JP7665184B2 - Method for producing active energy ray-curable water-soluble resin composition containing photochromic dye, coating composition, and cured article - Google Patents

Description

The present invention relates to a method for producing an active energy ray-curable water-soluble resin composition containing a photochromic dye, a coating composition, and a cured article.

Photochromic materials, for example, undergo reversible isomerization between two states with different absorption spectra upon irradiation with light, resulting in a change in color. Therefore, in recent years, such materials are expected to be used in various applications, such as light control, optical storage, and holograms. On the other hand, photochromic materials are oil-soluble (water-insoluble) due to their color-developing structure, and therefore it is difficult to use them as an aqueous solution or emulsion.
In response to this, proposals have been made in which a monomer that imparts photochromic properties is copolymerized with a monomer that imparts water solubility (e.g., Patent Document 1), in which a dichroic dye is made to exhibit a liquid crystal state using water as a solvent (e.g., Patent Document 2), and in which a photochromic material is emulsified using a surfactant (e.g., Patent Document 3).

Japanese Unexamined Patent Publication No. 63-308014 Special table 2018-3996 publication JP 2019-3103 A

However, depending on the application, there is a demand for the development of materials that can be used not only as an aqueous solution or emulsion but also have various other functions, such as durability (water resistance, solvent resistance), hard coat properties, etc.
An object of the present disclosure is to provide an active energy ray-curable water-soluble resin composition which not only contains a photochromic dye but also exhibits multiple functions and can be used as an aqueous solution or emulsion, and a method for producing the same, and a cured article obtained by curing the same.

This application includes the following inventions:
(1) reacting 1 mole of an isocyanate compound having (m+n) isocyanate groups with n moles of a hydroxyl group-containing (meth)acrylate compound;
Next, the resulting reaction product is reacted with an alkylene oxide (meth)acrylate adduct or a polyalkylene glycol compound having a hydroxyl group at one end in an amount of m moles,
Obtaining a urethane (meth)acrylate oligomer represented by formula (1),
adding water to the urethane (meth)acrylate oligomer while gently stirring or emulsifying the interface between the urethane (meth)acrylate oligomer and water to prepare a water-soluble urethane (meth)acrylate oligomer composition;
preparing a photochromic dye solution by dissolving a photochromic dye in an ethylenically unsaturated monomer;
The method for producing an active energy ray-curable water-soluble resin composition containing a photochromic dye is characterized by dissolving the photochromic dye solution in the water-soluble urethane (meth)acrylate oligomer composition.
(R ¹ O-CONH) _m -R ² -(NHCO-OR ³ )n (1)
(Wherein,
R ¹ O-- represents a dehydrogenation residue of a polyalkylene glycol compound having a hydroxyl group at one end or a (meth)acrylic acid alkylene oxide adduct;
^R2 is a residue of a deisocyanated group of an isocyanate compound,
^-OR3 is a dehydrogenated residue of a hydroxyl group-containing (meth)acrylate compound,
m and n each represent an integer between 1 and 50, provided that m≦n.
(2) The above-described production method, wherein the ethylenically unsaturated monomer is water-soluble.
(3) The above-described method, wherein the ethylenically unsaturated monomer has a glass transition temperature of 100° C. or higher as a homopolymer.
(4) The method for producing the above-described photochromic dye, wherein the photochromic dye is at least one selected from the group consisting of spirobenzopyran derivatives and diarylethene derivatives.
(5) The above-described production method, wherein the isocyanate compound is a diisocyanate or a polyisocyanate of a diisocyanate monomer.
(6) The method for producing the above-described polyalkylene glycol compound having a hydroxyl group at one end thereof is an alkoxy polyalkylene glycol.
(7) The method for producing the (meth)acrylic acid alkylene oxide adduct described above, wherein the (meth)acrylic acid alkylene oxide adduct is an alkylene oxide adduct of (meth)acrylic acid or a mono(meth)acrylate of polyalkylene glycol.
(8) The method for producing a hydroxyl group-containing (meth)acrylate compound according to the above, wherein the hydroxyl group-containing (meth)acrylate compound is a hydroxyalkyl (meth)acrylate, a polyol (meth)acrylate or an alkylene oxide-added polyol (meth)acrylate.
(9) The method for producing the above-described ethylenically unsaturated monomer is a (meth)acrylic acid compound or a vinyl group-containing compound.
(10) The method according to the above, wherein the (meth)acrylic acid compound is at least one selected from acrylic acid amides, alkyl (meth)acrylates, aminoalkyl (meth)acrylates, quaternary salts of aminoalkyl (meth)acrylates, alkoxy polyalkylene glycol (meth)acrylates, hydroxyalkyl (meth)acrylates, acid anhydride adducts of hydroxyalkyl (meth)acrylates, polyalkylene glycol di(meth)acrylates, alkyldiol di(meth)acrylates, polyol poly(meth)acrylates, and alkylene oxide-added polyol poly(meth)acrylates; and the vinyl group-containing compound is at least one selected from vinyl acetate, N-vinyl acetamide, vinyl pyrrolidone, vinyl alkyl ethers, vinyl sulfonic acid, and salts of vinyl sulfonic acid.
(11) The method for producing the above-described composition, wherein the solids ratio (weight ratio) of the water-soluble urethane (meth)acrylate oligomer composition, the ethylenically unsaturated monomer and the photochromic dye is 100:5-300:0.005-0.2.
(12) A coating composition comprising an active energy ray-curable water-soluble resin composition containing a photochromic dye obtained by the above-described production method.
(13) The coating composition described above, further comprising at least one photopolymerization initiator.
(14) The coating composition according to the above, wherein the photopolymerization initiator is contained in an amount of 0.002 to 10 parts by weight per 100 parts by weight of the total solid content of the water-soluble urethane (meth)acrylate oligomer composition and the ethylenically unsaturated monomer.
(15) A cured article comprising a substrate and a film of the coating composition described above formed on the surface of the substrate.

The present invention provides an active energy ray-curable water-soluble resin composition that not only contains a photochromic dye but also exhibits multiple functions and can be used as an aqueous solution or emulsion, a method for producing the same, and a cured article obtained by curing the same.

In this specification, "(meth)acrylate", "(meth)acrylic acid", etc. respectively mean "at least one selected from the group consisting of acrylate and methacrylate", "at least one selected from the group consisting of acrylic acid and methacrylic acid", etc. Furthermore, the numerical ranges expressed by "to" include the numerical values before and after it. In this specification, "solid content" means "heating residue" in the examples, and usually coincides with "concentration of curing component". Furthermore, in this specification, "parts" means "parts by weight". Furthermore, molecular weight means weight average molecular weight, and indicates the value measured by the method described in paragraph 15.

[Method for producing a photochromic dye-containing active energy ray-curable water-soluble resin composition]
In the present invention, a method for producing an active energy ray-curable water-soluble resin composition containing a photochromic dye (hereinafter, sometimes simply referred to as a "dye-containing composition") includes the steps of:
(a) providing a water-soluble urethane (meth)acrylate oligomer composition;
(b) dissolving a photochromic dye in an ethylenically unsaturated monomer to prepare a photochromic dye solution;
(c) The photochromic dye solution is dissolved in a water-soluble urethane (meth)acrylate oligomer composition.
As mentioned above, most photochromic dyes are oil-soluble (water-insoluble) due to their structure, so when applying photochromic dyes, they are generally dissolved in an organic solvent and applied to a substrate. However, if an organic solvent is used, for example, when applying to a plastic substrate, the organic solvent may dissolve the substrate. Furthermore, in terms of safety, it is preferable to use an aqueous solvent rather than an organic solvent.
For this reason, in the manufacturing method of the present invention, the photochromic dye-containing active energy ray curable water-soluble resin composition obtained is in a state in which the photochromic dye is dispersed in the water-soluble resin composition, but the solution stability can be made good. In addition, since it is water-soluble, it is easy to use. In other words, compared to those in which an organic solvent is used as the solvent, it is possible to avoid dissolving the plastic substrate, and by not using an organic solvent, it is possible to ensure greater safety. Furthermore, unlike conventional water-soluble photochromic polymers, it is possible to provide a cured coating film with excellent durability (water resistance, solvent resistance), and to provide an excellent hard coat property by suitably compensating for the scratch resistance, which can be said to be a weakness of plastics. In addition, it is possible to exhibit excellent properties such as optical transparency (total light transmittance, HAZE).

(a: Preparation of Water-Soluble Urethane (Meth)acrylate Oligomer Composition)
In order to prepare the water-soluble urethane (meth)acrylate oligomer composition of the present invention, first, a urethane (meth)acrylate oligomer represented by formula (1) is synthesized.
The urethane (meth)acrylate oligomer represented by formula (1) is
reacting 1 mole of an isocyanate compound having (m+n) isocyanate groups with n moles of a hydroxyl group-containing (meth)acrylate compound;
Next, a (meth)acrylic acid alkylene oxide adduct or a polyalkylene glycol compound having a hydroxyl group at one end is reacted in an m molar ratio to obtain the polyalkylene glycol.
(R ¹ O-CONH) _m -R ² -(NHCO-OR ³ ) _n (1)
(Wherein,
R ¹ O-- represents a dehydrogenation residue of a polyalkylene glycol compound having a hydroxyl group at one end or a (meth)acrylic acid alkylene oxide adduct;
^R2 is a residue of a deisocyanated group of an isocyanate compound,
R ³ O-- represents a dehydrogenated residue of a hydroxyl group-containing (meth)acrylate compound;
m and n each represent an integer between 1 and 50, provided that m≦n.
Then, water is added to the obtained urethane (meth)acrylate oligomer while gently stirring the interface between the urethane (meth)acrylate oligomer and the water, thereby producing a water-soluble urethane (meth)acrylate oligomer composition.

The emulsion obtained by the above-mentioned method for producing a water-soluble urethane (meth)acrylate oligomer composition in this application has an extremely small average particle size and is stable for a long period of time (no secondary aggregation occurs), while the coating film obtained by the composition containing this can be a coating film with excellent water resistance, solvent resistance, and scratch resistance. In other words, it has unique contradictory properties of being water-soluble before curing, but being highly water-resistant when cured. Such a coating film has excellent scratch resistance and antistatic properties, so it can protect the surface of a substrate such as plastic, prevent dust absorption, and even impart antibacterial properties. In addition, such a coating film has excellent anti-fogging properties because it has hydrophilic groups, and can be used to prevent fogging not only for plastics but also for glasses, mirrors, etc., and can have good dispersibility in water-based pigments. Furthermore, since the molecular weight of the urethane (meth)acrylate oligomer itself is relatively small, it can also be used as a component of a water-soluble UV inkjet ink.

Examples of the isocyanate compound having (m+n) isocyanate groups include diisocyanates and polyisocyanates of diisocyanate monomers.
Examples of diisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, (o-, m-, or p-)xylene diisocyanate, methylene bis(cyclohexyl isocyanate), trimethylhexamethylene diisocyanate, cyclohexane-1,3-dimethylene diisocyanate, cyclohexane-1,4-dimethylene isocyanate, 1,5-naphthalene diisocyanate, norbornane diisocyanate, etc. Examples of polyisocyanates of diisocyanate monomers include nurates of hexamethylene diisocyanate, nurates of isophorone diisocyanate, nurates of tolylene diisocyanate, and biuretized products of these diisocyanates. Among these, nurates of hexamethylene diisocyanate, nurates of isophorone diisocyanate, and nurates of tolylene diisocyanate, each of which has three or more isocyanate groups in one molecule, are more preferred.
The isocyanate compound may have a urethane structure in which an alcohol compound is added to one or more isocyanate groups contained therein, or a urea structure in which an amine compound is added. When an alcohol compound and an amine compound are added to an isocyanate group, the number of functional groups per molecule of the isocyanate compound can be increased. Examples of alcohol compounds that can be added to an isocyanate group include ethylene glycol, propylene glycol, tetramethylene glycol, glycerin, trimethylolpropane, and pentaerythritol. Examples of amine compounds include diaminoethane, diaminopropane, and tetramethylenediamine. It is preferable to use these alcohol compounds and amine compounds with a small molecular weight per functional group from the viewpoint of increasing the scratch resistance of the cured polymer.

Examples of hydroxyl group-containing (meth)acrylate compounds include hydroxyalkyl (meth)acrylates, polyol (meth)acrylates, and alkylene oxide-added polyol (meth)acrylates. Examples of hydroxyalkyl (meth)acrylates include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and hydroxyphenoxypropyl (meth)acrylate. Examples of polyol (meth)acrylates include glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate. Examples of alkylene oxide-added polyol (meth)acrylates include alkylene oxide-added trimethylolpropane di(meth)acrylate, alkylene oxide-added pentaerythritol tri(meth)acrylate, and alkylene oxide-added dipentaerythritol penta(meth)acrylate.

When reacting an isocyanate compound with a hydroxyl group-containing (meth)acrylate compound, in order to promote the reaction, it is preferable to stir the mixture in the presence of a metal catalyst such as dibutyltin dilaurate or an amine catalyst such as 1,8-diazabicyclo[5.4.0]undecene-7 at a temperature range of 50°C to 80°C, and more preferably at a temperature range of 60°C to 70°C.

Subsequently, the reaction product obtained above is reacted with an alkylene oxide (meth)acrylate adduct or a polyalkylene glycol compound having a hydroxyl group at one end.
The (meth)acrylic acid alkylene oxide adduct is preferably an alkylene oxide adduct of (meth)acrylic acid or a mono(meth)acrylate of polyalkylene glycol. The alkylene oxide adducts of (meth)acrylic acid are obtained by adding an alkylene oxide, such as ethylene oxide, propylene oxide, or butylene oxide, to (meth)acrylic acid. They can also be synthesized from polyalkylene glycol, such as polyethylene glycol, polypropylene glycol, or polytetramethylene glycol. The molecular weight of the (meth)acrylic acid alkylene oxide adduct can be selected arbitrarily, but is preferably 900 or more, and more preferably 900 to 2000. From another viewpoint, the number of moles of the alkylene oxide added is preferably 20 or more, and more preferably 20 to 35.
The polyalkylene glycol compound containing a hydroxyl group at one end is preferably an alkoxypolyethylene glycol. Examples of the alkoxypolyethylene glycol include methoxypolyethylene glycol, ethoxypolyethylene glycol, butoxypolyethylene glycol, polyethylene glycol monoallyl ether, polyethylene glycol monododecyl ether, polyethylene glycol monolaurate, and polyethylene glycol monooctyl ether. The molecular weight of the alkoxypolyethylene glycol can be selected arbitrarily, but is preferably 900 or more, and more preferably 900 to 2000. By using such a compound, the water-soluble urethane (meth)acrylate oligomer composition obtained can be a nonionic emulsion, and even when various additives are added to the coating composition, etc., the inhibition of the emulsion properties such as aggregation, precipitation, and separation can be prevented.

When the reaction product obtained above is reacted with an alkylene oxide (meth)acrylate adduct or a polyalkylene glycol compound containing a hydroxyl group at one end, the reaction is preferably carried out in the presence of a metal catalyst such as dibutyltin dilaurate at a temperature range of 50° C. to 80° C., more preferably at a temperature range of 60° C. to 70° C.
The resulting urethane (meth)acrylate oligomer can have a resin concentration of 100%. The weight average molecular weight of the urethane (meth)acrylate oligomer can be, for example, 5,000 to 100,000, and preferably 7,000 to 20,000. By using such a weight average molecular weight, a composition with an appropriate viscosity can be obtained, which is easily self-emulsified, and the water-soluble composition can be easily adjusted using the composition. In addition, when a coating film or the like containing such a water-soluble composition is formed, a coating film with high hardness can be obtained.
The weight average molecular weight means the weight average molecular weight calculated in terms of the molecular weight of standard polystyrene, and can be measured by using a high performance liquid chromatography (Shodex GPC system-11 type, manufactured by Showa Denko K.K.) with three columns in series: Shodex GPC KF-806L (exclusion limit molecular weight: 2×10 ⁷ , separation range: 100 to 2×10 ⁷ , theoretical plate number: 10,000 plates/column, packing material: styrene-divinylbenzene copolymer, packing particle size: 10 μm).

For example, when an isocyanate compound having (m+n) isocyanate groups is reacted with an (meth)acrylic acid alkylene oxide adduct or a polyalkylene glycol compound having a hydroxyl group at one end first, the polyalkylene glycol compound has a molecular weight distribution and contains polyalkylene glycols having hydroxyl groups at both ends as well as at one end, so gelation often occurs. When gelation occurs, not only is the reaction unable to proceed stably, but the resulting reaction product is also difficult to dissolve in water.
On the other hand, as described above, by first reacting an isocyanate compound having (m+n) isocyanate groups with n molar ratio of a hydroxyl group-containing (meth)acrylate compound and then reacting it with a (meth)acrylic acid alkylene oxide adduct compound or a polyalkylene glycol compound containing a hydroxyl group at one end, the polyalkylene glycol compound is bonded in a pendant-like manner to form a pendant-type urethane acrylate structure, which enables self-emulsification.

Next, water is added to the urethane (meth)acrylate oligomer represented by formula (1) to produce a water-soluble urethane (meth)acrylate oligomer composition in the form of an aqueous emulsion solution.
For this purpose, water is gradually added to the urethane (meth)acrylate oligomer obtained above. At this time, the obtained urethane (meth)acrylate oligomer is preferably maintained at a temperature in the range of, for example, 30° C. to 80° C., and the temperature of the water to be added is preferably adjusted to a similar range, more preferably to a temperature in the range of 40° C. to 70° C. or 40° C. to 60° C.
The water to be added may be tap water, deionized water, ion-exchanged water, distilled water, or other various waters. The water is preferably added by, for example, dropping or dividing. In the case of dividing, the amount of water added at one time may be, for example, 50 to 200 parts, preferably 100 to 200 parts, per 100 parts of urethane (meth)acrylate oligomer. The amount of water added is preferably an amount that results in a resin concentration of 50% by weight or less, more preferably 10 to 45% by weight, and even more preferably 15 to 40% by weight or 20 to 40% by weight. For example, the time required for the addition of water may be 5 minutes or more from the start to the end of the addition of water, and may be 5 to 2 hours, preferably 10 to 30 minutes or 15 to 30 minutes.

In addition, it is preferable to stir the mixture by arranging a stirring blade at the interface between the oligomer and water, that is, near the interface between the oligomer and water or slightly on the water side of the interface, at the same time as the addition of water. It is preferable to stir the mixture gently. In addition, since the stirring bar sinks to the bottom of the container and cannot be arranged at the interface between the oligomer and water, that is, the W/O interface, it is preferable to stir the mixture using a stirrer that can arrange a stirring blade near the interface between the oligomer and water. As the stirring blade, for example, a paddle blade can be used. The paddle blade can be arranged near the interface between the oligomer and water or slightly on the water side of the interface, and may have only one blade or may have two or more blades in multiple stages. As the gentle stirring, a rotation speed of 500 rpm or less can be mentioned, preferably 300 rpm or less, more preferably 200 rpm or less, and particularly preferably 100 rpm to 300 rpm or 100 rpm to 150 rpm.
Furthermore, it is preferable to continue stirring even after the addition of water is completed. The stirring in this case may be different from the stirring during the addition, but it is preferable to continue stirring at the same rate. After the addition of water is completed, for example, stirring can be continued for 10 minutes or more, preferably 20 minutes or more, and more preferably 30 minutes or more. The rotation speed at this time can also be in the same range as above.

By emulsifying by such an emulsification method (phase inversion emulsification), the obtained emulsion has an extremely small average particle size and high storage stability. In addition, when the emulsion is used as a coating composition, for example, after coating and drying to form a radiation-cured coating film, the obtained coating film has good leveling properties and extremely high water resistance, and while the oligomer before curing is water-soluble, the coating film after curing has high water resistance, so that a coating composition having both of these contradictory properties can be obtained. It has been confirmed that this is due to the fact that the particle size of the urethane (meth)acrylate oligomer in the obtained water-soluble urethane (meth)acrylate oligomer composition is made uniform fine particles. For example, in the particle size distribution of the emulsion particles, the particle size of 50% of the particles is 100 nm or less. In addition, the 50% particle size is preferably 60 nm or less, more preferably 50 nm or less, and even more preferably 10 nm to 45 nm. In addition, the particle size of 95% of the particles is 150 nm or less. Also, 95% of the particle diameter is preferably 140 nm or less, more preferably 120 nm or less, and even more preferably 30 nm to 115 nm. From another viewpoint, the arithmetic mean diameter may be 110 nm or less. Also, it is preferably 100 nm or less, more preferably 70 nm or less, and even more preferably 10 nm to 60 nm.
These values were obtained by measuring the particle size distribution of the emulsion using a dynamic light scattering particle size distribution measuring device (LB-500) manufactured by Horiba, Ltd.

The water-soluble urethane (meth)acrylate oligomer composition does not exclude the inclusion of an organic solvent, and may contain, for example, organic solvents such as ethyl acetate, butyl acetate, toluene, xylene, methanol, ethanol, propanol, butanol, acetone, methyl isobutyl ketone, methyl ethyl ketone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cellosolves, diacetone alcohol, etc. In this case, the amount is preferably 50 parts or less, more preferably 10 parts or less, per 100 parts by weight of the entire composition.

(b: Preparation of photochromic dye solution)
Any known photochromic dye can be used. Among them, an oil-based dye is preferable because it can more effectively exert the effects of the present invention. The oil-based dye here is one having a solubility in water of less than 1 g/l at 20° C.
Examples of the dye include inorganic compounds such as tungsten oxide (WO ₃ ) and silver halide (e.g., AgBr), and organic dyes such as spirobenzopyran, spirooxazine, spiropyran, azobenzene, fulgide, chromene, diarylethene, azo, anthraquinone, merocyanine, styryl, azomethine, quinone, quinophthalone, perylene, indigo, tetrazine, stilbene, and benzidine dyes. These may be those disclosed in U.S. Patent No. 2,400,877, JP-T-2002-527786, JP-A-2-28154, JP-A-62-288830, WO94/22850, WO96/14596, etc. Among them, spirobenzopyran-based and diarylethene-based photochromic materials are preferred, and diarylethene-based photochromic materials are more preferred, because, in particular, molecules of all colors can be obtained by introducing a substituent and a condensed ring, it is easy to design molecules that are stable in both colorless and colored forms without thermal reversion at room temperature, and they exhibit stable photochromism not only in solution but also in crystals.
Spirobenzopyran-based photochromic materials include:
1',3'-Dihydro-8-methoxy-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-[2H]indole] (CAS RN 1498-89-1), 1,3,3-Trimethylindolinonaphthospirooxazine (CAS RN 27333-47-7), 1-(2-Hydroxyethyl)-3,3-dimethylindolino-6'-itrobenzopyrylospiran (CAS RN 16111-07-2), 1,3,3-Trimethylindolinobenzopyrylospiran (CAS RN 1485-92-3), 1,3,3-Trimethylindolino-8'-methoxybenzopyrylospiran (CAS RN 13433-31-3), 1,3,3-Trimethylindolino-6'-nitrobenzopyrylospiran (CAS RN 1498-88-0), 1,3,3-Trimethylindolino-β-naphthopyrylospiran (CAS RN 1592-43-4), 1,3,3-Trimethylindolino-6'-bromobenzopyrylospiran (CAS RN 16650-14-9) etc.
Photochromic diarylethene materials include 2,3-Bis(2,4,5-trimethyl-3-thienyl)maleimide (CAS RN 220191-36-6), 2,3-Bis(2,4,5-trimethyl-3-thienyl)maleic anhydride (CAS RN 112440-47-8), 1,2-Bis(2,4-dimethyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluoro-1-cyclopentene (CAS RN 172612-67-8), and cis-1,2-Dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene (CAS RN 112440-46-7), 1,2-Bis[2-methylbenzo[b]thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene (CAS RN 137814-07-4), 1,2-Bis[2-methylbenzo[b]thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene (CAS RN 137814-07-4), and the like.

Examples of the ethylenically unsaturated monomer include a (meth)acrylic acid compound and a vinyl group-containing compound.
Examples of the (meth)acrylic acid compound include acrylic acid amides, alkyl (meth)acrylates, aminoalkyl (meth)acrylates, quaternary salts of aminoalkyl (meth)acrylates, alkoxy polyalkylene glycol (meth)acrylates, hydroxyalkyl (meth)acrylates, acid anhydride adducts of hydroxyalkyl (meth)acrylates, polyalkylene glycol di(meth)acrylates, alkyldiol di(meth)acrylates, polyol poly(meth)acrylates, alkylene oxide adduct polyol poly(meth)acrylates, etc. Examples of the vinyl group-containing compound include vinyl acetate, N-vinyl acetamide, vinyl pyrrolidone, vinyl alkyl ethers, vinyl sulfonic acid, and salts of vinyl sulfonic acid. These may be used alone or in combination of two or more.

Examples of acrylic acid amides include (meth)acryloyl morpholine and dimethylaminoalkyl (meth)acrylamide. Examples of aminoalkyl (meth)acrylates include diethylaminoethyl (meth)acrylate. Examples of quaternary salts of aminoalkyl (meth)acrylates include alkyloylaminopropyldimethyl-2-hydroxyethylammonium salt. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. Examples of alkoxy polyalkylene glycol (meth)acrylates include methoxy polyethylene glycol (meth)acrylate and methoxy polypropylene glycol (meth)acrylate. Examples of hydroxyalkyl (meth)acrylates include hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate. Examples of the acid anhydride adduct of hydroxyalkyl (meth)acrylate include hydroxyethyl (meth)acrylate phthalic anhydride adduct, hydroxyethyl (meth)acrylate succinic anhydride adduct, hydroxyethyl (meth)acrylate tetrahydrophthalic anhydride adduct, hydroxyethyl (meth)acrylate hexahydrophthalic anhydride adduct, hydroxypropyl (meth)acrylate phthalic anhydride adduct, hydroxypropyl (meth)acrylate succinic anhydride adduct, hydroxypropyl (meth)acrylate tetrahydrophthalic anhydride adduct, and hydroxypropyl (meth)acrylate hexahydrophthalic anhydride adduct. Examples of polyalkylene glycol di(meth)acrylates include polyethylene glycol di(meth)acrylate and polypropylene glycol di(meth)acrylate. Examples of alkyl diol di(meth)acrylates include butane diol di(meth)acrylate and hexane diol di(meth)acrylate. Examples of polyol poly(meth)acrylates include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. Examples of alkylene oxide-added polyol poly(meth)acrylates include alkylene oxide-added trimethylolpropane tri(meth)acrylate, alkylene oxide-added pentaerythritol tri(meth)acrylate, alkylene oxide-added pentaerythritol tetra(meth)acrylate, alkylene oxide-added pentaerythritol hexa(meth)acrylate, etc. Examples of vinyl alkyl ethers include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, amyl vinyl ether, 2-ethylhexyl vinyl ether, etc.

Among these, the (meth)acrylic acid compound or vinyl group-containing compound is more preferably (meth)acryloylmorpholine, vinylpyrrolidone, dimethylaminoalkyl (meth)acrylate, quaternary salt of dimethylaminoalkyl (meth)acrylate, dimethylaminoalkyl (meth)acrylamide, N-vinylacetamide, vinylsulfonic acid, or vinylsulfonate, which have antistatic properties.

The method for dissolving the photochromic dye in the ethylenically unsaturated monomer is not particularly limited, and may be, for example, by adding the photochromic dye to the ethylenically unsaturated monomer and stirring the mixture. In this case, the mixture may be heated to, for example, room temperature to 80°C, preferably 40°C to 70°C or 50°C to 60°C.
The ratio (parts by weight) of the ethylenically unsaturated monomer/photochromic dye is preferably 0.001 to 4 parts, more preferably 0.005 to 0.3 parts, of the photochromic dye per 100 parts of the ethylenically unsaturated monomer.

(c: Dissolution of photochromic dye solution in water-soluble urethane (meth)acrylate oligomer composition)
The method for dissolving the photochromic dye solution in the water-soluble urethane (meth)acrylate oligomer composition is not particularly limited, and may be, for example, by adding the photochromic dye solution to the water-soluble urethane (meth)acrylate oligomer composition and stirring it. In this case, the mixture may be heated to, for example, room temperature to 80°C, preferably 40°C to 70°C or 50°C to 60°C.
The ratio (ratio of solids) of the photochromic dye solution to the water-soluble urethane (meth)acrylate oligomer composition is preferably 5 to 300 parts, and more preferably 50 to 250 parts, of the photochromic dye solution per 100 parts of solids of the water-soluble urethane (meth)acrylate oligomer composition.

Coating Composition
The photochromic dye-containing active energy ray-curable water-soluble resin composition obtained by the method for producing a photochromic dye-containing active energy ray-curable water-soluble resin composition in the present application can be made into a coating composition by optionally containing at least one of an ethylenically unsaturated monomer, a photopolymerization initiator, a photopolymerization initiator assistant, an antistatic agent, etc. Among them, those containing a photopolymerization initiator are preferred.
However, these components may be added to the photochromic dye solution and/or to the water-soluble urethane (meth)acrylate oligomer composition of the photochromic dye solution when preparing the above-mentioned photochromic dye solution and/or when dissolving the photochromic dye solution in the water-soluble urethane (meth)acrylate oligomer composition, respectively. In this case, these components may be added simultaneously or sequentially to the water-soluble urethane (meth)acrylate oligomer composition and/or to the photochromic dye solution and mixed.
The ethylenically unsaturated monomer is used when preparing the above-mentioned photochromic dye solution, but may also be added when dissolving the photochromic dye solution in the water-soluble urethane (meth)acrylate oligomer composition and/or in the finally obtained dye-containing composition. However, since photopolymerization initiators and the like are relatively oil-soluble, it is preferable to add and dissolve them in the ethylenically unsaturated monomer of the photochromic dye solution, and then add and mix them in the water-soluble urethane (meth)acrylate oligomer. In addition, when an ethylenically unsaturated monomer is separately added to the water-soluble urethane (meth)acrylate oligomer composition and/or the dye-containing composition, it is preferable to add it within the range of the mass ratio to the photochromic dye mentioned in the preparation of the photochromic dye solution.
In other words, the amount of the ethylenically unsaturated monomer is 3 to 300 parts relative to 100 parts (solid content 30% by weight) of the water-soluble urethane (meth)acrylate oligomer composition, preferably 5 to 300 parts, and more preferably 10 to 200 parts. However, the amount of the ethylenically unsaturated monomer here includes the amount of the ethylenically unsaturated monomer used when preparing the photochromic dye solution described below.

When a photopolymerization initiator is added to the coating composition, the amount is 0.1 to 10 parts, preferably 0.5 to 10 parts, more preferably 2 to 8 parts, and particularly preferably 3 to 5 parts, relative to 100 parts of the curing components of the coating composition [solid content of the water-soluble urethane (meth)acrylate oligomer composition+ethylenically unsaturated monomer].
When a photopolymerization initiation aid is added to the photopolymerization initiator, the amount of the photopolymerization initiation aid is 0.1 to 100 parts per 100 parts of the photopolymerization initiator.
When an antistatic agent is added to the coating composition, the amount is 0 to 30 parts, preferably 0.01 to 20 parts, more preferably 0.05 to 10 parts, and particularly preferably 0.1 to 5 parts, based on 100 parts of the coating composition (solid content 30% by weight).

The photopolymerization initiator can be added to the dye-containing composition and/or the coating composition, for example, to crosslink and/or polymerize the urethane (meth)acrylate oligomer and the ethylenically unsaturated monomer by irradiating them with active energy rays to form a cured polymer. This cured polymer exhibits excellent scratch resistance, surface hardness, and adhesion to plastic substrates.
For example, when a polyalkylene glycol compound containing a hydroxyl group at one end that does not have a polymerizable functional group is used during the synthesis of a urethane (meth)acrylate oligomer, if the ratio of this compound is increased, the curing property decreases when crosslinked and the hardness also tends to decrease. Therefore, it is preferable to set the molar ratio of the polyalkylene glycol compound containing a hydroxyl group at one end to the molar ratio of the (meth)acrylate compound containing a hydroxyl group or less. The larger the molecular weight of the polyalkylene glycol chain, the greater the antistatic effect when crosslinked, but the lower the hardness tends to be. In addition, the greater the number of functional groups in the (meth)acrylate compound containing a hydroxyl group, the greater the hardness when crosslinked, and conversely, the fewer the number, the lower the hardness. By adjusting these, a cured polymer with an appropriate hardness can be obtained.

The photopolymerization initiator is not particularly limited as long as it generates radicals by the action of light, and examples thereof include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylenephenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzyl dimethyl Ketals, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, camphorquinone, dibenzosuberone, 2-ethylanthraquinone, 4',4"-diethylisophthalophenone, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, α-acyloxime ester, acylphosphine oxide, methylphenyl glyoxylate, benzyl, 9,10-phenanthrenequinone, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, etc.

In particular, in order to better exert the function as a dye-containing composition, it is preferable to use a photopolymerization initiator that is water-soluble or water-dispersible. Examples of such photopolymerization initiators include 2-(3-dimethylamino-2-hydroxypropoxy)-3,4-dimethyl-9H-thioxanthone-9-one methochloride (manufactured by Octel Chemicals, "Quantacure QTX"), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (manufactured by Ciba Specialty Chemicals, "Irgacure 2959"), and the like. Among these, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (manufactured by Ciba Specialty Chemicals, "Irgacure 2959") is more preferable.

Examples of photopolymerization initiator aids include triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michler's ketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, ethyl 4-dimethylaminobenzoate, (n-butoxy)ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone.

The antistatic agent acts synergistically with the antistatic effect of the cured polymer when crosslinked, and can significantly improve the antistatic effect. By setting the content of the antistatic agent within the following range, for example, the antistatic agent is not lost from the cured polymer when crosslinked, and a sufficient antistatic effect can be achieved.
Examples of the antistatic agent include cationic antistatic agents of quaternary ammonium salts, at least one anionic antistatic agent selected from aliphatic sulfonates, higher alcohol sulfates, higher alcohol alkylene oxide adduct sulfates, higher alcohol phosphates, and higher alcohol alkylene oxide adduct phosphates, and at least one nonionic antistatic agent selected from higher alcohol alkylene oxide adducts and polyalkylene glycol fatty acid esters. Of these, cationic antistatic agents are preferred.

The coating composition may further contain fillers, dyes and pigments, oils, plasticizers, waxes, drying agents, dispersants, wetting agents, emulsifiers, gelling agents, stabilizers, defoamers, leveling agents, thixotropic agents, antioxidants, flame retardants, antistatic agents, fillers, reinforcing agents, matting agents, crosslinking agents, etc. Any of the above-mentioned agents commonly used in the field may be used.

Examples of substrates to which the coating composition is applied include substrates such as plastics (e.g., polyolefin resins such as polyethylene, polypropylene, and polycyclopentadiene, polycarbonate, polyester, ABS resin, and acrylic resin), glass, paper, wood, and cement.
When the coating composition is applied to the surface of an object to be coated, the thickness is, for example, 1 μm to 50 μm, and preferably 5 μm to 20 μm. Prior to irradiation with active energy rays, the coating composition is preferably dried at a temperature exceeding 60° C., preferably at least 70° C., more preferably at least 80° C. and not more than 100° C., for 1 to 5 minutes, and preferably 3 to 5 minutes.
Thereafter, the coating composition can be crosslinked/polymerized by irradiating it with light such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, or active energy rays such as X-rays and γ-rays.
The crosslinked/polymerized coating composition can form, for example, a layer having photochromic properties that develop color under ultraviolet light and hard coat properties as an integrated layer. That is, as described above, by drying at a relatively high temperature and in a short time, the leveling properties of the coating film surface can be improved, and the steel wool resistance can also be improved. In addition, the coating composition has antistatic properties.
Therefore, the coating composition is very useful as a material for forming various coating films, such as paints, pressure sensitive adhesives, adhesives, tackifiers, release agents, inks, protective coating agents, anchor coating agents, magnetic powder coating binders, coatings for sandblasting, printing plates, etc. Furthermore, it can be used as a light control material, an ultraviolet indicator, a memory material for optical signals, a display material, a toy, a material for controlling the amount of light such as glass curtains, a photosensitive material which can be repeatedly used in the process of producing photographic printing plates, etc.
An article coated with the coating composition and cured has excellent abrasion resistance and antistatic properties, and therefore can protect the surface of a substrate such as plastic and prevent dust attraction. In addition, the coating composition has excellent antifogging properties and can be used to prevent fogging not only of plastics but also of glasses, mirrors, etc. In this case, the coating composition may be cured with active energy rays and/or heat to be molded into a plastic lens or the like, or may be applied to the surface of a lens or the like, or may be applied to an optical sheet or film and then attached to the lens surface.

Hereinafter, examples of the present invention will be described in detail.
Synthesis Example 1: Water-soluble urethane (meth)acrylate oligomer composition (Production of urethane (meth)acrylate oligomer composition)
Into a four-neck flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a dry air inlet, 159 g (0.29 mol) of hexamethylene diisocyanate trimer (isocyanate group content 23%), 0.6 g of 2,6-di-tert-butylcresol, and 0.02 g of dibutyltin dilaurate were charged. Dipentaerythritol pentaacrylate (0.58 mol) (545 g of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (hydroxyl value 59.8 mgKOH/g) was charged) was added dropwise to the flask at 70° C. over about 1 hour, and the mixture was allowed to react at 70° C. for 4 hours. When the remaining isocyanate group reached 1.7%, the mixture was cooled to 60° C.
Further, 643.9 g (0.30 mol) of polyethylene glycol monomethyl ether (weight average molecular weight 989.59, hydroxyl value 56.7 mgKOH/g) was added dropwise at 55° C. over about 1 hour. When the reaction started, intense heat was generated, so cooling was performed as necessary. When the heat generation almost ceased, the mixture was heated to 70° C. and reacted for 3 hours. The infrared absorption spectrum of the oligomer was measured, and the reaction was terminated when the absorption spectrum of the isocyanate group (2280 cm ⁻¹ ) disappeared, to obtain a urethane acrylate oligomer (resin concentration 100%).
The weight average molecular weight of the resulting urethane acrylate oligomer was 12,000.

(Emulsification)
300 g of the urethane acrylate oligomer obtained above was kept at 60°C, and 700 g of ion-exchanged water at room temperature (25°C) was added dropwise or in five separate portions (initial 400 g, 100 g added every 30 minutes) (phase inversion emulsification method) while stirring with a paddle blade near the interface between the oligomer and the ion-exchanged water (W/O interface). Stirring was performed at 100 to 150 rpm. Dropping was stopped when the resin concentration reached 30%, and an emulsion was obtained. Stirring was then maintained for 30 minutes, and a water-soluble urethane (meth)acrylate oligomer composition was obtained.
The resulting water-soluble urethane (meth)acrylate oligomer composition had a pH of 4 to 5, a heating residue (hereinafter also referred to as "resin concentration") of 30% by weight, and a viscosity at 25°C of 10 mPa·S.
The heating residue and viscosity are values measured by the following methods.

(Heating residue)
Accurately measure the weight of an aluminum dish (diameter approximately 50 mm) (Ag), place approximately 1.5 g of the sample on the aluminum dish, quickly spread it as evenly as possible over the entire bottom surface with a glass rod, and then accurately measure the mass (Bg). Dry the aluminum dish in an electric constant temperature dryer at 105°C to 110°C for 3 hours. Remove the aluminum dish from the dryer and allow it to cool to room temperature, then accurately measure its weight (Cg).
Heating residue (%) = 100 x {(C-A)/(B-A)}
Here, A is the weight of the aluminum dish (g), B is the weight of the aluminum dish including the sample before drying (g), and C is the weight of the aluminum dish including the sample after drying (g).
(viscosity)
Place approximately 400 ml of sample in a wide-mouthed bottle, cover it, place it in a thermostatic bath adjusted to the temperature "specified in the quality standard," and leave it for at least four hours to adjust the temperature of the sample. Place a rotor "specified in the quality standard" that has been kept at a specified temperature of ±0.2°C in a B-type rotational viscometer into the sample while being careful not to allow air bubbles to adhere to it, attach the rotor to the viscometer, and align the liquid level with the marked line. Set the rotation speed "specified in the quality standard," rotate the viscometer, and read the pointer reading after one minute.
Viscosity (mPa・S) = Pointer reading x X
Here, X is a viscosity conversion multiplier (according to the conversion table attached to the B-type rotational viscometer).

Synthesis Example 2 Photochromic Dye Solution 0.032 parts of a spiropyran photochromic dye (TPC-0144, manufactured by Yamada Chemical Co., Ltd.) was added as a photochromic dye to 100 parts of acryloylmorpholine as an ethylenically unsaturated monomer, and dissolved by heating at 60° C. to obtain a photochromic dye solution.
Synthesis Example 3 Photochromic Dye Solution 0.08 parts of a spiropyran photochromic dye (TPC-0144, manufactured by Yamada Chemical Co., Ltd.) was added as a photochromic dye to 100 parts of N,N-dimethylacrylamide as an ethylenically unsaturated monomer, and dissolved by heating at 60° C. to obtain a photochromic dye solution.

Example 1
The photochromic dye solution obtained in Synthesis Example 2 was added to 100 parts of the solid content of the water-soluble urethane (meth)acrylate oligomer composition obtained in Synthesis Example 1 (resin content concentration: 30% by weight) so that the ethylenically unsaturated monomer and the photochromic dye were 50 parts and 0.016 parts, respectively, of the composition, and the mixture was dissolved by heating at 60° C. to obtain an active energy ray-curable water-soluble resin composition containing a photochromic dye (resin content concentration: 39% by weight).

Example 2
Instead of acryloylmorpholine, which is an ethylenically unsaturated monomer in Example 1, N,N-dimethylacrylamide was mixed and dissolved in the same manner as in Synthesis Example 2 to obtain a photochromic dye solution, and further, using this, an active energy ray-curable water-soluble resin composition containing a photochromic dye was obtained in the same manner as in Example 1 (resin concentration: 39% by weight).

Example 3
The photochromic dye solution obtained in Synthesis Example 3 was added to 100 parts of the solid content of the water-soluble urethane (meth)acrylate oligomer composition obtained in Synthesis Example 1 (resin content concentration: 30% by weight) so that the ethylenically unsaturated monomer was 200 parts and the photochromic dye was 0.04 parts, and the mixture was heated and dissolved at 60° C. to obtain an active energy ray-curable water-soluble resin composition containing a photochromic dye (resin content concentration: 56% by weight).

Comparative Example 1
Except for the ethylenically unsaturated monomer in Example 1, 0.04 parts of a spiropyran photochromic dye (TPC-0144, manufactured by Yamada Chemical Co., Ltd.) was added to 100 parts of the solid content of a water-soluble urethane (meth)acrylate oligomer composition (resin content concentration: 30% by weight), and the mixture was mixed and dissolved at 60°C to obtain an active energy ray-curable water-soluble resin composition (resin content concentration: 30% by weight).
Comparative Example 2
0.03 parts of a spiropyran photochromic dye (TPC-0144, manufactured by Yamada Chemical Co., Ltd.) was added to 100 parts of N,N-dimethylacrylamide as an ethylenically unsaturated monomer and mixed and dissolved at 60°C, and then ion-exchanged water was added in place of the water-soluble urethane (meth)acrylate oligomer composition to obtain an active energy ray-curable water-soluble resin composition (resin concentration 40% by weight).

Test Example A
The active energy ray-curable water-soluble resin compositions of Examples 1 to 3 and Comparative Examples 1 and 2 obtained above were evaluated as follows.
(Solution stability of aqueous emulsion)
The above active energy ray curable water-soluble resin composition was kept at 60°C and stirred with a stirrer for 10 minutes, and the obtained aqueous emulsion was left to stand at room temperature and 60°C for one month, and the presence or absence of layer separation and sediment was visually confirmed. If there was no layer separation or sediment, it was a homogeneous aqueous solution and was evaluated as stable. In addition, the comparative example in which no aqueous emulsion was obtained was judged to be insoluble, and the storage stability of the aqueous emulsion was not evaluated. The results are shown in Table 1.

Example 4: UV-curable water-soluble resin coating agent [0213] 4 parts of 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (manufactured by Ciba Specialty Chemicals, "Irgacure 2959") as a photopolymerization initiator was added to and mixed with 100 parts of the water-soluble urethane (meth)acrylate oligomer composition obtained in the Examples and Comparative Examples and the ethylenically unsaturated monomer combined for a total solid content of 100 parts, to obtain a UV-curable water-soluble resin coating agent.

Test Example B
The UV-curable water-soluble resin coating agent obtained above was subjected to the following evaluations.
(Photochromic performance)
The coating agents using the urethane (meth)acrylate oligomer compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were applied to an ABS plate using a #16 bar coater so that the film thickness after drying was 10 μm, and dried at 80° C. for 3 minutes. Then, ultraviolet light was irradiated using an electrodeless lamp H bulb at a line speed of 5.4 m/min, an irradiation amount of 600 mJ/cm ² , and a peak illuminance of 1,500 mW/cm ² . At this time, it was visually observed that the color developed in red, and then the color faded when left undisturbed for one day under light shielding. If the color developed under UV and faded under light shielding, the photochromic performance was evaluated and indicated as ◯ in Table 1.
In addition, when the coating agent of Comparative Example 2 was applied to the ABS plate, repelling occurred and the coating could not be applied uniformly.
(Adhesion to substrate)
The coating agents using the urethane (meth)acrylate oligomer compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were applied onto various plastic panels using a bar coater No. 16 so that the film thickness after drying would be 10 μm, and then dried for 3 minutes at 80° C. Then, using an electrodeless lamp H bulb, ultraviolet light was irradiated at a line speed of 5.4 m/min, an irradiation amount of 600 mJ/cm ² , and a peak illuminance of 1,500 mW/cm ² to form cured coating films.
According to JIS K5400, 100 2 mm squares were made on the cured coating film, and an adhesion test was performed using cellophane tape. The peeling state of the squares was observed and evaluated based on the number of remaining squares.
(Scratch resistance)
In order to test the adhesion to the substrate, the coating film on an easily adhesive PET film (Toyobo A4300, 125 μm) was rubbed 10 times with steel wool (#0000) under a load of 500 g. The state of scratches was evaluated by visual observation and the results are shown in Table 1.
(Pencil hardness)
The coating agent using the urethane (meth)acrylate oligomer composition obtained in Examples 1 to 3 and Comparative Examples 1 and 2 was applied to an easily adhesive PET film (Toyobo A4300, 125 μm) using a #16 bar coater so that the film thickness after drying would be 10 μm, and dried at 80° C. for 3 minutes. Thereafter, the film was irradiated with ultraviolet light using an electrodeless lamp H bulb at a line speed of 5.4 m/min, an irradiation amount of 600 mJ/cm ² , and a peak illuminance of 1,500 mW/cm ² to form a cured coating film. The pencil hardness of the cured coating film was measured in accordance with JIS K5400.
(Cure shrinkage)
A coating film was formed in the same manner as in the pencil test, and immediately after curing, the coating film was cut into a 10 cm x 10 cm square with a film thickness of 10 μm and left overnight. The jump height was measured at four points on the end face and the average value was calculated. The values are shown in Table 1 (unit: mm). A value of less than 1.5 cm is considered to be acceptable.
(Flexibility (Mandrel test))
A coating film was formed in the same manner as in the pencil test, and the cured coating film was dried and measured for flexibility until cracks appeared using a mandrel tester. The diameter (mm) φ at which no cracks appeared in the coating film is shown in Table 1.
(Optical properties)
A coating film was formed in the same manner as in the pencil test, and the total light transmittance, HAZE and YI of the dried and cured coating film (on highly adhesive PET (A-4300)) were measured using a spectrophotometer CM-3600A manufactured by Konica Minolta. The results are shown in Table 1.
Total light transmittance: 89% or more is acceptable (A-4300: 89.34 or higher);
HAZE: 1.0 or less is acceptable (A-4300: 0.70 or above),
YI (after color development): 1.5 or less was considered to be acceptable (A-4300: 1.0 or above).
(Rubbing test: water resistance, solvent resistance)
A coating film was formed in the same manner as in the pencil test, and one drop of water, ethanol, or methyl ethyl ketone (MEK) was dropped onto the dried, cured coating film (on highly adhesive PET (A-4300)), and the film was rubbed back and forth 10 times with gauze under a load of about 1 kg. The presence or absence of changes in the coating film was evaluated by visual observation.

表１中、ＡＣＭＯは、アクリロイルモルフォリン（ＫＪケミカルズ社製）、
ＤＭＡＡは、Ｎ，Ｎ－ジメチルアクリルアミド（ＫＪケミカルズ社製）を表す。
表１中、（）は固形分を表す。［］は水溶性ウレタンアクリレート組成物の固形分を１００部とした場合の重量部を表す。

In Table 1, ACMO is acryloylmorpholine (manufactured by KJ Chemicals),
DMAA represents N,N-dimethylacrylamide (KJ Chemicals).
In Table 1, ( ) indicates the solid content, and [ ] indicates parts by weight when the solid content of the water-soluble urethane acrylate composition is 100 parts.

Claims (15)

reacting 1 mole of an isocyanate compound having (m+n) isocyanate groups with n moles of a hydroxyl group-containing (meth)acrylate compound;
Next, the resulting reaction product is reacted with an alkylene oxide (meth)acrylate adduct or a polyalkylene glycol compound having a hydroxyl group at one end in an amount of m moles,
Obtaining a urethane (meth)acrylate oligomer represented by formula (1),
While adding water to the urethane (meth)acrylate oligomer, the interface between the urethane (meth)acrylate oligomer and the water is gently stirred at a speed of 200 rpm or less to emulsify the mixture , thereby preparing a water-soluble urethane (meth)acrylate oligomer composition;
preparing a photochromic dye solution by dissolving a photochromic dye in an ethylenically unsaturated monomer;
The photochromic dye solution is dissolved in the water-soluble urethane (meth)acrylate oligomer composition.
(R ¹ O-CONH) _m -R ² -(NHCO-OR ³ )n (1)
(Wherein,
R ¹ O-- represents a dehydrogenation residue of a polyalkylene glycol compound having a hydroxyl group at one end or a (meth)acrylic acid alkylene oxide adduct;
^R2 is a residue of a deisocyanated group of an isocyanate compound,
^-OR3 is a dehydrogenated residue of a hydroxyl group-containing (meth)acrylate compound,
m and n each represent an integer between 1 and 50, provided that m≦n. The method according to claim 1, wherein the ethylenically unsaturated monomer is water-soluble. The method according to claim 1 or 2, wherein the ethylenically unsaturated monomer has a homopolymer glass transition temperature of 100°C or higher. The method according to any one of claims 1 to 3, wherein the photochromic dye is at least one selected from spirobenzopyran derivatives and diarylethene derivatives. The method according to any one of claims 1 to 4, wherein the isocyanate compound is a diisocyanate or a polyisocyanate of a diisocyanate monomer. The method according to any one of claims 1 to 5, wherein the polyalkylene glycol compound containing a hydroxyl group at one end is an alkoxy polyalkylene glycol. The method according to any one of claims 1 to 6, wherein the (meth)acrylic acid alkylene oxide adduct is a compound obtained by adding (meth)acrylic acid to an alkylene oxide or by mono(meth)acrylate of a polyalkylene glycol. The method according to any one of claims 1 to 7, wherein the hydroxyl group-containing (meth)acrylate compound is a hydroxyalkyl (meth)acrylate, a polyol (meth)acrylate, or an alkylene oxide-added polyol (meth)acrylate. The method according to any one of claims 1 to 8, wherein the ethylenically unsaturated monomer is a (meth)acrylic acid compound or a vinyl group-containing compound. The method according to claim 9, wherein the (meth)acrylic acid compound is at least one selected from acrylic acid amides, alkyl (meth)acrylates, aminoalkyl (meth)acrylates, quaternary salts of aminoalkyl (meth)acrylates, alkoxy polyalkylene glycol (meth)acrylates, hydroxyalkyl (meth)acrylates, acid anhydride adducts of hydroxyalkyl (meth)acrylates, polyalkylene glycol di(meth)acrylates, alkyldiol di(meth)acrylates, polyol poly(meth)acrylates, and alkylene oxide-added polyol poly(meth)acrylates, and the vinyl group-containing compound is at least one selected from vinyl acetate, N-vinyl acetamide, vinyl pyrrolidone, vinyl alkyl ethers, vinyl sulfonic acid, and salts of vinyl sulfonic acid. The method according to any one of claims 1 to 10, wherein the solids ratio (weight ratio) of the water-soluble urethane (meth)acrylate oligomer composition, the ethylenically unsaturated monomer, and the photochromic dye is 100:5-300:0.005-0.2. A coating composition comprising an active energy ray-curable water-soluble resin composition containing a photochromic dye obtained by the manufacturing method according to any one of claims 1 to 11. The coating composition according to claim 12, further comprising at least one photopolymerization initiator. The coating composition according to claim 13 , wherein the photopolymerization initiator is contained in an amount of 0.002 to 10 parts by weight based on 100 parts by weight of the total solid content of the water-soluble urethane (meth)acrylate oligomer composition and the ethylenically unsaturated monomer. A cured article comprising: a substrate; and a film of the coating composition according to any one of claims 12 to 14 formed on the surface of the substrate.