A carboxyl resin according to the present invention is obtained by a process including following steps: epoxy groups on a resin (a) having two or more epoxy groups in one molecule is made to react with 0.3-0.85 mol of a monocarboxylic acid (b) per one epoxy-group equivalent weight to obtain a reaction product (c); the epoxy group or groups on the reaction product (c) are made to react with 0.15-0.95 mol of a polybasic acid (d) per one epoxy-group equivalent weight to obtain a reaction product (e); and the epoxy group or groups on the reaction product (e) are further made to react with 1.0-5.0 mol of a monocarboxylic acid (f) per one epoxy-group equivalent weight. The carboxyl resin thus obtained has an acid value within a range from 20 to 200 mgKOH/g and is soluble in an organic solvent.
根据本发明,通过以下步骤获得一种羧基
树脂:将具有一个分子中两个或更多环氧基团的
树脂(a)上的环氧基团与0.3-0.85摩尔的单
羧酸(b)反应,以获得反应产物(c);将反应产物(c)上的环氧基团与0.15-0.95摩尔的多元酸(d)反应,以获得反应产物(e);将反应产物(e)上的环氧基团与1.0-5.0摩尔的单
羧酸(f)进一步反应。因此获得的羧基
树脂酸值在20至200mgKOH/g范围内,并且可溶于有机溶剂。