Abstract: Polyoxymethylene molding materials having improved heat stability and consisting of(A) one or more polyoxymethylene homopolymers and/or copolymers and(B) one or more antioxidants having a sterically hindered phenolic structure,(C) with or without additives, contain(D) as an additive, one or more alkaline earth metal silicates and/or alkaline earth metal glycerophosphates, advantageously in an amount of from 0.002 to 2.0% by weight, based on the weight of component (A),for improving the heat stability, reducing the tendency to discoloration and minimizing the free formaldehyde content.To prepare the novel polyoxymethylene molding materials, the components are advantageously melted in an extruder at from 150.degree. to 260.degree. C.The polyoxymethylene molding materials are useful for the production of films or, preferably, moldings, which are used, for example, in the automotive, electrical appliances and electronics industries.

Abstract: Molding materials of(A) one or more polyoxymethylene homopolymers and/or copolymers and(B) one or more thermoplastic polyurethane elastomers,(C) with or without additives, contain, as an additive,(D) one or more alkaline earth metal silicates, advantageously in an amount of from 0.005 to 2% by weight, based on the weight of the components (A) and (B), for improving the heat stability, reducing the tendency to discoloration and minimizing the free formaldehyde content.To prepare the molding materials, the components (A), (B), (D) and, if required (C) are advantageously melted together in an extruder at from 150.degree. to 260.degree. C.The molding materials are useful for the production of films or moldings, which are used, for example, in the automotive, electrical appliances and electronics industries.

Abstract: Thermoplastic polyoxymethylene molding materials having high abrasion resistance contain(A) from 4 to 94.7 parts by weight of polyoxymethylene,(B) from 5 to 50 parts by weight of wollastonite,(C) from 0.2 to 5 parts by weight of N-hydroxymethylmelamines in which some or all of the hydroxymethyl groups are etherified with alkanols,(D) from 0.1 to 5 parts by weight of a silicone oil having a degree of polycondensation n of from 10 to 5,000 and/or(E) from 0.1 to 10 parts by weight of polyethylene and/or copolymers of ethylene and .alpha.-olefins having a molecular weight of from 100,000 to 1,000,000,the number of parts by weight of components A, B, C, D and E summing to 100, with or without(F) effective amounts of additives.

Abstract: Impact-resistant polyoxymethylene molding materials containing(A) from 30 to 95% by weight of one or more polyoxymethylenes and(B) from 5 to 70% by weight of one or more elastomeric graft polymers which are prepared by emulsion polymerization, are dispersed in component A, have a mean particle diameter of from 0.08 to 2 .mu.m and are composed of1. from 60 to 90% by weight of a grafting base of crosslinked polybutadiene in which not more than 30% by weight of the butadiene may be replaced with isoprene, 2,3-dimethylbutadiene, styrene, p-methylstyrene, .alpha.-methylstyrene and/or (meth)acrylonitrile, and2. from 10 to 40% by weight of one or more grafted shells consisting of polymers of styrene and/or methyl methacrylate, in which not more than 15% by weight of the said monomers 2 may be replaced with acrylonitrile or a C.sub.1 -C.sub.8 -alkyl acrylate,the percentages A and B and the percentages 1 and 2 summing to 100, with or without(C) effective amounts of assistants,and a process for their preparation.

Abstract: Polyacetal molding materials which contain, as a stabilizer, from 0.1 to 10% by weight of a melamine resin, the latter being a melamine-formaldehyde condensate, having a mean degree of polymerization of from 1.2 to 6.0 and a melamine:formaldehyde ratio of from 1:2 to 1:5.5, which has been partially etherified with a C.sub.1 -C.sub.4 -alkanol so that the ratio melamine:ether radicals is from 1:1.5 to 1:5.0 and the ratio melamine:free methylol groups is from 1:0.5 to 1:3. The molding materials can be converted to moldings which can be used industrially at elevated ambient temperatures.

Abstract: Method of removing odorous formaldehyde from stabilized shaped polyoxymethylenes in which an inert gas is caused to flow over stabilized and shaped solid polyoxymethylenes at elevated temperatures not high enough to cause sticking or fusion of the polyoxymethylene, until substantially all of the volatile formaldehyde has been removed.