BEST PRACTICES IN PET INTERMEDIATE PROCESSING
Dirty Regrind Specifications
Issue: The quality requirements for PET regrind are far more demanding than for baled PET. And, the allowable levels of contamination in PET regrind are in the parts per million range. The quality of PET regrind is crucial to the efficiency and economics of subsequent PET recycling processing stages. Producing dirty regrind that meets the following specifications will ensure the ability to market granulated PET.
Best Practice: The proposed best practice post-consumer PET “dirty” regrind specifications that follow are not intended to meet any one company’s individual specifications, but to represent a standard that will be acceptable to most PET purchasers and ensure a quality standard that can reduce the cost of the PET recycling process. While the proposed specifications may represent a standard which is acceptable to most of the PET recycling industry, every PET processor has specific requirements based on their particular processing system and the end-use application for which the recycled PET is intended. Therefore, suppliers must always determine the exact levels of contamination that a particular purchaser accepts as well as any other unique purchasing specifications they might have.
Unlike baled PET bottles, specifications for PET regrind vary by color and by the end-use application for which they are intended. As a general rule of thumb, higher value end-use applications demand higher quality regrind, particularly in regard to PVC contamination.
The following PET regrind specifications are broken down into four end-use categories as follows: Packaging, Sheet and Film; Engineered Resins; Strapping; and, Fiber Applications.
These specifications assume that all other quality and processing Best Practices presented in this document have been followed. The allowable levels of the contaminants fisted in the specifications are the only types of contamination that are permitted. If a material does not have a specified level of contamination in a particular end-use category, its presence is not acceptable at any level.
Regardless of the particular specification for which you are preparing PET regrind, the following general best practices should be followed:
mark or labels boxes of regrind with weight information (gross, tare and net weights)
mark or label boxes to trace conditions of manufacture, including information to identify the supply source, the grinding equipment it was produced with, the operator who produced it, the date it was produced and any other quality data that is available
boxes should be packed and shipped in sound corrugated “gaylord” boxes and on pallets that are capable of containing approximately 900 lbs. of regrind and that will maintain their integrity in handling and shipping
all boxes should be clean to avoid contamination from previous contents
if used corrugated “gaylord” boxes are used, liners are required all boxes should be capped and strapped with Ms