A process for the production of carboxylated latexes by the selective monomer addition and polymerization
申请人:THE GOODYEAR TIRE & RUBBER COMPANY
公开号:EP0538722A1
公开(公告)日:1993-04-28
The present invention relates to a free radical emulsion polymerization process. The latex is prepared by polymerizing (a) at least one conjugated diene, (b) at least one non-carboxylic vinyl aromatic or aliphatic comonomer selected from the group consisting of styrene, α-methyl styrene, p-methyl styrene, vinyl toluene, acrylonitrile, methacrylonitrile, vinylidene chloride, ethyl acrylate, butyl acrylate, vinyl pyridine, methylmethacrylate, hexylacrylate, 2-ethyl hexyl acrylate or mixtures thereof, and (c) at least one ethylenically unsaturated carboxylic acid monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid, 3-carboxyethylacrylate, itaconic acid or mixtures thereof. The process of the present invention is characterized by (a) initially polymerizing the non-carboxylic comonomer in the presence of the unsaturated carboxylic acid and in the absence of any conjugated diene to a conversion of 3 to 12 percent to form a partially polymerized latex; and thereafter (b) copolymerizing the conjugated diene with the unreacted non-carboxylic comonomer in the partially polymerized latex. The present process mitigates the formation of codimers of the conjugated diene and non-carboxylic comonomer. The present process also provides a latex having unique film forming characteristics and polymer morphology leading to unique film stiffness and stress-strain relationship.
本发明涉及一种自由基乳液聚合工艺。胶乳是通过聚合 (a) 至少一种共轭二烯,(b) 至少一种非羧基
乙烯基芳香族或脂肪族共聚单体而制备的,该共聚单体选自
苯乙烯、α-
甲基苯乙烯、对
甲基苯乙烯、
乙烯基甲苯、
丙烯腈、
甲基丙烯腈、亚
乙烯基氯、
丙烯酸乙酯、
丙烯酸丁酯、
乙烯基吡啶、
甲基丙烯酸甲酯、
丙烯酸己酯、
丙烯酸 2-乙基己酯或它们的混合物、(c) 至少一种
乙烯基不饱和
羧酸单体,选自
丙烯酸、
甲基丙烯酸、
马来酸、
富马酸、3-羧乙基
丙烯酸酯、
衣康酸或其混合物组成的组。本发明工艺的特点是:(a) 非
羧酸共聚单体在有不饱和
羧酸和没有任何共轭二烯的情况下进行初始聚合,转化率为 3-12%,形成部分聚合胶乳;然后(b) 共轭二烯与未反应的非
羧酸共聚单体在部分聚合胶乳中进行共聚。本工艺减少了共轭二烯和非
羧酸共聚单体的形成。本工艺还提供了一种具有独特成膜特性和聚合物形态的胶乳,从而形成独特的薄膜刚度和应力应变关系。