| 摘要 |
1,229,634. Treating cellulose diacetate. TEIJIN Ltd. 27 Nov., 1968 [28 Nov., 1967], No. 56381/68. Heading C3A. Acetone-soluble cellulose diacetate is heated, e.g. at 85-100‹ C. in a dilute acid until its " refinement parameter at the stability of 0À08% " is no higher than 80, is washed, dissolved in an acetonic solvent and spun. The " refined parameter " is a measure of alkalinity as p.p.m. Ca<SP>++</SP> and the " stability " a measure of extractable CH 3 OOH; the method of measuring both is described. The acid may be HCl, HNO 3 , H 3 PO 4 or CH 3 COOH. For mineral acids a concentration of 0À05-0À005% may be used; for fatty acids, 10-0À5%. An additional or simultaneous bleaching treatment with, e.g. NaOCl, KMnO 4 , or H 2 O 2 , may be effected. The filaments produced are resistant to hydrothermal delustering; certain of these are claimed per se. |
