Meaning
Thermoplastic resin recovered from post-industrial scrap or post-consumer waste streams is cleaned, pelletized, and prepared for compounding into new molded parts. When processing recycled polycarbonate, compounders must manage the reductions in molecular weight caused by previous heat cycles and environmental exposure. This material offers an attractive carbon footprint reduction but requires careful blending and stabilizing to match the mechanical standards of virgin equivalents.
Sourcing Cost
Mixing recovered material with virgin resin lowers the average raw material cost per kilogram for the moulder. However, the economics of recycled polycarbonate depend heavily on the sorting and cleaning processes used to eliminate contaminants such as paper, adhesives, or other polymers. If the contamination levels are too high, the savings are offset by increased machine downtime and scrap rates during the moulding process.
Moulding Challenge
Hydrolytic degradation during the melt phase is more severe in recovered resins due to the higher levels of residual moisture and acidic contaminants they contain. When a moulder processes recycled polycarbonate, the material requires longer drying times at high temperatures to prevent hydrolysis from reducing the impact strength of the molded parts. This degradation shows up as a low melt viscosity, which can cause flashing at the mold parting line and voids in the thick sections of the part.
Moulders must reduce the injection speed and adjust the injection pressure to compensate for these melt variations.
Quality Verification
Testing the melt flow rate and density of the incoming batches ensures that the reprocessed resin meets the physical specifications of the application. This verification step prevents the accidental moulding of brittle parts.
