Vinyl alcohol copolymers for use in aqueous dispersions and melt extruded articles
申请人:Vicari Richard
公开号:US20050065272A1
公开(公告)日:2005-03-24
In a method of preparing an aqueous dispersion selected from drilling fluids, hydraulic cement compositions, mineral pigment containing coatings, and papermaking furnishes or in a method of preparing a melt extrudate, the improvement comprising: a) producing a copolymer of vinyl alcohol (VOH) and 2-acrylamido-2-methyl propane sulfonic acid or a salt of such acid (AMPS) by steps including continuously feeding with agitation, vinyl acetate (VAM) and AMPS as comonomers, a free radical yielding polymerization initiator, and a solvent for said comonomers, initiator, and copolymer resulting from the copolymerization of said comonomers, maintaining the resulting reaction mass in said first reaction zone under polymerization conditions for a residence time sufficient for a major proportion of AMPS fed to said first reaction zone to polymerize, continuously feeding reaction mass from said first reaction zone with an additional supply of AMPS to a second reaction zone, maintaining the reaction mass in the second reaction zone for a residence time sufficient to polymerize a major proportion of the AMPS added to the second reaction zone, continuously withdrawing reaction mass from the second reaction zone, separating copolymer of VAM and AMPS from the latter reaction mass, and saponifying by hydrolysis and/or alcoholysis a major proportion of the acetate groups in said copolymer to form a copolymer of VOH and AMPS; and b) incorporating the saponified copolymer into the aqueous dispersion or melt extrudate.
在一种制备选自钻井液、液压水泥组合物、含矿物颜料的涂料和造纸原料的水性分散体的方法中,或在一种制备熔融挤出物的方法中,改进措施包括a) 生产乙烯醇(VOH)和 2-丙烯酰胺基-2-甲基丙烷磺酸或这种酸的盐 (AMPS)的共聚物,步骤包括在搅拌下连续喂入作为共聚单体的醋酸乙烯 酯(VAM)和 AMPS、产生自由基的聚合引发剂和上述共聚单体的溶剂、在聚合条件下,将第一反应区中的反应物保持足够的停留时间,使进入第一反应区的大部分 AMPS 发生聚合、将反应物从第一反应区持续加入额外供应的 AMPS 至第二反应区,将反应物在第二反应区保持足够的停留时间,以使加入第二反应区的大部分 AMPS 发生聚合反应,从第二反应区持续抽出反应物,从后一反应物中分离出 VAM 和 AMPS 的共聚物,并通过水解和/或醇解将所述共聚物中大部分醋酸基团皂化,以形成 VOH 和 AMPS 的共聚物;b) 将皂化共聚物加入水性分散体或熔融挤出物中。