Epoxy resin and electrodeposition paint

An amino-containing epoxy resin obtained by reacting a first epoxy resin and an amine compound, said first epoxy resin being obtained, without a dimer acid diglycidyl ester, by reacting at least:

• a compound having two or more epoxy groups;
• and
• a compound having a functional group that reacts with the epoxy groups,
• wherein the amino-containing epoxy resin has an average degree of polyfunctionalization (X2), as expressed by Formula (3) below, of 0.60 to 13.0:
• Formula (3):
• Average degree of polyfunctionalization (X2)=number of ends in one molecule of amino-containing epoxy resin-2,
• wherein the compound having two or more epoxy groups is comprised of:
• an epoxy compound represented by Formula (D):
• where n is 0 to 8;
• and/or
• an epoxy compound obtained by reaction of polyphenol compounds and epihalohydrin,
• wherein the first epoxy resin satisfies conditions (I) and/or (II) below:
• (I) the compound having a functional group that reacts with the epoxy groups comprises a trihydric or higher phenol compound and/or a compound including a trifunctional or higher polyisocyanate, wherein the trihydric or higher phenol compound includes a compound represented by structural formula (A) below:
• where n is an integer of 1 to 20, p is an integer of 0 to 4, q is an integer of 0 to 3, and r is an integer of 0 to 4;
• R1 to R3 are each independently a monovalent group;
• R2's in n repeating units may be different from each other;
• when a plurality of R1's, R2's, and/or R3's are present in aromatic rings, the plurality of R1's, R2's, and/or R3's may be the same or different from each other;
• and R1 to R3 may be bonded to each other to form a ring,
• (II) the first epoxy resin has an average degree of polyfunctionalization (X1) per molecule, as expressed by Formula (1) below, of 0.60 to 13.0:
• Average degree of polyfunctionalization (X1)=number of ends per molecule of epoxy resin−2, Formula (1):
• wherein the number of ends per molecule of epoxy resin refers to the number of ends having an epoxy group or a functional group that reacts with the epoxy group in one molecule of the first epoxy resin, which is the number of functional group-containing molecular ends resulting from branching of a main chain of the first epoxy resin in which an epoxy group of the compound having two or more epoxy groups and a secondary hydroxyl group of another compound having two or more epoxy groups are reacted with each other.