POLYOXYMETHYLENE MOLDING MATERIALS WITH IMPROVED THERMOSTABILITY, NUCLEATION TENDENCY AND DISCOLORATION RESISTANCE

摘要

The invention relates to polyoxymethylene molding materials which contain (i) at least one polyoxymethylene homo- and/or copolymer, (ii) at least one conventional adjuvant and (iii) at least one polymeric plastic material as additive which at the same time promotes nucleation and improves thermostability. Said molding materials are characterized in that (iii) is a copolymer which is obtained by polymerization in substance or in solution of a mixture of A1) 0.1-100 parts of one or more cross-linking agents with at least two polymerizable carbon-carbon double bonds, A2) 0.1-99.9 parts of one or more acrylates and/or methacrylates, B) 0.1-99.9 parts of one or more acrylamides and/or methacrylamides and/or dialkylaminoalkylacrylates and/or dialkylaminoalkylmethacrylates, C) based on 100 parts A) + B) 0.2 to 10 parts molecular weight controller and D) based on 100 parts A) + B) up to 5 parts radicalic polymerization initiators. The molding materials are further characterized in that (iii) is contained in the molding material in an amount of 0.01 to 2 parts based on the sum of (i) + (ii), whereby all amounts relate to parts by weight (wt/wt) and A1), A2) and B) together must give 100 parts. The use of cross-linked polymers in POM molding materials results in advantages with respect to the thermal stability, resistance to discoloration and at the same time to the nucleation tendency of POM molded materials.