This invention relates to the synthesis of a latex which can be formulated into coatings having improved flexibility and good water resistance. Coatings of this type are particularly useful in roof coating applications because they offer excellent flexibility, excellent ultra-violet light resistance, and good water resistance. The subject invention more specifically discloses a process for producing a neutralized latex that is useful in the manufacture of water reducible coatings which comprises:
(1) free radical aqueous emulsion polymerizing, at a pH of less than about 3.5, a monomer mixture which comprises, based on 100 weight percent monomers: (a) from about 30 to about 70 weight percent vinyl aromatic monomers, (b) from about 25 to about 65 weight percent of at least one alkyl acrylate monomer, (c) from about 1 to about 5 weight percent of acrylic acid, and (d) about 0.4 to about 3 weight percent methacrylic acid; in the presence of about 0.2 to 0.4 phm at least one sulfonate surfactant and in the presence of about 4 to 8 phm of at least one nonionic surface active agent having a hydrophile-lipophile balance number which is within the range of about 12 to about 20 to produce a latex; and
(2) neutralizing the latex with ammonia to a pH which is within the range of about 7 to about 10.5 to produce the neutralized latex.
本发明涉及一种胶乳的合成,这种胶乳可以配制成具有更好柔韧性和良好耐
水性的涂料。这种类型的涂料尤其适用于屋顶涂料应用,因为它们具有优异的柔韧性、优异的抗紫外线能力和良好的耐
水性。本发明更具体地公开了一种生产中和胶乳的工艺,这种胶乳可用于制造可还原防
水涂料,其工艺包括: 1:
(1) 在 pH 值小于约 3.5 的条件下,对单体混合物进行自由基
水乳液聚合,该单体混合物以 100 重量百分比的单体为基础包括:(a) 约 30 至约 70 重量百分比的
乙烯基芳香族单体,(b) 约 25 至约 65 重量百分比的至少一种
丙烯酸烷基酯单体,(c) 约 1 至约 5 重量百分比的
丙烯酸,以及 (d) 约 0.4 至约 3 重量百分比的
甲基丙烯酸;在约 0.2 至 0.4 phm 的至少一种
磺酸盐表面活性剂和约 4 至 8 phm 的至少一种非离子表面活性剂的存在下,产生胶乳,该表面活性剂的亲
水-亲脂平衡数在约 12 至约 20 的范围内;以及
(2) 用
氨水将胶乳中和至 pH 值在约 7 至约 10.5 范围内,生成中和胶乳。