| 摘要 |
<p>PURPOSE: To obtain high impact strength, practical temp. and heat insulating properties by heating a foam sheet of polypropylene having a specific MZ or MZ/MW ratio and equilibrium compliance or specific restorable shearing strain to deformable temp. to soften the same and molding the heated sheet into a hard or semihard article. CONSTITUTION: A foam sheet is obtained from a polyproplene resin having an MZ value higher than 1.0×10<6> , an MZ/MW ratio higher than 3.0 and an equilibrium compliance Jeo value of above 1.2×10<-3> m<2> /N or restorable shearing strain Sr/S per stress higher than 5.0×10<-4> m<2> /N at 1 sec<-1> and aged for a definite time to expand a blowing agent. In the case of secondary processing, air is passed through cell walls before this processing to achieve equilibrium. The polypropylene foam sheet has an outer layer or skin almost free from cells and shows glassy appearance and has resistance against surface abrasion and cutting and also has bending rigidity.</p> |
