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1,000 ppm Irgaphos 168, the OIT value will be around 70 min- blends and only buy high quality reprocessed recycled material
utes and the pipe will be well stabilized. from the recycled suppliers. Because of this complicated way in
which recycled resin may make its way into AASHTO approved
pipe, there could be up to five different specifications.
Specifications
First, one may need a specification for post-consumer recy-
Ensuring consistent properties for blends containing recycled cled, mixed-color reprocessed (PCR-MCR) HDPE in pellet
resins will be challenging. There are a number of different form. This will be used by compounders and corrugators to
kinds of companies that will be involved once AASHTO allows ensure that they are receiving a consistent stream of material
recycled use. from which to make recycled blends. Its focus will be mostly
At the beginning of the process are the recycled-resin on how well the material is melt filtered and how much
suppliers. These companies specialize in locating, cleaning, polypropylene is present, among other things. These are
reprocessing, and selling recycled materials. Some are small believed to be important properties for good recycled material.
family-owned businesses that simply grind and clean recycled Then there may be two specifications for fully formulated
materials while others are fairly sophisticated with auto- recycled contentcontaining blends. One will be for use in pipe
mated cleaning and optical color sorting. And there are many for AASHTO M252 and drainage applications and the other
in-between. Some will be happy just selling reprocessed re- for M294 applications. Apparently, these two applications are
cycled HDPE and others will want to prepare and sell fully different enough that a different quality and type of resin is
formulated blends directly to the corrugated pipe manufac- used for each one. These are necessary for the corrugators to
turer. Next will be the compounders. This group may include know what is being purchased to be converted to pipe.
the recycled-resin supplier, but other companies with estab- Finally, there will also be two specifications--M252-Recycled
lished sources of sub-prime virgin resins will use their blending and M294-Recycled--for pipe made from recycled content
and formulating technology to make fully formulated recycled containing resins. These specifications will include both resin
blends for direct sales to the corrugators. And, finally, some properties and the properties of the final pipe; all testing will
pipe manufacturers themselves may want to prepare their own be conducted on the pipe or on samples taken from the pipe.
