The present invention provides a polyacetal resin composition comprising (A) a polyacetal resin and (B) zinc oxide, wherein the content of oxyalkylene constituent units other than an oxymethylene group in the polyacetal resin (A) is 0.1% by mass or more, and wherein the total surface area of the zinc oxide (B) in the polyacetal resin composition is 0.1 to 40 m.sup.2 per 100 g of the polyacetal resin (A); as well as an article molded therefrom.

A polyoxymethylene (POM) resin composition which is used for a resin molded article having an excellent sliding characteristic and wear resistance property and also having an excellent surface property and peeling resistance property. This POM resin composition contains: (A) 100 parts by mass of a POM resin; (B) 0.01-1 parts by mass of a hindered phenolic antioxidant; (C) 0.05-1 parts by mass inclusive of a nitrogen-containing compound; (D) 0.5-10 parts by mass of a modified olefin polymer which is an olefin polymer that has been modified by an unsaturated carboxylic acid or the like; (E) 0.01-5 parts by mass of an alkylene glycol polymer that has a primary or secondary amino group and a number average molecular weight of 400-500,000; (F) 0.1-20 parts by mass of calcium carbonate which has a BET specific surface area of 15 m2/g or less, has a mean particle size of 50-200 nm or less, is surface-untreated, and is substantially cubic; (G) 0.1-10 parts by mass of a partial ester of a divalent to tetravalent alcohol; and (H) 0.1-10 parts by mass of an α-olefin oligomer.

A polyoxymethylene (POM) resin composition which is used for a resin molded article having an excellent sliding characteristic and wear resistance property and also having an excellent surface property and peeling resistance property. This POM resin composition contains: (A) 100 parts by mass of a POM resin; (B) 0.01-1 parts by mass of a hindered phenolic antioxidant; (C) 0.05-1 parts by mass inclusive of a nitrogen-containing compound; (D) 0.5-10 parts by mass of a modified olefin polymer which is an olefin polymer that has been modified by an unsaturated carboxylic acid or the like; (E) 0.01-5 parts by mass of an alkylene glycol polymer that has a primary or secondary amino group and a number average molecular weight of 400-500,000; (F) 0.1-20 parts by mass of calcium carbonate which has a BET specific surface area of 15 m2/g or less, has a mean particle size of 50-200 nm or less, is surface-untreated, and is substantially cubic; (G) 0.1-10 parts by mass of a partial ester of a divalent to tetravalent alcohol; and (H) 0.1-10 parts by mass of an α-olefin oligomer.

A polyoxymethylene (POM) resin composition which is used for a resin molded article having a superior sliding characteristic. This POM resin composition contains: (A) 100 parts by mass of a POM resin; (B) 0.01-1 parts by mass of a hindered phenolic antioxidant; (C) 0.05-1 parts by mass of a nitrogen-containing compound; (D) 0.5-10 parts by mass of a modified olefin polymer; (E) 0.01-5 parts by mass of an alkylene glycol polymer; (F) 0.1-20 parts by mass of calcium carbonate; (G) 0.1-10 parts by mass of a partial ester of a polyhydric alcohol; and (H) 0.1-10 parts by mass of an α-olefin oligomer.

A polyoxymethylene (POM) resin composition which is used for a resin molded article having a superior sliding characteristic. This POM resin composition contains: (A) 100 parts by mass of a POM resin; (B) 0.01-1 parts by mass of a hindered phenolic antioxidant; (C) 0.05-1 parts by mass of a nitrogen-containing compound; (D) 0.5-10 parts by mass of a modified olefin polymer; (E) 0.01-5 parts by mass of an alkylene glycol polymer; (F) 0.1-20 parts by mass of calcium carbonate; (G) 0.1-10 parts by mass of a partial ester of a polyhydric alcohol; and (H) 0.1-10 parts by mass of an α-olefin oligomer.

It has been desired to develop a method for producing an oxymethylene polymer, by which an oxymethylene polymer having a high polymerization degree can be produced with high efficiency while suppressing increase in the amount of generation of an odor. Further, it has been desired to develop an oxymethylene polymer resin composition, wherein generation of an odor at the time of molding or after molded to obtain a molded body is suppressed. The present invention provides a method for producing an oxymethylene polymer, wherein the oxymethylene polymer is produced by polymerizing a cyclic oligomer of formaldehyde, and wherein a boron trifluoride compound and an aryl fluoride boron compound are used as polymerization catalysts. The present invention also provides an oxymethylene polymer resin composition containing an oxymethylene polymer and a derivative of an aryl fluoride boron compound.

It has been desired to develop a method for producing an oxymethylene polymer, by which an oxymethylene polymer having a high polymerization degree can be produced with high efficiency while suppressing increase in the amount of generation of an odor. Further, it has been desired to develop an oxymethylene polymer resin composition, wherein generation of an odor at the time of molding or after molded to obtain a molded body is suppressed. The present invention provides a method for producing an oxymethylene polymer, wherein the oxymethylene polymer is produced by polymerizing a cyclic oligomer of formaldehyde, and wherein a boron trifluoride compound and an aryl fluoride boron compound are used as polymerization catalysts. The present invention also provides an oxymethylene polymer resin composition containing an oxymethylene polymer and a derivative of an aryl fluoride boron compound.

It has been desired to develop a method for producing an oxymethylene polymer, by which an oxymethylene polymer having a high polymerization degree can be produced with high efficiency while suppressing increase in the amount of generation of an odor. Further, it has been desired to develop an oxymethylene polymer resin composition, wherein generation of an odor at the time of molding or after molded to obtain a molded body is suppressed. The present invention provides a method for producing an oxymethylene polymer, wherein the oxymethylene polymer is produced by polymerizing a cyclic oligomer of formaldehyde, and wherein a boron trifluoride compound and an aryl fluoride boron compound are used as polymerization catalysts. The present invention also provides an oxymethylene polymer resin composition containing an oxymethylene polymer and a derivative of an aryl fluoride boron compound.

The present invention addresses the problem of providing a method for producing an oxymethylene copolymer, which is capable of producing an oxymethylene copolymer having a high molecular weight with high yield and high economic efficiency. This problem is able to be solved by a method for producing an oxymethylene copolymer, in which a copolymer starting material containing a trioxane and a comonomer is subjected to a polymerization reaction in the presence of a polymerization initiator that contains an acidic compound (A), and wherein: the copolymer starting material contains a basic compound (B); an acidic compound (C) that is different from the acidic compound (A) is added into the copolymer starting material before performing the polymerization reaction, thereby causing a reaction between the basic compound (B) and the acidic compound (C) in advance; and the polymerization reaction is carried out by means of melt polymerization.

A polyoxymethylene (POM) resin composition which is used for a resin molded article having a superior sliding characteristic. The POM resin composition contains: (A) 100 parts by mass of a POM resin; (B) 0.01-1 parts by mass of a hindered phenolic antioxidant; (C) 0.05-1 parts by mass of a nitrogen-containing compound; (D) 0.5-10 parts by mass of a modified olefin polymer; (E) 0.01-5 parts by mass of an alkylene glycol polymer; (F) 0.1-20 parts by mass of calcium carbonate; (G) 0.1-10 parts by mass of a partial ester of a polyhydric alcohol; and (H) 0.1-10 parts by mass of an a-olefin oligomer. An ISO tensile test piece, which is obtained by injection molding at a die temperature of 90° C. and a cylinder temperature of 200° C., is crushed, Soxhlet extraction is performed for 3 hours at 70° C. using methanol, and the alkylene glycol polymer is measured. The weight of the alkylene glycol polymer is 0.001 wt % or less relative to 100 wt % of the test piece.