JP2002241702A - Composition for outdoor coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which is a one-part type colored outdoor coating composition comprising a pigment, having excellent curability at normal temperature and providing a film having film properties of excellent weather resistance, or the like. SOLUTION: This outdoor coating composition comprises (A) a polymer having maleimide groups, (B) a pigment and (C) a photosensitizer or/and a photopolymerization initiator as essential components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outdoor paint composition, which can be easily applied with a one-pack type paint, and the resulting coating film has excellent properties such as weather resistance and solvent resistance. , Paints, construction and civil engineering.

[0002]

2. Description of the Related Art The present inventors have found a coating composition containing a polymer having a maleimide group as a coating for providing a coating film having excellent weather resistance (Japanese Patent Application No. 2000-27076).
6, Japanese Patent Application No. 2000-270767). When a coating film formed from the composition is dried outdoors, the maleimide group undergoes a crosslinking reaction by a photodimerization reaction with sunlight even at room temperature to form a coating film having excellent weather resistance.

[0003]

However, if the above composition is a clear coating composition containing no pigment, the curing reaction proceeds in a short time, but in the case of a colored coating composition containing a pigment, In some cases, the curing reaction was extremely slow.

[0004] As a method for solving the above problem, the present inventors have used a composition in which a copolymer having a maleimide group and a hydroxyl group and a polyisocyanate are used in combination, and utilize the urethanization reaction between the polyisocyanate and the hydroxyl group. And a composition having an increased initial curing rate (Japanese Patent Application No. 11-344275).
No. 11) and a composition using crosslinking by condensation of an alkoxysilyl group using a copolymer having a maleimide group and a hydrolyzable silyl group (Japanese Patent Application No. 11-362080).
Has also proposed. However, each of these compositions is a two-pack type composition in which a main agent and a curing agent are mixed at the time of coating, and the coating process is complicated, so that a one-pack type coating material having a sufficient curing speed is desired. Was.

The present inventors have proposed a one-pack type colored outdoor coating composition containing a pigment, which has excellent curability at room temperature and has a coating film having excellent coating properties such as weather resistance. We did diligent examination to find out.

[0006]

Means for Solving the Problems The inventors of the present invention provide a coating composition containing a maleimide group-containing copolymer,
If the sensitivity of the maleimide group in the copolymer to sunlight is increased, a sufficient curing speed cannot be obtained without deteriorating the coating properties such as weather resistance even in a composition containing a pigment. As a result of various studies based on the idea of the fact, the present invention has been completed. Hereinafter, the present invention will be described in detail. In this specification, acrylate or methacrylate is represented as (meth) acrylate, and acrylic acid or methacrylic acid is represented as (meth) acrylic acid.

1. (A) Polymer Having Maleimide Group As the component (A) of the present invention, those produced by various methods can be used. As the component (A), in terms of easy production,
A homopolymer of an ethylenically unsaturated monomer having a maleimide group (hereinafter referred to as maleimide monomer), or a maleimide monomer and an ethylenically unsaturated monomer copolymerizable therewith (hereinafter simply referred to as unsaturated monomer) Is preferred.) Hereinafter, the maleimide monomer will be described.

1-1. Maleimide monomer As the maleimide monomer, a compound having an ethylenically unsaturated group and a cyclic imide group represented by the following formula (1) is preferable.

[0009]

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(However, in the formula (1), R ¹ and R ² are each independently a hydrogen atom or an alkyl group, one of them is a hydrogen atom and the other is an alkyl group, or each is bonded to form a carbon ring. It is a group to do.)

In the maleimide monomer, examples of the ethylenically unsaturated group include a vinyl group and a (meth) acryloyl group, and a (meth) acryloyl group is preferable.

R ¹ and R ² are each independently an alkyl group or a group formed by bonding to each other because they are excellent in their own polymerizability or copolymerizability with an ethylenically unsaturated group-containing monomer. Groups forming a carbocycle are preferred. The alkyl group preferably has 4 or less carbon atoms. Furthermore, a group in which each is bonded to form a carbocyclic ring is preferable in that the production of the maleimide monomer is easy, the yield is excellent, and the obtained copolymer is excellent in water resistance. preferably, group -CH ₂ CH ₂ CH ₂ -, or a group -CH ₂ CH ₂ C
H ₂ CH ₂ — is preferred, particularly preferably the group —CH ₂ CH ₂
CH ₂ CH ₂ —.

As the maleimide monomer, a (meth) acrylate containing a maleimide group represented by the following (2) [hereinafter referred to as imide (meth) acrylate] is preferable.

[0014]

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However, in the formula (2), R ¹ and R ² are the same groups as described above. R ³ is an alkylene group, R ⁴ is hydrogen or a methyl group, and n is an integer of 1 to 6.

In the formula (2), those in which n is 1 to 2 are preferable, and those in which 1 is more preferable. R ³ preferably has 1 to 6 carbon atoms, and more preferably includes an ethylene group and a propylene group.

The imide (meth) acrylate can be produced from an acid anhydride, an amino alcohol and (meth) acrylic acid by the methods described in the following documents and patents. -Kiyoshi Kato et al., Journal of Synthetic Organic Chemistry, 30 (10), 89
7, (1972) Javier de Abajo et al., Polymer, vol 33
(5), (1992)-JP-A-56-53119, JP-A-1-2425
No. 69

1-2. Unsaturated Monomer As the component (A) in the present invention, a copolymer of a maleimide monomer and an unsaturated monomer is preferred because the resulting composition has a small curing shrinkage. . As the unsaturated monomer, various monomers can be used, but from the viewpoint of excellent physical properties of the coating film and copolymerizability with the maleimide monomer, alkyl (meth)
Acrylates are preferred.

As the alkyl (meth) acrylate, various compounds can be used, and any of a linear, branched or cyclic alkyl group can be used. Examples of the (meth) acrylate having a linear alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, and hexyl (meth) acrylate.
Acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate,
Examples include lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, and behenyl (meth) acrylate. The alkyl group of the monomer may contain an aromatic ring, oxygen, nitrogen, sulfur, halogen and the like. Such (meth) acrylates include benzyl (meth)
Acrylate, phenoxyethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, aminoethyl (meth)
Examples thereof include acrylate, chloroethyl (meth) acrylate, trifluoroethyl (meth) acrylate, and heptadecafluorooctylethyl (meth) acrylate.

As the (meth) acrylate having a branched alkyl group, isopropyl (meth) acrylate,
Isobutyl (meth) acrylate, s-butyl (meth)
Acrylate, t-butyl (meth) acrylate, neopentyl (meth) acrylate, ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, and isostearyl (meth) acrylate are exemplified. The alkyl group of the monomer may contain an aromatic ring, oxygen, nitrogen, sulfur, halogen and the like. Examples of such a monomer include 3-methoxybutyl (meth) acrylate, methoxytripropylene glycol (meth) acrylate, and hexafluoropropyl (meth) acrylate.

Examples of the (meth) acrylate having a cyclic alkyl group include cyclohexyl (meth) acrylate,
Examples include isobornyl (meth) acrylate and tricyclodecinyl (meth) acrylate. The alkyl group of the monomer may contain an aromatic ring, oxygen, nitrogen, sulfur, halogen and the like. Examples of such a monomer include tetrahydrofurfuryl (meth) acrylate (meth) acrylate and morpholinoethyl (meth) acrylate.

These alkyl (meth) acrylates are
They can be used alone or in combination.
In the present invention, among these alkyl (meth) acrylates, it is preferable that the alkyl (meth) acrylate has an alkyl group having 1 to 20 carbon atoms from the viewpoint of excellent hardness and weather resistance of the obtained coating film, and an alkyl group having 1 to 8 carbon atoms. It is particularly preferred to have Such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, ethylhexyl (meth) acrylate, and cyclohexyl (meth) Acrylates are exemplified.

As the unsaturated monomer, a functional group-containing monomer can be used. Examples of the functional group include a hydroxyl group, a carboxyl group, an epoxy group, and a hydrolyzable silyl group.

Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate; 2-hydroxychloropropyl (meth) Acrylates; polyalkylene glycol mono (meth) acrylates such as polyethylene glycol and polypropylene glycol mono (meth) acrylate, lactone-modified hydroxyethyl-modified (meth) acrylate, and containing hydroxyl groups
(Meth) acrylate oligomers and the like. The lactone-modified hydroxyethyl-modified (meth) acrylate is commercially available, and includes, for example, Placcel F series manufactured by Daicel Chemical Industries, Ltd. Hydroxyl-containing oligomers are commercially available, and are Alonix 5700 (trade name) manufactured by Toagosei Co., Ltd., which is an acrylate oligomer having a hydroxyl group at a terminal.
HE-10, HE-20, HP manufactured by Nippon Shokubai Chemical Industry Co., Ltd.
-10 and HP-20 (both are trade names).

Examples of the carboxyl group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid,
Vinyl acetic acid and crotonic acid;

The epoxy group-containing monomer includes (meth)
Glycidyl acrylate, allyl glycidyl ether, glycidyl vinyl ether and the like can be mentioned.

As the hydrolyzable silyl group-containing monomer,
Examples include trimethoxysilylpropyl (meth) acrylate, triethoxysilylpropyl (meth) acrylate, methyldimethoxysilylpropyl (meth) acrylate, and vinyltrimethoxysilane.

Examples of the unsaturated monomer include α-olefins such as ethylene, propylene and isobutylene; partially halogenated olefins such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride; And allyl compounds such as allyl butyrate, crotonic esters such as ethyl crotonate and propyl crotonate; vinyl ethers such as ethyl vinyl ether and cyclohexyl vinyl ether; vinyl carboxylate such as vinyl acetate, vinyl propionate and vinyl versatate; styrene, α-methyl Styrene such as styrene and vinyltoluene; acrylonitrile, acrylamide, and methacrylamide. These monomers are
Two or more types may be used in combination.

When the component (A) used in the present invention is a copolymer of a maleimide monomer and an unsaturated monomer, the copolymerization ratio of the monomer is 4 to 40 parts by mass of the maleimide monomer, It is preferable that the amount be 96 to 60 parts by mass of a saturated monomer. When the amount of the maleimide monomer is less than 4 parts by mass, the number of crosslinking points is small, and the curability and the performance of the cured coating film may be deteriorated.
The weather resistance may decrease.

In the coating composition of the present invention, the component (A) may be in any of a form dissolved in an organic solvent, a form non-aqueous dispersed in an organic solvent, and a form dispersed in water.

The average molecular weight of the component (A) is 1,000 to 100 as a number average molecular weight (hereinafter referred to as Mn) in terms of polystyrene by gel permeation chromatography.
Preferably it is 000. When the component (A) is used as an organic solvent-based paint and a non-aqueous dispersion paint dissolved in an organic solvent, Mn is preferably 3,000 to 100,000, while the component (A) is emulsified and suspended. When used as a dispersion in an aqueous medium, the Mn should be 10.0 or less.
It is preferably from 00 to 500,000.

The glass transition point (Tg) of the component (A) is preferably in the range of 5 ° C. to 80 ° C. Below 5 ° C,
The stain resistance of the coating film may decrease, and if it exceeds 80 ° C., the processability of the coating film may decrease.

1-3. Method for Producing Component (A) The component (A) can be produced by copolymerizing the above monomers in the presence of a radical polymerization initiator. As the polymerization method, bulk polymerization, suspension polymerization and emulsion polymerization in an aqueous medium,
A method such as solution polymerization in an organic solvent can be adopted. As a radical polymerization initiator, diisopropyl peroxydicarbonate, tert-butyl peroxypivalate,
Peroxides such as benzoyl peroxide and lauroyl peroxide, inorganic peroxides such as ammonium persulfate and potassium persulfate, and azo compounds such as azobisisobutyronitrile and azobisisovaleronitrile can be used. The amount used is 0.1 to the total monomer amount.
0001 to 10% by weight is preferred. In any polymerization, a chain transfer agent such as lauryl mercaptan may be added as necessary.

When the component (A) is produced by emulsion polymerization, as the emulsifier, an anionic type, a nonionic type and a combination thereof are preferable. Examples of anionic emulsifiers include sodium salts of higher alcohol sulfates, and examples of nonionic emulsifiers include polyethylene glycol alkyl ethers. In addition, a reactive emulsifier can also be used, and specifically, latemul (Kao Co., Ltd.), eleminol (Sanyo Chemical Co., Ltd.), Aqualon (Daiichi Kogyo Seiyaku Co., Ltd.) and Adecaria soap (Asahi Denka Kogyo Co., Ltd.) Co., Ltd.]. The amount of the emulsifier used is preferably in the range of 0.1 to 50 parts by mass based on 100 parts by mass of the total amount of the monomers. If necessary, potassium carbonate, sodium hydrogencarbonate, hydrotalcite, anion exchange resin and the like may be added as a pH adjuster.

When the component (A) is produced by solution polymerization, the organic solvent used includes cyclic ethers such as tetrahydrofuran and dioxane; hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene. Hydrogen compounds; acetates such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone and cyclohexanone; ethanol, isopropanol, n
Alcohols such as butanol and n-butyl cellosolve; and mineral spirits, naphtha No. 5 (aromatic content: 50% by mass) and naphtha No.
(Aromatic content 30% by mass) [All are trade names of Exxon Chemical Co., Ltd.], LAWS (Aromatic content 30% by mass), HAWS
(Aromatic content: 50% by mass) Hydrocarbon solvents such as Shell Chemical Co., Ltd. and Swazol 1000 (manufactured by Maruzen Oil Co., Ltd.). These organic solvents can be used in combination of two or more kinds. The amount of the organic solvent used is 20 to 200 parts by mass based on 100 parts by mass of the total monomers.
It is preferably in the range of parts.

When the component (A) is produced by non-aqueous dispersion polymerization,
The monomer having a composition insoluble in the solvent is copolymerized in the presence of a polymer soluble in the solvent such as a long-chain alkyl (meth) acrylate copolymer in a hydrocarbon solvent. Examples of the hydrocarbon solvent used in this case include those described above.

The polymerization conditions are not particularly limited.
The preferred polymerization temperature in the preferred reaction is 20-140 ° C
Yes, usually at normal pressure. Suitable polymerization times are from 3 to
40 hours. The monomers used for the polymerization may be initially batch-charged in their entirety, or some of the monomers may be added sequentially as the polymerization proceeds.

2. Component (B) As the pigment of the component (B), various pigments usually used in paints can be used. Specifically, titanium oxide, red iron oxide, yellow iron oxide, calcined pigments, inorganic pigments such as pearl pigments and mica pieces, phthalocyanine blue, quinacridone red, perylene, isoindolinone, organic pigments such as irgazine yellow and carbon black, Volume pigments such as calcium carbonate and barium sulfate; and metallic pigments such as aluminum powder, stainless steel powder and bronze powder. or,
(B) component, it is also possible to use a matting agent together,
Examples include polyethylene wax, polypropylene wax, and silica-based matting agents. The amount of component (B) used is
The amount may be appropriately determined depending on the components used, the purpose, and the like, but is preferably 1 to 100 parts by mass per 100 parts by mass of the component (A).

3. (C) Photosensitizer and / or Photopolymerization Initiator The composition of the present invention contains (C) a photosensitizer and / or a photopolymerization initiator. The composition of the present invention is a composition in which the maleimide groups in the component (A) are cross-linked by a photoreaction by sunlight to improve the physical properties of the resulting coating film. The crosslinking reaction can be promoted even if it is included. As the specific examples of the component (C), various ones can be used, and hydrocarbon sensitizers such as naphthalene and phenanthrene; nitrobenzene, p
Nitrobenzene derivatives such as dinitrobenzene and p-nitroaniline; acetophenone, propiophenone,
Benzophenone, [4- (methylphenylthio) phenyl] phenylmethane, benzaldehyde, 3-methylacetophenone, 4-methylacetophenone, 3-pentylacetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-allylacetophenone, p-
Diacetylbenzene, 3-methoxybenzophenone, 4
-Methylbenzophenone, 4-chlorobenzophenone,
4,4′-dimethoxybenzophenone, 1,1′-dimethoxy-1-phenylbenzophenone, 4-chloro-
4'-benzylbenzophenone, p, p'-diethylaminobenzophenone, p, p'-diethylaminobenzophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, bis (4-dimethylaminophenyl ) Benzphenone and acetophenone derivatives such as ketone, bis (4-diethylaminophenyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinoether) butanone-1; isobutyl benzoin ether, isopropyl benzoin ether, benzoin Benzoin ethers such as ethyl ether and benzoin methyl ether; 2,2-
Dimethoxy-1,2-diphenylethan-1-one, 1
-Benzyl ketals such as hydroxycyclohexyl phenyl ketone and benzyl; 3-chloroxanthone, 3,
Xanthones such as 9-dichloroxanthone, 3-chloro-8-nonylxanthone, 2-chlorothioxanthone and 2,4-diethylthioxanthone; bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine Acyl phosphine oxides such as oxide and bis (2,4,6-trimethylbenzoyl) phenyl phosphine oxide; benzoyl, benzoin methyl ether, benzoin butyl ether, benzyl methoxy ketal, ethyl anthraquinone and the like. Among them, benzophenones, acetophenones, xanthones and acylphosphine oxides are preferred, and xanthones are most preferred. (C)
The components may be used alone or in combination of two or more. The amount of the component (C) to be used is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the component (A). If the amount is less than 0.1 part by mass, curing may be insufficient, and if it exceeds 10 parts by mass, discoloration may occur in the coating film.

4. Other Components The composition of the present invention essentially comprises the components (A) to (C). Depending on the amount of the component (C) used, the coating film may gradually change its color. May be. As a method for preventing this, it is preferable to add a radical scavenger and / or a compound having a peroxide decomposing action. These components can suppress discoloration and do not reduce the curing speed even when added.

As the radical scavenger, a hindered amine compound usually known as a light stabilizer is preferable.
Specifically, bis (2,2,6,6-tetramethyl-4-
Piperidyl) sebacate, bis (1,2,2,6,6-
Pentamethyl-4-piperidyl) sebacate, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-
1,3,8-Triazaspiro (4,5) decane-2,4
-Dione, bis (N-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl)-
Examples thereof include 1,2,3,4-butanetetracarboxylate and tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate.

Examples of the compounds having a peroxide decomposing action include amines, sulfur antioxidants, compounds containing a mercapto group and compounds containing an isocyanate group. As amines, primary amines such as ethylamine, propylamine, isopropylamine, butylamine, hexylamine, heptylamine, cyclohexylamine, aniline, hexamethylenediamine and ethylenediamine; dimethylamine, diethylamine, diisopropylamine and dibutylamine; Secondary amines such as morpholine; tertiary amines such as triethylamine, tributylamine and triisopropylamine; hydroxyl-containing amines such as ethanolamine and diethanolamine; and aminomethyltriethoxysilane, N
Containing amino groups such as -β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane and γ-dibutylaminopropyltrimethoxysilane Examples include a silane coupling agent. As the sulfur-based antioxidants, dilauryl-3,
3'-thiodipropionate, ditridecyl-3,3'-
Thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, pentaerythrityl-tetrakis (3-
Lauryl thiopropionate), bis {2-methyl-4
-(3-n-C12 or C14 alkylthiopropionyloxy) -5-tert-butylphenyl disulfide, 2-mercaptobenzimidazole and the like.
Examples of the mercapto group-containing compound include mercaptans such as mercaptoethanol, dodecylmercaptan and laurylmercaptan, and silane coupling agents having a mercapto group such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane. Examples of the isocyanate group-containing compound include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; cycloaliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate and 1,3-bis (isocyanatomethyl) cyclohexane; And aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate. Further, those obtained by adding these isocyanates to a polyhydric alcohol, a nurate-type multimer of these isocyanates, a burette and the like are used. Also, an isocyanate group-containing silane coupling agent or the like can be used.

The radical scavenger and the compound having a peroxide decomposing action may be used alone or in combination of two or more. The amount of the radical scavenger and / or the compound having a peroxide decomposition action to be used is preferably 0.1 to 10 parts by mass per 100 parts by mass of the component (A).

When the composition of the present invention is an organic solvent type coating material, the organic solvent used preferably has a boiling point of 60 ° C. or higher. When an organic solvent having a boiling point of less than 60 ° C. is used, when a coating material is used, drying may be too fast and film forming properties may be reduced. The organic solvent used in the polymerization reaction can be used as it is or can be added later. Specific examples of the organic solvent include, in addition to those mentioned as examples of the organic solvent in the solution polymerization of the above section 1-3, ortho acids such as methyl orthoformate and methyl orthoacetate; ethylene glycol monobutyl ether and diethylene glycol mono Cellosolve or carbitol solvents such as butyl ether; alkylene glycol alkyl ethers such as propylene glycol methyl ether and propylene glycol butyl ether; isoprene such as 3-methoxy-3-methyl-1-butanol and 3-methyl-3-methoxybutyl acetate Glycol-based solvents and the like. When the composition of the present invention is a non-aqueous dispersion type paint,
As the organic solvent to be used, mineral spirit, naphtha No. 5, naphtha No. 6, LAWS, HAWS and the like are preferable. The ratio of the organic solvent in the organic solvent type paint is as follows: Component (A): organic solvent = 25: 75 to 75:25
(Mass ratio) is preferred.

When the composition of the present invention uses the component (A) emulsified or dispersed in an aqueous medium, an organic solvent may be added as necessary. As the organic solvent in this case, ethanol, ethylene glycol, 3-methoxy-3-methyl-1-butanol, 3-methyl-3-methoxybutyl acetate, 2,2,4-trimethyl-1,
Cellosolve or carbitol solvents such as 3-pentanediol monoisobutyrate, ethylene glycol monobutyl ether and diethylene glycol monobutyl ether; and organic solvents such as alkylene glycol alkyl ethers such as propylene glycol methyl ether and propylene glycol butyl ether. The ratio of water in the emulsified or dispersed type paint in the aqueous medium is as follows: component (A): water = 30: 70 to 60:40 (mass ratio)
Is preferred.

The composition of the present invention may further contain additives such as a dispersant, an ultraviolet absorber, a surface conditioner, and a thickener. Further, an alkyl silicate or an alkyl silicate oligomer can be added to improve the stain resistance. The composition of the present invention can be used as a one-pack type outdoor coating composition. The composition of the present invention can be applied to various substrates. Specifically, steel plate,
Examples include stainless steel, aluminum, concrete, mortar, plastic and wood. The method of use may be in accordance with a conventional method, and the substrate can be coated directly or via a primer with a spray, brush, roll, bar coater or the like.

[0047]

The present invention will be described more specifically below with reference to examples and comparative examples. In the following, "%" means% by mass.

Preparation of Pigment Dispersion Copolymer (T-1, Tg: 34 ° C.) prepared using monomers of the type and ratio shown in Table 1 below as component W-1 (A)
Mn: 16000) was used. Using the solution of T1 and each component shown in Table 2, using a high-speed stirrer, each component was stirred and mixed according to a conventional method to prepare a white dispersion (W-1).

W-2: A copolymer (T-2, Tg: 20 ° C., produced using monomers of the types and ratios shown in Table 1 below as the component (A)
Mn: 13000) using a 50% butyl acetate solution,
Using the components shown in Table 2, a white dispersion (W-2) was prepared in the same manner as in W-1.

W-3 Copolymer (T-3, Tg: 27 ° C., obtained using monomers of the types and ratios shown in Table 1 below as component (A)
A white dispersion (W-3) was prepared in the same manner as in W-1 using a 50% HAWS solution (Mn: 15000) and the components shown in Table 2.

W-4 As a component (A), monomers of the types and ratios shown in Table 1 below are used, and as an emulsifier, Aqualon HS which is a reactive emulsifier is used.
10 [Daiichi Kogyo Seiyaku Co., Ltd.] and an aqueous dispersion (solid content: 45%) of the copolymer (T-4) produced by emulsion polymerization.
%)It was used. Using the components shown in Table 2, a white dispersion (W-4) was prepared in the same manner as in W-1.

[0052]

[Table 1]

The abbreviations in Table 1 have the following meanings. THPI: imide acrylate represented by the following formula (3)

[0054]

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DMMI: imide acrylate represented by the following formula (4)

[0056]

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CHA: cyclohexyl acrylate MMA: methyl methacrylate BMA: butyl methacrylate IBMA: isobutyl methacrylate BA: butyl acrylate EHMA: 2-ethylhexyl methacrylate HEMA: hydroxyethyl methacrylate ST: styrene AA: acrylic acid MAA: methacrylic acid

[0058]

[Table 2]

Examples 1 to 6 The components shown in Table 3 were used, and the components were mixed to prepare a coating composition. The obtained composition was evaluated according to the evaluation method described below.

[0060]

[Table 3]

1) DETX-S: Photosensitizer, Nippon Kayaku
KAYACURE DETX-S, manufactured by 20% solfit acetate solution of 2,4-diethylthioxanthone 2) CTX: photosensitizer, KAYACUR manufactured by Nippon Kayaku Co., Ltd.
ECTX, 20% solfit acetate solution of 2-chlorothioxanthone 3) Ir819: Photopolymerization initiator, Irgacure 819 manufactured by Ciba Specialty Chemical Co., Ltd., bis (2,
4,6-trimethylbenzoyl) phenylphosphine oxide in 20% xylene solution 4) TV292: light stabilizer, Ciba Specialty
Chemicals Co., Ltd. Tinuvin 292, bis (1, 2, 2,
6,6-Pentamethyl-4-piperidyl) sebacate 20% solfit acetate solution 5) DM: dodecyl mercaptan xylene 20% solution

Comparative Examples 1 and 2 A coating composition was prepared in the same manner as in the Examples, using the components shown in Table 4. The obtained composition was evaluated according to the evaluation method described below.

[0063]

[Table 4]

Evaluation: Curable Each composition was applied to a tin plate using a bar coater (dry film thickness: about 30 μm). Two hours after the coating, the coated plate was taken out, placed at 45 ° on the south side and 45 ° on the north side, and dried. Three days, one week and two weeks later, a xylene rubbing test was performed to determine the degree of curing. ：: almost no insoluble portion, Δ: soluble portion, Δ ×: insoluble only on the surface, ×: almost dissolved The results obtained are shown in Table 5.

[0065]

[Table 5]

Other Evaluations Each composition was applied to a 5052P aluminum plate using a bar coater (dry film thickness: about 30 μm). The coated plate half a day after the coating was taken out, placed at 45 ° on the south side, dried, and one week later was used as a test plate, and the following items were evaluated.
Table 6 shows the obtained results.

1) Degree of Discoloration The hue half a day after coating was measured by Lab value. One week after drying, the Lab of the test plate was measured, and its color difference ΔE was calculated.

2) Gloss at 60 ° Measured according to JIS-K5400.

3) Pencil hardness Measured according to JIS-K5400.

4) Weather resistance 60 days after 1000 hours of sunshine weather meter test
The gloss retention (%) and the color difference ΔE were calculated.

5) Alkali resistance One drop of a 5% aqueous NaOH solution was dropped on the surface of the coating film, washed with water after 8 hours, dried, and the surface of the coating film was observed. ○: No abnormality ×: Trace remains

6) Acid resistance One drop of a 5% sulfuric acid aqueous solution was dropped on the surface of the coating film, washed with water after 8 hours, dried, and the surface of the coating film was observed. ○: No abnormality ×: Trace remains

[0073]

[Table 6]

[0074]

The composition of the present invention can be easily applied as a one-pack type paint, and even if it is a colored paint containing a pigment, the curing reaction proceeds to the deep part of the coating film due to sunlight, and the resulting coating composition is obtained. The film becomes excellent in weather resistance, solvent resistance and chemical resistance.

Continued on the front page F term (reference) 4J038 CG141 CH191 CJ011 CJ031 CJ061 CJ091 CJ131 CJ181 CK021 GA01 GA08 JB01 JC01 JC02 KA02 KA03 KA08 NA03 NA04 PA17 PB05 PC02 PC04 PC08

Claims (3)

[Claims] 1. An outdoor coating composition comprising (A) a polymer having a maleimide group, (B) a pigment and (C) a photosensitizer and / or a photopolymerization initiator as essential components. 2. The outdoor coating composition according to claim 1, wherein the maleimide group of the component (A) is represented by the following formula (1). Embedded image (However, in the formula (1), R ¹ and R ² are each independently a hydrogen atom or an alkyl group, one of them is a hydrogen atom and the other is an alkyl group, or a group each forming a carbon ring by bonding. is there.) 3. The composition for outdoor paint according to claim 1, further comprising a radical scavenger and / or a compound having a peroxide decomposing action.