HDPE Rigid - Natural Archives - Association of Plastic Recyclers (APR)

Base resin is defined as the polymer makeup of the primary body of the package being assessed.

Blend Density

Density is an important property and float-sink tanks are critical separation tools used by reclaimers. Many fillers, pigments and additives used with PE have higher densities and when incorporated into PE can increase the density of resulting PE blend causing it to sink in the float-sink tank. When a PE item sinks during reclamation, the item is lost as waste reducing yield, increasing cost, and thus will be categorized as non-recyclable. The density of an item can be calculated or measured via ASTM D792, ASTM D1505 or ISO 1183-1.

Between 0.941-0.970 g/cm³

≥ 1.0 g/cm³ or < 51 wt% of PE blend floats per O-S-01

> 0.970 g/cm³ and <1.0 g/cm³

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Melt Index

Between 0.20 – 1.61 g/10 min per ASTM D1238

< 0.20 g/10 min or >1.61 g/10 min per ASTM D1238

Extrusion blow molding (bottles) and extrusion (pipe) are the two largest volume applications for recycled HDPE. Both applications require melt flow index and density within the Preferred range for processability and mechanical performance required for the applications.

Blends of HDPE and Other Resins

Requires Testing

Other resins may be blended into the HDPE to enhance certain properties during the package’s intended first use. The materials’ effect on recycled HDPE in future uses must be evaluated since it will not be removed in the recycling system. Testing using HDPE-CG-01 can determine impacts.

Test Protocols

HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Adding colorant to packaging can impact NIR sortation and color, which both impact the disposition and value of the final recyclate.

Unpigmented

APR Design Preferred

L value < 40 or average NIR reflectance is ≤ 10%

Requires Testing

L values ≤ 40 or an average NIR reflectance ≤ to 10% have a high probability of not being recognized by NIR correctly and the packaging will either be sent to the wrong plastic resin stream creating contamination or be sent to a waste stream and not recycled. SORT-EE-01 is a screening test used early on in packaging design to obtain a preliminary evaluation of NIR sortation potential prior to performing more robust testing using SORT-S-01. Testing using SORT-S-01 is required to determine the Recyclability Category.

Test Protocols

SORT-EE-01 Early Evaluation of the Near Infrared (NIR) Sorting Potential of a Whole Plastic Article
SORT-S-01 Evaluation of the Near Infrared (NIR) Sorting Potential of a Whole Plastic Article

Resources

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

Recycling machinery, particularly automatic sorting equipment, 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.

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.

Test Protocols

SORT-S-02 Evaluation of the Size Sorting Potential for Articles with at Least 2 Dimensions Less than 2 Inches

Resources

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.

Requires Testing

Test Protocols

SORT-S-05 Evaluation of the Two Dimensional/Three Dimensional (2d3d) Sorting Potential of a Whole Article

Resources

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 - Material

PE blend of closure and base resin with melt index < 4.0 g/10 min per ASTM D1238 or calculated per RES-HDPE-01

PE blend of closure and base resin with melt index > 4.0 g/10 min per ASTM D1238 or calculated per RES-HDPE-01

Extrusion blow molding (bottles) and extrusion (pipe) are the two largest volume applications for recycled HDPE. Since polyethene closures and HDPE bottle resins combined in the HDPE recycling process, the melt flow index and density of the blend are required to be within the Preferred range for processability and mechanical performance required for the future use applications.

PP Polymer closure with total PP content < 10% of total package weight

PP can be a contaminant in HDPE and when mixed in an extruder the PP can reduce the impact properties and toughness of the recycled HDPE. An allowance of PP up to 10% of total package by weight reflects that the HDPE recycling stream routinely contains PP and reclaimers can manage and accept some PP content in the HDPE stream with minimal impacts

PP polymer closure with total PP content ≥ 10% of total package weight

When blended with PE, PP material exceeding more than 10% of total package by weight can negatively affects the impact properties and can render the material brittle.

Resources

RES-HDPE-01 Melt Flow Calc HDPE Blends Resource

Polyolefin Closure - Color

During the reclaiming process, closures are typically not separated from natural/unpigmented HDPE bottles. Since most closures are colored, the pigments from the closures mix with the natural-colored plastic of the bottle and cause a color shift known as Δ E . This color shift can limit the potential use of the rHDPE in future applications and should be avoided wherever possible.

Natural or white closures

During the reclaiming process, closures are typically not separated from natural/unpigmented HDPE bottles. To maximize the amount of higher valued natural rHDPE produced, it is best to use unpigmented or white closures wherever possible.

Colors with L value ≥ 40 where blend Δ E < 3.5
when tested using HDPE-S-01 or HPDE-CG-01 Path 1-B

Color with L value ≥ 40 where blend Δ E > 3.5
when tested using HDPE-S-01 or HDPE-CG-01 Path 1-B

For natural HDPE applications, there should be minimal changes in the color coordinates to prevent discoloration of the natural HDPE recycled content. Δ E values >3.5 become noticeable in color shift and are considered detrimental for use in natural HPDE applications.

Black or dark colored closures with L value < 40

Test Protocols

HDPE-S-01 Natural HDPE Flake Washing Test
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Non-Polyolefin Closure

Polymer density > 1.0 g/cm³ and sinks in water per O-S-01

Polymers with density greater than 1.0 g/cm³ are expected to sink in the float-sink tank, thereby separating and not impacting the recycled HDPE.

Contains any amount of PVC material

PVC is relatively easy to remove in the float-sink tank since it sinks while the HDPE floats. However, the float-sink tank is imperfect and even a very small amount of PVC with the recycled HDPE renders large amounts of it unusable as the PVC degrades at lower temperatures than those at which HDPE is processed.

Polymer density > 1.0 g/cm³ and floats in water due to foaming per O-S-01

Material with density >1.0 g/cm³ that floats in water (due to foaming) and passes through the float-sink tank along with the HDPE is difficult to remove with other methods and can cause contamination if not compatible with HDPE material. Testing using HDPE-CG-01 will verify the impact.

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Metal Lidding or 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 create wear in process machinery, increase operation costs and yield loss, and are a primary source of defects in products made with recycled HDPE.

Test Protocols

SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components

Resources

RES-SORT-03a Metal Sorting in the Plastics Recycling Process

Polyolefin Liner/Safety Seal

Made with EVA/TPE

EVA and TPE float in water and will not be separated in the recycling process. However, they are compatible with HDPE and in fact enhance its properties so they are preferred.

PP polymer closure liner/safety seal with total PP content < 10% of total package weight

An allowance of PP up to 10% of total package by weight reflects that the HDPE recycling stream routinely contains PP and reclaimers can manage and accept some PP content in the HDPE stream with minimal impacts.

PP polymer closure liner/safety seal with total PP content ≥ 10% of total package weight

When blended with PE, PP material exceeding more than 10% of total package by weight can negatively affects the impact properties and can render the material brittle.

Removable Closure/Liner/Safety Seal

APR Design Preferred

Regardless of material, designs that require complete removal by the consumer of the safety sleeve are Preferred, as the material will not be introduced into the recycling stream.

Non-Polyolefin Liner/Safety Seal

Polymer density > 1.0 g/cm³ and sinks in water per O-S-01

Polymers with density greater than 1.0 g/cm³ are expected to sink in the float-sink tank, thereby separating and not impacting the recycled HDPE.

Contains PVC material

PVC is relatively easy to remove in the float-sink tank since it sinks while the HDPE floats. However, the float-sink tank is imperfect and even a very small amount of PVC with the recycled HDPE renders large amounts of it unusable as the PVC degrades at lower temperatures than those at which HDPE is processed.

Polymer density > 1.0 g/cm³ and floats in water due to foaming per O-S-01

Material with density >1.0 g/cm³ that floats in water (due to foaming) and passes through the float-sink tank along with the HDPE is difficult to remove with other methods and can cause contamination if not compatible with HDPE material. Testing using HDPE-CG-01 will verify the impact.

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Liner/Safety Seal containing Aluminum or Paper

Detrimental to Recycling

These materials will contaminate wash water, will contribute to waste disposal costs, or will stick to the valuable HDPE and reduce quality and value of the final products.

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 - Material

Made with polyolefins and or polyolefin copolymers including TPO, EVA and TPE elastomers that float in water per O-S-01

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation

APR Recognized Solutions

Polyolefin Dispenser/Pump - Color

During the reclaiming process, spray dispensers and pumps are typically not separated from natural/unpigmented HDPE bottles. Since most are colored, the pigments from the spray dispensers and pumps mix with the natural-colored plastic of the bottle and cause a color shift known as Δ E . This color shift can limit the potential use of the rHDPE in future applications and should be avoided wherever possible

Natural or white

Colors with L value ≥ 40 where blend Δ E < 3.5
when tested using HDPE-S-01 or HPDE-CG-01 Path 1-B

Color with L value ≥ 40 where blend Δ E > 3.5
when tested using HDPE-S-01 or HDPE-CG-01 Path 1-B

For natural HDPE applications, there should be minimal changes in the color coordinates to prevent discoloration of the natural HDPE recycled content. Δ E values >3.5 become noticeable in color shift and are considered detrimental for use in natural HPDE applications.

Black or dark colored closures with L value < 40

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Test Protocols

HDPE-S-01 Natural HDPE Flake Washing Test
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Non-Polyolefin Dispenser/Pump

Made with a polymer of density > 1.0 g/cm³ and sinks in water per O-S-01

Polymers with density greater than 1.0 g/cm³ are expected to sink in the float-sink tank, thereby separating and not impacting the recycled HDPE.

Contains any amount of PVC material

PVC is relatively easy to remove in the float-sink tank since it sinks while the HDPE floats.However, the float-sink tank is imperfect and even a very small amount of PVC with the recycled HDPE renders large amounts of it unusable as the PVC degrades at lower temperatures than those at which HDPE is processed.

Made with a polymer of density > 1.0 g/cm³ and floats in water due to foaming per O-S-01

Material with density >1.0 g/cm³ that floats in water (due to foaming) and passes through the float-sink tank along with the HDPE is difficult to remove with other methods and can cause contamination if not compatible with HDPE material. Testing using HDPE-CG-01 will verify the impact.

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Contains Silicone

Sinks in water per O-S-01

Silicone that sinks in water can be separated out in the sink/float process and therefore not impact the recycled HDPE stream.

Floats in water per O-S-01

Silicone that floats passes through the float-sink tank along with the HDPE and is difficult to remove with other methods and can cause contamination if not compatible with HDPE material. Testing using HDPE-CG-01 can determine the impact.

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

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 create wear in process machinery, increase operation costs and yield loss, and are a primary source of defects in products made with recycled HDPE.

Test Protocols

SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components

Resources

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.

Workhorse Additive

Workhorse additives commonly used that have not been shown to cause significant issues with the recycling process or further uses of the recycled HDPE are: Thermal Stabilizers, UV Stabilizer, Nucleating Agents, Antistatic Agents, Lubricants, Fillers, Pigments, Impact Modifiers and Chemical Blowing Agents.

Workhorse Additive where PE blend density is ≤ 0.97 g/cm³

PE blend density is > 0.97 g/cm³

Some workhorse additives used with HDPE have higher densities and when incorporated into HDPE can increase the density causing it to sink in the float-sink tank. When a HDPE item sinks during reclamation, the item is lost as waste, reducing yield and increasing cost for the reclaimer. Density of HDPE blend with additives exceeding 0.97 g/cm³ should be tested using HDPE-CG-01 to determine impact.

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

EVOH

Ethylene Vinyl Alcohol copolymer (EVOH) is a common layer material used to increase the barrier properties of HDPE packaging. It is not separable in the recycling process and therefore will become part of the recycled HDPE. Maleated polyethylene (PE-g-MAH) tie layers are commonly used in combination with EVOH to improve the adhesion between HDPE and EVOH and have been shown to improve compatibility during the recycling process.

EVOH ≤ 6.0 wt% + PE-g-MAH tie layers with MAH > 0.1 wt% and EVOH:tie layers ratio ≤ 2

EVOH > 6.0 wt% + PE-g-MAH tie layers with MAH > 0.1 wt% and EVOH:tie layers ratio ≤ 2

EVOH > 1% with any other tie layer

Additives/Barriers with Density > 1.0 g/cm³

PE blend density is ≤ 0.97 g/cm³

PE blend density is ≥ 1.0 g/cm³ or
< 51 wt% of PE blend floats per O-S-01

Density is an important property and float-sink tanks are critical separation tools used by reclaimers. Many additives and barriers used with HDPE have higher densities and when incorporated into HDPE can increase the density causing it to sink in the float-sink tank. When a HDPE item sinks during reclamation, the item is lost as waste reducing yield, increasing cost, and thus will be categorized as non-recyclable.

PE blend density is > 0.97 g/cm³ and < 1.0 g/cm³

Many additives used with HDPE have higher densities and when incorporated into HDPE can increase the density causing it to sink in the float-sink tank. When a HDPE item sinks during reclamation, the item is lost as waste, reducing yield and increasing cost for the reclaimer. Density of HDPE blend with additives exceeding 0.97 g/cm³ should be tested using HDPE-CG-01 to determine impact.

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Optical Brightner

Detrimental to Recycling

Optical brighteners are not removed in the recycling process and can create an unacceptable fluorescence for next uses of recycled HDPE. 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.

Non HDPE Barrier/Coating

Requires Testing

Some Non HDPE layers and coatings have been found compatible with HDPE or are easily separated in conventional recycling systems. Testing must show that layers and coatings will either separate and be removed from the HDPE in the recycling process or have no adverse effects on the recycled HDPE in future uses. When used, their content should be minimized to the greatest extent possible.

Test Protocols

SORT-EE-01 Early Evaluation of the Near Infrared (NIR) Sorting Potential of a Whole Plastic Article
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Degradable Additives

Renders Package Non-Recyclable

See APR Position Paper on Degradable Additives.

Resources

APR-Position-Degradable-Additives

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 with labels within the Preferred surface coverage area are expected to sort accurately in both NIR and color optical sorters.

> 55% Surface Area Coverage

Labels with high surface area coverage may interfere with NIR detection of the HDPE article. SORT-S-01 determines if the HDPE article can be recognized and sorted properly to the HDPE stream. For more information on early evaluation testing for NIR sortation of packages see RES-SORT-01.

Test Protocols

SORT-S-01 Evaluation of the Near Infrared (NIR) Sorting Potential of a Whole Plastic Article

Resources

RES-SORT-01 Near Infrared (NIR) Sorting in the Plastics Recycling Process

Main Body Volume > 550 mL

≤ 75% Surface Area Coverage

Containers with labels within the Preferred surface coverage area are expected to sort accurately in both NIR and color optical sorters.

>75% Surface Area Coverage

Labels with high surface area coverage may interfere with NIR detection of the HDPE article. SORT-S-01 determines if the HDPE article can be recognized and sorted properly to the HDPE stream. For more information on early evaluation testing for NIR sortation of packages see RES-SORT-01.

Test Protocols

SORT-S-01 Evaluation of the Near Infrared (NIR) Sorting Potential of a Whole Plastic Article

Resources

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

Polymer film label that sinks in water

Polymers with density greater than 1.0 g/cm³ are expected to sink in the float-sink tank, thereby separating and not impacting the recycled HDPE

Polymer film label that contains PLA or PVC

PVC, when used with an adhesive that does not release in the wash, enters the extruder with the HDPE where they are incompatible. PVC degrades at HDPE extrusion temperatures and renders large amounts of the recycled HDPE unusable. When used with an adhesive that releases in the wash, these labels sink in the float-sink tank where they are removed. But because the float-sink tank is imperfect, and even a very small amount of PVC entering the extruder causes severe quality and yield problems, this material is detrimental.

Polyolefin film label that floats in water

Polyolefin labels are commonly expected to be PP films or PE film and are compatible with the natural HDPE recycling stream. However, given the natural HDPE stream is sensitive to discoloration through labels testing using HDPE-S-01 is required to determine the impact.

Non-Polyolefin label that floats in water

Non-polyolefin material that floats passes through the float-sink tank along with the HDPE and is difficult to remove with other methods and can cause contamination if not compatible with HDPE material. Testing using HDPE-CG-01 will verify the impact.

Test Protocols

HDPE-S-01 Natural HDPE Flake Washing Test
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

APR Recognized Solutions

Paper Label

Detrimental to Recycling

The HDPE reclamation process involves water and agitation. The paper that detaches from the container when subjected to these conditions becomes pulp, which does not sink intact but remains suspended in the liquid, adding load to the filtering and water treatment systems. Paper remaining adhered to the HDPE travels with the HDPE to the extruder where the material carbonizes and causes color defects. Even after melt filtering, the burned smell and discoloration remain with the recycled HDPE thereby negatively affecting its potential reuse.

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-3b 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.

Test Protocols

SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components

Resources

RES-SORT-03b Metal Decoration Resource

APR Recognized Solutions

The label inks, in conjunction with surface coverage area, substrate, metal decoration, and adhesives, must be considered when selecting a label.

Label Inks

Inks that do not discolor HDPE flake

Some label inks bleed color in the reclamation process, discoloring the HDPE in contact with them and possibly diminishing its value for recycling. If inks redeposit on natural HDPE flake, this discoloring may diminish its value for recycling.

Untested inks or inks that discolor HDPE flake

Test Protocols

HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

APR Recognized Solutions

Direct Print Inks

Inks that do not discolor HDPE flake

Inks used in direct printing may bleed or otherwise discolor the HDPE during the recycling process or introduce incompatible contaminants that reduce the value of the recycled HDPE. If inks redeposit on natural HDPE flake, this discoloring may diminish its value for recycling.

Untested inks or inks that discolor HDPE flake

Test Protocols

HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

APR Recognized Solutions

The label adhesive, in conjunction with surface coverage area, substrate, metal decoration, and inks, must be considered when selecting a label.

Releasing Adhesive

Used on Polymer Film Label Substrate that sinks in water

When used with a releasing adhesive, polymer labels that sink will detach from the HDPE container in wash and sink in the sink/float process where they can be removed from recycled HDPE stream.

Used on a non-polyolefin label that floats in water

Because HDPE flake floats, it is important to avoid using an incompatible polymer label that also floats when combined with HDPE. If such a label were to enter the extruder alongside the HDPE, it could lead to yield loss for the reclaimer due to the incompatibility between the polymers.

Used on polyolefin label substrate that floats in water

If the label is designed to separate from the HDPE container, it is desirable that the label floats so that the label might be recovered for recycle value. However, with natural HDPE the label can discolor the wash water and in turn the flake and must be tested using HDPE-CG-01.

Test Protocols

HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

APR Recognized Solutions

Non-Releasing Adhesive

Used on Non-Polyolefin Label Substrate

When used with an adhesive that does not release in the wash, Film labels with density greater than 1.0 g/cm³ enters the extruder with the HDPE where they are incompatible resulting in reclaimer yield loss.

Used on Polyolefin Label Substrate

A label that stays adhered the HDPE container should be a compatible polyolefin polymer, however, with natural HDPE the label can discolor the wash water and in turn the flake and must be tested using HDPE-CG-01.

Test Protocols

HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Plastic Attachments with Density > 1.0 g/cm³

Does Not Contain PVC materials

Contains PVC materials

PVC is relatively easy to remove in the float-sink tank since it sinks while the HDPE floats. However, the float-sink tank is imperfect and even a very small amount of PVC with the recycled HDPE renders large amounts of it unusable as the PVC degrades at lower temperatures than those at which HDPE is processed.

Paper Attachments

Detrimental to Recycling

The HDPE reclamation process involves a wash step that removes adhesives and other 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 HDPE and carbonize when the material is extruded, causing unacceptable quality degradation.

Polypropylene Attachments

PP Polymer attachment with total PP content < 10% of total package weight

PP can be a contaminant in HDPE and when mixed in an extruder the PP can reduce the impact properties and toughness of the recycled HDPE. An allowance for polypropylene up to 10% by weight of total package reflects that the HDPE recycling stream routinely contains PP and reclaimers can manage and accept some PP content in the HDPE stream with minimal impacts.

PP polymer attachment with total PP content ≥ 10% of total package weight

When blended with HDPE it negatively affects the impact properties and can render the material brittle. Attachments > 10% of total packaging by weight are shown to have a greater negative affect on recycled HDPE.

RFID Tags

Detrimental to Recycling

The use of RFID’s is discouraged as may limit HDPE yield, introduce potential contamination, and increase separation and waste disposal costs.

Metal Attachment

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 create wear in process machinery, increase operation costs and yield loss, and are a primary source of defects in products made with recycled HDPE.

Test Protocols

SORT-S-03 Evaluation of Sorting Potential for Plastic Articles Utilizing Metal, Metalized, or Metallic Printed Components

Resources

RES-SORT-03a Metal Sorting in the Plastics Recycling Process

Non-HDPE Attachments

Requires Testing

Testing using O-S-01 determines if the Non-HDPE attachment will sink in the float-sink tank, thereby separating and not impacting the recycled HDPE or if it will float with the HDPE and possibly contaminate the recycled HDPE. If the attachment floats along with the HDPE, testing using HDPE-CG-01 will determine the impact to the recycled HDPE stream.

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers

Welded Attachment

Requires Testing

Testing using O-S-01 determines if the Welded attachment will sink in the float-sink tank, thereby separating and not impacting the recycled HDPE or if it will float with the HDPE and possibly contaminate the recycled HDPE. If the attachment floats along with the HDPE, testing using HDPE-CG-01 will determine the impact to the recycled HDPE stream.

Test Protocols

O-S-01 Polyolefin Packaging Articles Sink or Float Evaluation
HDPE-CG-01 Critical Guidance Protocol for HDPE Rigid Containers