Migration of residual contaminants from secondary recycled poly(ethylene terephthalate) into food‐simulating solvents, aqueous ethanol and heptane

Abstract

This study measured the migration of benzene, butyric acid, dodecane, octadecane, tetracosane, diazinon, lindone, and copper (II) ethyl hexanoate from poly (ethylene terephthalate) (PETE) sheets into the food simulants, 8% ethanol/water and n‐heptane. The contaminated PETE sheets were extruded from PETE chips that had been previously contaminated but were washed, dried, and remelted. The level of these contaminants remaining in the extruded sheets ranged from benzene at 0.6 mg/kg to copper salt at 24 mg/kg. The extraction data demonstrate that migration of the residual contaminants from the extruded PETE sheets resulted in concentrations lower than 10 fig/kg in the food simulants. At very high residual concentrations of butryic acid (147 mg/kg) and benzene (218 mg/kg) in sheets made from unwashed PETE, higher amounts of the contaminant migrated into the food simulants. This migration resulted in contaminant concentrations exceeding 10 μg/kg and suggests that unwashed recycled PETE may not comply with FDA requirements. The crystallinity of extruded PETE sheets in this study ranged from 5 to 15%, which is lower than that of most commercial PETE (30%). Therefore, the migration data obtained from these test samples represent the most severe conditions for conservative exposure evaluations.