US 7,528,212 B2
Ionizing radiation stable thermoplastic composition, method of making, and articles formed therefrom
Brian Mullen, Mt. Vernon, Ind. (US)
Assigned to SABIC Innovative Plastics IP B.V., Bergen op Zoom (Netherlands)
Filed on Nov. 18, 2005, as Appl. No. 11/282,377.
Prior Publication US 2007/0117957 A1, May 24, 2007
Int. Cl. C08G 63/00 (2006.01)
U.S. Cl. 528—190  [250/472.1; 250/474.1; 264/176.1; 264/219; 428/411.1; 428/412] 26 Claims
 
1. A thermoplastic composition comprising:
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)—Ar1
wherein each Ar1 is independently an aryl group, -(-L-)m- is a polycarbonate linking group with m units of linking unit L, wherein L consists essentially of carbonate units wherein m is at least one, or a combination of carbonate units with poly(arylene ether) units, soft block units, or a combination comprising at least one of these, wherein m is 2 to 500 and at least one L is a carbonate unit;
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 that is not aryl carboxylate end-capped, 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.