Abstract: A polyacetal resin composition. An aliphatic polycarboxylic acid having four or more carbons and two or more carboxyl groups and a hindered-phenol antioxidant are incorporated into a polyacetal copolymer obtained by copolymerizing trioxane as a major monomer with a cyclic ether and/or cyclic formal each having at least one carbon-carbon bond as a comonomer using a specific heteropoly acid as a polymerization catalyst, adding, to the resultant reaction product, a compound which is any of the carbonates, hydrogen carbonates, and carboxylates of alkali metal elements or alkaline-earth metal elements, the hydrates of these, and the hydroxides of alkali metal elements or alkaline-earth metal elements, and melt-kneading the mixture to deactivate the polymerization catalyst.

Abstract: A method for producing a dust-resistant sliding member, the method including a step of preparing a resin composition containing 0.5 to 5.0 parts by mass of a specific lubricant that is liquid at 25° C., 0.1 to 30 parts by mass of an inorganic filler, 1.0 to 20 parts by mass of a specific modified olefin-based polymer, and 0.01 to 5.0 parts by mass of an alkylene glycol-based polymer having a primary or secondary amino group, per 100 parts by mass of a polyacetal copolymer containing oxyalkylene units in a ratio of 0.4 to 0.9 mol % relative to all of the structural units; and a step of molding the resin composition into a prescribed shape.

Abstract: A method for producing a dust-resistant sliding member, the method including a step of preparing a resin composition containing 0.5 to 5.0 parts by mass of a lubricant that is liquid at 25° C. and is composed of at least one material selected from the group consisting of ethylene/?-olefin copolymers, poly-?-olefins and silicones, and 0.1 to 30 parts by mass of an inorganic filler, per 100 parts by mass of a polyacetal resin, and a step of molding the resin composition into a prescribed shape.

Abstract: A polyacetal resin composition containing 100 parts by weight of a polyacetal resin; from 0.01 part by weight to 0.5 part by weight (inclusive) of a hindered phenolic antioxidant; from 0.002 part by weight to 0.02 part by weight (inclusive) of an aliphatic carboxylic acid containing 2 or more carboxyl groups and having 4 or more carbon atoms; and from 0.01 part by weight to 0.1 part by weight (inclusive) of a fatty acid calcium salt. The molar ratio of the fatty acid calcium salt to the aliphatic carboxylic acid may be from 0.5 to 5 (inclusive).

Abstract: A production method for a polyacetal copolymer that makes deactivation of a catalyst simple and efficient and that achieves a high polymerization yield and high quality using equipment that does not require a cleaning step and a process that involves a simple operation technique. The production method for a polyacetal copolymer uses trioxane as a main monomer and a cyclic ether and/or a cyclic formal having at least one carbon-carbon bond as a comonomer. In the production method, a predetermined heteropoly acid is used as a polymerization catalyst to perform copolymerization, a predetermined salt is added to the reaction product, melt kneading processing is performed, and the polymerization catalyst is deactivated.

Abstract: A high-quality polyacetal copolymer produced by a simple process and in an economical manner. The method includes supplying a raw material including trioxane or the like to a reaction device; obtaining a reaction mixture by carrying out a polymerization reaction of the raw material in the state where the rotating shafts are inclined by 1 to 6° upwards with respect to the horizontal direction H from the introduction opening towards a polyacetal copolymer recovery portion; vaporizing and separating an unreacted monomer from the reaction mixture using a vaporization and separation portion; re-supplying the unreacted monomer to the reaction device; and recovering the polyacetal copolymer from the reaction using a polyacetal copolymer recovery portion.

Abstract: A high-quality polyacetal copolymer produced by a simple process in an economical manner. The process includes supplying a raw material including trioxane and the like to a reaction device; setting the polymerization environmental temperature to no more than 100° C. until the reaction device conversion rate becomes 0.5, and then carrying out further polymerization; vaporizing and separating unreacted monomers from the reaction mixture at an environmental temperature of at least 115° C. and less than 140° C.; supplying the separated monomers to the raw material supply; and recovering the polyacetal copolymer from the reaction mixture.

Abstract: A production method for a polyacetal copolymer that makes deactivation of a catalyst simple and efficient and that achieves a high polymerization yield and high quality using equipment that does not require a cleaning step and a process that involves a simple operation technique. The production method for a polyacetal copolymer uses trioxane as a main monomer and a cyclic ether and/or a cyclic formal having at least one carbon-carbon bond as a comonomer. In the production method, a predetermined heteropoly acid is used as a polymerization catalyst to perform copolymerization, a predetermined salt is added to the reaction product, melt kneading processing is performed, and the polymerization catalyst is deactivated.

Abstract: A polyoxymethylene resin composition from which formaldehyde is generated in a reduced amount upon molding, without carrying out a stabilization treatment for stabilizing an unstable terminal group in a crude oxymethylene copolymer. A hindered phenol-type antioxidant agent and an ethylene-(methacrylic acid) copolymer resin or an ethylene-(acrylic acid) copolymer resin or a salt thereof are melted and kneaded together to produce a polyoxymethylene resin composition without carrying out a stabilization treatment for stabilizing an unstable terminal group in a crude oxymethylene copolymer for which a polymerization catalyst is deactivated after the completion of copolymerization and in which the unstable terminal group is not yet stabilized. When the polyoxymethylene resin composition is extrusion-molded, the discoloration of a molded product or the deterioration in properties of the molded product can be prevented for a long period of time.

Abstract: A high-quality polyacetal copolymer produced by a simple process in an economical manner. The process includes supplying a raw material including trioxane and the like to a reaction device; setting the polymerization environmental temperature to no more than 100° C. until the reaction device conversion rate becomes 0.5, and then carrying out further polymerization; vaporizing and separating unreacted monomers from the reaction mixture at an environmental temperature of at least 115° C. and less than 140° C.; supplying the separated monomers to the raw material supply; and recovering the polyacetal copolymer from the reaction mixture.

Abstract: A high-quality polyacetal copolymer produced by a simple process and in an economical manner. The method includes supplying a raw material including trioxane or the like to a reaction device; obtaining a reaction mixture by carrying out a polymerization reaction of the raw material in the state where the rotating shafts are inclined by 1 to 6° upwards with respect to the horizontal direction H from the introduction opening towards a polyacetal copolymer recovery portion; vaporizing and separating an unreacted monomer from the reaction mixture using a vaporization and separation portion; re-supplying the unreacted monomer to the reaction device; and recovering the polyacetal copolymer from the reaction using a polyacetal copolymer recovery portion.

Abstract: An object of the present invention is to provide a polyacetal resin composition having excellent friction and abrasion characteristics and having improved mechanical strength. Specifically, there are blended (A1) 100 parts by weight of a polyacetal resin having substantially straight chain molecular structure; (A2) 0.1 to 20 parts by weight of a polyacetal resin having branched or crosslinked molecular structure; and (B) 0.05 to 20 parts by weight of a lubricant oil keeping liquid state at 200° C.