The Association of Plastic Recyclers
  • PS/EPS

    PS/EPS

Polystyrene (PS)

PREFERRED

Clear PS attachments

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.

DETRIMENTAL

Paper attachments

The PS reclamation process uses a wash to remove glue and other contaminants to the levels required to render the RPS 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 final polymer. Paper fibers remaining in the RPS carbonize when the material is reused causing quality degradation.

Welded attachments

A certain amount of a welded attachment cannot be separated from the main polymer in the recycling process. These attachments, even when ground and made of floatable materials, cause contamination and yield loss issues in both cases: when the PS 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

Unless they are compatible with PS 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 yield, introduces potential contamination, and increases separation costs.

Also see "Requires Test Results" Section

RENDERS NON-RECYCLABLE

PVC and PLA attachments

The use of PVC or PLA attachments of any kind on PS packaging is undesirable and should be scrupulously avoided. This includes thermoforms of PVC that may be visually confused with rigid PS thermoforms. Very small amounts of PVC or PLA can severely contaminate and render large amounts of PS useless for most recycling applications. In addition, PVC and PLA are very difficult to separate from PS in conventional water-based density separation systems due to similar densities (densities greater than 1.0) that cause both to sink in these systems.

REQUIRES TEST RESULTS

Metal, metalized and metal containing attachments

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.

Examples include metal foils and metalized substrates that sink in water. In the recycling process these items are either identified and removed along with their PS 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 PS in the float-sink tank.

If a metalized attachment causes the PS bottle to fail sortation testing, the bottle is Rendered Non-Recyclable as it is removed from the stream and discarded. If a metalized attachment passes through sortation, it is considered Detrimental as it contaminates PS.

BENCHMARK TEST

Non-PS attachments such as handles

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.

No test methods currently exist for PS. However, PET Package Component Sink/Float Evaluation (PET-S-05) may be adapted substituting PS for PET.

SCREENING TEST


Expanded Polystyrene (EPS)

PREFERRED

Clear PS attachments

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.

DETRIMENTAL

Paper attachments

The EPS reclamation process uses a wash to remove glue and other contaminants to the levels required to render the rEPS 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 final polymer. Paper fibers remaining in the rEPS carbonize when the material is reused causing quality degradation.

Welded attachments

A certain amount of a welded attachment cannot be separated from the main polymer in the recycling process. These attachments, whether made of floatable or sinking materials, cause contamination and yield loss issues when the EPS they are attached to causes the ground section containing both polymers to float.

RFID’s (radio frequency identification devices) on packages, labels or closures

Unless they are compatible with EPS 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 yield, introduces potential contamination, and increases separation costs.

RENDERS NON-RECYCLABLE

PVC attachments

The use of PVC attachments of any kind on EPS packaging is undesirable and should be scrupulously avoided. Float sink tanks are not perfect machines. Even though PVC sinks and the EPS floats small amounts of PVC travel with the EPS. Very small amounts of PVC or PLA can severely contaminate and render large amounts of PS useless for most recycling applications.

REQUIRES TEST RESULTS

Non-PS attachments such as handles

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 sink in water such as filled PP/HDPE, or PET. If adhesives are used to affix attachments, their selection should consider the adhesive criteria within this document.

Screening Test: TBD

Metal, metalized and metal containing attachments

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 EPS. Metals create wear in process machinery, increase operation costs and yield loss, and are a primary source of defects in products made with recycled EPS. MRFs and EPS reclaimers use magnets and metal detectors to keep packages with metal components out of the process stream. Metal components such as closures or lidding that trigger metal detectors will cause the entire plastic item to be removed from the stream and not recycled. At best, sortation testing will classify such an item as Detrimental to Recycling.

BENCHMARK TEST

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