The Association of Plastic Recyclers
  • HDPE

    HDPE

PREFERRED

Natural or White Colored Closures on Natural HDPE Bottles

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. This color shift can limit the potential use of the rHDPE in future applications. To maximize the amount of higher valued natural rHDPE produced, it is best to avoid pigmented closures wherever possible.

Colored closures on Natural HDPE bottles where L value > 40 and Δ E of blend < 3.5

For natural HDPE applications, there should be minimal changes in the color coordinates. The color shift or Δ E can be determined by testing per APR-HDPE-S-01 or Path 1-B per APR-HDPE-CG-01

Primary Material employed to make closure shell, fitment or spout

  • HDPE, LLDPE, and LDPE closures when the Melt Flow Index of a blend of the closures and base resin employed for the container is < 4.00 g/10 min.

    Melt Flow Index can be determined using ASTM D1238.

    Calculations can be employed as an alternative to laboratory testing to determine what Melt Flow Rate of a blend of two different polyethylene resin is. See APR-RES-MFR-01 for calculations.

  • Polypropylene closures that are < 10% of the package weight

    Polypropylene can be a contaminant in HDPE. When HDPE and PP are melt mixed in an extruder the PP exists as a second phase which can dramatically reduce the impact toughness that is a valuable property of recycled HDPE.

    To evaluate the 10% limit, APR guidance is to employ as numerator the sum all the PP employed on a closure, fitment, pour spout, or over-cap employed on a package. Then the denominator is the sum of the PP just mentioned along with the weight of the HDPE used to make the package. Any PP from labels or attachments is ignored in this evaluation.

    An allowance for up to 10 wt% polypropylene from closures reflects that the HDPE recycling stream routinely contains PP and reclaimers can manage and accept some PP content in the HDPE stream.

  • Closures made of polymers with density > 1.0 g/cm3 that sink in water per APR-O-S-01 and do not contain PVC

    Polymers with density greater than 1.0 g/cm3 are expected to sink in the float-sink tank, thereby separating from the HDPE. They also do not damage or wear cutting machinery in the recycling process. Small amounts of these materials that make it through the float-sink process can be melt filtered from the recycled HDPE in the extrusion step. However, these materials are lost to the waste stream in the recycling process and are considered less preferable than an alternative floating attachment that is compatible with HDPE.

Click below for commercially available Closures that have achieved APR Design for Recyclability Recognition

APR Design® for Recyclability Recognitions

Liners and safety seals on closures
  • Any floating olefin-based polymer, or polymer compound, may be employed to make a liner or safety seal on a closure. The following materials are within the scope of floating olefin-based polymers:

    • The finished polymer compound, with any additives and color concentrate, has a density less than 0.985 g/cm3, or can be shown to float in water using APR O-S-01.
    • Polypropylene, including copolymers with ethylene, impact modified grades, nucleated or clarified grades. Polypropylene in the very small amounts from liners or safety seals have a very minimal negative impact on the HDPE flake. Such attachments that remain with the HDPE throughout the recycling process increase yield and have minimal negative quality impact for the reclaimer.
    • Ethylene polymers and copolymers, including EVA copolymers and ionomers.
    • Thermoplastic elastomers based on olefinic constituents. The more common elastomers are ethylene and/or propylene based plastomers/elastomers, as well as olefin block copolymers, including SEBS.
    • Foamed olefin-based materials
  • Liners or safety seals/sleeves made of polymers with density >1.0g/cm3 that sink in water per APR-O-S-01 and do not contain PVC

    Polymers with density greater than 1.0 g/cm3 are expected to sink in the float-sink tank, thereby separating from the HDPE. They also do not damage or wear cutting machinery in the recycling process. Small amounts of these materials that make it through the float-sink process can be melt filtered from the recycled HDPE in the extrusion step. However, these materials are lost to the waste stream in the recycling process and are considered less preferable than an alternative floating attachment that is compatible with HDPE.

  • Liners or Safety seals/sleeves that are designed to be completely removed before the package can be opened

    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.

DETRIMENTAL

Colored closures on Natural HDPE bottles where L value > 40 and Δ E of blend > 3.5

The color shift or Δ E can be determined by testing per APR-HDPE-S-01 or Path 1-B per APR-HDPE-CG-01

Δ E values >3.5 become noticeable in color shift for natural HDPE and are considered detrimental for use in natural (uncolored/non-tinted) applications.

Polypropylene closures that are ≥ 10% of the package weight

APR recognizes that polypropylene is perhaps the most commonly used material for closures.

HDPE packages with PP closures are considered recyclable (as long as all other components are Preferred), but with a Detrimental feature if the weight of the closure relative to the total weight of the package is greater than 10%.

Since polypropylene floats in water like polyethylene it is not separated in the reclaimers float-sink tank. When blended in higher amounts, HDPE it negatively affects the impact properties and can render the material brittle.

Closure liners or Safety Seals that are composites of Aluminum and Paper

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.

Closures, Closure Liners and Safety Seals that sink in water per APR-O-S-01 and contain 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.

RENDERS NON-RECYCLABLE

Black or dark colored closures with L value < 40 on natural HDPE bottles

REQUIRES TEST RESULTS

Closures, Liners and Safety Seals made of polymers with density > 1.0 g/cm3 that float water per APR-O-S-01

This material 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.

SCREENING TEST

DEFINITIVE TEST

Dispensers, closures or lidding with metal components

Sortation testing for metal components will result in either a Detrimental or a Renders Non-Recyclable ruling. Metal components cannot be Preferred at this time.

Metal contamination is highly undesirable in recycled HDPE. 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. MRFs and HDPE reclaimers use magnets, eddy current separators and metal detectors to keep packages with metal components out of the process stream. Any metal components, such as pump springs, valves, safety sleeves, or lidding that trigger the metal detector will cause the entire plastic item to be removed from the stream and not recycled.

Although metal is easily removed in the float-sink process, most reclaimers have metal detection equipment designed to protect their cutting machinery. Therefore, the container never makes it to the float-sink tank. Large metal items attached to HDPE packages may cause the package to be directed to the metal or waste stream in the recycling process, causing yield loss.

BENCHMARK TEST

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