POLYACETAL HOMOPOLYMER MOLDING

摘要

PURPOSE:To obtain the molding having the sphaerite grown to its surface by a method wherein a polyacetal homopolymer molding substantially free from skin layer is formed by using a die having the wall surface covered with a specific heat insulating layer and a specific polymer. CONSTITUTION:The polyacetal homopolymer molding substantially free from skin layer is formed by using a main die consisting of metal and having the surface of the walls defining the die cavity covered with a heat insulating layer constituted of a heat resisting polymer having a heat conductivity of at most 0.002cal/cm.sec. deg.C and built up to a thickness of 0.01-2mm and a polymer having an average molecular weight of 18000-100000 and having its terminal portion consisting of an acetyl group in an amount of from 60% to less than 99%. The molding consisting of crystalline resin such as polyacetal has a poor lubricating performance due to the noncrystallinity or low crystallinity of the skin layer present on its surface. Therefore, the lubricating performance of the molding substantially free from the skin layer is good.