Process for the removal of volatile compounds from a tackifier comprising a resin with repeating units of formula I wherein R.sup.1 is a linear or branched alkylen group with 1 to 10 carbon atoms and R.sup.2 is a linear or branched, saturated or unsaturated N aliphatic hydrocarbon group with up to 20 carbon atoms, and optionally a plasticizer, wherein the tackifier is passed through at least one evaporator as film and the volatile compounds are removed from the film.

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An oxymethylene-copolymer manufacturing method includes: polymerizing a polymerization raw material containing trioxane and a comonomer in the presence of an acid catalyst in a quantity that is 1.010.sup.8 moles to 5.010.sup.6 moles with respect to 1 mole of trioxane; adding a hydroxylamine compound represented by general formula (1) (in the formula, R.sup.1 and R.sup.2 are, independently of each other, a hydrogen atom or an organic group having 1-20 carbon atoms) to a reaction product obtained during the polymerizing of the polymerization raw material at 50-5000 times the quantity of the acid catalyst, in terms of the molar quantity, and mixing the hydroxylamine compound with the reaction product; and for subjecting the mixture of the reaction product and the hydroxylamine compound, which is obtained during the adding of the hydroxylamine compound, to an additional melt-kneading.

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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 process for forming stabilizing paraformaldehyde can include heating a formaldehyde solution comprising 30 wt % or more formaldehyde to a temperature ranging from about 70 C. to about 130 C.; aging the formaldehyde solution for a sufficient amount of time to polymerize the formaldehyde and form paraformaldehyde; solidifying the paraformaldehyde; and contacting the formaldehyde solution before and/or during heating, the formaldehyde solution during aging, the paraformaldehyde, and/or the solidified paraformaldehyde with an ammonia and/or ammonia hydroxide stabilizer.

A process for forming stabilizing paraformaldehyde can include heating a formaldehyde solution comprising 30 wt % or more formaldehyde to a temperature ranging from about 70 C. to about 130 C.; aging the formaldehyde solution for a sufficient amount of time to polymerize the formaldehyde and form paraformaldehyde; solidifying the paraformaldehyde; and contacting the formaldehyde solution before and/or during heating, the formaldehyde solution during aging, the paraformaldehyde, and/or the solidified paraformaldehyde with an ammonia and/or ammonia hydroxide stabilizer.

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.

An oxymethylene-copolymer manufacturing method includes: polymerizing a polymerization raw material containing trioxane and a comonomer in the presence of an acid catalyst in a quantity that is 1.0?10.sup.?8 moles to 5.0?10.sup.?6 moles with respect to 1 mole of trioxane; adding a hydroxylamine compound represented by general formula (1) (in the formula, R.sup.1 and R.sup.2 are, independently of each other, a hydrogen atom or an organic group having 1-20 carbon atoms) to a reaction product obtained during the polymerizing of the polymerization raw material at 50-5000 times the quantity of the acid catalyst, in terms of the molar quantity, and mixing the hydroxylamine compound with the reaction product; and subjecting the mixture of the reaction product and the hydroxylamine compound, which is obtained during the adding of the hydroxylamine compound, to an additional melt-kneading. ##STR00001##

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 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.