Patent ID: 6974849

Claim:
A molding composition exhibiting bleach resistance comprising a polyoxymethylene matrix polymer, wherein the polyoxymethylene is selected from the group consisting of oxymethylene copolymers comprising about 90 to about 99.9 percent oxymethylene repeat units interspersed with repeat units derived from ethylene oxide or 1,3 dioxolane, wherein said molding composition further comprises from about 0.5 to about 10 weight percent of a bleach stabilizer selected from alkali metal or alkaline earth element carbonates or phosphates and mixtures thereof dispersed in the matrix resin and a bleach co-stabilizer selected from the group consisting of: (a) a poly(alkoxy) stabilizer; (b) a zinc oxide stabilizer; (c) a color stabilizer consisting of a mixture of calcium citrate and calcium propionate, wherein the calcium citrate is the predominant component of the color stabilizer mixture, and wherein said calcium citrate is in an amount of about 0.05-0.1 weight % ; or (d) mixtures of two or more of (a), (b) and (c); and wherein the composition exhibits a bleach resistance index of at least 2.0.