JP5159175B2 - Urethane (meth) acrylate-based compound, active energy ray-curable composition, and use thereof - Google Patents

Description

  The present invention relates to a novel urethane (meth) acrylate compound, and more specifically, a cured product having a high refractive index, excellent accuracy of the refractive index of the compound, and excellent hardness and adhesion to a substrate. The present invention relates to a urethane (meth) acrylate compound useful for forming an active energy ray, an active energy ray-curable composition containing the compound, and a coating agent and a lens forming agent.

In recent years, with the progress of the optical industry such as displays, optical communications, and solar cells, a transparent resin having excellent optical performance has been demanded. Among them, there is a strong demand for coating materials and lens forming materials. For example, many materials for forming a coating layer having a high refractive index have been proposed.
On the other hand, in the coating field, materials that can be cured with active energy rays are widely used because of excellent adhesion to various plastic films, glass, metals, etc., and good productivity. Various (meth) acrylate compounds are widely used.

  Under such circumstances, in order to cope with diversification of optical functions and improvement of productivity, a material having both a high refractive index and a fast curing property has been demanded. For example, an aromatic ring and a sulfur atom are included in the molecular structure. (Meth) acrylate-based compounds (for example, see Patent Documents 1 and 2), and urethane (meth) acrylate-based compositions that have a urethane bond in the molecular structure and have improved adhesion to the substrate. A thing (for example, refer patent document 3) is proposed.

JP 61-072748 A Japanese Unexamined Patent Publication No. 62-195357 JP 2006-291148 A

However, in the disclosed technologies of Patent Documents 1 and 2, since there is no structural unit that improves adhesion such as a urethane group in the molecular structure, the adhesion with the base material is poor when used as a coating agent. .
In the disclosed technique of Patent Document 3, since the refractive index is about 1.58 to 1.59, it has not yet been satisfied with the recent demand for higher refractive index. It is very difficult to produce a single compound, and it cannot be obtained as a single compound, but has a molecular weight distribution, resulting in variations in the refractive index of the compound (composition) and resulting curing The refractive index of the object was likely to fluctuate.
In addition, the refractive index in this invention is a value measured at 23 degreeC using a NaD line | wire.

  In recent years, in the optical field, demand for optical components with a low-reflection coating has increased. Examples thereof include various types of lenses such as a transparent substrate for display, an optical film, and glasses. In these optical components, it is important to improve the light transmittance, and particularly in display applications, it is important to reduce the reflectance of the surface even by 0.1% in order to improve luminance and reduce power consumption. It is.

As a technique for lowering the reflectance, a technique for providing a low refractive index coating layer on the surface of the base material, and a high refractive index coating layer and a low refractive index coating layer on the surface of the base material for the purpose of further reducing the reflectance A method of alternately laminating is used. In these methods, it is necessary to accurately form a coat layer having a target refractive index according to a strict optical calculation.
In addition, the reflectance mentioned here is a reflectance when natural light is obtained perpendicularly to the coat layer from the air layer.

  Taking an optical film for display as an example, a polyethylene terephthalate (PET) film having a refractive index of 1.7 is widely used as a base material, and the reflectance of its surface is 6.7% according to Fresnel's law. The surface of the PET film is often treated with an acrylic hard coat agent having a refractive index of about 1.5, and the reflectance in this case is 4.4%. Furthermore, the reflectance is 4.2 by adopting a layer structure of PET base material (refractive index 1.7) / high refractive index coat layer (refractive index 1.6) / hard coat layer (refractive index 1.5). % Can be reduced.

The problem in such a case is the refractive index accuracy of the high refractive index coating layer. For example, in the above-described three-layer configuration, the reflectance is lowest when the refractive index of the high refractive index coating layer is 1.60, but even when the refractive index is as large as 1.61, it is also 1.59. Even if it becomes smaller, the reflectance increases. Therefore, it is necessary to adjust the refractive index of the coat layer with accuracy within ± 0.005.
Factors that cause the refractive index to fluctuate include that the chemical structure and the component ratio of each component constituting the coating agent are not constant, the degree of polymerization of the cured product is not constant, or the incorporation of impurities. Among these, the fluctuation caused by the chemical structure is an essential problem. For example, when an oligomer having a molecular weight distribution is used as a constituent component, the refractive index tends to fluctuate. This is because the oligomer is an aggregate of compounds having a plurality of chemical structures, and the composition is likely to vary from production lot to production lot.

  In the present invention, in such a background, to form a cured product having low viscosity, high refractive index, excellent refractive index accuracy, and excellent hardness and adhesion to a substrate. An object of the present invention is to provide a useful urethane (meth) acrylate compound and an active energy ray-curable composition containing the same.

の構造を有し、更に、左右に１個ずつのウレタン結合を有することにより、低粘度で、高屈折率を有し、かつ、屈折率精度に優れ、更に硬度や基材との密着性に優れた硬化物を形成するのに有用なウレタン（メタ）アクリレート系化合物となることを見出し、本発明を完成した。 However, the present inventor has conducted extensive research in view of such circumstances,

In addition, by having one urethane bond on each of the left and right sides, it has low viscosity, high refractive index, excellent refractive index accuracy, and further hardness and adhesion to the substrate. It has been found that the urethane (meth) acrylate compound is useful for forming an excellent cured product, and the present invention has been completed.

That is, the gist of the present invention are those which relate to urethane (meth) acrylate compound represented by the following general formula (1).

（ここで、Ｒ_５、Ｒ_６は水素又はメチル基、Ｒ_７、Ｒ_８は炭素数１〜３の炭化水素基、Ｚは塩素、臭素、又はヨウ素、ｃは０もしくは１〜４の整数、Ｗは酸素又は硫黄である。）

(Wherein R ₅ and R ₆ are hydrogen or a methyl group, R ₇ and R ₈ are hydrocarbon groups having 1 to 3 carbon atoms, Z is chlorine, bromine, or iodine, c is an integer of 0 or 1 to 4, W is oxygen or sulfur.)

  Furthermore, the present invention relates to an active energy ray-curable composition comprising the above urethane (meth) acrylate compound and a photopolymerization initiator, and further, a coating agent or a lens comprising such an active energy ray-curable composition. It relates to a forming agent.

Since the urethane (meth) acrylate compound of the present invention has the structure represented by the general formula (1 ), it has a low viscosity, is very easy to handle, has excellent refractive index accuracy of the compound, and more A cured product obtained using a urethane (meth) acrylate-based compound has a high refractive index and has an effect of being excellent in hardness and adhesion to a substrate.

Hereinafter, the present invention will be described in detail.
The urethane (meth) acrylate compound of the present invention has an aromatic ring, a sulfur atom, and, if necessary, a halogen atom such as chlorine, bromine and iodine in the molecular structure. These atoms and atomic groups improve the refractive index of the compound and the cured product after polymerization.

In the present invention, it is important refractive index of such a cured product, the refractive index of the cured product is good preferable is 1.56 to 1.64. If the refractive index of the cured product is too low, it will be difficult to meet the recent demand for higher refractive index of the coating layer, and if it is too large, the color dispersion tends to increase.

In addition, since the urethane (meth) acrylate compound of the present invention has (meth) acryloyl groups at both ends of the molecular structure, it is quickly cured by active energy rays such as ultraviolet rays, and a cured product having a highly crosslinked structure. Form. This fast curability is important in coating applications and needs to be sufficiently cured with a small amount of light. Amount of light necessary for curing, for example, when performing curing by ultraviolet rays, preferably 5000 mJ / cm ² or less, 2000 mJ / cm ² or less being more preferred. The lower limit of the amount of light necessary for curing is usually 100 mJ / cm ² .

  Furthermore, since the urethane (meth) acrylate compound of the present invention has a urethane bond in the molecular structure, the formed coating layer has high adhesion to a substrate such as a plastic film or glass. Further, as shown in the production method described later, since it is produced by a relatively simple reaction, oligomer bodies and impurities are extremely small, and the refractive index accuracy is excellent.

  The refractive index accuracy of the urethane (meth) acrylate compound in the present invention is preferably within ± 0.001, more preferably within ± 0.0005, and particularly preferably within ± 0.0003. If the accuracy exceeds the above range, optical design of the coat layer tends to be difficult.

Hereinafter, although the manufacturing method of the urethane (meth) acrylate type compound of this invention is demonstrated, this invention is not limited to these manufacturing methods, The thing of the chemical structure shown by the said General formula (1 ) is manufactured. It only has to be done.

The urethane (meth) acrylate compound of the present invention is obtained by reacting a compound represented by the following general formula ( 2) with an isocyanatoalkyl (meth) acrylate.

（ここで、Ｒ_７は炭素数１〜３の炭化水素基、Ｚは塩素、臭素、又はヨウ素、ｃは０もしくは１〜４の整数、Ｗは酸素又は硫黄である。）

(Here, R ₇ is a hydrocarbon group having 1 to 3 carbon atoms, Z is chlorine, bromine, or iodine, c is 0 or an integer of 1 to 4, and W is oxygen or sulfur.)

Examples of the compound represented by the above formula ( 2 ) include:
Hydroxymethylthio-p-xylylene, hydroxymethylthio-m-xylylene, hydroxymethylthio-o-xylylene, β-hydroxyethylthio-p-xylylene, β-hydroxyethylthio-m-xylylene, β-hydroxyethylthio-o-xylylene 3-hydroxypropylthio-p-xylylene, 3-hydroxypropylthio-m-xylylene, 3-hydroxypropylthio-o-xylylene, 1,4-bis [hydroxymethylthiomethyl] -monochlorobenzene, 1,4-bis [Hydroxymethylthiomethyl] -dichlorobenzene, 1,4-bis [hydroxymethylthiomethyl] -trichlorobenzene, 1,4-bis [hydroxymethylthiomethyl] -2,3,5,6-tetrachlorobenzene, 1,3-bis [Hydroxy Tylthiomethyl] -2,4,5,6-tetrachlorobenzene, 1,2-bis [hydroxymethylthiomethyl] -3,4,5,6-tetrachlorobenzene, 1,4-bis [β-hydroxyethylthiomethyl]- 2,3,5,6-tetrachlorobenzene, 1,3-bis [β-hydroxyethylthiomethyl] -2,4,5,6-tetrachlorobenzene, 1,2-bis [β-hydroxyethylthiomethyl]- 3,4,5,6-tetrachlorobenzene, 1,4-bis [3-hydroxypropylthiomethyl] -2,3,5,6-tetrachlorobenzene, 1,3-bis [3-hydroxypropylthiomethyl]- 2,4,5,6-tetrachlorobenzene, 1,2-bis [3-hydroxypropylthiomethyl] -3,4,5,6-tetrachlorobenzene, 1,4 Bis [hydroxymethylthiomethyl] -2,3,5,6-tetrabromobenzene, 1,3-bis [hydroxymethylthiomethyl] -2,4,5,6-tetrabromobenzene, 1,2-bis [hydroxymethylthio Methyl] -3,4,5,6-tetrabromobenzene, 1,4-bis [β-hydroxyethylthiomethyl] -2,3,5,6-tetrabromobenzene, 1,3-bis [β-hydroxy Ethylthiomethyl] -2,4,5,6-tetrabromobenzene, 1,2-bis [β-hydroxyethylthiomethyl] -3,4,5,6-tetrabromobenzene, 1,4-bis [3 -Hydroxypropylthiomethyl] -2,3,5,6-tetrabromobenzene, 1,3-bis [3-hydroxypropylthiomethyl] -2,4,5,6-tetrabromobenzene Diol compounds such as 1,2-bis [3-hydroxypropylthiomethyl] -3,4,5,6-tetrabromobenzene,

Mercaptomethylthio-p-xylylene, mercaptomethylthio-m-xylylene, mercaptomethylthio-o-xylylene, β-mercaptoethylthio-p-xylylene, β-mercaptoethylthio-m-xylylene, β-mercaptoethylthio-o-xylylene , 3-mercaptopropylthio-p-xylylene, 3-mercaptopropylthio-m-xylylene, 3-mercaptopropylthio-o-xylylene, 1,4-bis [mercaptomethylthiomethyl] -monochlorobenzene, 1,4-bis [Mercaptomethylthiomethyl] -dichlorobenzene, 1,4-bis [mercaptomethylthiomethyl] -trichlorobenzene, 1,4-bis [mercaptomethylthiomethyl] -2,3,5,6-tetrachlorobenzene, 1,3-bis [Mercapto Tylthiomethyl] -2,4,5,6-tetrachlorobenzene, 1,2-bis [mercaptomethylthiomethyl] -3,4,5,6-tetrachlorobenzene, 1,4-bis [β-mercaptoethylthiomethyl]- 2,3,5,6-tetrachlorobenzene, 1,3-bis [β-mercaptoethylthiomethyl] -2,4,5,6-tetrachlorobenzene, 1,2-bis [β-mercaptoethylthiomethyl]- 3,4,5,6-tetrachlorobenzene, 1,4-bis [3-mercaptopropylthiomethyl] -2,3,5,6-tetrachlorobenzene, 1,3-bis [3-mercaptopropylthiomethyl]- 2,4,5,6-tetrachlorobenzene, 1,2-bis [3-mercaptopropylthiomethyl] -3,4,5,6-tetrachlorobenzene, 1,4 Bis [mercaptomethylthiomethyl] -2,3,5,6-tetrabromobenzene, 1,3-bis [mercaptomethylthiomethyl] -2,4,5,6-tetrabromobenzene, 1,2-bis [mercaptomethylthio] Methyl] -3,4,5,6-tetrabromobenzene, 1,4-bis [β-mercaptoethylthiomethyl] -2,3,5,6-tetrabromobenzene, 1,3-bis [β-mercapto Ethylthiomethyl] -2,4,5,6-tetrabromobenzene, 1,2-bis [β-mercaptoethylthiomethyl] -3,4,5,6-tetrabromobenzene, 1,4-bis [3 -Mercaptopropylthiomethyl] -2,3,5,6-tetrabromobenzene, 1,3-bis [3-mercaptopropylthiomethyl] -2,4,5,6-tetrabromobenzene And dithiol compounds such as 1,2-bis [3-mercaptopropylthiomethyl] -3,4,5,6-tetrabromobenzene.

Among these, a diol compound is preferable from the viewpoint of odor, a non-halogen compound is more preferable from an environmental viewpoint, and particularly preferably, from the viewpoint of the viscosity of the resulting urethane (meth) acrylate compound, the following formula ( 3 ) Β-hydroxyethylthio-p-xylylene having a chemical structure.

  Specific examples of the isocyanatoalkyl (meth) acrylate include, for example, isocyanatomethyl (meth) acrylate, 2-isocyanatoethyl (meth) acrylate, 2-isocyanatopropyl (meth) acrylate, 3-isocyanatopropyl (meth) ) Aliphatic isocyanatoalkyl (meth) acrylates such as acrylate.

  Among these, 2-isocyanatoethyl (meth) acrylate is preferable from the viewpoint of availability, and 2-isocyanatoethyl acrylate is particularly preferable from the viewpoint of quick curing of the obtained urethane (meth) acrylate compound. .

2 with a compound represented by the above formula (2), charging ratio is in the reaction of isocyanatoalkyl (meth) acrylate, relative to 1 mole of the compound represented by the above formula (2), isocyanatoethyl (meth) acrylate It is preferably 2.1 mol. If the amount is too small, the hydroxyl-terminated or mercapto-group-terminated compound remains in the reaction system after the reaction, so that the desired urethane (meth) acrylate compound tends to be not obtained in a good yield. Since the raw material isocyanatoalkyl (meth) acrylate remains in the reaction system later, the target urethane (meth) acrylate compound tends not to be obtained in good yield.

In the present invention, a reaction method in which the compound represented by the above formula ( 2) is dissolved in an organic solvent and this solution is dropped into an isocyanatoalkyl (meth) acrylate is preferable. Examples of the organic solvent used include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, aliphatic alcohols such as n-propyl alcohol and iso-propyl alcohol, acetone, and methyl ethyl ketone. And ketones such as cyclohexanone and ethers such as tetrahydrofuran and diethyl ether. Of these, tetrahydrofuran is particularly preferred from the viewpoint of solubility.

The concentration of the compound represented by the above formula ( 2) in the solution is preferably 1 to 500 parts by weight / L, more preferably 10 to 300 parts by weight / L, and still more preferably 50 to 200 parts by weight / L. The preferable range of the dropping rate is preferably 1 to 100 mol / hour, more preferably 5 to 100 mol / hour, still more preferably 10 to 100 when the total amount of the compound represented by the above formula ( 2) is 100 mol. Mol / hour. If the dropping speed is too slow, the productivity tends to be inferior, and if it is too fast, the reaction runs away, and the isocyanatoalkyl (meth) acrylate as a raw material tends to be polymerized due to the heat generation.

In the present invention, it is preferable to use a metal catalyst such as dibutyltin dilaurate or an amine catalyst such as 1,8-diazabicyclo [5.4.0] undecene-7 for the purpose of promoting the reaction. The amount of the catalyst added is preferably 0.01 parts by weight or more, particularly 0.01 to 0.1 parts by weight, and more preferably 0.000 parts by weight with respect to 100 parts by weight of the compound represented by the above formula ( 2) . It is preferable that it is 02-0.05 weight part. If the amount added is too small, the productivity tends to be inferior.

  The reaction temperature is usually in the range of 40 to 80 ° C, preferably 50 to 70 ° C, more preferably 55 to 65 ° C. If the reaction temperature is too low, the productivity tends to be inferior. If the reaction temperature is too high, the raw material isocyanatoalkyl (meth) acrylate tends to be polymerized.

The reaction is preferably performed under an inert gas in order to improve the hue of the product.
The end point of the reaction can be judged by confirming the amount of isocyanate in the reaction solution by a technique such as titration. Examples of the titration method include collecting a part of the reaction product, adding it to di-n-butylamine, causing the reaction, and back titrating the remaining di-n-butylamine with hydrochloric acid.

The obtained urethane (meth) acrylate-based compound may be washed to remove a trace amount of raw material isocyanatoalkyl (meth) acrylate and the like. As a washing method, a poor solvent of the compound of the general formula (1 ) is introduced into the reaction system, and isocyanatoalkyl (meth) acrylate transferred to the poor solvent layer is removed. As the poor solvent, lower alcohols such as methanol and ethanol, and mixed solvents thereof are preferable.
Thus, the urethane (meth) acrylate compound of the present invention is obtained.

  Next, the active energy ray-curable composition using the urethane (meth) acrylate compound of the present invention will be described.

The active energy ray curable composition of the present invention is obtained by containing urethane (meth) acrylate compound represented by the general formula (1) and (A) a photopolymerization initiator (B), a high refractive It becomes an active energy ray-curable composition suitable as a rate coating agent or a lens forming agent.

  The photopolymerization initiator (B) 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-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio ) Phenyl] -2-morpholinopropane-1, benzoin, benzoin methyl ether, benzene Inethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldimethyl ketal, 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, acylphos Examples include fin oxide, methylphenylglyoxylate, benzyl, 9,10-phenanthrenequinone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, among which benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one are preferred. Used for.

  The content of the photopolymerization initiator (B) is preferably 0.1 to 10 parts by weight, more preferably 1 to 8 parts by weight, based on 100 parts by weight of the urethane (meth) acrylate compound (A). Particularly preferred is 2 to 5 parts by weight. If the content is too small, the curing rate tends to be slow, and if it is too large, the hue of a cured product such as a coat layer tends to deteriorate.

  Further, as an auxiliary of the photopolymerization initiator (B), for example, triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid Acid, ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-Diisopropylthioxanthone or the like can be used in combination.

  Moreover, in this invention, in addition to a photoinitiator (B), it is also possible to contain a mercaptan compound as a chain transfer agent.

  As the mercaptan compound, a compound having a plurality of thiol groups in the molecular structure is preferable. By using a compound having a plurality of thiol groups, it is possible to further increase the refractive index and improve the surface hardness.

  Examples of mercaptan compounds having a plurality of thiol groups include benzenedithiol, xylylenedithiol, hexanedithiol, tolylenetrithiol, pentaerythritol tetrakis (β-thiopropionate), pentaerythritol tetrakis (thioglycolate), tri Methylolpropane tris (β-thiopropionate), trimethylolpropane tris (thioglycolate), diethylene glycol bis (β-thiopropionate), diethylene glycol bis (thioglycolate), triethylene glycol bis (β-thiopro) Pionate), triethylene glycol bis (thioglycolate), dipentaerythritol hexakis (β-thiopropionate), dipentaerythritol hexakis (thioglycolate) ), Tris [2- (β-thiopropionyloxy) ethyl] triisocyanurate, tris (2-thioglyconyloxyethyl) triisocyanurate, tris [2- (β-thiopropionyloxyethoxy) ethyl] triisocyanurate , Tris (2-thioglyconyloxyethoxyethyl) triisocyanurate, tris [3- (β-thiopropionyloxy) propyl] triisocyanurate, tris (3-thioglyconyloxypropyl) triisocyanurate, and the like. .

  In addition, the active energy ray-curable composition of the present invention may use other copolymerizable components and various additives as necessary.

  As another copolymerization component, for example, an ethylenically unsaturated monomer is preferable. The ethylenically unsaturated monomer may be any monomer having one or more ethylenically unsaturated groups in one molecule, and examples thereof include monofunctional monomers, bifunctional monomers, and trifunctional or more monomers.

  Examples of the monofunctional monomer include styrene, vinyl toluene, chlorostyrene, α-methyl styrene, methyl (meth) acrylate, ethyl (meth) acrylate, acrylonitrile, vinyl acetate, 2-hydroxyethyl (meth) acrylate, and 2-hydroxy. Propyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3- Chloro-2-hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate, glycidyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, isoborni (Meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl ( (Meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylate, benzyl (meth) acrylate, phenol ethylene oxide modified (meth) acrylate, nonylphenol propylene oxide modified ( Half ester (meth) acrylates of phthalic acid derivatives such as (meth) acrylate and 2- (meth) acryloyloxy-2-hydroxypropyl phthalate, furfuryl (meth) acrylate Relate, carbitol (meth) acrylate, benzyl (meth) acrylate, butoxyethyl (meth) acrylate, allyl (meth) acrylate, acryloylmorpholine, 2-hydroxyethylacrylamide, N-methylol (meth) acrylamide, N-vinylpyrrolidone , 2-vinylpyridine, 2- (meth) acryloyloxyethyl acid phosphate monoester, and the like.

  In addition to the above, as a monofunctional monomer, there may also be mentioned a Michael adduct of acrylic acid or 2-acryloyloxyethyl dicarboxylic acid monoester. Examples of the Michael adduct of acrylic acid include acrylic acid dimer, methacrylic acid dimer, acrylic acid. Examples include trimers, methacrylic acid trimers, acrylic acid tetramers, and methacrylic acid tetramers. Examples of 2-acryloyloxyethyl dicarboxylic acid monoester which is a carboxylic acid having a specific substituent include 2-acryloyloxyethyl succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, and 2-acryloyloxyethyl. Examples include phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahydrophthalic acid monoester, and 2-methacryloyloxyethyl hexahydrophthalic acid monoester. Furthermore, oligoester acrylate is also mentioned.

  Examples of the bifunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and dipropylene. Glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type Di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,6-hexanediol ethylene oxide modified di ( Acrylate), glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, diglycidyl phthalate di (meth) acrylate Hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide-modified diacrylate, 2- (meth) acryloyloxyethyl acid phosphate diester, and the like.

Examples of the tri- or higher functional monomer include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth). ) Acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified triacrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol Hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, Chi alkylene oxide modified pentaerythritol tetra (meth) acrylate, and succinic acid-modified pentaerythritol tri (meth) acrylate.
Said ethylenically unsaturated monomer may be used independently and may use 2 or more types together.

  Although content of the said ethylenically unsaturated monomer is not specifically limited, 50 weight part or less is preferable with respect to 100 weight part of urethane (meth) acrylate type compounds (A), and 30 weight part or less is more preferable. If the amount is too large, the refractive index tends to decrease.

  Various additives include silane coupling agents, antioxidants, polymerization inhibitors, yellowing inhibitors, ultraviolet absorbers, fillers, dyes and pigments, oils, plasticizers, waxes, desiccants, dispersants, wetting agents. Agents, emulsifiers, gelling agents, stabilizers, antifoaming agents, leveling agents, thixotropy imparting agents, flame retardants, fillers, reinforcing agents, matting agents, crosslinking agents and the like.

  Thus, the active energy ray-curable composition of the present invention is suitably used as a coating agent for forming a coating layer having a low viscosity and high refractive index, refractive index accuracy, coating film hardness and excellent adhesion to a substrate. used.

  When used as a coating agent, the coating method is not particularly limited, and known methods such as spin coating, dip coating, bar coating, and gravure coating are used.

  When adjusting the coating agent, the composition is diluted with a solvent as necessary. Examples of the solvent include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate, butyl acetate and propylene glycol monomethyl ether acetate, aliphatic alcohols such as n-propyl alcohol and iso-propyl alcohol, acetone And known organic solvents such as ketones such as methyl ethyl ketone and cyclohexanone.

  The amount of the organic solvent is preferably 1 to 100 parts by weight, more preferably 5 to 90 parts by weight, and still more preferably 10 to 80 parts by weight with respect to 1 part by weight of the urethane (meth) acrylate compound. If the amount is too small, the viscosity becomes high and the coating property tends to be poor. If the amount is too large, the drying load tends to increase.

  The coating agent of the present invention is cured by irradiating an active energy ray after coating this on a substrate and drying the solvent as necessary. Such a base material is not particularly limited. For example, polyolefin resin such as polyethylene, polypropylene, polycyclopentadiene, polycarbonate, polyester, ABS resin, acrylic resin and the like (film, sheet, lens, etc.). , Glass, metal and the like.

  As such active energy rays, rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X rays and γ rays, electron beams, proton rays, neutron rays, etc. can be used. Curing by ultraviolet irradiation is advantageous from the viewpoint of easy availability and price. In addition, when performing electron beam irradiation, it can harden | cure even if it does not use a photoinitiator.

As a method of curing by ultraviolet irradiation, about 100 to 5000 mJ / cm ² using a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, etc. It is sufficient to irradiate the ultraviolet rays. After the ultraviolet irradiation, heating can be performed as necessary to complete the curing.

  Thus, the active energy ray-curable composition of the present invention has a low viscosity, a high refractive index, an excellent refractive index accuracy, and further a curing of a coating layer having excellent hardness and adhesion to a substrate. It is useful as various film forming materials such as paints, pressure-sensitive adhesives, adhesives, inks, protective coating agents, anchor coating agents, and coating binders. Among them, it is very useful for use as a coating agent for display substrates, optical films, lenses, solar cells, memory disks, and the like.

  The active energy ray-curable composition of the present invention is also suitably used as a lens forming agent for forming microlenses such as Fresnel lenses and microlens arrays on a substrate.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In the examples, “parts” and “%” mean weight basis unless otherwise specified.

Example 1
[Synthesis 1 of urethane (meth) acrylate compound (A) (A1-1)]
A four-necked flask equipped with a dropping funnel, thermometer, stirrer, water-cooled condenser and nitrogen gas inlet is charged with 52.2 g (0.37 mol) of 2-isocyanatoethyl acrylate and 0.02 g of dibutyltin dilaurate, In the dropping funnel, a uniform solution of 46.5 g (0.18 mol) of β-hydroxyethylthio-p-xylylene and 700 g of THF was charged. After raising the temperature in the flask to 60 ° C., the solution was dropped from the dropping funnel at a rate of 370 g / hour to carry out the reaction, and the reaction was terminated when the residual isocyanate group reached 0.1%. Thereafter, 0.4 g of hydroquinone methyl ether was added as a polymerization inhibitor, and the solvent was distilled off to obtain a urethane (meth) acrylate compound (A1-1).

Of the obtained urethane (meth) acrylate compound (A1-1) ¹³ C-NMR (reference material: tetramethylsilane, solvent: CDCl ₃ ), ¹ H-NMR (reference material: tetramethylsilane, solvent: CDCl ₃ ) And infrared spectrum, the structure of this urethane (meth) acrylate compound (A1-1) was as follows.

NMR was measured using “UNITY 300” manufactured by VARIAN, and infrared was measured using “AVATAR 360” manufactured by NICOLET .

[Synthesis 2 (A1-2) and Synthesis 3 (A1-3) of urethane (meth) acrylate compound (A)]
The urethane (meth) acrylate compound (A) was synthesized repeatedly by the production method described above to obtain urethane (meth) acrylate compounds (A1-2) and (A1-3).

  The urethane (meth) acrylate compounds (A1-1), (A1-2), and (A1-3) obtained above were evaluated as follows.

(Refractive index of compound)
The refractive index of the obtained urethane (meth) acrylate-based compounds (A1-1), (A1-2), and (A1-3) is changed to “Abbe refractometer 1T (NaD line, 23 ° C.)” manufactured by Atago Co., Ltd. As shown in Table 1, they were 1.5321 , 1.5323 , and 1.5325 , respectively. The accuracy of the refractive index was within ± 0.001 , and the refractive index accuracy was good.

(Preparation of active energy ray-curable composition)
To 100 parts of each of the urethane (meth) acrylate compounds (A1-1), (A1-2), and (A1-3) obtained above, 2-hydroxy-2-methyl as a photopolymerization initiator (B) 2 parts of -1-phenyl-propan-1-one (Ciba Specialty Chemicals, “Darocur 1173”) was added to the active energy ray-curable composition (A1-10), (A1-20), ( A1-30) was obtained.

[Coating agent adjustment]
102 parts of each of the active energy ray-curable resin compositions (A1-10), (A1-20), and (A1-30) are dissolved in 1000 parts of ethyl acetate, and coating agents (A1-100), ( A1-200) and (A1-300) were adjusted.

[Formation of coat layer]
Each of the coating agents (A1-100), (A1-200) and (A1-300) obtained above was spin-coated on a PET film having a thickness of 100 μm (part of the plate surface for film thickness measurement). And masked with tape. After drying at 80 ° C. for 10 minutes, using one high pressure mercury lamp 80W, one pass of UV irradiation (cumulative dose 1000 mJ / cm ² ) is performed at a conveyor speed of 4.3 m / min from a height of 13 cm. The coating layers (K1-1), (K1-2), and (K1-3) having a thickness of 1 μm were formed. The following three coating layers were evaluated. The evaluation results are shown in Table 2.

(Refractive index of coat layer)
The refractive index of the coat layer was measured using an “Abbe refractometer 1T (NaD line, 23 ° C.)” manufactured by Atago Co., Ltd.

(surface hardness)
The pencil hardness was measured according to JIS K 5600-5-4.

(Adhesion)
A peel test (peeling speed 10 cm / sec) was performed according to JIS K 5600-5-6. The case where the coating layer was peeled off from the PET base material was indicated as x, and the case where the coating layer was not peeled off was indicated as ◯.

Comparative Example 1
A four-necked flask equipped with a dropping funnel, thermometer, stirrer, water-cooled condenser and nitrogen gas blowing port was charged with 69.0 g (0.37 mol) of m-xylene diisocyanate and 0.02 g of dibutyltin dilaurate, while dropping. The funnel was charged with a uniform solution of 67.9 g (0.18 mol) of 4,4′-bis [β-hydroxyethylthio] diphenylsulfone and 700 g of tetrahydrofuran. After the temperature in the flask was raised to 60 ° C., the reaction was carried out by dropping the solution at 380 g / hour from the dropping funnel, and the reaction was terminated when the residual isocyanate group reached 1.8%. Subsequently, 163.2 g (0.37 mol) of pentaerythritol triacrylate (“Kyoeisha Chemical Industry Co., Ltd.“ Light acrylate PE-3A ”) and 0.4 g of hydroquinone methyl ether were added to the reaction system at 50 ° C., and then at 60 ° C. The reaction was terminated for 5 hours, and the reaction was terminated when the residual isocyanate group reached 0.1%. After the reaction liquid was concentrated, 500 g of methyl isobutyl ketone was added for washing, and the washing liquid was discarded. Subsequently, 500 g of toluene was added and stirred for 1 hour, followed by filtration using activated clay. Thereafter, the solvent was distilled off to produce a urethane (meth) acrylate compound (A ′). The production was repeated three times to obtain urethane (meth) acrylate compounds (A′-1), (A′-2) and (A′-3).
With respect to the urethane (meth) acrylate compounds (A′-1), (A′-2) and (A′-3), the refractive index was measured in the same manner as in Example 1. They were 1.5492, 1.5501, and 1.5513, and the refractive index accuracy was inferior.
Furthermore, an active energy ray-curable composition and a coating agent were prepared in the same manner as in Example 1, and the coating layers (K′-1), (K′-2), and (K′-3) was formed. Table 2 shows the evaluation results of the obtained three coating layers. The accuracy of the refractive index of the coat layer was poor.

Comparative Example 2
In Example 1, instead of the urethane (meth) acrylate compound (A) , except that 100 parts of 4,4′-bis [β-acryloyloxyethylthio] diphenylsulfone was used, the same as in Example 1, A (meth) acrylate compound (A ″), an active energy ray-curable resin composition, and a coating agent were prepared, and a coating layer (K ″ -1) was formed in the same manner as in Example 1. Table 2 shows the evaluation results of the obtained coating layer (K ″ -1).

  The urethane (meth) acrylate-based compound of the present invention and the active energy ray-curable composition comprising the same have a low viscosity, a high refractive index, excellent refractive index accuracy, hardness, It can form cured products such as coating layers with excellent adhesion to materials, and is useful as various film forming materials such as paints, adhesives, adhesives, inks, protective coating agents, anchor coating agents, and coating binders. Among them, it is very useful for use as a coating agent for display substrates, optical films, lenses, solar cells, memory disks, and the like. Further, it is also suitably used as a lens forming agent for forming microlenses such as Fresnel lenses and microlens arrays on a substrate.

Claims (6)

A urethane (meth) acrylate compound represented by the following general formula ( 1 ).

(Wherein R ₅ and R ₆ are hydrogen or a methyl group, R ₇ and R ₈ are hydrocarbon groups having 1 to 3 carbon atoms, Z is chlorine, bromine, or iodine, c is an integer of 0 or 1 to 4, W is oxygen or sulfur.) Claim 1 Symbol placement urethane (meth) acrylate compound refractive index is characterized by a 1.56 to 1.64 of the cured product. The urethane (meth) acrylate compound according to claim 1 or 2 , wherein the accuracy of the refractive index of the compound is within ± 0.001. An active energy ray-curable composition comprising the urethane (meth) acrylate compound (A) according to any one of claims 1 to 3 and a photopolymerization initiator (B). A coating agent comprising the active energy ray-curable composition according to claim 4 . A lens forming agent comprising the active energy ray-curable composition according to claim 4 .