Verifying Inorganic Filler Concentrations in Foreign Masterbatches Crossing Trade Borders
Verify masterbatch ash content via ISO 3451 calcination at 600°C to protect duty lines, catch mineral substitution, and prevent process failures.
Heavy Metal Limits
Meaning
Maximum concentration thresholds established by environmental protection agencies restrict the concentration of toxic elemental substances in raw polymers, masterbatches, and finished plastic products. Global regulatory bodies establish heavy metal limits under legislation like RoHS and REACH to prevent lead, cadmium, mercury, and hexavalent chromium from contaminating waste streams and consumer goods. The restriction applies to pigments and heat stabilizers present in plastic materials.
It establishes legal maximum concentration caps without prescribing specific processing parameters for injection moulders.
Regulatory Threshold
International packaging guidelines set cumulative concentration caps, restricting the sum of lead, cadmium, mercury, and hexavalent chromium to less than one hundred parts per million by weight. Enforcing heavy metal limits prevents toxic leaching when disposed plastic packaging enters municipal landfills or incineration facilities. Legacy plastic colorants based on cadmium sulfide or lead chromate are prohibited, forcing compounders to adopt organic or complex inorganic color pigments.
X-ray fluorescence spectroscopy provides rapid screening of incoming resin shipments to verify compliance before processing.
Contamination Control
Processing post-consumer recycled plastics introduces heavy metal contamination from historical pigments and electrical equipment scrap. Compounders monitoring heavy metal limits test incoming regrind batches to ensure cross-contamination does not breach legal thresholds. Contaminated recycled resin lots must be diverted away from food contact or toy manufacturing applications to prevent regulatory compliance failures.
Compliance Boundary
Compliance with elemental limits does not guarantee overall chemical safety if organic hazardous substances like phthalates remain present. Polymer processors perform comprehensive chemical screening to confirm full regulatory adherence.