PET Bottles

Traditionally, unpigmented PET has the highest value and the widest variety of end-use applications. Transparent, green tinted bottles have the next highest value. Transparent light blue bottles are often included with green or clear streams successfully. PET bottles with other transparent tinted colors may have limited recycling value and may be considered contaminants by many PET reclaimers. Transparent colors other than green may be undesirable. There are some reclaimers, which are able to tolerate transparent, amber, tinted bottles in their systems.

The use of translucent and opaque colors is problematic for many recycled PET end uses because of contamination. In particular, TiO₂ is very detrimental to PET recycling for bottle-to-bottle and engineered resin uses. Although newer sorting technology is capable of identifying white PET from other PET colors, much current sortation capability does not always identify and isolate white opaque PET. Non-TiO₂ opaque and translucent PET bottles are also problematic and should be examined for their impact on the recycling process.

Inclusion of nucleating agents, hazing agents, fluorescers, and other additives for visual and technical effects should be examined specifically by the reclaiming industry for impact on the overall plastic bottle recycling stream. (APR strongly encourages bottle decision makers to test their opaque, translucent, and unusual transparent colors through its Champions for Change cooperative testing program to determine if the selections of color will act detrimentally on the reclaiming industry and if markets may be available for them.)

The use of PVC attachments of any kind on PET bottles is undesirable and should be scrupulously avoided. These attachments generally include, but are not limited to closures, closure liners, labels, sleeves, and safety seals. Very small amounts of PVC (in the parts-per-million range) can severely contaminate and render large amounts of PET useless for most recycling applications. In addition, PVC is very difficult to separate from PET in conventional water-based density separation systems, due to similar densities (densities greater than 1.0) that cause both to sink in these systems.

Plastic closures made from polypropylene are preferred to all others, as they are most easily separated from the bottle in conventional separation systems and create an ancillary stream of recyclable material. Closure systems that contain no liners and leave no residual rings, or other attachments, on the bottle after the closure is removed are also preferred. The use of PVC for closures or closure liners is undesirable and should be scrupulously avoided. While the use of EVA closure liners in plastic closures is acceptable to many reclaimers, EVA liners can cause contamination problems when used in aluminum closures. Although tolerated by many reclaimers, the use of aluminum closures should be avoided, as they are more difficult to separate from PET bottles compared to the preferred closure systems (PP, HDPE, LDPE) and add both capital and operating costs to conventional reclamation systems. Closures made from PS or thermoset plastics are undesirable and should be avoided.

If tamper resistance is required in specific product applications, it should be an integral design feature of the bottle. The use of tamper-resistant or tamper-evident sleeves or seals is discouraged as they can act as contaminants if they do not completely detach from the bottle, or are not easily removed in conventional separation systems. If sleeves or safety seals are used, they should be designed to completely detach from the bottle, leaving no remains on the bottle. The use of PVC sleeves or safety seals is undesirable and should be scrupulously avoided. Foil safety seals that leave foil or remnants or attaching adhesive on the PET bottle should be avoided.

PP, OPP, PE, or other label materials that float in water are preferred to all other label materials. Shrink labels with perforations to facilitate separation from bottles are the preferred label system. Label materials should not delaminate in the reclaimer's wash system. Paper labels are undesirable and should be avoided as they increase contamination in the PET due to fiber and adhesive carry-over through the reclamation process. Similarly, metallized labels increase contamination and separation costs and should be avoided. In general, the use of plastic labels with a specific gravity of less than 1.0 are preferred for easy removal in conventional water-based density separation systems. Label systems that sink in water because of the choices of substrate, inks, decoration, coatings, and top layer should be avoided. While PS labels are tolerated by many PET reclaimers, PS has been identified as causing serious processing and end-use problems by others, and should only be used if it can be easily and completely removed from the PET in conventional separation systems, such as expanded PS foam, where the PS density is much less than 1.0 gm/cm3 and can be easily separated from PET. The use of PVC labels is undesirable and should be scrupulously avoided. Full bottle sleeves should be so designed that automatic sorting equipment can properly identify the resin used to make the bottle.

Some label inks bleed color when agitated in hot water and can discolor PET regrind in the reclamation process, diminishing or eliminating its value for recycling. The APR and NAPCOR have developed a testing protocol to assist label manufacturers in evaluating whether a label ink will bleed in conventional PET reclaiming systems. Label inks must be chosen that do not bleed color when tested under this protocol. The use of label inks that bleed should be scrupulously avoided.

Pressure sensitive labels should separate from PET regrind in the hot caustic water wash step. Label adhesives should be water soluble or dispersible at temperatures between 140 °F to 180 °F in order to be removed in conventional washing and separation systems. If adhesives are not removed efficiently, they may disperse on the PET regrind and embed unwanted contaminants. The use of other adhesive types is discouraged and should be avoided. (The APR has developed a testing protocol for adhesive manufacturers to evaluate the impact of adhesive products in conventional PET reclamation systems). Adhesive usage and surface area covered should be minimized to the greatest extent possible to maximize PET yield and avoid contamination.

Presently, all direct printing other than date coding, either for product labeling or decoration, contaminates recycled PET in conventional reclamation systems and should be avoided. The inks used in direct printing may bleed ink or otherwise discolor the PET during processing, or introduce incompatible contaminants. In either case, the value of the PET for recycling is diminished or eliminated.

Some PET bottle designs require the use of barrier layers, coatings or additives to meet the requirements of specific product applications. Additives to PET bottles, including scavengers, which cause the PET to discolor and/or haze after remelting and solid stating, should be avoided unless means are readily and economically available to minimize the effects. Similarly, blends of PET and other resins are undesirable unless they are compatible with PET recycling.

In general, the use of non-PET layers and coatings are undesirable and should be avoided, unless they are compatible with PET or are easily separable from PET in conventional recycling systems. The use of EVOH, nylon-based (e.g., nylon-6, MXD6), epoxies, amorphous or "diamond-like" carbon, and silicon oxide barrier layers or coatings is currently tolerated by most reclaimers provided the layers/coatings readily separate and can be isolated or have been shown not to be a problem for the reclaiming process or reclaimed product. When used, their content should be minimized to the greatest extent possible to maximize PET yield, limit potential contamination, and reduce separation costs. The use of non-PET layers and coatings can drastically reduce the recyclability of PET bottles. (The APR's Champions for Change Cooperative Testing Program invites consumer product, plastic bottle and bottle component manufacturers to work with APR member companies to determine whether new modifications to a regularly recycled plastic bottle will impact conventional recycling systems prior to introducing the modification.)

The use of base cups is undesirable and should be avoided, as they reduce PET yield and increase separation costs. If base cups are used, the use of unfilled HDPE or clear PET is preferred to all other materials. If glued on, base cup adhesives should be water soluble or dispersible at 140 °F to 180 °F in order to be removed in conventional washing and separation systems. If adhesives are not removed efficiently, they may disperse on the PET regrind and embed unwanted contaminants. The use of other adhesive types is discouraged and should be avoided. (The APR has developed a testing protocol for adhesive manufacturers to evaluate the impact of adhesive products in conventional PET reclamation systems). Adhesive usage and surface area covered should be minimized to the greatest extent possible to maximize PET yield and avoid contamination.

The use of any other attachments is discouraged, as they reduce base resin yield and increase separation costs. If any other attachments to a bottle are used, they should be made from HDPE or clear PET. The use of welded attachments should be avoided. The use of non-PET attachments, such as handles, should not be adhesively bonded to the bottle and should readily separate from the bottle in conventional PET reclamation systems. If adhesives are used to affix attachments, they should be water soluble or dispersible at 140 oF to 180 oF in order to be removed in conventional washing and separation systems. If adhesives are not removed efficiently, they may disperse on the PET regrind and embed unwanted contaminants. The use of other adhesive types is discouraged and should be avoided. (The APR has developed a testing protocol for adhesive manufacturers to evaluate the impact of adhesive products in conventional PET reclamation systems). Adhesive usage and surface area covered should be minimized to the greatest extent possible to maximize PET yield and avoid contamination.

The use of RFIDs (radio frequency identification devices) on bottles, labels or closures is discouraged and should be avoided unless they are compatible with PET recycling and are demonstrated not to create any disposal issues based on their material content. The use of RFIDs is discouraged as it limits PET yield, introduces potential contamination, and increases separation costs.

The use of non-detaching bottle components, including monomers, that are not made from PET, must be either compatible with, or easily separable from PET in conventional recycling systems, and must not adversely affect end-use product performance.

The use of postconsumer PET in bottles is encouraged, whenever possible.