申请人:E.I. DU PONT DE NEMOURS AND COMPANY
公开号:EP0092624A2
公开(公告)日:1983-11-02
A thermosetting coating composition with enhanced flexibility and impact strength and excellent weatherability adapted for use as an automotive topcoat which upon curing forms a hard, glossy, durable coating. The coating composition comprises:-
(A) a modified hydroxy acrylic copolymer which is the stepwise reaction product of:-
(i) a copolymer bearing pendant hydroxyl groups and having a number average molecular (Mn) of between about 1000-5000,
(ii) a dicarboxylic acid anhydride comprising at least about 50 percent by weight of an alkyl hexahydrophthalic anhydride, and
(iii) a monoepoxide functional monomer comprising at least about 90 percent by weight of a C2-C10 monoepoxide functional monomer;
(B) an amine-aldehyde or polyisocyanate crosslinking agent;
(C) optionally a hydroxy functional additive, and
(D) solvent.
The anhydride is reacted in an amount sufficient to esterify at least about 30 percent of the pendant hydroxyl groups of copolymer (i) thereby generating carboxyl functionality, substantially all of which is thereafter reacted with the monoepoxide functional monomer. The crosslinking agent is included in the composition in an amount sufficient to provide at least about 0.5 equivalent of crosslinking functionality per equivalent of hydroxy functionality included in the composition either as a hydroxyl group of the modified hydroxy acrylic copolymer or as a hydroxyl group of the optional hydroxy-functional additive.
(ii) dicarboxylic acid anhydride comprising at least 50 percent by weight of an alkyl hexahydrophthalic anhydride, wherein (i) and (ii) are reacted in an amount sufficient to esterify from 30 to 100 percent of the hydroxyl groups of the copolymer, thereby generating pendant carboxyl groups; and
(iii) a monoepoxide functional monomer comprising at least 90 percent by weight C - C10 monoepoxide functional monomers, wherein the monomer is reacted with the pendant carboxyl groups of the polymer reaction product of (i) and (ii) so as to provide at least 1.0 equivalent of epoxide groups per equivalent of the pendant carboxyl groups generate pendant hydroxyl groups;
(B) an amine-aldehyde or polyisocyanate crosslinking a gent; (C) 0-50 weight percent based on the total weight of (A), (B), (C) and (L) of a hydroxy functional additive having a number average molecular weight (Ln) of from 150 to 6000, preferably 500-2500; and (D) solvent.
The amine-aldehyde crosslinking agent is included in the composition in an amount sufficient to provide at least 0.60, preferably from 0.75 to 3.75, equivalents of nitrogen crosslinking functionality for each equivalent of hydroxyl functionality included in the composition either as a hydroxyl group on the modified hydroxy acrylic copolymer or as a hydroxyl group on the hydroxy functional additive.
The polyisocyanate crosslinking agent is included in an amount sufficient to provide 0.5 to 1.6 reactive isocyanate groups for each equivalent of hydroxy functionality included in the composition as an hydroxyl group on either the said copolymer or said additive.
The composition preferably contains at least 60% by weight and preferably at least 70% by weight of non-volatile solids. In addition, the coating composition of this invention may include additives such as catalysts, antioxidants, U.V. absorbers, flow control or wetting agents, antistatic agents, pigments, plasticizers,
一种热固性涂料组合物,具有增强的柔韧性和抗冲击强度以及优异的耐候性,适合用作汽车面漆,固化后可形成坚硬、光亮、耐用的涂层。该涂料组合物包括
(A) 改性羟基丙烯酸共聚物,它是下列物质的逐步反应产物
(i) 含有悬垂羟基且平均分子数(Mn)在 1000-5000 之间的共聚物、
(ii) 二羧酸酐,包括至少约 50%(按重量计)的烷基六氢邻苯二甲酸酐, 以及
(iii) 单环氧化物官能团单体,包括至少约 90%(按重量计)的 C2-C10 单环氧化物官能团单体;
(B) 胺醛或多异氰酸酯交联剂;
(C) 可选的羟基官能添加剂,以及
(D) 溶剂。
酸酐的反应量足以酯化共聚物 (i) 中至少约 30% 的悬垂羟基,从而产生羧基官能团,此后,基本上所有的羧基官能团都与单环氧官能团单体反应。交联剂加入组合物中的量足以为组合物中每一当量羟基官能团提供至少约 0.5 个当量的交联官能团,可以是改性羟基丙烯酸共聚物的羟基,也可以是任选羟基官能团添加剂的羟基。
(ii) 二羧酸酐,包括至少 50%(重量)的烷基六氢邻苯二甲酸酐,其中(i)和(ii) 的反应量足以酯化共聚物 30%至 100%的羟基,从而生成悬垂羧基;以及
(iii) 单环氧化物官能团单体,包括至少 90%(重量百分比)的 C - C10 单环氧化物官能团单体,其中该单体与(i)和(ii)的聚合物反应产物的垂羧基反应,以提供至少 1.0 个当量的环氧化物基团,每个当量的垂羧基生成垂羟基;
(B) 一种胺-醛或多异氰酸酯交联剂; (C) 以(A)、(B)、(C)和(L)的总重量为基准,0-50 重量百分数的羟基官能团添加剂,其平均分子量 (Ln) 为 150-6000,最好为 500-2500;以及 (D) 溶剂。
胺-醛交联剂在组合物中的加入量足以为组合物中每一当量的羟基官能团提供至少 0.60(优选 0.75 至 3.75)当量的氮交联官能团,这些羟基官能团可以是改性羟基丙烯酸共聚物上的羟基,也可以是羟基官能添加剂上的羟基。
多异氰酸酯交联剂的加入量足以为组合物中每一当量的羟基官能团提供 0.5 至 1.6 个活性异氰酸酯基团,作为所述共聚物或所述添加剂上的羟基基团。
按重量计,该组合物最好含有至少 60%,最好至少 70%的非挥发性固体。此外,本发明的涂料组合物还可包括添加剂,如催化剂、抗氧化剂、紫外线吸收剂、流动控制剂或润湿剂、抗静电剂、颜料、增塑剂、