The Authority on Recyclable Plastic Packaging Design
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PET Rigid
(Polyethylene Terephthalate)
- 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.
- The density of PET is 1.38 g/cm3 and therefore it sinks in water.
- Click here to review Product Stewardship Considerations for PET packaging
Base resin is defined as the polymer makeup of the primary body of the package being assessed.
Intrinsic Viscosity (IV)
Intrinsic Viscosity (IV) is one of the parameters that determines application space and processability of a PET resin.
between 0.72- 0.90 dL/g as determined by ASTM D4603 test method
<0.72 dL/g or > 0.90 dL/g as determined by ASTM D4603 test method
When IV of PET resin is low, PET can be brittle and create more fines when the PET is granulated and washed. Also, lower IV causes finished washed PET flake to require longer solid stating times to bring resin up to a targeted IV value required by end users. When IV is higher than stated in guidance, the IV of finished flake may become too high and the resulting high melt viscosity can interfere with molding processes.
Crystaline Melting Point
Crystalline melting point is one of the parameters that determines application space and processability of a PET resin
225-255° C as determined by ASTM D3418-15 test method
<225° C or > 255° C, or non-crystallizable
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. Low melting point is indicative of high comonomer content that could lead changes to in crystallization behavior and diminished properties of recycled PET limiting it’s use in blow molded bottles. 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.
Monomer Composition
> 90% PTA or DMT reacted with MEG
Bis(2-hydroxyethyl) terephthalate, or BHET, is a solid crystalline compound that can be used as a starting material to produce PET, but it is not in wide commercial use. When terephthalic acid reacts with ethylene glycol, BHET is an intermediate that forms early in PET manufacture. Further, BHET is a reaction product that is recovered from glycolysis of chemically recycled PET.
PET co-polymers made with BHET can meet this composition requirement. To evaluate, simply convert the BHET employed to the equivalent starting mass of terephthalic acid and ethylene glycol.
Purified monomers used to produce PET can be derived from petroleum, renewable sources or from chemically recycled waste PET.
< 90% PTA or DMT reacted with MEG
A wide variety of polyester copolymers can be made commercially. A common outcome of making copolymers is that the desirable crystallinity associated with PET is substantially reduced, or even eliminated. Such copolymers may become viscous and sticky like an adhesive at temperatures used to dry recycled PET washed flake. The viscous and sticky behavior results in formation of clumps of PET flake. These clumps are highly undesirable because they can block screens in materials handling systems and can adhere to the inside of driers interfering with drier performance.
Contains polymer blends of PET and other materials
Requires Testing
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.
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PET-CG-01 Critical Guidance Protocol for Clear PET Resin and Molded Articles
Adding colorant to packaging can impact NIR sortation and color, which both impact the disposition and value of the final recyclate.
Clear
APR Design 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 Blue
APR Design 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.
Transparent Green
APR Design Preferred
Green material has significant volume in the marketplace and may comprise up to 15% of the PET bale. The reclaimer may process it into a value added product, or send it to another reclaimer dedicated to green material. Its value is second only to clear material.
Other Transparent Colors
Detrimental to Recycling
Other transparent colors are used for PET bottles containing specialty beverages, supplements, personal care and automotive products. These may be sorted as PET and processed into lower value, dark colored fiber or sheet products.
Opaque/White
Detrimental to Recycling
The impact of white/opaque color is that it typically contains titanium dioxide pigment. This pigment creates an undesirable haze in clear PET. The colorants used to make a white/opaque PET bottle cannot be removed in the PET recycling process, which results in undesirable colors and a low-value recycled PET.
Black/Dark Color
Black/Dark Colors passing SORT-S-01
Recent innovations in both dark/black colorants and sortation technology have created the possibility of sortable dark/black PET containers. However, markets for black PET containers remain limited. Dark/black PET container must be tested using SORT-B-01 and pass to be considered Detrimental.
Black/Dark Colors not passing SORT-S-01
SORT-S-01 test indicates whether or not a plastic article has the potential to be sorted properly under production conditions by Near Infared (NIR)Sortation. For this equipment to operate effectively it must accurately identify the plastic article and direct it to the correct location. If packaging does not pass testing then NIR cannot identify the article and it is either directed to the waste stream or becomes a contaminant in another recyclable stream where it is likely to not be recycled.
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SORT-S-01 Evaluation of the Near Infrared (NIR) Sorting Potential of a Whole Plastic Article
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RES-SORT-01 Near Infrared (NIR) Sorting in the Plastics Recycling Process
Volume, size and shape of package are important features in determining the impacts on the recycling stream. For that reason, this section splits out volume (Large Size Boundary), size (Small Size Boundary) and shape (2D/3D Boundary) based on sortation steps within the recycling process.
Large Size Boundary
This boundary exists due to size limits of recycling machinery, particularly automatic sorting equipment, within a Material Recovery Facility (MRF).
≤ 7.5 liters (2 gal) in volume
> 7.5 liters (2 gal) in volume
Automatic Sorting Equipment at the MRF is not large enough to accept items larger than 7.5 liters . 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 including PET either negatively affect or are lost by the polyethylene processing.
Small Size Boundary
This boundary exists due to the minimum sieve size within the glass screens at a MRF. The mixed material that enters the MRF to be sorted is first compressed/crushed and then passed over these glass screens. The glass screens have small sieve openings where the crushed glass drops through and is sent to the glass recycling stream. However, small plastic packaging items that are below these sieve openings in the glass screens will also drop through to the glass stream and will be lost to the plastic recycling streams.
> 2 in (5 cm) in any two dimensions
≤ 2 in (5 cm) in any two dimensions
The industry standard glass screen size for North American MRFs potentially loses materials less than 5 cm (2 in) to the glass stream. Sortation testing can determine the impact of the size of a container on sortability.
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SORT-S-02 Evaluation of the Size Sorting Potential for Articles with at Least 2 Dimensions Less than 2 Inches
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RES-SORT-02 Size Sorting in the Plastics Recycling Process
2D/3D Boundary
This boundary exists due to the separation process that happens in a Material Recovery Facility in order to separate out the paper (2D items) from the containers (3D items) within the stream of mixed materials. If plastic packaging is sorted by the machinery as 2D, it will be sent to the paper stream and will be lost to the plastic recycling stream.
Smallest uncompressed packaging dimension ≥ minimum dimensions per APR-RES-SORT-05
Smallest uncompressed packaging dimension < minimum dimensions per APR-RES-SORT-05
Aside from not being captured in the PET stream, non-conforming items that are more “flat” can cause contamination in the paper stream. If items are not captured and directed into the PET stream, they are not recycled. SORT-S-05 can determine if packaging is Preferred or Detrimental.
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SORT-S-05 Evaluation of the Two Dimensional/Three Dimensional (2d3d) Sorting Potential of a Whole Article
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RES-SORT-05 Determining Packaging Dimensions that Require 2d3d Sortation Testing
Closures, Closure Liners and Safety Seals should be made from materials that do not negatively impact the final recyclate quality. Material can either be compatible with the base resin or separate in the sink/float process from the base resin. APR recommends caps/closures remain attached to the package when entering the recycling stream. See APR Caps On FAQs.
Polyolefin Closure
Polyolefin closures can be made of PP, HDPE, LDPE , PE copolymers include TPO’s and EVA and TPE elastomers.
All components of closure float in water per PET-S-05
Since these polymers have a density ≤ 1.0 g/cm3 they float in water and are most easily separated from the PET bottle which sinks in conventional separation systems. Additionally, the PET recycling process captures floatable polyolefin to create an salable side stream of marketable material.
Any component of closure sinks in water per PET-S-05
If a component of a closure sinks it will become mixed with recycled PET flake. PET-CG-02 can determine if that the sinking material interferes with PET recycling.
Non-polyolefin Closure
Made with or contains PVC
PVC sinks and is extremely hard for the recycler to remove, particularly in small pieces. The recycled PET stream is very intolerant of even minute amounts of PVC.
Sink in water after granulation per PET-S-05
Non-polyolefin materials that have a density > 1.0 g/cm3 and sink in water with the recycled PET material and can cause contamination. PET-CG-02 will determine impact to final recycled PET.
Metal Closure
Requires Testing
Some metal components may be of sufficient size to either cause rejection at a metal detector, or steel closures may cause a package to be removed by a magnet. In these cases, the package is sent to a waste stream and not recycled. If a metal closure does not impact metal detectors or magnets, it is categorized as detrimental because metals sink with the PET and are difficult to remove from the washed PET flake. Testing can determine impact on recyclability.
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SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components
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RES-SORT-03a Metal Sorting in the Plastics Recycling Process
Other Closures
Requires Testing
All other closures not covered in closure design feature cards needs testing to determine impacts on recyclability
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PET-CG-02 Critical Guidance Protocol for Clear PET Articles with Labels and Closures
Polyolefin Liner/Safety Seal
Polyolefin liners and safety seals can be made of PP, HDPE, LDPE , PE copolymers include TPO’s and EVA and TPE elastomers.
Floats in water per PET-S-05
Since these polymers have a density ≤ 1.0 g/cm3 they float in water and are most easily separated from the bottle in conventional separation systems. Additionally, the PET recycling process captures floatable polyolefin to create an ancillary stream of marketable material.
Sinks in water per PET-S-05
If a liner/safety seal sinks it will become mixed with recycled PET flake. Testing with PET-CG-02 can demonstrate that the sinking material does not interfere with PET recycling.
Removable Liner/Safety Seal
APR Design Preferred
Closure liners that are designed to be completely removed and discarded by a consumer prior to opening the package and are shown to perform as intended in actual use, may be made with any material.
Non-Polyolefin Liner/Safety Seal
Made with or contains PVC
PVC sinks and is extremely hard for the recycler to remove, particularly in small pieces. The recycled PET stream is very intolerant of even minute amounts of PVC.
Sinks in water per PET-S-05
Non-polyolefin materials have a density > 1.0 g/cm3 and sink in water with the rPET material and can cause contamination. PET-CG-02 will determine impact to final rPET.
Liner/Safety Seal containing Paper
Detrimental to Recycling
These materials will contaminate wash water, will contribute to waste disposal costs, or will stick to the saleable closure material or valuable PET and reduce quality and value of the final products.
Liner/Safety Seal containing Metal
Requires Testing
Some metal components may be of sufficient size to either cause rejection at a metal detector, or steel closures may cause a package to be removed by a magnet. In these cases, the package is sent to a waste stream and not recycled. If a metal closure does not impact metal detectors or magnets, it is categorized as detrimental because metals sink with the PET and are difficult to remove from the washed PET flake. Testing can determine impact on recyclability.
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SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components
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RES-SORT-03a Metal Sorting in the Plastics Recycling Process
Spray Dispensers and Pumps should be made from materials that do not negatively impact the final recyclate quality. Material can either be compatible with the base resin or separate in the sink/float process from the base resin.
Polyolefin Dispenser/Pump
Polyolefin dispensers and pumps can be made of PP, HDPE, LDPE , PE copolymers include TPO’s and EVA and TPE elastomers.
All components of dispenser/pump float in water per PET-S-05
Since these polymers have a density ≤ 1.0 g/cm3 they float in water and are most easily separated from the bottle in conventional separation systems. Additionally, the PET recycling process captures floatable polyolefin to create an ancillary stream of marketable material.
Any component of dispenser/pump sink in water per PET-S-05
If a component of a dispenser or pump sinks it will become mixed with recycled PET flake. Testing with PET-CG-02 can determine if the sinking material interferes with PET recycling.
Non-Polyolefin Dispenser/Pump
Made with or contains PVC
PVC sinks and is extremely hard for the recycler to remove, particularly in small pieces. The recycled PET stream is very intolerant of even minute amounts of PVC.
Sinks in water per PET-S-05
Materials with density > 1.0 g/cm3 sink in water with the rPET material and may cause contamination. PET-CG-02 testing will determine impact to PET recycling.
Other Dispenser/Pump
Requires Testing
All other dispensers and pumps not covered in pump/dispenser design feature cards needs testing to determine impacts on recyclability
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PET-CG-02 Critical Guidance Protocol for Clear PET Articles with Labels and Closures
Contains Silicone
Requires Testing
Check valves in spray dispensers or pumps may be made of silicone as an alternative to metals. While polymers are generally preferable to metals, the composition of a silicone part may cause it to be incompatible with PET recycling. PET-CG-02 will determine impact to PET recycling.
Contains metal
Requires Testing
Some metal components may be of sufficient size to either cause rejection at a metal detector, or steel closures may cause a package to be removed by a magnet. In these cases, the package is sent to a waste stream and not recycled. If a metal closure does not impact metal detectors or magnets, it is categorized as detrimental because metals sink with the PET and are difficult to remove from the washed PET flake. Testing can determine impact on recyclability.
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SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components
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RES-SORT-03a Metal Sorting in the Plastics Recycling Process
Barriers, Coatings, Additives and Layers are materials added to to the base resin to improve performance such as enhancing the appearance or processability of a package.
Oxygen Scavengers
Oxygen scavengers are used in PET packaging to extend the shelf life of foods and beverages that are especially sensitive to the presence of oxygen.
Oxygen Scavengers that pass PET-CG-01 when using aging condition per PET-P-12
Untested Oxygen Scavengers
PET packaging that contains oxygen scavenger additives may turn yellow in color during the PET recycling process. The amount of color that forms may be impacted by the age and exposure conditions of the package before recycling. Testing using PET-CG-01 confirms that the additive does not impact PET recycling quality.
Optical Brightner
Detrimental to Recycling
Optical brighteners are not removed from PET in the recycling process and the residual amount can cause unacceptable fluorescence in the next use of the PET resin. The negative impact on the value and quality of the rPET is not detectable until late in the recycling process.
Silicon Oxides
Silicon oxide coatings are used within PET packaging to increase the the barrier properties of the container for CO2 loss in oxygen ingress.
Untested Silicone Oxides
Without testing, there is concern that a coating might interfere with the quality of recycled PET resin and therefore considered Detrimental to recycling.
Silicon Oxides
Testing with PET-CG-01 will determine if the coating interferes with the PET reclaiming process.
Toners
Toners are widely used in PET to mask the appearance of yellow color in the resin.
Untested Toners
Toners with poor thermal stability contribute to the appearance of undesriable yellow color in recycled PET.
Toners
The APR encourages testing of toners using PET-S-03 to select those demonstrated to have better heat stability.
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PET-S-03 PET Heat History and Discoloration Test
Reheat Additives
Reheat additives are widely used in PET to increase the heating rate of preforms prior to blow molding.
Untested Reheat Addtives
Without testing, there is a concern that the reheat additives can impact L value of PET resins makng the resins look dark in color.
Reheat Additives
Reheat additives can turn PET flake dark or yellow, thereby reducing the value and marketability of the rPET produced. Testing using PET-CG-01 can verify their impact.
Degradable Additives
Renders Package Non-Recyclable
See APR Position Paper on Degradable Additives
Other Additives/Barriers
Other untested Addtives/Barriers
Since the impact is unknown, any other additive/barrier that is not tested is considered detrimental to recycling.
Other Additives/Barriers
APR encourages the testing of any additive or barrier technology used with PET packaging to select those with least impact on the PET recycling process.
Labels can interfere with automated sorting as well as impact the quality and quantity of the final recyclate. It is important to consider all aspects of a label such as Surface Area, Substrate, Metal Decoration, Inks and Adhesives when selecting a label.
Surface area coverage is defined as the area of the label divided by the area of the side wall and shoulder of the container. The area of the neck ring, threaded finish and base are not included in the area calculation. The surface coverage area of a label can impact whether or not a package can successfully sorted by NIR and color optical sorters. Label surface area coverage, in conjunction with with substrate, metal decoration, inks and adhesives must be considered when selecting a label.
Main Body Volume ≤ 550 mL
≤ 55% Surface Area Coverage
Containers meeting Preferred Design surface area coverage by a label are expected to sort accurately in both NIR and color optical sorters. Since labels for PET packaging most often become a waste stream, APR encourages labels that are as small in surface area and weight as possible.
> 55% Surface Area Coverage
Labels with high surface area coverage may interfere with NIR detection of the PET container. NIR testing is performed using the SORT-S-01 protocol. In addition, The high label surface area coverage may also cause a clear PET bottle to be sorted as a colored bottle in a color sorter. SORT-S-04 will determine the likelihood of the PET article to be sorted into colored stream with label coverage used. Both tests must be performed in order to determine recyclability cateogorization.
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RES-SORT-01 Near Infrared (NIR) Sorting in the Plastics Recycling Process
Main Body Volume > 550 mL
≤ 75% Surface Area Coverage
Containers meeting Preferred Design surface area coverage by a label are expected to sort accurately in both NIR and color optical sorters. Since labels for PET packaging most often become a waste stream, APR encourages labels that are as small in surface area and weight as possible.
>75% Surface Area Coverage
Labels with high surface area coverage may interfere with NIR detection of the PET container. NIR testing is performed using the SORT-S-01 protocol. In addition, The high label surface area coverage may also cause a clear PET bottle to be sorted as a colored bottle in a color sorter. SORT-S-04 will determine the likelihood of the PET article to be sorted into colored stream with label coverage used. Both tests must be performed in order to determine recyclability cateogorization.
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RES-SORT-01 Near Infrared (NIR) Sorting in the Plastics Recycling Process
The label substrate, in conjunction with surface coverage area, metal decoration, inks, and adhesives, must must be considered when selecting a label.
Polymer Film Label
Film label that floats in water
Film labels that float in water, which are typically polyolefin based, can be easily separated from the PET flake through the sink/float process. However, the use of adhesives and label inks on film label substrate impact the ability of the film to sink or float and must also meet APR Design Preferred criteria in order for the overall finished label to be considered APR Design Preferred. See design feature cards on inks and adhesives.
Film label that contains PLA or PVC
Both materials are extremely difficult to remove in the recycling process due to their similarity in density to PET, which causes them to sink in the float/sink tank along with the PET. Both cause severe quality degradation in the final recycled PET stream even in very small amounts.
Film label that sinks in water
Film labels that sink in water, which are typically non-polyolefin based, will be combined with the PET flake and must be compatible. Testing using PET-CG-02 is required to determine the impact.
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PET-CG-02 Critical Guidance Protocol for Clear PET Articles with Labels and Closures
Paper Label
Detrimental to Recycling
The PET reclamation process involves a hot caustic wash that removes adhesives and other label components. This process renders paper into a pulp which is very difficult to filter from the liquid, adding significant load to the filtering and water treatment systems. Some of the small individual paper fibers will remain with the PET and carbonize when the material is extruded, causing unacceptable quality degradation. Non-pulping paper labels that resist the caustic wash process sink in the float-sink tank, thereby causing RPET contamination.
Metal decoration on labels includes vapor deposited metal films, metal foils, or inks with metallic pigments. Metal decoration content, in conjunction with surface coverage area, substrate, inks and adhesives, must be considered when selecting a label.
Metal Decoration
Label with metal decoration where surface area ≤ Preferred Surface Area per RES-SORT-03b
Labels with metal decoration that are untested OR do not pass SORT-S-03
Without further testing, metal decoration on labels with surface areas above the Preferred Surface Area in RES-SORT-03b are categorized as Non-Recyclable due to a higher probability of being removed by the metal detector during sortation. When packaging is rejected by a metal detector, the package is sent to a waste stream and not recycled.
Labels with metal decoration where surface area > Preferred Surface Area per RES-SORT-03b
Labels that contain metal decoration above the preferred surface areas specified in the RES-SORT-03b would need to be tested using SORT-S-03 to verify they are under the spherical equivalent thresholds.
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SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components
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RES-SORT-03b Metal Decoration Resource
The label inks, in conjunction with surface coverage area, substrate, metal decoration, and adhesives, must be considered when selecting a label.
Label Inks
Label Inks are inks printed onto a label substrate.
Hot Caustic Resistant Ink used on Film Label Substrate that floats in water
Hot caustic resistant inks are inks that remain on the label film when exposed to the hot caustic wash used in PET recycling and do not discolor the wash water. Testing using PET-B-02 will determine if the ink meets critieria to be considered Hot Caustic Resistant. Hot caustic resistant inks are developed for floating labels employed for PET packaging and designed to be compatible with PET recycling.
Wash off Inks used on Film Label Substrate that sinks in water
Wash off inks are inks that wash off the label film when exposed to hot caustic wash water used in PET recycling and do not discolor the wash water. Testing using PET-B-02 will determine if the ink meets critieria to be considered Wash off Ink. Wash-off inks are designed for higher density “sinking” label films where the ink washes off in particles and is designed to be compatible with PET recycling
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PET-B-02 Benchmark Test for Clear PET Articles with Labels and Closures
Direct Print Inks
Direct Print Inks that are printed directly onto PET packaging without the use of label substrate.
Hot Caustic Resistant Ink
Hot caustic resistant inks are inks that remain on package in a direct print application when exposed to the hot caustic wash used in PET recycling and do not discolor the wash water. Testing using PET-B-02 will determine if the ink meets critieria to be considered Hot Caustic Resistant. However, utilizing hot caustic resistant inks directly printed on PET packaging may cause discoloration issues to the recycled PET as it cannot be removed from the flake in wash.
Wash off inks
Wash off inks are inks that wash off the PET package and do not discolor the wash water used in PET recycling . Testing using PET-B-02 will determine if the ink meets critieria to be considered Wash off Ink. Wash-off inks are desired for direct print applications as it can be removed from flake in wash water without contamination.
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PET-B-02 Benchmark Test for Clear PET Articles with Labels and Closures
The label adhesive, in conjunction with surface coverage area, substrate, metal decoration, and inks, must be considered when selecting a label.
Releasing Adhesive
During the washing process at reclaimers, releasing adhesive washes off the PET surface and rinses cleanly from the PET flake so that it is liberated and separated from the PET flake.
Used on Polymer Film Label Substrate that floats in water
Used on Polymer Film Label Substrate that sinks in water
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PET-CG-02 Critical Guidance Protocol for Clear PET Articles with Labels and Closures
Non-Releasing Adhesive
During the washing process at reclaimers, non-releasing adhesive keeps label adhered to PET package and does not allow for separation. Label adhesives, label films and inks can all become sources of contamination in recycled PET.
Used on Polymer Film Label Substrate that floats in water
Used on Polymer Film Label Substrate that sinks in water
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PET-CG-02 Critical Guidance Protocol for Clear PET Articles with Labels and Closures
Paper Attachments
Detrimental to Recycling
The PET reclamation process involves a hot caustic wash that removes adhesives and other label components. This process renders paper into a pulp which is very difficult to filter from the liquid, adding significant load to the filtering and water treatment systems. Some of the small individual paper fibers will remain with the PET and carbonize when the material is extruded, causing unacceptable quality degradation. Non-pulping paper labels that resist the caustic wash process sink in the float-sink tank, thereby causing contamination to the recycled PET.
PS Attachments
Detrimental to Recycling
Polystyrene has a density of > 1.0 g/cm3, so it sinks and remains with the PET in float/sink separation systems. It is not compatible with PET and may cause serious processing and end-use problems.
RFID Attachments
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
Welded Attachments
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 contamination and yield loss issues to recycled PET 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
Metal Attachments
Requires Testing
Some metal components may be of sufficient size to either cause rejection at a metal detector, or steel closures may cause a package to be removed by a magnet. In these cases, the package is sent to a waste stream and not recycled. If a metal closure does not impact metal detectors or magnets, it is categorized as detrimental because metals sink with the PET and are difficult to remove from the washed PET flake.
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SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components
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RES-SORT-03a Metal Sorting in the Plastics Recycling Process
PET Attachments
If polymers used for PET attachments meets criteria listed in Base Resin section
If polymers used for PET attachments contain additives or other non PET materials
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PET-CG-01 Critical Guidance Protocol for Clear PET Resin and Molded Articles
PVC or PLA Attachments
Renders Package Non-Recyclable
Both materials are extremely difficult to remove in the recycling process due to their similarity in density to PET, which causes them to sink in the float/sink tank along with the PET. Both cause severe quality degradation in the final recycled PET stream even in very small amounts.