| abstract |
A heat insulator made of shape memory polymer foam which has good moldability and changes greatly in elastic modulus above and below its glass transition point, and a heat insulator as mentioned above in which the polymer foam is polyurethane produced by prepolymer process from a composition containing a blowing agent, said composition being composed of a difunctional diisocyanate, a difunctional polyol, and a difunctional chain extender containing active hydrogen in a molar ratio of 2.00-1.10:1.00:1.00-0.10, said polyurethane containing approximately equal amounts of NCO groups and OH groups at the terminals of the molecular chains and having a glass transition point of -50° to 60° C. and crystallinity of 3 to 50 wt %. |