| 摘要 |
1,166,584. Radiation absorbent cellulose ester sheets. FARBENFABRIKEN BAYER A.G. 29 April, 1968 [29 April, 1967], No. 20118/68. Heading C3F. A transparent sheet suitable for the production of welders' screens or goggles comprises an organic cellulose ester, from 0À05-1% by wt. of a U.V. radiation absorber, from 0À01-1% of finely divided carbon black of particle size average less than 120 A and, optionally, from 0À01-0À3% of a dye soluble in the cellulose ester. By organic cellulose ester is meant a cellulose acetate having at least 55% by wt. combined acetic acid and containing not more than 20% of plasticizer; or a cellulose propionate and/or acetate butyrate containing not more than 10% of plasticizer. The ester must also have a Vicat heat distortion (defined in DIN 53 460) of at least 104‹ C. The radiation absorber may be based on benzotriazole, benzophenone or acrylonitrile. Phthalic and/or adipic ester plasticizers are specified. As dye, a proprietary phthalocyanine blue or green is specified. |
