Best Practices in PET Recycling
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Clear PET, Clean Flake Specifications
for Fiber, Bottles, Film and Sheet, Strapping,
Engineered Resins, and Depolymerization
Issue: Successful conversion of recycled PET into end products requires a high quality resin that meets demanding product specifications and strict processing requirements, consistent and cost-effective manufacturing. Suppliers of post-consumer clean PET flake can sell into major PET applications only if the product meets customer specifications.
Background: The goal of this effort is to establish a level of industry consensus on post-consumer, clean flake specifications. While this set of target quality specifications may be acceptable to most PET end-users, it is incumbent upon suppliers to determine unique or different specifications that their customers require. To develop this set of quality specifications, a list of proposed specifications for post-consumer PET was sent to end-users who manufacture a variety of industrial and consumer products and applications, including: Fiber, Bottles, Sheet and Film, Strapping, Engineered Resins, and Depolymerization. Each end-user modified the proposed specifications to reflect quality standards that suppliers must meet. Quality test methods are shown as "internal" when this information was not provided.
Best Practices: These post-consumer clean PET flake specifications are not intended to meet any one company's individual specifications. They do, however, represent a standard that will be acceptable to most PET purchasers and a quality target that can reduce the cost of the PET recycling process. End-product manufacturers may identify specific variations that are required by their process or end-product. As a general rule, higher valued applications have more stringent specifications for post-consumer clean PET flake. This is particularly true for Intrinsic Viscosity, particulate contaminants, and PVC. The contaminants listed in the specifications are the only impurities permitted. By their omission, other contaminants are deemed unacceptable at any level. Ranges of contaminants are provided to allow for requirements of different end-product manufacturers in the same industry.
Benefits: These specifications are compiled by cooperation from industrial purchasers of recycled PET. Production of clear recycled PET flake that meets the above standard specifications will increase the marketability of clean flake. Contact: For more information, contact CWC at (206) 443-7746 or e-mail at info@cwc.org. Issue Date / Update: January 1998
CLEAR PET FLAKE – FIBER SPECIFICATIONS
| Property | Specification | Test Method |
| Intrinsic Viscosity (dL/gm) | 0.65 min | ASTM D4603 |
| Particle Size (inch) | 3/8 – 5/8 | Internal |
| Bulk Density (lbs/ft 3 ) | 20 - 32 | Internal |
| Moisture Content (%) | < 1.0 | Internal |
| Maximum Contaminant Levels (ppm): | ||
| Aluminum | 50 | Internal |
| Labels | 10 | Internal |
| Low Melts | 1000 | Internal |
| PVC | 200 | Internal |
| EVOH | Nil | Internal |
| PP/HDPE | 50 | Internal |
| Residual Glue | N/A | N/A |
| Black | 160 | Internal |
| Green | 3000 | Internal |
| Total Color (excluding black) | 5000 | Internal |