Forming seat cushion, armrest, headrest, etc. for vehicle by lining mold cavity with thermoplastic film and injecting polyurethane to form foam that plastifies and partly penetrates film

摘要

Forming an article by lining a mold cavity with a thermoplastic film before injecting polyurethane that expands into a foam. The film is initially permeable to water vapor and contains agents that react with isocyanate in the polyurethane to plastify the film. The film is sufficiently thick that the pressure generated by the expanding foam makes the foam only partly penetrate the film. The film may includes a plastifying agent, e.g. paper or see below. The film is 25 - 80 micro m thick, has a fusion point of 60 - 150 deg C, dissolves in isocyanate <= 10 minutes at 20 - 80 deg C and has air permeability <= 1 l/m<2>/sec at a pressure difference of 100 Pa.