JP2011252078A - Ultraviolet-curing coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet-curing coating composition which can provide a coating film having good adhesiveness to a base material, such as a metal and plastic, that has poor adhesiveness in a conventional ultraviolet-curing coating material.SOLUTION: The ultraviolet-curing coating composition comprises: an acrylic resin (A) having a first functional group selected from an amino group, hydroxyl group, carboxyl group, epoxy group and isocyanate group; an alkoxysilane compound (B) having a second functional group reacting with the first functional group; an ultraviolet-curing compound (C); and a polymerization initiator.

Description

  The present invention relates to an ultraviolet curable coating composition.

Conventionally, ultraviolet curable coatings have been used for the purpose of improving the corrosion resistance of various substrates and improving the scratch resistance of their surfaces.
This ultraviolet curable coating generally has a drawback of poor adhesion to plastics and metals because of its large cure shrinkage.

For this reason, when an ultraviolet curable coating is used for a substrate made of a material such as plastic or metal, generally, after applying various primer treatments to the substrate surface, the ultraviolet curable coating is applied. It has been broken.
In addition, a thermosetting paint containing a phenol resin, an epoxy resin, a melamine resin or the like excellent in adhesion is often used for a base material made of these materials.

However, in the method of applying the UV curable paint after applying the primer treatment, the number of processes increases, so that not only the productivity, which is one of the advantages of the UV curable paint, is reduced, but also the cost is increased. was there.
In addition, when a thermosetting resin such as a phenol resin is used, there is a problem that, since a certain amount of time is required for curing, the productivity is lowered and the hardness of the obtained film is insufficient.

As means for solving these problems, Patent Document 1 discloses a technique using an ultraviolet curable coating material mainly composed of a benzyl group-containing acrylate oligomer.
By using this paint, it is possible to form a film with good adhesion to some extent even for plastics and metals for which sufficient adhesion was not obtained with conventional UV curable paints. In that respect, there was room for further improvement.

JP 2009-57525 A

  The present invention has been made in view of such circumstances, and UV curing capable of providing a coating film having good adhesion to substrates such as metals and plastics that have poor adhesion with conventional ultraviolet curable paints. An object of the present invention is to provide a mold coating composition.

  As a result of intensive studies in order to achieve the above object, the present inventors have found that an acrylic resin having a first functional group such as an amino group or a hydroxyl group, a second reactive group having reactivity with the first functional group. Finding that a coating obtained from a composition containing an alkoxysilane compound having a functional group, an ultraviolet curable compound, and a photopolymerization initiator has good adhesion to a metal or the like, and using the composition Thus, it was found that a coating having excellent adhesion to a substrate such as metal can be formed with one coat, and the present invention was completed.

That is, the present invention
1. (A) an acrylic resin having a first functional group selected from an amino group, a hydroxyl group, a carboxyl group, an epoxy group, and an isocyanate group; and (B) a second functional group having reactivity with the first functional group. An alkoxysilane compound having (C) an ultraviolet curable compound, and (D) a photopolymerization initiator, wherein the (C) ultraviolet curable compound is contained in a total solid content of 10 to 80% by mass. UV curable coating composition,
2. (1) the ultraviolet curable coating composition in which the acrylic resin (A) has an amino group and / or a hydroxyl group;
3. (2) the ultraviolet curable coating composition in which the acrylic resin (A) has both an amino group and a hydroxyl group;
4). 2 or 3 UV curable coating composition, wherein the amino group is a tertiary amino group,
5). The ultraviolet curable coating composition according to any one of 2 to 4, wherein the (A) acrylic resin has a total of 10 mgKOH / g or more of the amino group and / or hydroxyl group,
6). The ultraviolet curable coating composition according to any one of 2 to 4, wherein the (B) alkoxysilane compound has an epoxy group and / or an isocyanate group,
7). Silicon atoms, or an ultraviolet-curable coating composition of claims 1-6 contained 0.05% by mass or more in total solids in terms of SiO _2,
8). A coated product comprising a substrate and a coating directly formed on the surface of the substrate, wherein the coating is formed from any one of compositions 1 to 7;
9. Nine coated products are provided in which the substrate comprises a metal or metal oxide.

ADVANTAGE OF THE INVENTION According to this invention, the ultraviolet curable coating composition which can provide the film excellent in adhesiveness with respect to the base material with poor adhesiveness in the conventional ultraviolet curable coating materials, such as a metal and a plastics, can be provided.
That is, by using the ultraviolet curable coating composition of the present invention, a coating film having excellent adhesion to metals and the like can be formed in one coat without primer treatment.
Such an ultraviolet curable coating composition of the present invention includes, for example, cold-rolled steel sheet, galvanized steel sheet, alloyed galvanized steel sheet, tin-plated steel sheet, chrome-plated steel sheet, aluminum-plated steel sheet, lead-plated steel sheet, nickel-plated steel sheet, It can be directly applied to an aluminum plate, a titanium plate, a magnesium alloy plate, a stainless steel plate or the like.

Hereinafter, the present invention will be described in more detail.
The ultraviolet curable coating composition according to the present invention includes (A) an acrylic resin having a first functional group, (B) an alkoxysilane compound having a second functional group reactive with the first functional group, C) contains an ultraviolet curable compound, and (D) a photopolymerization initiator.

(A) Acrylic resin In the ultraviolet curable coating composition of the present invention, an acrylic resin having a first functional group is used.
Here, examples of the first functional group of the acrylic resin include at least one selected from an amino group, a hydroxyl group, a carboxyl group, an epoxy group, and an isocyanate group. Considering further enhancement, the acrylic resin used in the present invention preferably has at least one of an amino group and a hydroxyl group, and preferably has both an amino group and a hydroxyl group. The amino group may be primary, secondary, or tertiary, but a tertiary amine is particularly preferable.
The content of the amino group and the hydroxyl group is not particularly limited, but in consideration of further improving the adhesion of the resulting coating to the substrate, the total of the amino group and the hydroxyl group may be 10 mgKOH / g or more. Preferably, it is preferably 12 mgKOH / g or more, and more preferably 20 mgKOH / g or more.

The acrylic resin having the functional group can be obtained, for example, by radical polymerization of an acrylic monomer having a functional group.
Examples of amino group-containing acrylic monomers include aminoethyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, 2-dimethylaminopropyl (meth) acrylate, t-butylaminopropyl (meth) acrylate, and dimethylamino. Examples thereof include propyl (meth) acrylamide and dimethylaminoethyl (meth) acrylate.
Examples of the hydroxyl group-containing acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl. Examples include (meth) acrylate, N-methylol acrylamide, ε-caprolactone-modified hydroxy (meth) acrylate, carbonate-modified methacrylate (manufactured by Daicel Chemical Industries, Ltd., HEMAC).
Examples of the epoxy group-containing acrylic monomer include glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, glycidyl ether of 4-hydroxybutyl (meth) acrylate, and the like.
Examples of the isocyanate group-containing acrylic monomer include 2-isocyanatoethyl (meth) acrylate, 3-isocyanatopropyl (meth) acrylate, 2-isocyanato-1-methylethyl (meth) acrylate, 2-isocyanato-1, Examples thereof include 1-dimethylethyl (meth) acrylate and 4-isocyanatocyclohexyl (meth) acrylate.
As the carboxyl group-containing acrylic monomer, for example, a terminal hydroxyl group of an acrylic monomer containing acrylic acid, methacrylic acid, or a hydroxyl group is reacted with an acid anhydride such as an aliphatic dicarboxylic acid such as succinic anhydride or glutaric anhydride. Examples thereof include compounds obtained.

In the production of the acrylic resin of the present invention, other monomers copolymerizable with the acrylic monomer having the first functional group may be used.
Specific examples of other copolymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and cyclohexyl. Alkyl group-containing (meth) acrylic monomers such as (meth) acrylate; Amide group-containing (meth) acrylic monomers such as (meth) acrylamide and ethyl (meth) acrylamide; Nitrile group-containing (meth) acrylic monomers such as acrylonitrile Aromatic hydrocarbon vinyl monomers such as styrene, methylstyrene, chlorostyrene and vinyltoluene; α, β-ethylenically unsaturated carboxylic acids such as maleic acid, itaconic acid, crotonic acid, fumaric acid and citraconic acid; styrenesulfone Acid, vinyl sulfone Sulfonic acid-containing vinyl monomers such as acids; unsaturated bond-containing acid anhydrides such as maleic anhydride and itaconic anhydride; chlorine-containing monomers such as vinyl chloride, vinylidene chloride and chloroprene; hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether Hydroxyl-containing alkyl vinyl ethers such as ethylene glycol monoallyl ether, propylene glycol monoallyl ether, diethylene glycol monoallyl ether and other alkylene glycol monoallyl ethers; ethylene, propylene, isobutylene and other α-olefins; vinyl acetate, vinyl propionate, Carboxylic acid vinyl esters such as vinyl butyrate and vinyl pivalate; methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, Vinyl ethers such as hexyl vinyl ether, ethyl allyl ether, include allyl ethers such as butyl ether, it may be used singly or may be used in combination of two or more.
When a monomer having a functional group corresponding to the first functional group, such as a hydroxyl group-containing alkyl vinyl ether, is used, an acryl having the first functional group is copolymerized with the alkyl group-containing (meth) acrylic monomer. It can also be a resin.

The above polymerization is carried out using a radical polymerization initiator in the presence of a suitable organic solvent.
Any organic solvent may be used as long as it does not adversely influence the reaction. For example, aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, n-octane, cyclohexane and cyclopentane; toluene, Aromatic hydrocarbons such as xylene, ethylbenzene, low boiling aromatic naphtha, high boiling aromatic naphtha, etc .; ethyl acetate, n-butyl acetate, n-amyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol Monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 3 Esters such as methoxybutyl acetate; methanol, ethanol, i-propanol, n-butanol, i-butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, propylene glycol monomethyl ether, propylene glycol mono Alcohols such as n-propyl ether and diethylene glycol monobutyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone and cyclohexanone; dimethoxyethane, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol Dimethyl ether, diethylene glycol Ethers such as butyl ether; N- methylpyrrolidone, dimethylformamide, dimethylacetamide, ethylene carbonate, and the like. These may be used alone or in combination of two or more.

The radical polymerization initiator can be appropriately selected from known ones such as 2,2′-azobisisobutyronitrile, azobisisovaleronitrile, benzoyl peroxide, t-butyl peroxide, cumene hydro A peroxide etc. are mentioned. These may be used alone or in combination of two or more.
The reaction temperature is usually about 60 to 100 ° C. The reaction time is usually about 1 to 12 hours.

Although content of the acrylic resin in a composition is not specifically limited, 10-75 mass is preferable in a total solid, and 20-75 mass% is preferable.
The molecular weight of the acrylic resin used in the present invention is not particularly limited, but a number average molecular weight of 3,000 to 100,000 is preferable.
The number average molecular weight is a value measured by gel permeation chromatography (hereinafter abbreviated as GPC) by differential refractometer detection (polystyrene conversion value).

(B) Alkoxysilane Compound In the composition of the present invention, an alkoxysilane compound having a second functional group reactive with the first functional group of the acrylic resin described above is used.
In this case, the number of alkoxy groups in the alkoxysilane may be any of 1 to 3, but 3 is preferable in consideration of improving the adhesion of the resulting coating film to metal or the like.
Examples of the alkoxysilane compound having such a second functional group include the following.
(1) Epoxy group-containing alkoxysilane glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, 1-glycidoxyethyltrimethoxysilane, 1-glycidoxyethyltriethoxysilane, 2-glycidoxyethyl Trimethoxysilane, 2-glycidoxyethyltriethoxysilane, 2-glycidoxypropyltrimethoxysilane, 2-glycidoxypropyltriethoxysilane, 2-glycidoxypropyltrimethoxysilane, 2-glycidoxypropyl Triethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltriisopropoxysilane, 3-glycidyl Sidoxypropi Lultriboxysilane, 3-glycidoxypropyltri (methoxyethoxy) silane, 1-glycidoxybutyltrimethoxysilane, 1-glycidoxybutyltriethoxysilane, 2-glycidoxybutyltrimethoxysilane, 2-glycidyl Sidoxybutyltriethoxysilane, 3-glycidoxybutyltrimethoxysilane, 3-glycidoxybutyltriethoxysilane, 4-glycidoxybutyltrimethoxysilane, 4-glycidoxybutyltriethoxysilane, (3 4-epoxycyclohexyl) methyltrimethoxysilane, (3,4-epoxycyclohexyl) methyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltripropoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri Butoxysilane, 2 (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriphenoxysilane, 3- (3,4 Epoxycyclohexyl) propyltrimethoxysilane, 3- (3,4-epoxycyclohexyl) propyltriethoxysilane, 4- (3,4-epoxycyclohexyl) butyltrimethoxysilane, 4- (3,4-epoxycyclohexyl) butyltri Ethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, glycidoxymethyldimethoxysilane, glycidoxymethylmethyldiethoxysilane, 1-glycidoxyethylmethyldimethoxysilane, 1-glycidoxyethylmethyldiethoxysilane 2-glycidoxyethylmethyldimethoxysilane, 2-glycidoxyethylmethyldiethoxysilane, 1-glycidoxypropylmethyldimethoxysilane, 1-glycidoxypropylmethyldiethoxysilane, 2-glycidoxypropylmethyl Dimethoxysilane, 2-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldipropoxysilane, 2-glycid Xylpropylmethyldibutoxysilane, 3-glycidoxypropylmethyldimethoxyethoxysilane, 3-glycidoxypropylethyldimethoxysilane, 3-glycidoxypropylethyldiethoxysilane, etc.

(2) Isocyanate group-containing alkoxysilane 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyldimethoxymethylsilane, 3-isocyanatopropylmethoxydimethylsilane, 3-isocyanatopropyltriethoxysilane 3-isocyanatopropyldiethoxyethylsilane, 3-isocyanatopropylethoxydiethylsilane, 6-isocyanatohexyltrimethoxysilane, 6-isocyanatohexyldimethoxymethylsilane, 6-isocyanatohexylmethoxydimethylsilane, 6-isocyanate Natohexyltriethoxysilane, 6-isocyanatohexyldiethoxyethylsilane, 6-isocyanatohexylethoxydiethylsilane Moreover, you may use what was manufactured by the method disclosed by Unexamined-Japanese-Patent No. 9-328489 as such an isocyanate group containing alkoxysilane.

Furthermore, as the isocyanate group-containing alkoxysilane, an isocyanate group-containing urethane, urea, or thiourethane-modified alkoxysilane obtained by reacting a polyisocyanate with a hydroxyl group, amino group, or mercapto group-containing alkoxysilane compound may be used.
In this case, as the polyisocyanate, TDI TMP adduct, TDI isocyanurate, HDI burette, IPIDI isocyanurate, etc., and commercially available Takenate D-110N (manufactured by Mitsui Chemicals), Coronate HX (Nippon Polyurethane Industry Co., Ltd.) etc. are mentioned.
Examples of the hydroxyl group-containing alkoxysilane include 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, and 3-hydroxypropyltriethoxysilane.
Examples of the amino group-containing alkoxysilane include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, and N-2 (aminoethyl) 3-aminopropyl. Triethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3- (N, N-diglycidyl) aminopropyltrimethoxysilane (also applicable to epoxy group-containing alkoxysilane), 3-aminopropylmethyldimethoxysilane, Examples include 3-aminopropylmethyldiethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane.
Examples of the mercapto group-containing alkoxysilane include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

(3) Amino group-containing alkoxysilane Examples of the amino group-containing alkoxysilane include those described above.
The alkoxysilane having each functional group described above may be used alone or in combination of two or more. When two or more types are used in combination, a combination having the same functional group or a combination having different functional groups may be used.

Among the above functional group-containing alkoxysilanes, isocyanate group-containing alkoxysilanes are preferred from the viewpoint of enhancing the flexibility of the resulting coating, and isocyanate group-containing urethane, urea, or thiourethane-modified alkoxysilanes are more preferred. .
The content of the functional group-containing alkoxysilane in the composition is not particularly limited, but considering that the adhesion of the resulting coating to metals and the like is further increased, the silicon atoms are total solids in terms of SiO _2. The amount contained in the minute is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and even more preferably 0.20% by mass or more.
The upper limit is not particularly limited, but is preferably about 3.0% by mass.

(C) Ultraviolet curable compound In the composition of the present invention, an ultraviolet curable compound is used.
The ultraviolet curable compound is not particularly limited as long as it has an unsaturated double bond that is polymerized by a photopolymerization initiator, and may be appropriately selected from conventionally known ultraviolet curable monomers and oligomers. it can.
Specific examples include dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, nonylphenoxytetraethylene glycol (meth) acrylate, and nonanediol di (meth) acrylate. , Alkoxypolyalkylene glycol (meth) acrylates such as pentamethylpiperidyl (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate; glycerol (meth) acrylate, polyethylene glycol (meth) acrylate, Hydroxyl group-containing (meth) acrylates such as polypropylene glycol (meth) acrylate; neopentyl glycol di (meth) acrylate Alkylene glycol di (meth) acrylates such as polyethylene glycol di (meth) acrylate; glycerin propylene oxide modified tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide modified tri (meth) acrylate, trimethylol Trifunctional (meth) acrylates such as propanepropylene oxide modified tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate tripropionate; pentaerythritol tetra (meth) acrylate, dipentaerythritol Penta (meth) acrylate monopropionate, dipentaerythritol hexa (meth) acrylate, tetramethylo Multifunctional (meth) acrylates such as rumethanetetra (meth) acrylate, oligoestertetra (meth) acrylate, tris ((meth) acryloyloxy) phosphate, hexamethacryloyloxyethoxycyclotriphosphazene (PPZ), and commercially available Urethane acrylate (UV-6300B manufactured by Nippon Synthetic Chemical Industry Co., Ltd., RA-1353 manufactured by Mitsui Chemicals Co., Ltd.), polyester acrylate (EBECRYL 405 manufactured by Daicel Cytec Co., Ltd., DIC V-3021 etc.), Examples include epoxy acrylate (EBECRYL 600 manufactured by Daicel Cytec Co., Ltd., V-5500 manufactured by DIC Co., Ltd.), and the like.

  The content of the ultraviolet curable compound in the composition is such that the greater the content, the lower the flexibility of the resulting coating and the adhesion to the substrate, and the lower the content, the surface hardness of the resulting coating and the substrate. Since adhesiveness will become low, when considering making these into an appropriate range, 10-80 mass% is preferable in a total solid, 12-75 mass% is preferable, and 15-75 mass% is more preferable.

(D) Photopolymerization initiator The composition of the present invention uses a photopolymerization initiator that generates radicals upon irradiation with ultraviolet rays.
The photopolymerization initiator is not particularly limited, and examples thereof include benzoin or benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; aromatic ketones such as benzophenone and benzoylbenzoic acid. Α-dicarbonyls such as benzyl; benzyl ketals such as benzyl dimethyl ketal and benzyl diethyl ketal; acetophenone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxy Cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methyl-propan-1-one, 2-methyl -1- [4 Acetophenones such as (methylthio) phenyl] -2-morpholinopropanone-1; anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone; 2,4-dimethylthioxanthone, 2-isopropylthioxanthone Thioxanthones such as 2,4-diisopropylthioxanthone; α-acyloximes such as 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime; ethyl p-dimethylaminobenzoate, p- And amines such as isoamyl dimethylaminobenzoate.
In addition, as a photopolymerization initiator, Irgacure 184, 1000, 1700 (above, manufactured by Ciba Specialty Chemicals); Lucirin LR8728 (manufactured by BASF, trade name); Darocur 1116, 1173 (manufactured by Merck, Inc.) Name); Ubekrill P36 (trade name, manufactured by UCB) can also be used.
The amount of the photopolymerization initiator used is not particularly limited as long as it is an effective amount or more, but is usually about 0.1 to 10% by mass in the total solid content of the composition.
The composition of the present invention contains various additives such as an antifoaming agent, a thickener, an anti-settling agent, an ultraviolet absorber, a light stabilizer, and a catalyst as long as the effects of the present invention are not impaired. Also good.

The composition of the present invention can be prepared by appropriately orienting the above components in any order, and a solvent may be used in the preparation.
Examples of the solvent include aromatic hydrocarbon solvents such as toluene and xylene; ester solvents such as ethyl acetate, n-butyl acetate and n-amyl acetate; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; cyclohexane, methylcyclohexane and ethyl Cycloaliphatic hydrocarbon solvents such as cyclohexane; petroleum hydrocarbon solvents such as mineral spirits; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether pro Pionate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, glycol ether Ether ester solvent, and the like. These solvents may be used alone or in combination of two or more.
Although there is no restriction | limiting in particular in the usage-amount of a solvent, The quantity from which the total solid content in a composition will be about 10-70 mass% is preferable.

Examples of the method of using the ultraviolet curable coating composition described above include a method in which the composition of the present invention is directly applied to the surface of a substrate, heated and dried, and then irradiated with ultraviolet rays.
In this case, the coating method of the composition of the present invention is not particularly limited, and may be appropriately selected from known methods such as brush coating and roller coating. Moreover, what is necessary is just to make an application quantity, the thickness of a coating film, drying time, etc. suitable according to the material of a base material, the use of a coated article, etc.
The heating and drying temperature is such that (A) the first functional group of the acrylic resin and (B) the second functional group of the alkoxysilane compound react and the alkoxysilane compound undergoes (partial) hydrolysis condensation. Although it will not specifically limit if it is a temperature range, 50-100 degreeC is preferable in this invention, and 60-80 degreeC is more preferable.

The substrate to which the composition of the present invention is applied is arbitrary, but in particular, the conventional ultraviolet curable coating composition exhibits good adhesion even to a substrate made of a material having poor adhesion.
Examples of such a substrate include a metal substrate, a plastic substrate, and a glass substrate.
As the metal substrate, cold rolled steel sheet, galvanized steel sheet, alloyed galvanized steel sheet, tin plated steel sheet, chrome plated steel sheet, aluminum plated steel sheet, lead plated steel sheet, nickel plated steel sheet, aluminum plate, magnesium alloy plate, titanium plate, Examples include stainless steel plates.
Examples of the plastic substrate include ABS resin, polycarbonate, acrylic resin, polystyrene, MS resin, polybutylene terephthalate, polyethylene terephthalate, polyphenylene sulfide, and triacetyl cellulose.

Hereinafter, although a synthesis example, an Example, and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example. In addition, each physical property in an Example was measured with the following method.
(1) Molecular weight device: High-speed GPC device manufactured by Tosoh Corporation HLC-8120GPC
Column: Two TSK-GEL SUPER H2000 connected column manufactured by Tosoh Corporation Column temperature: 40 ° C
Detector: Differential refractometer Eluent: THF
Column flow rate: 0.6 ml / min
(2) Viscosity equipment: Shibaura System Co., Ltd. Bismetron VG-A

[Synthesis Example 1] Production of amino group- and hydroxyl group-containing (meth) acrylic polymer A1 A 4-liter flask having a capacity of 3 liters equipped with a thermometer, a stirrer, an inert gas inlet, an air inlet and a reflux condenser was charged with a solvent. 630 parts by mass of xylene was weighed and heated to 105 ° C. In this flask, 406.4 parts by mass of methyl methacrylate, 477.5 parts by mass of n-butyl methacrylate, 61.1 parts by mass of 2-hydroxyethyl methacrylate, 105.0 parts by mass of 2-dimethylaminoethyl methacrylate, 210.0 xylene. A mixture of 10.5 parts by mass of Kayaester-O (manufactured by Kayaku Akzo Co., Ltd.) as an initiator was added dropwise to carry out the reaction. The dropping reaction was carried out for 4 hours while maintaining at 110 ° C. with stirring. Further, a mixture of 210.0 parts by mass of xylene and 1.05 parts by mass of Kayaester-O was added dropwise over 1 hour to carry out the reaction. Furthermore, it heated at 110 degreeC for 3 hours, and obtained the 50 mass% solution of the (meth) acrylic polymer (A1) which has an amino group and a hydroxyl group in a side chain.
Solid content: 50% by mass
Amine value: 17.8 mg KOH / g
Hydroxyl value: 12.5mgKOH / g
Viscosity: 2620 mPa · s / 25 ° C
Molecular weight (Mn): 10800

[Synthesis Example 2] Production of amino group- and hydroxyl group-containing (meth) acrylic polymer A2 Into a three-liter four-flask equipped with a thermometer, stirrer, inert gas inlet, air inlet and reflux condenser, 630 parts by mass was weighed and heated to 105 ° C. In this flask, 452.8 parts by mass of methyl methacrylate, 532.1 parts by mass of n-butyl methacrylate, 29.3 parts by mass of 2-hydroxyethyl methacrylate, 35.4 parts by mass of 2-dimethylaminoethyl methacrylate, 210.0 parts of xylene. A mixture of 1 part by mass and 10.5 parts by mass of Kayaester-O was added dropwise to carry out the reaction. The dropping reaction was carried out for 4 hours while maintaining at 110 ° C. with stirring. Further, a mixture of 210.0 parts by mass of xylene and 1.05 parts by mass of Kayaester-O was added dropwise over 1 hour to carry out the reaction. Furthermore, it heated at 110 degreeC for 3 hours, and obtained the 50 mass% solution of (meth) acrylic polymer A2 which has an amino group and a hydroxyl group in a side chain.
Solid content: 50% by mass
Amine value: 6 mgKOH / g
Hydroxyl value: 6 mgKOH / g
Viscosity: 1950 mPa · s / 25 ° C
Molecular weight (Mn): 11800

[Synthesis Example 3] Production of (meth) acrylic polymer A3 630 parts by mass of xylene was weighed into a 4-liter flask having a capacity of 3 liters equipped with a thermometer, stirrer, inert gas inlet, air inlet and reflux condenser. And heated to 105 ° C. In this flask, a mixture of 433.7 parts by mass of methyl methacrylate, 616.3 parts by mass of n-butyl methacrylate, 210.0 parts by mass of xylene, and 10.5 parts by mass of Kayaester-O was reacted. . The dropping reaction was carried out for 4 hours while maintaining at 110 ° C. with stirring. Further, a mixture of 210.0 parts by mass of xylene and 1.05 parts by mass of Kayaester-O was added dropwise over 1 hour to carry out the reaction. Furthermore, it heated at 110 degreeC for 3 hours, and obtained the 50 mass% solution of acrylic polymer A3 which does not have functional groups, such as a hydroxyl group.
Solid content: 50% by mass
Viscosity: 1140 mPa · s / 25 ° C
Molecular weight (Mn): 9560

Synthesis Example 4 Production of Silane Coupling Agent 1 Takenate D-110N (Mitsui Chemicals) 400 parts by mass, 3-mercaptopropyltrimethoxysilane 16 parts by mass, and tetramethylammonium chloride 1 part by mass in a nitrogen atmosphere Then, the reaction was carried out at 60 ° C. for 6 hours to synthesize a silane compound having an isocyanate group at the molecular end.
Solid content: 76% by mass
NCO content: 10.2% by mass
SiO ₂ conversion: 1.17% by mass

<Preparation of UV curable coating composition>
[Example 1]
175.4 parts by mass of a 50% by mass solution of (meth) acrylic polymer A1 obtained in Synthesis Example 1, 24.1 parts by mass of silane coupling agent 1 obtained in Synthesis Example 4, and dipenta which is an ultraviolet curable compound 20.0 parts by mass of erythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 0.8 parts by mass of Irgacure 184 (manufactured by Ciba Specialty Chemicals) which is a photopolymerization initiator, and n-butyl acetate 33. 4 parts by mass were stirred and mixed to prepare an ultraviolet curable coating composition.

[Examples 2 to 8, Comparative Examples 1 to 7]
An ultraviolet curable coating composition was prepared in the same manner as in Example 1 except that the composition was changed to that shown in Table 1.

About the ultraviolet curable coating composition prepared in each of the above Examples and Comparative Examples, the adhesion, pencil hardness and flexibility to each substrate were measured and evaluated by the following methods. The results are shown in Table 2.
(1) Adhesiveness (1-1) Preparation of coating film Each substrate surface is cleaned with a solvent methyl ethyl ketone, diluted with a solvent n-butyl acetate so that the solid content of the paint becomes 30% by mass, and then with a 50 micron applicator. Applied. After coating, it was dried at 70 ° C. for 30 minutes, and further irradiated with ultraviolet rays to form a cured coating film of 10 microns. Irradiation was performed under the conditions of (80 mW / cm ² , 1200 mJ / cm ² ).
(1-2) Standard Adhesion Test After the coating film is cured and formed on each substrate by the above method, the surface of the coating film is 10 × 10 based on the cross-cut test of JIS K 5600-5-6 (2007 edition). A cell was prepared on the cell, cellophane tape (CT-24 manufactured by Nichiban Co., Ltd.) was applied, and the tensile peeling state was confirmed upward. The squares that were not peeled off were recorded, and the evaluation criteria were as follows.
○: Class 0 and Class 1 (there is almost no peeling)
Δ: Category 2 (peeling of the cross-cut portion is 5% or more and less than 15%)
X: State of classification 3, classification 4 and classification 5 (cross cut part is peeled 15% or more)
(1-3) Warm water adhesion test After the coating film was cured and formed on each substrate by the above method, it was immersed in boiling water at 100 ° C. for 60 minutes, wiped with a dry cloth, and dried for 24 hours. Based on the cross-cut test of JIS K 5600-5-6 (2007 version), 10 × 10 squares are made on the coating surface, cellophane tape (CT-24 manufactured by Nichiban Co., Ltd.) is pasted, and pulled upward. The peeling situation was confirmed. The squares that were not peeled off were recorded, and the evaluation criteria were as follows.
○: Class 0 and Class 1 (there is almost no peeling)
Δ: Category 2 (peeling of the cross-cut portion is 5% or more and less than 15%)
X: State of classification 3, classification 4 and classification 5 (cross cut part is peeled 15% or more)
(2) Pencil hardness About the coating film produced on each base material with the said method, it measured based on prescription | regulation of JISK5600-5-4 (2007 edition). As a measuring device, “Pencil Scratch Hardness Tester” manufactured by Sanko Electronic Laboratory Co., Ltd. was used. As an evaluation standard, the hardness of the hardest pencil that did not cause a scar was used as a hardness display in accordance with JIS K 5600-5-4.
(3) Flexibility Using a mandrel with a diameter of 12 mm used for the evaluation of JIS K 5600-5-1 bending resistance, the coated plate was folded 90 ° with the painted surface facing, and the bent portion was observed and evaluated. .
○: No change in appearance △: Small cracks are observed ×: Peeling and cracking of the coating film are observed

As shown in Table 2, it can be seen that the coating formed from the ultraviolet curable coating composition prepared in each example is excellent in adhesiveness to various substrates.
In addition, when the silane coupling agent 1 having an isocyanate group is used, the flexibility is excellent even when the blending amount of the ultraviolet curable compound is increased as compared with the case of using the silane coupling agent 2 having an epoxy group. It can be seen that a film is obtained.

Claims (9)

(A) an acrylic resin having a first functional group selected from an amino group, a hydroxyl group, a carboxyl group, an epoxy group, and an isocyanate group; and (B) a second functional group having reactivity with the first functional group. An alkoxysilane compound having (C) an ultraviolet curable compound, and (D) a photopolymerization initiator,
The ultraviolet curable coating composition, wherein (C) the ultraviolet curable compound is contained in a total solid content of 10 to 80% by mass.   The ultraviolet curable coating composition according to claim 1, wherein the acrylic resin (A) has an amino group and / or a hydroxyl group.   The ultraviolet curable coating composition according to claim 2, wherein the acrylic resin (A) has both an amino group and a hydroxyl group.   The ultraviolet curable coating composition according to claim 2 or 3, wherein the amino group is a tertiary amino group.   The ultraviolet curable coating composition according to any one of claims 2 to 4, wherein the (A) acrylic resin has a total of 10 mgKOH / g or more of the amino group and / or hydroxyl group.   The ultraviolet curable coating composition according to any one of claims 2 to 4, wherein the (B) alkoxysilane compound has an epoxy group and / or an isocyanate group. The ultraviolet curable coating composition according to claim 1, wherein the silicon atom concentration is 0.05% by mass or more in the total solid content in terms of SiO ₂ . A substrate and a coating formed directly on the surface of the substrate;
A coated product, wherein the coating is formed from the composition according to any one of claims 1 to 7.   The coated product according to claim 8, wherein the substrate is made of a metal or a metal oxide.