Polymers with density < 1.0 that float in water (specifically PE & PP closures; PE foam, EVA, TPE liners)
The density of PET is 1.38 and so it sinks in water. Since these other polymers float in water, they are most easily separated from PET flake in conventional separation systems. Additionally, the PET recycling process captures floatable PE and PP closures to create an ancillary stream of marketable material. Care must be taken when modifying the PE or PP, with mineral fillers for example, to ensure the modifier does not increase the overall density to the point it sinks.
The use of PVC in spray dispensers or pumps renders 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 intolerant of even minute amounts of PVC.
REQUIRES TEST RESULTS
Valves containing silicone (density and floatability will vary)
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. It should float in the sink/float system or be compatible with PET if it sinks. Companies that are considering such components and are unsure of their compatibility with recycling should ask their suppliers to provide APR test results.
Valves or springs made of metal
Metal contamination is highly undesirable in recycled PET. Metals create wear in process machinery, increase operation costs and yield loss, and are a primary source of defects in products made with recycled PET. MRFs and PET reclaimers use magnets, eddy current separators and metal detectors to keep packages with metal components out of the process stream. Metal components such as pump springs or valves that trigger metal detectors will cause the entire plastic item to be removed from the stream and not recycled. Any dispenser containing metal components must be tested to determine the recyclability category. At best, sortation testing will classify such an item as Detrimental to Recycling.