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The
basic design for recyclability guideline to consider when
making material choices for any attachment to a bottle is
to consider its general compatibility with the base resin
(copolymer HDPE) or the removal efficiency in conventional
water-based separation systems that separate plastics by density.
These attachments may include closures, closure liners, base
cups, inserts, labels, pour spouts, handles, sleeves, safety
seals, coatings and layers. HDPE has a density less than 1.0
and will float in these systems. For efficient separation
and removal in conventional sink/float separation systems,
attachments should be made from materials with a density greater
than 1.0 or be otherwise compatible with HDPE in the reclamation
process. Materials with a density greater than 1.0 will sink
in these systems and can be easily separated from the HDPE.
(Density
range of key plastic materials.)
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 metal closures is undesirable and should be avoided as they
are more difficult and more costly to remove in conventional
reclamation systems compared to preferred closure systems (HDPE,
LDPE or PP).
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. Shrink sleeves are preferred when sleeves are
necessary. The use of PVC sleeves or safety seals is undesirable
and should be avoided.
In general, copolymer HDPE bottles are pigmented. However, there
are some product applications that use unpigmented copolymer
HDPE bottles. This concerns some plastic reclaimers that use
pigmentation as the basis for distinguishing and separating
copolymer HDPE from homopolymer HDPE bottles.
PP, OPP, HDPE, MDPE, LDPE, LLDPE or PS label stock is preferred
to all other label materials. 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.
Inks must be chosen that do not bleed color when agitated in
water as they can discolor the HDPE regrind during the reclamation
process, diminishing or eliminating its value for recycling.
The use of 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.) Label adhesives should be water-soluble
or dispersible at temperatures between 140°F and 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 reclamation systems.) Adhesive usage and surface
area covered should be minimized to the greatest extent possible
to maximize HDPE yield and avoid contamination.
Some pigmented HDPE bottle designs require the use of layers
for specific product applications. 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 both EVOH and MXD6 layers. 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 manufacturers and 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 other attachments is discouraged, as they reduce
base resin yield and increase separation costs. Other attachments
may include handles, inserts and pour spouts, in addition to
others that might be developed. If attachments are added to
a bottle, they should be made from 1) materials with a density
greater than 1.0 that will easily separate from HDPE in conventional
separation systems, or 2) compatible materials such as PP, LDPE
or preferably, unpigmented, homopolymer HDPE. The use of PP
or LDPE attachments, if necessary, should be limited to less
than 5 percent 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 empty. If adhesives
are used to affix attachments, they should be water-soluble
or dispersible at temperatures between 140°F and 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 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 post-consumer HDPE in bottles is encouraged, whenever
possible. |
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