Preparing laminated thermoplastics stabilized with bisbenzophenones
First Claim
1. A process for stabilizing a multi-layered, thermoplastic article, prepared by coextrusion, which process comprises coextruding a thermoplastic resin or mixture of thermoplastic resins to give a multi-layered thermoplastic article having an outer UV absorbing thermoplastic layer 0.1 to 10 mil (0.00254 to 0.254 mm) thick, which said outer UV absorbing layer contains 0.1 to 20% by weight of a bisbenzophenone UV absorber of the formula ##STR4## wherein X is a straight or branched chain alkylene of 1 to 16 carbon atoms, o-, m- or p-xylylene or an oxa-alkanediyl of the formula --CH2 CH2 [OCH2 CH2 ]n --, --CH2 CH(CH3)[OCH2 CH(CH3)]n -- or --CH2 CH2 CH2 CH2 [OCH2 CH2 CH2 CH2 ]n -- where n is 1-4,Y is hydrogen, straight or branched chain alkyl of 1-18 carbon atoms, andZ is hydrogen, chloro, straight or branched chain alkyl of 1 to 18 carbon atoms or alkoxy of 1 to 18 carbon atoms.
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Accused Products
Abstract
Thermoplastic articles, preferably of polycarbonate, are advantageously stabilized by selected bisbenzophenone UV absorbers concentrated in the outer surface or coating layers of the article prepared by coextrusion techniques.
33 Citations
12 Claims
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1. A process for stabilizing a multi-layered, thermoplastic article, prepared by coextrusion, which process comprises coextruding a thermoplastic resin or mixture of thermoplastic resins to give a multi-layered thermoplastic article having an outer UV absorbing thermoplastic layer 0.1 to 10 mil (0.00254 to 0.254 mm) thick, which said outer UV absorbing layer contains 0.1 to 20% by weight of a bisbenzophenone UV absorber of the formula ##STR4## wherein X is a straight or branched chain alkylene of 1 to 16 carbon atoms, o-, m- or p-xylylene or an oxa-alkanediyl of the formula --CH2 CH2 [OCH2 CH2 ]n --, --CH2 CH(CH3)[OCH2 CH(CH3)]n -- or --CH2 CH2 CH2 CH2 [OCH2 CH2 CH2 CH2 ]n -- where n is 1-4,
Y is hydrogen, straight or branched chain alkyl of 1-18 carbon atoms, and Z is hydrogen, chloro, straight or branched chain alkyl of 1 to 18 carbon atoms or alkoxy of 1 to 18 carbon atoms.
Specification