| 摘要 |
<p>1,229,074. Polycarbonate mouldings. FARBENFABRIKEN BAYER A.G. 1 Oct., 1969 [1 Oct., 1968], No. 48280/69. Addition to 1,171,888. Heading C3R. A thermoplastic polycarbonate moulding derived from one or more dihydric phenols and containing from 3-30 gm./sq. m. of at least one U.V.- absorber in an outer layer to a depth of 5-30 Á and having a sealed surface is produced by applying from 150-300 c.c./sq. m. of a solution containing the U.V. absorber and evaporating the solvent. The solution contains, by weight 2À5-10% U.V. absorber, and a solvent consisting of 80-20% 1,2 - dichloroethane or 1,2 - dichloropropane and 20-80% 1,1,2 - trifluoro 1,2,2 - trichloroethane or 1,1,2,2 - tetrachloro - difluoroethane. The solution may be applied by spraying or by dipping the moulding, at room temperature for 5-50 sees. into the solution and allowing the excess to drip off before evaporating the solvent. In the examples 2 - (2<SP>1</SP> - hydroxy - 3<SP>1</SP>,5<SP>1</SP> - di - tert - butylphenyl)- benzotriazole, 2 - (21 - hydroxy - 51 - methylphenyl) - benzotriazole, 2,2<SP>1</SP>- dihydroxy - 4- methoxy - benzophenone and 2 - (21 - hydroxy- 3<SP>1</SP>,5<SP>1</SP> - diamyl) - benzotriazole are used as U.V. absorbers.</p> |
