Analytical Auditing Procedures for Food Contact Declarations of Conformity
Auditing food contact declarations requires matching batch numbers to accredited migration reports, verifying worst-case simulant choices, and testing NIAS.
Caprolactam Migration
Meaning
Movement of residual monomers from a nylon 6 structure into a contacting medium defines the safety profile of the polymer. The rate of caprolactam migration determines whether a material is suitable for food packaging or medical applications. It is a diffusion process driven by temperature and the nature of the stimulant.
Barrier Performance
Food contact applications must account for the speed at which chemicals exit the plastic matrix. Chemical caprolactam migration increases at higher temperatures or when the polymer touches fatty liquids. It can alter the taste of a product or exceed legal safety limits.
Health Standard
European and American regulators set specific limits on how many milligrams of the substance can enter food per kilogram of material. Testing for caprolactam migration involves soaking the part in stimulants such as acetic acid or ethanol. These tests simulate the actual shelf life of the packaged good.
Processing Influence
Resin drying and screw speed affect the amount of free monomer left in the final part. High caprolactam migration usually suggests that the material was overheated during injection moulding or the virgin pellets contained high residual levels. Proper ventilation during extrusion also helps reduce the concentrations that eventually move into the environment.
Final part quality depends on minimizing these residual levels during the melt phase.