Due to its clarity and natural CO2 barrier properties, PET is one of the most widely used packaging resins. It is easily blown into a bottle or formed into a sheet, thereby becoming the resin of choice for many applications. PET does not normally have the desired properties for closures, handles, attachments or labels so other polymers are commonly used for these items and affixed to the PET package. PET properties can be enhanced with colorants, UV blockers, oxygen barriers/scavengers and other additives. Each modification and addition to the base, clear PET in a package must be considered for its effect on the recycling stream. Items should either be economically removed from the PET in the typical recycling process or be compatible with RPET in future uses. The density of PET is 1.38 and so it sinks in water. Closures, labels and attachments should be made from materials with a density less than 1.0 that will float in water and therefore be readily separated from the PET.
The APR’s Champions for Change® Program encourages consumer product, plastic package and bottle component manufacturers to work with the APR protocols to determine whether new modifications to a regularly recycled plastic package will negatively impact the recycling process prior to introducing the modification.
*The content below was revised on 10-23-2015.*
- BASE POLYMER
- BARRIER LAYERS, COATINGS & ADDITIVES
- CLOSURES AND DISPENSERS
- LABELS, INKS AND ADHESIVES
- BIO-BASED PET RESIN
- POSTCONSUMER CONTENT
- RESIN IDENTIFICATION CODE, RIC
PET and PET variants resins which have a crystalline melting point between 235 and 255C are preferred.
Materials of a lower melt point or non-crystalline materials often become sticky in the reclaimers’ pre-extrusion dryer when the dryer is operated at PET temperatures and prevent the material from flowing through the process. Materials of a higher melt point remain solid in the reclaimers’ extruder and cause blockages in melt screens. Both conditions greatly hinder the ability of the reclaimer to operate.
Blends of PET and other resins require testing to determine the appropriate APR recyclability category.
Other resins may be blended into the PET to enhance certain properties during the package’s intended first use. The materials’ effect on the RPET in future uses must be evaluated since it will not be removed in the recycling system. The appropriate test protocol is:
Non-PET layers and coatings require testing to determine the appropriate APR recyclability category.
The use of non-PET layers and coatings can be detrimental to recycling of PET if not implemented according to APR test protocols. Layers and coatings must either separate and be removed from the PET in the recycling process or have no adverse effects on the RPET in future uses. When used, their content should be minimized to the greatest extent possible to maximize PET yield, limit potential contamination, and reduce separation costs. Some layers and coatings have been found compatible with PET or are easily separated in conventional recycling systems. Two test protocols are available:
Degradable additives (photo, oxo, or bio) require testing to determine determine the appropriate APR recyclability category.
Recycle PET is intended to be used in new products. The new products are engineered to meet particular quality and durability standards given properties of typical recycled PET. Additives designed to degrade the polymer diminish the life of the material in the primary use. If not removed in the recycling process, these additives shorten the useful life of the product made from the RPET as well, possibly compromising quality and durability.
Degradable additives should not be used without testing to demonstrate that their inclusion will not materially impair the full service life and properties of any product made from the RPET that includes the additive. These additives must either separate and be removed from the PET in the recycling process or have no adverse effects on the RPET in future uses. When used, their content should be minimized to the greatest extent possible to maximize PET yield, limit potential contamination, and reduce separation costs.
The appropriate screening test protocol is:
Additives require testing to determine the appropriate APR recyclability category.
The APR recognizes that other types of additives may be required for the performance of a particular package but are not addressed in this document. Additives such as de-nesting, anti-static, anti-blocking, anti-fogging, anti-slip, UV barrier, stabilizer and heat receptor agents and lubricants should be tested to determine their compatibility with recycling. Of particular concern are additives which cause the RPET to discolor or haze after remelting or solid stating since RPET with poor haze or discoloration is greatly devalued and has limited markets. This is particularly troublesome since it is difficult to identify material with this effect until extremely late in the recycling process where a great deal of added cost has been imparted into the material.
Two test protocols are available:
Optical brighteners are detrimental to recycling.
Like many other additives, optical brighteners are not removed in the recycling process and can create an unacceptable fluorescence for next uses of RPET containing the brighteners. It is difficult to identify material with this negative effect until extremely late in the recycling process where a great deal of added cost has been imparted into a material of low value due to the additive.
Clear unpigmented PET is preferred
Clear material has the highest value as a recycled stream since it has the widest variety of end-use applications. It is the most cost effective to process through the recycling system.
Transparent light blue packaging is preferred
Light blue material is most often included with the clear material stream to act as a bluing agent and offset some yellowing. This not only adds volume to the high value clear stream, it improves its quality when used in limited amounts. Normally it can also be added to the green stream with little negative effect
Transparent green packaging is preferred
Green material has significant volume in the marketplace. At the MRF, it is baled along with the clear PET and may comprise up to 30% of the PET bale. The green material is separated from the clear by the original reclaimer, who may process it into a value added product, or send it to a reclaimer dedicated to green material. Its value is second only to clear material. However, green is not without its issues. Because a consistent, clear color is critical to future products using clear RPET, the recycling process includes a great deal of machinery and manpower dedicated to separating colored material. This adds significant cost to the operation. Even so, small but significant amounts of colored material, including transparent green, pass into the clear stream, thereby affecting the quality of clear RPET. Markets such as clothing, carpet, soft drink bottles and thermoformed sheet depend on very precise colors using clear material as a basis.
Transparent colors other than green and light blue are detrimental to recycling
These colors when separated from the primary clear and green streams are small in volume with little market value. Some reclaimers are able to tolerate transparent amber tinted bottles in their systems but these are limited.
Translucent and opaque colors including white are detrimental to recycling
There is very little market value for this material and it contaminates the other streams that have value. It can also be very difficult for automatic sorters to identify opaque colored polymers so additional labor must be employed to remove opaque materials.
Nucleating agents, hazing agents, fluorescers, and other additives for visual and technical effects are detrimental to recycling
Like many additives, these features are not removed in the recycling process and can affect the value of the RPET and its performance in future uses.
Black color renders the package non-recyclable
NIR sorting technology is not capable of identifying a black polymer and manual sorting cannot distinguish one black polymer from another. Other separation techniques such as float-sink cannot be employed since many black polymers sink with PET. Therefore, black packaging is considered a contaminant for nearly all reclaimers.
Size and shape are critical parameters in MRF sorting, and this must be considered in designing packages for recycling. The MRF process separates items by size and shape first, then by material. Screens direct paper, and similar two-dimensional lightweight items, into one stream; containers and similar three-dimensional heavier items into another steam; while broken glass and smaller but heavy items are allowed to drop by gravity to yet another stream, which may or may not be further sorted. Large, bulky items are typically manually sorted on the front of the MRF process.
Items more two-dimensional than three-dimensional render the package non-recyclable per APR definition.
Aside from not being captured in the plastic stream, they cause contamination in the paper stream. Items should have a minimum depth of two inches in order to create a three-dimensional shape for proper sorting. This issue is unrelated to the polymer type. The APR encourages and anticipates developments in MRF design and technology to improve capture and recovery of thin plastics; however, at the current time this technology either does not exist or is uninstalled in the majority of MRFs.
Items smaller than three inches in all dimensions render the package non-recyclable per APR.
The industry standard screen size loses materials less than three inches to a non-plastics stream, causing contamination in that stream, or directly to waste. These small packages are lost to the plastic recycling stream. It is possible that some small containers travel with larger ones when either the screens wrap with film or they are operated above their design capacity. Film wrapping reduces the effective size of the screen and over-running provides a cushion of large items on which the smaller items travel. The design guidelines use clean screens operating at their design capacity for the determination of the recyclability category. The APR anticipates and encourages technology development to improve the process of small package recovery but currently these items are not recovered.
Items greater than two gallons in volume are detrimental to recycling.
Recycling machinery, particularly automatic sorting equipment, is not large enough to accept items larger than two gallons. Because larger containers jam the systems, most MRFs employ manual sortation before the automatic line to remove the large items. These items are recovered in a stream of bulky rigid containers that are sold and processed as polyethylene since the vast majority of bulky rigid items are comprised of this polymer. Other polymers either negatively effect or are lost by the polyethylene processing.
Polypropylene and polyethylene closures are preferred.
Since these polymers float, they are most easily separated from the bottle in conventional separation systems. Additionally, the PET recycling process captures floatable polyethylene and polypropylene to create an ancillary stream of marketable material. Care must be taken when modifying the polyethylene or polypropylene to ensure the modifier does not increase the overall density to the point it sinks.
Closure systems without liners are preferred.
Due to size and thickness, most liners are lost in the recycling process thereby slightly decreasing yield. Closures without liners do not experience this loss.
EVA and TPE liners in plastic closures are preferred.
Both EVA and TPE float in water and will be separated in the recycling process with the floatable polyethylene and polypropylene. Since EVA and TPE are compatible with these polymers, and in fact enhance their properties, they are preferred.
Closures containing metal or metal foils are detrimental to recycling.
It is difficult to separate from PET compared to the preferred closure systems (polypropylene and polyethylene) and adds both capital and operating costs to conventional reclamation processes. Even a small amount of metal left in the RPET stream will block extruder screens in remanufacturing. Large metal items attached to PET packages may cause the package to be directed to the metal or waste stream in the recycling process, causing yield loss. Small metal components such as spray dispenser springs unravel in the recycling process and blind screens, adding significant cost for removal at the end of the process.
Two test protocols are available:
Screening test: An APR test to delineate between metal items which render the package non recyclable per APR Definition and metal items that are detrimental to recycling is anticipated for 2017.
Definitive Test: Closure Test
Closures made from polystyrene or thermoset plastics are detrimental to recycling.
Both materials are heavier than water and sink in the float-sink tank with PET. They are extremely difficult to separate from RPET flake, requiring a costly and inexact polymer flake sorter currently not installed in many reclaiming operations.
Closures containing silicone polymer are detrimental to recycling.
Silicone sinks in the float-sink tank with the PET and is difficult to remove with other methods, thereby causing contamination in the final product.
The use of PVC closures or closure liners render the package non-recyclable per APR.
PVC sinks and is extremely hard for the recycler to remove, particularly in small pieces. The recycled PET stream is very intolerable to even minute amounts of PVC.
Removing adhesives is a significant component to the cost of recycling. The most recyclable packages use the lowest quantity of recycle-friendly adhesive. Lower adhesive usage reduces processing cost and potential contamination risk.
Polypropylene or polyethylene labels with a specific gravity less than 1.0 are preferred.
These materials float in water so they are separated from the PET in the float-sink tank with the closures. Since they are the same general polymer as most of the closures they do not contaminate or devalue this stream. Care should be taken to ensure that any modifiers to the label material do not increase its density above 1.0.
Laminated labels require testing to determine the appropriate APR recyclability category.
Labels that break into small, very thin pieces of material are more difficult to manage in the recycling process because they behave erratically in a float-sink tank. Therefore labels that stay intact are preferred. Carry-over of delaminated labels into the RPET can result in contamination.
One Test protocol is available:
- Link to New Delamination Test [NOTE: document under development]
Full bottle sleeve labels require testing to determine the appropriate APR recyclability category.
Full bottle sleeve labels cover a large amount of the bottle surface with a polymer that is not the same as the bottle body. Because of this, a sleeve label designed without considering recycling may cause a false reading on an automatic sorter and direct a PET bottle to another material stream where it is lost to the process. Furthermore, some sleeve label materials cannot be removed in the recycling process and contaminate the RPET produced. Sleeve labels that have been found compliant with the APR test protocols should be selected.
One test protocol is available:
Pressure sensitive labels require testing to determine the appropriate APR recyclability category.
Pressure sensitive labels generally require complete adhesive coverage which is greater than other typical label methods. This raises the importance of the compatibility of the type of adhesive with the recycling process. Adhesives resistant to washing in the recycling process allow labels to remain on the PET and become contaminants in the final product. Adhesives that have been found compliant with the APR test protocols should be selected.
Two test protocols are available:
Polystyrene labels require testing to determine the appropriate APR recyclability category.
While PS labels are tolerated by some PET reclaimers, PS has been identified as causing seriousprocessing and end-use problems by others and should only be used if it can be easily and completely removed from the PET in conventional separation systems. PS inherently sinks in water due to its density so it travels with the PET in the recyclers’ float-sink systems. However, expanded PS may float and in this case it may be less of a problem to the recycler.
One test protocol is available:
Label structures that sink in water because of the choice of substrate, ink, decoration, coatings, and top layer require testing to determine the appropriate APR recyclability category. The reclaimers rely on float-sink systems to separate non-PET materials. Label components that sink with the PET end up in the RPET stream as contaminants.
One test protocol is available:
Paper labels are detrimental to recycling (for pressure sensitive paper labels reference the pressure sensitive label category).
The PET reclamation process involves a hot caustic wash that removes glue and other label components to the levels required to render the RPET usable. Paper, when subjected to these conditions, becomes pulp which is very difficult to filter from the liquid, thereby adding significant load to the filtering and water treatment systems. Individual paper fibers making up pulp are very small and difficult to remove so some travel with the PET. Paper fibers remaining in the RPET carbonize when the material is heated and remelted, causing unacceptable quality degradation. Non-pulping paper labels that resist the caustic wash process sink in the float-sink tank, therby causing RPET contamination.
Metal foil labels are detrimental to recycling.
Sorting equipment in the recycling process is designed to detect and eliminate metal from PET. Even very thin metallized labels may be identified as metal by the sorting equipment and cause the entire bottle to be rejected as waste, thereby creating yield loss. If not detected, they pass through the process with the PET and cause contamination issues in the RPET.
PVC and PLA labels render the package non-recyclable per APR.
Both materials are extremely difficult to remove in the recycling process due to their similarity in density to PET. Both cause severe quality degradation in the final recycled PET stream even in very small amounts.
Adhesives require testing to determine the appropriate APR recyclability category.
Adhesives that wash off cleanly from PET and remain adhered to the label are preferred. Label adhesive that is not removed from PET, or which redeposits on the PET during the wash step is a source of contamination and discoloration when PET is recycled.
The recycling process is designed to remove reasonably expected contamination from the surface of the PET to a degree necessary to render the RPET economically reusable in further applications. Adhesives that are resistant to this process are detrimental to recycling since they remain on the PET throughout the process, thereby becoming a contaminant in the final product.
Three test protocols are available:
Non-water soluble/dispersible adhesives are detrimental to recycling. These adhesives are not removed in the recycling process to the degree required to make material of acceptable quality. They cause contamination and quality problems.
Label inks require testing to determine the appropriate APR recyclability category. Some label inks bleed color in the reclamation process, discoloring the PET in contact with them and significantly diminishing its value for recycling. The APR and NAPCOR have developed a testing protocol to assist label manufacturers in evaluating whether a label ink will bleed in conventional PET reclaiming systems. Label inks must be chosen that do not bleed color when tested under this protocol. Two screening test protocols are available:
See the definitive test for the appropriate label type
Direct printing other than date coding requires testing to determine the appropriate APR recyclability category. Historically, inks used in direct printing tend to bleed or otherwise discolor the PET during the recycling process, or introduce incompatible contaminants. In either case, the value of the RPET is diminished. Some inks used in direct printing do not cause these problems. The specific ink must be tested to determine its effect. Three test protocols are available:
Clear PET attachments are preferred.
Attachments made of the base polymer are recovered and recycled with the base polymer without causing contamination or yield loss, thereby generating the highest value.
Tamper evident sleeves and safety seals require testing to determine the appropriate APR recyclability category.
If tamper resistance is required in specific product applications, it should be an integral design feature of the bottle. The use of tamper-resistant or tamper-evident sleeves or seals is discouraged as they can act as contaminants if they do not completely detach from the bottle, or are not easily removed in conventional separation systems. If sleeves or safety seals are used, they should be designed to completely detach from the bottle, leaving no remains on the bottle. The material used should float and separate from the PET in the float-sink system. Two test protocols are available:
Non-PET attachments such as handles require testing to determine the appropriate APR recyclability category.
These should not be adhesively bonded to the package and should readily separate from the package when ground. They should be made from materials that float in water such as PP or HDPE. If adhesives are used to affix attachments, their selection should consider the adhesive criteria within this document. Two test protocols are available:
Metal and metal containing attachments are detrimental to recycling.
Examples include metal foils and metalized substrates that sink in water as well as metal sprayer balls and springs. In the recycling process these items are either identified and removed along with their PET component in the early stages, thereby causing yield loss, or they pass into the recycling process causing a contamination issue. Since they are heavier than water they sink with the PET in the float-sink tank. Many of these items are too small to be removed with machinery designed to remove metal such as eddy current and optical separators. Springs in particular unravel and become entangled in filtering screens throughout the recycling process.
*An APR test to delineate between metal items which render the package non recyclable per APR Definition and metal items that are detrimental to recycling is anticipated for 2017.
Paper attachments are detrimental to recycling
The PET reclaimation process uses a hot caustic wash to remove glue and other contaminants to the levels required to render the RPET usable. Paper, when subjected to these conditions, becomes pulp which is very difficult to filter from the liquid, thereby adding significant load to the filtering and water treatment systems. Individual paper fibers making up pulp are very small and difficult to remove so some travel with the PET. Paper fibers remaining in the RPET carbonize when the material is reused causing unacceptable quality degradation.
Base cups are detrimental to recycling.
Base cups reduce PET yield and increase separation costs. If base cups are used, the use of unfilled HDPE or clear PET is preferred to all other materials. If glued on, base cup adhesives should be water soluble or dispersible at 140 °F to 180 °F in order to be removed in conventional washing and separation systems. Adhesive usage and surface area covered should be minimized in order to maximize PET yield and avoid contamination.
Welded attachments are detrimental to recycling.
A certain amount of a welded attachment cannot be separated from the PET in the recycling process. These attachments, even when ground and made of floatable materials, cause RPET contamination and yield loss issues in both cases: when the PET they are attached to causes the ground section containing both polymers to sink, or when the ground section floats.
RFID’s (radio frequency identification devices) on packages, labels or closures are detrimental to recycling.
Unless they are compatible with PET recycling and are demonstrated not to create any disposal issues based on their material content, the use of RFID’s is discouraged as it limits PET yield, introduces potential contamination, and increases separation costs.
PVC and PLA attachments of any kind render the package non-recyclable per APR.
The use of PVC or PLA attachments of any kind on PET packaging is undesirable and should be scrupulously avoided. This includes thermoforms of PVC and/or PLA that may be visually confused with PET thermoforms. Very small amounts of PVC or PLA can severely contaminate and render large amounts of PET useless for most recycling applications. In addition, PVC and PLA are very difficult to separate from PET in conventional water-based density separation systems due to similar densities (densities greater than 1.0) that cause both to sink in these systems.
The use of bio-based PET resin, in which the MEG component is sourced from biological materials such as sugar cane residue or similar materials, are fully compatible with petroleum-based PET in the recycling process. Bio-based PET should not be confused with PET containing bio- or oxo-degradable additives.
The use of postconsumer PET in all packages is encouraged to the maximum amount technically and economically feasible.
Use the correct Resin Identification Code symbol of the proper size as detailed in ASTM D7611 is encouraged.