Provided is a method of manufacturing a polyacetal copolymer including: a step of copolymerizing 100 parts by mass of trioxane (A), 0.05 to 5 parts by mass of a cyclic acetal compound (B), and 0.001 to 1 parts by mass of an aliphatic glycidyl ether compound (C) having a chlorine content of 1 to 500 mass ppm, in the presence of a linear formal compound (D) as a molecular weight regulator, in which in the step, when a total mass (g) of the trioxane (A), the compound (B), and the compound (C) is “a”, a molar number of the linear formal compound (D) is “b”, and total molar numbers of water and methanol contained in the trioxane (A), the compound (B), and the compound (C) are respectively “c” and “d”, setting is performed to satisfy (b+c+d)/a=1.5 to 7 μmol/g.

The present invention relates to a method for the deactivation of an acid catalyst during the production process of a polyoxymethylene copolymer (cPOM) by adding triisopropanolamine (tris(2-hydroxypropyl)amine) to a mixture which comprises the polyoxymethylene copolymer (cPOM) and the acid catalyst.

The present invention relates to a method for the deactivation of an acid catalyst during the production process of a polyoxymethylene copolymer (cPOM) by adding triisopropanolamine (tris(2-hydroxypropyl)amine) to a mixture which comprises the polyoxymethylene copolymer (cPOM) and the acid catalyst.

The present invention is to provide a process for producing an oxymethylene copolymer, in which deteriorate due to oxidation hardly occurs, an amount of formaldehyde generated from the product when stored for a long time under environment of high temperature and high humidity is reduced, and occurrence of mold deposit during molding is small. A process for producing an oxymethylene copolymer includes Step 1 of polymerizing polymer raw materials containing trioxane and a comonomer in the presence of a specific amount of an acid catalyst, Step 2 of adding a hydroxylamine compound represented by the following general formula (1): ##STR00001##
to a product obtained in the Step 1 in an amount of 1 to 20-fold mol based on an amount of the acid catalyst and mixing these, and
Step 3 of further melting and kneading a mixture of the product and the hydroxylamine compound obtained in the Step 2.

The present invention is to provide a process for producing an oxymethylene copolymer, in which deteriorate due to oxidation hardly occurs, an amount of formaldehyde generated from the product when stored for a long time under environment of high temperature and high humidity is reduced, and occurrence of mold deposit during molding is small. A process for producing an oxymethylene copolymer includes Step 1 of polymerizing polymer raw materials containing trioxane and a comonomer in the presence of a specific amount of an acid catalyst, Step 2 of adding a hydroxylamine compound represented by the following general formula (1): ##STR00001##
to a product obtained in the Step 1 in an amount of 1 to 20-fold mol based on an amount of the acid catalyst and mixing these, and
Step 3 of further melting and kneading a mixture of the product and the hydroxylamine compound obtained in the Step 2.

A method for producing an oxymethylene copolymer which gives molded articles that are inhibited from emitting formaldehyde and can be reduced in yellowness is provided. In producing an oxymethylene copolymer, an effective polymerization initiator amount is regulated to a value within a given range, the amount being calculated from the amount of perchloric acid or a derivative thereof contained in the polymerization initiator and the amount of triethanolamine contained in all the monomers comprising trioxane and comonomers, which are starting materials for the copolymer.

A method for producing an oxymethylene copolymer which gives molded articles that are inhibited from emitting formaldehyde and can be reduced in yellowness is provided. In producing an oxymethylene copolymer, an effective polymerization initiator amount is regulated to a value within a given range, the amount being calculated from the amount of perchloric acid or a derivative thereof contained in the polymerization initiator and the amount of triethanolamine contained in all the monomers comprising trioxane and comonomers, which are starting materials for the copolymer.

The present invention is to provide a process for producing an oxymethylene copolymer, in which deteriorate due to oxidation hardly occurs, an amount of formaldehyde generated from the product when stored for a long time under environment of high temperature and high humidity is reduced, and occurrence of mold deposit during molding is small. A process for producing an oxymethylene copolymer includes Step 1 of polymerizing polymer raw materials containing trioxane and a comonomer in the presence of a specific amount of an acid catalyst, Step 2 of adding a hydroxylamine compound represented by the following general formula (1):

##STR00001## to a product obtained in the Step 1 in an amount of 1 to 20-fold mol based on an amount of the acid catalyst and mixing these, and Step 3 of further melting and kneading a mixture of the product and the hydroxylamine compound obtained in the Step 2.

The present invention is to provide a process for producing an oxymethylene copolymer, in which deteriorate due to oxidation hardly occurs, an amount of formaldehyde generated from the product when stored for a long time under environment of high temperature and high humidity is reduced, and occurrence of mold deposit during molding is small. A process for producing an oxymethylene copolymer includes Step 1 of polymerizing polymer raw materials containing trioxane and a comonomer in the presence of a specific amount of an acid catalyst, Step 2 of adding a hydroxylamine compound represented by the following general formula (1):

##STR00001## to a product obtained in the Step 1 in an amount of 1 to 20-fold mol based on an amount of the acid catalyst and mixing these, and Step 3 of further melting and kneading a mixture of the product and the hydroxylamine compound obtained in the Step 2.

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.