| 摘要 |
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. CONSTITUTION:The objective composition is composed of (A) 1.5-80wt% polyacetal and (B) 98.5-20wt% B1-B2-B1-type triblock copolymer elastomer wherein B1 is polyacetal segment and B2 is segment of an amorphous thermoplastic polymer having a glass transition temperature of -150-+20 deg.C and a crystallinity of <=30% (preferably polyether, polyester, polyamide or polysiloxane). The content of component B2 in the segment B is preferably 1.0-60wt%. 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. |
