JP2001323212A - Epoxy resin-based coating composition and method for coating by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin-based coating composition useful for reinforcement of weak and deteriorated surface such as an inorganic building material and an old coated film surface, and capable of forming a coated film excellent in penetrability, film-formability, and suitability for final coating, and further to provide a method for coating by using the composition. SOLUTION: This coating material containing (A) an epoxy resin having >=2,000 mPa.s viscosity at 25 deg.C, and dissolvable in the following organic solvent (D), (B) an epoxy resin having <2,000 mPa.s viscosity at 25 deg.C and dissolvable in the following organic solvent (D), (C) an amine-based curing agent, and (D) the organic solvent, and the organic solvent (D) contains >=80 wt.% hydrocarbon- based solvent selected from an aliphatic hydrocarbon-based solvent and a high- boiling-point aromatic hydrocarbon-based solvent having >=148 deg.C boiling point, in the organic solvent (D).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin system which can form a coating film having excellent permeability, film forming property and suitability for top coating, which is useful for reinforcing brittle and deteriorated surfaces such as inorganic building materials and old coating surfaces. The present invention relates to a coating composition and a coating method using the same.

[0002]

2. Description of the Related Art
When coating the inside and outside walls of buildings and roof tiles, cement-based inorganic building materials such as concrete, mortar, slate boards, and siding boards have a weak surface layer. A primer is applied to the surface of the building material in order to secure adhesion and adhesion to a coating film or the like. In addition, a primer is also applied during the repair painting of the surface where the deteriorated old paint film remains.

As such primers, organic solvent-type primers containing an epoxy resin and an amine-based curing agent as main components are often used. However, such primers have high volatility such as ketone-based solvents and are flammable. There are problems in safety and hygiene, such as easy use of strong solvents and adverse effects on the human body due to suction. Further, when a primer containing a large amount of such a strong solvent is applied on an old coating film, the old coating film is eroded by the solvent, causing a problem such as lifting.

[0004] It is an object of the present invention to provide an epoxy resin-based coating composition capable of forming a coating film having excellent penetration reinforcing properties and excellent film forming properties, and further having excellent drying properties, suitability for top coating, and excellent adhesion.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and have found that they have been successfully diluted with an aliphatic hydrocarbon solvent and a high-boiling aromatic hydrocarbon solvent having a boiling point of 148 ° C. or higher. The present inventors have found that the above object can be achieved by a coating composition containing two types of epoxy resins and an amine-based curing agent, thereby completing the present invention.

That is, according to the present invention, (A) the viscosity is 25 ° C.
An epoxy resin having a viscosity of less than 2,000 mPa · s at 25 ° C. and an epoxy resin having a viscosity of less than 2,000 mPa · s at 25 ° C. A paint containing a liquid epoxy resin soluble in an organic solvent (D), (C) an amine-based curing agent, and (D) an organic solvent, wherein the organic solvent (D) is an aliphatic hydrocarbon-based solvent and An epoxy resin-based coating composition characterized in that the organic solvent (D) contains at least 80% by weight of a hydrocarbon solvent selected from high-boiling aromatic hydrocarbon solvents having a boiling point of 148 ° C. or higher. The present invention relates to a coating method of applying the same to a surface to be coated and further applying a top coat.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the epoxy resin (A) has a viscosity of not less than 2,000 mPa · s at 25 ° C., preferably not less than 2300 mPa · s. A resin having one or more epoxy groups therein, preferably two or more on average, more preferably 2 to 5 on average, having a number average molecular weight of about 500 to 3,000, preferably about 750 to 2,000. Epoxy equivalents within the range of about 100 to 2,000, preferably about 200 to 2,000.
It is desirable to be in the range of 1500, and it is an epoxy resin that can be dissolved in an organic solvent (D) described later.

As the epoxy resin (A), for example, at least one epoxy resin selected from glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, other glycidyl ether type epoxy resin, and alicyclic epoxy resin is used. And a modified epoxy resin modified with an alkylphenol or / and a fatty acid, or an epoxyphenol-introduced alkylphenol or alkylphenol novolak-type resin obtained by reacting an alkylphenol or alkylphenol-novolak-type resin with epichlorohydrin.

The glycidyl ether type epoxy resin is, for example, an epoxy resin having a glycidyl ether group obtained by reacting a polyhydric alcohol, a polyhydric phenol or the like with epichlorohydrin or an alkylene oxide. Examples of the polyhydric alcohol include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, neopentyl glycol, butylene glycol, hexanediol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, diglycerin, sorbitol and the like. Can be mentioned. Examples of the polyhydric phenol include 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] and 2,2-bis (4-hydroxyphenyl) propane [bisphenol A].
Bis (2-hydroxyphenyl) propane, 2- (2-
Hydroxyphenyl) 2- (4-hydroxyphenyl)
Propane, halogenated bisphenol A, bis (4-hydroxyphenyl) methane [bisphenol F], tris (4-hydroxyphenyl) propane, resorcinol,
Examples thereof include tetrahydroxyphenylethane, 1,2,3-tris (2,3-epoxypropoxy) propane, novolak-type polyhydric phenol, and cresol-type polyhydric phenol.

Examples of the glycidyl ester type epoxy resin include diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, and diglycidyl dimer.

Examples of the other glycidyl type epoxy resins include tetraglycidylaminodiphenylmethane, triglycidyl isocyanurate and the like.

Examples of the alicyclic epoxy resin include (3,4-epoxy-6-methylcyclohexyl) methyl-3,4-epoxy-6-methylcyclohexanecarboxylate and (3,4-epoxycyclohexyl) methyl- 3,4-epoxycyclohexanecarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, Eporide GT300 (Daicel Chemical Industries, Ltd.)
, Trade name, trifunctional alicyclic epoxy resin), Eporide GT400 (manufactured by Daicel Chemical Industries, Ltd., trade name; tetrafunctional alicyclic epoxy resin), EHPE (manufactured by Daicel Chemical Industries, Ltd.), trade name, Polyfunctional alicyclic epoxy resin).

The epoxy resin before modification preferably has an average epoxy equivalent of about 250 or less.

As the alkylphenol that can be used as the above modifier, a phenol having an alkyl group having about 2 to 18 carbon atoms is preferable.
-Butylphenol, paraoctylphenol, nonylphenol and the like. In addition, as the fatty acid that can be used as the denaturing agent, a drying oil fatty acid and a semi-dry oil fatty acid are preferable. Specific examples thereof include linseed oil fatty acid, safflower oil fatty acid, soybean oil fatty acid, sesame oil fatty acid, eno oil fatty acid, and hemp oil. Fatty acids, grape kernel oil fatty acids,
Krill oil fatty acid, corn oil fatty acid, sunflower oil fatty acid, cottonseed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid,
Deer oil fatty acids, fish oil fatty acids, high diene fatty acids,
Tall oil fatty acids and dehydrated castor oil fatty acids can be mentioned. The above modifiers, alkylphenols and fatty acids, can be used alone or in admixture of two or more.

The above-mentioned modified epoxy resin is prepared by subjecting the unmodified epoxy resin and a modifying agent such as alkylphenol and / or fatty acid to 100 to 20 in the presence of a catalyst, if necessary.
It can be obtained by heating to 0 ° C. The reaction between the epoxy resin and the modifier before modification is based on the former ratio of the equivalent of the epoxy group in the epoxy resin to the total equivalent of the hydroxyl group in the alkylphenol and the carboxyl group of the fatty acid:
It is preferable to mix and react so as to be in the range of 1: 0.2 to 0.6 in the latter ratio.

As the epoxy resin (A), in particular, a modified epoxy resin obtained by modifying a bisphenol A type epoxy resin with an alkylphenol or / and a fatty acid is used in view of the film forming property and toughness of the resulting coating film. It is suitable.

In the present invention, the liquid epoxy resin (B)
Has a viscosity of less than 2000 mPa · s at 25 ° C., preferably 1
800 mPa · s or less, a resin having one or more, preferably two or more epoxy groups on average per molecule, having a number average molecular weight of about 350 to 2,000, preferably about 500 to 1,000. It is desirable that the epoxy equivalent is in the range of about 80 to 1,000, preferably about 200 to 800, and the epoxy resin is soluble in the organic solvent (D) described below.

Representative examples of the liquid epoxy resin (B) include, for example, an epoxy resin derived from an alkyldiphenol and epichlorohydrin, an epoxy resin derived from an alkylphenol novolak and epichlorohydrin, a bisphenol F type epoxy resin, and hydrogenated bisphenol. A type epoxy resin, hydrogenated bisphenol F type epoxy resin and the like can be mentioned. Among them, an epoxy resin derived from an alkyldiphenol and epichlorohydrin is preferable, and for example, the following formula (1)

[0019]

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

The alkyl group represented by R in the above formula includes methyl, ethyl, isopropyl, n-propyl, n-butyl, isobutyl, t-butyl, n-hexyl, n-octyl, 2-ethylhexyl and the like. In particular, t-butyl is preferable.

Commercial products of the liquid epoxy resin (B) include, for example, EPICLON EXA-7120 and EXCLON-620.
0 (both manufactured by Dainippon Ink and Chemicals, Inc.)
Alkyl diphenol type epoxy resin such as Epiclon EXA-6188 (manufactured by Dainippon Ink and Chemicals, Inc.)
Alkylphenol novolak type epoxy resins such as;
Bisphenol F type epoxy resins such as Epicoat 806, 806L, and 1750 (all of which are manufactured by Yuka Shell Epoxy Co., Ltd.); Epicoat YL666
Hydrogenated bisphenol A type epoxy resin such as No. 3 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd.); Epicoat YL67
Hydrogenated bisphenol F type epoxy resin such as 53 (trade name, manufactured by Yuka Shell Epoxy Co., Ltd.) can be used.

In the present invention, the epoxy resin (A)
The mixing ratio of the liquid epoxy resin (B) and the liquid epoxy resin (B) is not particularly limited, but (A) / (B) = 90/10 to 30/7 in terms of solid content.
It is suitably within the range of 0, preferably within the range of 90/10 to 50/50. When the ratio of the resin (A) is larger than the mixing ratio, the permeability is reduced and the reinforcement of the base material is insufficient. On the other hand, when the ratio of the resin (B) is higher than the mixing ratio, the film forming property is lowered, and the bleeding preventing property and the overcoating are reduced. It is not preferable because aptitude is inferior.

In the present invention, the amine-based curing agent (C) comprises:
It is a curing agent for the epoxy resin (A) and the liquid epoxy resin (B), and conventionally known ones can be used without any particular limitation. Examples of the amine-based curing agent include a polyamine compound.

The above-mentioned polyamine compound is the first compound in one molecule.
It is a compound having two or more primary amino groups bonded to a primary carbon atom, and may be any of aliphatic, alicyclic and aromatic. Advantageously, the polyamine compound generally has a primary amino group equivalent weight of about 2000 or less, preferably in the range of about 30 to about 1000, and generally has a primary amino group equivalent of about 5000 or less, preferably about 60 to 300.
It is preferred to have a number average molecular weight in the range of 0.

Examples of the polyamine compound include ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine,
Aliphatic polyamines such as triethylenetetramine and pentaethylenehexamine; aromatic polyamines such as meta-xylylenediamine, diaminodiphenylmethane and phenylenediamine; alicyclic polyamines such as 1,3-bis (aminomethyl) cyclohexane and isophoronediamine And the like.

Further, as the amine-based curing agent (C), a ketimine compound in which the amino group of the above-mentioned polyamine compound is blocked by a dialkyl ketone can also be mentioned. By using the ketimine compound, the composition of the present invention can be made into a one-part composition. In this case, among the above polyamine compounds, polyamine compounds having no secondary amino group in the molecule, that is, having only a primary amino group that can be blocked by a carbonyl compound as an amino group having an active hydrogen atom, Is particularly preferred because of good storage stability after mixing with the resins (A) and (B). When a ketimine compound having a secondary amino group in the molecule is used, it is desirable to use the ketimine compound as an adduct compound in which the secondary amino group is consumed by reacting the secondary amino group with an epoxy compound.

Suitable dialkyl ketones for use in blocking the primary amino group of the polyamine compound include, for example, the following formula (2) from the viewpoint of a balance between curability and storage stability.

[0028]

Embedded image (Wherein, R ¹ is an alkyl group having 1 to 6 carbon atoms, R ² is an alkyl group having 1 to 6 carbon atoms, R ³ and R ⁴ are the same or different and represent a hydrogen atom, a methyl or ethyl group) The compound shown by these can be mentioned.

In the above formula, the alkyl group having 1 to 6 carbon atoms represented by R ¹ and R ² includes methyl, ethyl,
Examples thereof include n-propyl, isopropyl, n-butyl, isobutyl, and n-hexyl. Among them, an alkyl group having 1 to 3 carbon atoms is preferable.

Examples of the ketone represented by the above formula include 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 is 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. It is desirable to carry out the reaction (dehydration reaction) at such a quantitative ratio and reaction conditions as to cause the reaction.

The amine-based curing agent (C) preferably has a viscosity of not more than 500 mPa · s at 25 ° C. from the viewpoint of the effect of reinforcing the surface to be coated.

In the present invention, the above amine curing agent (C)
The active hydrogen in the amine-based curing agent (C) is 0.5 to 3.0 equivalents based on 1 equivalent of the epoxy group in the epoxy compound (A) and the liquid epoxy compound (B).
It is preferable to use 0.8 to 1.5 equivalents in terms of curability, non-adhesion, and corrosion resistance of the coating film.

In the present invention, the organic solvent (D) is used for the purpose of uniformly dissolving or dispersing each component of the coating composition, adjusting the viscosity, and the like. It is necessary not to cause lifting of the old coating film when over-applied, and the aliphatic hydrocarbon solvent and boiling point 1
80% by weight of a hydrocarbon solvent selected from high-boiling aromatic hydrocarbon solvents of 48 ° C. or higher in the organic solvent (D)
It contains the above.

Specific examples of the above-mentioned aliphatic hydrocarbon solvents and high-boiling aromatic hydrocarbon solvents include, for example, VM & P
Naphtha, Mineral Spirit, Solvent Kerosene, Aromatic Naphtha, Solvent Naphtha, Solvesso 100, Solvesso 150, Solvesso 200 [“Solvesso” is a registered trademark of Esso Oil Co., Ltd.], Swazol 310, Swazol 1000, Swazol 1500 [“Swazol” is Cosmo Aliphatic or aromatic hydrocarbons having relatively low dissolving power, such as n-butane, n-hexane, n-heptane, n-octane, isononane, n-decane, n-dodecane And aliphatic hydrocarbons such as cyclopentane, cyclohexane and cyclobutane.

It is desirable that all of the organic solvent in the composition of the present invention is an aliphatic hydrocarbon solvent or a high-boiling aromatic hydrocarbon solvent. It may contain 20% or less, preferably 10% or less of other organic solvents other than the boiling aromatic hydrocarbon solvent. When the amount of the other organic solvent increases, lifting of the old coating film easily occurs at the time of recoating.

The content of the organic solvent (D) is not particularly limited as long as the paint state and the paint viscosity can be maintained in an appropriate range, and is usually 20 to 90% by weight in the paint. Quantity.

[0038] The coating composition of the present invention comprises the above (A) to
The component (D) is essential, and a one-pack or two-pack coating composition can be obtained depending on the component (C). The composition of the present invention, if necessary, a reactive diluent, a dehydrating agent, a modifying resin component, a coloring pigment, an extender pigment,
It may contain pigments such as rust preventive pigments, and additives such as thickeners, plasticizers and dispersants.

Examples of the dehydrating agent include methyl orthoformate, ethyl orthoformate, dimethoxypropane and the like, and are useful when the coating composition of the present invention is made into a one-pack type.

The present invention also provides a coating method in which the coating composition of the present invention obtained as described above is applied to a surface to be coated, and further a top coat is applied.

The surface to be coated may be, for example, a metal (iron, aluminum, zinc, etc.), wood, plastic, stone, slate, concrete, mortar, siding board, or the like, or an old coating surface on these materials. Is mentioned. In particular, it is preferable to apply the coating composition of the present invention as a primer to a fragile or deteriorated surface such as an inorganic building material surface such as slate, concrete, mortar, and siding board and an old paint film surface. As the coating method, a general method such as brush coating, roller coating, spray coating, or various coater coatings can be used.

The coating amount of the composition of the present invention is not particularly limited, but is generally about 0.05 to 0.5 kg / m ² , preferably about 0.1 to 0.5 kg / m ^{2 for} clear paint.
In the case of an enamel paint containing 0.25 kg / m ² and a pigment, a range of about 0.05 to 1.0 kg / m ² , preferably about 0.1 to 0.5 kg / m ² is appropriate. .

The overcoat paint is not particularly limited, and a known overcoat paint can be used. Examples thereof include alkyd resin, acrylic resin, chlorinated rubber, epoxy resin, and the like.
A paint such as a silicon alkyd resin, a urethane resin, a silicone acrylic resin, or a fluororesin can be used.

[0044]

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.

Epoxy resin coating composition for primer
Preparation Example 1 "Epiclon EXA-7115" (Note 1) 150
, "Epiclon EXA-7120" (Note 2) 10 copies, "A
Solvent ”(20 parts) (Note 3) were sequentially charged, mixed and stirred, and this was used as a main ingredient. Thereafter, 30 parts of meta-xylylenediamine as a curing agent was added to the base material, mixed and stirred to obtain a coating composition. This coating composition was used within 6 hours. (Note 1) "Epiclon EXA-7115": trade name, manufactured by Dainippon Ink and Chemicals, Inc., alkylphenol-modified bisphenol A resin, viscosity 2400 mPa · s
(25 ° C.), and used as a 60% solid content organic solvent solution of this resin. The composition of the organic solvent is an aliphatic hydrocarbon solvent. (Note 2) “Epiclon EXA-7120”: trade name, alkyl diphenol type liquid epoxy resin, manufactured by Dainippon Ink and Chemicals, Inc., viscosity 1,600 mPa · s (25
C), and in the above formula (1), each of the two Rs is t
-Having a structure that is a butyl group. (Note 3) "A Solvent": manufactured by Nippon Oil Co., Ltd., trade name, mineral spirit Examples 2 to 9 and Comparative Examples 1 to 4 In Example 1, the composition was as shown in Tables 1 and 2. Other than the above, the same operation as in Example 1 was performed to obtain each coating composition. The coating composition was used within 6 hours. Note that (Note 4) to (Note 9) in Tables 1 and 2 are as follows. (Note 4) “YD-118”: Bisphenol A type liquid epoxy resin, manufactured by Toto Kasei Co., Ltd., having a viscosity of 1,000 mPa ·
s (25 ° C.). (Note 5) “Epicoat 828”: a bisphenol A type liquid epoxy resin manufactured by Yuka Shell Epoxy Co., Ltd., having a viscosity of 13,500 mPa · s (25 ° C.). (Note 6) Curing agent A: Ketimine compound of 1,3-aminomethylcyclohexane. It has a viscosity of 500 mPa · s (25 ° C.). (Note 7) Curing agent B: Ketimine compound of meta-xylylenediamine. It has a viscosity of 500 mPa · s (25 ° C.). (Note 8) Curing agent C: Ketimine compound of an adduct of meta-xylylenediamine and “Epicoat 828”. Viscosity 450
It has 0 mPa · s (25 ° C.). (Note 9) “EPICLON 703”: a product name, monoglycidyl ether, manufactured by Dainippon Ink and Chemicals, Inc.

[0046]

[Table 1]

[0047]

[Table 2]

Performance Test Each coating composition obtained as described above was subjected to the following performance tests. Table 3 shows the results. (* 1) Drying property: each coating composition was applied on a tin plate with a film applicator having a gap of 200 μm, and the temperature was 20
It was left in an atmosphere at a temperature of 65 ° C. and a humidity of 65% RH, and the time required for the coating film surface to reach a semi-cured state was evaluated by finger touch. The evaluation was based on the following criteria.

◎: Less than 8 hours ○: 8 hours or more and less than 16 hours Δ: 16 hours or more and less than 24 hours ×: 24 hours or more (* 2) Suitable for old coating film: Acrylic resin-based composite on flexible plate (slate) Layer finish coating material A top coat "Allestyle Top S" (manufactured by Kansai Paint Co., Ltd.) is applied, cured for 7 days, and then each coating composition is brush-coated thereon so as to be 0.2 kg / m ² . After curing for one day in an atmosphere at a temperature of 20 ° C. and a humidity of 65% RH, the same paint composition was further brushed thereon at 0.2 kg / m ² to obtain a temperature of 2 kg / m 2.
After curing for 1 day in an atmosphere of 0 ° C. and 65% RH,
The coating was evaluated for shrinkage. The evaluation was based on the following criteria.

：: No abnormality (not considered) ×: Slight (* 3) Penetration reinforcing property: The coating amount of each coating composition was applied to a calcical plate (specific gravity: 0.8) so that the coating amount was 0.2 kg / m ^2. Each coated plate was prepared by brush coating and curing for 7 days in an atmosphere at a temperature of 20 ° C. and a humidity of 65% RH.

(1) Penetration: Each coated plate was cut, and the cut surface was immersed in aqueous red ink to evaluate the penetration depth of each coating composition into the substrate. The evaluation was based on the following criteria.

◎: 200 μm or more ○: 100 μm or more and less than 200 μm Δ: 50 μm or more and less than 100 μm ×: less than 50 μm (2) Reinforcement: An X-cut cellotape (registered trademark) adhesion test was performed on each coated plate to obtain a substrate. The reinforcing properties were evaluated. The evaluation was based on the following criteria.

○: No peeling Δ: Peeling ×: Destruction of base material (* 4) Suitability for inorganic building materials: Each coating composition was applied to a flexible board with a brush so as to have an application amount of 0.2 kg / m ² .
After curing for 7 days in an atmosphere at a temperature of 20 ° C. and a humidity of 65% RH, the adhesiveness was evaluated by an X-cut cellophane tape adhesion test one day after immersion in water for 3 days and pulling up. The evaluation was based on the following criteria.

○: No peeling Δ: Partial peeling ×: Significant peeling (* 5) Sealing material bleed prevention function: One-part urethane sealing material is applied to half of the surface of the flexible plate.
After curing for 7 days, each coating composition was brush-coated on the sealing-coated surface (referred to as part a) and the other half of the flexible board surface (referred to as part b) so that the coating amount was 0.2 kg / m ² . After drying for one day, add “Sera M Retane white”
(Acrylic urethane resin paint, manufactured by Kansai Paint Co., Ltd.) was applied and cured in an atmosphere at a temperature of 20 ° C. and a humidity of 65% RH for 7 days, and then exposed outdoors for 3 months. A three months later
And the difference between the stains on the surface of part b was evaluated by ΔL value (color difference). The evaluation was based on the following criteria.

：: ΔL is 0 or more and less than 1.5, Δ: ΔL is 1.5 or more and less than 3.0 ×: ΔL is 3.0 or more

[0056]

[Table 3]

Coating Example 10 The coating composition of Example 1 was applied as a primer to a flexible board (slate) with a brush so as to have a coating amount of 0.2 kg / m ^2, and dried for one day. (Kansai Paint Co., Ltd., solvent type acrylic urethane resin paint) is applied by a brush so as to have an application amount of 0.12 kg / m ^2, and cured for 7 days in an atmosphere of a temperature of 20 ° C. and a humidity of 65% RH, and the coated plate I got

Example 11 and Comparative Example 5 The same operation as in Example 10 was carried out, except that the primer and the type of overcoat paint in Example 10 were changed as shown in Table 4, to obtain each coated plate. (Note 10) in Table 4 is as follows. (Note 10) “Aqualetan”: water-based acrylic urethane resin paint manufactured by Kansai Paint Co., Ltd. Example 12 A flexible plate was brushed with the paint composition of Example 1 as a primer so as to have an application amount of 0.2 kg / m ^2. After drying for one day, the applied amount of “Holder GII” (Kansai Paint Co., Ltd., water-based microelastic base adjustment material) was 0.5 kg / m ^2.
And dried for one day, and then applied with a brush so that the amount of “Aqualetan” is 0.13 kg / m ^2, and cured in an atmosphere at a temperature of 20 ° C. and a humidity of 65% RH for 7 days. To obtain a painted plate.

Performance Test Each coating composition obtained as described above was subjected to the following performance tests. Table 4 shows the results. (* 6) Coating film appearance: The coating film surface was visually observed. The evaluation was based on the following criteria.

◎: The coating film has no defects such as cracks, glossiness, and peeling. ○: The coating film has slight cracking and glossiness. Δ: The coating film has cracking, glossiness, and peeling. ×: Coating A film in which remarkable cracks, glossiness, and peeling are observed (* 7) Adhesion: Adhesion to a topcoat film was evaluated by an X-cut cellophane tape test. The evaluation was based on the following criteria.

：: No peeling was observed at all. Δ: Peeling was observed at a part of the coating film of the cutter flaw. X: Peeling of the coating film was observed at more than 25%. (* 8) Hot / cold repetition test: JIS A -6909 According to the test method of “resistance by repeated action of heating and cooling”, 10
The state of the coated surface after the cycle was visually evaluated. The evaluation was based on the following criteria.

◎: No abnormality at all ○: Slight swelling and cracks are observed, but there is no practical problem. Δ: Swelling and cracking are observed ×: Marked swelling, cracking and peeling are observed

[0063]

According to the coating composition of the present invention, the liquid epoxy resin (B) can secure the penetration reinforcement into the material and the epoxy resin (A) can secure the film forming property. It can reinforce brittle and degraded surfaces such as surfaces, and form a coating film having excellent drying properties, suitability for top coating, and excellent adhesion. In addition, since the coating composition of the present invention uses a solvent that does not cause dissolution of the old coating film, it does not dissolve the old coating film even if it is applied over the old coating film. A coating film excellent in film performance such as film suitability can be formed.

[0064]

[Table 4]

Continued on front page F-term (reference) 4J036 AA05 AB00 AB01 AC01 AD01 AD08 AF01 AF06 AG04 AG07 AH07 AJ18 CA06 CA16 CA20 DC02 DC06 DC09 DC10 JA01 KA01 4J038 DB051 DB052 DB331 DB332 DB341 DB342 JA02 JA03 JB04 JB05 JB07 NA12 PC06 PC04 PC08

Claims (5)

[Claims] 1. An epoxy resin having a viscosity of not less than 2,000 mPa · s at 25 ° C. and soluble in the following organic solvent (D): (B) an epoxy resin having a viscosity of 2,2 m at 25 ° C. 00
An epoxy resin having a viscosity of less than 0 mPa · s, and a liquid epoxy resin soluble in the following organic solvent (D), an amine-based curing agent, and a coating material containing an organic solvent (D),
The organic solvent (D) is an aliphatic hydrocarbon solvent and has a boiling point of 14.
An epoxy resin-based coating composition characterized in that the organic solvent (D) contains at least 80% by weight of a hydrocarbon solvent selected from aromatic hydrocarbon solvents having a boiling point of 8 ° C. or higher. 2. An epoxy resin (A) comprising bisphenol A
The epoxy resin-based coating composition according to claim 1, wherein the modified epoxy resin is a modified epoxy resin obtained by modifying a type epoxy resin with an alkylphenol or / and a fatty acid. 3. The liquid epoxy resin (B) has the following formula (1): ## STR1 ## (Wherein, R represents an alkyl group having 1 to 8 carbon atoms, and n represents 0)
The epoxy resin-based coating composition according to claim 1, wherein the composition comprises a compound represented by the formula (1) to (2). 4. The use ratio of the epoxy resin (A) and the liquid epoxy resin (B) is (A) / (B) = 90 /
The epoxy resin-based coating composition according to claim 1, wherein the ratio is 10 to 30/70. 5. The coated surface has (A) a viscosity of 2,000 at 25 ° C.
An epoxy resin having a viscosity of 25 ° C., which is an epoxy resin having a viscosity of 0 mPa · s or more and being soluble in the following organic solvent (D).
A liquid epoxy resin which is less than 2,000 mPa · s and is soluble in the following organic solvent (D):
A paint containing (C) an amine-based curing agent and (D) an organic solvent, wherein the organic solvent (D) is selected from an aliphatic hydrocarbon-based solvent and a high-boiling aromatic hydrocarbon-based solvent having a boiling point of 148 ° C. or higher. Hydrocarbon solvent in the organic solvent (D).
A coating method comprising applying an epoxy resin-based coating composition characterized by containing 0% by weight or more, and further applying a top coating.