Treating agent for decomposing unstable terminal group, stabilized polyacetal resin produced with the same, production process, composition, and molded object

Abstract

A process for producing a stabilized polyacetal resin which comprises heating a polyacetal resin having unstable terminal groups in the presence of a treating agent for unstable-terminal-group decomposition selected from the following groups (I), (II), and (III) to thereby diminish the unstable terminal groups. Treating agents for unstable-terminal-group decomposition in group (I) Group (I): quaternary ammonium salts of acid cyclic amide compounds Treating agents for unstable-terminal-group decomposition in group (II) Group (II): quaternary ammonium salts of polycarboxylic acids having four or more carboxy groups per molecule and / or quaternary ammonium salts of aminocarboxylic acids having one or more carboxy groups per molecule Treating agents for unstable-terminal-group decomposition in group (III) Group (III): quaternary ammonium salts in which the counter anions are ones derived from at least one compound selected from the group consisting of the following (i) to (v): (i) carbonic acid monoesters and / or metal hydrogen carbonates; (ii) acid enol compounds; (iii) phenolic compounds and alcoholic compounds; (iv) acid azole compounds; and (v) at least one noncarboxylic acid compound selected from the group consisting of organosulfur compounds, organophosphorus compounds, and organoboron compounds.

Description

technical field [0001] The present invention relates to an unstable terminal group decomposition treatment agent of a specific quaternary ammonium salt, a method for producing a stabilized polyacetal resin with a reduced unstable terminal group by heat treatment in the presence of the decomposition treatment agent, and the obtained stable polyacetal resin. Polyacetal resin, its composition and molding. Background technique [0002] Polyacetal resin has an excellent balance of mechanical properties, chemical resistance, sliding properties, etc., and is easy to process. As a representative engineering plastic, it is mainly used for electrical and electronic parts, automobile parts, and other various mechanical parts. is widely used. [0003] There are homopolymers and copolymers in polyacetal resins. The former uses formaldehyde or its cyclic polymers as raw materials, and the latter uses formaldehyde or its cyclic polymers as the main monomer to form cyclic esters and / or cyc...

AI Technical Summary

Problems solved by technology

However, some of the molecular ends of the obtained polyacetal resin are hemiacetal groups or formyl groups, which are unstable to heat, and formaldehyde is generated by thermal decomposition during molding. Oxidation into formic acid causes the following problems: decomposition of polyacetal resin, foaming of molded products, and occurrence of silver streaks due to outgassing

[0020] However, there is no description in this technique except for the residual amount of unstable terminal groups and specific quaternary ammonium sulfonic acid salts.

[0021] As above, in various existing technologies, the reduction of the residual amount of unstable terminal groups is insufficient, or a decomposition treatment agent that can achieve a balance has not been found, and the decomposition treatment agent has safety and impact on the decomposition treatment method and equipment. Not preferred restriction