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Final report

Polypropylene recovery from post consumer carpets

Report into the recovery of polypropylene from post consumer carpets

Project Name: Envirolink WPC0102 PP recovery from post consumer carpets 2

Date: December 2009

Executive summary

In the UK, up to 500,000 tonnes per annum of post consumer carpets are sent to landfill. Currently, there are very few

recycling processes in existence to handle this waste stream. One option is to size reduce synthetic post consumer

carpets for use in equestrian surface applications. However, this is a relatively low value application and it should be

possible to gain a higher value material from recovered post consumer carpets.

Axion Consulting were commissioned by Envirolink Northwest to investigate a recycling option for post consumer

carpets, in response to an application for technical support made by Carpet Recycling UK.

The aim of the project was to research and develop a recycling process for post consumer carpets made from

polypropylene (PP). Working closely with Carpet Recycling UK, the project was to assess whether a recycled PP product

could be produced from post consumer carpets.

The project consisted of a combination of demonstration trials and laboratory work, all of which took place at Axion

Polymers in Salford. The project involved the following stages:

Size reduction of the carpets using a granulator fitted with a 15mm screen;

Screening of the carpets with a 12mm flip-flop screen;

Laboratory scale extrusion of the clean granulated material; and

Physical properties testing of the extruded polymer.

There were three samples of carpet tested:

PP post industrial carpet; and

PP post consumer carpet mix sourced from a household waste recycling centre (HWRC) in Salford and from a

carpet recycler in Leicestershire.

PP post consumer tufted carpet sourced from a household waste recycling centre (HWRC) in Salford.

An initial sample of post consumer carpet was tested with a portable near infrared (NIR) machine to identify which

carpets were made from PP. Only the PP carpets were granulated and screened. Subsequent preparations for the

laboratory extrusion work indicated that the granulated material was not entirely PP and contained contamination.

Assessment of the sample showed fibres from the carpets, which were identified as nylon and polyethylene

terephthalate (PET). An attempt was made to extrude the material but it was not possible to maintain the extrusion

strand. This issue highlighted the problem of carpets containing a range of fibres made from different polymers.

A second sample of post consumer carpets was sourced from the same HWRC as the first sample, but this time only

carpets of a tufted construction were included. All the carpets were thoroughly tested with a Fourier Transform InfraRed

(FTIR) machine. Only carpet pieces, where both the pile and backing fibres had been confidently identified as PP were

processed.

The granulation trial, in terms of size reduction, was a success. The carpets required manual size reduction to

approximately 20x20cm pieces before granulation, to ensure the carpets did not tangle around the granulator shaft and

block the machine. Additionally the machine was fed slowly to allow plenty of time for the material to be processed and

to prevent blockages from occurring. The granulator size reduced the material and successfully released the pile fibres

from the backing fibres.

The granulated material was then processed over the flip-flop screen. The results of the trial showed that 38% of the

material was oversized and 59% was undersized with a 3% loss. The oversize fraction was the desired product and

assessment of the material showed it was significantly cleaner than the feed material. The undersize fraction contained

a high proportion of small fibres and dust/dirt contamination. The yield loss in the screening trial was high and this was

due to the combination of the granulator and flip-flop screen sizes. For a 12mm flip-flop screen the carpet should ideally

only be granulated to approximately 20-25mm. If a smaller granulated fraction is produced, as in this trial, the flip-flop

screen should then be smaller, at 6-8mm, in order to reduce yield losses.


Date: December 2009

Samples of both post industrial PP carpet and the clean granulated post consumer carpet were extruded, moulded into

plaques and bars and physical properties tested. The post industrial sample was used as the benchmark against which

the post consumer fraction was compared. The physical tests showed that both the fractions were good but there were

measurable differences between the two samples.

Physical properties test Units Post industrial sample Post consumer sample

Melt Flow Rate (at 230°C,

2.16kg) 6 52

Tensile Mpa 22 23

Elongation @ Yield % 7.3 10.1

Elongation @ Break % 35.1 28.8

Density g/cm3 1.15 1.023

Ash % 17 10

The differences between the two samples are not unexpected as the post industrial material was manufactured recently,

where as some of the post consumer samples may be 10 to 15 years old and made with different techniques and grades

of PP. Not only is the age of the material likely to cause variations, different carpet manufacturers are likely to use

different grades of PP causing more variations. Therefore it is anticipated that the physical properties of the extruded

fibres from post consumer carpets is likely to change between batches of carpets.

A direct comparison with virgin PP is difficult due to the presence of fillers in the carpets samples. However, in general

terms the physical properties of the post industrial sample are good compared to what would be expected from a filled

PP product.

It is thought that the post industrial extruded polymer could be used in injection moulding applications, although further

research with moulding companies would be required to verify the suitability of the material. The post consumer

polymer could potentially be used in medium to lower grade injection moulding applications, such as plant pots or

buckets.

The main conclusions from the project are:

Post industrial carpet can be processed into a product with good physical properties which has potential for use in

a range of applications;

Post consumer carpet, consisting of entirely PP fibres, can be recycled into a product with physical properties

making it suitable for use in medium grade applications;

However, the extruded product from the post consumer carpet is only acceptable if the carpets can be correctly

identified and sorted. Correct identification and segregation of post consumer carpets into an entirely PP

fraction is critical to the viability of a commercial process to recycle carpets; and

Carpets which contain a mix of polymers, including PP, produced a fraction which was not suitable for extrusion

and hence the end market for mixed synthetic carpets is still likely to be equestrian surfaces.


Date: December 2009

Table of contents

1 Introduction ................................................................................................................................ 6 1.1 Types of carpets................................................................................................................. 6 1.2 Existing recycling techniques ............................................................................................... 8 1.3 Existing end markets for post consumer carpets .................................................................... 9

2 Demonstration trials ................................................................................................................. 10 2.1 Sourcing of the carpets for the trials ................................................................................... 10 2.2 Initial demonstration work.................................................................................................. 13 2.3 Size reduction ................................................................................................................... 15

2.3.1 Granulation .......................................................................................................... 15 2.3.2 Results of granulation trial ..................................................................................... 16 2.3.3 Discussion of results .............................................................................................. 16 2.3.4 Shredding ............................................................................................................. 17 2.3.5 Results of shredding trial ....................................................................................... 17 2.3.6 Discussion of results .............................................................................................. 17 2.3.7 Alternative size reduction options ........................................................................... 18

2.4 Screening and cleaning ...................................................................................................... 19 2.4.1 Flip-flop screen ..................................................................................................... 19 2.4.2 Results of flip-flop trial........................................................................................... 20 2.4.3 Discussion of results .............................................................................................. 22 2.4.4 Alternative cleaning options ................................................................................... 22

2.5 Extrusion .......................................................................................................................... 23 2.5.1 Laboratory extrusion ............................................................................................. 23 2.5.2 Physical properties comparison of extruded products ................................................ 23

2.6 Discussion of demonstration trial results .............................................................................. 25 3 Waste carpets volumes in Northwest England ........................................................................ 26

3.1 Carpet specification ........................................................................................................... 26 3.2 Composition of mixed carpet waste ..................................................................................... 26 3.3 Source of waste carpets ..................................................................................................... 26

3.3.1 Industrial sources .................................................................................................. 26 3.3.2 Commercial waste sources ..................................................................................... 26 3.3.3 Domestic waste sources ........................................................................................ 27 3.3.4 Total carpet waste ................................................................................................ 27

4 Proposed recycling flowsheet for waste PP carpets ................................................................ 28 4.1 Mass balance for recycling PP carpets ................................................................................. 29

5 Commercial viability of recycling post consumer carpets ....................................................... 32 6 Conclusions ............................................................................................................................... 37 Appendices ............................................................................................................................................ 38 Appendix 1 - Carpet Recycling UK ‘Tufted PP carpet waste arising in NW’, 2009 .............................. 38

List of figures Figure 1 Schematic of woven carpets ..................................................................................................................... 6 Figure 2 Schematic of tufted carpets ...................................................................................................................... 7 Figure 3 Flow diagram of demonstration trials ....................................................................................................... 10 Figure 4 Samples of carpets which were granulated .............................................................................................. 11 Figure 5 Sample of carpet showing backing and pile fibres ..................................................................................... 11 Figure 6 Second backing layer peeled back to show primary backing layer and latex ................................................ 12 Figure 7 Sample of contaminated carpets ............................................................................................................. 13 Figure 8 Granulator set up .................................................................................................................................. 15 Figure 9 Granulated carpet .................................................................................................................................. 16 Figure 10 Shredded post consumer carpets .......................................................................................................... 17


Date: December 2009

Figure 11 Flip-flop screen at Axion Polymers ......................................................................................................... 19 Figure 12 Flip-flop screen processing the granulated carpets .................................................................................. 20 Figure 13 Oversize output from flip-flop ............................................................................................................... 21 Figure 14 Undersize output from flip-flop ............................................................................................................. 21 Figure 15 PP test bars moulded from post industrial carpets .................................................................................. 24 Figure 16 PP test bars moulded from post consumer carpets .................................................................................. 25 Figure 17 recycling process for waste PP carpets .................................................................................................. 28 Figure 18 Option 1 mass balance for the recycling of PP carpets ............................................................................ 29 Figure 19 Option 2 mass balance for the recycling of PP carpets ............................................................................ 30

List of tables Table 1 Granulator mass balance ......................................................................................................................... 16 Table 2 Mass balance for flip-flop trial .................................................................................................................. 20 Table 3 Physical properties results from the carpet samples .................................................................................... 23 Table 4 HWRC case studies ................................................................................................................................. 27 Table 5 Economic payback calculation for option 1................................................................................................. 33 Table 6 Economic payback calculation for option 2................................................................................................. 35

Glossary FTIR Fourier Transform Infra Red Spectroscopy

NIR Near Infra Red Spectroscopy

PET Polyethylene Terephthalate

PP Polypropylene

Acknowledgements

Axion Consulting would like to thank Carpet Recycling UK for their input and assistance with the project.


Date: December 2009

1 Introduction Carpets have been in use for many years and the quantities entering the UK waste stream are in excess of half a million

tonnes per year. Currently in the UK the recycling rate for carpets is less than 2%, with only a few companies involved

and recycling processing only in development stages.

Carpets are considered to have high carbon footprints as they contain virgin plastic manufactured from petrochemicals.

The manufacturing process to produce the virgin raw materials for carpets can be energy and carbon intensive.

The aim of this project was to research and develop a recycling process for carpets made from polypropylene (PP).

Working closely with Carpet Recycling UK the project was to assess whether a PP product could be produced from the

carpets.

The two types of carpet considered by this project were:

Post industrial carpet which has never left the manufacturing site and is therefore clean; and

Post consumer carpets, including off-cuts from installation and uplifted flooring which is dirty.

Recycling of the post consumer carpets was the main focus of work for the project.

1.1 Types of carpets There are various types of carpets in the domestic market. The two most common are:

Woven; and

Tufted.

Figure 1 and Figure 2 show diagrams of tufted and woven carpets to illustrate the differences between the two styles.

Figure 1 Schematic of woven carpets1

Woven carpets are manufactured by weaving the carpet pile onto other fibres with a loom. Woven carpets tend to

contain a range of coloured yarns to produce intricate patterns. The manufacturing process also tends to be quite slow.

The fibres onto which the carpet pile is woven can be polyester, whilst the pile itself tends to be PP.

1 http://www.armelcarpet.com/images/WovenDiag.gif


Date: December 2009

Figure 2 Schematic of tufted carpets2

Tufted carpets are the most common type for use in domestic applications. They are manufactured by attaching the pile

fibres to a backing layer. The pile fibres can be natural materials such as wool or synthetic materials such as PP. A latex

compound is then used to bond the fibres to the backing layer. A second backing layer is added to the carpet,

sometimes this can be made of hessian but it can also be manmade fibres such as PP. The second backing layer

provides stability to the carpet.

Various types of materials can be found in carpets including:

Plastics and rubber:

o PP;

o Polyester/PET;

o Nylon;

Natural fibres:

o Wool;

o Hessian/Jute;

There are a wide variety of carpet manufacturers and the age of post consumer carpet found in the waste stream can

vary from a few years to over 15 years. End of life carpets can contain significant quantities of dust/dirt, which need to

be removed during the recycling process.

2 http://www.fine-flooring.com/TuftedDiagA.gif


Date: December 2009

1.2 Existing recycling techniques Research undertaken by Axion into carpet recycling indicates that recycling processes do exist abroad and significant

work has already been conducted into suitable processes. In particular, both the United States and Europe have been

carrying out research into carpet recycling for a number of years.

Founded in 2002, the Carpet America Recovery Effort (CARE) is a joint industry-government non-profit organisation.

Their mission is to develop market based solutions for recovering value from post consumer carpet. However in America

over 80% of the carpets handled by CARE were made from nylon and only 8% were PP.3 Carpets in America also tend

to have deeper piles than UK carpets and the recycling technologies developed in the USA typically involve shearing of

the pile from the carpet backing, rather than shredding or granulation. For example, InterfaceFLOR in Georgia, America,

has a recycling process which shears off the pile fibres from the carpets. The main focus for the process is the recovery

of nylon 6 and 66 for use in new carpet tiles, but a PP fraction is created by the process which is then sold on4.

In Europe, in the late 1990’s, extensive work was done by the European carpet industry to develop a recycling route for

post consumer carpets. The project involved the following stages5:

The RECAM (Recovery of Carpet Materials) Project. The aim of RECAM, which was funded by the European

Community, was to develop an economically feasible, closed loop system for post consumer and post industrial

carpet waste. The project studied the collection, identification and sorting of carpets as well as the recovery of

high grade materials and energy from residual fractions. The project was completed in 1999;

Development of the technology. This involved finding or developing the necessary technical equipment and tools

for the recycling process. One element of this was COCARE, a coding system to allow for easy identification of

carpets; and

Pilot plant. Carpet Recycling Europe (CRE) was established in 1998 with the aim to implement the findings from

the RECAM project. The project involved the building of the first automated sorting plant for carpets in Mainz,

Germany. It was the intention of the project to use the pilot plant to gather data to allow for an economic,

technical and environmental assessment of the carpet recycling process. The plant was able to process

approximately 3.5 tonnes per hour. Although the plant demonstrated technical feasibility, the economic

conditions were unfavourable, due to landfill being the cheaper option at the time. Because of this the plant

closed in August 2002. The project concluded that although technically feasible, carpet recycling would require

more favourable economic conditions for the process to become viable.

The work completed by RECAM and CRE provided useful know how into the recycling of carpets.

In Germany in 1999 Polyamid 20006, the largest nylon 6 carpet recycling facility, was built. The plant reclaimed post

consumer carpet from all over Europe and utilised chemical depolymerisation and re-polymerisation of nylon 6 and

extrusion compounding of nylon 66. The plant also recovered PP which was sold for use in fibre reinforced concrete

panels. Again due to difficult economic conditions and a lack of suitable feed material the plant shut in June 20037,8.

Currently in the UK, there is no well developed recycling sector for post consumer carpets. The UK's first carpet recycler

was Swindon based Greenback Recycling which was set up only a few years ago. However Greenback does not produce

an extruded product from the carpets they receive.

3 CARE 2008 Annual Report - accessible as www.carpetrecovery.org 4 http://www.interfaceflor.com/Default.aspx?Section=3&Sub=6&Ter=24 5 http://www.gut-ev.de/en/frames_issues_rec.htm 6 http://www.ptonline.com/articles/200205cu2.htm 7 http://www.concentro.de/downloads/fallstudie_3_en.pdf 8 http://etd.gatech.edu/theses/available/etd-08222008-132753/unrestricted/subbiah_valli_200812_mast.pdf

http://www.carpetrecovery.org/

http://www.interfaceflor.com/Default.aspx?Section=3&Sub=6&Ter=24

http://www.gut-ev.de/en/frames_issues_rec.htm

http://www.ptonline.com/articles/200205cu2.htm

http://www.concentro.de/downloads/fallstudie_3_en.pdf

http://etd.gatech.edu/theses/available/etd-08222008-132753/unrestricted/subbiah_valli_200812_mast.pdf


Date: December 2009

1.3 Existing end markets for post consumer carpets There are various end markets which currently exist for material from post consumer carpets. The main, relatively low

value, end market in the UK is the equestrian or the horticultural market. In the equestrian market the material

recovered from the carpets is used as an additive to sand based all-weather surfaces. surface material and laid on the

ground. Once the carpet has been used as an equestrian surface the plastics cannot be recovered further.

Although not a well developed option in the UK, the materials recovered from carpets have the potential for use in a

range of every day products including:

Plastic park benches;

Road cones;

Compost bins;

Plastic car parts;

Soil erosion protection;

Underlay;

Insulation;

Building products; and

Sports surfaces.

The use of materials recovered from carpets in the manufacture of new carpets, closed loop recycling, is currently

uncommon.


Date: December 2009

2 Demonstration trials The overall project plan was to demonstrate a possible recycling process for post consumer PP carpets.

The flow diagram in Figure 3 shows the various demonstration trials completed as part of the project. The three main

stages were:

Size reduction by granulation;

Screening of the granulated material with a flip-flop screen to remove fines; and

Laboratory scale extrusion trials and physical properties testing.

Figure 3 Flow diagram of demonstration trials

Post-consumer PP carpets

Granulation of carpets at

Axion Polymers

Screening of granulated

carpets with flip-flop

screen at Axion Polymers

Sample of granulated

carpet

Sample of screened

granulated carpet

Carpet Recycling Trials

Extrusion and physical properties testing of samples

2.1 Sourcing of the carpets for the trials The project involved collecting post consumer carpets from the Cobden Street HWRC in Salford and a carpet recycler in

Theddingworth, Leicestershire.

The initial trial used carpets which were tested with a handheld Near Infrared (NIR) Spectrometer to identify the

polymers the carpets were made from. The sample comprised of both woven and tufted carpets. Most of the carpet

pieces were large and had clearly been uplifted and rolled up. There were a few small off-cut pieces which were clean

and appeared to have not been used.

A second quantity of carpets was also sourced from the same facility and was tested with a Fourier Transform Infrared

(FTIR) machine to identify the polymers present. The second sample consisted of only tufted style carpets. The

photographs in the figures below show the various pieces of carpet.


Date: December 2009

Figure 4 Samples of carpets which were granulated

Figure 5 Sample of carpet showing backing and pile fibres


Date: December 2009

Figure 6 Second backing layer peeled back to show primary backing layer and latex

Figure 5 and Figure 6 show tufted carpets but with subtle differences. Tufted carpets have tufts individually inserted

into a lattice backing layer by a needling technique. A latex compound is then coated onto the backing to anchor the

tufts in place. An additional backing layer is then added to provide stability and strength. In Figure 5 the additional

backing layer is also a ‘scrim’ or lattice i.e. the same as the lattice layer onto which the tufts were initially attached,

which gives the backing a mesh like appearance. In Figure 6 the additional backing layer is an artificial ‘felt’ like fabric

made from PP. Peeling the ‘felt’ layer back shows the latex compound and lattice backing layer onto which the tufts

were inserted. The tufts, lattice layer and ‘felt’ in both of the above samples are all made from PP.


Date: December 2009

2.2 Initial demonstration work Prior to any trials being conducted on post consumer carpet a small amount of initial test work was conducted with post

industrial carpet.

The post industrial carpet sample would form the benchmark against which the post consumer carpet could be

compared. It was anticipated that the results from the post industrial carpet would be as good as could be obtained for

recycled carpet, as the carpet has never been laid and therefore was not contaminated with dirt or dust.

Testing of the post industrial carpet comprised of:

Melting small pieces of the carpet - this was necessary in order to be able to granulate the material using the

laboratory scale granulator;

Granulation of the carpet with a 3mm screen;

Extrusion of the granulated carpet; and

Moulding of test plaques and bars to conduct physical properties testing on the extruded polymer.

The results from the initial post industrial carpet trial were very promising and hence the project proceeded according to

the plan in Figure 3. Prior to granulation the carpets were assessed with a hand held NIR scanner and only the carpets

with a PP signal were processed. During the preparations for the extrusion stage of the trial it was discovered that the

carpets were not entirely PP and the granulated material contained contamination in the form of PET and nylon, see

Figure 7.

Figure 7 Sample of contaminated carpets

In Figure 7 there are visible fibres which have not melted, which were identified as PET and nylon. Both PET and nylon

have higher melting points than PP and hence did not melt in the extrusion preparation stage.


Date: December 2009

The contamination meant that the extrusion process would need to operate in excess of 300°C to ensure all the fibres

melted and extruded correctly. In turn this would have a significant detrimental effect on the physical properties of the

PP component. Based on this a second sample of post consumer carpets was sourced which were visually identified as

of a tufted construction. These pieces were thoroughly tested with an FTIR machine to ensure all fibres within the

carpets were PP.

The following sections report on the processing of the second sample of post consumer PP carpets.


Date: December 2009

2.3 Size reduction The first stage of the recycling of post consumer carpets is a size reduction process. The two main size reduction

techniques are:

Granulation; and

Shredding.

2.3.1 Granulation

A small scale, hand fed granulator with a 15mm screen at Axion Polymers was used for the granulation trial. Figure 8

shows a photograph of the granulator used for the trial.

The aim of the trial was to test the ability of the granulator at size reducing the carpets and to assess the output product

from the granulation process.

The carpets had to be manually size reduced prior to being fed into the granulator to pieces approximately 20-30mm in

size. This was to prevent the carpet pieces from becoming entangled in the granulator shaft and blocking the machine.

Figure 8 Granulator set up

The pieces of carpets were fed by hand into the top of the granulator. The granulated material comes out at the bottom

of the granulator and is sucked through to the collection bag. The material passes through a cyclone, prior to the

collection bag, which removes some of the dust from the granulated material.


Date: December 2009

2.3.2 Results of granulation trial

Due to the manual way in which the granulator was fed it was not possible to measure the throughput. The material

was purposefully fed slowly to ensure the system would not block and hence the time taken to process the material

would not reflect the actual throughput rate which could be achieved in a commercial scale process.

Table 1 Granulator mass balance

kg % kg %

Feed 11.97 100% Granulated material 11.70 98%

kg %

Losses 0.27 2%

Granulation

Figure 9 Granulated carpet

2.3.3 Discussion of results

The granulator trial was successful. The granulator did not block and appeared to be able to process the carpets with

relative ease. However it was necessary to manually size reduce the carpets prior to granulation to prevent tangling

around the granulator shaft. In a commercial process a pre size reduction stage is likely to be required. It is probable

that the pre size reduction stage would require some manual input, albeit the size reduction itself could be done with a

cutting machine.


Date: December 2009

The granulator successfully size reduced the material. A good degree of separation was achieved with a significant

quantity of the pile fibres being released from the backing fibres. The granulation action was also sufficient to remove

some of the latex from the pile fibres.

2.3.4 Shredding

As a comparison to the granulation trial a shredding trial was conducted by Carpet Recycling UK at MachTech Service in

Rochdale, UK.

2.3.5 Results of shredding trial

Figure 10 Shredded post consumer carpets

The carpet material used in the shredder trial was different to that used in the second granulator trial, hence the

different coloured fibres seen in the photographs. The shredded carpets were taken from the initial sample of carpets

which were not exclusively PP. The carpets had been identified as having both PP pile and PP backing but the sample

had not been segregated into woven and tufted carpets. It is thought that the non-PP warp fibres in the woven carpets

were the source of the contamination seen in the partially melted material from the granulation trial.


In contrast to the granulated carpets the shredded material contained more pieces of small complete carpet. The size of

the fibres in the shredded material is smaller than in the granulated material. There are some noticeable pieces of latex

within the shredded sample, where as in the granulated sample there are not many latex pieces visible.


Date: December 2009

The pile in the granulated sample pulls apart to create a cotton wool like material but this is not the case with the

shredded carpet, where the fibres have remained as short twisted piles.

2.3.7 Alternative size reduction options

The main alternative technique for size reducing carpets is the shearing technique used in America. The shearing

technique works by shaving the pile fibres from the backing layers of the carpet. This produces two fractions; one

consisting of the pile fibres and one of the backing layers. Typically the latex backing is disposed of, whilst the carpet

pile fibre is processed through a screen or dry cleaner, then extruded and pelletised.

In the past shearing has been considered an unsuitable technique for the recycling of carpets in the UK, as the pile on

UK carpets is generally too short. Development work on shearing of short-pile carpet has now started but it is likely that

the yield of pile fibres recovered by shearing would be too low for the process to be economically viable.


Date: December 2009

2.4 Screening and cleaning Post consumer carpet can contain significant quantities of dirt and other forms of contamination. In order to have a

clean fraction for the extrusion stage the granulated material was processed over a flip-flop screen to remove the fines

and dust.

The flip-flop screen was chosen as the technique to clean the granulated carpet because of the action it creates. The

movement of the flip-flop screen back and forth causes the material to jump up and down as it travels down the screen.

This motion results in a high G-force screening action. It was hoped that this would cause the dust, dirt and possibly

latex compound to be liberated from the granulated carpet.

2.4.1 Flip-flop screen

Figure 11 shows the flip-flop screen used for the trial, which has a 12x12mm deck.

Figure 11 Flip-flop screen at Axion Polymers


Date: December 2009

2.4.2 Results of flip-flop trial

Figure 12 Flip-flop screen processing the granulated carpets

Table 2 Mass balance for flip-flop trial

kg %

Losses 0.20 3%

kg % kg %

6.36 100% 2.41 38%

kg %

3.75 59%

ScreeningGranulated

material

Oversize

fraction

Undersize

fraction


Date: December 2009

Figure 13 Oversize output from flip-flop

Figure 14 Undersize output from flip-flop


Date: December 2009


The flip-flop screen was able to process the granulated material. The results of the trial showed that 38% of the

material was oversized and 59% was undersized, with a 3% loss of material. The oversize fraction was the desired

product and a visual assessment of the material showed it was significantly cleaner than the feed material. The

undersize fraction contained a high proportion of small fibres and dust/dirt particles.

The yield loss in the screening trial was high, which was due to the screen sizes used in the two trials (granulation and

flip-flop screen). For a 12mm flip-flop screen the carpet should ideally only be granulated to approximately 20-25mm.

If a smaller granulated fraction is produced, as in this trial, ideally the flip-flop screen should then be smaller, at 6-8mm,

in order to reduce yield losses.

During the trial it was observed that the material tended to get caught as it travelled down the screen and rolled like

tumble weed. On occasions manual intervention with a broom was required to keep the material moving down the

screen.

Although the flip-flop screen was able to remove the dust and dirt, it would be advisable to conduct further work with

other types of screens and screen sizes in order to select the most suitable screen for processing of carpets.

2.4.4 Alternative cleaning options

A Pla.to dry cleaning unit could be used as an alternative method to remove the dust and fines from the size reduced

carpet. The Pla.to dry cleaning unit has a screen with beaters which knocks the material against itself and the screen,

with the dust being removed from the carpet through the screen. The Pla.to dry cleaner does not require water to clean

the material which is an advantage. However the cost of Pla.to dry cleaner is in the region of €200,000, which is

significantly more than a basic flip-flop screen.

As the results from the flip-flop screen trial were promising the decision was made that a trial with a Pla.to dry cleaner

was unnecessary.


Date: December 2009

2.5 Extrusion The following two samples were extruded using a laboratory scale extruder:

Post industrial material; and

Post consumer granulated and flip-flopped carpet.

2.5.1 Laboratory extrusion

In order to be able to process the carpets with the laboratory equipment at Axion Polymers the carpets required partial

melting. The partial melting was achieved by placing small samples of granulated carpet in a vacuum forming machine

for a short period of time. After partial melting the carpets were granulated to 3mm, the particle size required for the

extruder feed system.

Both samples were extruded using the laboratory scale extruder without any complications.

An attempt was also made to extrude the initial sample of carpet which contained PET and nylon contamination.

However, the contamination caused the strand from the extruder to blow and the material spluttered from the nozzle.

The material had been dried prior to extrusion and so its inability to extrude was not due to moisture content.

2.5.2 Physical properties comparison of extruded products

The samples of post industrial and post consumer carpet underwent a number of physical properties tests:

Melt Flow Rate (MFR). The MFR is the number of grams of polymer that can be pushed out of a capillary die of

standard dimensions (diameter 2.095 mm, length 8.0 mm) under the action of standard weight (2.16 kg for PP,

at 230°C) in ten minutes (ASTM Standard 1238). The usual melt index range is from less than 1.0 (called

fractional) to up to 100 for injection moulding. The higher the MFR, the easier the PP fills the plastic mould and

the easier the injection or blow moulding process. As the MFR increases, some of the physical properties, such

as impact strength decrease;

Tensile strength (Ultimate) (MPa). The ultimate tensile strength is the maximum stress a material can withstand

when subjected to tension, compression or shearing. Typical PP tensile strengths range from 20-80 MPa9;

Elongation at point of yield (%). The elongation at point of yield measures the elongation to the point where the

maximum stress is applied;

Elongation at break (%). The elongation at break measures the elongation at the point of rupture;

Density (g/cm3); and

Ash (%). The ash test indicates the content of filler (typically chalk) within the polymer.

Table 3 Physical properties results from the carpet samples

Physical properties test Units Post industrial sample Post consumer sample

MFR (at 230°C, 2.16kg) 6 52

Tensile Mpa 22 23

Elong @ Yield % 7.3 10.1

Elong @ Break % 35.1 28.8

Density g/cm3 1.15 1.023

Ash % 17 10

Table 3 shows the results of the physical properties testing of the two samples. The post industrial sample formed the

base case against which the post consumer material was compared. The physical property tests showed that both the

fractions were good but there were measurable differences between the samples.

9 http://encyclopedia.stateuniversity.com/pages/21823/tensile-strength.html

http://encyclopedia.stateuniversity.com/pages/21823/tensile-strength.html


Date: December 2009

The post industrial sample has a MFR of 6, whilst the post consumer sample MRF was 52. This means the post

consumer sample may be easier to mould, but is likely to have a lower impact strength. The tensile strengths of the two

samples are similar. The post industrial sample has a lower elongation at yield than the post consumer sample, but a

higher elongation at break. The post industrial sample stretched 7.3% before the maximum force was reached, whilst

the post consumer sample stretched 10.1% before maximum stress was achieved. However the post industrial sample

was stretched 35% before breaking, whereas the post consumer sample was only stretched 29%. The post industrial

sample had 17% filler content, while the post consumer material had 10%.

The differences between the samples are not unexpected as the post industrial material has been manufactured

recently, where as some of the post consumer samples may be 10 to 15 years old and made with different

manufacturing techniques and polymers. Different manufacturers are likely to use different grades of PP with different

quantities of fillers. The melt flow index of the PP may change during manufacturing of the carpets due to the sheer

forces created in the manufacturing process. Therefore it is highly probable that different batches of post consumer

carpet will demonstrate different physical properties to those stated above due to variations in the age, type and

manufacturer of the carpets.

A direct comparison of either result with virgin PP is difficult due to the presence of fillers in the carpet samples. In

general terms the post industrial sample had good physical properties compared to what would be expected from a

virgin filled PP.

The colour of the extruded PP is influenced by the colour of the carpets forming the feed material. Figure 15 and

Figure 16 shows the test bars which were made from the post industrial and post consumer carpets. Both extruded

polymers are brown in colour, with the post consumer sample being darker than the post industrial.

It is likely that the PP produced from post consumer carpets would require the addition of master batch to make the final

product black. Black PP will be more attractive to potential customers and hence should be sold for a higher price.

Figure 15 PP test bars moulded from post industrial carpets


Date: December 2009

Figure 16 PP test bars moulded from post consumer carpets

It is thought that the post industrial extruded polymer could be used in injection moulding applications, although further

research with moulding companies would be required to verify the suitability of the material. With the post consumer

polymer it is expected that there would still be a market for the material, likely to be in medium to lower grade injection

moulding applications such as plant pots or buckets.

2.6 Discussion of demonstration trial results Overall the demonstration trials were successful and the project showed that an extruded PP product could be produced

from the post consumer carpets.

The granulator was able to size reduce the carpets without any problems, but care was taken to ensure the feed rate

was slow enough to prevent blockages. The granulator was a suitable size reduction technique for carpets and

produced a slightly different style of output to the shredded material. The shredded particles were smaller and less of

the fibres were released. The granulator output consisted of a cotton wool like material and more of the fibres had been

liberated.

The flip-flop screen produced an oversize fraction which was noticeably cleaner, with significantly less dirt/dust

contamination than the feed material. However, too much of the granulated material was captured in the undersize

fraction. This was due the screen size of the flip-flop screen being slightly too large for the particle size of the

granulated material, hence the loss to the undersize fraction. The trial proved that a screening technique, such as a flip-

flop, could be used to remove the dust and dirt.

The extrusion trial was very successful. The results of the physical properties testing showed that both the post

industrial and post consumer samples of extruded PP were of a good standard and quality; the post industrial sample

had slightly better physical properties than the post consumer sample. Both samples appeared suitable for injection

moulding applications, with the post consumer material likely to be used in medium to low grade injection moulding

applications such as plant pots or buckets.


Date: December 2009

3 Waste carpets volumes in Northwest England The following section is based on information provided by Carpet Recycling UK. The full report by Carpet Recycling UK

can be found in Appendix 1.

The aim of the task was to calculate the volume of post consumer carpet waste available in the Northwest of England.

3.1 Carpet specification Based on the results obtained from the demonstration trials in this project, the waste carpet material must meet the

following specification:

Each piece of carpet to be positively identified as having PP pile fibre;

Carpet type to be of a tufted construction;

All the backing fibres to be positively identified as PP;

The carpet to be dry;

No heavy contamination (for example paint, nails); and

Acceptable for manual handling (for example no pet urine or odours).

3.2 Composition of mixed carpet waste Research indicates that 45% of mixed carpet waste is identified as having a pile fibre made from PP. Of this 45%, 70%

has a synthetic backing. Based on sales the split between tufted and woven carpets is expected to be approximately

85:15 respectively. Typically, woven carpets have backing fibres containing polyester so these carpets can be

discounted. This means that 27% of mixed carpet waste meets the PP fibre and tufted construction criteria.

3.3 Source of waste carpets There are three key sources of carpet waste:

Industrial;

Commercial; and

Domestic.

3.3.1 Industrial sources

In the Northwest of England there is one carpet manufacturing site which produces post industrial carpet waste meeting

the specification. The quantity generated is approximately 20 tonnes per month.

3.3.2 Commercial waste sources

The following results are based on a case study with Flooring UK, a flooring contractor based in Southport and serving

mainly public sector housing contracts. Flooring UK generates approximately ten bales of tufted PP carpets per month,

weighing 3.33 tonnes in total, which gives an annual quantity of approximately 40 tonnes.

Assuming that it would be feasible to collect similar amounts from eleven flooring retailers or contractors in the region,

this would give 450 tonnes per annum.


Date: December 2009

3.3.3 Domestic waste sources

The main route for the disposal of waste carpets from domestic sources is through Household Waste Recycling Centres

(HWRC).

Compositional analysis of the residual waste collected at HWRCs indicates that the carpet content can range from 5%-

15%. A conservative estimate of 8% has been used in the following calculations.

In order for carpet to be collected at HWRCs there must be space on site for a suitable storage container to keep the

carpets dry.

Table 4 shows two case studies for HWRCs in the Northwest of England.

Table 4 HWRC case studies

Area HWRC

sites

Sites which

could collect

carpets

Residual waste to

landfill from suitable

sites

Carpet

waste

(8%)

Assuming a 75%

availability rate for

carpet waste

Merseyside

municipal

waste

16 12 90,000 tonnes 7,200 tonnes 5,400 tonnes

Cheshire 16 6 15,750 tonnes 1,260 tonnes 945 tonnes

Using the information in the above table an estimate of the carpet waste airings in the whole of the Northwest of

England was completed.

It was assumed that 60% of HWRC sites could take a suitable container for carpet collections, meaning 63 of the 103

HWRCs in the Northwest region could be considered.

The residual waste from Merseyside and Cheshire HWRCs accounts for 30% of the total waste in the Northwest region.

Extrapolating the case study results of 6,345 tonnes per annum of carpet waste from Merseyside and Cheshire to the

whole of the Northwest region gives 21,150 tonnes per annum of waste carpets.

However this figure is for all carpet waste and, as stated previously, the composition of mixed carpet waste is such that

only 27% of the material will meet the specification. Hence 5,710 tonnes of post consumer tufted PP carpets could be

collected from HWRCs in the region.

3.3.4 Total carpet waste

The calculations show the following volumes of waste:

Industrial waste - 240 tonnes;

Commercial waste - 450 tonnes; and

Domestic waste – 5,710 tonnes.

Total waste arisings of carpet which meets the specification is estimated at 6,400 tonnes per annum.


Date: December 2009

4 Proposed recycling flowsheet for waste PP carpets Figure 17 shows the proposed process for the recycling of post consumer carpets. One of the main aspects of the recycling process is the correct identification of the carpets to

ensure that only PP carpets are processed through the recycling plant.

The recycling plant requires three main processing stages:

Size reduction;

Screening/cleaning; and

Extrusion.

Figure 17 recycling process for waste PP carpets

Collection of

carpet waste from

a range of sources

Delivery of carpet

waste to central

processing

location

Polymer

identification and

testing of carpets

Segregation of PP

and mixed

polymer carpets

Size reduction of

carpets

Screening of size

reduced carpets

Extrusion of

cleaned carpetsPP pellets

Overall stages required for recycling for PP carpets

Fines fraction

Waste fraction

Non-PP carpets

and PP woven

carpets


Date: December 2009

4.1 Mass balance for recycling PP carpets Two options for the recycling of post consumer PP carpets have been proposed:

Option 1 involves buying in bales of pre-sorted tufted PP carpet at £80/te; and

Option 2 involves buying in size reduced tufted PP carpets at £250/te.

Figure 18 Option 1 mass balance for the recycling of PP carpets

De-baling

stage

Size reduction

stage

Screening

stage

Yield = 80%

Extrusion

stage

Yield = 97%

5000 te/year of

Baled sorted tufted

PP carpet

Cost £80/te

5000 te 4000 te 3880 te of PP pellet

Sell for £500/te

Waste to landfill

1120 te

Disposal cost £60/te

1000 te

5000 te

Power cost

Stage operating 8 hours,

5 days a week

Power cost


5 days a week

Power cost


5 days a week

PP carpet recycling mass balance – Option 1

120 te

Power cost


5 days a week


Date: December 2009

Figure 19 Option 2 mass balance for the recycling of PP carpets

5000 te/year of

Sorted and size

reduced tufted PP

carpet

Cost £250/te

PP carpet recycling mass balance – Option 2

Screening

stage

Yield = 80%

Extrusion

stage

Yield = 97%

4000 te 3880 te of PP pellet

Sell for £500/te

Waste to landfill

1220 te

Disposal cost £60/te

1000 te

Power cost


5 days a week

Power cost


5 days a week

120 te


Date: December 2009

The option 1 mass balance in Figure 18 has the following assumptions:

The process is split into two stages:

o Stage one is the de-baling, size reduction and screening stages. These operate 8 hours a day for 5 days

a week;

o Stage two is the extrusion stage which operates 24 hours a day for 5 days a week;

A feed quantity of 5,000 tonnes per year of post consumer carpets pre-sorted into tufted PP carpets costing

£80/te delivered;

It has been assumed that 100% of the carpets delivered to the plant will meet the specification;

All of the carpets are shredded and screened with a yield of 80%;

The undersize fraction from the screen has no economic value and will be sent to landfill to be disposed of; and

The oversize fraction from the screen is extruded. The extrusion process produces a small quantity of waste

which also has to be landfilled.

The option 2 mass balance in Figure 19 has to following assumptions:

The process is split into two stages:

o Stage one is the screening stages which operates for 8 hours a day for 5 days a week;

o Stage two is the extrusion stage which operates 24 hours a day for 5 days a week;

A feed quantity of 5,000 tonnes per year of sorted and size reduced post consumer tufted PP carpets costing

£250/te;

It has been assumed that 100% of the carpets delivered to plant will meet the specification;

The size reduced carpets are screened, again with a yield of 80%;

The undersize fraction from the screen has no economic value and will be sent to landfill for final disposal; and

The oversize fraction from the screen is extruded. The extrusion process produces a small quantity of waste

which also has to be landfilled.

It should be noted that the landfill disposal cost will increase to at least £68/t in April 2010 when landfill tax

increases to £48/t


Date: December 2009

5 Commercial viability of recycling post consumer carpets The project has shown that from a technical perspective post consumer carpets can be recycled into an extruded PP

material, which has potential use in a range of end markets.

However the commercially viability of the process is dependent on the following factors:

A regular supply of feed material, which meets the specification;

Rigorous identification techniques to ensure that only PP material is processed through to extrusion. If too many

carpets containing non-PP fibres were processed the resultant product would be of too low a grade to be

extruded and hence would not achieve the same market value as the PP pellets; and

Research conducted as part of this project indicated that the key issue for many carpet recycling plants is the

economics of the process. If landfill is a cheaper option than processing, which it has been and in some places

may still be the case, then the economics of the recycling process can be unfavourable.

Based on the information obtained during the project a payback calculation has been completed for each option to

assess the commercial viability of the recycling process.

The payback calculation for option 1 uses the following assumptions:

The plant capacity is 7,500 tonnes per annum;

The project did not select any specific processing equipment and therefore the capital cost estimate is based on

Axion’s own recycling equipment experience. The capital cost takes into account the purchasing of:

o Carpet identification equipment; a hand held NIR sorter(s) or a bench top FTIR machine for quality

control;

o 4te per hour de-baler;

o 4te per hour size reduction machine;

o Screening machine;

o Buffer storage silos before extrusion;

o Three 400kg extrusion machines;

o Conveyors;

o Fire protection;

The calculation assumes that a suitable site and building for the processing facility would be rented rather than

purchased, hence the inclusion of an £80,000 rental cost;

The power cost break down consists of:

o Stage 1 of the process operates for 2,000 hours per annum and 5,000 tonnes of carpet can be de-baled,

shredded and screened. The power cost for stage 1 is £14,000 per annum based on 10p/kW hr;

o Stage 2 requires three 400kg extruders to meet the necessary capacity. This stage runs for 6,000 hours

per annum and processes 4,000 tonnes of carpet which costs £252,000 per annum.

o Total power cost is £266,000;

The labour costs breakdown consists of:

o Labour for stage 1 - de-baling, size reduction and screening:

o Three operatives required for stage 1 working 8 hours a day, 5 days a week at a job cost of £18,000 per

annum per person, gives a labour cost of £54,000;

o Labour for stage 2 - extrusion:

o Extrusion process will operate 24 hours a day, 5 days a week which requires three shifts with three

operatives per shift, with an additional allowance of two personnel, at a job cost of £18,000 per

annum per person, gives a labour cost of £198,000;

o A technical manager at £25,000;

o Total labour cost is £277,000;

Other additional operating costs include compliance costs such as quality control, health and safety and

environmental considerations;

It has been assumed the cost to the processor for the waste carpet to be delivered to the processing site will be

£80/te;

The small quantity of material, from the screening and extrusion process, which requires disposal to landfill costs

£38,100 per annum;


Date: December 2009

The extruded PP pellet has been estimated to sell for £500/te creating just under £2 million revenue per annum;

and

The calculation shows the margin per annum is over £800,000, which gives a payback time of just over one year.

Table 5 Economic payback calculation for option 1

tpa 7,500 te/hr 3.57

Capital cost of plant £ 1,000,000

Operating costsPower Stage 1Basis of operation for debaling, size reduction and screening hr/yr 2,000 De-baler kW hr/hr 20 Size reduction kW hr/hr 60 Screening kW hr/hr 20 Cost (assuming 10p/kW hr) £/hr 10 Power costs £/te of feed 2.80 Overall Equipment Effectiveness (OEE) % 70%Plant input for shredding te/yr 5,000 Stage 1 power costs £/yr 14,000 Power Stage 2Extruder capacity te/hr 1.0 Basis of operation for extrusion hr/yr 6,000 Extrusion (3 x 400kg extruders) kW hr/hr 600 Cost (assuming 10p/kW hr) £/hr 60 Power costs £/te of feed 63 Overall Equipment Effectiveness (OEE) % 70%Material for extrusion te/yr 4,000 Stage 2 power costs £/yr 252,000 Total power costs £/yr 266,000

LabourLabour costs stage 13 operators at 8 hours per day with job cost £18,000 £/yr 54000Labour costs stage 23 shifts with 3 people per shift + 2 spare with job cost £18,000 £/yr 198000Technical management £/yr 25,000Total labour costs £/yr 277,000

OthersRent and rates 10,000 sq ft at £8/sq ft £/yr 80,000

Compliance - quality, safety, environment £/yr 30,000

Insurance £/yr 15,000

Total Operating Costs 668,000

Capacity


Date: December 2009

Table 5 Economic payback calculation Table 5 cont’d

Cost of delivered feed £/te 80 Feed cost £/yr 400,000 Disposal cost (at £60/te) £/yr 38,100

Revenue

PP pellet - value of product £/te 500

Quantity of PP pellet te/yr 3,880

Revenue from PP product £/yr 1,940,000

Total revenue £/yr 1,940,000

Margin £/yr 833,900

Payback time (years) 1.2

The payback calculation for option 2 uses the following assumptions:

The plant capacity is 7,500 tonnes per annum;

The project did not select any specific processing equipment and therefore the capital cost is estimated based on

Axion’s own recycling equipment experience. The capital cost takes into account the purchasing of:

o Carpet identification equipment; a hand held NIR sorter(s) or a bench top FTIR machine for quality

control;

o Screening machine;

o Buffer storage silos before extrusion;

o Three 400kg extrusion machines;

o Conveyors;

o Fire protection;

The calculation assumes that a suitable site and building for the processing facility would be rented rather than

purchased, hence the inclusion of an £64,000 rental cost;

The power cost break down consists of:

o Stage 1 of the process operates for 2,000 hours per annum and 5,000 tonnes of carpet can be screened.

The power cost for stage 1 is £2,800 per annum based on 10p/kW hr;

o Stage 2 requires three 400kg extruders to meet the necessary capacity. This stage runs for 6,000 hours

per annum and processes 4,000 tonnes of carpet which costs £252,000 per annum;

o Total power cost is £254,800;

The labour costs breakdown consists of:

o Labour for stage 1 - de-baling and screening;

o One operative required for stage 1 working 8 hours a day, 5 days a week at a job cost of £18,000 per

annum per person gives a labour cost of £18,000;

o Labour for stage 2 - extrusion:

o Extrusion process operating 24 hours a day, 5 days a week will require thee shifts with three operatives

per shift with an additional allowance of two personnel, at a job cost of £18,000 per annum per

person, gives a labour cost of £198,000;

o A technical manager at £25,000;

o Total labour cost is £241,000;

Other additional operating costs include compliance costs such as quality control, health and safety and

environmental considerations;

It has been assumed the cost for the sorted and shredded carpet to be delivered to the processing site will be

£250/te;

The small quantity of material, from the screening and extrusion process, which requires disposal to landfill costs

£38,100 per annum;

The PP pellet has been estimated to sell for £500/te creating just less than £2 million revenue per annum; and


Date: December 2009

The calculation shows the margin per annum is £47,100 which gives a payback time of 17 years.

Table 6 Economic payback calculation for option 2

tpa 7,500 te/hr 3.57

Capital cost of plant £ 800,000

Operating costsPower Stage 1Basis of operation for screening hr/yr 2,000 Screening kW hr/hr 20 Cost (assuming 10p/kW hr) £/hr 2 Power costs £/te of feed 0.56 Overall Equipment Effectiveness (OEE) % 70%Plant input for screening te/yr 5,000 Stage 1 power costs £/yr 2,800 Power Stage 2Extruder capacity te/hr 1.0 Basis of operation for extrusion hr/yr 6,000 Extrusion (3 x 400kg extruders) kW hr/hr 600 Cost (assuming 10p/kW hr) £/hr 60 Power costs £/te of feed 63 Overall Equipment Effectiveness (OEE) % 70%Material for extrusion te/yr 4,000 Stage 2 power costs £/yr 252,000 Total power costs £/yr 254,800

LabourLabour costs stage 11 operators at 8 hours per day with job cost £18,000 £/yr 18,000 Labour costs stage 23 shifts with 3 people per shift + 2 spare with job cost £18,000 £/yr 198,000 Technical management £/yr 25,000 Total labour costs £/yr 241,000

OthersRent and rates 8,000 sq ft at £8/sq ft £/yr 64,000

Compliance - quality, safety, environment £/yr 30,000

Insurance £/yr 15,000

Total Operating Costs 604,800

Capacity


Date: December 2009

Table 6 Cont’d

Cost of delivered feed £/te 250

Feed cost £/yr 1,250,000

Disposal cost (at £60/te) £/yr 38,100

Revenue

PP pellet - value of product £/te 500

Quantity of PP pellet te/yr 3,880

Revenue from PP product £/yr 1,940,000

Total revenue £/yr 1,940,000

Margin £/yr 47,100

Payback time (years) 17.0

The two payback calculations show that the more economically favourable scenario is to purchase sorted bales of tufted

PP carpet and to size reduce the material as part of the process rather than purchasing already size reduced material.

The main issue with the second option is the high cost of the feed material. Both processes have similar overheads and

revenue but the feed costs are significantly different, hence the difference in the payback times.

If the cost of the feed material in option 1 is increased from £80/te to £150/te the payback time increases to 2.1 years

but overall the economics are still promising. Therefore, there is flexibility in the option 1 model to cope with increased

feed prices.


Date: December 2009

6 Conclusions The main conclusions from the project are:

Post industrial carpet can be processed into a product with good physical properties which has potential for use in

a range of applications including injection moulding;

Post consumer carpet, consisting of entirely PP fibres, can be recycled into a product with good physical

properties making it suitable for use in medium to low grade applications, for example injection moulded plant

pots or buckets. The processing stages required to achieve the product are straight forward and involve size

reduction, screening and extrusion;

Should a carpet recycling plant be of commercial interest further work would be required to select the correct

equipment for each of the processing stages;

However, a critical factor to the success and quality of the extruded polymer is the correct identification of all

polymer fibres within the carpet. Carpets which contain polymers other than PP, for example nylon or PET,

produce a granulated material which cannot be extruded. It is expected that carpets which contain mixed

polymer blends are more likely to be of woven than tufted construction. The probable end market for mixed

polymer carpets remains equestrian surface applications; and

The economics of the recycling process look promising and the assessment considered two possible processing

scenarios of which the option of buying pre-sorted whole carpets was favourable over pre-sorted and size

reduced carpets. The payback period of the first option (buying pre-sorted whole carpets) was just over a

year; whereas the payback for the second option (buying pre-sorted and size reduced carpets) was 17 years.

In conclusion the project has proved that a good quality polymer pellet can be produced from post consumer carpets

made entirely of PP, if all of the carpet fibres are correctly identified.


Date: December 2009

Appendices

Appendix 1 - Carpet Recycling UK ‘Tufted PP

carpet waste arising in NW’, 2009


Date: December 2009


Date: December 2009

Axion Consulting Ltd

Tudor House, Meadway, Bramhall, Cheshire

SK7 2DG

Tel: +44 161 426 7731 Fax: +44 161 426 7732

[email protected] www.axionconsulting.co.uk

mailto:[email protected]

http://www.axionconsulting.co.uk/

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