Nylon (polyamide) is a polymer polymerized by amide bonds and includse nylon 6 (a polymer of ε-caprolactam) and nylon 66 (a polymer of hexamethylenediamine and adipic acid). Nylon has excellent mechanical strength, such as tensile strength, tear strength, and stick strength, it is used in food packaging materials such as chilled frozen and retort foods.

In this application, packaging materials for commercially available frozen foods were extracted by immersion in an aqueous ethanol solution and eluted. Measurements were made according to the hygiene test method. A standard additive was also measured.