Polyethylene naphthalate

A polyester polymer whose characteristics suit it to food packaging, closely related to PET but with better oxygen barrier, stiffness, and resistance to heat and chemicals, though at higher cost. Its physical and mechanical traits suit it to refillable containers and hot-fill applications, and it is sometimes mixed with PET for plastic food and beverage containers, notably beer bottles, where oxygen exclusion protects flavor. As a food-contact plastic it must satisfy the same migration and safety evaluations as other packaging polymers, with testing under realistic conditions of use.