Design Guide for PET Bottle Recyclabilit Recyclability y
Written by: Cees van Dongen - Coca-Cola Europe Robert Dvorak / Ed Kosior - Nextek Ltd
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UNESDA is the Union of European Beverages Association Its members are soft drinks companies who conduct their business in at least five EU Member States and also national associations from across the EU27 and beyond. Our mission is to support the growth, development and understanding of non-alcoholic beverages at a European level. www.unesda.org
EFBW - The European Federation of Bottled Waters is a non-profit international trade association based in Brussels. Our members are national associations and companies representing the interests of over 500 producers of bottled waters across Europe. EFBW works closely with European and international institutions which regulate on bottled water, including the European Commission and Codex Alimentarius. www.efbw.org
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UNESDA is the Union of European Beverages Association Its members are soft drinks companies who conduct their business in at least five EU Member States and also national associations from across the EU27 and beyond. Our mission is to support the growth, development and understanding of non-alcoholic beverages at a European level. www.unesda.org
EFBW - The European Federation of Bottled Waters is a non-profit international trade association based in Brussels. Our members are national associations and companies representing the interests of over 500 producers of bottled waters across Europe. EFBW works closely with European and international institutions which regulate on bottled water, including the European Commission and Codex Alimentarius. www.efbw.org
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Background The growth in processing post consumer PET bottles for high-end bottle-to-bottle application necessitates that we review and update policies to ensure that our stringent quality standards will continue to be met in the future. The challenge is to maintain availability of high quality material that will, in turn, enable us to use recycled content in bottles without discolouration and other visual defects. The quality of recycled material over time is deteriorating through the increased use of additives, barrier materials, glues, sleeves and other components and materials. Following recent resolutions in the Boards of UNESDA and EFBW to work towards a PET bottle recyclability Code of Conduct for its respective members, an agreed next step is to review their current and new PET bottle specifications against the guidelines for resource efficient PET recyclate to prevent and resolve issues of non-compatibility over the next two years. The aim of these guidelines - a set of specific criteria and recommendations – based on current practice, recycler capabilities and the Design for Recycling Guidelines developed by the European PET Bottle Platform (EPBP), following surveys and questionnaires to members to identify problem areas - is also to reach as many companies as possible, not just UNESDA and EFBW members, and encourage them to achieve compliance with the guidelines by the end of 2012. Also, aiming to broaden the initiative to all parties that play a decisive role in maintaining the highest possible quality of recycled bottles, we call upon other brand owners and holders of private labels to act likewise. Another important aim of the guidelines is to encourage companies that design and market materials and components intended to be used in PET bottles to apply the principle of due diligence. We encourage them to bring their products to the Eu ropean PET Bottle Platform so as to obtain an objective third party assessment of the impact on recyclability of their products.
Guideline details The guidelines, which have been developed over the past year, cover specifications and recommended design options for the body, label and cap of the bottle. All materials must meet the legal requirements for materials and articles intended to come into contact with food. We believe that these guidelines are in reach of every company. They are a reflection of the average recycler capability and try to strike a balance between resource efficiency, the need for innovation and shelf differentiation and recycling practices in Eu rope.
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Executive Summary These guidelines for the design of PET bottles define their ease of recyclability based on choices of colour, barrier layers, closures and label systems and establish criteria that can be used to avoid the production of difficult to recycle bottles to ensure a greater supply of high quality rPET to the market. There are many resources available to packaging designers and PET bottle specifiers that allow them to ensure that any design decisions ensure recyclability of PET bottles back into high quality RPET resins that can be used back into bottles as part of closed loop recycling. This report provides links to key documentation, reports and organisations that have developed and specify protocols that determine the impact of PET bottles and components on the PET recycling stream. A decision making matrix has been developed by Nextek to help categorise the impacts on recyclability of PET bottle packaging. This table, based on the Design for Recycling Guidelines issued by PETCORE and EPBP is not an exhaustive list, but it does provide guidance on items that are „Recycle Friendly‟ or „Problematic for Recycling‟ . PET BOTTLE
RECYCLE FRIENDLY
Colourants, fillers Clear / natural and additives Light (blue or green) tints
Barrier coatings Blended barrier resins & barrier layers Closures Closure liners and seals Labels
Inks Direct Printing Sleeves
Adhesives
Base cups Bottle Size Other components
Clear plasma coatings e.g. CVD SiOx, Monox Other layered barrier materials that separate and do not cause yellowing HDPE / LDPE / PP HDPE / PE+EVA / PP / Foamed Silicone / PET HDPE / MDPE / LDPE / LLDPE / PP / OPP / EPS Wraparound plastic Non toxic Follows EUPIA Guidelines Laser marked production or expiry date PE / PP / OPP / EPS / foamed PET & PET-G (Density < 1g/cm 3). PE Stretch Sleeves Shrink sleeves with perforations and revealing a significant % of the bottle. Water soluble in 60 – 80C Plastic wrap, Minimal glue strip (e.g. lap join). Comply with EuPR guidelines No base cup Diameter > 50mm, Length > 100mm
CONDITIONAL
PROBLEMATIC FOR RECYCLING
Dark blue / black if NIR detectable Dark green and brown Optical brighteners O2 scavengers; UV stabilisers; AA blockers PEN / Amosorb / MXD6 barrier multilayer (if <3% total bottle weight)
Non-detectable Dark, opaque, metallic, solid colourants Any use of fillers. Nanocomposite barrier fillers Bio/Oxo/Photo Degradable Additives
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Materials density > 1 g/cm 3 Metals / PS / PVC Neck Foils Metal / PVC / EVA Silicone (density > 1 g/cm3) Pressure sensitive / self-adhesive labels. PVC / PS / metallised.
Paper / silicone „swimming‟ valves (density <1g/cm3) Wraparound paper labels Metallic foils
Ink direct printed production or expiry date Shrink sleeves with perforations and revealing a significant % of PET bottle; Full body PET shrink sleeves
EVOH >3% in multilayer Amosorb, MXD6 > 5% in multilayer Any direct blended barrier based on ie EVOH, MXD6
Inks that bleed, toxic or hazardous; react with PET Any other direct printing Large areas direct printed PVC / PS / PET-G, other materials with density > 1 g/cm3. Difficult to remove and/or NIR sort with heavy ink coverage.
Strong adhesives with paper labels
Water insoluble (even at elevated temperatures and pH levels)
HDPE / PP / clear PET
Coloured PET and other plastics density > 1 g/cm3 Diameter < 30mm, Length < 100mm. Any polymer components with density > 1 g/cm3; PVC / PLA / PS / PETG RFID tags
Diameter 40 -50mm
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Table of contents 1.0
Introduction and Objectives............................ ................................. ................................. ............................ 6
2.0
Benefits of Adopting these Guidelines................................ ................................. ............................... ........ 7 2.1
Greenhouse Gas (GHG) Savings .................................................................................................................................. 7
2.2
Quality and Consistency of rPET in Closed Loop Applications.................................................................... 7
3.0
Recycling in Context .............................. ................................. ................................. ................................ ....... 7
4.0
Principles of Designing for PET Bottle Recyclability............................... ................................. ................. 8 4.1
Key Steps in a Typical PET Recycling Operation ................................................................................................. 8 Maximum Flake size: 12 mm ..................................................................................................................................... 10
5.0
Bottles – Why Size Matters ........................................................................................................................ 10
6.0
Bottle materials, colourants and additives ............................... ................................ ............................... 11
7.0
6.1
Bottle Materials ................................................................................................................................................................. 11
6.2
PLA Bottles .......................................................................................................................................................................... 12
6.3
PVC & PS Bottles ............................................................................................................................................................. 14
6.4
Clarified PP Materials for Bottles ............................................................................................................................. 14
6.5
PET Colourants & Fillers ............................................................................................................................................... 14
6.6
Direct Printing on PET Bottles ................................................................................................................................... 15
Closures (closure liners & seals) ................................ ................................. ............................... ................ 16 7.1
8.0
Labelling systems & materials .............................. ................................. ................................ .................... 17 8.1
9.0
Closure Liners and Seals .............................................................................................................................................. 16 Paper Labels ....................................................................................................................................................................... 17
Sleeving systems .......................................................................................................................................... 18 9.1
Sorting of Coloured Shrink Sleeves. ....................................................................................................................... 18
10.0
Label adhesives .............................. ............................... ................................. ................................. .............. 20
11.0
Barrier systems (coatings, additives, layers) ............................................ ................................. .............. 21 11.1 Bio-Oxo-Photo-Degradable Additives................................................................................................................... 22
12.0
Other Bottle Packaging Components ............................. ................................ ................................. ......... 23 12.1 Other Components ......................................................................................................................................................... 23 12.2
Base Cups ............................................................................................................................................................................ 23
13.0
PET Bottle Recyclability Decision Matrix............................. ................................. ................................. ... 24
14.0
Contaminants in rPET from poorly designed bottle packaging .......................................................... 25
15.0
Test Protocols for Recyclability ................................. ................................. ............................... ................ 26 15.1 15.2
PET Flake Oven Age test .............................................................................................................................................. 26 Sink Float Separation Test Protocols ..................................................................................................................... 26
15.3
Adhesives – Glue Separation & Removal Test Protocols ............................................................................ 27
15.4
Sorting Tests....................................................................................................................................................................... 27
16.0
Conclusions............................... ................................ ................................. ................................ .................... 30
17.0
Key Links, Reports & Organisations ............................... ................................ ................................. ......... 31 17.1 European PET Bottle Platform ................................................................................................................................... 32
18.0
17.2 17.3
PETCORE............................................................................................................................................................................... 33 APR.......................................................................................................................................................................................... 33
17.4
NAPCOR ............................................................................................................................................................................... 34
17.5
UK – WRAP & BRC On-Pack Labelling Scheme for Packaging ................................................................ 34
References ..................................................................................................................................................... 36
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1.0 Introduction and Objectives The objective of this report is to provide guidelines for PET bottle recyclability and to overview the technical and design related aspects that can negatively impact the recycling of PET bottles. The recycled PET (RPET) market in the European Union (EU) is still developing and issues such as material availability and input material quality have the ability to undermine the market‟s potential growth in closed loop (PET) bottle -to-bottle recycling applications. The potential to recycle bottles back into high-end applications such as bottles can be compromised by many factors including the choice of bottle colour, bottle size, barrier layers, closures composition, and label systems. These guidelines provide a framework for the design of PET bottles and define the ease of recyclability based on choices of colour, barrier layers, closures and label system types and establish criteria that can be used to avoid the development and production of difficult to recycle bottles to ensure a greater supply of high quality rPET to the market.
The purpose is to inform packaging designers of recycling processes and provide a detailed technical description that allows PET bottle designers clearly understand what recyclers want, expect and the do's and don‟ts.
The aim is to provide clear guidance on how to prevent contamination of the clear/light blue bottle stream that potentially can end up in bottle-to-bottle recycling for both new pack designs as well as to allow a redesign of problematic existing bottles and their specifications.
These guidelines also aim to establish a decision making mechanism for the design and approval of PET bottles by defining the recyclability of PET bottle packaging materials and its components but also by providing guidance on the use of materials and components that need to be restricted because of their potential for detrimental contamination of PET recyclate and interfere with current PET recycling processes. The information provided in these guidelines will also allow for improved communication between key department stakeholders such as sales, marketing, technical and packaging designers and allow them to clearly discuss the potential impacts on recycling of current and future developments in PET bottle packaging. The following guidelines are therefore aimed at ensuring that PET bottle packaging released into the EU markets is specified and designed in such a way as to maximise the potential for the packaging to be efficiently recycled with minimal impact on the economics of existing recycling operations and the environment. The guidelines are aimed at providing up-to-date, consistent industry advice to those who specify PET bottles and decide on the details of the packaging being used. It will also help inform brand, marketing and design functions about the impact of their s elections and design on the recyclability of the (new) PET bottle packaging. Given that new materials are constantly being developed and packaging and recycling technologies are also evolving, there is of course a need to periodically review and update these guidelines.
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2.0 Benefits of Adopting these Guidelines By adopting these guidelines across the PET bottle supply chain a number of benefits can be realised. These guidelines can form the basis for inhouse bottle recyclability assessments, help designers make better informed decisions about recyclability and can become a means for PET bottlers, brand owners to approve new PET bottles. Like many sustainable initiatives, this approach is not only best practice for PET recycling but also is inherently good business practice to minimise resource use.
2.1 Greenhouse Gas (GHG) Savings Due to the threat of climate change, the impact of packaging on global warming is being carefully considered by governments, brand owners, industry and community environmental groups. In the UK, Coca-Cola Great Britain (CCGB) and Coca-Cola Enterprises (CCE) have been working together with the Carbon Trust and have measured and calculated the carbon footprints of „Coca -Cola‟, „diet Coke‟ and „Coke Zero‟, covering the emissions generated from cradle to grave. The research illustrated that packaging accounts for between 30-70% of the drink‟s carbon footprint and highlighted the importance of using recycled content and of encouraging recycling post use. The study found that a combination of these two factors can decrease the overall carbon footprint of a product by up to 60%. (BSDA, 2009) Life Cycle Assessment (LCA) of the benefits of recycling packaging by WRAP in the UK has found that for every kilogram of recycled PET that is substituted for virgin PET, 1.5 kilograms of carbon dioxide (CO 2) is saved (WRAP, 2006).
2.2 Quality and Consistency of rPET in Closed Loop Applications PET bottles with ideal design characteristics will help the PET recycling industry improve the quality and consistency of supply of RPET and also improve the efficiency of closed loop PET recycling by minimising yield losses. These improvements will allow greater rates of usage of RPET back into „closed loop‟ PET packaging applications and lead to few er defects in PET bottles due to contaminants. Recyclability should have no detrimental effect on bottle lightweighting initiatives, new designs for bottles shapes or “best in class” developments.
3.0 Recycling in Context The recyclability of PET bottle packaging is not the only aspect that should be considered when assessing the environmental impact of packaging and products. Packaging optimisation, efficient delivery, use of recycled content and reusability are all key aspects to be assessed and incorporated into an overall new PET bottle design strategy.
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Improving the consistency and degree of PET bottle recyclability is however very important as it has significant direct and indirect impacts, including:
PET recyclate quality and end market opportunities,
Consistent supply of high quality PET recyclate back into closed loop packaging,
Economic efficiency of collection, recycling and reprocessing operations.
The PET bottle industry has made significant resource efficiency steps forward through continual lightweighting and these guidelines are designed to complement these initiatives and not to hamper further innovations in lightweighting.
4.0 Principles of Designing for PET Bottle Recyclability There is a number of key overarching principles that are appropriate for all PET bottles. These include:
Design for ease of separation and removal of materials such as closures and labels from PET bottles to allow for ease and efficiency of recycling;
Avoidance of using materials that are known to significantly contaminate and reduce quality of PET;
Use of fewer packaging materials on PET bottles to allow for ease and efficiency of recycling.
4.1 Key Steps in a Typical PET Recycling Operation A: Accept flattened PET bottles in Bales B: De-bale into single bottles C: Remove small objects, glass, dirt, sand, loose caps, etc. via a trommel separator D: Remove loose labels and films and other flexible packaging via ballistic separators or hydrocyclones E: Remove ferrous and non-ferrous metals via magnets and eddy current systems F: Sort into plastic type i.e. 100% PET by NIR/Optical automatic and manual sorters G: Cut bottles into 10 mm flakes in a grinder H: Wash flakes in hot water with detergents and caustic I:
Sink float density separation of PET and closures
J:
Remove loose labels and dusty particles via hydrocyclones
K: Sort out coloured flakes away from clear flakes via optical sorters L: Decontaminate the clear PET flakes by: a.
Decontamination, extrusion and melt-filtration of flakes into granules
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b. Solid-state (in hot gas 200 oC for 4-6 hours) PET granules to decontaminate and increase the intrinsic viscosity (IV) by advancing the degree of polymerisation.
Mechanical recycling processes rely on sorting techniques using near-infrared (NIR) spectroscopy to separate whole bottles, with water based washing and separating processes also being applied. The objective is to clean and separate the different material fractions or plastic types. The processes use differences in the density of the materials for separation in water. Magnetic and inductive metal separators are also employed. Materials which cannot be separated or separate incompletely remain with the recyclate and can impair the quality of the final product. The recycling process is therefore a step by step purification process that starts with commingled and often dirty and mixed bottle feedstock‟s and ends up with washed and cleaned flake that has been sorted to >99.9% PET purity. When the flake has reached sufficiently acceptable purity it is ready to be decontaminated and extruded back into granules in most of the commonly applied processes.
Figure 1. An example of density and softening temperature range for common packaging plastics
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Figure 2. An example of a typical specification for flake purity
Property
Specification
Maximum Flake size: 12 mm
95% < 12 mm
Fines (< 0.5mm or 30 mesh)
< 0.3%
Material source
Food grade Source (1)
Intrinsic viscosity according to ASTM D4603-96
0.76 +/- 0.02
Flake Color
YI
19 max. (2)
a
-
b b
9 max. (2) 4 max. (3)
Bulk Density
300-500 kg/m3
Moisture
< 0.7%
PVC
< 5 ppm
Metal (aluminum, steel)
< 5 ppm
Polyolefins ( HDPE, PP, LDPE,…)
< 50 ppm
PH rise
< 0.5
The following sections of this report are aimed at helping packaging designers, technologists, and other specifiers that design new packaging to ensure that it is highly recyclable and for these guidelines to act as an advisory tool when redesigning or updating existing packaging.
5.0 Bottles – Why Size Matters The diameter and size of a PET bottle are important for the purpose of recovery and also to ensure that they can effectively be ejected during sorting stages. Small PET bottles that are typically used for single serve drinks can be lost in openings in trommels that are designed to remove small contaminant particles. Trommel screen sizes vary between 3050mm and can be square, rectangular or circular in shape. For this reason it is best that bottles have a diameter greater than 50mm and length greater 100mm. This size will prevent the bottles from becoming lost to the recycling process.
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Bottles that have a diameter of 40-50mm are highly likely to fall through openings in trommel screens and at most Plastic Recycling Facilities (PRFs) will end up being sent to landfill. Whilst some recycling plants in countries such as Austria, Belgium, France and Germany are designed to double sort and recover any lost PET products that are removed by the trommel screens, the majority of recycling plants don‟t have facilities to resort or have not been designed to do that. Therefore any small PET bottles that fall through the trommel screens are lost from the recycling stream and end up going directly to landfill. Small bottles are also more difficult to eject due to the smaller surface area that air jets can hit. NIR and optical sorting units use very short bursts of pressurised air to eject and remove PET bottles by polymer type and colour type into designated hoppers. Therefore in summary, PET bottles with small diameters < 40mm could be lost to waste during initial stages of PET recycling when caps and glass are being removed. It is recommended that a minimum diameter of >50mm is used. PET bottles that are shorter than 100mm may not be identified as PET bottles in automatic sorting systems, due to the resolution used on some detectors.
Bottle Size Recycle Friendly
Conditional
Problematic for Recycling
Bottle Diameter > 50mm
Bottle Diameter 40-50mm
Bottle Diameter < 30mm
Bottle Length > 100mm
Bottle Length < 100mm
Bottle Length < 100mm
6.0 Bottle materials, colourants and additives 6.1 Bottle Materials PET bottle materials specified and used by brand owners in principle should be bottle grade PET. Different grades of PET that have slightly different intrinsic viscosities such as those used for water, hot-fill and carbonated do not affect recyclability. It is neither the aim of these guidelines to challenge the choice for PET or any alternative materials under development nor to stifle innovation. New development in plant based PET has no impact on the recycling stream, as the PET material has not changed. The only change has been that the source of ethylene is plant based, however the resin is polymerised and manufactured in exactly the same way, therefore if traditional PET and plant based PET is mixed in the recycling it will not cause any problems as there will be no difference in the materials. The development in the PET „PlantBottle‟ resin now in use or planned to be in use by companies like Coca-Cola, Danone and Heinz has been well communicated to the packaging and recycling industry as can be seen in the following diagram.
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Figure 3. Example of a well communicated change in PET resin with no impact on recycling of PET bottles
6.2 PLA Bottles Materials that closely resemble PET such as PLA will cause significant problems in the PET recycling stream even at very low levels (<0.1%). NIR sorting technology is currently the only viable method for separation of PLA products from the PET recycle stream. However if PLA becomes present in the PET stream in increased levels it is expected that yields of recycled PET will be reduced. The sorting costs for most recycling plants are expected to increase by approximately €1 million per plant. The vol ume of recovered PLA will initially be small whilst PET recovery will continue to increase from its current levels of 1.3 million tonnes. Any separated PLA will be ejected as waste and mixed with PVC and PS. PLA has a low melting point and will start to soften at 60 deg C and melt at temperatures above 170 deg C to form a low viscosity “glue”. PLA flakes in the PET stream become tacky at PLA‟s glass transition temperature. PET is dried at temperatures of 160 C for periods of 4-6 hours. PLA will melt during air drying or flake decontamination creating flake clusters and in some cases situations many flakes stuck together stopping flow, resulting in a blocked or “Solid” Dryer. These clumps can result in sever blockages of outlets and also at restricted areas such the feed throats of extrusion systems. During processing, PLA is incompatible in PET and will form a separate phase in the PET resin. This will mean:
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PLA causes haziness in RPET products
PLA affects PET reprocessing equipment
Sticking of PET pellets in crystalliser or dryer due to exclusion of PLA from the crystallisation of PET
Recycling infrastructure for PLA recovery or recycling is limited PLA bottles are only compostable in industrial composting systems NOT in home composters
PLA is difficult & costly to separate from PET and increases PET recyclate losses
NAPCOR & PETCORE have rejected the recycling of PLA along with PET
A recent evaluation report commissioned by Petcore has found that PLA in RPET at levels even lower than 0.1% (1 bottle in a 1,000) will make any RPET resin unsuitable for most applications and thus dramatically reduces PET‟s recycle value (Petcore, 2009).
Figure 4. An example of PET plaques showing haze (crystallinity) and discolouration due to PLA contamination (Where: Sample C = 0% PLA i.e. control and Sample D = 1% PLA test (Source: PTI Europe, 2006)
Currently the presence of PLA products in the recycling stream can be considered to be somewhat analogous to the presence of PVC. Similar to PVC, PLA can visually appear to be very similar to PET and it is not separated from PET in a float/sink stage. Consequently at even low levels it will cause significant loss of properties and performance of the final recycled PET material. This scenario is distinguished from Polypropylene or Polyethylene products where PP and PE containers are readily separated from PET with very high efficiency by NIR sorting and also by virtue of their lower density in the sink-float density separation process.
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6.3 PVC & PS Bottles Materials such as PVC and PS should not be used under any circumstances for bottle packaging. PVC
and PS sink together with PET in wash and sink-float tanks and are difficult to eliminate. PVC degrades at the temperatures that PET is processed and evolves hydrochloric acid gas, which is corrosive and attacks PET polymer chains causing chain scission and degradation as well as corroding processing equipment. Small amounts of PVC can significantly reduce the intrinsic viscosity of PET. Due to the degradation caused by PVC, RPET resins become discoloured to unacceptable yellow or dark brown colour and the dechlorinated PVC becomes brittle and creates black specs within the RPET resin.
6.4 Clarified PP Materials for Bottles PP bottles are already present in the market place, but currently don‟t compete with PET in the food and beverage market. PP resin is primarily used for household, personal care and industrial containers. PP does not have negative impacts on the PET recycle stream and recycling processes as it can effectively separated via a combination of NIR sorting and density (sink-float) separation techniques. Bottle Material Recycle Friendly
Conditional
Problematic for Recycling
PET RPET
N/A
PLA PVC PS
6.5 PET Colourants & Fillers The recovery of clear PET facilitates the creation of the highest value recyclate and typically allows for closed loop bottle-to-bottle recycling. The use of colourants should be minimised as much as possible. Translucent tints that are very light shades of blue or green are acceptable, as these colours alter the colour of recycled PET in a minor way and help to offset any yellowing that may occur during the recycling process. Strong tints for example mid to dark-blue, green and brown should be avoided whenever possible. Where strong colours are contemplated for shelf appeal then consider using alternative methods like sleeves, however these must be easily separated from the bottle prior to any automatic sorting operations. (Please see section 9 ). Tints are always preferable to opaque colours as they can become dispersed and do not cause haziness in recycled PET as opaque colours do. Black colour should be avoided where possible. Black coloured plastics are difficult to sort unless the black colourant is NIR detectable. Very small amounts of black colourant can significantly discolour a stream of clear / light blue PET recyclate.
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Coloured PET waste has a lower monetary value than clear (typically 50% lower).
The use of strongly pigmented bottles (black, white and colours) has a significant negative impact on the quality of recycled PET since presence of small amounts of coloured fragments can discolour recycled PET during extrusion.
The presence of coloured PET also increases the losses of clear/light blue PET during flake sorting as for every coloured PET flake a clear PET flake is ty pically lost.
Fillers or masterbatch additives for example titanium dioxide, that can be used for opacity or for lowering the cost and polymer content of the plastic should be avoided or their use minimised. Fillers can change the density of the plastic and can also contaminate the recycled PET stream and impact the clarity of the rPET resin. Bottle Colourants & Fillers Recycle Friendly Clear / natural Light (blue or green) tints
Conditional
Problematic for Recycling
Dark green, brown blue / black if NIR detectable Optical brighteners O2 scavengers; UV stabilisers; AA blockers
Non-detectable Dark, opaque, metallic, solid colourants Any use of fillers. Nanocomposite barrier fillers Bio/Oxo/Photo Degradable Additives
6.6 Direct Printing on PET Bottles In the context of a growing interest for its application, direct printing of PET bottles should be avoided. If direct printing on PET bottles is being considered, then only colours and inks that are removable under hot wash conditions should be used. Any remaining ink on bottle or flake surface will discolour recycled PET resin during extrusion and is likely to be difficult to sort as printed PET bottles/flakes may still appear transparent to sensors depending on level of ink coverage.
Inks (Direct print) Recycle Friendly
Conditional
Problematic for Recycling
Laser marked production or expiry date Label inks are non toxic Follow EUPIA Guidelines
Ink direct printed production or expiry date
Any other direct printing Large areas direct printed Inks that bleed, toxic hazardous; react with PET
Inks used on labels and sleeves should not bleed into water (inc. caustic hot-wash at 80 C). The EUPIA have published guidelines on inks that can be used on plastic packaging and that are not hazardous or toxic and therefore do not introduce hazardous substances into recycled materials. The APR has developed test protocols for testing labels and sleeves for ink bleeding.
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or
Inks on Labels & Sleeves Recycle Friendly
Conditional
Label inks are non toxic Follow EUPIA Guidelines
Problematic for Recycling Inks that bleed, toxic hazardous; react with PET
7.0 Closures (closure liners & seals) Closures should not interfere with the recycling process and should be recyclable themselves. Ideally polymers with densities less than water i.e. <1g / cm 3 should be used e.g. PP, HDPE / LDPE. Metal closures should be avoided particularly those with retained tamper evident rings, as these can get carried though the whole recycling process and leave residual metal particles in the final rPET product.
7.1 Closure Liners and Seals Closures with no liners are preferred for ease of recycling. Liners where necessary should be retained within the closure and be made of PE, EVA or PP and have a density less than that of water i.e.<1 g/cm 3 so that they can be easily separated by sink/float separation processes. It is highly recommended that PVC liners should not be used due to its decomposition into acidic residues in the recycling process will generate black specks in the resin as PVC degrades at the processing temperatures used for PET. PVC degrades to carbon char giving off hydrochloric acid (HCl) in the process. The HCl also breaks down the polymer chain length or Intrinsic Viscosity (IV) of PET and corrodes metal processing equipment. Foil safety seals that leave remnants of foil and / or adhesives should be avoided. Sports cap seals should be made from elastomeric materials such as EVA (density < 1g/cm3). Silicone rubber with a density > 1 g/cm 3 should be avoided, the silicon can often be separated from the closure during grinding. Natural coloured silicone is particularly difficult to separate from rPET due to the similar colour of the flakes. Newly developed floating silicone valves or foamed silicone valves that have a density lower than 1 g/cm 3 are acceptable and should not impact PET bottle recycling. The Technical Committee of the European PET Bottle Platform (EPBP) has evaluated the effect of APTAR Food+Beverage closures containing a silicone valve with a density of 0,95 g/cm3 on the quality of recycled PET. Data supplied from tests carried out demonstrated that APTAR silicone valves floated on the washing water, and were thus removed during the sink-float step. The resultant recycled PET flakes did not contain any silicone.
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or
The EPBP concluded that APTAR Food+Beverage swimming silicone valve with a density less than or equal to 0,95 g/cm3 will have no negative impact on current European PET recycling (EPBP, 2010). Therefore, all materials with a density greater than 1 g/cm 3 will sink along with the PET flakes in a sink/float separation unit and will therefore be carried through the process ultimately contaminating the PET. Materials with a density of less than 1 g/cm 3 will float and are removed from the system with the lighter olefinic fraction. Closure Liners & Seals Recycle Friendly
Conditional
Materials density > 1 g/cm 3 Metals / PS / PVC
HDPE / LDPE / PP HDPE / PE+EVA / PP Foamed Silicone / PET
Problematic for Recycling
Paper / silicone „swimming‟ valves (density <1g/cm 3)
Neck Foils Metal / PVC / EVA Silicone (density > 1 g/cm 3)
8.0 Labelling systems & materials Labels should be able to physically detach from the bottle and separate from the PET flakes by specific gravity in flotation tanks or air separators. They s hould not leave adhesive residues on the bottles. Labels which best do this in the recycling process are orientated polypropylene (OPP) roll-fed labels that use a minimal amount of adhesive and expose a significant portion of the PET bottle are most acceptable. Metallised or foil labels should be avoided as they may cause the bottle to be ejected to waste by metal detectors; labels with deposition techniques that provide a very thin layer of metal may be acceptable but need validation. Metallised paper labels although not ideal, are always preferred to decorative and safety foils often used on bottles together with labels. If decoration or safety/tamper proof evidence is needed it is best to use polyolefin based stretch sleeves or paper labels. PS / PVC and PLA shrink sleeves should not be used.
8.1 Paper Labels Paper labels become wet and are often readily removable from PET bottles. However the removal efficiency is highly dependent on the types of adhesives used on the paper label. Any paper fibre that remains stuck on the PET flake will burn during drying and extrusion and will contaminate the RPET granules with black specs from the carbonised paper fibre residues. The use of self-adhesive or pressure sensitive paper labels is less desirable as remaining paper fibres can lead to surface defects and very small, sometimes microscopic holes known as pinholes during blow-moulding of bottles using the recyclate.
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Labelling Systems & Materials Recycle Friendly Conditional HDPE / MDPE / LDPE / LLDPE Wraparound paper labels / PP / OPP / EPS Metallic foils Wraparound plastic
Problematic for Recycling Pressure sensitive / selfadhesive labels. PVC / PS / metallised.
9.0 Sleeving systems LDPE stretch sleeves that cover less than 40% of the length of the bottle body are the best choice and very acceptable to recycling. Stretch sleeves don‟t need to be heated and save energy. Stretch sleeves provide good print characteristics and being PE based, once granulated, are readily removed during sink-float and hydrocyclone density separation stages. Full body shrink sleeves should ideally be made from OPP (the performance of PE stretch sleeves has improved) and still reveal a significant amount of the base PET bottle to allow near-infrared (NIR) spectroscopic identification by automatic sorting systems. Some NIR systems have specific programmes that can recognise fully sleeved bottles of a particular type, pattern or print. Overall, sleeves should be designed to be readily removable in recycling processes i.e. perforated, so that they are dislodged from the PET bottles during the collection, baling and debaling processes in the recycling operations. Shrink sleeves from Polystyrene, PLA, PET-G and PVC (which sink in water along with PET bottle flake i.e. density >1 g/cm 3) should be avoided. PVC is particularly harmful to PET recycling processes as mentioned above. The thickness of shrink sleeves can affect NIR sorting and should typically be kept to less than 40-50 micron thickness. Many bottle manufacturers and brand owners still use sleeves th at are made from PET and in some cases blends of OPS/PET. PVC shrink sleeves are still also used by several manufacturers. Both PVC and OPS are harmful to PET recycling and further due to them being printed the PET sleeves can also contaminate clear PET flake if they end up in the extruder the ink will discolour the RPET and also become dispersed within the RPET resin, potentially contaminating with ink solvents and other chemicals.
9.1 Sorting of Coloured Shrink Sleeves. Coloured shrink sleeves still allow a container to be identified as PET, however due to the sleeve being coloured a clear PET bottle is often sorted into a coloured stream and therefore lost to recycling back into bottles or sheet. This is because the optical sensor will view a bottle with a coloured shrink sleeve as a coloured bottle even though the bottle is actually clear. If shrink sleeves need to be used, designers should carefully consider
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material type and also perforated shrink sleeves which more easily tear during baling and debaling and expose a section of clear PET bottle surface to the optical colour sorters. It is possible to „teach‟ and train sensors to optimise recovery of s leeved items and programmes exist to do this. However it is recommended that PET bottles with full body coloured sleeves include modifications to help recyclers recover this stream into the clear PET fraction. Some suggestions include:
Some sleeve types can be designed to come off the packaging items during the debaling process.
Sleeves can be designed to have a few clear sections to help sort items into clear/natural stream, or
Sleeves can be designed to be removed via design features such as perforations, which tear during baling/debaling and expose natural surface of the packaging item. Sleeves are then removed by air classifiers.
Sleeves can be manufactured with specific „markers‟ that could be used to positively identify the item into clear/natural streams, this approach is very useful when a large volume of this sleeve type is expected in the market place.
A recent review of many MRF‟s and PRF‟s by Nextek showed that often they are currently missing the opportunity to recover greater value from what are clear PET bottles that are sleeved because the sorting systems eject these bottles into the coloured stream. For packaging designers considering using full body sleeves on PET bottles, the following considerations should be explored via trials with sorting equipment suppliers:
Clear PET bottles are typically sleeved with full body sleeves and these are typically coloured and therefore a sorting evaluation is needed to be performed on how the sensors see these bottles in terms of polymer identification and colour recognition. For example, is the underlying intensity of the signal from a clear PET bottle able to always overcome the signal received by the sensor from the sleeve?
If the sleeve is coloured (or multi-coloured) then what decision will the sensor make to sort this bottle into a coloured or a clear stream?
Can a system „learn‟ that a coloured sleeved bottle should be sent into a clear PET fraction stream?
Sleeve thickness can play significant part in detection and newly developed bottles with shrink sleeves should be tested for sorting performance.
Many shrink sleeves are multi-coloured and colour of the sleeve needs to be carefully considered. For example, when a yellow/red sleeve section of a sleeve is presented to the sensor, the sensor will identify it as yellow or red and be able to successfully eject it into a coloured stream. However, if a dark colour or a black sleeve is used it may not be able for the sensor to detect it as black is typically not identifiable by NIR (unless non-carbon black colorant is used).
A combination of black and inappropriate sleeve thickness would result in weak NIR characteristics and not allow the sensor to identify it as a PET polymer bottle or determine its colour.
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Guidelines on sleeve technology for effective removal and sensor classification need to be developed as these will determine sleeve design and manufacture and ultimately help improve the recovery of clear PET bottles with full body coloured sleeves, currently classified as coloured PET bottles.
Sleeves Recycle Friendly
Conditional
Problematic for Recycling
PE Stretch Sleeves preferred PE / PP / OPP / EPS / foamed PET &PET-G (Density < 1g/cm3). Shrink sleeves with perforations and revealing a significant % of the bottle to allow detection of clear PET bottle.
Shrink sleeves with perforations and revealing a significant % of PET bottle; Full body PET shrink sleeves
PVC / PS / PLA / PET-G, other material with density > 1 g/cm 3. Difficult to remove and/or NIR sort with heavy ink coverage.
10.0 Label adhesives The amount of adhesive and surface coverage should be minimised to reduce contamination during recycling. Water-soluble or alkali soluble adhesives are preferred. Adhesives that cannot be removed remain coated to the flakes and can embed undesirable contaminants. The use of thermoset polyurethane adhesives is particularly problematic. The European Plastics Recyclers (EuPR) has issued a list of hot-melt adhesives acceptable for inclusion in mechanical recycling operations (http://www.plasticsrecyclers.eu/docs/docs/useful006.pdf ). Adhesives classified as „good‟ show removal rates of greater than 90%. The Association of Post Consumer Plastic Recyclers (APR) has developed testing protocols to evaluate the impact of adhesives on bottle reclamation systems (http://www.plasticsrecycling.org/technical_resources/testing/pet_flake_contamination_test.asp ). The European PET Bottle Platform(EPBP) has developed testing protocols for adhesive manufacturers and packaging producers to evaluate the impact of adhesive products in conventional PET recycling systems. http://www.petbottleplatform.eu/downloads/public/EPBP_QT504_-_glue_separation_(2010).pdf It is recommended that where possible, the glue be applied in a very thin layer and only act as lap joint. With any new label development designers should perform glue separation tests and check that the label glue is on the EUPR approved glue list, the adhesive should separate from PET flakes during the hot caustic water wash step. Label adhesives should be water soluble or dispersible at temperatures between 60°C and 85°C in order to be removed in conventional washing and separation systems. If adhesives are not removed efficiently, they may disperse and re-deposit on the PET flake regrind and embed unwanted contaminants. The use of “hot melt” adhesives is undesirable and should be avoided unless the adhesive
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readily separates from the plastic and does not cause problems in the reclaiming process. The use of other non soluble adhesive types is discouraged and should be avoided.
Adhesives Recycle Friendly
Conditional
Problematic for Recycling
Water soluble in 60 – 80C Plastic wrap, Minimal glue strip (e.g. lap join). Comply with EuPR guidelines
Strong adhesives with paper labels
Water insoluble (even at elevated temperatures and pH levels)
11.0 Barrier systems (coatings, additives, layers) Monolayer PET packaging with minimal other materials results in the cleanest end-product. There are certain products such as oxygen sensitive juices that require long shelf life protection and the only way to achieve this is with a functional barrier, however reducing the use of barrier layers for products where barrier requirements are minimal is important. Often barrier material amounts are over specified, as a precaution and these high levels of barrier materials impact the recycling stream. There are currently many ongoing developments and innovations in barrier materials and many of these offer enormous growth opportunities for the PET industry, lightweighting opportunities also provide wider packaging options for beverage producers. But the barrier materials are not PET based and the introduction of non-PET material may represent a difficult-to-remove contaminant that could adversely impact recycling. If the new barrier packaging is not designed for recyclability, downstream costs may increase due to the problems with removing the non-PET components. Barriers are typically needed to meet the requirements of specific product applications e.g. protection from either light or oxygen. Barrier materials can be internal, external or middle layers and may be difficult to separate from the PET layers and can therefore hinder recycling. Some barrier systems are more compatible than others in recycling and each system will require a detailed evaluation prior to selection. EPBP issues regular updates of barrier and blocker systems that have passed recyclability tests. In most cases these approvals are conditional, meaning that the use of these materials in PET bottles is limited to a certain weight percentage of the bottle and/or relative proportion of these bottles in the marketplace. This information can be found on EPBP‟s website. In general the use of non-PET layers and coatings are detrimental to the recycling process and should be minimised wherever possible. In some cases using a heavier PET only bottle may still achieve functional and economic objectives without contamination. Where their use is unavoidable they should ideally be easily removable e.g. plasma based coatings (SiOx) or blended additives that are compatible with PET such as Monox. Polyethylene napthalate (PEN) that is less than 3% of the bottle weight or some nylons e.g. MXD6, which can be at least partially separated by mechanical action may be tolerable in some systems. Barrier materials containing EVOH and MXD6 have the potential to cause discolouration during PET recyclate
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reprocessing. Whilst MXD6 does not cause major problems to recycling it does have the potential to cause some discolouration. The Technical Committee of the European PET Bottle Platform (EPBP) in 2010 evaluated the effect of MXD6 co-injected bottles on the quality of recycled PET. The co-injected bottles consisted of a thin layer of MXD6 as the middle layer of a 3-layer construction with no adhesive tie layers and a content of approximately 5% MXD6. Data supplied from tests (carried out according to the EPBP testing protocol) demonstrated that processing conditions and bottle performances were not affected by relatively high percentages of MXD6 coinjected bottles. However, residual colour was found to be a limiting factor, although the MXD6 middle layer was able to be partially removed (by air elutriation) from the inner and outer PET layer during the PET recycling process. EPBP have stated that the co-injected bottles with MXD6 should be used only under the following conditions:
the preform must be injected so that the MXD6 layer is only in the bottle wall with a maximum of 5% Nylon MXD6;
the bottle must be 3-layer construction with no tie layers;
the concentration of these bottles is limited at a level up to 2% in the PET bottle market.
If these conditions are met then based on the assessment‟s outcome and current market‟s knowledge of MXD6 in 2010 the EPBP concluded that Mitsubishi Gas Chemical MXD6 coinjected bottles coating will have no negative impact on current European PET recycling (EPBP, 2010). Therefore, provided that barrier materials such as MXD6 in the PET recycle stream are kept at very low levels then the impacts on recycled PET are believed to be minimal, however if the use of these barrier materials becomes more common or if they start to be used in a product with large volumes then there will be impacts such as discolouration and yellowing of recycled PET. PETCORE have proposed test guidelines to determine the impacts of barrier materials and technologies on the PET recyclate stream and include:
Yellowness Index and determination of flake colour (Doc P-0);
Evaluation of the influence of additives or barrier materials in the production and properties of bottles containing R-PET (Doc P-4);
Evaluation of delamination and removal of barrier materials or additives during the reclaim process (Doc R-1).
11.1
Bio-Oxo-Photo-Degradable Additives A number of companies have started to offer bio-oxo-photo degradable additives for PET bottles. Misleading claims have been made that these additives will help bottles that end up as litter degrade in soil or marine environments. This is not true as PET does not readily degrade, so although the additives may break the bottle structure down, small particles and PET fragments will remain.
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This approach has serious implications as it has the potential to degrade PET materials and have serious impacts on the recycled resins. DEFRA in the UK have published a study stating that packaging containing these additives could cause problems for recycling and that products should be incinerated not composted. µ These additives break down and are believed to leave behind various sizes of PET fragments, which can be highly dangerous to wildlife and result in accumulation of fine plastic particles in the environment. Any bio, oxo, photo degradable additives need to be avoided as they not only do not provide any environmental or functional benefits, they cannot be readily sorted and may be detrimental to the existing recycling infrastructure
12.0 Other Bottle Packaging Components 12.1
Other Components
The use of other components e.g. handles, pouring spouts, sports caps etc is discouraged unless they can be easily separated in flotation tanks (e.g. have a density of < 1 g/cm 3) or are unpigmented compatible materials. Price tags where used should be attached to the closure or the label. The use of RFID tags needs to be individually assessed to ensure that they can be easily removed and separated. Where possible it is best to avoid the use of RFID tags. The use of PVC, PLA and PETG should be avoided wherever possible as these materials significantly interfere with PET recycling systems, since they have an appearance very similar to PET they become included with the PET bottles prior to the recycling process. These materials are of overlapping density (>1g / cm 3) so get carried through the reprocessing system, where due to their lower melting point, they cause the formation of degraded black particles (PVC) and agglomerations of flakes and granules (PLA and PETG) that can ruin many tonnes of otherwise high quality recyclate
12.2 Base Cups Base cups are rarely used on economic grounds and preferably should not be used. However if at any time their use were to be considered then they should be made from HDPE / PP or clear PET and never be made in coloured PET.
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13.0 PET Bottle Recyclability Decision Matrix PET BOTTLE
RECYCLE FRIENDLY
CONDITIONAL
PROBLEMATIC RECYCLING
Colourants, fillers and additives
Clear / natural Light (blue or green) tints
Dark blue / black if NIR detectable Dark green and brown Optical brighteners O2 scavengers; UV stabilisers; AA blockers
Non-detectable Dark, opaque, metallic, solid colourants Any use of fillers. Nanocomposite barrier fillers Bio/Oxo/Photo Degradable Additives
Barrier coatings Blended barrier resins & barrier layers
Clear plasma coatings e.g. CVD* SiOx, Monox Other blended barrier materials that separate and do not cause yellowing
PEN / Amasorb / MXD6 barrier layer (if <3% total bottle weight)
EVOH >3% Amasorb > 5% MXD6 > 5%
Closures
HDPE / LDPE / PP
-
Materials density > 1 g/cm3 Metals / PS / PVC
Closure and seals
liners
FOR
HDPE / PE+EVA / PP / Paper / silicone Foamed Silicone / PET „swimming‟ valves (density <1g/cm3)
Neck Foils Metal / PVC / EVA Silicone (density > 1 g/cm3)
Labels
HDPE / MDPE / LDPE / Wraparound paper labels LLDPE / PP / OPP / EPS Metallic foils Wraparound plastic
Pressure sensitive / selfadhesive labels. PVC / PS / metallised.
Inks
Non toxic Follows EUPIA Guidelines
Inks that bleed, toxic or hazardous; react with PET
Direct Printing
Laser marked production or expiry date
Ink direct printed production or expiry date
Any other direct printing Large areas direct printed
Sleeves
PE / PP / OPP / EPS / foamed PET (Density < 1g/cm3). PE Stretch Sleeves Shrink sleeves with perforations and revealing a significant % of the bottle.
Shrink sleeves with perforations and revealing a significant % of PET bottle; Full body PET shrink sleeves
PVC / PS / other material with density > 1 g/cm 3. Difficult to remove and/or NIR sort with heavy ink coverage.
Adhesives
Water soluble in 60 – 80C Plastic wrap, Minimal glue strip (e.g. lap join). Comply with EuPR guidelines
Strong adhesives paper labels
Water insoluble (even at elevated temperatures and pH levels)
Base cups
No base cup
HDPE / PP / clear PET
Coloured PET and other plastics density > 1 g/cm3
Bottle Size Other components
Diameter > 50mm, Length > 100mm
Diameter 40 -50mm
Diameter < 30mm, Length < 100mm. Any polymer components with density > 1 g/cm3; PVC / PLA / PS / PETG RFID tags
with
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14.0 Contaminants in rPET from poorly designed bottle
packaging Recycled PET is affected by contaminants from poorly designed PET bottles but also many types of packaging products that end up in the commingled packaging waste stream. The following is a list of often found contaminants that regularly end up in recycled PET resins:
Black Specs are found in almost all recycled PET resins. Although RPET resins are melt filtered down to very fine levels (60-100 micron) degraded particles from burnt paper label fibres or degraded PVC black specs break apart and contaminate RPET resins. Black specs are the end result of poorly chosen components such as paper labels or PVC shrink sleeves.
PLA contamination is relatively new in the PET industry, but is a growing threat. PLA is difficult to identify in PET flake and during extrusion will phase separate potentially causing problems during solid stating as the granules with PLA contamination will become tacky. When RPET is processed into bottles any presence of PLA contamination will cause haziness due to induced crystallinity. There are a few PLA bottles present in the EU/UK bottle market, however PLA is becoming popular for thermoformed packaging and PLA labels have now entered marketplace and these will cause problems for PET bottle recycling. PLA labels or sleeves should be avoided for use with PET bottle packaging.
PVC contaminants cause black specs in RPET, discolouration and a drop in the intrinsic viscosity of RPET.
PETG is often mistaken as PET. However PETG has greater melt strength than PET and is often used for wide mouth jars and can cause gels and other processing problems. PETG should be avoided where possible.
PS/OPS/HIPS cause problems for RPET resin during reprocessing and cross contamination with PS/HIPS will often result in bottle defects. Many PET bottle designers still use OPS for sleeves or for labels on PET bottles. Labels or sleeves should be made from polyolefinic materials such as xxxxxxxx?
Silicone contamination has increased due to the popularity of leak resistant silicone valves and also silicone valves in sport drink caps. Silicone valves cause gels and defects in products made from RPET that contains silicone contaminants. Silicone valves should be foamed or have a density less than 1gm/cm 3 or be designed in such a way that once a cap is granulated the silicone floats and is removed with the polyolefinic cap material.
Adhesive contamination results in yellowing of recycled PET. Certain adhesives can also cause the formation of gels and haziness within the RPET resin and products.
Aluminium contaminants found in RPET come from two sources, namely aluminium foils or residual particles from aluminium cans. Aluminium contaminants are usually removed when melt-filtered, however if they get past a filter screen they are seen as serious
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contaminants that result in products being put on hold or recalled. Aluminium components in PET bottle packaging need to be avoided.
Metal contaminants typically from springs in trigger packs or metal closures. These can cause serious problems if they get past a filtration system and result in product recalls or packaging products being put on-hold and re-sorted. Metals need to be avoided in PET bottle packaging.
Coloured PET/Other Coloured Plastics cause discolouration of extruded recycled PET resin. The level of discolouration is typically related to the colour types and the amount of coloured contaminants present. Coloured PET shrink sleeves will be identified as PET and will in many cases contaminate clear PET bottle flakes. Whilst better than PVC/OPS shrink sleeves they will cause discolouration as they often heavily printed and the ink will discolour and contaminate the RPET during melt reprocessing (extrusion).
15.0 Test Protocols for Recyclability 15.1 PET Flake Oven Age test A PET flake oven age test is performed by every recycler. This test allows recycling companies to quickly see what happens to the flake materials before they are extruded and what types of contaminants are present. For example PVC contaminants will degrade and turn brown or black and will therefore be easily identified and their levels measured in parts per million (ppm). The oven aging test is designed to allows QA/QC staff to measure impurities, additives, coatings or glues that discolour during a heating step. Materials with low softening temperatures such as polyolefins and PLA will become tacky and can also be readily identified and their levels measure. In the test, a known quantity of a PET flake sample is heated to 220 °C for 60 minutes. During this thermal treatment, degradation of certain components in the sample will cause the contaminants to discolour, making it possible to be visually detected in the sample. PET flakes with attached glues will become yellow or even brown on surface. After 60 minutes the flake samples are removed from the oven and inspected for discolouration, flakes with glues, degraded materials, clusters due to polymers that become tacky and stick to PET. Some recyclers also measure the L-a-b values of the oven aged flake samples to determine, likely discolouration that may occur during further thermal treatments such as extrusion or solid stating. An oven age test protocol has been developed by EPBP http://www.petbottleplatform.eu/downloads/public/EPBP_QT500_-_oventest_(2010).pdf
15.2 Sink Float Separation Test Protocols A sink-float test can be readily performed by most packaging designers as it typically uses water to separate PET flakes from other components such as caps, labels and closure valves.
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The European PET Bottle Platform (EPBP) organization has developed a test protocol for sink-float testing. Sink floatation is an easy and efficient, density based separation method used to separate light, floating components such as caps and labels from heavy components that sink, such as granulated PET bottles flakes. Non-PET materials and components that sink together with PET flakes cause serious processing inefficiencies which limit the use of rPET in applications such as bottles. Combinations of PET with other material types that sink in water should be avoided on all PET bottle packaging (EPBP, 2010) http://www.petbottleplatform.eu/downloads/public/EPBP_QT502__sink_float_separation_(2010).pdf
15.3 Adhesives – Glue Separation & Removal Test Protocols Where possible the use of glue on PET bottle surface should be avoided, however if this cannot be achieved, soluble glues and small amounts and areas covered should be the objective. The European Plastics Recyclers (EuPR) has issued a list of hotmelt adhesives acceptable for inclusion in mechanical recycling operations (http://www.plasticsrecyclers.eu/docs/docs/useful006.pdf ). Adhesives classified as „good‟ show removal rates of greater than 90%. The Association of Post Consumer Plastic Recyclers (APR) has developed testing protocols to evaluate the impact of adhesives on bottle reclamation systems (http://www.plasticsrecycling.org/technical_resources/testing/pet_flake_contamination_test.as p). The EPBP has developed glue test assessment protocol http://www.petbottleplatform.eu/downloads/public/EPBP_QT504__glue_separation_(2010).pdf These protocols are widely recognised by the recycling industry as they have been developed through direct consultation with many recyclers and have been proven to provide quick and accurate assessments of glue separation.
15.4 Sorting Tests There are currently no specific protocols that specify sorting performance. The European PET Bottle Platform has suggested that NIR and Colour detection accuracy of 80-90% may be acceptable. For many recyclers, sorting performance is the key t o achieving high purity rPET resins. For this reason it is recommended that before new PET bottle packaging is placed into the marketplace it should be checked for detectability by NIR and optical colour sorting systems. All polymers have unique spectroscopic signatures that allow them to be identified and sorted into individual polymer streams. The majority of modern automated sorting systems use Near Infra-Red (NIR) Spectroscopy to identify the polymer type.
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Figure 5. An example of the spectroscopic profile of various polymers
The following picture shows an example of an NIR identification of a medium sized PLA bottle and a larger PET bottle. The sensor is able to distinguish the different polymer types and also the size of the bottles and all the important and necessary information for the ejection of these bottles.
Figure 6. Example of an NIR screen reading showing a signal for a PLA bottle and PET bottle.
Bottle packaging designers also need to consider the impact of different bottle shapes and sizes and how these variables can effect sorting. As previously described, small bottles are difficult to identify especially if covered in large labels or sleeves and can also be difficult to eject. Certain bottle shapes can be difficult to flatten during baling and bottles that are not sufficiently flattened can roll around on the sorting conveyor belt, making identification and detection for the sensor difficult. New developments in sorting include the use of so called laser flake sorting systems which utilise wide spectrum (UV-Vis-NIR-MID) measurement of the polymer spectroscopic signature. Although currently expensive and not widely used, these systems are likely to become more
28
widespread as costs come down. and will be important in sorting of flakes where they are highly effective at removing contaminants such as Silicone, PVC, PLA and other non-PET materials. X-Ray Fluorescence (XRF) systems are occasionally used to help separate PVC from PET as XRF systems can readily detect the chlorine component in PVC. Optical sensors that utilise colour databases and detect in the visible spectrum are used to separate bottles by colour. The majority of recyclers only sort PET into two fractions:
Clear & Light Blue
Mixed Colours (Jazz)
Provided that the volumes of coloured PET justify the investment and infrastructure in sorting equipment, some recently built sophisticated recycling plants sort into coloured PET into a number of colour streams such as:
Clear & Light Blue
Dark Blue
Green
Mixed Colours (Amber, Brown, Yellow, Red, Black, White, Purple, Orange, etc)
It is typically not commercially viable to separate all colours into individual streams. Coloured PET waste streams that contain a mix of colours are diverted away from high value closed loop recycling (i.e. bottle-to-bottle or bottle-to-sheet) and are primarily used for strapping and fibre applications. NIR bottle sorting systems are now capable of sorting mixed materials to high purity rates of 95-98% at high throughput rates of 3-5 tonnes per hour. In Europe a number of specialised NIR bottle sorting equipment manufacturers exist:
TITECH (Germany) http://www.titech.com/
S+S Separation and Sorting Technology (Germany) http://www.sesotec.com/
Pellenc Selective Technologies (France) http://www.pellencst.com/en/
RTT (Germany) http://www.rtt-zittau.de/en/
Binder +Co AG (Austria) http://www.binder-co.com/
BT-Wolfgang Binder GmbH (Austria) http://www.redwave.at
These companies all regularly perform both static and dynamic sorting tests to determine sorting efficiency of newly developed packaging and they can also provide feedback on sort accuracy and achieved purity rates as well as highlight any potential problems before the bottles enter the marketplace and the recycling stream. It is recommended that these suppliers be consulted either directly, via recycling operations or industry bodies such as EPBP, to evaluate new bottle designs. Flake sorting systems have traditionally been used to optically separate clear flake plastic materials from coloured plastic materials. In the last 2 years several companies have
29
developed NIR based flake sorting systems and a wide spectrum laser sorting system has been developed by UNISENSOR. A number of flaking sorting equipment manufacturers based in Europe can perform inhouse tests that may help packaging designers understand potential impacts of bottle design and components on flake sorting performance. The key flake sorting suppliers include:
TITECH Autosort (Flake) (Germany) http://www.titech.com/
S+S Separation and Sorting Technology (FLAKE PURIFIER) (Germany) http://www.sesotec.com/
UNISENSOR Powersort 200 (Germany) http://www.unisensor.de/
ViSys Cleantech (Belgium) http://www.visysrecycling.com/
SEA (Italy) http://www.seasort.com/
Buhler Sortex (UK) http://www.buhlergroup.com/global/en/processtechnologies/optical-sorting.htm
16.0 Conclusions Using these guidelines as a tool to aid the review of current packaging and the development of new packaging will help packaging designers, sales and marketing staff to avoid the use of materials or combinations of materials that might create problems in collecting, sorting or recycling PET bottles. The use of the guidelines will also drive a market change, as more bottles move to highly recyclable categories which will continue to improve the overall quality of recycled PET as well as the quantity of high quality of PET recyclate available for reuse back into bottles. This change will allow more widespread use of rPET at higher incorporation rates and reduce the amount of material that is currently being downgraded due to impurities or poor colour.
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17.0 Key Links, Reports & Organisations The following documents provide guidance on general eco-design principles for PET bottles and other plastic packaging formats. It is recommended that packaging designers become familiar with the key principles discussed within these documents. Whilst there are some differences on the recyclability and categorisation of different packaging, many of these documents outline Best Practices and Industry Standards in PET Plastic Recycling , NAPCOR, 1997 Conception et Fabrication des Emballages en Matiere Plastique pour une Valorisation Optimisee , Chambre Symdicale des Emballages en Matiere Plastique (CSEMP) Design for Recycling Guidelines; Designing Plastic Bottles to be Recyclable , Keith Bechard Entropex Oct 2009, The Association of Postconsumer Plastic Recyclers Designing Recycling-Friendly Plastic Sales Packaging: A discussion paper for Packaging Designers , DKR, Sep 2001 Designing recyclable plastic bottles , Comite Technique de Recyclage des Emballages Plastiques (COTREP) Jan 2004 European PET Bottle Platform: PET Recycling Test Protocol , February 2010, EPBP, www.petbottleplatform.eu Exclusion List for Printing Inks and Related Products , 5th edition Oct 2007, Eupia.org Guidelines on Acceptability of Additives and materials in PET Waste Stream for an Efficient Recycling of PET , Petcore Packaging Design for the Environment: Reducing Costs and Quantities GG360, Envirowise Guide Packaging, Material recycling, report on requirements for substances and materials to prevent a sustained impediment to recycling . CEN 13688, Apr 2000 Packguide: A Guide to Packaging Eco-Design , Incpen, GG908, Envirowise Guide PET Bottles, Design for Recyclability Guidelines , The Association of Postconsumer Plastic Recyclers PET Bleeding Label Test , Testing, Technical Resources, The Association of Postconsumer Plastic Recyclers PET Flake Contamination Test , Testing, Postconsumer Plastic Recyclers
Technical
Resources,
The
Association
of
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Positive Glue List , European Plastics Recyclers (EuPR) Version 1, Approved April 2001 Plastics packaging, Recyclability by Design , Recoup, revised edition 2009 Voluntary Design Guidelines for Designated PET Bottles , Apr 2001, The Council for PET Bottle Recycling
17.1 European PET Bottle Platform The European PET Bottle Platform (EPBP) is a voluntary initiative supported by the European Association of Plastic Recycling and Recovery Organisations (EPRO), the European Plastics Recyclers (EUPR), PET containers recycling Europe (Petcore), the European non-alcoholic beverages association (UNESDA) and The European Federation of Bottled Waters (EFBW). The main objective of the European PET Bottle Platform is to evaluate technologies / products and to allow new PET bottle innovations, while minimising the economic and environmental consequences for the European PET recycling industry. It plans to do so by promoting the recyclability of PET bottles on the market by:
Establishing European harmonised guidelines for PET bottles recyclability that will be accepted across the whole value chain.
Encouraging industry to test new PET bottle concepts and/or materials before market launch according to the harmonised guidelines.
Giving advice and recommendations to the different stakeholders.
Sharing information and knowledge across the whole value chain.
The Platform is grouping technical experts in the field of PET production, design and recycling for an objective evaluation of new technologies and an independent assessment of their impact on the PET recycling processes across Europe. For this, the Platform has established several test procedures in order to assess the recycling profile of new packaging technologies, such as barriers, additives, closures, labels, etc. Products that pass the tests should not experience any problems during recycling. The European PET Bottle Platform has established several test procedures to assess the influence of PET bottle innovations - such as barrier materials, resin formulations, additives and non-PET components in or on PET bottles - on RPET recycling processes. Non-PET components in new or innovative PET bottles may affect specific properties of RPET which are relevant for its re-use as secondary raw material in applications such as bottles, film, sheet, strapping and fibre. The first set of test procedures are relatively rapid and low-cost techniques for the quick assessment of the recycling profile of PET bottles. All quick tests include a complete explanation of the scope, techniques, equipment and test conditions, as well as a “summary interpretation” explaining how to use the test results. The results of the quick tests are purely indicative, and are often used for the optimisation of further tests. EPBP has also developed a test protocol for innovative PET bottles. This protocol is designed to evaluate PET packaging solutions that generally end up in the PET recycling
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stream and that can possibly influence the quality of - or even disturb - the recycling system. Their experts will use the information provided by the applicant, combined with its expertise and knowledge database, to determine the optimal test program, using up-todate testing methods that produce qualitative and/or quantitative test results. Products that pass the tests should not experience any problems during recycling. For further information visit: http://www.petbottleplatform.eu/index.php
17.2 PETCORE PETCORE, PET COntainers REcycling Europe, is a European association fostering the use and development of PET containers and facilitating both PET recycling and the development of recycled end material. Petcore has members from many sectors of the PET industry and today it sees a wide representation from many sectors of the business: resin producers, containers manufacturers, bottle end-users and recyclers. Petcore assists local authorities in establishing PET containers recycling programmes and maintains close relationships with European national associations dedicated to the recovery and recycling of PET containers. Petcore has developed a sound know-how in the establishment of recycling programmes and can assist communities with pertinent information about the processing, reclamation and re manufacture of post-consumer containers. In order to foster PET packaging usage, Petcore believes that PET packaging development, design, promotion and the collection and recycling of post-consumer PET containers, must be based on the three pillars of sustainability. PET packaging development as a whole must therefore be:
economically sound
environmentally justified
socially accepted
For further information visit: www.petcore.org
17.3 APR The Association of Postconsumer Plastic Recyclers (APR) in the USA is the national trade association representing companies who acquire, reprocess and sell the output of more than 90 percent of the post-consumer plastic processing capacity in North America. APR strongly advocates the recycling of all post-consumer plastic packaging. APR promotes development of the plastics recycling industry by providing leadership for long-term industry growth and vitality. APR strives to expand the post-consumer plastics recycling industry through a cooperative effort aimed at identifying and eliminating barriers to successful commercial recycling by:
Developing protocols for the design of packaging for greater recyclability.
Improving the quality of post-consumer plastics entering the system.
Fostering a strong interface with end-user markets.
Promoting a cooperative testing program for new packaging.
Encouraging design for recyclability with guidelines and programs.
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APR‟s Technical Committee has established and updated guidelines for the design, the recyclability and standards for good recycling practices along with researching new technologies. APR also works very closely with other industry organizations such as the National Recycling Coalition, the American Plastics Council and the National Association for PET Container Resources. For further information visit: http://www.plasticsrecycling.org
17.4 NAPCOR The National Association for PET Container Resources (NAPCOR) is the trade association for the PET plastic industry. They promote the introduction and use of PET packaging, facilitate the recycling of PET packaging, and communicate the attributes of the PET container as an environmentally sustainable package. NAPCOR have developed PET recyclability guidelines and provide information on best practices in recycling. For further information visit: http://www.napcor.com/
17.5 UK – WRAP & BRC On-Pack Labelling Scheme for Packaging In the United Kingdom, BRC, WRAP and LARAC all measure the „recyclability‟ of packaging, including PET bottles. The assessment is based on the 3 on-pack label BRC categories: “Widely recycled” means 65% of people have access to recycling facilities for these items. “Check local recycling” means 15% 65% of people have access to recycling facilities for these items. “Not currently recycled” means less than 15% of people have access to recycling facilities for these items. Despite improving household recycling rates in recent years the UK is still lagging behind the continent on recycling. To improve communication the British Retail Consortium (BRC) with support from WRAP, has developed the On-Pack Recycling Label scheme. The OnPack Recycling Label scheme is administered through a subsidiary company called OPRL Ltd (OPRL, 2010). The On-Pack Recycling Label scheme aims to deliver a simpler, UK-wide, consistent, recycling message on both retailer private label and brand-owner packaging to help consumers recycle more material, more often.
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Figure 7. Example of BRC/WRAP On-Pack Recycling Label scheme for PET bottles
Retailers, manufacturers and brand owners who put packaged products on to the UK market are all encouraged to participate in the scheme. Many early signatories are in the groceries sector but the BRC and WRAP aim to cover all consumer packaging going onto the UK market (OPRL, 2010 http://www.onpackrecyclinglabel.org.uk/ ). There is now desire to extend this UK based label scheme to include other areas such as „recycled content‟.
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18.0 References APR 2011, http://www.plasticsrecycling.org/technical-resources/design-for-recyclabilityguidelines BSDA 2009, „Sustainability in Practise: The Soft Drinks Industry Sustainability Strategy – One Year On‟ British Soft Drinks Association, June 2009. European PET Bottle Platform (EPBP) 2010, Swimming Silicone APTAR Valve Assessment http://www.petbottleplatform.eu/downloads/public/4._APTAR_Food+Beverage_swimming_silico ne_valve.pdf European PET Bottle Platform: Sink Float Separation Test Protocol, 2010 http://www.petbottleplatform.eu/downloads/public/EPBP_QT502__sink_float_separation_(2010).pdf European PET Bottle Platform: Glue Separation Test Protocol, 2010 http://www.petbottleplatform.eu/downloads/public/EPBP_QT504_-_glue_separation_(2010).pdf European PET Bottle Platform: PET recycling Test Protocol, 2010 http://www.petbottleplatform.eu/downloads/public/EPBP_protocol_-_website_version_(2010).pdf European PET Bottle Platform (EPBP) 2010, MXD6 Assessment http://www.petbottleplatform.eu/downloads/public/4._Mitsubishi_Gas_Chemical_MXD6_multilay er_-_opinion.pdf Petcore 2006, Protocol to evaluate the influence of PLA bottles on the clear RPET stream Petcore 2008, http://www.petcore.org/content/02182008-study-made-effect-pla-pet-recyclingstream Petcore 2008, http://www.petcore.org/content/021808-petcore-evaluation-polylactic-acid-pla Petcore 2009, http://www.petcore.org/content/09-2009-plaand-its-threat-european-petrecycle-industry Petcore 2011, Protocol‟s evaluating barrier materials, is available from Petcore website once registered, www.petcore.org WRAP 2006, http://www.wrap.org.uk/downloads/Recycling_LCA_Report_Executive_Summary_Sept_2006.8a08 31f3.2839.pdf
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Glossary EVA
ethylene vinyl acetate
EVOH ethylene vinyl alcohol EPS
expanded polystyrene
HDPE
high density polyethylene
LDPE
low density polyethylene
LLDPE linear low density polyethylene MDPE medium density polyethylene MRF
material recycling facility
MXD6 proprietary nylon (barrier material) NIR
near infrared (spectroscopy)
OPP
orientated polypropylene
PEN
polyethylene naphthalate
PET
polyethylene terephthalate
PETG
polyethylene terephthalate glycol
PLA
poly lactic acid
PP
polypropylene
PRF
plastics recycling facility
PS
polystyrene
PVC
polyvinyl chloride
RPET
recycled PET
UV
ultra violet
VIS
visible (spectrum)
XRF
x ray fluorescence
(g) cm
gram centimetre
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