JP6158971B1 - Coating composition, coating film forming method, article manufacturing method and article - Google Patents

Abstract

Disclosed is a coating composition capable of forming a coating film having excellent ethanol resistance even under low-temperature curing conditions. To provide an article having a coating film excellent in ethanol resistance. To provide a method for forming a coating film capable of forming a coating film excellent in ethanol resistance even under low temperature curing conditions. To provide a method for producing an article having a coating film excellent in ethanol resistance. SOLUTION: (A) an acrylic-modified epoxy resin and (B) an oxazoline-based curing agent, (A) comprising (a1) an epoxy resin and (a2) an acidic group-containing radical polymerizable unsaturated compound. A coating composition having a mass ratio (a1: a2) of 95: 5 to 60:40. An article having a coating film formed using a coating composition. A method for forming a coating film or a method for producing an article, comprising: a step of forming a coating film by applying a coating composition on an object to be coated; and a step of drying or heating the coating film to form a coating film. [Selection figure] None

Description

  The present invention relates to a coating composition, a method for forming a coating film, a method for producing an article, and an article.

  In a wide range of industrial products such as home appliances, electronic equipment, decorative products, furniture, and building materials, coatings are formed on the surfaces of these products and parts for the purpose of protecting and decorating the products and parts. Generally done. Further, in recent years, due to environmental considerations, a shift from organic solvent-based materials to water-based materials has been attempted. Furthermore, various water-based materials that can be formed at a relatively low temperature have been proposed as coating film forming materials for plastic substrates that are relatively weak against heat.

  For example, Patent Document 1 discloses an aqueous dispersion of an acrylic-modified epoxy resin and a modified bisphenol A-type epoxy resin, which can provide a coating film having excellent properties from room temperature to forced drying conditions and has excellent paint stability. An aqueous coating composition containing is disclosed.

JP 2002-256209 A

  However, the aqueous coating composition of Patent Document 1 can be dried by heating at a low temperature such as 20 minutes at 80 ° C., but is said to be the most severe in physical properties, particularly solvent resistance, of the formed coating film. There was room for improvement in ethanol resistance.

  Ethanol is known as a detergent for industrial products. In general, an organic solvent has a tendency to dissolve and swell a coating film, and particularly ethanol is known to have a large tendency. For this reason, durability against ethanol is also required for a coating film formed on the surface of an industrial product.

  Also, in recent years, plastic substrates that are relatively resistant to heat are often used for housings of electrical equipment such as home appliances. However, when heat curing (baking) is performed at a higher temperature of about 150 ° C., paint Options for articles that can be coated with the composition to form a coating are narrowed.

  Then, an object of this invention is to provide the coating composition which can form the coating film excellent in ethanol resistance also under low temperature curing conditions. Another object of the present invention is to provide an article having a coating film excellent in ethanol resistance. Another object of the present invention is to provide a coating film forming method capable of forming a coating film having excellent ethanol resistance even under low temperature curing conditions. Moreover, an object of this invention is to provide the manufacturing method of the articles | goods which have a coating film excellent in ethanol resistance.

The coating composition according to the present invention comprises:
(A) an acrylic-modified epoxy resin;
(B) an oxazoline-based curing agent;
Including
(A)
(A1) an epoxy resin;
(A2) a radically polymerizable unsaturated compound including an acidic group-containing radically polymerizable unsaturated compound;
The reaction product of
The mass ratio (a1: a2) between (a1) and (a2) is 95: 5-60: 40,
It is a coating composition. With this configuration, a coating film excellent in ethanol resistance can be formed even under low temperature curing conditions.

  In one embodiment of the coating composition according to the present invention, the number average molecular weight of (A) is 3,000 to 30,000.

In one embodiment of the coating composition according to the present invention, (a1) is an aromatic epoxy resin,
The acidic group-containing radical polymerizable unsaturated compound includes a carboxyl group-containing radical polymerizable unsaturated compound.

  In one embodiment of the coating composition according to the present invention, (a2) does not contain a nitrogen atom.

  The article according to the present invention has a coating film formed using any of the coating compositions described above. With this configuration, the article is excellent in ethanol resistance.

The method for forming a coating film according to the present invention includes:
A step of applying a coating composition according to any of the above to an object to form a film;
Drying or heating the coating to form a coating;
A method for forming a coating film. With this configuration, a coating film excellent in ethanol resistance can be formed even under low temperature curing conditions.

The method for producing an article according to the present invention includes:
A step of applying a coating composition according to any of the above to an object to form a film;
Drying or heating the coating to form a coating;
The manufacturing method of articles | goods containing this. With this configuration, an article having a coating film excellent in ethanol resistance can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the coating composition which can form the coating film excellent in ethanol resistance under low temperature curing conditions can be provided. Moreover, according to this invention, the articles | goods which have a coating film excellent in ethanol resistance can be provided. Moreover, according to this invention, the formation method of the coating film which can form the coating film excellent in ethanol resistance under low temperature curing conditions can be provided. Moreover, according to this invention, the manufacturing method of the articles | goods which have a coating film excellent in ethanol resistance can be provided.

  Hereinafter, embodiments of the present invention will be described. These descriptions are intended to exemplify the present invention and do not limit the present invention in any way.

  In the present invention, “even under low temperature curing conditions” means a temperature condition equal to or lower than about 150 ° C., which is performed in a painting process of a factory production line for industrial products, unless otherwise specified.

  In the present invention, the (meth) acryloyl group means one or more selected from the group consisting of an acryloyl group, a methacryloyl group, and a combination thereof.

  In the present invention, the number average molecular weight is calculated as a standard polystyrene equivalent value by gel permeation chromatography (GPC).

  In the present invention, the article to be coated means an object before the coating composition is applied, and the article is an article in which the coating composition is applied to the article to be coated and a coating film is formed on the article to be coated. The thing which has the coating film formed using the coating composition is meant.

  In the present invention, application means an action of applying a coating composition to an object to be coated, and painting means a general term for an action of forming a coating film on the object to be coated.

  In the present invention, two or more embodiments can be arbitrarily combined.

(Coating composition)
The coating composition according to the present invention comprises:
(A) an acrylic-modified epoxy resin;
(B) an oxazoline-based curing agent;
Including
(A)
(A1) an epoxy resin;
(A2) a radically polymerizable unsaturated compound including an acidic group-containing radically polymerizable unsaturated compound;
The reaction product of
The mass ratio (a1: a2) between (a1) and (a2) is 95: 5-60: 40,
It is a coating composition. With this configuration, a coating film excellent in ethanol resistance can be formed.

  The coating composition according to the present invention can be cured even at a low temperature of about 80 ° C. and can form a coating film excellent in ethanol resistance. Therefore, it can be suitably used for a plastic substrate.

  In this specification, (A) an acrylic-modified epoxy resin, (B) an oxazoline-based curing agent, (a1) an epoxy resin, and (a2) a radically polymerizable unsaturated compound including an acidic group-containing radically polymerizable unsaturated compound, , (A), (B), (a1), (a2) may be abbreviated.

<(A) Acrylic modified epoxy resin>
(A) is an acrylic-modified epoxy resin. The acrylic-modified epoxy resin is a reaction product of (a1) an epoxy resin described later and (a2) a radically polymerizable unsaturated compound including an acidic group-containing radically polymerizable unsaturated compound. That is, the (A) acrylic-modified epoxy resin in the present invention is a resin obtained by modifying (a1) an epoxy resin with an acidic group-containing radically polymerizable unsaturated compound. The component (A) forms a coating film excellent in ethanol resistance even under low temperature curing conditions by a curing reaction with the (B) oxazoline-based curing agent described later.

<(A1) Epoxy resin>
(A1) The epoxy resin is not particularly limited, and a known epoxy resin can be used. Examples thereof include aromatic epoxy resins such as bisphenol type epoxy resins, novolak type epoxy resins, biphenyl type epoxy resins, and naphthalene type epoxy resins; aliphatic epoxy resins such as dicyclopentadiene type epoxy resins.

  Examples of bisphenol type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD type epoxy resins, diglycidyl ethers of alkylene oxide adducts of the above bisphenol type epoxy resins, and the above. Examples thereof include hydrogenated bisphenol type epoxy resins obtained by adding hydrogen to bisphenol type epoxy resins.

  Examples of the novolak type epoxy resin include phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, and the like.

  Examples of the biphenyl type epoxy resin, naphthalene type epoxy resin, and dicyclopentadiene type epoxy resin include resins in which one or two or more glycidyl ether groups are substituted at an arbitrary position of biphenyl, naphthalene, or dicyclopentadiene.

  Examples of the aliphatic epoxy resin include glycidyl ethers of polyhydric alcohols in addition to the above-mentioned dicyclopentadiene type epoxy resin.

  The preparation method of (a1) is not specifically limited, A well-known method can be used. For example, the bisphenol A type epoxy resin can be obtained by condensing a halogen-substituted product of bisphenol A with epichlorohydrin or β-methylepihalohydrin.

  (A1) may use a commercial item. Commercially available products include, for example, jER (registered trademark) 1001, 1004, 1007, 1010 manufactured by Mitsubishi Chemical Corporation; YD-014U, 017, 019, 020H, 128, YDF-2004, YP-50S manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. EPICLON (registered trademark) 850, 1050, 3050, 4050, 7050, HM-091, HM-101 manufactured by DIC; DER-661, DER-664 manufactured by The Dow Chemical Company;

  In one embodiment, (a1) is an aromatic epoxy resin. In another embodiment, (a1) is a bisphenol type epoxy resin.

  (A1) may be used alone or in combination of two or more.

<(A2) Radical polymerizable unsaturated compound including acidic group-containing radical polymerizable unsaturated compound>
(A2) is a radically polymerizable unsaturated compound including an acidic group-containing radically polymerizable unsaturated compound. That is, (a2) includes at least an acidic group-containing radically polymerizable unsaturated compound, and in addition to this, (a2) may further include or include a radically polymerizable unsaturated compound having no acidic group. It does not have to be. As (a2), a known acidic group-containing radical polymerizable unsaturated compound or a radical polymerizable unsaturated compound having no acidic group can be used.

Examples of the acidic group of the acidic group-containing radically polymerizable unsaturated compound include a carboxyl group, a sulfonic acid group (—SO ₃ H), and a phosphoric acid group (H ₂ PO ₄ —).

  Examples of the carboxyl group-containing radical polymerizable unsaturated compound include compounds containing a carboxyl group such as acrylic acid and methacrylic acid and a (meth) acryloyl group; maleic acid, itaconic acid, monoethyl maleate, monobutyl maleate, itacone Examples thereof include compounds containing at least one carboxyl group and an ethylenically unsaturated bond such as monoethyl acid and monobutyl itaconate.

  Examples of the sulfonic acid group-containing radical polymerizable unsaturated compound include acrylamide t-butylsulfonic acid, 2-acrylamido-2-methylsulfonic acid, acrylic acid 3-sulfopropyl ester, methacrylic acid 3-sulfopropyl ester, and itaconic acid. And bis (3-sulfopropyl) ester.

Examples of the phosphate group-containing radically polymerizable unsaturated compound include compounds represented by the general formula CH ₂ ═C (R ¹ ) COO— (CH ₂ CHR ² O) _n —P (═O) (OH) ₂ . (Wherein R ¹ is H or CH ₃ , R ² is H, CH ₃ or CHCl, and n is 1 to 6).

  Examples of the radical polymerizable unsaturated compound having no acidic group include ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-methacrylic acid 2- Alkyl esters of α, β-ethylenically unsaturated aliphatic carboxylic acids such as ethylhexyl and N, N-dimethylaminoethyl acrylate; α, β-ethylenically unsaturated aliphatic carboxylic acids such as glycidyl acrylate and glycidyl methacrylate Glycidyl ester; vinyl ester of saturated aliphatic carboxylic acid such as vinyl acetate and vinyl propionate; aromatic vinyl compound such as styrene, α-methylstyrene and vinyltoluene; 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, Acrylic acid 2-hydride Α, β-ethylenically unsaturated aliphatic carboxylic acid having a hydroxyl group such as roxypropyl, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, or the reaction product of 2-hydroxyethyl methacrylate and ε-caprolaclone Examples include alkyl esters of acids.

  In addition, examples of the radical polymerizable unsaturated compound having no acidic group include amides such as acrylamide, methacrylamide, N-methylol acrylamide, N-methoxybutyl acrylamide, diacetone acrylamide, and N, N-dimethylaminopropyl acrylamide. And an ethylenically unsaturated compound having a group. In one embodiment, the number of carbon atoms in the molecule of the ethylenically unsaturated compound having an amide group is 12 or less.

  The number of carbon atoms in (a2) is not particularly limited. In one embodiment, the acidic group-containing radically polymerizable unsaturated compound has 6 or less carbon atoms. By making the number of carbon atoms 6 or less, (A) can be easily made aqueous.

  In one embodiment, (a2) does not contain a nitrogen atom. When (a2) does not contain a nitrogen atom, ethanol resistance can be further improved. In another embodiment, (a2) does not contain an epoxy group.

  In one embodiment, the acidic group-containing radically polymerizable unsaturated compound includes a carboxyl group-containing radically polymerizable unsaturated compound. In another embodiment, the acidic group-containing radically polymerizable unsaturated compound is a carboxyl group-containing radically polymerizable unsaturated compound.

  In one embodiment of the coating composition according to the present invention, (a1) is an aromatic epoxy resin, and the acidic group-containing radical polymerizable unsaturated compound contains a carboxyl group-containing radical polymerizable unsaturated compound.

  In one embodiment, (a2) includes an acidic group-containing radically polymerizable unsaturated compound and a radically polymerizable unsaturated compound having no acidic group.

  When (a2) contains an acidic group-containing radically polymerizable unsaturated compound and a radically polymerizable unsaturated compound having no acidic group, the acidic group-containing radically polymerizable unsaturated compound with respect to the total mass of (a2) What is necessary is just to adjust the ratio of mass suitably. In one embodiment, the ratio of the mass of the acidic group-containing radically polymerizable unsaturated compound to the total mass of (a2) is 10% by mass or more, and in another embodiment, 50% by mass or more. In one embodiment, it is 60% by mass or more, in one embodiment, 100% by mass or less, in another embodiment, 80% by mass or less, and in another embodiment, 70% by mass or less. .

  In (A), the mass ratio (a1: a2) between (a1) and (a2) is 95: 5-60: 40, where the total mass of (a1) and (a2) is 100. If the mass ratio of (a2) is less than 5, the resulting (A) acrylic-modified epoxy resin may not be dispersed in water. Moreover, when the mass ratio of (a2) exceeds 40, there exists a possibility that the ethanol resistance of the coating film obtained may be inferior. The mass ratio (a1: a2) is, in one embodiment, the mass ratio of (a2) is 10 or more, in another embodiment, 35 or less, and in another embodiment, 30 or less.

  (A2) may be used alone or in combination of two or more.

  The preparation method of (A) is not specifically limited, A well-known method can be used. For example, (A) can be obtained by polymerizing (a2) in the presence of (a1). Moreover, you may use a well-known initiator at the time of the superposition | polymerization.

  When an initiator is used, it is considered that (A) is obtained as follows, but the present invention is not limited to this. First, the initiator acts on (a2) to generate radicals, and at the same time, hydrogen abstraction occurs from the methine or methylene group in (a1). Furthermore, it is considered that the radicals generated by the hydrogen abstraction of (a1) recombine with each other to form a dimer of (a1), and finally (A) is obtained. Thus, in order to obtain (A), it is preferable to use an initiator having a crosslinking efficiency of 28% or more. Here, the “crosslinking efficiency” of the initiator is defined by the molar amount of the dimer produced per mole of the initiator to be added, and is expressed as a percentage.

  Examples of the initiator having a crosslinking efficiency of 28% or more include benzoyl peroxide, t-butylperoxybenzoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxytrimethylhexanoate, t- Octylperoxybenzoate, t-butylperoxyisopropyl carbonate, t-butylperoxystearyl carbonate, t-amylperbenzoate, dicumyl peroxide, t-butylcumyl peroxide, dimethyldi-t-butylhexane, bis (t- And organic peroxides such as butylperoxyisopropyl) benzene, di-t-butyl peroxide, and dimethyl-di-t-butylhexyne.

  The molecular weight of (A) is not particularly limited and may be adjusted as appropriate. In one embodiment, the number average molecular weight of (A) is 3,000 or more, in another embodiment 5,000 or more, and in another embodiment 7,000 or more. In one embodiment, the number average molecular weight of (A) is 30,000 or less, in another embodiment, 25,000 or less, and in another embodiment, 20,000 or less. Moreover, in one Embodiment, the number average molecular weight of (A) is 3,000-30,000. When the number average molecular weight of (A) is 3,000 or more, the resulting coating film has improved alcohol resistance and water resistance, and when it is 30,000 or less, paint stability is improved.

  The acid value of (A) is not particularly limited, and may be adjusted as appropriate. For example, it can be 10-70, 15-65, or 20-60, 25-55, or 30-50. Preferably it is 15-65, More preferably, it is 20-40. When the acid value of (A) is 10 or more, the coating stability is improved, and when the acid value of (A) is 70 or less, the alcohol resistance and water resistance of the resulting coating film are increased. In addition, the acid value in this specification represents a solid content acid value, respectively, and can be measured by the method described in JIS K0070.

  The ratio of the number of moles of the acidic group (A) and the number of moles (B) described later is not particularly limited, and may be adjusted as appropriate. For example, it can be 10: 1 to 10:30, 10: 5 to 10:18. By making the ratio of the number of moles within the above range, the alcohol resistance and water resistance of the resulting coating film are increased.

  In one embodiment, (A) does not contain a nitrogen atom in its backbone. Since (A) does not contain a nitrogen atom in its main chain, ethanol resistance can be further improved.

  (A) usually has an acidic group derived from an acidic group-containing radically polymerizable unsaturated compound in its side chain portion. In one embodiment, in order to make (A) aqueous, some or all of the acidic groups contained in the side chain of (A) are neutralized with a basic substance such as organic amines or inorganic amines. It may be used as a salt.

  The organic amines are not particularly limited, and known amines can be used. Examples thereof include amine compounds such as tributylamine, triethylamine, monoethanolamine, dimethylethanolamine, methylethanolamine, morpholine, N-methylmorpholine. In one embodiment, the organic amines are tertiary amines such as tributylamine, triethylamine, dimethylethanolamine, N-methylmorpholine.

  Inorganic amines are not particularly limited, and known amines can be used. An example is ammonia.

  The amount of basic substances such as organic amines used is not particularly limited, and may be appropriately adjusted so that (A) can be made aqueous or dispersed in water. For example, it can be set to an amount corresponding to 30 to 200% of the acidic group equivalent.

  Aqueousization of (A) may be performed simultaneously with neutralization, for example, by adding a basic substance and water to (A), or by adding (A) to water containing a basic substance, Neutralization and aqueous formation of (A) can be performed simultaneously. In one embodiment, optionally, after completion of the aqueous treatment, the solvent contained in the system is distilled off under reduced pressure. In this way, the aqueous dispersion (A) can be obtained.

  (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

<(B) Oxazoline-based curing agent>
(B) is an oxazoline-based curing agent. (B) is a compound having an oxazoline group, and examples of the oxazoline group include a 2-oxazoline group. The number of oxazoline groups possessed by (B) is not particularly limited, and may be appropriately selected. In one embodiment, (B) has two or more oxazoline groups.

  (B) can use a well-known oxazoline type hardening | curing agent. Examples of (B) include 2,2′-bis (2-oxazoline), two 2-oxazoline groups, or 4,4-dimethyl-2-oxazoline group in which two 2-oxazoline groups are directly bonded. However, the compound couple | bonded by the bivalent hydrocarbon group is mentioned. Examples of the divalent hydrocarbon group include an aliphatic hydrocarbon group having 1 to 8 carbon atoms such as methylene, trimethylene and cyclohexylene, and an aromatic hydrocarbon group such as phenylene. For example, when the divalent hydrocarbon group is methylene, (B) is 2,2'-methylenebis (2-oxazoline). Other examples of (B) include bis- (2-oxazolinylcyclohexane) sulfide and bis- (2-oxazolinyl norbornane) sulfide.

  The preparation method of (B) mentioned above is not specifically limited, A well-known method can be used. For example, a method of dehydrating cyclization by heating amide alcohol in the presence of a catalyst, a method of synthesizing from alkanolamine and nitrile, or a method of synthesizing from alkanolamine and carboxylic acid can be mentioned.

  The form of (B) is not particularly limited, and any of solid, organic solvent or water solution, dispersion, and emulsion may be used.

  (B) may use a commercial item. Examples of commercially available products (B) include Epocross (registered trademark) such as EPOCROSS (registered trademark) WS-300, WS-500, WS-700, K-2010E, K-2020E, K-2030E manufactured by Nippon Shokubai Co., Ltd. ) Series.

  (B) may be used individually by 1 type, and may be used in combination of 2 or more type.

  In addition to (A) and (B), the coating composition may be used in coating compositions. (C) Film-forming aid (solvent); Film-forming resin other than (A); Pigment; Sand, etc. Drying delay aids; viscosity modifiers; antiseptics; fungicides; antiseptics; antifoaming agents; light stabilizers; antioxidants; UV absorbers; pH adjusters; You may go out. Hereinafter, examples of the coating film-forming resin other than (C) and (A) will be described.

  (C) is a film-forming aid (solvent). (C) has the effect of further enhancing the ethanol resistance of the coating film obtained from the coating composition.

  As (C), a known film-forming aid (solvent) used in the coating composition may be used. For example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol; benzyl alcohol, 2-phenylethanol, 3-phenyl-1-propanol, 4-methoxybenzyl alcohol; phenyl glycol, benzyl glycol Glycol ether compounds such as diethylene glycol dibutyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, butylpropylene diglycol, tripropylene glycol monobutyl ether; dibutyl phthalate, di-2-ethylhexyl phthalate, Diisononyl phthalate, diisodecyl phthalate, diheptyl phthalate, di-n- Kuchirufutareto, butyl benzyl phthalate, ethyl phthalyl ethyl glycolate, di-2-ethylhexyl adipate, carboxylate ester-based compounds such as dibutyl diglycol adipate; methyl isobutyl ketone, methyl ethyl ketone and methyl pentyl ketone.

  (C) may be used alone or in combination of two or more.

  Content of (C) is not specifically limited, What is necessary is just to adjust suitably considering desired performance, applicability | paintability, drying property, etc.

  The coating composition may or may not contain a known film-forming resin other than (A). Examples of such a film-forming resin include an acrylic resin, a polyester resin, a urethane resin, a butadiene resin, a phenol resin, and a xylene resin.

  When using a film-forming resin other than (A), the ratio of the film-forming resin other than (A) is 20% by mass or less in one embodiment with respect to the mass of the resin component contained in the coating composition. In another embodiment, it is 10% by mass or less.

  The form of the coating composition is not particularly limited and can be appropriately selected. For example, the form of the coating composition may be either liquid or paste.

  In one embodiment, the coating composition can also be suitably used as an electrodeposition coating composition, particularly an anionic electrodeposition coating composition.

  The preparation method of a coating composition is not specifically limited, A well-known method can be used, For example, what is necessary is just to mix the component mentioned above in arbitrary orders.

  When the coating composition contains a pigment, in order to facilitate the dispersion of the pigment, the pigment may be prepared in the form of an anionic pigment dispersion paste in which the pigment is previously dispersed in an anionic pigment dispersant.

  The preparation method of an anionic pigment dispersion paste is not specifically limited, A well-known method can be selected suitably and can be used. For example, after mixing an anionic pigment dispersant, a pigment, optionally a basic substance, and optionally an aqueous medium, until the particle size of the pigment in the mixture reaches a predetermined uniform particle size, It can be obtained by dispersing using a known dispersing device such as a ball mill or a sand grind mill.

  As the anionic pigment dispersant, a known anionic dispersant can be appropriately selected and used. For example, the modified acrylic resin etc. which are prepared using acrylic acid ester, acrylic acid, an azonitrile compound, etc. are mentioned.

  The pigment is not particularly limited, and pigments such as inorganic pigments and organic pigments used for known electrodeposition coating can be selected and used.

  As inorganic pigments, for example, colored pigments such as titanium oxide, iron oxide, calcined pigment, carbon black and bengara; extender pigments such as kaolin, talc, aluminum silicate, calcium carbonate, mica, clay and silica; zinc phosphate, phosphorus Protection of iron oxide, aluminum phosphate, calcium phosphate, zinc phosphite, zinc cyanide, zinc oxide, aluminum tripolyphosphate, zinc molybdate, aluminum molybdate, calcium molybdate, aluminum phosphomolybdate, zinc phosphomolybdate, etc. Examples include rust pigments.

  Examples of organic pigments include phthalocyanine blue, phthalocyanine green, monoazo yellow, disazo yellow, benzimidazolone yellow, quinacridone red, monoazo red, boriazo red, and berylene red.

  A pigment may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of basic substances include diethylamine, ethylethanolamine, diethanolamine, monoethanolamine, monopropanolamine, isopropanolamine, ethylaminoethylamine, hydroxyethylamine, diethylenetriamine, triethylamine and other organic amines; ammonia and other inorganic amines; Examples include alkali metal hydroxides such as sodium and potassium hydroxide.

  Examples of the aqueous medium include water or a mixture of water and an organic solvent such as ethanol. Ion exchange water may be used as water.

  Usually, an anionic pigment dispersion paste is prepared by solid content 35-70 mass%, or 40-65 mass%.

<Electrodeposition coating composition>
The method for preparing the anionic electrodeposition coating composition can be any known method for preparing an electrodeposition coating composition, except for using (A) and (B) described above, and is not particularly limited. For example, it can be prepared by dispersing (A), (B), optionally an anionic pigment dispersion paste, and optionally a basic substance in an aqueous medium.

  The amount of the basic substance may be, for example, an amount sufficient to neutralize 30% or more, 200% or less, or 50 to 120% with respect to the acidic group equivalent of (A). Moreover, you may adjust the pH of an anionic electrodeposition coating-material composition using a basic substance. The pH of the anionic electrodeposition coating composition is 6.0 to 9.0 in one embodiment, and 7.0 to 8.5 in another embodiment.

(Formation method of coating film)
The method for forming a coating film according to the present invention includes:
A step of applying a coating composition according to any of the above to an object to form a film;
Drying or heating the coating to form a coating;
A method for forming a coating film. With this configuration, a coating film excellent in ethanol resistance can be formed even under low temperature curing conditions.

  The coating composition is the above-described coating composition according to the present invention. The coating composition may be the electrodeposition coating composition or the anionic electrodeposition coating composition described above.

  The article to be coated is not particularly limited and can be a known article to be coated.

  Examples of the objects to be coated include household electrical appliances (household electrical appliances) and their housings, electrical devices other than homes, and housings, ornaments, furniture, building materials, vehicles, and their bodies, ships, and airplanes. Can be mentioned. In one embodiment, the object to be coated is a housing of a home appliance. In another embodiment, the article to be coated is plastic. In the present invention, the casing is a concept including a case, a housing, and an enclosure.

  It does not specifically limit as a material of a to-be-coated object, It can be set as the material of a well-known to-be-coated object. For example, a metal, a plastic, etc. can be mentioned.

  It does not specifically limit as a metal, For example, aluminum, iron, a galvanized steel plate, an aluminum galvanized steel plate, stainless steel, tinplate etc. can be mentioned.

  Examples of the plastic include acrylic, polyvinyl chloride, polycarbonate, ABS, polyethylene terephthalate, and polyolefin.

  The coating method of a coating composition is not specifically limited, A well-known coating method can be used. For example, coating methods such as electrodeposition, dipping, brush, roller, roll coater, air spray, airless spray, curtain flow coater, roller curtain coater, and die coater can be used.

  The region where the coating composition is applied to the object to be coated is not particularly limited, and may be appropriately selected and applied to a part or all of the object to be coated.

  The thickness of the coating is not particularly limited, and may be appropriately adjusted according to the thickness of the coating obtained by drying or heating, the use, the object to be coated, the desired performance, and the like. For example, the thickness of the coating film obtained by curing can be 5 to 20 μm or 7 to 12 μm.

  In the step of drying or heating the coating to form the coating, the drying or heating conditions (curing conditions) are not particularly limited, and known conditions can be used. For example, the temperature can be 30 ° C or higher, 70 ° C or higher, 80 ° C or higher, 100 ° C or higher, or 120 ° C or higher, 180 ° C or lower, 150 ° C or lower, 120 ° C or lower, 100 ° C or lower, or 90 ° C or lower. The curing time can be, for example, 30 seconds to 60 minutes. Moreover, when hardening temperature is low temperature, it is good also as 10 to 120 minutes or 10 to 60 minutes, for example. As described above, by using the coating composition according to the present invention, it can be cured even at a low temperature of about 80 ° C.

  In the method for forming a coating film according to the present invention, steps other than the steps described above may be included. For example, a pretreatment process such as surface treatment or plating of an object to be coated, a multiple coating film forming process such as intermediate coating to top coating, and the like may be included.

<Electrodeposition coating method>
The method of electrodeposition coating using the anion electrodeposition coating composition is not particularly limited, and a known electrodeposition coating method can be used. For example, a voltage of 1 to 400 V is usually applied between the object to be coated as the anode and the cathode. The temperature of the bath liquid of the anion electrodeposition coating composition during electrodeposition coating can be, for example, 10 to 45 ° C or 15 to 30 ° C.

  The electrodeposition coating process includes, for example, a step of immersing the object to be coated in the anion electrodeposition coating composition, and applying a voltage between the anode (object to be coated) and the cathode to form a film on the object to be coated. A step of depositing, a step of lifting the object to be coated from the anion electrodeposition coating composition, a step of washing the object to be washed with water, and a step of drying or baking the film to form a film.

  The coating object is not particularly limited, and a known electrodeposition coating object can be used. For example, an object to be coated similar to the method for forming the coating film can be used.

  What is necessary is just to adjust suitably the time to apply a voltage according to electrodeposition conditions, for example, can be 30 second-5 minutes.

  The conditions for drying or baking can be the same as the method for forming the coating film.

  The thickness of the coating film is not particularly limited, and may be appropriately adjusted according to the use, the object to be coated, the desired performance, and the like. For example, it can be 5 to 20 μm, or 7 to 12 μm.

(Product manufacturing method)
The method for producing an article according to the present invention includes:
A step of applying a coating composition according to any of the above to an object to form a film;
Drying or heating the coating to form a coating;
The manufacturing method of articles | goods containing this. With this configuration, an article having a coating film excellent in ethanol resistance can be obtained.

  The coating composition is the above-described coating composition according to the present invention. The coating composition may be the electrodeposition coating composition or the anionic electrodeposition coating composition described above.

  The article to be coated is not particularly limited and can be a known article to be coated. Examples of the type and material of the object to be coated include the type and material of the object described in the method for forming a coating film. In one embodiment, the object to be coated is a housing of a home appliance. In another embodiment, the article to be coated is plastic. The kind of article | item is not specifically limited, It is the same as the kind demonstrated by the below-mentioned article | item.

  The coating method of a coating composition is not specifically limited, The coating method demonstrated by the formation method of the said coating film is mentioned.

  The region where the coating composition is applied to the object to be coated is not particularly limited, and may be appropriately selected and applied to a part or all of the object to be coated.

  The thickness of the coating is not particularly limited, and is the same as the thickness of the coating described in the method for forming a coating.

  In the step of drying or heating the coating to form the coating, the drying or heating conditions (curing conditions) are not particularly limited, and known conditions can be used. For example, the temperature can be 30 ° C or higher, 70 ° C or higher, 80 ° C or higher, 100 ° C or higher, or 120 ° C or higher, 180 ° C or lower, 150 ° C or lower, 120 ° C or lower, 100 ° C or lower, or 90 ° C or lower. The curing time can be, for example, 30 seconds to 60 minutes. As described above, by using the coating composition according to the present invention, it can be cured even at a low temperature of about 80 ° C.

  In the method for manufacturing an article according to the present invention, steps other than the steps described above may be included. For example, a pretreatment process such as surface treatment or plating of an object to be coated, a multiple coating film forming process such as intermediate coating to top coating, and the like may be included.

(Goods)
The article according to the present invention has a coating film formed using the coating composition. Thereby, the article is excellent in ethanol resistance.

  The article is not particularly limited, and can be an article obtained by forming a coating film on a known article to be coated.

  Examples of the type and material of the object to be coated include the type and material of the object described in the method for forming a coating film. Accordingly, the article has a coating film formed by using the coating composition, and home appliances (household electrical appliances) and their housings, electrical devices other than household electrical appliances, and housings, ornaments, furniture, and building materials Vehicles and their bodies, ships, aircraft and the like. In one embodiment, the article is a housing for home appliances. In another embodiment, the article is plastic.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, these Examples aim at the illustration of this invention, and do not limit this invention at all. Unless otherwise specified, the blending amount means parts by mass.

The details of the materials used in the examples are as follows.
(A1) Epoxy resin 1: YP-50S (Bisphenol A type epoxy resin manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., number average molecular weight 14,000)
(A1) Epoxy resin 2: YD-020G (Bisphenol A type epoxy resin manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., number average molecular weight 8,000, epoxy equivalent 5,000)
(A2) Acid group-containing radical polymerizable unsaturated compound: methacrylic acid (a2) radical polymerizable unsaturated compound 1: ethyl acrylate (a2) radical polymerizable unsaturated compound 2: styrene comparison resin 1: acrylic resin (DIC Corporation) Barnock (registered trademark) WD-551 made by
Comparative resin 2: alkyd resin (Watersol (registered trademark) CD-520P manufactured by DIC)
(B) Oxazoline-based curing agent 1: Epocross (registered trademark) WS700 (an oxazoline group-containing polymer manufactured by Nippon Shokubai Co., Ltd.)
(B) Oxazoline-based curing agent 2: Epocross (registered trademark) WS500 (an oxazoline group-containing polymer manufactured by Nippon Shokubai Co., Ltd.)
(B) Oxazoline-based curing agent 3: Epocross (registered trademark) K-2030E (an oxazoline group-containing polymer manufactured by Nippon Shokubai Co., Ltd.)
Comparative curing agent 1: Block isocyanate compound (Baihijoule (registered trademark) VPLS2186 manufactured by Bayer)
Comparative curing agent 2: Melamine compound (Symel (registered trademark) 325 manufactured by Ornex Japan)
Comparative curing agent 3: Carbodiimide compound (Carbodilite (registered trademark) E-02 manufactured by Nisshinbo Chemical Co., Ltd.)

Example 1
Using the materials shown in Table 1, an aqueous dispersion of (A) an acrylic-modified epoxy resin was prepared by the procedure shown below, and then a coating composition was prepared.

((A) Preparation of acrylic-modified epoxy resin)
A reactor equipped with a heating device, a stirrer and a reflux condenser was charged with 45 parts by mass of (a1) YP-50S and 45 parts by mass of (a1) YD-020H. To the reactor, 15 parts by mass of butyl carbitol, 30 parts by mass of methyl isobutyl ketone and 60 parts by mass of methoxypropanol were added. Next, the mixture was heated to 120 ° C. while being stirred, and the bisphenol A type epoxy resin (a1) was dissolved. The solution of (a1) was cooled to 110 ° C. A mixture of (a2) consisting of (a2) 6 parts by mass of methacrylic acid, (a2) 2 parts by mass of ethyl acrylate, (a2) 2 parts by mass of styrene and 10 parts by mass of methyl isobutyl ketone was prepared. Moreover, the initiator solution which melt | dissolved 2 mass parts of benzoyl peroxide which is an initiator with 19 mass parts of methyl isobutyl ketone was prepared. To the solution of (a1), the mixture of (a2) and the initiator solution were dropped simultaneously from separate dropping funnels over 2 hours. After completion of the dropping, the solution was kept at 110 ° C. for 30 minutes. Next, a solution in which 0.2 part by mass of benzoyl peroxide was dissolved in 2 parts by mass of methyl isobutyl ketone was dropped into the solution over 30 minutes. Thereafter, the solution was further maintained at 110 ° C. for 3 hours to obtain (A) an acrylic-modified epoxy resin. The obtained (A) acrylic-modified epoxy resin had a non-volatile content of 43.8%, a solid content acid value of 39 mgKOH / g, and a number average molecular weight of 15,000. Furthermore, when this acrylic modified epoxy resin was cooled to 60 ° C., a solution containing 197 parts by mass of deionized water and 7.05 parts by mass of triethylamine as a basic substance was added dropwise over 2 hours. After completion of dropping, the temperature was kept at 60 ° C. for 30 minutes. Subsequently, the organic solvent was removed under reduced pressure to obtain an aqueous dispersion of (A) acrylic-modified epoxy resin. The obtained water dispersion had a nonvolatile content of 34.5%, a solid content acid value of 39 mgKOH / g, and a pH of 7.54.

(Preparation of coating composition)
In the formulation shown in Table 2, 70 parts by mass of deionized water and 5 parts by mass of (B) Epocross (registered trademark) WS700 were mixed with 25 parts by mass of the aqueous dispersion of (A) acrylic-modified epoxy resin thus obtained. A composition (10% solids) was prepared.

(Examples 2 to 10)
The mass ratio of (a1) and (a2) and the number average molecular weight of (A) were changed as shown in Table 3, respectively, and the preparation of (A) and the preparation of the coating composition were conducted in the same manner as in Example 1. Went.

(Examples 11 to 12)
As shown in Table 4, in Example 1, except that (B) oxazoline-based curing agent 1 was replaced with oxazoline-based curing agents 2, 3, respectively, A coating composition was prepared.

(Examples 13 to 17)
In Example 1, the preparation and coating composition of (A) were performed in the same manner as in Example 1 except that 70 parts by mass of deionized water in Table 2 were replaced with 63 parts by mass of deionized water and 7 parts by mass of benzyl alcohol. Was prepared.

(Comparative Examples 1-8)
As shown in Table 5, in Comparative Examples 1 and 2, the mass ratio between (a1) and (a2) was changed. In Comparative Example 3, (B) was not used. In Comparative Examples 4 and 5, Comparative Resin 1 (acrylic resin) and Comparative Resin 2 (alkyd resin) were used in place of (A), respectively. In Comparative Examples 6 to 8, comparative curing agents 1 to 3 were used in place of (B).

(Spray painting)
The obtained coating composition was applied to an ABS resin plate subjected to chromium (Cr) plating treatment by spray coating so that the film thickness of the cured coating film was 20 μm. Then, it dried by heating at 80 degreeC for 20 minutes, and obtained the coating board which has a coating film.

(Examples 18 to 25: electrodeposition coating)
The ABS resin plates subjected to chromium (Cr) plating treatment were immersed in the coating compositions of Examples 1 to 4, 6, 7, 9, and 10. And the DC voltage of the coating voltage 20V was applied for 3 minutes, and the electrodeposition coating was carried out so that the film thickness of a cured coating film might be set to 15 micrometers. Then, it baked for 30 minutes at 80 degreeC, and obtained the coating board which has a coating film.

(Performance evaluation)
About the coating board which has the coating film obtained by the said Example and comparative example, three types of ethanol resistance and coating-material stability were measured and evaluated as follows. The results are shown in Tables 3-6.

Ethanol resistance (appearance evaluation after immersion test)
A beaker containing ethanol (reagent grade 95% or more) was adjusted to 20 ° C. The prepared coated plate was immersed in it for 1 hour and taken out. Subsequently, after 5 minutes, the coating state of the immersed portion of the coated plate was visually observed and evaluated according to the following criteria. Evaluation 1 is acceptable and evaluations 2 and 3 are unacceptable.
Evaluation 1 (pass): No whitening is observed in the coating film.
Evaluation 2 (failed): Part of the film is whitened.
Evaluation 3 (failed): The entire coating film is whitened and the base of the coated plate is not visible.

Ethanol resistance (adhesion evaluation after immersion test)
As described above, the coated plate was immersed in ethanol for 1 hour, taken out, and allowed to stand for 1 hour. Next, an adhesion (cross-cut method) test was performed based on JIS K 5600-5-6 for the immersed portion of the coated plate. The cut width was 1 mm. The state of the coating film was visually observed and evaluated according to the following criteria. Evaluations 0 to 2 are acceptable and evaluations 3 to 5 are unacceptable.
Evaluation 0 (pass): The edge of the cut is completely smooth, and there is no peeling to the eyes of any lattice.
Evaluation 1 (pass): Small peeling of the coating film at the intersection of cuts. It is clearly not more than 5% that the crosscut is affected.
Evaluation 2 (pass): The coating film is peeled along the edge of the cut and / or at the intersection. The cross-cut part is clearly affected by more than 5% but not more than 15%.
Evaluation 3 (failed): The coating film is partially or completely peeled along the edge of the cut, and / or various parts of the eye are partially or completely peeled off. The cross-cut portion is clearly affected by more than 15% but not more than 35%.
Evaluation 4 (failed): The coating film is partially or completely peeled along the edge of the cut, and / or some eyes are partially or completely peeled off. It is clearly not more than 35% that the cross-cut is affected.
Evaluation 5 (failed): Any of the degree of peeling that cannot be classified even with classification 4.

Ethanol resistance (rubbing test)
A rubbing test is performed by pressing 50 times on a coating film formed with absorbent cotton containing ethanol (reagent grade 95% or more) at a length of 30 mm and a speed of 30 times / minute while applying a load of 1 kgf / cm ^2. went. The state of the coated film after rubbing was visually observed and evaluated according to the following criteria. Evaluations 1 to 3 are acceptable and evaluations 4 to 6 are unacceptable.
Evaluation 1 (pass): There is no scratch.
Evaluation 2 (pass): Scratches are slightly attached.
Evaluation 3 (Pass): There are scratches but no cracks or peeling.
Evaluation 4 (failed): Some cracks and peeling are observed.
Evaluation 5 (failed): The peeling is seen in about half.
Evaluation 6 (failed): Peeling is observed on the entire surface.

The paint-stable paint composition was stored at 40 ° C. for 3 months, and the state of the paint after storage was visually observed and evaluated according to the following criteria. Evaluations 1 to 3 are acceptable and evaluations 4 to 5 are unacceptable.
Evaluation 1 (pass): No settling is observed after storage for 3 months.
Evaluation 2 (pass): No settling is observed after storage for 2 months.
Evaluation 3 (pass): No sedimentation is observed after storage for 1 month.
Evaluation 4 (failed): Sedimentation is observed after storage for 1 month.
Evaluation 5 (failed): Water cannot be dispersed.

  In Comparative Example 1 using a comparative acrylic-modified epoxy resin in which the mass ratio of (a1) and (a2) was out of the predetermined range, an aqueous dispersion could not be obtained in the first place, and ethanol resistance could not be evaluated. Similarly, in Comparative Example 2 using a comparative acrylic-modified epoxy resin in which the mass ratio of (a1) and (a2) is out of the predetermined range, the coating stability was good, but all the ethanol resistance evaluations failed. Met. Even in Comparative Example 3 in which (B) was not used, all the ethanol resistance evaluations failed. (A) In the comparative examples 4 and 5 using an acrylic resin or an alkyd resin instead of the acrylic-modified epoxy resin, all the ethanol resistance evaluations failed. Moreover, it replaced with the (B) oxazoline type hardening | curing agent, also in Comparative Examples 6-8 which used the other hardening | curing agent, all the ethanol-resistant evaluations failed.

  On the other hand, in Example, ethanol resistance was pass in all cases. In particular, when the mass ratio of (a1) and (a2) is 95: 5 to 70:30 (Examples 1 to 3), and when the number average molecular weight of (A) is 8,000 to 28,000 (Examples) 1 to 3, 5 and 8 to 10), all ethanol resistance was particularly excellent in the highest evaluation.

  ADVANTAGE OF THE INVENTION According to this invention, the coating composition which can form the coating film excellent in ethanol resistance under low temperature baking conditions can be provided. Moreover, according to this invention, the articles | goods which have a coating film excellent in ethanol resistance can be provided. Moreover, according to this invention, the formation method of the coating film which can form the coating film excellent in ethanol resistance under low temperature curing conditions can be provided. Moreover, according to this invention, the manufacturing method of the articles | goods which have a coating film excellent in ethanol resistance can be provided.

Claims (7)

(A) an acrylic-modified epoxy resin;
(B) an oxazoline-based curing agent;
Including
(A)
(A1) an epoxy resin;
(A2) a radically polymerizable unsaturated compound including an acidic group-containing radically polymerizable unsaturated compound;
The reaction product of
The mass ratio (a1: a2) between (a1) and (a2) is 95: 5-60: 40,
Paint composition.   The coating composition according to claim 1, wherein the number average molecular weight of (A) is 3,000 to 30,000. (A1) is an aromatic epoxy resin,
The acidic group-containing radical polymerizable unsaturated compound includes a carboxyl group-containing radical polymerizable unsaturated compound,
The coating composition according to claim 1 or 2.   The coating composition according to any one of claims 1 to 3, wherein (a2) does not contain a nitrogen atom.   An article having a coating film formed using the coating composition according to any one of claims 1 to 4. A step of applying a coating composition according to any one of claims 1 to 4 to form a film on an object to be coated;
Drying or heating the coating to form a coating;
A method for forming a coating film, comprising: A step of applying a coating composition according to any one of claims 1 to 4 to form a film on an object to be coated;
Drying or heating the coating to form a coating;
A method for manufacturing an article, comprising: