| 摘要 |
<p>Stabilising a multi-layered, thermoplastic article, prepd. by coextrusion, comprises co-extruding a thermoplastic resin(s) to give a multi-layered thermoplastic article having an outer UV absorbing thermoplastic layer, 0.1-10 mil thick, contg. 0.1-20 wt.% bis-benzophenone UV absorber of formula (I) (where X is 1-16C alkylene, o-, m- or p-xylylene or an oxa-alkanediyl of formula -CH2CH2(OCH2CH2)n-, -CH2CH(CH3)(OCH2CH(CH3))n- or -CH2CH2CH2CH2(OCH2CH2CH2CH2)n- (where n = 1-4); Y is H or 1-18C alkyl; and Z is H, Cl or 1-18C alkyl or alkoxy). The UV absorbing layer contains 2-15, pref. 5-10 wt.% (I). The thermoplastic resin, which in the article and the coating layer may be the same or different resin, is selected from aromatic polycarbonates, polyesters, polyester carbonates, polyphenylene oxide, PVC, polypropylene, polyethylene, poly(meth)acrylates and copolymers and blends such as styrene and acrylonitrile on polybutadiene and styrene with maleic anhydride. The pref. resin is a polycarbonate based on a dihydric phenol selected from bisphenol A, 2,4-bis(4-hydroxyphenyl)- 2-methyl-butane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(3-chloro- 4-hydroxyphenyl) propane, 4,4'-sulphonyldiphenol and 1,1-bis (4-hydroxyphenyl)- 3,3,5-trimethylcyclohexane. The pref. resin for both article and coating layer is a polycarbonate based on bisphenol A.</p> |
