JP6804008B1 - Paint composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-component coating film composition which has good drying property and can contribute to the formation of a coating film having good adhesion to a base material, particularly a metal base material and weather resistance. A coating composition containing a coating film-forming resin (A), a non-aqueous dispersion acrylic resin (B), and a dryer (C), wherein the coating film-forming resin (A) is an alkyd-modified acrylic resin ( The alkyd-modified acrylic resin (A1) containing A1) has an acrylic resin portion derived from the acrylic resin and an alkyd portion, and is a ratio of the alkyd portion to the alkyd-modified acrylic resin (A1). The modification rate is 5 to 50% by mass, the non-aqueous dispersion type acrylic resin (B) has a core portion and a shell portion, and the glass transition temperature (Tg1) of the core portion is −10 to 40 ° C. The glass transition temperature (Tg2) of the shell portion is in the range of 30 to 100 ° C., and the value of Tg2-Tg1 is 20 to 110 ° C., the coating composition. [Selection diagram] None

Description

The present invention relates to a coating composition.

In a wide range of industrial products such as home appliances, electronic devices, decorations, furniture, and building materials, a paint composition is applied to the surface of the products and parts for the purpose of protection and decoration, and a coating film is formed. Is commonly done.

The coating composition includes a two-component type composed of a main agent and a cross-linking agent, and a one-component type in which the main agent and the cross-linking agent are mixed in advance in a stable state. In the two-component type, it is easy to achieve both the storage stability of the coating composition and the physical properties of the obtained coating film. However, in the two-component type, it is necessary for the user to accurately mix the main agent and the cross-linking agent at a predetermined ratio at the painting site and sufficiently stir, and the usable time is limited. There is a problem in its handling and coating workability, and a one-component coating composition is required.
Further, the coating composition includes a room temperature drying type and a heat drying type depending on the mode of drying and curing thereof. Of these, the room temperature drying type, which does not require a special heating / drying device such as an oven, is generally used.

Examples of the one-component coating composition capable of drying at room temperature include a coating composition containing alkyd resin, which is an oxidation polymerization type resin, as a main component (for example, Patent Document 1), and a non-aqueous dispersion type acrylic resin. (For example, Patent Document 2) includes a coating composition containing the above. Since these are inexpensive and have excellent concealment, workability, and finish, they are widely used mainly for coating metal substrates and wood substrates.

JP-A-2002-30218 Japanese Patent Application Laid-Open No. 2001-64572

In recent years, further improvement in performance has been required, but the above-mentioned coating composition cannot satisfy the required performance.

When the coating composition is applied to an object to be coated, it is generally necessary to recoat the coating composition from the viewpoint of hiding property and uneven gloss. Generally, the second coating is applied after a curing time of 4 hours to 1 day or more after the first coating. In this case, if the second coating is applied while the coating film obtained by the first coating is not sufficiently cured, the first coating film melts, lifts, and the gloss is reduced. May cause malfunctions.
In the case of an oxidative polymerization type coating composition containing an alkyd resin as a main component, generally, it is the second coating after the first coating as compared with a moisture-curable coating composition containing a urethane resin or a siloxane resin as a main component. The interval required for painting is short. However, from the viewpoint of improving the work efficiency of painting, further shortening of the interval is required.

Further, in the case of an oxidative polymerization type coating composition containing an alkyd resin as a main component, the weather resistance is not sufficient for use in outdoor applications such as building exteriors.

As a one-component type coating composition capable of drying at room temperature, which can obtain a coating film having good weather resistance, a coating composition containing a non-aqueous dispersion type acrylic resin as a main component is known.
A coating composition that can be dried at room temperature in a one-component type is generally treated as a so-called topcoat coating composition that is applied to a metal substrate after coating, drying, and curing of the undercoat coating composition. On the other hand, when used for general purposes, the coating composition may be directly coated on the metal substrate.
However, the coating film obtained from the coating composition containing a non-aqueous dispersion type acrylic resin as a main component has a problem that the adhesion to the metal substrate is inferior.

An object of the present invention is to provide a one-component coating film composition having good drying properties and capable of contributing to the formation of a coating film having good adhesion to a base material, particularly a metal base material and weather resistance. And.

The present invention provides the following aspects [1] to [5].
[1]
A coating composition containing a coating film-forming resin (A), a non-aqueous dispersion acrylic resin (B), and a dryer (C).
The coating film-forming resin (A) contains an alkyd-modified acrylic resin (A1).
The alkyd-modified acrylic resin has an acrylic resin portion derived from the acrylic resin and an alkyd portion.
The alkyd modification rate, which is the ratio of the alkyd portion in the alkyd-modified acrylic resin, is 5 to 50% by mass.
The non-aqueous dispersion type acrylic resin (B) has a core portion and a shell portion, and has a core portion and a shell portion.
The glass transition temperature (Tg ₁ ) of the core part is in the range of -10 to 40 ° C.
The glass transition temperature (Tg ₂ ) of the shell portion is in the range of 30 to 100 ° C.
The value of Tg _2- Tg ₁ is 20 to 110 ° C.
Paint composition.
[2]
The coating composition having a mass ratio of the core portion to the shell portion (core portion mass / shell portion mass) in the range of 7/3 to 3/7.
[3]
The mass ratio [(A) / (B)] of the coating film-forming resin (A) to the non-aqueous dispersion acrylic resin (B) is in the range of 1/99 to 50/50. ..
[4]
The coating composition, wherein the dryer (C) contains at least one selected from the group consisting of cobalt, barium, calcium, manganese and zirconium.
[5]
The above-mentioned coating composition for a metal substrate.

According to the present invention, there is provided a one-component coating film composition that has good drying properties and can contribute to the formation of a coating film having good adhesion to a base material, particularly a metal base material and weather resistance. Can be done.

[Paint composition]
The coating composition of the present disclosure will be described.

The coating composition of the present disclosure is
A coating composition containing a coating film-forming resin (A), a non-aqueous dispersion acrylic resin (B), and a dryer (C).
The coating film-forming resin (A) contains an alkyd-modified acrylic resin (A1).
The alkyd-modified acrylic resin (A1) has an acrylic resin portion derived from the acrylic resin and an alkyd portion.
The alkyd modification rate, which is the ratio of the alkyd portion in the alkyd-modified acrylic resin, is 5 to 50% by mass.
The non-aqueous dispersion type acrylic resin (B) has a core portion and a shell portion, and has a core portion and a shell portion.
The glass transition temperature (Tg ₁ ) of the core part is in the range of -10 to 40 ° C.
The glass transition temperature (Tg ₂ ) of the shell portion is in the range of 30 to 100 ° C.
The value of Tg _2- Tg ₁ is 20 ° C to 110 ° C.

<Coating film forming resin (A)>
The coating film forming resin (A) contains an alkyd-modified acrylic resin (A1). The alkyd-modified acrylic resin (A1) may be contained in an amount of 20 to 98 parts by mass or 50 to 95 parts by mass with respect to 100 parts by mass of the coating film-forming resin (A). In one embodiment, the coating film forming resin (A) is an alkyd-modified acrylic resin (A1).

(Alkyd modified acrylic resin (A1))
The alkyd-modified acrylic resin (A1) has at least an acrylic resin portion derived from the acrylic resin and an alkyd portion.
The acrylic resin portion has a structural unit derived from an ethylenically unsaturated monomer (hereinafter, referred to as “component (a-1)”). That is, the acrylic resin portion is a portion obtained by polymerizing the component (a-1).
The alkyd moiety includes a component (a-2) containing a compound having an oxidatively polymerizable functional group, and a structural unit derived from a polybasic acid component (a-3) and / or a polyhydric alcohol component (a-4). Has. The above components may be referred to as "component (a-2)", "component (a-3)", and "component (a-4)", respectively.
The oxidatively polymerizable functional group means a functional group in which oxidative polymerization proceeds by oxygen in the air at room temperature. Examples of the oxidatively polymerizable functional group include carbon-carbon unsaturated bonds (for example, double bonds).
By containing the alkyd-modified acrylic resin (A1) in the coating composition of the present disclosure, the adhesion of the coating film formed from the coating composition to the substrate is improved. This is because, in the coating film formed from the coating composition of the present disclosure, the alkyd portion of the alkyd-modified acrylic resin (A1) forms a three-dimensional network structure, and this structure improves the adhesion of the coating film to the substrate. It is thought that this is because it contributes to. Further, although it should not be construed as being limited to a specific theory, the alkyd portion has better flexibility than the acrylic resin portion, and by having the alkyd portion as described above, the coating film of the present disclosure It is considered that the adhesion of the coating film formed from the composition to the base material (particularly, the metal base material) is improved. Furthermore, the inclusion of the alkyd-modified acrylic resin (A1) improves the weather resistance of the coating film formed from the coating composition of the present disclosure.

In the present disclosure, the "alkyd modification rate" in the alkyd-modified acrylic resin (A1) means the ratio of the alkyd portion in the alkyd-modified acrylic resin (A1). Specifically, the alkyd modification rate is a structural unit derived from the component (a-2), the polybasic acid component (a-3), and the polyhydric alcohol component (a-4) in the alkyd-modified acrylic resin (A1). Shows the ratio based on the mass of.

The alkyd modification rate in the alkyd-modified acrylic resin (A1) is 5 to 50% by mass, preferably 10 to 40% by mass. The alkyd portion has better flexibility than the acrylic resin portion, and by having the alkyd modification rate as described above, the base material (particularly, metal) of the coating film formed from the coating composition of the present disclosure. It is considered that the adhesion to the base material) will be better. Further, having the alkyd modification rate as described above improves the weather resistance of the coating film formed from the coating composition of the present disclosure.

The alkyd moiety contains an oxidatively polymerizable functional group. The iodine value indicating the ratio of the oxidatively polymerizable functional group in the alkyd-modified acrylic resin (A1) is, for example, 2 to 100 and 5 to 50. When the iodine value is in the above range, oxidative polymerization proceeds when the object to be coated (base material) is coated, a three-dimensional network structure can be formed in the coating film, and the adhesion of the coating film to the base material can be formed. Can be better. In the present disclosure, the iodine value indicates the solid content iodine value and is a value measured by the method described in JIS K 0070.

(Component (a-1))
Examples of the component (a-1) include a hydroxyl group-containing ethylenically unsaturated monomer, a carboxyl group-containing ethylenically unsaturated monomer, and other monomers. The hydroxyl value of the alkyd-modified acrylic resin (A1) can be adjusted by the content of the hydroxyl group-containing ethylenically unsaturated monomer.

Examples of the hydroxyl group-containing ethylenically unsaturated monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and these hydroxyl group-containing ethylenically unsaturated monomers. Examples thereof include a reaction product of ε-caprolactone and an esterified product of a polyhydric alcohol such as polyethylene glycol (meth) acrylate and (meth) acrylic acid. Further, a reaction product obtained by ring-opening polymerization of ε-caprolactone on the monoesterified product of the polyhydric alcohol and (meth) acrylic acid can also be used. In addition, in this specification, (meth) acrylic acid means acrylic acid and methacrylic acid. These may be used alone or in combination of two or more.

Examples of the carboxyl group-containing ethylenically unsaturated monomer include carboxylic acid monomers such as (meth) acrylic acid, 2-ethylpropenic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, or dicarboxylic acid monoester monomers thereof. Can be mentioned. As the carboxyl group-containing ethylenically unsaturated monomer, (meth) acrylic acid or the like is preferable. These may be used alone or in combination of two or more.

The other ethylenically unsaturated monomer refers to an ethylenically unsaturated monomer other than the hydroxyl group-containing ethylenically unsaturated monomer and the carboxyl group-containing ethylenically unsaturated monomer.
Examples of other ethylenically unsaturated monomers include the following monomers.
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, -n, i and t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate Etc. (meth) acrylic acid ester monomer;
Alicyclic group-containing monomers such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, adamantyl (meth) acrylate;
Aminoalkyl ester monomers of (meth) acrylate such as aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, butylaminoethyl (meth) acrylate;
(Meta) Acrylic acid aminoalkylamide monomers such as aminoethyl (meth) acrylamide, dimethylaminomethyl (meth) acrylamide, and methylaminopropyl (meth) acrylamide;
Other amide group-containing monomers such as acrylamide, methacrylamide, N-methylolacrylamide, methoxybutylacrylamide, diacetoneacrylamide;
(Meta) Vinyl cyanide-based monomers such as acrylonitrile and α-chloroacrylonitrile;
Epoxy group-containing monomer such as (meth) glycidyl acrylate;
Saturated aliphatic carboxylic acid vinyl ester monomers such as vinyl acetate and vinyl propionate;
Styrene-based monomers such as styrene and α-methylstyrene vinyltoluene; etc.
As the other ethylenically unsaturated monomers, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, styrene and the like are preferably used.
These other monomers may be used alone or in combination of two or more.

(Component (a-2))
The component (a-2) contains a compound having two or more oxidatively polymerizable functional groups in the molecule. By containing such a compound, the component (a-2) contributes to the formation of the alkyd portion, can impart oxidative polymerization property capable of oxidative polymerization to the coating film forming resin, and when coated on the object to be coated. In addition, a three-dimensional network structure can be formed in the coating film by the progress of oxidative polymerization. For example, the adhesion of the formed coating film to the substrate is improved.

The component (a-2) may have, for example, an iodine value of 100 or more, or 130 or more.

Examples of the compound having two or more oxidatively polymerizable functional groups include linoleic acid, linolenic acid, eleostearic acid, ricinolic acid, fish oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, linseed oil fatty acid, and soybean oil fatty acid. , Sesame oil fatty acid, poppy oil fatty acid, eno oil fatty acid, hemp oil fatty acid, grape kernel oil fatty acid, corn oil fatty acid, tall oil fatty acid, sunflower oil fatty acid, cotton seed oil fatty acid, walnut oil fatty acid, rubber seed oil fatty acid, etc. Oil fatty acids, etc .; (semi) dry oils such as flaxseed oil, millet oil, dehydrated castor oil, tall oil, soybean oil, olive oil, saflower oil, rice bran oil, etc .; it can.
The (semi) drying oil fatty acid represents a carboxylic acid having a long-chain hydrocarbon group and having two or more unsaturated groups in it, and the (semi) drying oil is a (semi) drying oil fatty acid. Shows triglyceride. Here, the triglyceride means one glycerin (that is, an alcohol having three OH groups) and three (semi) drying oil fatty acids ester-bonded.

The component (a-2) may further contain the following acid components as long as the physical properties of the component (a-2) are not impaired.
Non-drying oil fatty acids such as coconut oil fatty acids, hydrogenated coconut oil fatty acids, palm oil fatty acids;
Saturated fatty acids such as caproic acid, caproic acid, lauric acid, myristic acid, palmitic acid, stearic acid, etc.;
A monobasic acid such as benzoic acid, crotonic acid, pt-butylbenzoic acid, and versatic acid.
These may be used alone or in combination of two or more.

The alkyd-modified acrylic resin (A1) may further contain components derived from the polybasic acid component (a-3) and / or the polyhydric alcohol component (a-4). The functional groups contained in the polybasic acid component (a-3) and / or the polyhydric alcohol component (a-4) can react with the functional groups contained in the component (a-2), and the coating film has a three-dimensional network structure. It can contribute to the formation of the film.

The polybasic acid component (a-3) is a compound having a plurality of carboxyl groups in its molecular structure. In addition, for example, a compound having a carboxylic acid anhydride formed by performing a dehydration reaction of two carboxyl groups is considered to have two carboxyl groups.

Examples of the polybasic acid component (a-3) include the following compounds.
Aromatic dicarboxylic acids such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, methylterephthalic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride or its anhydrides;
Alicyclic dicarboxylic acids such as tetrahydrophthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, methylhexahydrophthalic acid, methylhexahydrophthalic anhydride, and methylcyclohexene tricarboxylic acid or their anhydrides;
Aliphatic dicarboxylic acids such as succinic acid, succinic anhydride, maleic acid, maleic anhydride, fumaric acid, adipic acid, azelaic acid, and sebacic acid, or their anhydrides.
These may be used alone or in combination of two or more.

The polyhydric alcohol component (a-4) is a compound having at least two hydroxyl groups in its molecular structure.

Examples of the polyhydric alcohol component (a-4) include the following compounds.
Dihydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, and 1,6-hexanediol;
Trihydric or higher polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.
These may be used alone or in combination of two or more.

The alkyd-modified acrylic resin (A1) can be obtained by a known method such as solution polymerization, suspension polymerization, emulsion polymerization, high-temperature pressure continuous polymerization and the like.
In one embodiment, the alkyd-modified acrylic resin (A1) is added to the acrylic resin produced by using the component (a-1), for example, having a carboquil group, a hydroxyl group or an epoxy group, together with the component (a-2). It is a resin formed by reacting the component (a-3) and / or the component (a-4) according to the above.
In one embodiment, the alkyd-modified acrylic resin (A1) is a resin formed by reacting the component (a-2) and, if necessary, the component (a-3) and / or the component (a-4). , A resin formed by graft polymerization of component (a-1). In this case, as the polymerization initiator, for example, a peroxide-based polymerization initiator can be used.

When the alkyd-modified acrylic resin (A1) has a hydroxyl group, the hydroxyl value of the alkyd-modified acrylic resin (A1) is preferably in the range of 5 to 150 mgKOH / g, preferably in the range of 30 to 140 mgKOH / g. More preferred. When the hydroxyl value is within the above range, there is an advantage that a coating film having good adhesion to a base material (particularly a metal base material) and water resistance can be obtained.
In the present disclosure, the hydroxyl value represents the solid content hydroxyl value and is a value measured by the method described in JIS K 0070.

When the alkyd-modified acrylic resin (A1) has an acid group, the acid value of the alkyd-modified acrylic resin (A1) is preferably in the range of 0 to 50 mgKOH / g, and preferably in the range of 0 to 50 mgKOH / g. Is more preferable. When the acid value is within the above range, there is an advantage that a coating film having good adhesion to a metal substrate and water resistance can be obtained.
In the present disclosure, the acid value represents the solid content acid value and is a value measured by the method described in JIS K 0070.

The number average molecular weight of the alkyd-modified acrylic resin (A1) is preferably in the range of 1,000 to 100,000, and more preferably in the range of 2,000 to 50,000. When the number average molecular weight of the acrylic resin is within the above range, the coating workability and curability of the coating composition can be designed within a good range. In the present disclosure, the number average molecular weight can be measured by gel permeation chromatography (GPC) and determined by styrene homopolymer conversion.

The SP value of the alkyd-modified acrylic resin (A1) is preferably in the range of 8.0 to 13.0, and more preferably in the range of 8.5 to 12.0. When the SP value of the alkyd-modified acrylic resin (A1) is within the above range, there is an advantage that a coating composition having excellent storage stability can be obtained.
The SP value is an abbreviation for solubility parameter and is a measure of solubility. The larger the SP value, the higher the polarity, and conversely, the smaller the value, the lower the polarity.
For example, the SP value can be measured by the following method [References: SUH, CLARKE, J. et al. P. S. A-1, 5, 1671 to 1681 (1967)].
As a sample, 0.5 g of an organic solvent is weighed in a 100 ml beaker, 10 ml of acetone is added using a whole pipette, and the mixture is dissolved by a magnetic stirrer. A poor solvent is added dropwise to this sample at a measurement temperature of 20 ° C. using a 50 ml burette, and the point at which turbidity occurs is defined as the amount of the drop. As the poor solvent, ion-exchanged water is used as the high SP poor solvent, and n-hexane is used as the low SP poor solvent, and the dakuten is measured. The SP value δ of the organic solvent is given by the following formula.
δ = (Vml1 / 2δml + Vmh1 / 2δmh) / (Vml1 / 2 + Vmh1 / 2)
Vm = V1V2 / (φ1V2 + φ2V1)
δm = φ1δ1 + φ2δ2
Vi: Molecular volume of solvent (ml / mol)
φi: Body integration rate of each solvent at the turbidity point δi: SP value of solvent ml: Low SP poor solvent mixed system mh: High SP poor solvent mixed system The alkyd-modified acrylic resin (A1) is a plurality of types of alkyd-modified acrylic resins. When, the SP value of the alkyd-modified acrylic resin is calculated by calculating the average value based on the solid content mass ratio in the alkyd-modified acrylic resin (A1) component using the SP value of each alkyd-modified acrylic resin. Can be sought.

The glass transition temperature (Tg) of the acrylic resin portion of the alkyd-modified acrylic resin (A1) is preferably in the range of 0 to 100 ° C, more preferably in the range of 10 to 80 ° C. When the Tg of the acrylic resin portion of the alkyd-modified acrylic resin (A1) is within the above range, the coating film obtained from the coating composition has excellent physical properties and drying properties.

The glass transition temperature (Tg) is the mass fraction of each monomer constituting the acrylic resin portion of the alkyd-modified acrylic resin (A1), and the Tg (K: Kelvin) of the homopolymer derived from each monomer. ) Can be calculated as the inverse of the sum of each quotient obtained by dividing by the value.
More specifically, in the present disclosure, the glass transition temperature (Tg) is calculated by the Fox formula (TG Fox; Bull. Am. Phys. Soc., 1 (3), 123 (1956)). be able to.
For example, when the resin is a polymer of a plurality of monomers, the following general formula:
1 / Tg = wa / Tga + wb / Tgb + ... + wn / Tgn
Let Tg represented by be the Tg of the resin.
here,
Tga: glass transition temperature (K) of homopolymer of monomer A, wa: mass fraction of monomer A,
Tgb: glass transition temperature (K) of homopolymer of monomer B, wb: mass fraction of monomer B,
Tgn: glass transition temperature (K) of homopolymer of monomer N, wn: mass fraction of monomer N,
It means wa + wb + ... + wn = 1.

The coating film-forming resin (A) can include other resins used in the field of coating composition as long as the effects produced by the present disclosure are not impaired. Other resins include epoxy resin and its modified products (acrylic modified epoxy resin, etc.); polyester resin and its modified products (urethane modified polyester resin, epoxy modified polyester resin, silicone modified polyester resin, etc.); acrylic resin and its modified products. (Silicone-modified acrylic resin, etc.); Urethane resin and its modified products (ester-based urethane resin, ether-based urethane resin, carbonate-based urethane resin, epoxy-based urethane resin, etc.); Modified phenol resin, etc.); Phenoxy resin; Epoxy resin and its modified products (urethane-modified epoxy resin, acrylic-modified epoxy resin, etc.); Silicone resin; Resin such as fluororesin. Only one of these resins may be used alone, or two or more of these resins may be used in combination.

<Non-water dispersion type acrylic resin (B)>
The non-aqueous dispersion type acrylic resin (sometimes referred to as "NAD") (B) has a core portion and a shell portion. That is, the non-aqueous dispersion type acrylic resin (B) is an acrylic resin having a two-layer structure of a core portion and a shell portion.
The non-aqueous dispersion type acrylic resin (B) can be dispersed and stabilized using an organic solvent as a medium.

The non-aqueous dispersion type acrylic resin (B) is prepared as resin particles insoluble in this mixed solution by copolymerizing an ethylenically unsaturated monomer in a mixed solution containing a dispersion stable acrylic resin and an organic solvent. Can be done.
The polymerization reaction for obtaining the non-aqueous dispersion type acrylic resin (B) is not particularly limited, but for example, a method obtained by radical polymerization in the presence of a radical polymerization initiator is preferable.
Examples of the radical polymerization initiator include azo initiators such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile); benzoyl peroxide and lauryl peroxide. , T-Butyl Peroctate and the like. The amount of these initiators used is preferably 0.2 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the total ethylenically unsaturated monomers.
The polymerization reaction for obtaining the non-aqueous dispersion type acrylic resin (B) in the organic solvent containing the dispersion-stable acrylic resin can be generally carried out in a temperature range of about 60 to 160 ° C. for about 1 to 15 hours.

The ratio of the dispersion-stable acrylic resin to the ethylenically unsaturated monomer can be arbitrarily selected depending on the intended purpose. For example, the dispersion-stable acrylic resin may be contained in an amount of 3 to 80% by mass, particularly 5 to 60% by mass, based on the total mass of the dispersion-stable acrylic resin and the ethylenically unsaturated monomer. The unsaturated monomer may be contained in an amount of 97 to 20% by mass, and particularly 95 to 40% by mass.
The total ratio of the dispersion-stable acrylic resin and the ethylenically unsaturated monomer in the organic solvent may be 30 to 80% by mass with respect to the total mass of the dispersion-stable acrylic resin and the ethylenically unsaturated monomer, particularly. It may be 40 to 60% by mass.

The dispersion-stable acrylic resin constitutes a shell portion of the non-aqueous dispersion type acrylic resin (B), and a core portion is formed by copolymerizing an ethylenically unsaturated monomer.

(Shell part)
The glass transition temperature Tg ₂ of the shell portion is in the range of 30 to 100 ° C. By having such a structure, the tackiness of the coating composition of the present disclosure is improved. Further, there are advantages that the curability of the coating composition and the appearance of the obtained coating film are improved. The glass transition temperature Tg ₂ of the shell portion is preferably in the range of 40 to 70 ° C., and by having such a range, there is an advantage that the adhesion of the coating composition becomes better. Here, the glass transition temperature Tg ₂ of the shell portion is calculated based on the above-mentioned calculation method of the glass transition temperature (Tg). The "acrylic resin portion of the alkyd-modified acrylic resin (A1)" in the above-mentioned method for calculating the glass transition temperature (Tg) shall be read as "shell portion".

The shell portion is made of a dispersion-stable acrylic resin. The dispersion-stable acrylic resin is not particularly limited as long as it is a resin capable of stably synthesizing the non-aqueous dispersion acrylic resin (B) in an organic solvent.

The shell portion is preferably obtained by polymerizing an ethylenically unsaturated monomer. Examples of the ethylenically unsaturated monomer include the following compounds.
2-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, reactants of these hydroxyl-containing ethylenically unsaturated monomers with ε-caprolactone and (meth) A hydroxyl group-containing ethylenically unsaturated monomer such as an esterified product of a polyhydric alcohol such as polyethylene glycol acrylate and (meth) acrylic acid; (meth) acrylic acid, 2-ethylpropenic acid, crotonic acid, maleic acid, fumaric acid, Carboxylic acid monomers such as itaconic acid or carboxyl group-containing ethylenically unsaturated monomers such as these dicarboxylic acid monoester monomers; styrene monomers such as styrene and α-methylstyrene; methyl (meth) acrylic acid, (meth) acrylic acid (Meta) such as ethyl, propyl (meth) acrylate, -n, i and t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, etc. Acrylic acid esters monomer; amide group-containing monomer such as (meth) acrylamide; glycidyl group-containing ethylenically unsaturated monomer such as (meth) glycidyl acrylate; m-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) An isocyanate group-containing ethylenically unsaturated monomer such as isocyanatoethyl acrylate. These may be used alone or in combination of two or more.

In one embodiment, the shell portion is an acrylic resin obtained by copolymerizing a plurality of types of α-ethylenically unsaturated monomers.

In one embodiment, the shell portion is obtained by polymerizing an ethylenically unsaturated monomer having a functional group. By having such a shell portion, it is possible to form a three-dimensionally crosslinked coating film when used together with a curing agent.

The method for synthesizing the shell portion is not particularly limited, and examples thereof include a method obtained by a radical polymerization reaction in the presence of a radical polymerization initiator, a method obtained by a condensation reaction and an addition reaction, and the like.
Examples of the radical polymerization initiator include azo initiators such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, and lauryl peroxide. , T-Butyl Peroctate and the like. The amount of these initiators used is preferably 0.2 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the total ethylenically unsaturated monomers.
The radical polymerization reaction can generally be carried out in a temperature range of about 60 to 160 ° C. for about 1 to 15 hours.

The hydroxyl value of the shell portion is in the range of 5 to 150 mgKOH / g in one embodiment. Within the above range, there are advantages that the storage stability of the obtained coating composition and the water resistance of the coating film formed from the coating composition are improved.

The acid value of the shell portion is in the range of 0 to 50 mgKOH / g in one embodiment. Within such a range, there are advantages that the curability of the obtained coating composition and the water resistance of the coating film formed from the coating composition are improved.

The SP value of the shell portion is 8.5 to 12.5 in one embodiment, for example, 8.5 to 12.0. Within such a range, there are advantages that the storage stability of the coating composition and the appearance of the coating film formed from the coating composition are improved.

In one embodiment, the number average molecular weight of the shell portion is 1,000 to 100,000 or less, for example, 3,000 to 50,000. Having such a number average molecular weight has an advantage that a coating composition having excellent curability and storage stability can be obtained.

(Core part)
The glass transition temperature Tg ₁ of the core portion is in the range of −10 to 40 ° C. By having such a structure, the adhesion of the coating composition of the present disclosure to the substrate is improved, and the appearance of the coating film is improved. Here, the glass transition temperature Tg ₁ of the core portion is calculated based on the above-mentioned calculation method of the glass transition temperature (Tg). The "acrylic resin portion of the alkyd-modified acrylic resin (A1)" in the above-mentioned method for calculating the glass transition temperature (Tg) shall be read as "core portion".

As described above, the non-aqueous dispersion type acrylic resin (B) can be obtained by polymerizing a radically polymerizable ethylenically unsaturated monomer in the presence of a shell portion (dispersion stable acrylic resin). That is, the core portion is an acrylic resin obtained by copolymerizing an ethylenically unsaturated monomer.

Examples of the ethylenically unsaturated monomer suitable for producing the core portion include the following compounds.
2-Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, reactants of these hydroxyl-containing ethylenically unsaturated monomers with ε-caprolactone and (meth) A hydroxyl group-containing ethylenically unsaturated monomer such as an esterified product of a polyhydric alcohol such as polyethylene glycol acrylate and (meth) acrylic acid; (meth) acrylic acid, 2-ethylpropenic acid, crotonic acid, maleic acid, fumaric acid, Carboxylic acid monomers such as itaconic acid or carboxyl group-containing ethylenically unsaturated monomers such as these dicarboxylic acid monoester monomers; styrenes such as styrene and α-methylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate. , (Meta) propyl acrylate, (meth) acrylate-n, i and t-butyl, (meth) 2-ethylhexyl acrylate, (meth) lauryl acrylate, (meth) acrylic acid such as cyclohexyl (meth) acrylate. Acid esters; Amidos such as (meth) acrylamide; Glycidyl group-containing unsaturated ethylenically unsaturated monomers such as glycidyl (meth) acrylic acid; m-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) acrylic acid An isocyanate group-containing unsaturated ethylenically unsaturated monomer such as isocyanatoethyl.

In one embodiment, the core portion may be formed using a polyfunctional vinyl monomer.
The polyfunctional vinyl monomer is a compound having two or more radically polymerizable ethylenically unsaturated groups in the molecule. Examples of the polyfunctional vinyl monomer include divinylbenzene, ethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, allyl (meth) acrylate, and di (meth). Divinyl compounds such as 1,4-butanediol acrylate, 1,6-hexane di (meth) acrylate, neopentyl glycol di (meth) acrylate, and pentaeristol di (meth) acrylate can be mentioned. Examples thereof include pentaerythritol acrylate, trimethylolpropane tri (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

The hydroxyl value of the core portion is 100 to 450 mgKOH / g in one embodiment. Within the above range, there is an advantage that a coating composition having excellent storage stability can be obtained.

The acid value of the core portion is 0 to 50 mgKOH / g in one embodiment. Within such a range, there is an advantage that a coating composition having excellent curability can be obtained.

In one embodiment, the SP value of the core portion is 11.0 to 15.0, for example, 11.0 to 13.0. Within such a range, there is an advantage that a coating composition having excellent storage stability can be obtained.

In one embodiment, the number average molecular weight of the core portion is 5,000 to 100,000, for example, 8,000 to 50,000. Within such a range, there is an advantage that a coating composition having excellent storage stability can be obtained. The number average molecular weight of the acrylic resin constituting the core portion is obtained by subtracting the molecular weight distribution of the shell portion from the molecular weight distribution of the entire non-aqueous dispersion type acrylic resin (B) to obtain the molecular weight distribution of only the core portion. The value obtained by calculating the number average of.

The glass transition temperature Tg ₁ Metropolitan glass transition temperature Tg ₂ and the core portion of the shell _portion, the value of Tg 2 -Tg ₁ is 20 ° C. to 110 ° C.. The value of Tg _2- Tg ₁ is preferably more than 30 ° C. Due to the above relationship between the glass transition temperature Tg ₁ of the core portion and the glass transition temperature Tg _{2 of the} shell portion, the shell portion becomes harder than the core portion, and the coating film formed from the coating composition of the present disclosure is formed. It is considered that the adhesion of the film to the substrate is improved. In particular, when a metal base material (for example, Fe base material) is used as the base material, the coating film formed from the coating composition of the present disclosure is more difficult to peel off from the base material. Further, having the glass transition temperature as described above can contribute to shortening the drying time of the coating composition.

The mass ratio of the core portion to the shell portion (core portion mass / shell portion mass) is preferably in the range of 7/3 to 3/4, and preferably in the range of 6/4 to 4/6. More preferred. Within the above range, there is an advantage that the non-aqueous dispersion type acrylic resin (B) can maintain a stable dispersed state in the coating composition. The mass ratio can be obtained from the ratio of the blending amount of the core portion and the shell portion.
In the present disclosure, the mass ratio means the solid content mass ratio.

The core portion and the shell portion may be crosslinked, or may be crosslinked at the core portion. Acrylic group or methacrylic group contained in the shell part or the core part, and vinyl group, isocyanate group, allyl group, epoxy group or acid anhydride group contained in the monomer contained in the shell part or the core part as needed. A graft structure or a crosslinked structure may be formed between them. By adjusting the amount of these functional groups, the degree of cross-linking can be adjusted.

In one embodiment, an ethylenically unsaturated monomer having a functional group may be used in the synthesis of the non-aqueous dispersion type acrylic resin (B). The non-aqueous dispersion type acrylic resin (B) having a functional group can form a three-dimensionally crosslinked coating film when used together with a curing agent.

The average particle size of the non-aqueous dispersion type acrylic resin (B) is preferably in the range of 100 to 1,000 nm, and may be in the range of, for example, 100 to 500 nm.
In the present disclosure, the average particle size is the volume average particle size (D50), and can be measured using a particle size measuring device such as a laser diffraction / scattering type particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Microtrac). it can.

In one embodiment, the number average molecular weight of the non-aqueous dispersion acrylic resin (B) is in the range of 1,000 to 100,000, and may be in the range of, for example, 5,000 to 50,000.

The non-aqueous dispersion type acrylic resin (B) has a hydroxyl value of 50 to 350 mgKOH / g, preferably 100 to 300 mgKOH / g, and an acid value of 0 to 70 mgKOH / g, preferably 0 to 50 mgKOH / g. Is preferable.

In one embodiment, the mass ratio [(A) / (B)] of the coating film-forming resin (A) to the non-aqueous dispersion type acrylic resin (B) is 1/99 to 50/50, preferably 1/99 to 50/50. It is 5/95 to 40/60, for example, 10/85 to 35/65. Within the above range, the coating composition of the present disclosure has an advantage of being excellent in drying property, and the coating film obtained from the coating composition has an advantage of being excellent in appearance and tack property.
In the present disclosure, when two or more kinds of the coating film forming resin (A) and / or the non-aqueous dispersion type acrylic resin (B) are used in combination, it means the total mass of each solid content.

In one embodiment, the mass ratio [(A1) / (B)] of the alkyd-modified acrylic resin (A1) to the non-aqueous dispersion acrylic resin (B) is 1/99 to 50/50, preferably 1/99 to 50/50. It is 5/95 to 40/60, for example, 10/85 to 35/65. Within the above range, the coating composition of the present disclosure has an advantage that it is more excellent in drying property, and the coating film obtained from the coating composition is excellent in appearance and tackiness.

<Dryer (C)>
The coating composition of the present disclosure includes a dryer (C), specifically a metal dryer. This metal dryer serves to crosslink unsaturated bonds.
The metal dryer is not particularly limited, and a metal dryer commonly used for paints can be used. Examples of the metal dryer include cobalt, barium, vanadium, manganese, cerium, lead, iron, calcium, zinc, zirconium, cerium, nickel and tin. In one embodiment, the metal dryer comprises at least one selected from the group consisting of cobalt, barium, vanadium, calcium, manganese and zirconium.

As the metal dryer, the above-mentioned metal naphthenate, octylate and the like can be used.

The amount of the metal dryer added is, for example, 0.01 to 2.5 with respect to 100 parts by mass of the total resin solid content of the alkyd-modified acrylic resin (A1) and the non-aqueous dispersion type acrylic resin (B). It can be in the range of parts by mass. Within the above range, there is an advantage that a coating film having excellent adhesion to a base material and weather resistance can be obtained.

(Other resins)
In the coating composition of the present disclosure, in addition to the coating film forming resin (A) and the non-aqueous dispersion type acrylic resin (B), other coating films are used as long as they do not affect the performance of the coating film composition and the obtained coating film. A resin may be used in combination.
Examples of the other resins include epoxy resin and its modified product (acrylic modified epoxy resin, etc.); polyester resin and its modified product (urethane modified polyester resin, epoxy modified polyester resin, silicone modified polyester resin, etc.); acrylic resin and its modified product. (Silicone-modified acrylic resin, etc.); Urethane resin and its modified products (ester-based urethane resin, ether-based urethane resin, carbonate-based urethane resin, epoxy-based urethane resin, etc.); Phenolic resin and its modified products (acrylic-modified phenol resin, etc.) Epoxy-modified phenolic resin, etc.); Phenoxy resin; alkyd resin and its modified products (urethane-modified alkyd resin, acrylic-modified alkyd resin, etc.); Silicone resin; resin such as fluororesin. These resins may be used alone or in combination of two or more.

(Hardener)
The coating composition of the present disclosure may contain a curing agent, if necessary.
The curing agent can include a known curing agent, and may include, for example, a polyisocyanate, a blocked polyisocyanate compound, and the like.
Examples of the polyisocyanate compound include 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), and a mixture thereof (TDI), diphenylmethane-4,4'-. Diisocyanate (4,4'-MDI), diphenylmethane-2,4'-diisocyanate (2,4'-MDI), and mixtures thereof (MDI), naphthalene-1,5-diisocyanate (NDI), 3,3'- Dimethyl-4,4'-biphenylenediocyanate (TODI), xylylene diisocyanate (XDI), dicyclohexylmethane diisocyanate (hydrogenated HDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), hydride xylylene diisocyanate (HXDI) and the like.
These may be used alone or in combination of two or more.

(Other additives)
The coating composition of the present disclosure may contain other additives other than the above, if necessary.
Other additives include, for example, extender pigments; colorants such as color pigments and dyes; bright pigments; heat shield pigments; waxes; solvents; UV absorbers (UVA, benzophenon-based UV absorbers, etc.); light stabilizers. (HALS); Antioxidants (phenolic, sulfoid, hindered amine antioxidants, etc.); Plastics; Coupling agents (silane, titanium, zirconium couplings, etc.); Anti-sagging agents; Thickeners Pigment dispersant; Pigment wetting agent; Surface conditioner; Leveling agent; Color-coding inhibitor; Precipitation inhibitor; Antifoaming agent; Skin burr inhibitor; Antifreeze agent; Emulsifier; Preservative; Antifungal agent; Antibacterial agent; Stabilizers: Adhesion imparting agents and the like. These additives may be used alone or in combination of two or more.

Examples of the extender pigment include calcium carbonate, barium sulfate, clay, talc, mica, silica and the like. Only one of these may be used alone, or two or more thereof may be used in combination.
In one embodiment, the amount of the extender pigment is 1 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the total solid content of the alkyd-modified acrylic resin (A1) and the non-aqueous dispersion type acrylic resin (B). For example, it is 10 parts by mass or more and 30 parts by mass or less. When the content of the extender pigment is within such a range, there is an advantageous effect that the drying property of the coating composition and the appearance of the obtained coating film are improved.

Colored pigments include, for example, colored inorganic pigments such as titanium dioxide, carbon black, graphite, iron oxide, and cole dust; phthalocyanine blue, phthalocyanine green, quinacridone, perylene, anthrapymidin, carbazole violet, anthrapyridine, azoorange, and flavanthrone. Colored organic pigments such as yellow, isoindoline yellow, azo yellow, induslon blue, dibrom anzaslon red, perylene red, azo red, anthraquinone red; aluminum powder, alumina powder, bronze powder, copper powder, tin powder, zinc powder, Examples thereof include iron phosphate and atomized titanium. These may be used alone or in combination of two or more.
In one embodiment, the amount of the coloring pigment may include 1 part by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the total solid content of the alkyd-modified acrylic resin (A1) and the non-aqueous dispersion type acrylic resin (B). , This allows the desired hue to be prepared.

Examples of the glitter pigment include aluminum foil, bronze foil, tin foil, gold leaf, silver foil, titanium metal foil, stainless steel foil, alloy foil such as nickel and copper, and foil pigment such as foil-like phthalocyanine blue. .. These may be used alone or in combination of two or more.

Examples of the heat shield pigment include a white heat shield pigment, a red heat shield pigment, a blue heat shield pigment, a yellow heat shield pigment, and a black heat shield pigment. The heat-shielding pigment does not absorb light in the near-infrared wavelength region (wavelength: 780 nm to 2,500 nm), or has a small light absorption rate in the near-infrared wavelength region (wavelength: 780 nm to 2,500 nm). Refers to a pigment.
The heat-shielding pigment used is not particularly limited, and examples thereof include the following heat-shielding pigments.
Examples of the white heat-shielding pigment include Titanium Oxide, Typaque CR-97 (manufactured by Ishihara Sangyo Co., Ltd.) and the like.
Examples of the red heat-shielding pigment include Fastogen Super Magenta RH (manufactured by DIC), Fastogen Super Red 7100Y (manufactured by DIC), Rubycron Red 400RG (manufactured by Tosoh), Pacific Red 2020 (manufactured by BASF), and the like. it can. Further, two or more of these red primary color pigments may be used in combination.
As blue heat-shielding pigments, Dipiroxide Blue # 9453 (manufactured by Dainichiseika Kogyo), Fastogen Blue 5485K (manufactured by DIC), Fastogen Blue RSKE (manufactured by DIC), Cyanin Blue 5240KB (manufactured by Dainichiseika Kogyo) ), Lionol Blue SPG-8 (manufactured by Toyo Color Co., Ltd.) and the like. Two or more of these blue primary color pigments may be used in combination.
Examples of the yellow heat-shielding pigment include Symuler Fast Yellow 4192 (manufactured by DIC), Sicopearl Yellow L-1110 (manufactured by BASF), Irga Color Yellow 2GLMA (manufactured by BASF) and the like. Two or more of these yellow primary color pigments may be used in combination.
Examples of the black heat-shielding pigment include azomethiazo pigments, perylene pigments, aniline pigments, and composite oxide fired pigments. Two or more of these black primary color pigments may be used in combination.
Moreover, the primary color pigment described here is an example, and the “pigment” disclosed in the present disclosure may be selected and used. For example, in the present disclosure, various components described as the above pigments may have a function as a heat-shielding pigment.

As the wax, a wax known to those skilled in the art for paints can be used. Examples of the wax include microcrystallin, polyethylene, polypropylene, paraffin, carnauba and modified products thereof.

Examples of the solvent (organic solvent) include ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and dipropylene glycol monomethyl. Glycol-based organic solvents such as ether, dipropylene glycol monoethyl ether and propylene glycol monomethyl ether acetate; alcohol-based organic solvents such as methanol, ethanol and isopropyl alcohol; ether-based organic solvents such as dioxane and tetrahydrofuran; 3-methoxybutyl acetate, Ester-based organic solvents such as ethyl acetate, isopropyl acetate, butyl acetate; ketone-based organic solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, isophorone; and N-methyl-2-pyrrolidone, toluene, pentane, iso-pentane. , Hexine, iso-hexane, cyclohexane, solvent naphtha, mineral spirit, Solbesso 100, Solbesso 150 (all are aromatic hydrocarbon solvents, manufactured by Shell Chemical Co., Ltd.) and the like. These may be used alone or in combination of two or more.
In one embodiment, the amount of the solvent may be 1 part by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the total solid content of the alkyd-modified acrylic resin (A1) and the non-aqueous dispersion type acrylic resin (B). .. When the solvent content is within such a range, the viscosity of the coating composition can be appropriately adjusted, and can be appropriately adjusted according to the coating method described later, the shape of the object to be coated, and the like.

[Preparation method of paint composition]
The method for preparing the coating composition of the present disclosure is not particularly limited. For example, it can be prepared by selecting and using a mixer such as a sand grind mill, a ball mill, a blender, a paint shaker or a disper, a disperser, a kneader, etc., and mixing each component.

[Object to be coated]
Examples of the object to be coated with the coating composition of the present disclosure include metal substrates such as iron, zinc, tin, copper, titanium, tinplate, and galvanized iron. By coating the coating composition of the present disclosure, the adhesion of the coating film formed from the coating composition to the metal substrate is improved.

These metal substrates may be plated with zinc, copper, chromium, etc., or may be subjected to chemical conversion treatment with a surface treatment agent such as chromic acid, zinc phosphate, or zirconium salt. Good. By coating the coating composition of the present disclosure on the metal substrate subjected to the chemical conversion treatment in this way, the adhesion of the coating film to the metal substrate is further improved.

The coating film formed from the coating film composition of the present disclosure has a good protective function and a decorative function even if it is one layer, but the coating film composition of the present disclosure is applied as a topcoat coating film on the undercoat coating film. You may. In this case, as the undercoat paint for forming the undercoat coating film, known ones such as electrodeposition paints and primers can be used.

The coating composition of the present disclosure may be directly applied to an object to be coated, and for example, the coating composition of the present disclosure may be applied as a top coating on an undercoat coating film.

[Coating film forming method]
The method for applying the coating composition of the present disclosure is not particularly limited, and for example, immersion, brush, roller, roll coater, air spray, airless spray, curtain flow coater, roller curtain coater, die coater, electrostatic coating and the like are generally used. Examples include the coating method used. Among these, it is preferable to use a brush, a roller, an air spray, and an airless spray. These can be appropriately selected according to the use and shape of the object to be coated.

The coating composition is preferably coated in an amount having a dry film thickness in the range of 10 to 300 μm, and more preferably in an amount in the range of 20 to 200 μm.

Curing of the coating composition can be carried out at a temperature of 20 ° C. to 150 ° C., preferably 20 ° C. to 100 ° C., for example, over 10 minutes to 7 days.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the examples, "parts" and "%" are based on mass unless otherwise specified.

[Manufacturing method of alkyd-modified acrylic resin (A1-1)]
400 parts by mass of butyl acetate was placed in a reaction vessel equipped with a stirrer, a temperature controller, a cooling tube, a nitrogen introduction tube and a dropping funnel, and the temperature was raised to 110 ° C. while stirring in a nitrogen atmosphere to maintain the above temperature. .. To this, a monomer solution consisting of 164 parts by mass of styrene, 50 parts by mass of 2-hydroxyethyl acrylate, 52 parts by mass of n-butyl acrylate, 434 parts by mass of t-butyl methacrylate and 100 parts by mass of glycidyl methacrylate, and butyl acetate. A solution of an initiator consisting of 147 parts by mass and 15 parts by mass of t-butylperoxy-2-ethylhexanoate (manufactured by Acrylic Acid Chemicals Co., Ltd.) as an initiator is simultaneously added dropwise at a constant velocity for 3 hours through separate addition funnels. did.
After the completion of the dropping, stirring was continued for another 1 hour.

Then, an initiator solution consisting of 80 parts by mass of butyl acetate and 10 parts by mass of t-butylperoxy-2-ethylhexanoate was added dropwise over 30 minutes at a constant velocity.
After completion of the dropping, stirring was continued for another 1 hour to obtain 1,452 parts by mass of acrylic resin (solid content concentration: 55% by mass). The various special values of acrylic resin 1 were number average molecular weight: 8,400, acid value: 0 mgKOH / g, hydroxyl value: 30 mgKOH / g, and Tg: 80 ° C.

Next, the nitrogen inlet of the reaction vessel was removed, and 0.2 parts by mass of hydroquinone monomethyl ether (manufactured by Showa Kagaku Co., Ltd.) as a polymerization inhibitor and tetrabutylammonium bromide (Koei) as a catalyst were placed in the reaction vessel kept at 110 ° C. (Manufactured by Chemical Industry Co., Ltd.) 2 parts by mass was added, and the mixture was stirred in an air atmosphere for 10 minutes.
Then, 200 parts by mass of linoleic acid (iodine value: 181) was added dropwise over 30 minutes at a constant velocity as an acid component, and stirring was continued until no decrease in the acid value of the reaction product was observed (that is, until the acid value became 0). Then, an alkyd-modified acrylic resin (A1-1) (solid content concentration: 60% by mass) was obtained. The special values of the alkyd-modified acrylic resin (A1-1) were iodine value: 36, number average molecular weight: 9,000, solid acid value: 0 mgKOH / g, and SP value: 9.9.

Coating film-forming resins (A1-2) to (A1-8) and (A2-1) were prepared in the same manner as above, except that the monomer type and amount were changed as shown in Table 1A or 1B. The monomer composition and various characteristic values of each resin are shown in Tables 1A and 1B.

The components other than linoleic acid used as the component (a-2) are as follows.
-Linolenic acid (iodine value: 274)

[Manufacturing method of non-aqueous dispersion type acrylic resin (B-1)]
(Manufacturing of shell part)
750 parts by mass of butyl acetate was placed in a reaction vessel equipped with a stirrer, a temperature controller, a cooling tube, a nitrogen introduction tube and a dropping funnel, and the temperature was raised to 110 ° C. while stirring in a nitrogen atmosphere to maintain the above temperature. .. To this, 400 parts by mass of styrene, 139 parts by mass of 2-hydroxyethyl methacrylate, 15 parts by mass of methacrylic acid, 25 parts by mass of i-butyl methacrylate, 400 parts by mass of t-butyl methacrylate and 21 parts by mass of n-butyl acrylate. A monomer solution consisting of 200 parts by mass of butyl acetate and an initiator solution consisting of 30 parts by mass of t-butylperoxy-2-ethylhexanoate as an initiator are simultaneously passed through separate dropping funnels at a constant velocity for 3 hours. Dropped. After the completion of the dropping, stirring was continued for another 1 hour. Then, an initiator solution consisting of 50 parts by mass of butyl acetate and 3 parts by mass of t-butylperoxy-2-ethylhexanoate was added dropwise over 30 minutes at a constant velocity. After completion of the dropping, stirring was continued for another 1 hour to obtain a shell portion (resin solid content concentration: 50% by mass) of the non-aqueous dispersion acrylic resin. The various special values of the shell portion are number average molecular weight: 5,000, solid content acid value: 10 mgKOH / g, solid content hydroxyl value: 60 mgKOH / g, Tg ₂ : 100 ° C., SP value: 9.9. It was.

(Manufacturing of non-aqueous dispersion type acrylic resin (B-1))
In a reaction vessel equipped with a stirrer, a temperature controller, a cooling pipe, a nitrogen introduction pipe and a dropping funnel, 2,000 parts by mass of the shell portion and 400 parts by mass of butyl acetate obtained above were charged and stirred in a nitrogen atmosphere. While raising the temperature to 110 ° C., the above temperature was maintained. To this, a monomer solution consisting of 50 parts by mass of styrene, 514 parts by mass of methyl methacrylate, 53 parts by mass of n-butyl acrylate, 368 parts by mass of 2-hydroxyethyl acrylate and 15 parts by mass of methacrylic acid, and 500 parts by mass of butyl acetate. An initiator solution consisting of 5 parts by mass of t-butylperoxy-2-ethylhexanoate as an initiator was simultaneously added dropwise at a constant velocity for 3 hours through separate dropping funnels. After the completion of the dropping, stirring was continued for another 1 hour.
Then, an initiator solution consisting of 60 parts by mass of butyl acetate and 4 parts by mass of t-butylperoxy-2-ethylhexanoate was added dropwise over 30 minutes at a constant velocity. After completion of the dropping, stirring was continued for another 1 hour to obtain a non-aqueous dispersion type acrylic resin (B-1) (resin solid content concentration: 50% by mass). The special values of the non-aqueous dispersion type acrylic resin (B-1) are number average molecular weight: 8,000, solid content acid value: 10 mgKOH / g, solid content hydroxyl value: 120 mgKOH / g, Tg: 70 ° C., SP was 11.0. Among the non-aqueous dispersion type acrylic resin (B-1), various special values of the core portion are number average molecular weight: 11,000, solid content acid value: 10 mgKOH / g, solid content hydroxyl value: 180 mgKOH / g. , Tg ₁ : 40 ° C., SP: 12.0.

Non-aqueous dispersion type acrylic resins (B-2) to (B-17) were prepared in the same manner as above except that the monomer species and amounts were changed as shown in Tables 2A to 2D. The monomer composition and various characteristic values of each resin are shown in Tables 2A to 2D.

(Example 1)
<Manufacturing of paint composition 1>
Stir 15 parts by mass of the alkyd-modified acrylic resin (A1-1) obtained above, 15 parts by mass of butyl acetate as a solvent, and 20 parts by mass of TIPAQUE CR-95 (titanium oxide, manufactured by Ishihara Sangyo Co., Ltd.) as a pigment with a disper. Mixing gave a mixture.
Next, the entire amount of the obtained mixture and 60 parts by mass of glass beads were placed in a tabletop SG mill 1500W type disperser (manufactured by Ohira System Co., Ltd.), and pigment dispersion was carried out until the particle size of the pigment elementary particles became 15 μm or less. , Pigment dispersion solution was prepared.
Further, 50 parts by mass of the non-aqueous dispersion acrylic resin (B-1) obtained above and 6% 0.1 part by mass of cobalt octylate as a dryer (C1) are mixed with this pigment dispersion solution by stirring with a disper. Then, the coating composition 1 was obtained.

(Examples 2-27, Comparative Examples 1-9)
As shown in Tables 3A to 3F, a coating composition was prepared in the same manner as in Example 1 except that the types and contents of the coating film forming resin, the non-aqueous dispersion type acrylic resin and the dryer were changed.

The details of the component (C) used in Examples and Comparative Examples are as follows.
Dryer (C):
(C1) Cobalt octylate 6% (manufactured by DIC; active ingredient concentration: 6% by mass)
(C2) Manganese octylate 8% (manufactured by DIC; active ingredient concentration: 8% by mass)

The following evaluations were carried out using the coating compositions obtained in Examples and Comparative Examples. The evaluation results are shown in Tables 3A to 3F.

[Evaluation item]
1) Dryness (touch time, curing time)
After solvent degreasing of a JIS G 3141 (SPCC to SD) cold-rolled steel sheet having a thickness of 0.8 mm and a size of 70 x 150 mm, the coating composition obtained in Example or Comparative Example was used in NK2 cup Anest Iwata for 15 seconds. After diluting with butyl acetate so as to be (25 ° C.), it was painted with a spray so as to have a dry film thickness of 30 μm.
The time required for the film obtained by coating to reach a "dry to the touch" state based on the provisions of JIS K 5600-1-1 under the conditions of a temperature of 23 ° C. and a humidity of 50% was measured.
⊚: Drying to the touch is within 5 minutes.
〇: Dryness to the touch exceeds 5 minutes and less than 15 minutes.
X: Drying to the touch is 15 minutes or more.

2) Tackability After solvent degreasing of a JIS G 3141 (SPCC-SD) cold-rolled steel sheet having a thickness of 0.8 mm and a size of 70 × 150 mm, the coating composition obtained in Example or Comparative Example was subjected to a dry film thickness of 30 μm. It was painted with a spray and dried under the conditions of a temperature of 23 degrees and a humidity of 50% for 24 hours.
The state when the finger was pressed against the coating film after drying for 10 seconds was evaluated according to the following criteria.
◯: There is no stickiness of the coating film.
X: The stickiness of the coating film remains.

<Manufacturing example of test plate>
After solvent degreasing of a JIS G 3141 (SPCC to SD) cold-rolled steel sheet having a thickness of 0.8 mm and a size of 70 × 150 mm, the coating composition obtained in Example or Comparative Example was adjusted to have a dry film thickness of 30 μm. , Painted with a spray and dried at room temperature for 7 days to obtain a test plate having a dry coating.

3) Appearance of coating film (gloss)
The 60 ° glossiness of the coating film formed on the test plate is based on JIS K 5600-4-7 (mirror surface glossiness) using a mirror surface gloss meter (gloss meter VG 7000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.)). Was measured.
〇: Gloss value is 90 or more ×: Gloss value is less than 90

4-1) Adhesiveness (adhesion to substrate) (adhesiveness before water resistance test)
The coating film formed on the test plate was tested as follows in accordance with JIS K 5600-5-6 (cross-cut method).
The coating layer on the surface of the coated plate was cut with a cutter knife in 6 vertical and horizontal cuts at intervals of 2 mm so as to be orthogonal to each other, and 25 square cuts were made in a right-angled grid pattern. .. Next, a cellophane tape (registered trademark) (manufactured by Nichiban Co., Ltd.) was attached onto the tape, which was then peeled off and evaluated according to the provisions of JIS K 5600-5-6 8.3. The evaluation criteria are as follows.
⊚: Classification 0, Classification 1
◯: Classification 2
×: Classification 3, Classification 4, Classification 5

4-2) Adhesiveness (adhesiveness after water resistance test)
After immersing the test plate in water at 20 ° C. for 120 hours (5 days), the test plate was taken out of the water, and after 5 days had passed at room temperature (immediately after taking out), a grid test was carried out in the same manner as described above.

5) Accelerated weather resistance test plate is accelerated weather resistance for 1,500 hours using Sunshine Weather Meter S80 (manufactured by Suga Test Instruments Co., Ltd.), which is a sunshine carbon arc lamp type accelerated weather resistance tester specified in JIS B 7753. The test was conducted. The operating conditions are as follows: Irradiance: 255 W / m ²
Black panel temperature: 63 ° C
Water injection time: 18 minutes out of 120 minutes The 60 ° gloss value of the coating film before the accelerated weather resistance test and the 60 ° gloss value of the coating film after the accelerated weather resistance test are measured by the gloss meter GN-268Plus (Konica Minolta). The rate of change (gloss retention rate) with respect to the 60 ° gloss value before the test was calculated. The evaluation criteria are as follows.
⊚: The gloss retention rate was 90% or more. ◯: The gloss retention rate was 75% or more and less than 90%.
X: The gloss retention rate was less than 75%.

As shown in the above table, all the coating films formed by using the coating compositions of Examples had good drying properties, and had good adhesion to the substrate and weather resistance. In Examples 17 to 19, non-aqueous dispersion type acrylic resins having different core mass / shell mass were used. In the coating composition of Example 17, a non-aqueous dispersion type acrylic resin was particularly stably present, and aggregation and sedimentation did not occur.
The coating compositions of Comparative Examples 1 to 3 and 7, in a non-aqueous dispersion type glass transition shell portion of the acrylic resin temperature Tg ₂ and the core portion glass transition temperature Tg _{1 Tokyo,} the value of Tg 2 -Tg ₁ is 20 ° C. It is outside the range of ~ 110 ° C. It was confirmed that the coating films obtained in these comparative examples were inferior in adhesion to the coated plate (base material).
Further, in the non-aqueous dispersion type acrylic resins of Comparative Examples 2 and 7, the glass transition temperature Tg ₂ of the shell portion is low and the glass transition temperature Tg ₁ of the core portion is high. It was confirmed that the coating films obtained in these comparative examples were inferior in dryness as well as adhesiveness.
The coating compositions of Comparative Examples 4 and 5 do not contain an alkyd-modified acrylic resin. It was confirmed that the coating films obtained in these comparative examples were inferior in adhesion to the coated plate (base material).
In the coating composition of Comparative Example 6, the alkyd modification rate of the alkyd-modified acrylic resin is high. It was confirmed that the coating film obtained in Comparative Example 6 was inferior in accelerated weather resistance.
The coating composition of Comparative Example 8 does not include a dryer. It was confirmed that the coating film obtained in Comparative Example 8 was inferior in adhesion to the coated plate (base material).
The coating composition of Comparative Example 9 does not contain the alkyd-modified acrylic resin (A1). It was confirmed that the coating film obtained in Comparative Example 9 had inferior substrate adhesion.

The coating composition of the present disclosure can contribute to the formation of a coating film having good adhesion to a substrate and weather resistance. Further, since the coating composition of the present disclosure has good drying properties, it can also contribute to improvement of work efficiency.

Claims (5)

A coating composition containing a coating film-forming resin (A), a non-aqueous dispersion acrylic resin (B), and a dryer (C).
The coating film-forming resin (A) contains an alkyd-modified acrylic resin (A1).
The alkyd-modified acrylic resin (A1) has an acrylic resin portion derived from the acrylic resin and an alkyd portion.
The alkyd modification rate, which is the ratio of the alkyd portion, in the alkyd-modified acrylic resin (A1) is 5 to 50% by mass.
The non-aqueous dispersion type acrylic resin (B) has a core portion and a shell portion, and has a core portion and a shell portion.
The glass transition temperature (Tg ₁ ) of the core part is in the range of -10 to 40 ° C.
The glass transition temperature (Tg ₂ ) of the shell portion is in the range of 30 to 100 ° C.
The value of Tg _2- Tg ₁ is 20 to 110 ° C.
Paint composition. The coating composition according to claim 1, wherein the mass ratio of the core portion to the shell portion (core portion mass / shell portion mass) is in the range of 7/3 to 3/7. The mass ratio [(A) / (B)] of the coating film-forming resin (A) to the non-aqueous dispersion acrylic resin (B) is in the range of 1/99 to 50/50, claim 1 or 2. The coating composition according to 2. The coating composition according to any one of claims 1 to 3, wherein the dryer (C) contains at least one selected from the group consisting of cobalt, barium, calcium, manganese and zirconium. The coating composition according to any one of claims 1 to 4, which is used for a metal substrate.