MANUFACTURE OF MULTI-LAYERED CONTAINER

摘要

PURPOSE:To obtain a PET container excellent in gas permeation resistance and impact resistance, by biaxially stretching and blow molding a preform that has been prepared by laminating a polyethylene terephthalate (PET) and a polyester in a melted state under specified conditions that has been prepared using isophthalic acid as a major raw material. CONSTITUTION:A melted PET at 230-300 deg.C and a melted polyester at 180- 260 deg.C that consists of a dicarboxylic acid constituent containing at least more than 20mol% of isophthalic acid and ethylene glycol as major constituent are laminated under a molding pressure (gauge pressure) of 20kg/cm<2> or more. The laminate is cooled and solidified at a cooling temperature of -10-30 deg.C to provide a preform made up of a PET layer and a polyester layer. Thereafter, the preform is biaxially stretched and blow molded at a stretching temperature of 80-130 deg.C with the degree of the stretching at least 1.5 times longitudinally and at least 2 times laterally to obtain a multi-layer container mainly made of PET excellent in gas permeation resistance and impact resistance.