ENVIRONMENTALTERMINOLOGY

GUIDE

Pressure Sensitive Manufacturers Association

Pressure Sensitive Manufacturers Association

Sysonby LodgeNottingham RoadMelton Mowbray

LeicestershireLE13 ONU

Telephone: 01664 500055

Third Edition 2000

1. Foreword

We believe that all environmental issues should be viewed with consideration to:

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a) The environmentb) Market demandc) Economic factorsd) End use and performance

Owing to recent legislation relating to packaging waste management, both within the United Kingdom and Europe, there is a need for laminate manufacturers, printers and converters and indeed end users, to become more aware of the environmental implications of the products we use and produce. This is particularly true in respect of growing demand for re-use, recyclability, reduction of waste within the process and the ultimate disposal of waste.

2. Introduction

2.1. Recycling

This is the process of reworking a product to make further use of the raw material.

2.2. Recyclable

This implies that the product in question is able to be recycled due to its make-up. In the case of a label, it must be compatible with the packaging to which it may be adhered. Facilities to recycle may not be widely available.

2.3. Re-use

Many containers can be re-used rather than recycled. Adhesive systems are available that will allow the label to be removed from the product before re-use or recycling, e.g. peelable or water-washable systems.

Environmental factors are complex and may appear to be conflicting. Myths often arise and become “fact”. One such myth is that the tropical rainforests are being destroyed to produce paper. In fact, the clearance of rainforest is mainly a result of the need for fuel, living space of for agricultural use.

The “Paper industry” is not responsible for deforestation. Through sustainable managed forests for paper pulp production, more trees are planted than are cut down; they are harvested as a crop. Also, paper pulp utilises younger tress and forest thinnings. These younger plantations are particularly efficient at removing carbon dioxide and replenishing oxygen to the atmosphere.

Environmental concerns affect all materials and manufacturing processes. The PSMA recognises “environmental responsibilities” with regard to manufacture, application and disposal of our products.

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Legislation is currently being updated and any reference to regulations must be clarified with the supplier. The lists are not exhaustive.

3. Papers

3.1. Recycled Paper

Classification of recycled papers

Recycled feedstock for paper manufacture derives from a variety of waste sources.

The classifications of recycled paper content related to the waste source is as follows:-

Waste classification Examples

AApproved mill waste damaged, faulty goods rejected at

paper mill

BGood quality (woodfree) printers’ and converters’ trimmings,unprinted waste off-cuts and rejected unprinted items

CGood quality (woodfree) office correspondence, computer print-outs,printed waste high quality printed literature

DLow quality (mechanical) newspapers, magazines, cheap catalogues, directories’ waste

These classifications apply equally to both the label face and release paper lines used for self-adhesive laminate manufacture.

The classification system thus provides a means of ranking recycled papers according to their environmental contribution. It should be noted that the environmental considerations relating to de-inking processes may have implications for energy efficiency and possible emission of undesirable effluent.

These classifications can be used to define the recycled paper by waste source e.g. “40/40C recycled” paper would contain 40% of category D, 40% of category C and 20% virgin fibre.

The quantity and classification of recycled waste in label stock may have an effect on the quality of print and converting characteristics.

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3.2. Recycled face paper

The level of recycled content is in effect determined by the quality and performance required. Paper strength, whiteness and printing properties are progressively reduced by increasing the percentage of lower qualities of waste.

3.3. Recycled release liners

Glassine release liners are produced for their strength combined with translucency properties when used in conjunction with automatic label applicators. To include waste fibres in glassine base manufacture may defeat the main objectives, making the product more opaque. It may also reduce the consistency of caliper and strength, which are critical for label conversion, with an increasing tendency for dusting and hence surface contamination during slitting and processing.

The recycling of siliconised backing paper is under development. 100% adhesive free silicone coated glassine and clay coated Draft papers have been successfully recycled – using the longer, higher strength fibres from these products for packaging, sacking and envelope manufacture.

It is possible to recycle siliconised backing paper.

3.4. Low Chlorine Papers

Classification of chlorine free and low chlorine papers

For many years chlorine bleaching has been an accepted process in paper-making to achieve “high white” papers.

Chlorine bleaching has now been identified as a pollutant, and environmentally responsible self-adhesive laminate manufacturers are currently making concerned efforts to reduce chlorine bleaching short-term, and eventually to supply the label market with chlorine free papers.

Standard face materials employed in the manufacture of self-adhesive laminates are normally chlorine bleached which means that up to four kilograms of organic chlorine compounds will be present in the effluent per tonne of pulp produced. The amount of chlorine left in the paper is very small as the majority is washed out and becomes effluent.

Some manufacturers already offer chlorine free and low chlorine papers in addition to standard chlorine bleached papers. With the absence of one agreed set of guidelines or classifications, printers and their customers would understandably be confused by varying classifications and the term “low chlorine”.

To clarify this situation, the Pressure Sensitive Manufacturers Association and the BPIF Roll Label Printers Section have agreed the following classifications:

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a) TCF Total chlorine free (No chlorine gas or compounds used)ECF Elemental chlorine free (No chlorine gas used)

< 0.5 kg per tonne of pulp

b) Low chlorine < 0.5 kg per tonne of pulp

c) All other papers

Standard papers average 1.0 – 4.0 kg per tonne of pulp

N.B. the amounts indicated are organic chlorine compounds in pulping effluent And not present in the finished paper.

Currently available chlorine free papers may have reduced whiteness compared to low chlorine and standard chlorine bleached product.

3.5. Recycled Chlorine Free Papers

Where a recycled paper manufacturer uses a chlorine-free bleaching process, then the paper should be described as such since no chlorine based effluent is released as a result of manufacture. However, the waste paper feedstock may contain paper that was originally chlorine bleached.

This needs clarifying at the point of manufacture as this terminology has yet to be established.

3.6. Composites

In general composite face or liner materials are not suitable for recycling e.g. laminate foils and PE coated liners. These materials are more suitable for incineration and energy recovery, refer to section 7.2.

4.0 Filmic Materials

All plastic filmic materials face and release liners are polymers, i.e. they are made up of repeating chains of the same molecular structure.

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1 Polyester

PET is characterised by its excellent clarity and high temperature resistance. Polyester’s high melting point makes it unsuitable for recycling with other plastics.

2, 4 and 5 Polyolefins

Polythene – PE Polypropylene – PP

PE and PP are “polyolefin” polymers

Polyolefins are the most commonly used packaging materials, and this has resulted in the dramatic growth in the use of PE and PP labels – to allow for recovery and recycling of the package. When Polyolefins are incinerated, no toxic fumes are created.

3 Polyvinyl chloride

The presence of chlorine in the PVC polymer makes waste disposal by uncontrolled incineration unacceptable, due to the creation of potentially hazardous chlorine compounds.

Plastics’ packaging is dominated by Polythene and Polypropylene; PVC is not compatible for recycling with these materials.

6 Polystyrene

PS labels are mainly used for compatibility with PS packaging.

7 Copolymer/mixed polymer blends

There are a growing number of copolymer products, e.g. PE/PS and PE/PP, which have been developed to give specific printing/converting/handling and application features not previously associated with particular single polymer products.

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4.1 Environmental Characteristics

SourcePE Oil

PP Oil

PVC43% Oil

PSOil

PETOil

Disposal

Landfill Yes Yes Yes Yes Yes

Biodegradability No No No No No

Incineration Yes Yes Only possible withSpecialist flue cleaner

Yes Yes

Calorific value High High High High High

The above information is believed to be accurate at the time of publishing although actual recycling characteristics depend on the specific grade of plastic, such as low-density PE or high density PE

For individual description and definition see page 5

Symbols etc.

4.2 Recyclability of Label Containers (Suitable X Not suitable)

LABEL FILM LDPE

**HDPE PP PS PVC PET Paper/Board

CONTAINERTYPE

LDPE * X X X XHDPE * X X X XPP * * X X X XPS X X X X X XPVC X X X X X XPET X X X X X XPaper/Board X X X X X X *

4.3 Environmental Characteristics

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LABEL FILM LDPE**

HDPE PP PS PVC PET Paper/Board

Conformance to packaging regulation levels of heavy metals

Chlorine free X Recycled paper *Virgin board/paper* X

Suitable for disposal by incineration

*

* Given certain circumstances LDPE – low density polyethylene** MDPE is becoming more available MDPE – medium density polyethylene

HDPE – high density polyethylene

4.4 Filmic Liners

Filmic liners typically PE and PP are capable of being recycled.

5.0 Adhesives

5.1 Composition

Adhesive can be defined in the following ways:

a) Polymer – this is the “back bone” of the adhesive

b) Tackifier – the part of the adhesive formulation giving its sticking properties where required

c) Carrier agent – carries the polymer and tackifier components, allowing them to flow during coating and application

d) Additives – a number of specific additives may be used. This will be dependant on the particular properties the adhesive requires

5.2 Adhesive types

Currently adhesives can be grouped under three main headings:

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a) Emulsion systems – this adhesive system is the most widely used, usually based on acrylates and tackifier, using water as the carrier agent.

b) Hot melt systems – this is usually a rubber based system. The process involves “melting” rubber or acrylic to form a thermo-plastic compound.

c) Solvent systems – the carrier agent for this system is solvent based. The polymer may be either acrylic or rubber.

5.3 Solvents

Solvent recovery – the objective of solvent recovery is:

To prevent used solvents entering the waste disposal system and to allow reclamation and re-use of the solvent.

Solvent Emission – this is the release into the atmosphere of solvents (vapours/gases/*voc), during manufacture, particularly during the “drying phase” of adhesive coating.

Solvent self-adhesive laminate manufacturers practise solvent recovery or incineration to control emission. Solvent emission is regulated by legislation.

*voc – Volatile Organic Compound

5.4 Toxicity – Heavy Metals

In general, adhesive systems once in the laminate state are inert and are safe products in accordance with the material description given by the EC Directive 92/59 Article 2 (b). Under normal conditions of use adhesives represent no hazard to health. However, where a specific application, e.g. direct or indirect food contact or compliance with regulations such as EN71 Part III, or BS5665 Part III (TOY) regulations, is required this should be clarified with the supplier concerned.

5.5 Repulpable Pressure Sensitive Adhesives

Conventional pressure sensitive adhesives are a major source contamination in waste paper recycling and have proven to be problematic to the repulping and paper-making process due to the formation of ‘stickies’. This gives an unsightly appearance to paper produced using a significant level of recycled stock of this origin and also causes on-machine problems during its manufacture. However, the industry accepts a level of conventional self-adhesive labelling or recycling into board grades where contamination is less critical.

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The industry has been challenged to engineer repulpable adhesives that enable the following:-

Normal pressure sensitive performance and costs Disperse readily in a conventional repulping operation The particles should not agglomerate to form ‘sticks’ The adhesive should not fully dissolve in the aqueous medium and

contaminate the mill’s waste stream

This challenge is a demanding one and requires specially selected raw materials and formations. Products are now becoming available, albeit the range is limited with respect of pressure sensitive performance. Continued environmental pressures may maintain the impetus to broaden the range of products available and the level of performance achievable, unless the industry adopts a different general approach, such as incineration for energy recovery.

6.0 Inks

The characteristics and type of ink used in the roll label industry will depend on the printing process employed. Processes include:

Flexo Gravure Offset litho Letterpress (flat and rotary) Screen (flat and rotary)

The drying, or curing, and performance of inks is related to the type of ink – more than one ink type can be used in each print process. These include:-

Solvent based Oil based Water based Ultra-violet curing (UV)

Solvent water and oil-based inks by evaporation, penetration and oxidation. UV inks are cured by UV light initiating a chain reaction combining the monomers, i.e. the liquid components into solid polymeric form.

The materials used in the manufacture of inks are mainly organic and thus readily decomposed by incineration. Some substances, for example titanium dioxide used in whites, calcium carbonate in tint mediums and ultramarine and inorganic. Recycling, and in particular the incineration of printed labels, will be influenced by the amount of heavy metals and halogenated compounds that are present in inks. Many of these compounds provide for unique properties in the ink and, reducing their content or eliminating them, will affect behaviour and performance.

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The film thickness of any such ink is much less than the substrate on which it is printed or coated. Decomposition, disposal or recycling of ink products must be considered as a combination of both ink and substrate.

7.0 Waste Disposal

There are various stages throughout the processing and manufacture of self-adhesive labels where waste arises. The most significant post consumer waste is that represented by the label together with the package, which is disposed of in the municipal waste chain.

Currently waste from self-adhesive manufacturing and application (release liners) is mostly landfilled. A shortage of landfill sites and environmental considerations have led to the realisation of the need to re-use and recycle more products.

7.1 Landfill

The long-term effects of water, air and light, under the right set of conditions, can lead to a breakdown of some organic materials. However, the previously held belief that Bio-degradation is a natural methods of returning used materials to the soil is now suspect. Self-adhesive laminate contains very little inorganic material, and in general will contain only background traces of any toxic metals. It is unlikely that these background traces (commonly found in inks and varnishes) will contribute a threat to the environment in landfill. This would also apply to any emissions on leachale that may be produced.

7.2 Incineration/energy recovery

Self adhesive laminates, whether paper, synthetic or composite are high energy materials – i.e. having high calorific value. They represent an ideal source for thermal recycling (incineration) with energy recovery. Contaminated paper waste, such as self adhesive laminate is particularly suitable for incineration, as paper comes from an infinitely renewable source.

Although research is presently concerned with the possibility of removing adhesive from paper or synthetic, and de-inking, the most efficient disposal methods for manufacturers’/converters’ waste in self adhesive laminate form is incineration with energy recovery. The technology of incineration has advanced rapidly, with installations of flue cleaning and scrubbing equipment, which will ensure emissions are strictly controlled.

Mixed plastic waste had posed a problem for incineration – particularly where chlorine compounds are present. Improved incineration techniques have overcome many difficulties.

Licensed disposal sites are available for incineration or landfill.

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7.3 Post-consumer waste recycling

Post-consumer waste may occur in the form of labelled packaging, either at the bottling plant or following end use of the product.

Present research indicated that provided the face material is compatible or “homogeneous” with the container (e.g. paper to paper or polyolefin to polyolefin) then printed self adhesive labels can be recycled with the container. Adhesive, inks and any contents remaining in the container may represent impurities. It is not known what effect impurities have in all areas of the recycling process, but the principle of recycling labelled containers has been established.

Plastics and the recycling of plastic labelled containers are constantly developing. Plastics can be considered amongst the easiest of materials, to recycle, and while the ideal method id to use the same polymer type, it is possible to mix related plastics. The recycled plastics may, however, be of lower quality, but could be used for example, as a central layer in a recycled bottle or in non-critical applications.

The Pressure Sensitive Manufacturers Association is committed to the environment. With the rapidly changing developments in technology, and increasingly stringent legislation, our industry WILL respond to the environmental challenge.

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