A polyoxymethylene resin molded article comprising 100 parts by mass of a polyoxymethylene resin (A) and 0.1 to 5 parts by mass of a sliding agent (B), wherein four or more dispersion domains of the sliding agent (B) are present in a region of 1000 nm in depth from a surface of the molded article and 12000 nm in width, and the dispersion domain has an average minor diameter of 300 nm or less, and an average major diameter of 600 nm or more and 5000 nm or less.

Polyoxymethylene-polydimethysiloxane block copolymers are disclosed. In one embodiment, the siloxane monomer used to make the polymer is soluble in the polyoxymethylene monomers, namely trioxane. The polymer can be formed having relatively small particle sizes, such as less than about 350 microns, such as less than about 200 microns, which makes the polymer well suited for powder coating applications.

Long chain branched polyoxymethylene-polydimethylsiloxane copolymers are described. The copolymers have excellent impact properties, shear thinning and slip wear properties in comparison to a polyoxymethylene polymer not containing polydimethylsiloxane groups.

A polyoxymethylene resin molded article comprising 100 parts by mass of a polyoxymethylene resin (A) and 0.1 to 5 parts by mass of a sliding agent (B), wherein four or more dispersion domains of the sliding agent (B) are present in a region of 1000 nm in depth from a surface of the molded article and 12000 nm in width, and the dispersion domain has an average minor diameter of 300 nm or less, and an average major diameter of 600 nm or more and 5000 nm or less.

The invention relates to a process for producing polyoxymethylene block copolymers, comprising the step of activating the DMC catalyst in the presence of an OH-terminated polymeric formaldehyde starter compound by means of a defined amount of alkylene oxide, optionally followed by polymerization with alkylene oxides, if necessary in the presence of other comonomers. The invention further relates to polyoxymethylene block copolymers that can be obtained by means of such a process and to the use of these for producing polyurethane polymers.

An object of the invention is to provide a resin composition, from which a molded article having high durability, sliding property and wear resistance can be produced with a high productivity.

The present invention provides a polyacetal resin composition containing 100 parts by mass of a polyacetal resin (A) and 10 parts by mass or more and 100 parts by mass or less of a glass filler (B), in which when a molded article formed of the polyacetal resin composition by molding is fractured by application of tensile force, the surface of the glass filler (B) protruding from a fractured surface of a fractured molded article is covered with a component containing the polyacetal resin (A) having an average thickness of 0.2 m or more and 3.0 m or less.

An object of the invention is to provide a resin composition, from which a molded article having high durability, sliding property and wear resistance can be produced with a high productivity.

The present invention provides a polyacetal resin composition containing 100 parts by mass of a polyacetal resin (A) and 10 parts by mass or more and 100 parts by mass or less of a glass filler (B), in which when a molded article formed of the polyacetal resin composition by molding is fractured by application of tensile force, the surface of the glass filler (B) protruding from a fractured surface of a fractured molded article is covered with a component containing the polyacetal resin (A) having an average thickness of 0.2 m or more and 3.0 m or less.

An object of the present disclosure is to provide a composition containing a modified polyacetal suitable for applications of inorganic powder injection molding. A composition for inorganic powder injection molding of the present disclosure includes a sinterable inorganic powder and an organic binder containing a modified polyacetal (C) including a polyacetal segment (A) and a modification segment (B), wherein the number average molecular weight of the above modification segment (B) is 500 to 10000.

The invention relates to a method for producing a polyoxymethylene polyoxyalkylene block copolymer, said method including the process of reacting a polymer formaldehyde compound with alkylene oxide in the presence of a double metal cyanide (DMC) catalyst and an H-functional starter substance, wherein the theoretical molar mass of the polymer formaldehyde compound is lower than the theoretical molar mass of the H-functional starter substance, and the polymer formaldehyde compound has at least one terminal hydroxyl group, the theoretical molar mass of the H-functional starter substance being at least 500 g/mol. In the method according to the invention, a mixture i) is provided comprising the DMC catalyst and the H-functional starter substance in step (i); the polymer formaldehyde compound is then added to the mixture (i) in step (ii), thereby forming a mixture (ii); and the alkylene oxide is added in step (iii), step (ii) being carried out at the same time as or prior to step (iii).

The invention relates to a method for producing a polyoxymethylene polyoxyalkylene block copolymer, said method including the process of reacting a polymer formaldehyde compound with alkylene oxide in the presence of a double metal cyanide (DMC) catalyst and an H-functional starter substance, wherein the theoretical molar mass of the polymer formaldehyde compound is lower than the theoretical molar mass of the H-functional starter substance, and the polymer formaldehyde compound has at least one terminal hydroxyl group, the theoretical molar mass of the H-functional starter substance being at least 500 g/mol. In the method according to the invention, a mixture i) is provided comprising the DMC catalyst and the H-functional starter substance in step (i); the polymer formaldehyde compound is then added to the mixture (i) in step (ii), thereby forming a mixture (ii); and the alkylene oxide is added in step (iii), step (ii) being carried out at the same time as or prior to step (iii).