JPH11106468A - Photo-setting resin composition and coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photo-setting resin composition, capable of being diluted with water or an alcohol-based solvent, good in water resistance of a coating film and containing a urethane acrylate. SOLUTION: This composition consists essentially of (A) a urethane acrylate compound in which the hydroxyl group of a hydroxyl group-containing urethane compound is blocked by carrying out a urethane-forming reaction of (a) the hydroxyl group-containing urethane compound prepared by reacting (a) an isocyanate component having two isocyanato groups in one molecule with (b) a diol compound having at least one carboxyl group in one molecule, (c) a triol compound, (d) a terminal hydroxyl group-containing glycol compound and (e) a hydroxyl group-containing unsaturated compound with a one terminal isocyanato group-containing acrylate compound and both terminals have unsaturated groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photocurable resin composition containing urethane acrylate and a paint.

[0002]

2. Description of the Related Art It is known that a photocurable resin composition containing urethane acrylate and that this photocurable resin composition is used as a coating material (JP-A-50-66596, JP-A-50-94090). Reference). These days,
Use of a photocurable resin composition as a coating material for the purpose of improving productivity has been increasing. In recent years, volatile organic compounds (VOC: Volatile Organic) have been used from the viewpoints of pollution prevention, environmental protection, and work environment improvement.
Due to the regulation of Compound, there is a tendency to reduce the content of organic solvents in coatings, and from such a viewpoint, photocurable resin compositions that can be made solvent-free or high-solid are growing significantly in the coatings market. .

[0003]

SUMMARY OF THE INVENTION Under such circumstances,
In the field of woodwork, paper, plastic, and metal coating, because of its flexibility, water-based photocurable resin compositions containing urethane acrylate are being studied, but the water resistance of the cured coating film is poor. Improvements were awaited.

In general, a solvent-free photocurable resin composition used as a paint is used to form a paint film having a good appearance and to improve the storage stability of the paint. And a photopolymerizable monomer such as an acrylic monomer. This photopolymerizable monomer also functions as a coating film forming component. However, many of the photopolymerizable monomers are highly irritating to the skin and easily cause rash, chemical injury, and the like during handling by an operator, and it has been desired that the amount of the photopolymerizable monomer can be reduced.

An object of the present invention is to provide a urethane acrylate-containing photocurable resin composition which can be diluted with water or an alcoholic solvent and has good water resistance of a coating film. Make it an issue. Another object of the present invention is to provide a photocurable resin composition containing urethane acrylate, which has good handling properties and contains urethane acrylate. Furthermore, an object of the invention according to claim 3 is to provide a photocurable resin composition having good water dispersibility, in addition to the above-mentioned problems. Furthermore, the inventions according to claims 4 to 5 have, in addition to the above objects, a urethane acrylate which can form a coating film having a good coating appearance and has good storage stability when used as a coating material. It is an object to provide a photocurable resin composition containing the same. A further object of the present invention is to provide a paint containing the photocurable resin composition containing the urethane acrylate.

[0006]

The invention according to claim 1 is an isocyanate compound (a) component having two isocyanate groups in one molecule, a diol compound having at least one carboxyl group in one molecule ( b) a triol compound (c) component, a hydroxyl group-containing glycol compound (d) component, and a hydroxyl group-containing urethane compound obtained by reacting a hydroxyl group-containing unsaturated compound (e) component with one end isocyanate group-containing The present invention relates to a photocurable resin composition comprising, as an essential component, a urethane acrylate compound (A) in which a hydroxyl group of a hydroxyl group-containing urethane compound is blocked by a urethanization reaction with an acrylate compound and has an unsaturated group at both terminals.

As the isocyanate compound (a) component having two isocyanate groups in one molecule used in the synthesis of the urethane acrylate compound (A), the viscosity of the urethane acrylate compound (A) is reduced and the thixotropy is reduced. Isophorone diisocyanate, tolylene diisocyanate, xylene diisocyanate, and trimethylhexamethylene diisocyanate are preferred because they impart good handling properties. That is, claim 2
The invention described in (1), wherein the isocyanate compound (a) component in the urethane acrylate compound (A) component is one or more kinds selected from isophorone diisocyanate, tolylene diisocyanate, xylene diisocyanate, and trimethylhexamethylene diisocyanate. The present invention relates to a curable resin composition.

The urethane acrylate compound (A)
Since the carboxyl group has good water dispersibility,
It is preferably neutralized with an amino group having no active hydrogen. That is, the invention according to claim 3 relates to a photocurable resin composition in which a carboxyl group of the urethane acrylate compound (A) is neutralized by an amino group having no active hydrogen.

Further, in order to improve the storage stability of the paint and to adjust the viscosity to improve the appearance of the coating film, in addition to the urethane acrylate compound (A), a photocurable unsaturated double It is preferable to use a water-soluble photopolymerizable monomer (B) having one or more bonds in one molecule. That is, the invention according to claim 4 has, in addition to the urethane acrylate compound (A) in which the hydroxyl group of the hydroxyl group-containing urethane compound has been blocked, one or more photocurable unsaturated double bonds per molecule. Water-soluble photopolymerizable monomer (B)
And a photo-curable resin composition comprising as an essential component.

One photocurable unsaturated double bond per molecule
As the water-soluble photopolymerizable monomer (B) having at least one monomer, acryloyl morpholine,
It is preferable to use N-vinylpyrrolidone or N-vinylcaprolactam alone or in combination. That is, in the invention according to claim 5, the water-soluble photopolymerizable monomer (B) is one or more selected from acryloylmorpholine, N-vinyl-2-pyrrolidone, and N-vinylcaprolactam. Item 4 relates to the photocurable resin composition according to item 4.

The above-described photocurable resin composition is formed into a paint by blending a pigment and other necessary components as a coating film forming component. That is, the invention described in claim 6 is based on claim 1
And a coating containing the photocurable resin composition according to any one of (1) to (5).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION One molecule has two isocyanate groups.
Examples of the isocyanate compound (a) component having the following are the above-mentioned isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethyl xylylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, trimethyl Hexamethylene diisocyanate, tetramethyl xylylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like can be used. They are,
They may be used alone or in combination of two or more.

As the diol compound (b) having at least one carboxyl group in one molecule, dimethylolpropionic acid, dimethylolbutanoic acid, trimethylolpropane, glycerin or the like and ε-caprolactone are added and polymerized. Functional polyols and cyclic acid anhydrides such as maleic anhydride, phthalic anhydride, succinic anhydride, etc. have at least one or more carboxyl groups and two hydroxyl groups in one molecule obtained by ring-opening addition reaction. Half ester compounds and the like can be used. These may be used alone or in combination of two or more.

As the triol compound (c), for example, ring-opening polymerization of trimethylolpropane, triethylolpropane, glycerin, trimethylolpropane and ε-caprolactone together with a catalyst such as an organic titanium type, an organic tin type or perchloric acid. The ε-caprolactone-modified triol obtained in the above can be used. These may be used alone or in combination of two or more. The number average molecular weight of the triol compound (c) component is preferably 2000 or less. When the number average molecular weight exceeds 2,000, the water dilutability and storage stability of the urethane acrylate compound (A) are deteriorated, and sufficient coating film strength tends not to be obtained.

The terminal hydroxyl group-containing glycol compound (d) can be obtained by, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene oxide-modified bisphenol, propylene oxide-modified bisphenol, or copolymerization of ethylene oxide and propylene oxide. Polyglycols, copolymerized polyols in which the structural unit represented by formula (1) and the structural unit represented by formula (2) are randomly bonded, and the like can be used. These may be used alone or in combination of two or more.

Embedded image The number average molecular weight of the terminal hydroxyl group-containing glycol compound (d) is preferably in the range of 300 to 3000. If the number average molecular weight is less than 300, sufficient elongation cannot be obtained when a coating film is formed, and if it exceeds 3000, sufficient coating film strength tends not to be obtained.

Examples of the hydroxyl group-containing unsaturated compound (e) include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, pentaerythritol triacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate.
A hydroxyalkyl acrylate or hydroxyalkyl methacrylate such as hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, pentaerythritol trimethacrylate can be used.
These may be used alone or in combination of two or more.

Isocyanate compound (a) component, diol compound (b) component having at least one carboxyl group in one molecule, triol compound (c) component, glycol compound having terminal hydroxyl group (d) component, and hydroxyl group The compounding ratio of the unsaturated compound (e) is as follows: the isocyanate group of the component (a) and the total amount of the hydroxyl groups of the components (b), (c), (d) and (e). It is preferable that the isocyanate group / hydroxyl group = 1/1 to 1 / 1.2. Further, the component (c) and the sum of the components (b), (d) and (e) are represented by an equivalent ratio of a hydroxyl group,
The total of component (c) / component (b), component (d), and component (e) is preferably 10/90 to 65/35, and more preferably 15/85 to 40/60.
The components (b), (d) and (e) are blended in such a manner that each hydroxyl group accounts for 10 to 85 mol% with respect to the total amount of these hydroxyl groups. Is preferred. The synthesis method is not particularly limited. For example, the components (b), (c), (d) and (e), the polymerization inhibitor and the urethanizing catalyst are charged into a flask, and preferably 40
A method in which the mixture is heated to about 70 ° C. and the component (a) is added dropwise can be used. The completion of the reaction was determined to be 2270 by IR measurement.
This can be achieved by maintaining the heat retention until there is no trace of the NCO characteristic absorption band at cm ⁻¹ . As the urethanization catalyst, known urethanization catalysts such as tin-based and amine-based can be used.

The acrylate having an isocyanate group at one terminal includes a hydroxyl group-containing acrylate having at least one acryloyl or methacryloyl group and one hydroxyl group in a molecule, and a diisocyanate having two isocyanate groups in one molecule. And the compound, preferably, hydroxyl group equivalent / isocyanate equivalent = 0.5
/ 1 to 0.82 / 1, obtained by a urethanization reaction,
Isocyanate terminated acrylate compounds can be used. Examples of the hydroxyl group-containing acrylate or methacrylate include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
And hydroxyalkyl acrylates such as -hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, pentaerythritol triacrylate, and pentaerythritol trimethacrylate. Above all, pentaerythritol triacrylate is preferred because it gives good water resistance to the obtained coating film. Examples of the diisocyanate compound having two isocyanate groups in one molecule include, for example, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate,
Hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethyl xylylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate. Above all, since the viscosity of the obtained one-terminal isocyanate group-containing acrylate compound is low, trimethylhexamethylene diisocyanate, tetramethyl xylylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate The single diisocyanate compound selected is preferred. (A) component, (b) component,
The hydroxyl group-containing urethane compound, which is a reaction product of the component (c), the component (d), and the component (e), and the one-terminal isocyanate group-containing acrylate obtained above are the same as the former hydroxyl group and the latter isocyanate. It is preferable to mix and react such that the equivalent ratio with the group becomes former / latter = 1/1 to 1 / 0.8. This reaction, for example,
A method in which a hydroxyl group-containing urethane compound and a urethanization catalyst are charged into a flask, heated to 40 to 70 ° C., and one-terminal isocyanate-containing acrylate is dropped. As the urethanization catalyst, known urethanization catalysts such as tin-based and amine-based can be used.

The urethane acrylate compound (A) has a number average molecular weight of 1,000 to 1,000 from the viewpoint of storage stability when diluted with water and strength of the coating film when cured.
It is preferably 0, more preferably 1000 to 5000.

As the water-soluble photopolymerizable monomer (B), a monofunctional or polyfunctional acrylate compound or the like can be preferably used. Such compounds include:
2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, methoxydiethylene glycol acrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol acrylate, ethoxydiethylene glycol methacrylate, N, N-dimethylaminoethyl acrylate, N , N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl acrylate,
N-diethylaminoethyl methacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, ethylene oxide-added trimethylolpropane triacrylate, ethylene oxide-added trimethylol Propane trimethacrylate, N
-Vinylpyrrolidone, acryloylmorpholine, N-
And vinyl caprolactam. These may be used alone or in combination of two or more. The water-soluble photopolymerizable monomer (B) is preferably blended in an amount of 0 to 50 parts by mass, particularly preferably 25 parts by mass, based on the total amount of the urethane acrylate compound (A). When this amount exceeds 50 parts by mass, properties such as surface curability, elongation, strength, and adhesion of the resulting coating film tend to be generally reduced.

The photocurable resin composition of the present invention is usually used by blending a photopolymerization initiator. As the photopolymerization initiator, for example, a carbonyl-based photopolymerization initiator, for example,
Benzophenone, diacetyl, benzyl, benzoin,
ω-bromoacetophenone, chloroacetone, acetophenone, 2,2-diethoxyacetophenone, 2,2-
Dimethoxy-2-phenylacetone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, p, p'-bisdiethylaminobenzophenone, Michler's ketone, benzoin methyl ether, benzoin isobutyl ether, benzoin-n-butyl ether Benzylbenzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2
-Hydroxy-2-methyl-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, methylbenzoylformate, 2,2
-Diethoxyacetophenone, 4-N, N'-dimethylacetophenone and the like, sulfide-based photopolymerization initiators such as diphenyldisulfide and dibenzyldisulfide, and quinone-based photopolymerization initiators such as benzoquinone and anthraquinone; Azo-based photopolymerization initiators, for example, azobisisobutyronitrile, 2,2′-azobispropane, hydrazine, etc., sulfochloride-based photopolymerization initiators, for example, thioxanthone, etc., peroxide-based photopolymerization Initiators include, for example, benzoyl peroxide, di-t-butyl peroxide and the like, and isoamyl o-dimethylaminobenzoate and the like. Of these, 2-hydroxy-
2-Methyl-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, and the like are preferable in terms of solubility. These may be used alone or in combination of two or more. The photopolymerization initiator comprises a urethane acrylate compound (A) and a water-soluble photopolymerizable monomer (B)
Is preferably used in an amount of 1 to 10 parts by mass, particularly 3 to 5 parts by mass, based on 100 parts by mass in total. When the amount is less than 1 part by mass, the photocurability is not sufficient, and when it exceeds 10 parts by mass, the physical properties of the obtained coating film tend to be generally deteriorated.

When the photocurable resin composition of the present invention is used as a paint, it is put to practical use by blending a polymerization inhibitor, a leveling agent, a filler or a pigment, and other modifiers as necessary. Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, benzoquinone, pt-butylcatechol, 2,6-di-t-butyl-4-methylphenol and the like. Examples of the leveling agent include polyether-modified dimethylpolysiloxane copolymer, polyester-modified dimethylpolysiloxane copolymer, polyether-modified methylalkylpolysiloxane copolymer, aralkyl-modified methylalkylpolysiloxane copolymer, and polyether-modified And methylalkylpolysiloxane copolymers. As fillers or pigments, calcium carbonate, talc, mica,
Examples include clay, silica powder, colloidal silica, barium sulfate, aluminum hydroxide, zinc stearate, zinc white, red iron oxide, azo pigment and the like. Other modifiers include unsaturated polyester resins, vinyl ester resins, vinyl urethane resins, vinyl ester urethane resins, polyisocyanates, polyepoxides, epoxy-terminated polyoxazolidones, acrylic resins, alkyd resins, urea resins, melamine resins And polydiene elastomers, saturated polyesters, saturated polyethers, nitrocellulose, cellulose derivatives such as cellulose acetate butyrate, and oils and fats such as linseed oil, tung oil, soybean oil, castor oil, epoxidized oil, etc. Polymeric substances.

Further, a photopolymerizable monomer other than the water-soluble photopolymerizable monomers described below and an organic solvent can also be blended. Examples of the photopolymerizable monomer other than the water-soluble photopolymerizable monomer include, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, ethylhexyl acrylate, and isodecyl. Acrylate, n-hexyl acrylate, stearyl acrylate, lauryl acrylate, tridecyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, glycidyl acrylate, 2-hydroxyethyl acrylate, 2-
Methoxyethoxy acrylate, 2-ethoxyethoxyethyl acrylate, methoxydipropylene glycol acrylate, octafluoropentyl acrylate,
Allyl acrylate, 1,3-butanediol acrylate, 1,4-butanediol acrylate, 1,6-
Hexanediol acrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, tripropylene glycol diacrylate, hydroxypivalic acid ester neopentyl glycol diacrylate, trimethylolpropane diacrylate, 1,3-bis (hydroxyethyl) -5 5-dimethylhydantoin, 3-methylpentanediol acrylate, α, ω-diacrylbisdiethylene glycol phthalate, trimethylolpropane triacrylate, pentaerythritol acrylate, pentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, α, ω-tetraallylbistrimethylolpropane tetrahydrophthalate, 2
-Hydroxyethyl acryloyl phosphate, trimethylolpropane trimethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol Dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate,
Diacryloxyethyl phosphate and the like.
Examples of the organic solvent include a hydrocarbon organic solvent, an ester organic solvent, and a ketone organic solvent.

The photocurable resin composition of the present invention may be made of a metal material such as iron and aluminum, a calcium silicate plate, a lightweight concrete plate, an asbestos cement plate, an inorganic building material such as mortar, etc.
It can be used as an ultraviolet-curable paint for wood, paper, plastic substrates, etc., and as a printing ink.

[0025]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In the following, unless otherwise specified,
Parts are parts by weight and% is percent by weight.

Example 1 After introducing air gas into a reaction vessel equipped with a stirrer, thermometer, cooling pipe and air gas introduction pipe, 232 parts (2 moles) of 2-hydroxyethyl acrylate and a number average molecular weight of about 68 were obtained.
682 parts (1 mol) of polyoxytetramethylene glycol (manufactured by Hodogaya Chemical Industry Co., Ltd., PTG650SN (trade name)) and 50.6 parts of glycerin (0.
55 mol), hydroquinone monomethyl ether 0.8
Parts, dibutyltin dilaurate 1.6 parts, hydroxyl value 216.1 mgKOH / g, acid value 107.7 mgKO
H / g carboxyl group-containing polycaprolactone diol (PLACCEL20, manufactured by Daicel Chemical Industries, Ltd.)
5A (trade name) 260 parts (0.5 mol) were charged, the temperature was raised to 70 ° C., and the temperature was kept at 70 to 75 ° C., and 666 parts (3 mol) of isophorone diisocyanate was uniformly dropped in 3 hours. Reacted. After the completion of the dropwise addition, the reaction was continued for about 15 hours. After confirming that the isocyanate had disappeared by IR measurement, the reaction was terminated, and the number average molecular weight was 2500 and the acid value was 1
5 mg KOH / g, hydroxyl value 14.5 mg KOH
/ G of a hydroxyl group-containing urethane compound (a-1).

After introducing air gas into a reaction vessel equipped with a stirrer, a thermometer, a cooling pipe and an air gas introduction pipe, 222 parts of isophorone diisocyanate were charged, and the temperature was raised to 70 ° C. and then kept at 70 to 75 ° C. , 2-hydroxyethyl acrylate, 116 parts of hydroquinone monomethyl ether, 0.17 parts of dibutyltin dilaurate, 0.05 part of dibutyltin dilaurate was dropped uniformly over 2 hours and reacted. After completion of the dropwise addition, the reaction was continued for about 4 hours, and the amount of isocyanate was 12.0%.
The acrylate compound (a′-1) having one end isocyanate group was obtained.

After introducing an air gas into a reaction vessel equipped with a stirrer, a thermometer, a cooling pipe and an air gas introduction pipe, 500 parts of the urethane acrylate compound (a-1) obtained above was added.
After raising the temperature to 70 ° C., the temperature was kept at 70 to 75 ° C., and the isocyanate amount obtained above was 12.0%, and the isocyanate group-containing acrylate compound having one terminal isocyanate (a′-1) 4
4.5 parts were uniformly dropped over 3 hours to cause a reaction. The reaction was continued for about 6 hours after the completion of the dropwise addition, and the disappearance of the isocyanate was confirmed by IR measurement. The reaction was terminated to obtain a urethane acrylate compound having a number average molecular weight of 3000 and an acid value of 13.5 mgKOH / g. Next, a mixture of 817 parts of distilled water and 13.8 parts of triethylamine was uniformly dropped for 2 hours to obtain a urethane acrylate compound (A-1) in which a carboxyl group was neutralized with an amino group.

The obtained urethane acrylate compound (A
-1) 100 parts, ACMO as a water-soluble photopolymerizable monomer
10 parts, 2 parts by weight of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator based on the urethane acrylate compound (A-1), and a leveling agent (BYK Chemie (Germany)) 301 (trade name)) and urethane acrylate compound (A
-1) was added in an amount of 0.5 part by mass and uniformly mixed to obtain a photocurable resin composition.

Example 2 In Example 1, 260 parts of carboxyl group-containing polycaprolactone diol was changed to 75 parts of dimethylolbutanoic acid, the number average molecular weight was 2,000, and the acid value was 15 mg KO.
A hydroxyl group-containing urethane compound (a-2) having H / g and a hydroxyl value of 16.3 mgKOH / g was obtained. Next, in the synthesis of the acrylate compound containing one terminal isocyanate group in Example 1, 116 parts of 2-hydroxyethyl acrylate was changed to 460 parts of pentaerythritol triacrylate (hydroxyl value, 122 mg KOH / g), and the amount of isocyanate was 6. 0% of an acrylate compound containing one end isocyanate group (a′-2) was obtained. Next, a hydroxyl group-containing urethane compound (a-
2) 102.5 parts of an isocyanate group-containing acrylate compound having one end isocyanate group (a'-2) having an isocyanate amount of 6.0% obtained above was uniformly added dropwise to 500 parts over 3 hours. The reaction was carried out in the same manner as in Example 1 to obtain a urethane acrylate compound having a number average molecular weight of 2500 and an acid value of 12.0 mgKOH / g. Next, distilled water 135
A mixture of 7 parts and 13.6 parts of triethylamine was uniformly dropped for 2 hours to obtain a urethane acrylate compound (A-2) having a carboxyl group neutralized with an amino group, and photocured in the same manner as in Example 1. A resin composition was obtained.

Example 3 In Example 1, 232 parts of 2-hydroxyethyl acrylate was changed to 920 parts of pentaerythritol triacrylate (hydroxyl number, 122 mg KOH / g), and the number average molecular weight was 3000 and the acid value was 14.7 mg KO.
A hydroxyl group-containing urethane compound (A-3) having H / g and a hydroxyl value of 12 mgKOH / g was obtained. Thereafter, a photocurable resin composition was obtained in the same manner as in Example 1.

Comparative Example 1 After introducing air gas into a reaction vessel equipped with a stirrer, a thermometer, a cooling pipe and an air gas introducing pipe, the hydroxyl group-containing urethane compound (a-1) obtained in Example 1 was subjected to 500
The mixture was heated to 70 ° C. and then kept at 70 to 75 ° C., and a mixture of 750 parts of distilled water and 13.1 parts of triethylamine was uniformly dropped for 2 hours, and a urethane acrylate in which a carboxyl group was neutralized with an amino group. Compound (A-4) was obtained, and a photocurable resin composition was obtained in the same manner as in Example 1 below.

Example 4 A photocurable resin composition was obtained in the same manner as in Example 1 except that no water-soluble photopolymerizable monomer was added.

The storage stability of the photocurable resin composition obtained above was examined by visually observing the state after storage at room temperature for one month.

The bar coater No. 20, the obtained photocurable resin composition was applied to a transparent hard vinyl chloride plate (150 mm × 70 mm × 2 mm), dried in a hot air dryer heated to 60 ° C. for about 10 minutes, and then exposed to ultraviolet light. Irradiation equipment (6kw, 80w / cm high pressure mercury lamp x 2)
With a single high-pressure mercury lamp, the irradiation distance is 15 cm and the conveyor speed is 10 m / min.
² ) Regarding the coating film formed by irradiating ultraviolet rays under the conditions of
The coating film appearance, water resistance, surface curability, and adhesion were examined as follows. Coating appearance: The smoothness of the coating surface was visually evaluated. Water resistance: 1 ml of distilled water was dripped on the surface of the coating film, covered with a watch glass, allowed to stand for 24 hours, and the appearance of the coating film surface was visually observed. Surface curability: The tackiness of the surface was evaluated by touching the coating film surface. Adhesion: Checked according to JIS-K-5400 cross-cut peel test.

Using a 150 μm applicator, the obtained photocurable resin composition was applied on a glass plate, dried in a hot air dryer heated to 60 ° C. for about 10 minutes, and then irradiated with an ultraviolet irradiation device (6 kW, 80w / cm high pressure mercury lamp x 2)
A coating film formed by irradiating an ultraviolet ray with one high-pressure mercury lamp at an irradiation distance of 15 cm and a conveyor speed of 10 m / min (a single irradiation amount of about 250 mJ / cm ² ) is peeled off to form a cured film having a thickness of about 100 μm. Was prepared, and the elongation and tensile strength were examined as follows.

Elongation: A test piece prepared by cutting the prepared cured film into a rectangular shape having a length of 100 mm and a width of 10 mm at an environmental temperature of 5 ° C. was placed at 25 ° C. in a one-way / two-way refrigerator type thermostat. At ambient temperature, the cured film was pulled at a test span of 50 mm at a pulling rate of 10 mm / min until the cured film was broken, and was obtained from the elongation at break (mm) according to Equation (1).

Elongation (%) = 100 × (Elongation at break / 50) (1)

Tensile strength: In the elongation test, the tensile strength was determined from the breaking strength (N) according to the following equation (2).

## EQU2 ## Tensile strength = breaking strength / A · B (2) where A: width of test piece (cm), B: thickness of test piece (cm) Table 1 shows the test results. In Table 1, in the item of the coating film appearance, は indicates that the coating film is uneven, X indicates that the coating film is uneven, and in the item of water resistance, は indicates that there is no abnormality,
× indicates blister generation, and in the item of surface curability,
The absence indicates that there is no tack, and the presence indicates that there is a slight tack.

[0039]

Table 1 Example 1 Example 2 Example 3 Comparative Example 1 Example 4 ─────────────────────────────────── Storage stability good good good good good with sediment Film appearance ○ ○ ○ ○ × Water resistance ○ ○ ○ × ○ Surface curability None None None Yes None Adhesion 100/100 100/100 100/100 100/100 100/100 Elongation (%) 130 50 140 140 140 100 Tensile strength (MPa) 18.62 39.2 19.6 29.4 39.2 ───────────────────────────────────

[0040]

According to the present invention, the photocurable resin composition containing urethane acrylate can be diluted with water or an alcohol solvent, and the coating film can have good water resistance.

Claims (6)

[Claims] 1. An isocyanate compound (a) component having two isocyanate groups in one molecule, a diol compound (b) component having at least one carboxyl group in a molecule, a triol compound (c) component, and a terminal hydroxyl A hydroxyl group-containing urethane compound by a urethanization reaction of a hydroxyl group-containing urethane compound obtained by reacting a hydroxyl group-containing unsaturated compound (e) component with a hydroxyl group-containing unsaturated compound (e) component and an isocyanate group-containing acrylate compound at one end. A photocurable resin composition comprising, as an essential component, a urethane acrylate compound (A) having a hydroxyl group blocked and having unsaturated groups at both ends. 2. The isocyanate compound (a) component in the urethane acrylate compound (A) component is one or more selected from isophorone diisocyanate, tolylene diisocyanate, xylene diisocyanate, and trimethylhexamethylene diisocyanate. 2. The photocurable resin composition according to 1. 3. The photocurable resin composition according to claim 1, wherein the carboxyl group of the urethane acrylate compound (A) is a urethane acrylate compound neutralized with an amino group having no active hydrogen. 4. A water-soluble photopolymerizable monomer having at least one photocurable unsaturated double bond per molecule, in addition to the urethane acrylate compound (A) in which the hydroxyl group of the hydroxyl group-containing urethane compound is blocked. The photocurable resin composition according to claim 1, which comprises a monomer (B) as an essential component. 5. The light according to claim 4, wherein the water-soluble photopolymerizable monomer (B) is one or more selected from acryloylmorpholine, N-vinyl-2-pyrrolidone, and N-vinylcaprolactam. Curable resin composition. 6. A paint containing the photocurable resin composition according to claim 1.