GB1098785A - Improvements in or relating to stabilization of polyacetal resins - Google Patents

Abstract

Compositions comprise (1) a polymer of formaldehyde or trioxan having a molecular weight of 10,000 to 200,000 and a melting-point above 150 DEG C., (2) 0.1 to 30% of a phenyl alkanoic acid ester of the formula <FORM:1098785/C3/1> where n is 1 to 5, R is an alkyl group having 12 to 22 carbon atoms, and R1 is an alkyl group having 3 to 8 carbon atoms and branched at the alpha carbon atom, and optionally (3) 0.1 to 50% of a superpolyamide, cyanoguanidine, a substituted cyanoguanidine, polyaminotriazole, amino-substituted s-triazine, imidazoline or a mixture thereof, and optionally (4) 0.001-0.8% of a diester of a thiodialkanoic acid of the formula <FORM:1098785/C3/2> where R1 is an alkyl group having 8 to 20 carbon atoms, an hydroxyalkyl group having 1 to 4 carbon atoms, cycloalkyl group, or a polyoxyalkyl group, and x and y are 1 to 3. The use of the following stabilizers is exemplfied (2) dodecyl-, octadecyl-, and eicosyl-(3,5-di-t.-butyl-4-hydroxyphenyl propionates, and octadecyl-(3,5 - di - t. - butyl - 4 - hydroxyphenyl) butyrate, (3) terpolymer of polycaprolactam, polyhexamethylene adipamide, and polyhexamethylene sebacamide, and dicyandiamide, and (4) dilauryl 3,31-thiodipropionate. Polymers stabilized in the examples are (1) and (2) polyoxymethylene acetylated with two or more acetate groups per molecule and (3), (4) and (5) a trioxan-dioxolan copolymer having an inherent viscosity of 1.8 in p-chlorophenol.