| 摘要 |
PURPOSE: To enable the removal of an unmodified epoxy resin without using concentrated sulfuric acid, chromic acid, etc., by using an alcohol solvent and water to adjust the composition of an etchant for a specific cured epoxy resin. CONSTITUTION: A bifunctional epoxy resin is mixed with a halogenated dihydric phenol such as a halogenated (alkylated) dihydric phenol in such a ratio that the proportion of the epoxy groups to the phenolic hydroxyl groups is 1/0.9 to 1/1.1. This mixture is thermally polymerized in an amide or ketone solvent having a b.p. of 130 deg.C or higher in the presence of an etherification catalyst to obtain an epoxy resin (A) having a mol.wt. of 100,000 or higher and capable of forming a film. The ingredient (A) is compounded with a crosslinking agent (B) consisting of a masked isocyanate and a polyfunctional epoxy resin, an amide solvent (C), an alcohol solvent solution (D) of 0.5-40wt.% alkali metal compound and water (E). The amounts of the ingredients (B), (C), (D), and (E) are 20-100wt.%, 30-89%, 1-60wt.%, and 10-30wt.%, respectively, based on the ingredient (A). |
