IONIZING RADIATION STABLE THERMOPLASTIC COMPOSITION, METHOD OF MAKING, AND ARTICLES FORMED THEREFROM

• Main Author: MULLEN, BRIAN
• Format: Patent
• Language: English; French; German
• Published: 30.07.2008
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

A thermoplastic composition comprises a polycarbonate that is not aryl carboxylate end-capped, and an aryl carboxylate end-capped polycarbonate of formula: Ar1-C(O)-O-(-L-)m-O-C(O)-A1 wherein each Ar1 is independently an aryl group, -(-L-)m- is a polycarbonate linking group with m units of linking unit L, and m is at least one; wherein the aryl carboxylate end-capped polycarbonate has aryl carboxylate end groups present in the thermoplastic composition in an amount of 0.01 to 500 mmol/Kg based on the combined weights of the polycarbonate that is not aryl carboxylate end-capped, and the aryl carboxylate end-capped polycarbonate, and wherein a molded article having a thickness of 3.2±0.12 millimeters and consisting of the aryl carboxylate end-capped polycarbonate, the polycarbonate, and less than or equal to 1.0 percent total weight of aliphatic diol, a mold-release agent, and an antioxidant has, after exposure to a total gamma radiation dose of 81 kGy and when measured according to ASTM D1925-70, an increase in yellowness index (dYI) of less than or equal to 24.5, when compared to the unexposed molded article. A method for preparing the aryl carboxylate end-capped polycarbonate that is not aryl carboxylate end-capped, and thermoplastic composition, an article prepared from the thermoplastic composition, are also disclosed.