Pigmented HDPE

In general, copolymer HDPE bottles are pigmented. However, there are some product applications that use unpigmented copolymer HDPE bottles. This presents a challenge for some plastic reclaimers that use pigmentation as the basis by which they distinguish and sort copolymer HDPE from homopolymer HDPE bottles. In multi-layer HDPE bottle designs, the use of inner layers of the same color as the surface layer is preferred to maximize recyclability. However, inner layers of different color than the surface layer are tolerated in many conventional reclamation systems.

Plastic closures made from HDPE, LDPE, or PP are preferred to all others. Also preferred, are closure systems that contain no liners and leave no residual rings, or other attachments, on the bottle after the closure is removed. The use of closures that are the same color as the bottle is desirable. The use of PVC for closures or closure liners is undesirable and should be avoided. The use of metal closures is undesirable and should be avoided as they are more difficult and more costly to remove in conventional HDPE reclamation systems compared to the preferred closure systems (HDPE, LDPE, or PP). The sum of PP and LDPE closure and attachments should be limited to less than 5% of the total bottle weight.

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. Shrink sleeves are preferred to adhered labels. Shrink sleeves made from PE or PP are preferred. The use of PVC sleeves or safety seals is undesirable and should be avoided. Foil safety seals that leave foil or remnants or attaching adhesive on the HDPE bottle should be avoided.

PP, OPP, HDPE, MDPE, LDPE, LLDPE, and PS label stock are preferred to all other label materials. The preferred label systems are shrink sleeve labels that require no adhesive. Paper labels are undesirable and should be avoided as they can increase contamination in the HDPE due to fiber and adhesive carry-over through the reclamation process. Similarly, metallized labels increase contamination and separation costs and should be avoided. The use of PVC labels is undesirable and should be avoided. Full bottle sleeves should be so designed that automatic sorting equipment can properly identify the resin used to make the bottle.

Inks must be chosen that do not bleed color when agitated in water. Label inks that bleed and can discolor the HDPE regrind in the reclamation process, diminishing or eliminating its value for recycling. The use of label inks that bleed should be scrupulously avoided. (The APR has developed a testing protocol to assist label manufacturers in evaluating whether a label ink will bleed in conventional HDPE reclamation systems).

The use of “hot melt” adhesives is undesirable and should be avoided unless the adhesive readily separates from the plastic and does not cause problems in the reclaiming process. 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 HDPE 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 HDPE reclamation systems). Adhesive usage and surface area covered should be minimized to the greatest extent possible to maximize HDPE yield and avoid contamination.

Direct printing other than date coding, either for product labeling or decoration, can contaminate recycled HDPE copolymer in conventional reclamation systems. The inks used in direct printing may bleed ink or otherwise discolor the HDPE during processing, or introduce incompatible contaminants. In either case, the value of the HDPE for recycling is diminished or eliminated. Testing should be conducted to confirm no adverse impact on the reclaiming process or product.

Some pigmented, HDPE bottle designs require the use of layers for specific product applications. In multi-layer HDPE bottle designs, the use of inner layers of the same color as the surface layer is preferred to maximize recyclability. However, inner layers of different color than the surface layer are tolerated in many conventional reclamation systems. The use of non-HDPE layers is undesirable and should be avoided, unless they are compatible with or easily separable from HDPE in conventional recycling systems. Current HDPE recycling systems can tolerate the use of EVOH layers, provided the total EVOH concentration is minimized to the greatest extent possible. Similarly, MXD6 and other nylon-based layers are tolerated, particularly if the layers readily separate from the HDPE in conventional reclamation systems. If layers must be used, their content should be minimized to the greatest extent possible to maximize HDPE yield and reduce potential contamination and separation costs. (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 additives such as calcium carbonate, talc, or other fillers in concentrations that alter the density to greater than that of water (causing the HDPE plastic sinks in water), or alter properties of the HDPE regrind are undesirable and should be avoided.

Other attachments made from HDPE are preferred to all others as the use of non-HDPE attachments reduce base resin yield and increase separation costs. Other attachment may include handles, inserts and pour spouts, in addition to others that might be developed. Non-HDPE attachments should not be adhesively bonded to the bottle and must readily separate from the bottle in conventional HDPE reclamation systems. If non-HDPE attachments are added to a bottle, they should be made from materials with a density greater than 1.0 that will easily separate from HDPE in conventional separation systems with the exception of PVC, which is undesirable and should be avoided. The use of PP or LDPE attachments, if necessary, and closures should be limited to less than 5% of the total bottle weight. Higher percentages can contaminate the HDPE for many recycling applications, as these materials are difficult to separate from HDPE in conventional systems. If pour spouts are added to a bottle, they should be designed to leave no product residue and allow for complete removal of product contents when the bottle is emptied. The uses of attachments that contain metallic components are discouraged and should be avoided. If adhesives are used to affix attachments, they 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 HDPE 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 HDPE reclamation systems). Adhesive usage and surface area covered should be minimized to the greatest extent possible to maximize HDPE yield and avoid contamination.

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