Epoxy resin and electrodeposition paint
An epoxy resin, which is obtained by reacting at least a compound having one or more epoxy groups and a compound having a functional group that reacts with the epoxy groups, satisfies conditions (I) and/or (II): (I) the compound having a functional group that reacts with the epoxy groups includes a trihydric or higher phenol compound and/or a compound including a trifunctional or higher polyisocyanate; (II) the epoxy resin has an average degree of polyfunctionalization (X1) per molecule, as expressed by Formula (1), of 0.30 or more: Average degree of polyfunctionalization ( X 1)=number of ends per molecule of epoxy resin−2. Formula (1):
1 . 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; R 1 to R 3 are each independently a monovalent group; R 2 's in n repeating units may be different from each other; when a plurality of R 1 's, R 2 's, and/or R 3 's are present in aromatic rings, the plurality of R 1 's, R 2 's, and/or R 3 's may be the same or different from each other; and R 1 to R 3 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 ( X 1)=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.
2 . The amino-containing epoxy resin according to claim 1 ,
wherein the first epoxy resin has an average concentration of polyfunctionalization (Y1), as expressed by Formula (2) below, of 0.10 or more,
Average concentration of polyfunctionalization ( Y 1)=average degree of polyfunctionalization ( X 1) of epoxy resin: weight-average molecular weight Mw of epoxy resin×1000. Formula (2):
3 . The amino-containing epoxy resin according to claim 1 , wherein the condition (I) is satisfied, and the first epoxy resin is obtained by further reacting a compound having one or more active hydrogens in one molecule that is other than the trihydric or higher phenol compound.
4 . The amino-containing epoxy resin according to claim 1 , wherein the first epoxy resin is obtained by reacting, together with the trihydric or higher phenol compound, a compound represented by structural formula (B) below:
where s is an integer of 0 to 4, and t is an integer of 0 to 4; R 4 and R 5 are each independently a monovalent group; when a plurality of R 4 's and/or R 5 's are present in aromatic rings, the plurality of R 4 's and/or R 4 's may be the same or different from each other; and R 4 and/or R 5 may be bonded to each other to form a ring, wherein a content ratio (mass ratio) of the trihydric or higher phenol compound to the compound represented by structural formula (B) is in a range of 1/99 to 99/1.
5 . The amino-containing epoxy resin according to claim 1 , wherein the trifunctional or higher polyisocyanate comprises isocyanurate isocyanate and/or polymethylene polyphenyl isocyanate represented by structural formula (C) below:
where n is an integer of 1 or greater.
6 . An aqueous resin dispersion comprising the amino-containing epoxy resin according to claim 1 dispersed in an aqueous medium.
7 . A cationic electrodeposition paint comprising the amino-containing epoxy resin according to claim 1 , and a curing agent.
8 . The cationic electrodeposition paint according to claim 7 , wherein the compound having two or more epoxy groups is a compound not modified with amine.
9 . The cationic electrodeposition paint according to claim 7 , further comprising an acrylic resin,
wherein a content of the acrylic resin is less than 30 mass % based on a total amount of all the epoxy resin and the acrylic resin taken as 100 mass %, and
an absolute value of a difference in SP value between the acrylic resin and the epoxy resin is less than 1.0.
10 . A method for producing the cationic electrodeposition paint according to claim 7 , the method comprising:
a step of producing an amino-containing epoxy resin by reacting an amine compound with an epoxy resin obtained by reacting at least a compound having two or more epoxy groups and a trihydric or higher phenol compound and/or a compound including a trifunctional or higher polyisocyanate, the trihydric or higher phenol compound being not a xylene formaldehyde resin; and
a step of mixing the amino-containing epoxy resin and a curing agent to produce a cationic electrodeposition paint.
11 . The method for producing the cationic electrodeposition paint according to claim 10 , wherein the compound having two or more epoxy groups is a compound not modified with amine, and the cationic electrodeposition paint to be produced is a single-layer cationic electrodeposition paint.
12 . A painted article obtained by immersing a coating target in an electrodeposition paint bath containing the cationic electrodeposition paint according to claim 7 and performing electrodeposition.
13 . A single-layer cationic electrodeposition paint comprising:
the amino-containing epoxy resin according to claim 1 ; and
a curing agent.
14 . The cationic electrodeposition paint according to claim 13 , wherein the first epoxy resin used for the amino-containing epoxy resin is obtained by reacting at least the compound having two or more epoxy groups, the compound including a trihydric or higher phenol compound, and a compound having one or more active hydrogens in one molecule that is other than the trihydric or higher phenol compound.
15 . The cationic electrodeposition paint according to claim 14 , wherein the compound having one or more active hydrogens in one molecule that is other than the trihydric or higher phenol compound is a compound represented by structural formula (B) below:
where s is an integer of 0 to 4, and tis an integer of 0 to 4; R 4 and R 5 are each independently a monovalent group; when a plurality of R 4 's and/or R 5 's are present in aromatic rings, the plurality of R 4 's and/or R 5 's may be the same or different from each other; and R 4 and/or R 5 may be bonded to each other to form a ring, and a content ratio by mass of the trihydric or higher phenol compound to the compound represented by structural formula (B) is in a range of 1/99 to 99/1.
16 . The cationic electrodeposition paint according to claim 13 , wherein the trifunctional or higher polyisocyanate comprises isocyanurate isocyanate and/or polymethylene polyphenyl isocyanate represented by structural formula (C) below:
where n is an integer of 1 or greater.
17 . A cationic electrodeposition paint comprising:
the amino-containing epoxy resin according to claim 1 ; and
a curing agent,
wherein a content of the amino-containing epoxy resin is 71 mass % or more based on 100 mass % of resin components other than the curing agent.
18 . The amino-containing epoxy resin according to claim 1 ,
wherein the compound having two or more epoxy groups consists of:
the epoxy compound represented by Formula (D); and/or
the epoxy compound obtained by reaction of polyphenol compounds and epihalohydrin.