Disclosed herein are water-based protective composition for coating films. The compositions contain (a) a water-based dispersion of copolymer particles having a number average molecular weight of from 2,000 to 20,000 and a glass transition point of from -10°C to +40°C and obtained by emulsion-polymerizing 100 parts by weight of a monomer mixture consisting substantially of (X) 7-12 parts by weight of an α,β-monoethylenically-unsaturated carboxylic acid and (Y) 88-93 parts by weight of at least one ester selected from the group consisting of C₁₋₄-alkyl acrylates and C₁₋₄-alkyl methacrylates; as well as specific amounts of (b) an ultraviolet absorber, (c) an antioxidant, (d) a thickening agent and (e) a surface active agent. They can form barrier coats having excellent removability, weatherability, waterproofness, heat resistance and coating-film-protecting property. Their preparation processes are also disclosed.
本文公开了用于涂膜的
水基保护组合物。该组合物含有 (a) 共聚物颗粒的
水基分散液,该共聚物颗粒的平均分子量为 2,000 到 20,000 之间,
玻璃化转变点为 -10°C 到 +40°C,由 100 份(重量)单体混合物乳液聚合而成,该单体混合物主要由(X) 7-12 份(重量)α、β-单
乙烯基不饱和
羧酸和(Y)88-93 份(按重量计)至少一种选自 C₁₋₄-烷基
丙烯酸酯和 C₁₋₄-烷基
甲基丙烯酸酯的酯;以及特定量的 (b)
紫外线吸收剂、(c)
抗氧化剂、(d)
增稠剂和 (e) 表面活性剂。它们可以形成具有优异的可移除性、耐候性、防
水性、耐热性和涂膜保护特性的阻隔涂层。此外,还公开了它们的制备工艺。