A process for making an oxymethylene polymer comprising polymerizing at least one compound capable of forming CH.sub.2O repeat units (monomer) in the presence of at least one ester of the general formula I (ester): R.sup.1COOR.sup.2 (I) wherein R.sup.1 can be hydrogen, wherein R.sup.1 and R.sup.2 are independently of each other linear or branched C.sub.1 to C.sub.10 alkyl C.sub.5 to C.sub.7 cycloalkyl [R.sup.3-0-].sub.nR.sup.4 wherein R.sup.3 is a linear or branched C.sub.2 to C.sub.5 alkylen and R.sup.4 is a linear of branched C.sub.1 to C.sub.5 alkyl and n is an integer of from 1 to 5. and in the presence of at least one Lewis acid.

A process for making an oxymethylene polymer comprising polymerizing at least one compound capable of forming CH.sub.2O repeat units (monomer) in the presence of at least one ester of the general formula I (ester): R.sup.1COOR.sup.2 (I) wherein R.sup.1 can be hydrogen, wherein R.sup.1 and R.sup.2 are independently of each other linear or branched C.sub.1 to C.sub.10 alkyl C.sub.5 to C.sub.7 cycloalkyl [R.sup.3-0-].sub.nR.sup.4 wherein R.sup.3 is a linear or branched C.sub.2 to C.sub.5 alkylen and R.sup.4 is a linear of branched C.sub.1 to C.sub.5 alkyl and n is an integer of from 1 to 5. and in the presence of at least one Lewis acid.

An oxymethylene copolymer resin composition, which includes (i) an oxymethylene copolymer, (ii) a derivative of an aryl boron fluoride compound, and (iii) a layered double hydroxide; and a method for producing the same.

Polyoxymethylene, where a ratio of a low molecular weight component having a molecular weight of 10,000 or less in a molecular weight distribution is 7.0% or less of the total, and the molecular weight distribution is obtained by measurement by gel permeation chromatography (GPC) using polymethyl methacrylate (PMMA) as a standard substance.

Polyoxymethylene, where a ratio of a low molecular weight component having a molecular weight of 10,000 or less in a molecular weight distribution is 7.0% or less of the total, and the molecular weight distribution is obtained by measurement by gel permeation chromatography (GPC) using polymethyl methacrylate (PMMA) as a standard substance.

The present invention provides a method for producing an oxymethylene copolymer which involves polymerizing trioxane and a comonomer cationically at a polymerization temperature of 135 C. to 300 C. in the presence of a protic acid salt having the molecular weight of 1000 or less, and at least one polymerization initiator selected from the group consisting of protic acids, protic acid anhydrides, and protic acid ester compounds having the molecular weight of 1000 or less.

The present invention provides a method for producing an oxymethylene copolymer which involves polymerizing trioxane and a comonomer cationically at a polymerization temperature of 135 C. to 300 C. in the presence of a protic acid salt having the molecular weight of 1000 or less, and at least one polymerization initiator selected from the group consisting of protic acids, protic acid anhydrides, and protic acid ester compounds having the molecular weight of 1000 or less.

The invention provides a method for producing an oxymethylene copolymer including a polymerization step for cationically polymerizing trioxane and a comonomer at a polymerization temperature of from 135 to 300 C. in the presence of at least one salt of a protonic acid having a molecular weight of 1,000 or less, and at least one polymerization initiator selected from the group consisting of protonic acids having a molecular weight of 1,000 or less, protonic acid anhydrides having a molecular weight of 1,000 or less, and protonic acid ester compounds having a molecular weight of 1,000 or less; wherein the total concentration of metal components contained in the trioxane and comonomer used in the polymerization step is 300 ppb by mass or less.

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).