Page 30 - Plastics News November 2021

FEATURE

What Goes In Making PCR A Viable Option?

Anna Rajkovic, & Tammy Rucker

Understanding how to work with the PCR available today is critical as packaging and other products
are being redesigned for circularity.

landfilled; and to fully close the loop, the
materials in them must be incorporated
back into new products. PCR is the
primary focus for most participants in the
value chain, and reincorporating it into
new products and packaging is critical
to circularity.

What Properties and Processibil-
ity Should You Expect from PCR
Resins?
Melt index (MI), melt-flow ratio
(MFR) and density are basic properties
that should be communicated on every
lot of PCR. Since PCR is often used as
liminating plastic waste in the repelletized to be used in new plastic a blend component, these properties will
Eenvironment is critical to the health articles or packaging. Post-industrial affect blend compatibility, which will
of our planet and the health of our (PIR) resin, on the other hand, is typically affect overall performance.
industry. Circularity is being advanced resin that has been converted into a
with downgauging and lightweighting, product that is out of specification or For PE-PCR, sophisticated rheology
and processors are working with brand not saleable, and thus has never reached curves are more commonly used
owners to redesign packaging for the customer or consumer. This product with virgin resin, but understanding
recyclability and to incorporate post- can still be collected and diverted from whether LDPE is present in a LLDPE
consumer resin (PCR) and other recycled landfill and used in new products or PCR is important to predict the shear-
content. packaging. thinning behavior and melt strength
during processing. While it is difficult to
As you embark on this endeavor, learn Rework is waste generated within a quantify the level of LDPE in a specific
as much as you can about the PCR that manufacturing process that is reused batch of LLDPE PCR, understanding
is available today. Understanding what within the same process rather than sold whether it is present in the incoming
to expect when working with recycled to another manufacturer. The ability to recovered plastic stream is a good
resin is critical as we continue to drive use rework as a feedstock is considered a start. The processability of PCR can be
improvements of both the quality and best practice in manufacturing. This resin affected by contaminants, especially if
quantity of recycled plastics. It will give is very close to virgin resin in quality since they do not melt at temperatures used
you more confidence and improve your it has only experienced one additional for PE extrusion. PET is a good example,
success in incorporating this sustainable heat or processing history. Examples as its higher melt temperature will result
material into new packaging and products. include tips and tails from blow molding, in blockage of the extruder screen pack,
Here are eight questions whose answers runners from injection molding, and building up backpressure and potentially
will help put you on the right track. edge trim from film or sheet production. causing downtime. Foreign contaminants
Rework is considered distinct from PCR
How is PCR Different from PIR and PIR, as it is reused back in the same such as cellulose or wood fibers can also
and Rework? process that created it. As such, it is not result in screen-pack buildup. A good
PCR is defined as plastic that has considered a recycled product.Products rule of thumb is that your PCR supplier
served its defined purpose. After its must be designed to be recycled or should be using mesh filtration one step
intended use, it is collected, cleaned and upcycled rather than downcycled or finer than that which is used on your

30 PLASTICS NEWS NOVEMBER 2021