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.

Potentially degradable isohexide based compounds and their polymers, derived from renewable resources, are described. Degradable isohexide-based monomers and polymers obtained from renewable resources are also described. Finally, processes for synthesizing such degradable polymers via copolymerization of the isohexide-based monomers and long chain diols are disclosed.

Potentially degradable isohexide based compounds and their polymers, derived from renewable resources, are described. Degradable isohexide-based monomers and polymers obtained from renewable resources are also described. Finally, processes for synthesizing such degradable polymers via copolymerization of the isohexide-based monomers and long chain diols are disclosed.

The patent application relates to a process for preparing polyoxymethylene by polymerization of a reaction mixture (R.sub.G) which comprises at least one formaldehyde source and at least one initiator mixture (I.sub.G), wherein the initiator mixture (I.sub.G) comprises at least one polymerization initiator and at least one solvent of the general formula (I)
R.sup.1—O—[—R.sup.3—O—].sub.m—R.sup.2  (I), where m is 1, 2, 3 or 4; R.sup.1 and R.sup.2 are each, independently of one another, C.sub.3-C.sub.6-alkyl; R.sup.3 is C.sub.1-C.sub.5-alkylene.

The patent application relates to a process for preparing polyoxymethylene by polymerization of a reaction mixture (R.sub.G) which comprises at least one formaldehyde source and at least one initiator mixture (I.sub.G), wherein the initiator mixture (I.sub.G) comprises at least one polymerization initiator and at least one solvent of the general formula (I)
R.sup.1—O—[—R.sup.3—O—].sub.m—R.sup.2  (I), where m is 1, 2, 3 or 4; R.sup.1 and R.sup.2 are each, independently of one another, C.sub.3-C.sub.6-alkyl; R.sup.3 is C.sub.1-C.sub.5-alkylene.

A process for producing polyoxymethylene polymers comprises the reaction of aqueous formaldehyde solution with an aqueous solution of a base, wherein A) a starter solution comprising formaldehyde is initially charged and B) an aqueous formaldehyde solution and a base are added to the starter solution to obtain a reaction mixture. The starter solution in step A) has a temperature of ≥40° C. to ≤46° C. and the additions of the solutions in step B) are performed at a temperature of the reaction mixture of ≥40° C. to ≤46° C. The base is an alkali metal hydroxide and/or an alkaline earth metal hydroxide and the molar ratio of formaldehyde to base is ≥55:1 to ≤90:1 based on the total amounts of formaldehyde and base employed in the process. The base in step B) is added in aqueous solution.

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.

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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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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