申请人:THE DOW CHEMICAL COMPANY
公开号:EP0253405A2
公开(公告)日:1988-01-20
An advanced epoxy cationic resin having a charge density of from 0.2 to 0.6 milliequivalent of cationic charge per gram of resin is prepared by reacting in the presence of a suitable catalyst (A) a composition comprising (1) at least one diglycidyl ether of a polyol and (2) at least one diglycidyl ether of a dihydric phenol with (B) at least one dihydric phenol and optionally (C) a monofunctional capping agent. Components (A-1) and (A-2) are employed in quantities such that from 10 to 75 weight percent of the diglycidyl ethers contained in component (A) are contributed by component (A-1), and from 25 to 90 weight percent of such glycidyl ethers are contributed by component (A-2). Components (A) and (B) are employed in such quantities that the resultant epoxy resin has an average epoxide equivalent weight of from 350 to 10,000.
The terminal oxirane groups in thus formed advanced epoxy resin are converted to cationic groups by reacting the resin with a nucleophilic compound and adding an organic acid and water at at least one point in the reaction. Process for the preparation of these advanced epoxy cationic resins is also disclosed.
Advanced epoxy cationic resin of this invention are employed in the preparation of coating compositions suitable for electrodeposition.
一种高级环氧阳离子树脂,其电荷密度为每克树脂含 0.2 至 0.6 毫当量的阳离子电荷,其制备方法是在适当的催化剂存在下,使(A)包含(1)至少一种多元醇的二缩水甘油醚和(2)至少一种二元苯酚的二缩水甘油醚的组合物与(B)至少一种二元苯酚和任选的(C)单官能团封端剂反应。组分(A-1)和(A-2)的用量为:组分(A)所含二缩水甘油醚的 10-75%由组分(A-1)提供,而这种缩水甘油醚的 25-90%由组分(A-2)提供。组分(A)和(B)的使用量应使生成的环氧树脂的平均环氧化物当量重量为 350 至 10,000。
通过使树脂与亲核化合物反应,并在反应的至少一个阶段加入有机酸和水,从而将由此形成的高级环氧树脂中的末端环氧基团转化为阳离子基团。此外,还公开了这些高级环氧阳离子树脂的制备工艺。
本发明的高级环氧阳离子树脂可用于制备适用于电沉积的涂层组合物。