The current invention relates to a process for preparing an aqueous binder composition free of organic solvent, the process comprising at least the following steps: A) preparing a hydrophilic vinyl polymer (Polymer A) by polymerisation of a monomer composition A that contains: Ai) at least one carboxylic acid functional olefinically unsaturated monomer; and Aii) at least one olefinically unsaturated monomer different than Ai); and Aiii) optionally at least one wet adhesion promoting olefinically unsaturated monomer different than Ai and Aii); where Polymer A has an acid value (AV) from 32 to 98 mg KOH/g of solid Polymer A; B) preparing a hydrophobic vinyl polymer (Polymer B) by emulsion polymerization of a monomer composition B in the presence of Polymer A where the monomer composition B contains: Bi) at least one olefinically unsaturated monomer; Bii) optionally carboxylic acid functional olefinically unsaturated monomer different than Bi); and Biii) optionally wet adhesion promoting olefinically unsaturated monomer different than Bi); where Polymer B has an acid value (AV) of no more than 23.4 mg KOH/g of solid polymer B, wherein at least a part of the carboxylic acid groups that are present in Polymer A and Polymer B are neutralized during or following the steps A and/or B to form a (partially) neutralized polymer emulsion; where the weight average molecular weight (Mw) of Polymer A is lower than the weight average molecular weight (Mw) of polymer B; and wherein the process is further characterized by the presence of a further step C) reacting at least 10 mol % of the carboxylic acid and/or carboxylate salt groups of the (partially) neutralized polymer emulsion with an iminating agent to produce an iminated polymer C; wherein the total amount of surfactant applied in steps A, B and C is at most 0.5 wt. %, based on the total weight of monomers charged for the preparation of polymer A and polymer B.
本发明涉及一种制备不含有机溶剂的
水性粘结剂组合物的工艺,该工艺至少包括以下步骤:A) 通过单体组合物 A 的聚合制备亲
水性
乙烯基聚合物(聚合物 A),单体组合物 A 含有:Ai) 至少一种
羧酸官能团烯烃不饱和单体;和 Aii) 至少一种不同于 Ai) 的烯烃不饱和单体;和 Aiii) 可选的至少一种不同于 Ai 和 Aii) 的湿粘附促进烯烃不饱和单体;其中聚合物 A 的酸值(AV)为 32 至 98 毫克 KOH/克固体聚合物 A; B) 在聚合物 A 存在的情况下,通过单体组合物 B 的乳液聚合制备疏
水性
乙烯基聚合物 (聚合物 B),其中单体组合物 B 包含:Bi)至少一种烯烃不饱和单体;Bii)不同于 Bi)的任选
羧酸官能烯烃不饱和单体;以及 Biii)不同于 Bi)的任选湿粘附促进烯烃不饱和单体;其中聚合物 B 的酸值(AV)不超过 23.4 mg KOH/g 的固体聚合物 B,其中至少一部分存在于聚合物 A 和聚合物 B 中的
羧酸基团在步骤 A 和/或 B 期间或之后被中和,以形成(部分)中和聚合物乳液;其中聚合物 A 的重量平均分子量(Mw)低于聚合物 B 的重量平均分子量(Mw);其中该工艺的进一步特征是存在进一步的步骤 C)将(部分)中和聚合物乳液中至少 10 mol % 的
羧酸和/或
羧酸盐基团与
亚胺化剂反应,生成
亚胺化聚合物 C;其中在步骤 A、B 和 C 中应用的表面活性剂总量最多为 0.5 wt. %,以制备聚合物 A 和聚合物 B 所需的单体总重量为基准。