| abstract |
PURPOSE: To provide the titled composition composed of a polyacetal and a block copolymer elastomer consisting of a polyacetal segment and a specific amorphous thermoplastic polymer segment, having outstanding toughness and high strength and rigidity of the polyacetal. n CONSTITUTION: The objective composition is composed of (A) 1.5W80wt% polyacetal and (B) 98.5W20wt% B 1 -B 2 -B 1 -type triblock copolymer elastomer wherein B 1 is polyacetal segment and B 2 is segment of an amorphous thermoplastic polymer having a glass transition temperature of -150W+20°C and a crystallinity of ≤30% (preferably polyether, polyester, polyamide or polysiloxane). The content of component B 2 in the segment B is preferably 1.0W60wt%. The composition can be prepared by the homopolymerization of formaldehyde or trioxane in the presence of a low-molecular compound having a number-average molecular weight of ≤500 (e.g. water, alcohol, carboxylic acid, etc.) and the above amorphous thermoplastic polymer, or by the copolymerization of formaldehyde, etc. with a cyclic ether. n COPYRIGHT: (C)1985,JPO&Japio |