further limit their market potential. Lastly, to be economically viable, there must be a steady reliable volume of waste plastics in quantities sufficient to satisfy a mass-produced item. At the present time, the plastics industry is struggling to resolve these massive problems. Canada has the dubious distinction of having the largest waste generation per capita of the developed countries (1.7 kg/day) and recycling or converting into energy only 18% of its waste.

The following section describes in general terms the types of equipment commonly employed in the plastics industry and how they might be adapted for products containing recycled materials.

3.2 Compounding The first stage in the manufacture of a product begins with compounding in which all the required ingredients are mixed together. In the rubber industry, the Banbury mixer is the workhorse that accomplishes this function. It is a giant two-story batch mixer that masticates 200 kg of rubber and carbon black for several minutes before discharging it onto a two-roll mill that consolidates the hot rubber into a thick sheet. This type of equipment was often used for compounding plastics although today most plastics compounding is camed out in a single screw or twin screw compounding extruders.

For processing regrind, several safety features are recommended. These include various types of sensors to detect impurities in the feed which will automatically di- vert contaminated batches to a holding pan. For example, a metal detector can be placed in the teed zone set to discharge any contaminated material.

Occasionally, the presence of vinyl PVC-type resins can be harmful in commingled waste and must be removed prior to processing. This type of problem has not yet been satisfactorily resolved. However, equipment is available for scanning a conveyor system to identify the composition of individual containers so these can be sorted according to type. This stage should remove most of the potential hazards.

In addition to screw-type compounders, there are special high-intensity batch mixers which are sold under the tradename Gelimat. These rugged mixers are capable of

MAT-92-11 9 R d V D U W fluxing most compounds within a few seconds using sturdy impellors which rotate at high speed. The kinetic energy imparted to the resin mixture rapidly heats the charge until a preset temperature sensor opens a trap- door and discharges the hot mass into a pelletizer. A Ca- nadian company, Synergistics Inc., has pioneered the use of this mixing method in North America under the trade name K-Mixer. This type of equipment is particularly suitable for sensitive materials such as vinyl resins. The University of Toronto has pioneered the development of high-speed intensive mixing for the production of wood fibre composites from waste plastics and paper [17].

Once the method of mixing has been established, the next step is to formulate the compound recipe. Fre- quently, the plastics materials are pre-blended in a high- speed mixer of the HenschelTM, CovemaTM or Pa- penmeyerTM types. After all the additives are thoroughly distributed, they are then mixed and extruded into pellets. A typical compounding extruder will process 10,000 k g h and may cost one million dollars to purchase, including various accessories. In the case of waste recycling the composition of the mixture is unknown so that it may be prudent to add a stabilizer package to protect the polymer during processing and in service. Per- sons who are skilled in selecting the correct heat/ antioxidanUight stabilizer package are quite rare since it requires a long time to become an expert. This position is analogous to the rubber compounder. The stabilizer package will vary in amount and type, according to the type of resin and intended service conditions. After the stabilizer package has been selected, other additives may be required (such as lubricants, compatibilizers, fire retardants, blowing agents, pigments, plasticizers), according to the required specifications provided by the customer. Since the molecular weights of waste plastics resins to be recycled are variable, some blending with virgin resins will be necessary to adjust the Melt Flow Index (or any other property) to meet the desired specifications. Obviously, the design of such a highly complicated for- mulation requires a highly skilled individual. Some analyt- ical services may also be necessary to resolve especially difficult cases, further adding to the expense of handling recycled materials. The unpredictable nature of materials to be recycled may require more frequent servicing and repair of machinery due to scratches, abrasion, and corrosion, thereby increasing production time and costs. When all these extra functions are added together it is sometimes more economical to employ virgin resins. A list of commercial compounders including addresses and phone/fax numbers may be found in the Modem Plastics Encyclopedia [5].

The obvious market for large-scale recycling of mixed plastics waste is in the outdoor lumber market. One example of this application is Trimax, a glass fibre- reinforced plastic lumber manufactured by Polymerix [18] In order to accomplish this objective, Polymerix needed to satisfy several criteria:

a) the incompatibility of commingled waste and the resulting low strength which had to be overcome at low cost;

b) the wood replacement product needed to be designed for use with standard wood working tools, nails and other fasteners;

c) the use of an economical process (continuous extrusion, which permits a high production rate ) for the production of plastic lumber profiles having large cross-sections and long lengths (which are areas where treated wood becomes disproportionately expansive).

Studies at the University of Toronto have shown that wood fibres may be substituted for glass fibres without sacrificing performance [17]. The wood fibres may be recovered from waste paper. Wood fibres are non- abrasive, non-toxic, lower density and less costly compared to glass fibres. The Superwood recycling process developed by Lankhorst Touwfabrieken B.V. in Holland is another example of the conversion of consumer waste into synthetic lumber which may be used for pallet boards (skids), benches, curb stops, fences, and picnic tables. This process has been licensed to Superwood Ontario Limited [20].

3.3 Injection Moulding The function of the injection moulding machine is to plas- ticize a portion of the resin feed and inject it into the mould cavity where it slowly solidifies. After a few seconds the solidified part can be ejected and the cycle is then repeated. Since foreign material can damage the screw it is important to ensure the feed is uncontaminated. Most modern machines are fully instru- mented so that the machine may be programmed to dis- card any part that is abnormal, Le., the pressure cycle is outside set limits. The rejects can subsequently be examined for imperfections. The choice of cold runner, hot runner, or valve gated moulds will depend upon the general incidences of failure due to random variations in the feed quality. In general, large gates are more forgiving and might therefore be preferred. The screw might also be designed to provide some mixing in order to com- pensate for incomplete mixing in the resin compound. To maintain variability above the minimum specifications, it is sometimes desirable to increase the molecular weight of the resin. This entails greater viscosrty and slower injection rates which will tend to increase manufacturing costs.

Injection moulding is normally favoured for smaller, complex parts in high volumes, since it is one of the most expensive methods of fabrication. In order to be competitive, these machines are designed to operate unattended 24 hours a day, for months, without servicing. It is now possible to injection-mould parts having a core reclaim material and a skin of virgin material (co- injection). The added complexity of the process is com- pensated by reduced material cost. By such methods, the exterior finish may be textured and coloured to meet marketing requirements. The quality and colour of the core material are invisible to the consumer.

For larger parts, the opportunity exists to produce hollow sections (gas assist) or structural foams. These cost-

10 MAT-92-11

saving features place the maximum material near the surface where it contributes mostly to the exterior of the manufactured parts with decorative finishes (coloured, metallized, textured or wood grain). Various paints may also be applied but it is usually necessary to oxidize the surface so the paint will wet and adhere to the surface. Such oxidative surface treatments include corona, plas- ma, and flame methods. The veneers are especially important for reclaim resins since moulded parts are often black, brown, or of unpredictable colour. Such post treatments can add to the cost compared to virgin resins with pigment coloration.

Structural foams may be reinforced with wood fibres to provide wood substitutes for furniture components. Most conventional injection moulding machines may be simply modified with an accumulator for conversion to foam injection moulding. Ground wood or waste paper may be used effectively for this purpose using a Gelimat mixer with a polar wax as a dispersing agent. Chemical blowing agents may be used to control the core density. Wood fibre composites from waste materials are the lowest cost composites available with specific properties greater than most other materials, including short glass fibre- reinforced plastics. This combination of lowest cost and highest performance makes wood fibre composites (WFC) the first choice for many such applications.

For further information on injection moulding machines and post processing techniques consult the Modern Plastics Encyclopedia [5].

3.4 Extrusion Extrusion is probably the most common manufacturing process for thermoplastics: it is also the least expensive. Extrusion is used to manufacture pipe, sheet and film, profiles, hollow sections @low moulding) and plastics bottles. It is also used to laminate paper and apply insu- lation to electrical wire. Reclaim extrusion may require special equipment in order to accommodate the variable nature of the feedstock. The hopper and the screw may be enlarged at the feed section to accept low bulk density materials and to increase production rates.

Foam extrusion is a particularly effective method to con- serve material without sacrificing performance. The ex- trudate has a solid skin with a foam core. Such products are finding application as a wood substitute in transportation (noise barriers, planks, railway ties, sign posts, traffic barriers, erosion control, retainer walls), housing (door and window frames, fascia, trim, baseboards), ag- ricultural products (fencing, animal pens, gates, tree guards), marine applications (boat docks, sea walls, board walks), recreational (flower pots, park benches, picnic tables, stadium seating, storage bins), gardening, industrial, and civil engineering products. The potential market for such products is estimated at 20 million tons per year. Since most reclaim polymers contain contaminants, a continuous screen changer with a breaker plate is a ne- cessity. Solid state screen changers employ the head pressure to automatically move the screen past a sta-

tionary breaker plate. Multiple extruders may be employed to produce extruded profiles having several layers in which the reclaim material may be interposed between virgin polymers. The greater complexity and cost of multilayer extrusion may be partially offset by reclaim material cost saving.

A typical extrusion line is not complete without several accessories such as microprocessor control, automatic hopper feed system, drier, vacuum sizer, puller, travelling cut-off saw, granulator, dry solids mixer, materials handling equipment, vacuum cooling tank, water cooling tank, and a coiler or stacking device. Thus an extrusion line represents a major integrated production system, capable of processing as much as 10,000 kgh with a minimal labour component.

3.5 Rotational Moulding Rotational moulding is a process for producing hollow, seamless products of various sizes and shapes; it com- plements the processes of injection moulding and blow moulding. Because the process does not involve pressure or precise metering of resins, the moulds and machinery are relatively inexpensive and long lasting. lt is particularly useful for the manufacture of large containers such as storage and feed tanks, shipping containers, trash containers, whirlpool tubs, recreational boats, ca- noes, camper tops, fuel tanks, small swimming pools, construction barriers, septic tanks, portable toilets and shelters.

This manufacturing process permits the successive introduction of resins into the rotational mould so that virgin resins may be applied for the inner and outer skin and reserve the core for reclaim polymers of variable composition. The outer skin may be selected for colour, weather resistance, underground storage, scratch resistance and toughness in order to maintain premium perfomance. Very large containers (20,000 L) may be manufactured by this relatively simple low-cost process.

‘ A major disadvantage of this process is the requirement of a powder grade resin which must be produced by grinding, and most often, cryogenic grinding. This tends to increase the cost of the raw material.

However, this disadvantage is offset by unlimited design freedom; low capital costs: low tooling costs; multilayer construction: minimal scrap loss; the possibility of double walled designs and complex parts; the ability to mould multiple products and multiple colours at the same time; and the process can be geared to mass production. It would be of interest to develop a continuous process for rotationally moulding hollow posts using an open ended cylinder. This should not be difficult. Fibrous reinforcements may be incorporated for added strength and stiffness.

3.6 Calendering The typical 4-roll calender is a form of extrusion with driven rotating slit die lips (rolls). The co-operating four rolls form three nips; the first a work roll controlling the feed rate, the second a metering roll, and the last a final sheet

MAT-92-1 1 11 R d v D - w formation, gauging and finishing pass. Heavy sheeting can run at high speeds (1 to 2 m/s) producing as much as 4000 kg/h. The main disadvantages of calendering are substantial investment costs and lengthy heat-up times. The advantages that make the calender ultimately the most desirable method are:

maximum rates of production accuracy of gauge ease of automatic gauging and control speed of gauge adjustment processing and product range versatility low resin costs high on-stream time factors fast on-line time

Typical applications include lighting fixtures, ceiling tiles, wood grain, signs, tank linings, corrosion-resistant duct- ing, strapping, trays, helmets, luggage, roofing, and pond liners. Although modem calenders are more efficient than those of 30 years ago, it is sometimes more economical to upgrade an older machine. Payback is often one or two years. Note that an extruder feeds the calender rolls. Thus the calendered sheet may consist of laminates in which the mid-layer is reclaim. The food packaging industry is very dependent upon calendered sheet for making plastic containers. These calendered sheets may be thermoformed at high speeds to produce 60,000 mar- garine tubs or several million cream cups per hour. The calendering process for plastics is the equivalent of a roll- ing mill for the production of sheet metal. It is not known whether any experimental calenders exist in Canada.

3.7 Blow Moulding Extrusion blow moulding is an extrusion process using a die head, press, and mould to produce hollow articles [21] The process is used to produce small parts such as bottles and large parts such as 2000 L containers. In this process, the following sequence is performed : a) melting the plastics: b) forming the parison (a round hollow tube of molten

plastics); c) clamping the mould halves in the mould cavity with

high pressure and exhausting the air from the part, opening the mould halves and ejecting the part.

Intermittent blow moulders with accumulators are preferred for larger parts which can process 10 tonnes of resin per hour. Coextrusion of multiple layer parisons permits reclaim resins to be employed in the mid-layers where it is not visible. For smaller parts, injection blow moulding may be employed. These machines permit multilayer construction in which 5 or 6 layers are common. In some processes, a small parison is first injection- moulded and then subsequently stretch-formed biaxially in order to reduce weight and increase clarity and drop impact resistance. This process is particularly useful for polyethylene terephthalate (PETj, polyvinyl chloride (PVC), polypropylene (PP), and polymethacrylonitrile (PMAN). The widespread use of plastics bottles and containers for non-food items makes this a prime market for reclaim polymers.

3.8 Compression Moulding Compression moulding pertains primarily to thermosetting compounds, including rubber. The advantages of this system include simplicity and economy of operation. The process may be automated so that as many as 50 machines may operate on a conveyor line with one operator. Tooling costs are low because of the simplicity of the moulds. Little material is wasted since there are nc; sprues, culls, or runners. High concentrations of fillers and fibrous reinforcements may be incorporated without difficulty. Larger parts may be produced with less clamping force, thereby reducing capital costs. There are few applications which employ thermoplastic resins since injection moulding is largely preferred. However, it is quite feasible to compression-mould thermoplastic batches into finished products if desired. This is particularly ad- vantageous for highly filled compounds that cannot be processed by ordinary means. Experiments at the Uni- versity of Toronto have shown that thermoplastic composites containing more than 80% filler (mica, wood fibre, paper, ground wood) may be directly compression- moulded after discharge from a Gelimet Mixer. The heat- ed compound is allowed to solidify in the chilled mould after compression. Thus compression moulding usefully extends the range of compositions which can be con- verted into finished products.

Many of the products made using virgin or recycled rubber are produced via compression moulding. Since rubber is a thermosetting material, curing or vulcanization extends the time the product must stay in the mould. For products using recycled rubber crumb, binding agents (typically polyurethanes) must also be cured. The length of curing time increases markedly for products of large cross-section, becoming an important constraint on production rates and thus on product economics. Novel heating techniques such as microwave heating are being considered to alleviate this problem. The problem can be avoided in part by using lower density foamed products where feasible, as they have lower mass and thus reduced heating and curing times.

4. Assessment of Candidate Products 4.1 Overview of MTO Material

and Product Categories The MTO is a major user of materials for the construction and maintenance of highways and related structures.

Currently, the non-pavement-related uses include the following materials :

concrete composites steel slag aluminum straw wood rubber plastics

These materials are used in applications ar;d/or structures such as the following:

e d v D d w 12 MAT-92-11

~~ ~

Item Description Quanti in inventory

picnic tables plywood signs concrete culverts C.S.P. and structural plate culverts timber culverts access hatches and catchbasins luminaires delineators small metal signs aluminum signs guiderail posts inertial barrier modules elements of steel beam guiderail posts of box beam guiderail snow fence concrete barriers highway fence noise/privacy barriers

While plastics are already used for some items on this list (e.g., in delineatordtraffic cones and snow fencing), the material used is generally virgin resin. A more comprehensive list of the MTO highway products inventory is given in Table 5 [22] for the year 1991.

The records for 1989, 1990 and 1991 in the maintenance management section of MTO indicated that the inventory figures have not changed significantly over this period. For that reason, the actual numbers replaced are also shown in Table 5 to provide a better estimate of the potential number of units consumed. This, in turn, when combined with estimates of product weight, can be used to estimate the quantity of recycled plastics or rubber that potentially could be consumed. Not every product on these lists is considered to be a candidate product. Three criteria were used to select products for more detailed examination.

The first simply looked at the number of units replaced annually to determine whether MTO's switching to a product made from recycled plastics or rubber would have a significant impact on the disposition of these materials. This did, however, take into account the fact that MTO acts in many cases as a purchasing leader and can influence other market.

The second criterion was the likelihood that the technology exists to produce an alternative product made from recycled rubber or plastics. This took into account the performance and safety requirements for the product. The third criterion was the estimated cost competi- tiveness of the recycled material product, attempting to take full cost-benefit factors into account.

Based on the foregoing criteria, it was decided to divide the resultant products chosen into two groups. The first group comprised those products deemed likely to have the greatest potential to significantly impact the use of recycled plastics and rubber. In some cases, these products were then grouped into logical clusters where, for examde. one technoloav miaht serve to make several

~

No. replaced in 1991 1

products. Members of this group are examined in some detail in Section 5.1. The remaining products are examined in less detail in Section 5.2.

4.2 Economic Viability The probable price and economic viability of candidate products for highway applications will depend on several factors. First among these is the cost of feedstock resins. Prices for virgin resins are determined by world markets. Scrap (as opposed to recycled) plastics are generally val- ued at 20% or less of the virgin resin price. Recent issues of Plastic Recycling Update and of Plastic News (Oc- tober, 1991) [23,24] were consulted for recycled plastics

Table 5 Provincial highway inventoiy of products (1991)

1 2 3 4 5 6 7 8 9 10

12 13 14 15

16 .:. 17

18 19 20 2l 22

n

Bridges 2640 Concrete Culverts 12,200 CIP & Structural Plate Culverts 134,000 Timber Culverts 1470 Access Hatches & Catchbasins 65,000 Flashing Beacons 662 Luminaires 26,000 Delineators 85,000 Small Metal Signs (m 2) 71,400 Plywood Signs (m2) 71,900 Extnrded Aluminum Signs (m2) 53,400 Guiderail Posts 881,000 Inertial Barrier Modules 7092 Elements of Steel Beam 369,000 Guiderail Posts of Box Beam Guiderail 106,000 Snow Fence (m) 149,000 New Jersey Barriers (m) 239,000 Farm Fence (m) 3,080,000 Secunty Fence (m) 679,000

Wood Sign Post 4"x4", 6"X6", 6x8' in cross section and 1O'to 16 in lenath

NoisePrivacy Barriers (m) 91,900

19,1942 92463

10,3203

29,553a 306

3006b 1236c 3009 4002 50

8364 2860 991 4

14,763d

"

1

2

3

a

b

C

d

Quant i placed/replaced are from MTO Maintenance Operation Record (MOR) for 1991 (Feb.l4,1992). Combined total from MORfor 1991 and MTO Report 14 for 1991.

MTO Materials Usage Report for 1991

Number of untreated cedar round posts from MOR 1991.

Number of treated 8X8X7' guide rail posts (red or jack pine) from Purchase Records. Number of treated 8"X6'X24"/8'X8"X16' block (red or jack pine) from Purchase Records. Number of treated 4X4'/6"X6"/6X8" sign posts (red or jack Dine) from Purchase Records.

I MAT-92-11 13 R d V D W W

resin prices. The findings are summarized in Table 6. These recycled resin prices reflect the costs of collection, cleaning, and reprocessing. The price range for different mesh sizes of rubber crumb derived from scrap tires (outlined in Section 3.3) varies from 13~ /kg up to 44c/kg, depending on particle size, narrowness of size distribution, and the technology used to generate the crumb.

Two recent reports in Ontario dealt with the availability of commercial/industriaI and post-consumer mixed plastics feedstock. The first study (prepared by Proctor and Red- fern Ltd. for EPIC and MOE, July 1990) [7] examined the feasibility of operating a separation and recycling facility for mixed rigid plastics containers. The study’s economic evaluation concluded that the cost to sort, process, and handle mixed plastics generally exceeded their values unless the various plastic resins are refined and processed to end products of high value. The second report, published by MOE in December 1990, dealt with a com- merciaMndustrial waste plastics feedstock procurement and sensitivity analysis for a mixed plastics recycling facility [4]. The supply survey has established the existence of large quantities (about 4600 tonnes) of waste plastics which are currently not being recycled in the Greater Me- tro Toronto region. This material, consisting mainly of polyolefins, is generally unattractive to companies involved in plastics regrinding because it contains mixtures of resins or is contaminated. This material was estimated to be available for recycling at a target cost of 11 ckg.

A production cost analysis for a commerciaMndustria1 waste plastics recycling facility (conducted for MOE by Proctor and Redfern Ltd. 1990) revealed that variable costs for a basic product would run at approximately 47c/kg (Table 7). In addition to the variable costs, fixed manufacturing costs, primarily equipment depreciation and rent, will range from 26 to 77c/kg (12 to 35c/lb), de-

.

Table 6 Recent prices for recycled plastics resin feedstock (CAN$/@)

Information Source ~~

Plastic News Plastic M 0 E Recycling

Resin Type (Clean (Pellets) (Regrind) (Pellets) Grind)

High-densty 52-57 98-106 45-55 98-108 Polyethylene (HDPE) Post-consumer

Industrial 44-52 96-105 40-50 95-105 Polypropylene (PP) 30-40 - - 35-70 Industrial

Industrial Polystyrene (PS) 47-57 98 67 102

Polyvinyl Chloride 29-49 - 44 55 (PVC) Industrial

pending upon the number of shifts the equipment is kept running (Table 7).

This will be driven primarily by the amount of manufactured product that can be sold (e.g., plastic lumber). Fixed manufacturing costs would be somewhat lower for a processing plant with multiple extruders because rental costs, storage areas, and some other equipment costs do not increase proportionately with each additional machine.

In addition to the manufacturing overheads, there are general administrative and sales. overheads. These are even more sensitive to the scale of operation, being relatively constant until quite large volumes of production are reached from three or more machines. An ex-factory price for the basic product is expected to be between 88c and $1.10 per kilogram (40 to 50cAb). On this basis, the finished product price would rise by 5% to 6.5% for a 50% rise in raw material price above the assumed 11 Q/ kg. It is m t clear how price-sensitive the proposed product markets will be. Already, the product would be at a substantially higher price compared to pressure-treated pine, or other materials with which it will mostly likely be competing.

It is apparent from the prices listed in Table 6 that the costs of collection, sorting, cleaning, and reprocessing keep their levels relatively high. However, two approaches may moderate the probable price of the waste plasticdrubber-based products for highway applications. First, the cost of sorting may be eliminated since the fledgling plastic lumber industry is capable of processing commingled plastics. Second, the incorporation of wood fibre andor wood flour (also from the waste stream) into commingled plastics composites may reduce material costs by 50-60% [25] The technology and scientific

Table 7 Estimate for waste plastics recyclng

Cents

Variable Costs, Basic Product per kg. per Ib.

Waste Plastics Materials 11.0 5.0

Labour 12.1 5.5

Utilities, Maintenance 4.4 2.0

Other Materials 8.8 4.0

Sales Commissions 5.5 2.5

Rovalties 5.5 2.5 ~

Total ~

47.3 21.5

Fixed Manufacturing Costs Cents

One shift per machine 77.0 35.0

Two shifts per machine 39.6 18.0

Three shifts per machine 26.4 12.0

Source: MOE (Proctor & Redfern, [7])

R d V D U W 14 MAT-92-11

know-how is available to add and mix as much as 50% wood fibre to commingled thermoplastics [17]. The input cost of wood fibre is estimated in the range of 8 to 126/ kg. Thus, in a 2:l (plastics-to-wood) ratio material costs may be reduced from 406kg to 30I$/kg, or in a 1:l ratio from 406kg to 25ckg. Another advantage of using wood fibre-plastics composites for highway products is that most of the engineering properties of plastics are also improved. This is especially true of the flexural strength and modulus.

During the consultative process with officials of MOE and several wood waste recycling firms it was determined that there is an annual quantity of over 250,000 tonnes of readily-available wood waste in the greater Metropolitan Toronto area. Over half of this material is currently un- used. Thus, prospective manufacturers of wood fibre containing plastic lumber would be able to utilize this supply. Waste plasticshmber-based products (especially wood- plastics composite lumber) may also be manufactured in or near regional centres of the Province (e.g., Windsor, London, Kingston, St. Catharines, Sault Ste. Marie, Ot- tawa, Timmins, Thunder Bay), provided sufficient quantities of waste plastics are available. Many of the existing processors of scrap plastics who were interviewed showed a surprising lack of sensitivity to the local availability of feedstocks - perhaps because they can so easily import material from distant sources, then process the material and market the reprocessed plastics by shipping over considerable distances. The processors interviewed were, however, all based in southern Ontario, and it is likely that northern based operators would still benefit strongly from local waste feedstocks, such as, for example, that derived from a blue box separator process.

The preceding paragraphs take a classic costing approach by referring to the price of raw materials alone - only one element of the true cost of a product (261 Particularly when the environmental benefits of a product are being considered, it is imperative to at least attempt to take a more encompassing view of product costs. This is perhaps best done from a life-cycle approach - either as life-cycle costing or as life-cycle value [27]. In either case, the true costs of a product must reflect:

cost of sourcing the product, cost of storing, cost of installation, I

cost of maintenance, cost of disposal.

In each case it is important to ensure that all costs - both hidden and directly incurred - are accounted for. This is particularly relevant for disposal costs, insofar as many disposal costs are hidden to the direct disposer, but they are very significant for society (e.g., landfill costs). The value, or potential value, for recycling must also be factored in since this offsets other direct costs. In addition, factors such as impact on overall road maintenance patterns, and longevity past normal routine replacementhebuild times must be considered.

5. Discussion of Tech n ica I/E con o m ic Viability for Selected Products

5.1 Detailed Reviews

5.1.1 Dimensional Lumber Substitutes

Recycling of commingled plastics is often associated with “plastic lumber” [17,18, 25, 28, 29, 301 . The principal advantage is that no sorting or cleaning of waste plastics is required for the production of plastic lumber. Advanced Recycling Technology of Belgium is one supplier of plastics lumber manufacturing equipment. Their equipment is sold under the trade name €T-1 SystemTM. The key steps in the process are:

COLLECTING

1

i MTRUSION

i COOLING

The ET-7 System is based on a type of compression screw extrusion into a steel mould. The extruder is specifically designed to maximize melting and minimize degradation of polymers so it can be used to process a wide range of plastics. A short adiabatic screw rotating at high speed is used for melting. The short melt cycle prevents degradation of sensitive resins and the high speed permits thorough mixing of recycled materials. The extruder stops after filling each mould and starts only when another empty mould is positioned for filling. Melt temperatures of 360°F to 400°F are regulated by a cooling fan, water circulation lines, RPM adjustment, or by adjustment of the tolerance between the extruder screw and the barrel. Plastics such as PFT and polycarbonate, which melt at high temperatures and metals such as copper and aluminum fragments, become encapsulated in the metted plastics and such materials if used in the proper ratio, act as fillers that enhance specific properties Such as modulus.

The moulding unit consists of a linear mould mounted on a turret that rotates through a water cooling tank. The moulds are interchangeable, so they can be used to meet specific production requirements. Inexpensive custom moulds can be built using standard seamless steel shapes. Shrinkage of the parts as they cool in the mould permits air ejection from the open end of the mould. The pneumatics of the 0 - 7 System require a 10 MPa (140- psi) compressor with a 4000 L (100 gal) tank. Following ejection, the part is delivered into a receiver and then dis-

MAT-92-1 1 15 R d v D - w charged onto an open shelf for manual removal. The part must be completely cooled on a rack made of continuous slotted angle iron to prevent warping or deformation.

The ET-7 System is designated to run 100% post- consumer waste plastics. Rigid plastics must be ground into 0.25 inch chips or flakes. Flexural plastics, film or thin sheets must be densified into small granules to maintain friction in the extruder. The regrind and granules are blended to ensure an even dry mixture of feedstock. Dur- ing the blending, plastics modifiers, additives, colorants, or virgin feedstock may be added. The blended feedstock is automatically conveyed as needed by an auger to the extruder hopper.

The ET-7 recycler’s patented short adiabatic extruder screw was designed to handle as wide a variety of materials as possible. In principle, the machine will handle any thermoplastic resin, but there are technical limitations im- posed by the processing and physical properties of the available parts. The principal handicaps of the FT-7 Sys- tem are a relatively long cycle time and slow production rates. Fabrication of complex shapes and long lengths are also problematical. A more recent development is a continuous extrusion process introduced by TRIMAX Plastic Lumber, a sub- sidiary of Polymerix Inc. (Ronkonkoma, New York) [30]. With this system, higher throughputs, large cross- sectional shapes [up to 30 cm (12”) width], and lengths up to 11 m (36 ft) are possible. Also, the continuous extrusion concept is more suitable for foaming the finished product. This would allow density reduction and more efficient material usage.

One of the concerns with plastic lumber (even for non- structural highway applications) is the adequacy of certain strength properties. Of course, the concept of “non- structural” is not a rigid definition as most non-structural uses involve certain loads and stresses. For example, picnic tables and benches must support the weight of persons; sign posts and sign blanks must withstand wind loads; guiderail components may have to withstand severe impact loads. Table 8 lists the physical and mechan-

ical properlies of four commercially-produced plastic lumber products compared to two species of (clear) wood.

While plastic lumber has, in general, a good balance of mechanical properties, it is significantly weaker than wood in flexural modulus. This also implies that long-term deformation under load (i.e., creep) is also a problem. In fact, one manufacturer reported that glass fibre reinforcing is being tried to reduce creep [30]. The same manufacturer indicated they are conducting long-term field tests under extreme outdoor conditions in Florida and Arizona.

Another U.S. manufacturer of plastic lumber indicated their product is not recommended for any structural application. However, we feel confident that in low-stress applications (such as picnic tables and benches, fence and small dimension sign posts/sign blanks) plastic lumber will prove to be more than adequate.

One low-cost way to enhance the strength properties of plastic lumber is to add wood fibres as a reinforcing filler. Research and development work at the University of To- ronto (Tables 9 and 10) and elsewhere confirmed that significant gains in strength result from the incorporation of wood fibres. Currently only one U.S. manufacturer is producing such a product. Technical information about the product properties could not be obtained from the manufacturer; therefore it was not included in Table 8.

Differences between the properties of the four commercial plastic lumber products are relatively minor (with the exception of the tensile strength of product B, and the flexural modulus of product C). The main plastic resins in all four products was a type of recycled polyethylene. All four products are “mildly” foamed (as indicated by their densities). Proprietary information about process or product was neither solicited nor provided.

There is a general lack of information about mechanical properties of waste plastics-based products under elevated (35 to 40°C) and low temperatures (-35 to -45°C). Similarly, the repeated recyclability and the possibie

Table 8 Physiical and mechanical properties of several commercially-produced plastic lumber products and two wood species [Source: Survey]

~~ ~ ~~

Property Product A Product B Product C Product D White Spruce Jack Pine

Denslty (g/cm3) 0.70 0.78 0.70 0.75 0.40 0.44 Tensile Strength (MPa) 9.9 24.1 8.6 9.0 89.6 102.0

Flexural Strength (MPa) 19.3 20.7 20.7 15.9 67.6 77.9 Flexural modulus (GPa) 0.9 11 3.1 1 .o 9.2 10.2

Compressive Strength (MPa) Parallel 20.7 22.1 121 19.7 37.7 40.5 Perpendicular 3.2 5.7

Note: The main material of composition for products A, B, C, and D is recycled post- consumer polyethylene. Product A contains approximately 15% waste paper fibre.

16 MAT-92-1 1 R d V D + W leaching of residual contaminants (if any) have not been reported on. These issues may be addressed in future by MTO, perhaps under its Joint Transportation Research Programme.

5.1.2 Noise Barriers Noise barriers are walls designed to attenuate noise from roadways. Such walls often serve a secondary purpose of providing privacy screening. In 1991 MTO maintained over 91 km of noise/privacy walls: of this, about 10 km was installed since 1989 [22]. Historically, such walls have been made from steel, concrete or cellulose- modified concrete products [31].

The primary safety concems about noise barriers are two-fold. Firstly, does the product have long-term structural integrity, particularly following exposure to salt spray and freezehhaw cycles? Secondly, in the event of a calli-

~ ~~

sion, does the product demonstrate sufficient resistance to fire and resistance to fragmentation?

Coupled to these are the usual concerns of cost ef- ficiency and efficacy - does the barrier provide the req- uisite attenuation of noise?

Recently, a new design has been proposed for noise barriers that utilizes recycled tire crumb rubber in its manufacture [32]. This design is based on crumb rubber moulded around some form of reinforcing stiffener introduced to give greater rigidity to the rubber panels. This reinforcing has been prototyped as either wood or metal. While the panels appear to perform adequately in noise attenuation tests, they have not passed the existing fire attenuation tests. Two interpretations have been put on this latter observation - one, that the material is unacceptable; and two, that the test is invalid for this material. While it is obviously true that a rubber product will

Table 9 Properties of experimentally-produced waste newsprint (NP) fibre-reinforced polyethylene (PE) and polypropylene (PP) composites at 25% fibre content [17]

Property Composite Typea

A B C D

Density (s/cm3) 0.98 1.00 0.90 1 .oo

Flexural Strength (MPa) 13.0 26.4 57.4 74.8

lzod Impact (notched, J/m) 403 46 30 19.1 Impact (unnotched, J/m) 507 198 241 153

Tensile Strength (MPa) 8.6 16.2 31.7 41.5

Flexural Modulus (GPa) 0.2 0.75 2.2 2.9

Mett Flow Index (g/lO min) 46.8 3.7 10 2.6

a A: 100% PE C: 100% PP

B: 7O0/oPE t 25% NP + 5% C16 D: 7O’hPP + 25%. NP + 5% E43

No break

Table 10 Properties of experimentally-produced waste newsprint -polypropylene composites [17]

Property Wood Fibre Content (%)

0 20 20 30 40 50 Density (s/cm3) 0.88 0.95 0.98 1.00 1.04 1.07

Tensile Strength at Yield (MPa) 31.6 32.4 37.6 44.6 50.8 46.9 Elongation at Break (%) - 9.1 5.4 4.4 3.4 2.3

Flexural Strength (MPa) 49.1 54.5 64.9 74.9 83.3 80.0 flexural Modulus (GPa) 1.3 1.6 2.2 3.1 3.9 4.8 Notched lzod Impact (J/m) 15 18 17 14 15 16 Unnotched lzod Impact (J/m) 787 223 173 138 125 81

Melt Row Index (NO min) 13.9 10.1 3.9 1.8 0.7 0.2 Heat Deflection Temperature 87 114 137 148 150 152 (HDT ) 455 kPa (“C)

show greater flammability than a comparable steel or cement product, it is less obvious just what constitutes an acceptable level of flammability. Pro- ponents of the new system argue that the flame spread and smoke development data meas- ured indicate different, rather than utiacceptable behaviour. Since the flame spread is considerably less than for the red oak reference standard, it is the smoke generation that gives rise to concerns. The rubber product shows a longer induction period before the onset of smoke generation, followed by a sharp increase that tails down to below the reference level. The integrated total is some 28% higher than the reference, considered to be the maximum permitted. The level of fire retardant added will, of course, influence these results strongly.

While interpretation of the safety data is perhaps uncertain, an eqlially important consideration is the economic viability. Current price estimates for installed crumb rubber-based systems vary from $1 45/m2 (supplier stated) to $190/m* (MTO

MAT-92-11 17 R d % D + W estimated). These compare to the existing cellulose- modified concrete product or steel product, both at $12O/m2 (MTO estimated). It is clear that the price for a crumb rubber system also depends critically on the tipping fee charged for disposing of the tires. At the costs given above, it is estimated the crumb rubber products would require a $90/tonne tipping fee for a break-even business. This should be compared to current landfill costs in southern Ontario which are in the $12O/t to $15O/t range (in northern Ontario $20/t is typical). This should also be compared to the current tire tax of $5 on each new tire, or roughly $550/t if each tire is assumed to produce 9 kg of waste. It is not clear what factors should be included in an accurate comparison of the crumb rubber-based system compared to the conventional. In general, the higher the value placed on disposing of tires, the more cost-competitive the new technology will be.

5.1.3 Traffic Delineators and Barriers

Traffic barriers Traffic barriers, such as a New Jersey barrier, must be capable of passing crash tests that demonstrate an abil- rty to deflect colliding vehicles away tom the barrier (and from what is generally oncoming traffic on the other side of the barrier) [33]. They must do this while not disintegrating into debris that could hit vehicles and without posing a flammability risk should there be sparks or a fire during the collision. Permanent barriers: In 1991, MTO had an inventory of over 238 km of New Jersey barriers [22]. At an estimated 200-300 kg/m, if these were made of solid recycled plastics or rubber there would appear to be significant potential for the use of recycled material. However, a number of serious problems would have to be overcome before this potential could be realized. There are several reports of barriers that have been made out of plastics, although it appears that none of these have yet used recycled plastics. These barriers have the inverted T-form of a New Jersey barrier, but they are hollow and are intended to be filled with either sand or water. A number of safety concerns exist with this design, particularly when using water. If the unit springs a leak (due to repeated freezdthaw cycles or due to a minor collision), it will lose most of its impact-absorbing properties - but it may not be evident it has done so. Hollow units have the advantage of portability when empty, but only water filling represents an easier process than transporting a pre- formed concrete barrier.

Cost factors have dictated that permanent traffic barriers be made of conventional low-cost road construction materials such as concrete. lt is unlikely that solid plastics or rubber units will be able to compete with concrete on a cost basis, at least with the cycle times possible using current technology for the moulding or casting of large cross-section pieces. Perhaps the most compelling cost argument against the easy introduction of a recycled plastics permanent barrier comes from the testing requirements. Field tests demonstrating maintenance of barrier integrity and complete vehicle deflection following

collisions with vehicles such as semi-trailer trucks [33] are required in most jurisdictions. The prohibitive cost of these tests suggests that it is unlikely any manufacturer will come forward with a plastics permanent barrier that is subject to any degree of uncertainty in its manufacture. Since, as has been discussed in Chapter 3, the use of recycled materials conveys a degree of uncertainty higher than for virgin (and since there is little price incentive for the use of recycled materials) we see little likelihood of a permanent barrier made from solid recycled plastics ap- pearing on the market. Temporary barriers: The above-described hollow plastics New Jersey type barriers may be used as temporary barriers and as such are not subject to the same con- straints as permanent barriers. Concerns about leakage, of either water or sand, are not as severe if the intended use is of short duration, although safety concerns remain paramount. Ease of installation is more important, and the light weight of a hollow unit is attractive. However, even the hollow units represent a substantial mass to be moulded or cast. It is unlikely that any producer would use a recycled resin unless this conveyed a significant price advantage. This is particularly important for large units with slow production times, since raw material costs are likely to be a smaller fraction of total costs than for some of the smaller items considered below.

Traffic delineators The term “traffic delineators” is used here to describe a fairly wide range of products that provide either permanent or temporary traffic control by means of lane delin- eation. The distinction between permanent and temporary is very important, particularly since the safety requirements for traffic delineators are quite stringent.

Short-term traffic delineators (e.g., traffic cones, metallic delineators, channelizers, barricades, and raised pavement markers) are not expected to deflect vehicles colliding with them. This often engenders a more strict requirement that the delineator should not disintegrate, ’

since they are often used around occupied construction sites etc. where flying debris could pose a serious threat.

In terms of performance, again there are differences in the requirements for permanent vs. non-permanent structures. For permanent structures, durability over an extended time throughout all seasons is obviously key. Ease of installation is important, but less so than for temporary barriers and delineators since permanent barriers are installed only once over a long period of time, often in conjunction with other road work. Because of their use in short-term situations, temporary delineators have a higher visibility requirement, which is generally satisfied by the use of bright colours and reflective tape or sheeting.

Temporary delineators have been made from a variety of materials such as wood, steel, and different plastics or rubber. It should be noted that temporary delineators are often associated with the use of sandbags to anchor them in place - again, the lowest cost way of adding weight to otherwise lightweight, easily-transportable items.

R d % D * U 18 MAT-92-1 1

In 1991 MTO maintained over 85,000 delineators ([22]. These comprised a variety of different types. One of the best known, though not in the inventory, is the ubiquitous traffic cone, which is generally made of a PE or PVC cone supported by a rubber base. It is currently available with a base made from recycled rubber [34, 351. There exists no good technical reason that the cones could also not have a significant recycled content. Perhaps the greatest current limitation is the availability of recycled low-density PE or PVC suitable for these moulding applications. Other delineator designs have been produced from recycled materials. The State of Illinois, in conjunction with a major resin producer, has field tested, satisfactorily, a barricade made from recycled milk containers (HDPE) [36]. The unit is manufactured in the shape of an upright panel on support feet. An altemative, in the form of an A-frame barricade design made using recycled high-density polyethylene (HDPE) is also on the market [35]. The first of these two examples is made from 100% recycled material; the second is unspecified as to percentage recycled.

Other designs such as barrels or posts exist; since they are currently made of plastics, they too could have a recycled resin content, within the limits of availability of recycled resin of suitable grade. For these units, and particularly for the more complex barrel shapes, other factors come into play: if the existing moulds do not perform well with the available grades of recycled resin, then the recycled content will be limited until such time as the costs of new moulds can be warranted. This could either be in the normal course of replacing wom-out moulds or with some incentive provided by purchasing agencies.

One final point which must be made about delineators concems to the sandbags mentioned earlier. Although sand probably represents one of the lowest cost sources of weight, consideration should be given to moulded rubber rings or blocks that can serve as weights. These would likely cost more than sandbags initially, but their greater convenience and durability would bring their life- cycle cost down to a comparable level. Since they can’t leak, they retain their anchoring properties despite rough handling in use or installation. They could be made from 100% recycled rubber (plus a binding agent) and are comparable to many similar products already made from recycled rubber now on the market [37].

5.1.4 Sign Blanks Sign blanks are sheet materials currently made of aluminum, steel or plywood. The Ministry has a variety of sizes and applications, ranging from relatively small traffic signs on rural or secondary highways to large overhead signs on expressways. Plastics may be formed (via extrusion, calendering or compression moulding) into sheets for sign blanks as discussed in Chapter 3. Most of the advantages and concems presented for plastic lumber also apply to sign blanks. Therefore, it is recommended that MTO should consider field testing recycled plastics sheeting for small size (e.g., 1 x 2 m) sign blanks.

One possible variation of this recommendation is to use plastic sheathing with lower grade plywood or possibly

3

oriented structuralhoard into a type of sandwich panel. In fact, this type of sign blank is available but with thermosets (phenolics) being employed.

5.1.5 Access Hatch / Catchbasin Collars The failure of the pavement surrounding access hatches and catchbasins can be attributed to three factors:

1) the differing expansion rates of the cast iron access hatch vs. the surrounding asphalt leads to crack formation on repeated heating and cooling, particularly in winter.

2) The vibration caused, in particular, by heavy vehicles works on the differing elasticities of the asphalt vs. iron - again causing crack formation.

3) During installation, poor compaction of the soil under the asphalt surrounding the access hatch or catchbasin leads to settling over time and thus failure.

Regardless of the cause, the proposed solution is the same - place a collar made of rubber around the access hatch to act as a shock-absorber ring or gasket to alleviate all three possible causes of failure given above. The collar can be made of 80% recycled rubber, along with 20% polyurethane binder [38]. Each collar would weigh about 150 kg. and would thus use up the rubber from 20 to 25 tires. Given that there are an estimated 500,000 access hatches and catchbasins in Metropolitan Toronto alone, the potential for consumption of scrap rubber is significant. In addition, the risers used to support the hatch, currently made of concrete or bricks, could be made of moulded recycled rubber as well. While not a new product as the collar is, these represent a logical extension of the technology to a different aspect of the same application.

The major safety issue attending introduction of this product would be the potential, for unexpected reasons, for increased cracking of the asphalt and the concomi- tant generation of chunks of asphalt that can be thrown

‘,.up by vehicle tires. While unlikely, because of the totally new nature of the product this cannot be completely ig- nored. The economic viability is likewise anticipated to be extremely good, but remains to be proven. In this case, the unit represents an increased cost during installation (on demonstration trials estimated to be about $600. but expected to be considerably lower in full production applications). This is traded-off against a reduced need for maintenance. Without field trials it is virtually impossible to predict the actual cost savings over time.

Field trials are currently underway, with nearly 100 units installed at the end of 1991. Once a preliminary examination of these trial results is complete, a much better economic viability analysis and technical evaluation can be performed.

5.2 General Reviews While each of the following product categories is treated very briefly, the detailed discussions in the previous section should be used as a guide in their interpretation.

MAT-92-11 19 R d v D - M Picnic tables and benches: Wood is the traditional material in these applications. “Plastic wood” or “plastic lumber” may be easily substituted. In fact, manufacturers of plastic lumber are strongly recommending their products for picnic tables, park benches and landscape timbers. Plastic lumber provides long maintenance-free service. It can be worked with ordinary power tools and traditional fasteners such as screws and nails. One handicap for the substitution of plastic lumber for wood is price. Our in- formal price survey revealed that plastic lumber may be from 50% to 400% more expensive than wood. How- ever, with more manufacturers and the possible incorporation of waste wood fibre in the product the price may come down to a competitive range. Culverts: For relatively large cross-sections plastics would not be suitable. However, for smaller diameter applications (30 to 40 cm) PVC has excellent performance characteristics. It is tough, very durable and self- extinguishing when exposed to fire. Some scrap PVC suitable for culvert type applications may become available from construction wastes or from the recycling of post consumer bottles. Paving bricks: One recently-developed, novel use for recycled rubber crumb and recycled plastics is as components in asphalt paving bricks [39]. These bricks are competitive to the conventional cement paving bricks and are intended by their manufacturers for low-speed road applications - city core streets, parking lots, etc. The bricks are composed of approximately 70% recycled asphalt, 20-25% recycled rubber crumb with the remainder being recycled plastics. Each square metre covered would consume about 15 kg of rubber crumb. They can be installed using the same equipment as conventional paving bricks and are projected to sell at a 10% discount. (Relative prices are: regular asphalt $1.25 to $1.55/m2, asphalt brick, $1.95/m2 and cement brick, $2.25/m2.) Railroad crossing mats: In an application similar to the access hatch transition collars, railway crossing mats have been moulded from recycled rubber crumb [40]. While each mat uses several hundred pounds of rubber (up to 700 pounds), there are generally only a limited number of crossings where use of the mat is considered. Expense of this system has proved to be a barrier, but it has gained some acceptance in the United States. Snow fencing: The MTO has already examined a wide range of different materials used in snow fencing, The report [41] concluded that although adequate performance depended less on material used and more on the geom- etry of the fence, costs differed more based on perceived ease of installation. The products made using recycled plastics while excellent performers, require more staff for installation. Whether this added cost outweighs the benefits of using modest amounts of recycled plastics is not clear. Offset blocks: Another potential application for plastic lumber products (or even for moulded rubber) is for the blocks used to offset guiderails from their support posts. The prime requirement is that the material has to be rigid

(high modulus) for proper deflection of vehicles in crashes. Creep may also be a concern. Rumble stripdspeed bumps: Intermittent raised strips of material laid across a roadway can be used to raise driv- er awareness levels (if the strip is low) or to limit speeds (if the strip is sufficiently high). In either case they could be made from moulded recycled rubber crumb. Since use of either product by MTO is extremely limited this is not seen as a major potential use of recycled rubber. Glare screens: On barrier medians on certain roadways, glare screens are fitted on the barrier to deflect the head- light beams of oncoming traffic. These screens are currently made of a composite that could conceivably be replaced by a moulded rubber product at a cost saving. Care would have to be taken that the strength of the rubber product was adequate. Again, this product would not likely consume any significant volume of rubber. It is included to illustrate some of the smaller creative applications that have been suggested.

6. Conclusions It is difficult to draw many product-specific conclusions from the preceding chapters, since for most products a combination of technical and non-technical factors must be combined to determine the desirability and feasibility of manufacturing from recycled materials. Nonetheless, several more general conclusions can be reached, and from these conclusions, recommendations can be prepared. Our first general conclusion is that there is a plentiful supply of rubber crumb and of some plastic resins that has the potential to provide feedstock for products made from recycled materials. It is important to note the distinction between having the potential to provide the feedstock versus actually currently doing so. For example, as discussed in Chapter 2, the supply of tires in Ontario is clearly sufficient to meet at least most of the projected needs for the products discussed in Chapter 5 (noise barriers, access hatch collars, traffic cone bases etc.). The current crumbing capacity, however, would not meet those same needs, The supply of some plastic resins is likewise limited. High-density polyethylene is collected as milk jugs and is currently in short supply. If blue box systems were to broaden the collection base for HDPE, the supply could be considerably improved. Limitations such as these do not place a technical restraint on the use of recycled materials, but rather a business constraint. With adequate market demand for recycled materials it is most likely that the supply will develop to meet the need. This will necessitate some attention to timing by the Min- istry if it decides to put recycled content requirements into place. Lead times of one to two years may be necessary to allow industry to respond to market demand. Our second general conclusion is that there are no insur- mountable technical barriers to the use of recycled materials, at least in terms of conventional plastics processing. The range of products already on the market made from high percentages of recycled rubber or plastics provides ample proof of this. However, as for the

R d Q D d + S - d B u ; w e 20 MAT-92-11

preceding conclusion, there are issues of timing that are important. As mentioned in Chapter 3, some changes in processing are often necessary to accommodate recycled resins. Changes in mould design etc. all depend on how well the recycled material matches the specifications of virgin material. It may therefore be necessary to allow some time for the introduction of tooling geared to the use of recycled resins. In general, the advantages of using products made from recycled plastics (aside from the obvious environmental ones) will be those that are commonly associated with plastics per se: good durability, good dimensional stability, low maintenance cost (when compared to most metals), and ease of manufacture. The disadvantages will likewise be those associated with rubber or plastics: relatively poor modulus, poor long-term creep performance, potential flammability, cost (when compared to wood or concrete). Our third general conclusion also refers to technical requirements - the specific requirements of MTO. Each product under consideration has its own particular set of MTO requirements with respect to safety, performance, and costing. For many of the applications, few data are available to answer these questions with anything other than an estimate. It is in this area of product-specific performance that we see the greatest need for further work. For example, while plastic lumber exists in many different forms and has been applied to park benches, traffic stops etc. for many years, how relevant is that ex- perience to the use of a comparable plastic lumber product for sign posts? The field performance for such properties as creep under load (e.g., wind load on the sign itself) at different temperatures, shear performance under simulated vehicle impact - these are difficult to predict based upon existing technical data. We conclude that considerable field and back-up laboratory testing is needed to fill these gaps.

Based on these rather general conclusions, we make a number of specific recommendations. These recommendations are divided into two groups - those referring to products already made of plastics or rubber; and those that would entail a switch from a different material to plastics or rubber. The recommendations are as follows:

For non-structural highway products which are already made of plastics, MTO should consider specifying a minimum content of recycled materials (e.g., 50%). The policy should be phased in over a reasonable time to permit manufacturers access to recycled stocks, and to allow the market to respond to the increased demand. This is particularly true if the product involved would place a significant draw on the current market supply. The phasing-in period would also recognize the possible need to re-tool to permit increased use of recycled materials.

When plastics or rubber-based products are taken out of service, MTO contractors should collect and return these materials to recycling companies.

For non-structural highway products where the material composition is not plastics or rubber, is the

substitution of a plastics or rubber-based product feasible? The Ministry needs to apply its system of comprehensive field testing procedures to any such proposed change.

4. MTO should consider a trial substitution of plastic lumber in place of treated or conventional lumber in picnic tables and benches. This would permit a rapid preliminary evaluation of the whole concept of plastic lumber on a small-scale, low technical demand area. The MTO might consider doing this in conjunction with other ministries, such as Environrent or Natural Resources where the potential usage would be much higher, but where the MTO's technical expertise would be put to good use.

5. The MTO should consider field testing of plastic lumber for certain low-stress non-structural highway applications (e.g., fence and sign posts, small size sign blanks).

6. With reference to general conclusion 3 above, MTO should consider applied R&D to generate material performance and safety information about waste plasticdrubber-based products. This program may be undertaken in a cost-effective manner on a partnership basis with prospective suppliers and university research groups. We have identified the following areas where published or otherwise available information is lacking about plastics, rubber and/or rubber/plastics blends based on waste materials: Flammability, ignition, flame spread and the possible generation of toxic fumes. Performance and safety information are particularly important if plastics/ rubber materials are to be used where vehicular crashes or grass/brush fires may ignite them. Long-term creep performance. Creep is generally a weakness of thermoplastics and rubber-based products. If rubber/plastics blends were to be used for sign posts or sign blanks, where they have to withstand wind loads under varying temperature conditions, creep may be a problem. Mechanical properties under elevated (35 to 40°C) and low temperatures (-35 to -45°C). It is normally expected that elevated temperatures would tend to increase the plasticity and creep of rubber/plastics blends. Very cold temperatures, on the other hand, embrittle these materials. Reliable information about low vs. high temperature behaviour is generally lacking. Leachability of possible contaminants or material residues. Since waste plastics from which highway products might be made are to be diverted from the waste stream, it is conceivable they might contain food and/or chemical residues which might be leached from the finished product. Repeated recyclability of products made from waste/ rubber/plastics blends.

7. MTO should continue to monitor R&D and commercial activities in the recycling of plastics and rubber.

"

MAT-92-11 21 R d % D + B ? / e w t !

Appendix A A. 1 Computer Literature Survey

Two different computer literature searches were performed, each structured to investigate a different area of the literature. The first survey was aimed at the chemical and mechanical properties of recycled polymers and rubber, along with processes for recycling. The databases searched included: [4*1

Chemical Abstracts Online Civil Engineering Database lntemational Construction Database lntemational Plastics Selector Japanese Govemment and Public Research in Progress The Plastics Rubber Fibres File Government Reports Announcements Plastic Material Selection Database Regional Planning and Building Construction Environmental Research in Progress Environmental Literature

CAS Online CEDB ICONDA IPS JGRlP

KKF NTlS PLASPEC RSWB

UFORDAT ULIDAT

A separate search was performed for polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terepthalate, and rubber. In each case, the search looked for references that included both the named material as well as any one of a selection terms covering recycling ( e.g., recycling, reclaim, reuse, waste etc.). In addition, a separate search was performed to review specifically the literature on plastics and/or rubber blends. The searches were not restricted to English language references, although only the English abstracts of foreign papers were recovered and printed.

The second survey was aimed at references to the use of plastics (either recycled or virgin) in road transportation related applications. The databases searched include d: [431

Transportation Information Service TRIS National Technical Information Service NTlS Materials Business File Compendex Plus Fluidex Engineered Materials Abstract EMA Enviroline Pollution Abstract Chemical Abstracts CAS Online PTS Newsletter Database The Trade and Industry Index

The search was structured to look for references to any of the plastics named earlier (or to plastics or rubber in general) in connection with any one of a list of products that included keywords such as barrier, panel, delineator, fence, post, sign, sound, median, table, parking, street, highway.

In the first survey, by far the bulk of the references were found from CAS Online. In general, they could be divided into three categories:

1. those that discuss the logistics and economics Of collecting and sorting recycled materials:

2. those that discuss the mechanical/chemical aspects of a specific recycling process; and

3. those that discuss the properties and possible uses of recycled resins.

Few references cover all three areas iri detail, since the audiences for the different areas are themselves different. In addition, the level of information available for different resins differed greatly, the rough order being PET > PE > PS, PP, PVC with rubber comparable to PET. For the purposes of this study, the last category is the most important. This is, unfortunately, the category in which the least specific information was found. This is perhaps an accurate indication that plastics and rubber recycling is to a large extent still a developing industry. Much is written about what should be done; less about how to do it; little about what has been done.

In the second survey, again one database provided most of the references - in this case TRIS. By the nature of the search, these references were well-targeted for the purposes of this study. Most of the references were qual- itative, however, tending to report on a more anecdotal basis rather than providing specific technical details.

A.2 Personal Interviews The formal literature survey provides information on technology and activities that have been formally reported - it does not cover activities that are truly current. To determine the current state of plastics and rubber recycling, particularly with respect to activities in Ontario, a series of direct interviews were held. Information was sought regarding a range of topics: availability of materials, processing technologies, recycled products either in production or targeted for production, and MTO user needs. Trade groups, companies active in recycling technologies, companies marketing recycled products, MOE and MTO personnel, municipal waste managers, and academic researchers in the field were all contacted. Their input was essential to the preparation of this report, and provides the basis for most of the body of the study. A complete list of contacts made is given below.

A.3 Telephone / Mail Survey Of the different available forms of recycled plastics and rubber, one category - plastic lumber - differed significantly from all others. Firstly, as a generic substitute for wood it could potentially find use in a range of MTO products. Secondly, it is available frcm a relatively large number of different suppliers, albeit with considerable variation in its make-up. For this reason a separate survey was made of the suppliers of plastic lumber. The Re- cycled Products Guide [44] was used as the source of companies to contact. A request for product information, asking for as much technical detail as possible was mailed out: this was supplemented with telephone calls to solicit more information where necessary. Responses varied from detailed technical data, accompanied by quantities of samples, down to no response at all. A list of companies contacted is given below.

R d % D - M 22 MAT-92- 1 1

The following individuals or organizations were contacted either by mail, by telephone or by direct interview to obtain information for this report.

List; of Contacts Ontario Ministry of Transportation 1201 Wilson Avenue Downsview, Ontario M3M 1 J8

Research and Development Branch Manning, David G. Head, Materials Research

Coomarasamy, A. Research Scientist

Wear, Jack Research Engineer Sec. New Products Committee

(41 6)-235-4688 faX (41 6)-235-4872

(41 6)-235-4678 faX (41 6)-235-4872

(41 6)-235-4699 faX (41 6)-235-4872

Maintenance Branch Salvatori, John N. Supervisor, Special Maintenance Service Unit

Harwood, David Maintenance Systems Administration Management Section, Planning Office

Bucik, Joseph A. Head, Maintenance Management Section

(41 6)-235-3666 faX (41 6)-235-4904

(41 6)-235-3819

(41 6)-235-3818

Traffic Management and Engineering DeMichele, Michael Project Manager, Traffic Devices (41 6)-235-5280 faX (41 6)-235-4904

Surveys and Design Pedersen, Soren Design Development Analyst (41 6)-235-3509 faX (41 6)-235-5314

Purchasing Churchill, Paul Director

Ontario Ministry of the Environment 14th Floor., 2 St. Clair Avenue West Toronto, Ontario M4V 1 L5

Waste Management Branch Coschi, Frank J. Project Engineer, Industrial Program Unit Waste Reduction Section

Koso, Sandor Project Engineer, Industrial Program Unit

Warner, Richard M. Supewisor, Market Development and Promotion Unit

(416)-323-5193 faX (41 6)-323-5031

(41 6)-323-5045 faX (41 6)-323-5031

(41 6)-323-5196

Municipal Government Agencies Innis, Bob Metro Toronto Department of Roads 439 University Avenue Toronto, Ontario, M5G 1Y8 Myint, Tom H., P. Eng. Senior Engineer, Section Head, Water Main Design Metropolitan Toronto Works Department 439 University Avenue, Toronto, Ontario, M5G 1Y8 (41 6)-392-8253 faX (41 6)-392-3817

Non-Canadian Govemment Agencies Lupton, Ken Illinois Department of Transportation 2300 S. Dirksen Parkway Springfield, Illinois 62764 (21 7)-782-3467

Academic Dr. Warren Baker Professor, Queen’s University Kingston, Ontario K7L 3N6

Dr. Steve Balke Professor, University of Toronto Toronto, Ontario

(613)-545-2621 faX (61 3)-545-6669

. (41 6)-978-7495

Trade Organizations and Non-Profit Groups Edgecombe, Fred SPUEPIC 1262 Don Mills Road Don Mills, Ontario M3B 2W7 Nustafu, Nabil CDN Plastic Inst. 1262 Don Mills Road Don Mills, Ontario M3B 2 W

Industry Armstrong, Dan ORUPI and Sons

Bent, Bruce Representative Bent Manufacturing Company 1 281 9 S. Almeda Street Compton, CA 90222

Bullick, Bruce Representative Flex-0-Lite (A Lukens Company) P.O. Box 340, 143 Borden Ave. Belmont, Ontario, NOL 1 BO

Cassissis, Roland Private Interest

(41 6)-477-7628

(213)-638-5141 faX (213)338-3113

(519)-644-1410 fax (519)644-1382

(506)-383-4452 faX (506)-383-4253

MAT-92-11 23 R d % D + g z r * w l l

Cote, Charron Customer Service Supervisor US. Highway Products, Inc. P.O. Box 241 8, Westport CT 06880

Dahl, Michael Representative Eaglebrook Plastics Inc. 2600 W. Roosevelt Rd. Chicago, IL 60608

Dolan, James Representative Triple T Industries 2651 John Street, Suite 1 Markham, Ontario, L3R 2W5

Horn, Jim Chairman Resource Plastics Corp. 383 Elgin Street Brantford, Ontario N3T 6H2

Falcone, Joe Ontario Sawdust Supplies Ltd. 63 Olive Street Holland Landing, Ontario, LOG 1 HO

Francis, David Production Manager Resource Plastics Corp. 383 Elgin Street, Brantford, Ontario

Heffernan, Dan General Manager Custom Cryogenic Grinding Corp. 105 Thompson Rd. E. P:O. Box 1150 Waterford, Ontario, NOE 1YO

Heffernan, Mike Custom Cryogenic Grinding Corp. 105 Thompson Rd. E. P.O. Box 11 50 Waterford, Ontario, NOE 1YO

Hmska, Joseph P. Director, Municipal Support OMMRI 40 King St. W. Suite 3005 P.O. Box 31 6 Toronto, Ontario, M5H 3Y2

Jamali, H. Bani President K.N.B. Recycling Canada 15 rue Garland St. Dollard des Ormeaux, Quebec H9G 285

Kalnins, Ed, P.Eng. Vice President, Construction Miller Paving Limited Miller Avenue, Markham, Ontario P.O. Box 4080, Markham Industrial Park P.O., Markham, Ontario, L3R 9R8

(203)-454-4262 faX (203)-221-1043

(31 2)-638-0006 faX (31 2)-638-2567

(416)-477-8104 faX (41 6)-477-2910

(519)-754-1754 faX (519)-754-1742

(41 6)-895-9356

(41 6)-338-0823 faX (51 9)-754-1742

(51 9)-443-8665 faX (51 9)-443-8441

(519)-443-8665 faX (51 9)-443-8441

(41 6)-594-3456 faX (41 6)-594-3463

(514)-624-5126 fax (51 4)-624-5127

(41 6)-475-6660 Katz. Carl Vice President, Technical Services National Rubber 394 Symington Avenue Toronto, Ontario, M6N 2W3

Kenny, Angus Manager Recycle London P.O. Box 9069, 1 105 Wellington Road S. London, Ontario N6E 1VO

Kust, Brian Safety Stake

Leonov, Erwin Plant Manager WCI Wood Conversion Inc. 69 Eastern Ave, Brampton, Ontario L6W 1x9

McCaig, Robert A. Recycle London P.O. Box 9069, 1105 Wellington Road S. London, Ontario N6E 1VO

Mintz, Gerry President Comprep Systems Inc. 2651 John Street, Suite 1 Markham, Ontario, L3R 2W5

Mohoruk, Terrance G. Manager, Vinyl Recycling Goodrich: Geon Vinyl Division 61 00 Oak Tree Boulevard Cleveland, Ohio, 44131

Mottershead, Gary G. Vice President Recovery Technologies Inc. 5925 Airport Road, Suite 61 2 Missisauga, Ontario, L4V 1 W1

Mullinder, John Executive Director PPEC 701 Evans Ave., Suite 400 Etobicoke, Ontario M9C 1A3

O’Neill, John V.P. Operations Custom Cryogenic Grinding Corp. 105 Thompson Rd. E. P.O. Box 1 150 Waterford, Ontario, NOE 1YO

Rhoades, Craig Atlantic Northem 8306 Wilshire Blvd. Suite 7061 Beverly Hills California 9021 1

Richards, Dennis ESSO (41 63-733-5456

(416)-657-1111 faX (41 6)-657-8379

(51 91-686-8484

(519)-753-3888

(416)-450-5515 faX (41 6)-450-5660

(519)-652-9284 f a (51 9)-652-9447

(41 6)-477-7626 faX (41 6)-477-2910

(21 6)-447-6314 faX (21 6)-447-6479

(41 6)-672-9448 faX (41 6)-673-8538

(41 6)-626-3344 faX (41 6)-626-7054

(519)-443-8665 faX (51 9)-443-8441

(21 3)-278-2938

R c z u ; u p V D - m 24 MAT-92-11

Stasyna, W.J. President RoadBadger Equipment Limited Unit 8,95 Joymar Drive Streetsville, Ontario L5M 3S8

Stephens, Andrew President Eaglebrook Plastics Inc. 2600 W. Roosevelt Rd. Chicago, IL 60608

Svirklys, F.M. President and C.E.0 Domal Industries Inc. 1564 Kingston Rd. Scarborough, Ontario, M1 N 1 Sl

Thurston, Bill Representative Roadmarker Company P.O. Box 1887 Reno, Nevada 89505

Yankiver, Stephen York Manufacturing Services

(41 6)-542-9067 faX (41 6)-567-0900

(31 2)-638-0006 faX (31 2)-638-2567

(416)-698-5238 faX (41 6)-698-3527

(702)-786-1762

(41 6)-740-3080

Companies Contacted for Information Regarding Plastic Lumber

American Plastics Recycling Group Ltd. P.O. Box 68 lonia, MI 48846 Customer Service

Durable Products Inc. 2823 N. Faim’ew Ave. Roseville, MN 4891 7 Mr. Mark Spurr

Green Tree Plastics Technology, Inc. P.O. Box 18254 Anaheim, CA 92817-8254 Mr. Bill Baskind

Hammers Plastic Recycling Corp. 382 South Mountain Ave. #305 Upland, CA 91 786 Mr. Ken lles

National Waste Technologies 67 Wall Street Suite 241 1 New York, NY 10005 Mr. Kevin Brown

Obex, Incorporated P.O. Box 1252 Stamford, CT 06901 Ms. Celeste M. Johnson

Plastic Recyclers Inc. 58 Brook St. Bayshore, NY 1 1706 Mr. Russell McAllister

Replas, Inc. ‘41 1 B Southgate Crt. Mickleton, NJ 08056 Mr. Jeff Lucas

Rivenite Corporation 6121 Highway 98 North Lakeland, FL 33809 Mr L.W. Umstadter

American Container P.O. Box 217 Plainwell, MI 49080 Mr. Marty Winch

Plastic Pilings Inc. 8560 Vineyard, Suite 51 0 Rancho Cucamonga, CA 91 730 Mr. Mike Tuley

Recycled Plastics Industries Inc. 1820 Industrial Drive Green Bay, WI 54302 Mr. Lee Anderson

Trimax of Long Island 2076 5th Avenue Ronkonkoma, NY 11 779 Mr. Anthony Noto

Presto Products Company P.O. Box 2399 Appleton, WI 54913 Mr. Gary Bach

Entek Corporation 722 South Kimball Avenue Southlake, TX 76051 . ,. Mr. James Tumerpres)

Superwood Ontario 2430 Lucknow Drive, Unit 1 Mississauga, Ontario L5S 1V3 Mr. T. Cochran

Plastic Lumber Co. Inc., The P.O. Box 80075 Akron, OH 44308-0075 Mr. Alan E. Robbins

MAT-92-1 1 25 R w c . U u e V D + W

References

(a) Metropolitan Toronto Department of Works, Metropolitan Toronto Solid Waste Composition Study, Project E.O. 89458, Toronto, Ontario, May 1991. (b) Metropolitan Toronto Department of Works, Solid Waste Environment Assessment Plan, Project 307 91 -1 -Phase 3, Toronto, Ontario, July 1991. Environment Canada, Environmental Choice - An- nual Report 7990, Ottawa, Canada, 1990. Waste Management Branch, Ontario Ministry of the Environment, Scrap Tire Management in On- tario, Toronto, Ontario, January 1991. Waste Management Branch, Ontario Ministry of the Environment, Commercial/lndustriaI Waste Plastic Feedstock Procurement and Sensitivity Analysis for a Mixed Plastics Recycling Facility, Toronto, Ontario, December 1990. Modem Plastics Encyclopedia, McGraw Hill Inc., 1221 Avenue of the Americas, New York, NY. See for example: Maine, F., Introduction to Plas- tics, Financial Post Conference - Emerging Plastic Technologies, Toronto, Ontario, March 1 , 1989. Proctor and Redfem Ltd., Mixed Rigid Plastic Container Separation and Recycling Facilify Fea- sibillty Study, Report prepared for EPIC, 1990. Warner, R.M., Plastic Resin Consumption and Plastic Waste Generation in Ontario, MOE Report, 1989. Baker, W. and M. Duhaine, The Use of Reactive Blending in Reclaiming Ground Rubber Tires, Manuscript, 1991. Baker, W.E. and M. Saleem, “Coupling of Reactive Polystyrene and Polyethylene in Melts,” Polymer, 28, 2057, (1987). Cheung, P., D. Suwanda and S. Balke, The Re- active Extrusion of Polyethylene / Polypropylene Blends, Proc. NRCWINRI Symposium “Poly- blends-89,” pp. 8-1, 1989. Simmons, A. and W. Baker, “Compatibility Enhancement in Polyethylene/Styrene - Maleic Anhydride Blends via Polar Interactions,” Polymer Communications, 31, 20,1990. Advances in Materials Technology: Monitor 7990, Plastics Recycling UNIDO Issue No. 18, 1990. Environment and Plastics Institute of Canada, Waste Plastics: Collection, Sorting and Pre- processing, CPI Report, 14pp., 1990. Environment and Plastics Institute of Canada, Waste Plastics Reclamation Processes, CPI Re- port, 1 1 pp., 1990. (a) Society for Plastics Industry, Bulletin, January 1989. (b) National Packaging Protocol, Agenda for Ac- tion presentation, August 1991.

Woodhams, R.T., S. Law and J.J. Balatinecz, Properties and Possible Applications of Wood F- bre-Polypropylene Composites, Proceedings of Wood Adhesives 1990, USDA Forest Service, For- eat Products Laboratory and the Forest Products Research Society, 1990. Mack, W.A., Turning Plastic Waste into Engineered Products Through Advanced Tech- nology, Plastic Waste Management Proceedings by the Society of Plastics Engineers, 1990. Law F., Recycling of Flexible PVC Waste, MOE Report, 1991. Cochran, T., Superwood Recycling the “Un- recycable” ORTECH - Technology Today, 33(3) 10-12,1990. Gibbs, M.L., “Post-Consumer Recycled HDPE: Suitable for Blowmolding,” Plastics Engineering 57-59, 1990. (a) Ontario Ministry of Transportation. Highway and Road Inventory. Program MM13079 Report 28 - Provincial Totals. Toronto, Ontario. 1989. @) Ontario Ministry of Transportation, Highway and Road Inventory, Program MM13079, Report 28 - Provincial Totals, Toronto, Ontario, 1990. (c).Ontario Ministry of Transportation, Highway and Road Inventory, Program MMl3079, Report 2B - Provincial Totals, Toronto, Ontario, 1991 . Plastic Recycling Update, Resource Recycling Irc., Portland, Oregon, 4:2. Plastics News, October 7, 1991, pp. 21 -22. Setterhold, V.C., “Recycling Wocd Fibre in Mu- nicipal Solid Wastes: Opportunity for Government - Industry Partnership,” TAPPl Journal, 74(4) 79- 84, 1991. Cummings, C., “The Economics of Recycling,” Civic Public Works, 1991 . For an Introduction to the life cycle analysis, see: A Technical Framework for Life Cycle Assess- ment, Society of Environmental Toxicity and Chemistry, Washington, D.C., January 1991. Edgecombe, F.H., The Technology of Plastics Re- cycling - An Overview, OCMR / University of To- ronto Symposium on “Wood Plastics Com- posites,” 1991 . Bregnar, W., “Plastic Lumber Gains Attention,” Plastics News, July 22, 1991 . Maczko, J., “Recycling - An Atemative to Landfills for Mixed Plastic Waste,” Plastics Engineering, 1990. Durisol Materials Limited, Durisol - a Composition of Only Natural Materials, Mitchell, Ontario, 1991. Triple-T Industries, Tuming Present Environmental Problems into Growth and Profits, Markham, On- tario, 1991. For example: NCHRP 230, Recommended Pro- cedures for the Safety Performance Evaluation of Highway Appurtancences, TRB, Washington D.C., 1981. Viceroy Rubber and Plastics Ltd., 1655 3upont St., Toronto, Ontario M6P 3T.

26 MAT-92-1 1

The Roadmarker/Contico, Reno, Nevada 89505. Private Communication, Mr. Bob Wise, Pro- curement Manager, Illinois Department of Trans- portation, Springfield, Illinois, August 1991. Private Communication, Mr. C. Katz, National Rubber Co., Toronto, Ontario, 1991. Domal Envirotech Inc., Manholes - Catch Basins - Water Valves, Toronto, Ontario, 1991. Private Communications, Mr. Dennis Richards, Esso “Enviroblock,” Esso Chemical. Omni Products, Portland, Oregon, US. Perchanok, M.S. “Investigation of Fabric Prop- erties for Highway Snow Fence,” MTO, R&D Branch report MAT-92-1 5, 1993. STN International, 2540 Olentangy River Road, P.O. Box 02228, Columbus, Ohio 43202, USA. Dialog Database, Palo Alto, California. American Recycling Market Inc., 7he Official Recyded Products Guide, Volume 3, Number 1, Ogdensburg, New York, 1991.

potential applications in highway laol ,

Documents