JP2002114943A - Epoxy resin paint composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin paint composition being usable on a low temperature painting condition, having a long usable life and excellent painting workability, rapidly curing, and being possible to form a coating having excellent solvent resistance and corrosion resistance. SOLUTION: The epoxy resin paint composition comprises (A) an unsaturated group-containing epoxy resin represented by formula (1), (wherein R1 is a 1-8C alkyl group; and (n) is an integer of 0-2, and preferably 1) comprising reacting a liquid epoxy resin (a) with a carboxyl group-containing unsaturated monomer (b) so that the equivalent ratio of an epoxy group to the carboxyl group can be 1:0.03-0.85 and (B) a ketimine compound comprising blocking with a dialkylketone an amino group of a polyamine compound represented by the formula: Y(-CH2-NH2)k, (wherein Y is a k-valent organic group or a direct bond; and (k) is an integer of >=2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin paint which can be spray-coated even under a low temperature condition of 10 ° C. or less, can be quickly cured in a short time, and can form a coating film having excellent coating properties and corrosion resistance. Composition.

[0002]

2. Description of the Related Art Conventionally, epoxy resins have been
Because of its excellent water resistance, chemical resistance, and adhesion to metal surfaces, it is widely used in various fields such as paints, adhesives, caulks, civil engineering materials, and sealants. In particular, in coating applications, it is generally employed as a highly durable anticorrosive coating, utilizing its excellent adhesiveness based on its resin properties.

[0003] However, these coating compositions are usually difficult to spray-coat because of their relatively high viscosity, and can be applied with a brush or roller.
There is a problem that the fluidity of the paint on the substrate is poor, so that the smoothness of the coated surface is lacking and the finish is poor. In particular, under low-temperature conditions such as an air temperature of 10 ° C. or lower, the paint viscosity further increases, so that the paintability and finishability tend to be remarkably reduced.

As a measure for such a problem, in order to improve paint workability and finishability, in order to reduce paint viscosity,
If a large amount of reactive diluent or non-reactive diluent is blended,
The curability of the coating film rapidly decreases, and it is difficult to obtain stable coating film physical properties and corrosion resistance.

[0005] An object of the present invention is to provide excellent coating workability and good finish even if a large amount of a reactive diluent or a non-reactive diluent is not blended, and to provide a rapid coating under low-temperature coating conditions. An object of the present invention is to obtain a coating material that can be cured to form a coating film having excellent coating film properties such as corrosion resistance.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, they have a specific unsaturated group-containing epoxy resin and a primary amino group bonded to a primary carbon atom. It has been found that a coating composition containing a low-viscosity ketimine compound obtained by blocking an amino group of an amine compound with a dialkyl ketone achieves the above object,
The present invention has been completed. That is, the present invention provides: (A) The following formula

[0007]

Embedded image (Wherein R ¹ represents an alkyl group having 1 to 8 carbon atoms;
Is an integer of 0 to 2, preferably 1). The liquid epoxy resin (a) and the carboxyl group-containing unsaturated monomer (b) represented by the following formula:
An unsaturated group-containing epoxy resin which is reacted so as to be 0.03 to 0.85; and (B) the following formula Y (—CH ₂ —NH ₂ ) _k (where Y is a k-valent organic group or 1. An epoxy resin coating composition comprising a ketimine compound in which an amino group of a polyamine compound represented by a direct bond, and k represents an integer of 2 or more) is blocked by a dialkyl ketone. In the ketimine compound (B), the dialkyl ketone used for blocking is represented by the following formula:

[0008]

Embedded image

Wherein R ² is an alkyl group having 1 to 6 carbon atoms and R ³ and R ⁴ are the same or different and each represent a hydrogen atom, a methyl or an ethyl group. 2. The epoxy resin coating composition according to item 1, which is a ketimine compound. 3. The epoxy resin coating composition according to item 1 or 2, wherein in the ketimine compound (B), the dialkyl ketone used for blocking is methyl isopropyl ketone. 4. The epoxy resin coating composition according to any one of items 1 to 3, wherein the composition is a solventless coating. 5. A coating method, characterized in that the epoxy resin coating composition according to any one of items 1 to 4 is spray-coated on an object without being diluted with a solvent, 5. A coating method, comprising coating the epoxy resin coating composition according to any one of items 1 to 4 on a steel material surface on which rust remains, and curing the coating film to fix the rust. , 7. 5. A coating method, which comprises applying the epoxy resin coating composition according to any one of items 1 to 4 to a steel material surface on which a coating film of an inorganic zinc-rich paint is formed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

First, the epoxy resin coating composition of the present invention will be described in detail. The composition of the present invention is a coating composition containing the following unsaturated group-containing epoxy resin (A) and the following ketimine compound (B) as a vehicle component.

Unsaturated Group-Containing Epoxy Resin (A) The unsaturated group-containing epoxy resin (A) of the present invention is obtained by subjecting a liquid epoxy resin (a) and a carboxyl group-containing unsaturated monomer (b) to an esterification reaction. It can be obtained by

The epoxy resin (a) is, for example, one derived from an alkyl diphenol and epichlorohydrin.

[0014]

Embedded image (Wherein R ¹ represents an alkyl group having 1 to 8 carbon atoms;
Is an integer of 0 to 2 and preferably 1).

Examples of the alkyl group represented by R ¹ in the above formula include methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl, t-butyl, n-hexyl, n-octyl, 2-ethylhexyl and the like. Among them, t-butyl is preferable.

Commercial products of the liquid epoxy resin (a) include, for example, "Epiclon EXA-7120" and "EXCLON EXA-7120".
Alkyl diphenol type epoxy resin such as -6200 (all of which are manufactured by Dainippon Ink and Chemicals, Inc.); "Epiclon EXA-6188" (trade name of Dainippon Ink and Chemicals, Inc.) ) And the like.

In the present invention, it is essential to further introduce an unsaturated group into the epoxy resin (a) in order to improve the initial curability at a low temperature. The resin (A) is
The epoxy resin (a) and the carboxyl group-containing unsaturated monomer (b) are obtained by mixing at least one polymerization inhibitor selected from monohydric or polyhydric phenols and quinones, and optionally an ester. By heating in the presence of a gelling catalyst, it can be obtained without causing gelation.

Examples of the esterification catalyst include ammonium salts such as tetraethylammonium bromide and tetrabutylammonium bromide; tin compounds such as dibutyltin dilaurate; and lithium halides.

Examples of the carboxyl group-containing unsaturated monomer (b) include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) ) Acrylate, 5-carboxypentyl (meth) acrylate, and the like. Particularly, when acrylic acid is used, it is particularly preferable because the curability of the coating film is good.

The ratio of the epoxy resin (a) to the carboxyl group-containing unsaturated monomer (b) is 1: 0.03 to 0.85, preferably 1: 1, in terms of an equivalent ratio of the epoxy group to the carboxyl group.
It is preferable to make the reaction to be 0.05 to 0.5. If it is less than 0.03, the low-temperature curability is insufficient. On the other hand, if it exceeds 0.85, the curing reaction proceeds rapidly, the working life of the paint is short-circuited, and the corrosion resistance of the obtained coating film is deteriorated. Is not preferred.

Ketimine Compound (B) The ketimine compound (B) used in the present invention comprises:
A curing agent for the unsaturated group-containing epoxy resin (A),
The amino group of the polyamine compound represented by the following formula Y (—CH ₂ —NH ₂ ) _k (where Y represents a k-valent organic group or a direct bond, and k represents an integer of 2 or more) is a dialkyl ketone Is a ketimine compound blocked by

The polyamine compound represented by the above formula is
A primary amino group bonded to a primary carbon atom in the molecule
The compound may have any one of aliphatic, alicyclic and aromatic compounds. The polyamine compound generally has a concentration of about 2,000 or less, preferably about 30
Advantageously, it has a primary amino group equivalent in the range of from about 1,000 to about 1,000, and generally has a number average molecular weight in the range of about 5,000 or less, preferably in the range of about 60 to 3,000. Is preferred.

Specific examples of the above polyamine compound include:
Aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine; aromatic polyamines such as meta-xylylenediamine, diaminodiphenylmethane, and phenylenediamine; 1,3-bis Alicyclic polyamines such as (aminomethyl) cyclohexane, isophoronediamine, norbornanediamine, and the like;

Among the above polyamine compounds, a polyamine compound having no secondary amino group in the molecule, that is, a polyamine compound having only a primary amino group which can be blocked by a carbonyl compound as an amino group having an active hydrogen atom, It is particularly suitable because it has good storage stability after being mixed with the epoxy resin. When a ketimine compound having a secondary amino group in a molecule is used, an adduct consumed by reacting the secondary amino group with an isocyanate compound to urethanize (ureaize) the secondary amino group is used. It is desirable to use it as a compound.

Preferred dialkyl ketones used for blocking the primary amino group of the polyamine compound include, for example, the following formulas from the viewpoint of the balance between curability and storage stability.

[0026]

Embedded image Wherein R ² is an alkyl group having 1 to 6 carbon atoms, and R ³ and R ⁴ are the same or different and each represent a hydrogen atom, a methyl or an ethyl group.

In the above formula, the alkyl group having 1 to 6 carbon atoms represented by R ² includes methyl, ethyl, n-
Propyl, isopropyl, n-butyl, isobutyl, n
-Hexyl and the like, and among them, an alkyl group having 1 to 3 carbon atoms is preferable.

The ketone represented by the above formula includes, for example, methyl ethyl ketone, methyl isopropyl ketone,
Examples thereof include methyl isobutyl ketone, methyl t-butyl ketone, methyl sec-butyl ketone, and methylhexyl ketone. Among them, methyl isopropyl ketone and methyl isobutyl ketone are preferable.

The reaction between the polyamine compound and the dialkyl ketone can be carried out by a method known per se, wherein substantially all of the primary amino groups present in the polyamine compound are replaced with the dialkyl ketone. Reaction under quantitative conditions and reaction conditions that react (dehydration reaction)
It is desirable to make it.

The ketimine compound obtained by reacting the polyamine compound with the ketone represented by the above formula is represented by the following formula:

[0031]

(Equation 5) (Wherein, Y represents a k-valent organic group or a direct bond, and k represents 2
In the repeating unit, each R ² represents the same or different alkyl group having 1 to 6 carbon atoms, and each R ³ and R ⁴ represent the same or different hydrogen atom, methyl or ethyl group. Can be represented by

In the coating composition of the present invention, the compounding ratio of the ketimine compound (B) is based on 1 equivalent of the total of the epoxy group and the unsaturated group in the unsaturated group-containing epoxy compound (A). The active hydrogen bonded to the primary amino group generated by elimination of the ketone from B) is 0.5 to
It is desirable to use 3.0 equivalents, preferably 0.8 to 1.5 equivalents, from the viewpoints of curability, non-adhesion, and corrosion resistance of the coating film.

The coating composition of the present invention contains the unsaturated group-containing epoxy resin (A) and the ketimine compound (B) as essential components, and if necessary, a reactive diluent and a dehydrating agent. Modified resin components such as modified epoxy resin having no epoxy group, xylene resin, toluene resin, ketone resin, coumarone resin, petroleum resin, alkyd resin, and boil oil stand oil; zinc powder, aluminum powder, etc. Metal powders; pigments such as color pigments, extender pigments, and rust-preventive pigments; and additives such as thickeners, plasticizers, fillers, and dispersants.

The reactive diluent optionally contained in the coating composition of the present invention may be a low-viscosity compound having one epoxy group in the molecule. Representative examples of the reactive diluent include, for example, glycidyl ethers having one glycidyl group in one molecule such as n-butyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether; glycidyl methacrylate Glycidyl esters having one glycidyl group in one molecule; styrene oxide; Commercially available reactive diluents include, for example, “Kajura E” (trade name, manufactured by Shell Chemical Company, glycidyl ester of higher branched fatty acid), and “Epiclon 703” (trade name, manufactured by Dainippon Ink and Chemicals, Inc., trade name) And glycidyl esters of higher alcohols) and "Epiclon 520" (trade name, glycidyl ether of butylated phenol, manufactured by Dainippon Ink and Chemicals, Inc.). The amount of the reactive diluent to be used is within the range of 30% by weight or less, preferably 20% by weight or less based on the solid content of the coating material, in view of the curability, physical properties, corrosion resistance, water resistance, etc. It is.

As the dehydrating agent optionally contained in the coating composition of the present invention, known dehydrating agents can be used. Representative examples thereof include methyl orthoformate, ethyl orthoformate, and orthoacetic acid. Examples thereof include methyl, ethyl orthoacetate, and dimethoxypropane. These dehydrating agents can be used alone or in combination of two or more. The amount of the dehydrating agent is not particularly limited, but is generally 15% based on the weight of the coating composition. It is appropriate that the content is not more than 0.5% by weight, preferably in the range of 0.5 to 10% by weight.

The coating composition of the present invention may be a solvent-free coating containing no solvent.
If necessary, an organic solvent can be contained. Any organic solvent can be used without particular limitation as long as it can dissolve or disperse the unsaturated group-containing epoxy resin (A) and the ketimine compound (B). By blending a ketone solvent as a part of the organic solvent, the formation of amino groups due to the decomposition of the ketimine compound during storage of the coating can be suppressed, which is advantageous for a one-pack coating. It is preferable that the content of the organic solvent in the coating material is usually 30% by weight or less from the viewpoint of curability.

The coating composition of the present invention has a viscosity of 5, when applied.
000 mPa · s or less, preferably 3,000 mPa · s
s or less, and the coating form may be a one-pack type or a two-pack type. The viscosity of the coating composition of the present invention can be considerably reduced even when the coating composition does not contain an organic solvent, so that the coating composition can be spray-coated on a substrate without being diluted with a solvent.

The composition of the present invention can be used for a material surface such as metal (iron, aluminum, zinc), wood, plastic, stone, slate, concrete, mortar, etc., or an old coating surface on these materials, and rust remains. Can be applied to the surface of a steel material or the surface of a steel material on which a coating of inorganic zinc-rich paint is formed. As a coating method, a general coating method such as brush coating, spray coating, and various coater coatings can be used.

When the coating composition of the present invention is applied to the surface of a steel material on which rust remains, the rust is fixed by sufficiently penetrating into the rust and hardening, thereby compensating for the mechanical strength of the rust. The effect of strongly and stably adhering to the lower steel material ground and forming a strong coating film together with rust can be exhibited.

When the coating composition of the present invention is applied to the surface of a steel material on which an inorganic zinc-rich paint coating has been formed, a large number of voids (voids) in the inorganic zinc-rich paint coating are filled to form voids. The effect of preventing the generation of defects such as foaming and pinholes due to air inside can be exhibited.

The coating amount of the coating composition of the present invention is not particularly limited, but is generally about 10 to 150 μm, preferably about 10 μm in dry film thickness in the case of a clear coating.
１００100 μm, in the case of an enamel paint containing a pigment, about 10-500 μm, preferably about 25-3
A range of 00 μm is appropriate.

Further, a top coat can be applied as needed on the coating film obtained by applying and drying the coating composition of the present invention. The overcoat is not particularly limited, and any known overcoat can be used, such as alkyd resin, chlorinated rubber, epoxy resin, silicon alkyd resin, urethane resin, silicone acrylic, and fluororesin. Paints can be used.

[0043]

Industrial Applicability The coating composition of the present invention has a low viscosity.
Spray coating is possible even under low-temperature coating conditions of 0 ° C. or lower, and the coating workability is excellent. In addition, since the pot life is long, a continuous coating operation can be stably performed without sharply increasing the viscosity of the coating during coating.

Further, the coating composition of the present invention cures quickly even under low temperature conditions, and can form a coating film having excellent adhesion, corrosion resistance and impact resistance.

[0045]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. In Examples, "parts" and "%" indicate "parts by weight" and "% by weight" unless otherwise specified.

Production Example 1 "Epiclon EXA7120" (Note 1) 100 was placed in a reaction vessel equipped with a thermometer, thermostat, stirrer, and reflux condenser.
0 parts, 15.7 parts of acrylic acid, 0.016 parts of t-butylated hydroxytoluene as a polymerization inhibitor, and 2 parts of tetrabutylammonium bromide as a reaction catalyst were charged into a flask, and the temperature was raised to 105 ° C. while blowing air. . Thereafter, the esterification reaction was performed for 4 hours while controlling the reaction temperature in the range of 105 ° C to 115 ° C, and the reaction was terminated when the resin acid value reached 0 mgKOH / g,
An unsaturated group-containing epoxy resin (A) having a solid content of 100% and a functional group equivalent of 234 was obtained. Here, the functional group equivalent refers to the total equivalent of the epoxy group and the unsaturated group that can react with the amino group having active hydrogen.

Production Examples 2 to 9 The same operation as in Production Example 1 was carried out, except that the composition was changed as shown in Table 1 below, to obtain each resin (B).
To (I). (Note 1) and (Note 2) in Table 1
Has the following meaning.

[0048]

[Table 1]

Note 1) "Epiclone EXA7120": trade name, manufactured by Dainippon Ink and Chemicals, an alkyl diphenol type liquid epoxy resin Note 2) "Epiclon EXA6200": trade name, manufactured by Dainippon Ink and Chemicals, alkyldi Phenol type liquid epoxy resin.

Production of Coating Composition Example 1 40 parts of unsaturated group-containing epoxy resin (A), 10 parts of bengara (Note 3), 28 parts of talc (Note 4), "Dispalon 6
900-20X ”(Note 5) 2 parts and xylene 7 parts were sequentially charged while stirring with a disper, according to JIS K-5400.
According to the method of dispersion A, dispersion was carried out with a sand mill until the tub became 40 μm or less, to obtain a dispersion base. Then, 14 parts of a curing agent A (Note 6) shown in Table 2 below was added to the dispersion base and mixed to obtain a coating composition (T1). Note 3) Bengala: “Todacolor 520R”, manufactured by Toda Kogyo Co., Ltd., iron oxide, pigment Note 4) Talc: “Talc No. 2”, manufactured by Takehara Chemical Industry Co., Ltd., magnesium silicate Note 5) “Dispalon 6900-20X”: Kusumoto Kasei 6) Curing agent A: meta-xylylenediamine methyl isobutyl ketone reactant, molecular weight of about 300 Note 7) Curing agent B: meta-xylylene diamine methyl isopropyl ketone reactant, molecular weight of about 300 272.

Production Examples 2 to 9 and Comparative Examples 1 to 4 The same operation as in Example 1 was carried out except that the composition was as shown in Table 2 below, and each coating composition (T2) To (T14).

[0052]

[Table 2]

Each of the coating compositions obtained in Examples 1 to 9 and Comparative Examples 1 to 4 was subjected to various tests according to the following test methods. Table 3 shows the test results.

Test Method Pot Life 800 g of each coating composition was collected in a 1-liter round can, sealed, and allowed to stand at 20 ° C. for 7 days to observe the state of the coating. The evaluation was based on the following criteria. ：: No abnormality, Δ: Large increase in viscosity, ×: Gelation.

Spray coatability Each paint composition was applied to Airless Tip # 5 manufactured by Nippon Gray Co., Ltd.
Using No. 19, the film forming property and atomization of the coating film when airless coating was performed at a temperature of 25 ° C. were comprehensively evaluated. ：: good, △: slightly poor, ×: bad.

Rust Surface Compatibility A test plate was prepared by removing a brittle rust layer on the entire surface of a steel plate having rust on the entire surface with a wire brush as much as possible. Each coating composition was painted on a test plate so as to have a thickness of 100 μm, and the temperature was 20 ° C. and the relative humidity was 65%.
After curing for one day, the adhesion of the coating film was evaluated using an adhesion tester. ：: 20 kgf / cm ² or more, Δ: less than 20 kgf / cm ² to 10 kgf / cm ² or more, ×: less than 10 kgf / cm ² .

Inorganic zinc-rich surface compatibility A sandblasted steel sheet coated with an inorganic zinc-rich paint at a film thickness of 75 μ was used as a test plate. Each coating composition was spray-coated on the surface of the inorganic zinc-rich coating film so as to have a thickness of 100 microns, and the presence or absence of bubbles generated from the inorganic zinc-rich coating film was evaluated. ：: no bubble generation, Δ: partial bubble generation, ×:
The entire surface of foam generation.

Curability: Each coating composition is applied on a 200 × 100 mm tin plate with a brush so that the dry film thickness is 50 to 70 μm, and left in an atmosphere at a temperature of 20 ° C. and a relative humidity of 65%. After 8 hours, the state of the coating film was changed to JIS K5
The evaluation was performed according to the description of 400 6.5. ：: cured state Δ: semi-cured state ×: uncured state

Low-temperature physical properties 1) Low-temperature curability: The same procedure was carried out as in the method described in the section on curability, except that the composition was allowed to stand in a low-temperature constant temperature oven at 5 ° C. The numerical values in the table indicate the time required to reach a semi-cured state. The smaller the value, the better.

2) Gel fraction: 200 × 1 of each coating composition
Dry film thickness of 50 mm with a brush on a 00 mm polypropylene plate
Apply to a low temperature incubator at 5 ° C.
It was allowed to stand horizontally for 8 hours. Thereafter, the coating film was peeled off from the obtained coated plate, and about 1 g was wrapped in a 330-mesh silk screen and immersed in xylene. After 24 hours, each sample was pulled up, dried at 105 ° C. for 60 minutes, and the gel fraction of the coating film was determined by the following formula. Weight) x 100.

3) Solvent resistance: Each coating composition was 300 × 1
Dry film thickness of 50-70 μm with brush on 00mm mild steel plate
And placed horizontally in a 5 ° C. low temperature oven for 24 hours. Then, on each of the obtained painted plates, 0.1c
About ³ m ^{3 of} an epoxy resin paint thinner was dropped, and the degree of dissolution of the coating film was visually evaluated. The evaluation was based on the following criteria. ：: No change in coating film Δ: Swelling of coating film X: Dissolution of coating film.

Coating Performance Test Preparation of Test Coating Plates Each coating composition was applied to a 150 × 70 mm mild steel plate in the same manner as described above, and was subjected to 20 ° C. and 65% relative humidity.
Was dried for 7 days under the conditions described above to obtain a test coated plate.

1) Accelerated corrosion protection: A cross cut was made on each test coated plate until it reached the substrate, and a salt spray test was performed at 35 ° C. for 2 hours.
The sample was subjected to 40 hours, and the degree of rust and blister was evaluated according to the following criteria. ○: No abnormality Δ: Partially rust and blistering ×: Rust and blistering occurred entirely.

2) Adhesion: JIS K 5400
According to 5.3, cut each test coated plate into a 25 mm grid with a width of 2 mm, adhere Cellotape (registered trademark) from above, immediately peel off the tape, and check the number of remaining adhered grids. ：: 10 to 8 points Δ: 7 to 5 points ×: 4 points or less. 3) Impact resistance: 500 mm for each test coated plate according to the DuPont impact resistance test described in JIS K5400 8.3.2.
A shock was applied from a height of 300 g with a bomb with a weight of 300 g, a cellophane tape was brought into close contact with the impacted portion, the tape was instantaneously peeled off, and the degree of peeling of the coating film was evaluated. ：: No peeling was observed on the coated surface. X: Significant peeling was observed on the coated surface.

[0065]

[Table 3]

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Sumio Noda 4-171-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa F Kansai Paint Co., Ltd. F-term (reference) 4D075 AA01 DB02 EB33 4J038 DB081 DB361 DB371 JB18 KA03 NA01 NA03 NA04 NA24 PA06 PB12 PC02

Claims (7)

[Claims] (A) The following formula: (Wherein R ¹ represents an alkyl group having 1 to 8 carbon atoms;
Is an integer of 0 to 2, preferably 1). The liquid epoxy resin (a) and the carboxyl group-containing unsaturated monomer (b) represented by the following formula:
An unsaturated group-containing epoxy resin which is reacted so as to be 0.03 to 0.85; and (B) the following formula Y (—CH ₂ —NH ₂ ) _k (where Y is a k-valent organic group or An epoxy resin coating composition comprising a ketimine compound in which an amino group of a polyamine compound represented by the following formula (1) represents a direct bond, and k represents an integer of 2 or more). 2. In the ketimine compound (B), the dialkyl ketone used for blocking is represented by the following formula: Wherein R ² is an alkyl group having 1 to 6 carbon atoms, and R ³ and R ⁴ are the same or different and each represent a hydrogen atom, a methyl or an ethyl group. The epoxy resin coating composition according to claim 1, wherein 3. The epoxy resin coating composition according to claim 1, wherein in the ketimine compound (B), the dialkyl ketone used for blocking is methyl isopropyl ketone. 4. The epoxy resin coating composition according to claim 1, which is a solventless coating. 5. A coating method comprising spray-coating the epoxy resin coating composition according to any one of claims 1 to 4 on an object without diluting with a solvent. 6. A method of applying the epoxy resin coating composition according to any one of claims 1 to 4 to a surface of a steel material on which rust remains, and curing the coating film to fix the rust. Characteristic coating method. 7. A coating method, wherein the epoxy resin coating composition according to claim 1 is applied to a surface of a steel material on which a coating film of an inorganic zinc-rich paint is formed.