| 摘要 |
1301058 Polyvinyl alcohol binder compositions SANDOZ Ltd 19 April 1971 [16 March 1970] 24242/71 Heading C3P [Also in Division D1] Binder compositions comprise (a) a polyvinyl alcohol, (b) a reactive cyclic methylol compound, aldehyde or compound yielding formaldehyde, (c) a metal or ammonium salt of a strong mineral acid and (d) a binder, preferably the ratio of (a) and (b) is 4 : 1 to 1 : 1. Ingredient (b) may be a cyclic methylol urea compound or a methylol-melamine compound or formaldehyde, acetaldehyde, trioxan, glyoxal, glutaraldehyde ingredient (c) preferably being magnesium, ammonium or zinc salts of strong mineral acids. The binder (d) may be a polymer or copolymer of an acrylic ester and/or acrylonitrile, butadiene, styrene, vinyl acetate, acrylic or methacrylic acid alkyl ester. The polyvinylalcohol may be partially esterified by acetate groups, be of M.W. 10,000 to 50,000 and is used as an aqueous solution. Examples 1, 20 and 29 exemplify the binder compositions. |
