Modified epoxy resin and electrodeposition coating material

Abstract

The present invention provides an epoxy resin that has excellent curability, when a low-activity catalyst is used or when used at low temperatures, that has excellent storage stability, and that yields a coating material having excellent coating film finish properties and corrosion resistance. The present invention further addresses an object of providing an amine-modified epoxy resin produced by reacting the epoxy resin with an amine compound, as well as providing a cationic electrodeposition coating material containing the amine-modified epoxy resin. The solution provided is a modified epoxy resin produced by reaction of at least the following (i) and (ii) and having an average polyfunctionalization degree (X1) per molecule of the modified epoxy resin of 0.10 or greater: (i) a compound (α) having one or more epoxy groups, (ii) a compound (β) having a functional group that is reactive with an epoxy group and that has a total functionality of the functional group of 3 or greater, and/or a compound (γ) having a functional group that is reactive with an epoxy group and that has a total functionality of the functional group of 1 or 2, and the average polyfunctionalization degree (X1) per molecule of the modified epoxy resin being represented by Equation (1) below: Equation (1): Average Polyfunctionalization Degree (X1)=Number of Terminals Per Molecule of Modified Epoxy Resin−2

Dependencies are inferred from the claim text.