The Association of Plastic Recyclers
  • PET

    PET

Label selection should be considered carefully to find the solution most compatible with the recycling process that also provides the necessary performance characteristics. At a minimum, labels must be designed so NIR sorting machinery can identify the bottle polymer with the label attached, and labels should use adhesives that release from the bottle. Removing adhesives is a significant component to the cost of recycling so the packages using the lowest quantity of appropriate adhesive are the most compatible.

APR provides an overview of labels and their compatibility with specific portions of the recycling process in our Label Summary Table. All labels should meet guidance for coverage and compatibility, and tested in any areas where this is unclear. 

Additional guidance for choosing labels can be found in the following Resource Documents:

PREFERRED

Polymer labels with a density < 1.0 that float in water, specifically polypropylene or polyethylene

The density of PET is 1.38 and so it sinks in water. These other materials float in water so they are separated from the PET in the float-sink tank with the closures. Since they are the same general polymer as most of the closures they do not contaminate or devalue this stream. Care should be taken to ensure that any modifiers to the label material do not increase its density above 1.0.

Full bottle sleeve labels that have received APR Critical Guidance Recognition

Several companies have received APR Critical Guidance Recognition for full bottle sleeve labels for PET bottles. In order for any of these materials to be considered Preferred Design, the specific items must have been tested and found Preferred based on the test results. Significant data is available to determine whether a full bottle sleeve label may be compatible with PET recycling, and APR offers test methods to verify this.

Labels that do not fully cover the sidewall of a bottle

For Near Infrared (NIR) sorting of container resin, testing has shown that a high-coverage label may cause a false reading on an NIR automatic sorter and direct a PET bottle to another material stream where it is lost to the process. There is no specific guidance on label surface coverage for NIR sortation at this time (see Requires Testing below). 

For correct color sortation at the reclaimer, testing has shown that high surface coverage labels can impede sortation of clear bottles into the clear stream. An automated color sorter must be able to detect a clear PET bottle beneath a printed label and properly sort it into the clear, rather than color, PET bottle stream.

Preferred label coverage guidance for color sortation:

  • For containers of 550 ml or less, cover not more than 55% of the bottle surface area with label
  • For containers greater than 550 ml, cover not more than 70% of the bottle surface area with label

Label percent surface area coverage is based on the label surface area divided by the surface area of the bottle, not including the neck finish or bottle base surface area.

Labeled bottles that are outside of the guidance above can be evaluated via the APR Evaluation of Color Sorting Potential of Labeled Articles (NOTE: test document under development)

DETRIMENTAL

Paper labels

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.

Polymers with density > 1.0 except PVC and PLA

The density of PET is 1.38 and so it sinks in water. The reclaimers rely on float-sink systems to separate non-PET materials. Label components that sink with the PET end up in the RPET stream as contaminants. PVC and PLA are unacceptable at any level.

RENDERS NON-RECYCLABLE

PVC and PLA

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.

REQUIRES TEST RESULTS

Laminated label substrate

Labels that break into small, very thin pieces of material are more difficult to manage in the recycling process because they behave erratically in a float-sink tank. Therefore, labels that stay intact are preferred. Carry-over of delaminated labels into the RPET can result in contamination.

In order for any of these label materials to be considered Preferred Design, the specific items must have been tested and found Preferred based on the test results. If these items have not been tested, they are considered Detrimental to Recycling. Testing will determine the appropriate category.

Companies that are considering such materials and are unsure of their compatibility with recycling should ask their suppliers to provide APR test results.

DEFINITIVE TEST

Full bottle sleeve labels

Much is known about the sortability and recycling compatibility of full bottle sleeve labels, as explained in APR’s Resource Document. Several label technologies have received Critical Guidance Recognition. For innovative or new designs for full body sleeve labels, testing will determine the appropriate category.

Full bottle sleeve labels must be tested for both bottle surface area coverage and compatibility with PET.

Surface area

Some sleeve labels cover a large amount of the bottle surface with a polymer that is not the same as the bottle body. The label may then cause a false reading on a Near Infrared (NIR) automatic sorter and direct a PET bottle to another material stream where it is lost to the process. High surface coverage labels can also impede detection of the color of a PET bottle. Automated color sorters must be able to detect a clear PET bottle beneath a printed label and properly sort it into the clear, rather than color, PET bottle stream. If a bottle is lost in either the NIR or the color the sortation process, it is rendered non-recyclable as it does not enter the stream and is discarded as waste.

Testing has shown that best practice guidance recommends:

  • For containers of 550 ml or less, cover not more than 55% of the bottle surface area with label
  • For containers greater than 550 ml, cover not more than 70% of the bottle surface area with label

If one’s design is outside of the best practice guidance above, the labeled bottle must be evaluated using the NIR sortation potential test and the forthcoming APR Evaluation of Color Sorting Potential of Labeled Articles.

DEFINITIVE TEST

Compatibility

Some sleeve label materials have a density of > 1.0, and thus sink in the float/sink tank and remain with the PET. This material cannot be removed in the recycling process and can contaminate the RPET produced if not compatible with PET.

SCREENING TEST

DEFINITIVE TEST

Metal foil, metalized and metallic printed labels

Sorting equipment in the recycling process is designed to detect and eliminate metal from PET. Even very thin metallized labels may be identified as metal by the sorting equipment and cause the entire bottle to be rejected as waste, thereby creating yield loss. If not detected, metals pass through the process with the PET and cause contamination issues in the RPET.

If a bottle is lost in the metal sortation process, it is rendered non-recyclable as it does not enter the stream and is discarded as waste. If a bottle passes through sortation, it is categorized as Detrimental due to the contamination of PET that results from metal residue.

BENCHMARK TEST

Polystyrene labels

The density of PET is 1.38 and so it sinks in water. Polystyrene has a density of > 1.0, 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. However, expanded PS may float and be separable from the PET.

SCREENING TEST

Label structures that sink in water because of the choice of substrate, ink, decoration, coatings, and top layer

The density of PET is 1.38 and so it sinks in water. The reclaimers rely on float-sink systems to separate non-PET materials. Label components that sink with the PET end up in the RPET stream as contaminants.

SCREENING TEST

DEFINITIVE TEST

PET Preferred Guidance

Closure

Closure

Made of PE or PP so it separates from PET in a float/sink tank and can be sold as a side stream by reclaimer.
Dimensions

Dimensions

More 2D (round) than 3D (flat), and larger than 5 cm in two dimensions.
Layers & Coatings

Layers & Coatings

APR Critical Guidance recognized barriers or protective coatings.
Resin

Resin

PET with a crystalline melting point between 225C and 255C. Post consumer PET (RPET) content is encouraged.
Label

Label

Crystallizable PET or a polymer that floats in water; label covers less than 100% of bottle surface.
  • Closure

    Closure

    Made of PE or PP so it separates from PET in a float/sink tank and can be sold as a side stream by reclaimer.
  • Dimensions

    Dimensions

    More 2D (round) than 3D (flat), and larger than 5 cm in two dimensions.
  • Layers & Coatings

    Layers & Coatings

    APR Critical Guidance recognized barriers or protective coatings.
  • Resin

    Resin

    PET with a crystalline melting point between 225C and 255C. Post consumer PET (RPET) content is encouraged.
  • Label

    Label

    Crystallizable PET or a polymer that floats in water; label covers less than 100% of bottle surface.

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