JP6965186B2 - Photocurable resin composition - Google Patents

Description

The present invention relates to a photocurable resin composition. More specifically, the present invention relates to a photocurable resin composition that provides a cured product having excellent scratch resistance and high pencil hardness and transparency.

In recent years, display devices such as liquid crystal displays and touch panel displays provided with a film having a hard coat film as a protective layer on the surface have rapidly become widespread. In particular, electronic devices such as smartphones and tablet terminals equipped with a touch panel that can be operated by directly touching the screen with a finger or a pen have become widespread, and such devices are required to improve the hardness of the touch panel surface.
As the material of the touch panel, it is desirable to use a resin such as PET or acrylic which is safer and lighter than glass, but these resins have a drawback of being inferior in hardness to glass.

For this reason, a method of forming a hard coat layer containing an active energy ray-curable resin containing highly hard silica fine particles as a filler as a main component is known, but silica fine particles, which are inorganic substances, are organic substances, which are active energy ray-curable substances. Since it is difficult to disperse uniformly in the monomer of the resin, a method of improving the dispersibility by organically treating the surface of the silica fine particles has been performed (see, for example, Patent Documents 1 to 3).
However, the ultraviolet curable resin composition produced by this method has a problem that the content of silica particles is limited from the viewpoint of transparency of the cured product, and a desired film hardness cannot be obtained.

Japanese Unexamined Patent Publication No. 2000-264621 JP-A-2015-86103 JP-A-2015-36402

An object of the present invention is to provide a photocurable resin composition which has excellent scratch resistance, high hardness, and gives a cured product having excellent transparency.

The present inventors have arrived at the present invention as a result of studies for achieving the above object.
That is, the present invention is a polyfunctional urethane (meth) acrylate (B) having a condensate (A) of a metal alkoxide (a) represented by the following general formula (1) and 6 to 15 (meth) acryloyl groups. A photocurable resin composition containing a polyfunctional (meth) acrylate (C) other than (B) and a photopolymerization initiator (D).

[In the formula (1), R ¹ and R ² are independent ester compounds having one or more hydroxyl groups of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a polyhydric alcohol, and (meth) acrylic acid (meth). Represents a residue obtained by removing one hydroxyl group from d), and R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and one or more of a polyhydric alcohol and (meth) acrylic acid. Represents a residue obtained by removing one hydroxyl group from the ester compound (d) having a hydroxyl group of, or a metal atom-containing group represented by the following general formula (2), and a plurality of R ³ and R ⁴ are the same, respectively. M may represent a silicon atom, a titanium atom or a zirconium atom, and a plurality of M may be the same or different, and n is an integer of 2 to 15. ]

[In formula (2), R ⁵ , R ⁶ and R ⁷ are esters having one or more hydroxyl groups of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a polyhydric alcohol and (meth) acrylic acid, respectively. Represents a residue obtained by removing one hydroxyl group from compound (d), and when there are a plurality of R ⁵ and R ⁶ , they may be the same or different, and M represents a silicon atom, a titanium atom, or a zirconium atom. Represented, a plurality of Ms may be the same or different, and k is an integer of 1 to 5. ]

The photocurable resin composition of the present invention has an effect of being able to give a cured product having excellent scratch resistance and high hardness and transparency.

The photocurable resin composition of the present invention is other than the condensate (A) of the metal alkoxide (a) and the polyfunctional urethane (meth) acrylate (B) and (B) having 6 to 15 (meth) acryloyl groups. It contains a polyfunctional (meth) acrylate (C) and a photopolymerization initiator (D).
In the present invention, "(meth) acrylate" means "acrylate or methacrylate", "(meth) acrylic acid" means "acrylic acid or methacrylic acid", and "(meth) acryloyl group" means "acryloyl". It means "group or methacryloyl group".

The following are polyfunctional urethane (meth) acrylates (B) having 6 to 15 (meth) acryloyl groups, a condensate of the essential component metal alkoxide (a), and polyfunctional (meth) other than (B). The acrylate (C) and the photopolymerization initiator (D) will be described in order.

The condensate (A) of the metal alkoxide (a) in the present invention is represented by the following general formula (1).

^{R 1} and R ² in the general formula (1) are ester compounds having one or more hydroxyl groups of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a polyhydric alcohol, and (meth) acrylic acid, respectively. Represents a residue obtained by removing one hydroxyl group from d).

Here, the ester compound (d) having one or more hydroxyl groups of the polyhydric alcohol and (meth) acrylic acid is a hydroxyl group among the ester reaction products obtained by reacting the polyhydric alcohol with acrylic acid or methacrylic acid. Means that at least one ester compound remains, and the residue obtained by removing one hydroxyl group from this ester compound is used as ^{R 1} and / or R ^2.

As the polyhydric alcohol, a general polyhydric alcohol in which the hydrogen atom of a hydrocarbon such as ethylene glycol, 1,4-butylene glycol, glycerin, trimethylolpropane and pentaerythritol is substituted with a hydroxyl group; as a derivative thereof. Examples thereof include diethylene glycol, triethylene glycol, dipentaerythritol and tripentaerythritol.

Examples of the ester compound (d) having one or more hydroxyl groups of the polyhydric alcohol and the (meth) acrylic acid include ethylene glycol mono (meth) acrylate, butylene glycol mono (meth) acrylate, glycerin mono (meth) acrylate, and glycerin. Di (meth) acrylate, trimethylolpropane mono (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol mono (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipenta Examples thereof include erythritol tetra (meth) acrylate, dipenta erythritol penta (meth) acrylate and tripenta erythritol hepta (meth) acrylate.
Of these, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate and tripentaerythritol hepta (meth) acrylate are preferable from the viewpoint of hardness.

^{R 3} and R ⁴ in the general formula (1) are ester compounds (d) each independently having a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and one or more hydroxyl groups of a polyhydric alcohol and (meth) acrylic acid. ) With one hydroxyl group removed or a metal atom-containing group represented by the following general formula (2), and a plurality of R ³ and R ⁴ may be the same or different, respectively.

^{R 5} , R ⁶ and R ⁷ in the general formula (2) are esters having one or more hydroxyl groups of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a polyhydric alcohol and (meth) acrylic acid, respectively. It represents a residue obtained by removing one hydroxyl group from compound (d), and when there are a plurality of residues, R ⁵ and R ⁶ may be the same or different.
M in the general formula (1) and the general (2) represents a silicon atom, a titanium atom or a zirconium atom, and from the viewpoint of hardness, a silicon atom and a titanium atom are preferable. The plurality of Ms in the general formula (1) and the general formula (2) may be the same or different.
K in the general formula (2) is an integer of 1 to 5, and is preferably 1 from the viewpoint of hardness.

N in the general formula (1) is an integer of 2 to 15, and is preferably 2 to 10 from the viewpoint of hardness and transparency.

^{From the viewpoint of hardness, at least one of R 1 to} R ⁴ in the general formula (1) ^{and R 5 to} R ⁷ in the general formula (2) is one or more of a polyhydric alcohol and (meth) alkoxide. It is a residue obtained by removing one hydroxyl group from the ester compound (d) having a hydroxyl group, and the condensate (A) of the metal alkoxide (a) represented by the general formula (1) is a polyhydric alcohol and (meth) acrylic. It is preferable to have at least one residue obtained by removing one hydroxyl group from the ester compound (d) having one or more hydroxyl groups with the acid.

Further, from the same viewpoint, the residue obtained by removing one hydroxyl group from the ester compound (d) having one or more hydroxyl groups of the polyhydric alcohol and (meth) acrylic acid is represented by the following general formula (3). It is preferably an organic group to be produced.

In the general formula (3), m is an integer of 0 to 5, and when m is 0, the residue of pentaerythritol triacrylate, when m is 1, the residue of dipentaerythritol pentaacrylate, and m is 2. If m is 3, the residue of tripentaerythritol heptaacrylate, if m is 3, tetrapentaerythritol nonane acrylate, if m is 4, the residue of pentapentaerythritol undecane acrylate, if m is 5, hexapentaerythritol tridecane acrylate. Residue.
From the viewpoint of hardness and coatability, m is preferably 0 to 3.

The condensate (A) of the metal alkoxide (a) of the present invention is obtained by condensing a hydrolyzate of the metal alkoxide (a) such as tetraalcoxylan and water.
By allowing the ester compound (d) having one or more hydroxyl groups of the polyhydric alcohol and (meth) acrylic acid to coexist during this condensation reaction, at least one ^{of R 1 to} R ^{4 of the general formula (1) is allowed to coexist. Alternatively, at least one of R 5 to} R ⁷ of the general formula (2) is a residue obtained by removing the hydroxyl group from the ester compound (d) having one or more hydroxyl groups of the polyhydric alcohol and (meth) acrylic acid. Then, a residue obtained by removing the hydroxyl group from the ester compound (d) having one or more hydroxyl groups of the polyhydric alcohol and (meth) acrylic acid is introduced into the condensate (A), and the hardness is remarkably improved.

Examples of the metal alkoxide (a) include alkoxysilane, alkoxytitanium, and alkoxyzirconium.
Of these, alkoxysilane and alkoxyzirconium are preferable from the viewpoint of hardness.

Examples of the alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane and tetrabutoxysilane, and examples of these commercially available products include tetraethoxysilane (manufactured by Tokyo Kasei Kogyo Co., Ltd.), ethyl silicate 28, and ethyl silicate 28P. , N-propyl silicate, N-butyl silicate (above, manufactured by Corcote Co., Ltd.), methyl orthosilicate, ethyl orthosilicate, high-purity ethyl orthosilicate, high-purity ethyl orthosilicate (EL) (above, manufactured by Tama Chemical Industry Co., Ltd.) ) And Dynasilan SILBOND CONDENSED (manufactured by Ebonic Japan Co., Ltd.) and the like.
Examples of the alkoxyzirconium include tetraethoxyzirconium and tetrabutoxyzirconium, and examples of these commercially available products include tetrabutoxyzirconium (TBZR) (manufactured by Nippon Soda Corporation).
As the condensate (A), one type may be used alone or two or more types may be used in combination.

The temperature at which the condensate (A) of the metal alkoxide (a) is produced is preferably 40 to 80 ° C, more preferably 60 to 70 ° C. When the temperature is 40 ° C. or higher, the reaction rate becomes high, so that the productivity is improved. Further, when the temperature is 80 ° C. or lower, the hydrolysis and polycondensation of the metal alkoxide (a) can proceed without the polyfunctional (meth) acrylate being polymerized and polymerized in the reaction system. Further, under these conditions, the reaction of the metal alkoxide (a) hydrolyzate, the polyhydric alcohol, and the ester compound (d) having one or more hydroxyl groups with (meth) acrylic acid also proceeds sufficiently.

The reaction time for producing the condensate (A) of the metal alkoxide (a) is preferably 30 minutes to 6 hours, more preferably 2 hours to 4 hours.

The photocurable resin composition of the present invention can obtain a cured product having high hardness by containing the condensate (A), but generally contains an inorganic substance such as the condensate (A) in order to increase the hardness. Increasing the amount tends to impair transparency.
Therefore, when the condensate (A) is produced, the metal alkoxide (a) is reacted with water in a polyfunctional (meth) acrylate (C) other than (B) described later to condense the metal alkoxide (a). It is preferable to obtain the product (A). Since the condensate (A) thus obtained is produced by reacting in a polyfunctional (meth) acrylate (C), it has excellent compatibility with (C) and is excellent in compatibility with the condensate (A). Even if the content of is high, a cured product having excellent transparency and high hardness can be obtained.

The polyfunctional urethane (meth) acrylate (B) having 6 to 15 (meth) acryloyl groups as an essential component of the photocurable resin composition of the present invention has 6 to 15 (meth) acryloyl groups. The (meth) acrylate having a urethane bond in the molecule is not particularly limited, but the bifunctional or trifunctional polyisocyanate compound (b), 3 to 5 (meth) acryloyl groups, and at least 1 hydroxyl group. It is preferably a urethane (meth) acrylate obtained by a urethanization reaction with the (meth) acrylate (c) having.

Examples of the bifunctional or trifunctional polyisocyanate (b) include aliphatic polyisocyanates [hexamethylene diisocyanate and the like], aromatic (lipid) group polyisocyanates [2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, etc.]. 1,5-Naphthalene diisocyanate, xylylene diisocyanate, etc.], alicyclic polyisocyanate [isophorone diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), etc.], and these nurate compounds, biuret compounds, and allophanate compounds can be mentioned.

Examples of the (meth) acrylate (c) having 3 to 5 (meth) acryloyl groups and at least one hydroxyl group include pentaerythritol tri (meth) acrylate and dipentaerythritol hexa (meth) acrylate.
The polyfunctional urethane (meth) acrylate (B) may be used alone or in combination of two or more.

The number of functional groups of the polyfunctional (meth) acrylate (C) other than (B), which is an essential component of the photocurable resin composition of the present invention, is not particularly limited, but from the viewpoint of hardness, at least two, preferably three. It is preferably a polyfunctional (meth) acrylate having ~ 6 (meth) acryloyl groups.

Specific examples of the polyfunctional (meth) acrylate (C) other than (B) include di (meth) acrylate (C1), trivalent or higher (meth) acrylate (C2), and polyester (meth) acrylate (C3). ), Urethane (meth) acrylate (C4) having 2 to 4 (meth) acryloyl groups, epoxy (meth) acrylate (C5), (meth) acryloyl group-modified butadiene polymer (C6), (meth) acryloyl group-modified Examples thereof include a dimethylpolysiloxane polymer (C7).

The di (meth) acrylate (C1) is a di (meth) acrylate of a polyoxyalkylene glycol and a di (meth) adduct of an alkylene oxide of a divalent phenol compound (hereinafter, “alkylene oxide” is abbreviated as AO). Examples thereof include acrylates, di (meth) acrylates of linear or branched aliphatic dihydric alcohols having 2 to 30 carbon atoms, and di (meth) acrylates of alicyclic divalent alcohols having 6 to 30 carbon atoms.

As the di (meth) acrylate of polyoxyalkylene glycol, polyoxyalkylene glycol (alkylene has 2 to 4 carbon atoms) [chemical formula amount of 106 or more and number average molecular weight {number average by gel permeation chromatography (GPC) method). Molecular weight: Hereinafter abbreviated as Mn. } 3,000 or less] di (meth) acrylates [polyethylene glycol (Mn400), polypropylene glycol (Mn200), polytetramethylene glycol (Mn650) di (meth) acrylates, etc.] and the like can be mentioned.

As the di (meth) acrylate of the AO adduct of the dihydric phenol compound, the di (meth) acrylate of the AO (2 to 30 mol) adduct of the divalent phenol compound, for example, the divalent phenol compound [monocyclic phenol (catechol) , Resolsinol, hydroquinone, etc.), condensed polycyclic phenol (dihydroxynaphthalene, etc.) and bisphenol compounds (bisphenol A, bisphenol F, bisphenol S, etc.)] AO adduct [resorcinol ethylene oxide (hereinafter abbreviated as "EO"). ) Di (meth) acrylate of 4 mol adduct, propylene oxide of dihydroxynaphthalene (hereinafter abbreviated as "PO") EO2 mol of di (meth) acrylate, bisphenol A, bisphenol F or bisphenol S of 4 mol adduct Or each additive of PO4 mol] and the like.

Examples of the di (meth) acrylate of a linear or branched aliphatic dihydric alcohol having 2 to 30 carbon atoms include neopentyl glycol and 1,6-hexanediol di (meth) acrylates.

Examples of the di (meth) acrylate of the alicyclic dihydric alcohol having 6 to 30 carbon atoms include di (meth) acrylate of dimethyloltricyclodecane, di (meth) acrylate of cyclohexanedimethanol, and di (meth) acrylate of hydrogenated bisphenol A. Meta) acrylate and the like can be mentioned.

Examples of the trivalent or higher (meth) acrylate (C2) include poly (meth) acrylates of polyhydric alcohols having 3 to 40 carbon atoms and their AO adducts [trimethylol propantri (meth) acrylate, tri (meth) of glycerin. Acrylate, each tri (meth) acrylate of EO3 mol and PO3 mol adduct of trimethylolpropane, each tri (meth) acrylate of EO3 mol and PO3 mol adduct of glycerin, tri (meth) acrylate of pentaerythritol, pentaerythritol Tetra (meth) acrylate, tetra (meth) acrylate of EO4 molar adduct of pentaerythritol, penta (meth) acrylate of dipentaerythritol, hexa (meth) acrylate of dipentaerythritol, etc.] and the like can be mentioned.

The polyester (meth) acrylate (C3) has a molecular weight of 150 or more having a plurality of ester bonds and 5 or more acryloyl groups obtained by esterification of a polyvalent carboxylic acid, a polyhydric alcohol, and an ester-forming acryloyl group-containing compound. And polyester acrylate of Mn 4,000 or less can be mentioned.

Examples of the polyvalent carboxylic acid include aliphatic [for example, a reaction product of malonic acid, maleic acid (anhydride), adipic acid, sebacic acid, succinic acid and acid anhydride (reactant of dipentaerythritol and maleic anhydride). Etc.)], alicyclic [eg cyclohexanedicarboxylic acid, tetrahydro (anhydride) phthalic acid and methyltetrahydro (anhydride) phthalic acid] and aromatic polyvalent carboxylic acids [eg isophthalic acid, terephthalic acid, phthalic acid (anhydride), Trimellitic acid (anhydride) and pyromellitic acid (anhydride)] and the like.

The urethane (meth) acrylate (C4) having 2 to 4 (meth) acryloyl groups includes a plurality of urethane bonds obtained by the urethanization reaction of polyisocyanate, polyol and hydroxyl group-containing (meth) acrylate and 2 to 4 urethane bonds. Examples thereof include urethane (meth) acrylates of Mn 400 to 5,000 having an acryloyl group.

Examples of the polyisocyanate used in (C4) include aliphatic polyisocyanates [hexamethylene diisocyanate, etc.], aromatic (lipid) group polyisocyanates [2,4- or 2,6-tolylene diisocyanate, 1,5-naphthalenediocyanate, etc.] And xylylene diisocyanate, etc.] and alicyclic polyisocyanate [isophorone diisocyanate and 4,4'-methylenebis (cyclohexyl isocyanate), etc.].
Examples of the polyol used in (C4) include ethylene glycol, 1,4-butanediol, neopentyl glycol, polyether polyol, polycaprolactone polyol, polyester polyol, polycarbonate polyol, and polytetramethylene glycol.
Examples of the hydroxyl group-containing (meth) acrylate used in (C4) include hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.

Examples of the epoxy (meth) acrylate (C5) include epoxy (meth) acrylates having a Mn of 400 to 5,000 obtained by the reaction of polyvalent (2 to 4 valent) epoxides with (meth) acrylic acid.

Examples of the (meth) acryloyl group-modified butadiene polymer (C6) include polybutadiene poly (meth) acrylate (Mn 500 to 500,000) having a (meth) acryloyl group in the main chain and / or side chain.

The (meth) acryloyl group-modified dimethylpolysiloxane polymer (C7) is a Mn 300 to 20,000 dimethylpolysiloxane poly (meth) acrylate having a (meth) acryloyl group in the main chain and / or side chain and condensed. Examples include things other than the thing (A).

Of these (C1) to (C7), (C2) to (C7) are preferable from the viewpoint of hardness of the cured product, and (C2) and (C4) are more preferable. Further, from the viewpoint of adhesion and flexibility, a monofunctional (meth) acrylate may be used in combination. In (C), one type may be used alone or two or more types may be used in combination.

The polyfunctional (meth) acrylate (C) in the present invention preferably has a reactive group capable of reacting with a hydroxyl group in the condensate of the metal alkoxide (a).
Examples of the reactive group capable of reacting with the hydroxyl group include a hydroxyl group, a carboxyl group, an amino group, a thiol group, a sulfonic acid group, a phosphoric acid group and an amide group. The reactive group reacts with the hydroxyl group in the condensate (A) of the metal alkoxide (a) to form a chemical bond at the organic-inorganic interface, so that high hardness is developed. Of these functional groups, a hydroxyl group, a carboxyl group and a phosphoric acid group are preferable, a hydroxyl group and a carboxyl group are more preferable, and a hydroxyl group is the most preferable.

Specific examples of polyfunctional methacrylate having a hydroxyl group in the molecule include tri (meth) acrylate of pentaerythritol, tri (meth) acrylate of EO adduct of pentaerythritol, penta (meth) acrylate of dipentaerythritol, and dipentaerythritol. Tetra (meth) acrylate, tri (meth) acrylate of dipentaerythritol, penta (meth) acrylate of EO adduct of dipentaerythritol, tripentaerythritol poly (n = 2-7) (meth) acrylate and the like. ..

Polyfunctional methacrylate having a hydroxyl group in the molecule can be obtained by an ester reaction between a polyhydric alcohol and acrylic acid or methacrylic acid, but is generally obtained as a mixture of different numbers of ester bonds (that is, the number of hydroxyl groups). Be done. For example, when 6 mol of acrylic acid is reacted with 1 mol of dipentaerythritol having 6 hydroxyl groups to produce hexaacrylate of dipentaerythritol, pentaacrylate of dipentaerythritol having 1 hydroxyl group or 2 hydroxyl groups is produced. Tetraacrylate of dipentaerythritol having a by-product also forms a mixture thereof.
In the present invention, polyfunctional methacrylate having a hydroxyl group in the molecule can be used as it is in the above mixture.

The photopolymerization initiator (D) added to the photocurable resin composition in the present invention polymerizes a polymerizable unsaturated compound by exposure to radiation such as visible light, ultraviolet rays, far infrared rays, charged particle rays and X-rays. Any component that generates a radical that can be initiated may be used.

Examples of the photopolymerization initiator (D) added to the photocurable resin composition of the present invention include a phosphine oxide-based compound (D1), a benzoylformate-based compound (D2), a thioxanthone-based compound (D3), and an oxime ester-based compound. Examples thereof include compound (D4), hydroxybenzoyl compound (D5), benzophenone compound (D6), ketal compound (D7) and 1,3αaminoalkylphenone compound (D8).

Examples of the phosphine oxide compound (D1) include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
Examples of the benzoylformate compound (D2) include methylbenzoylformate and the like.
Examples of the thioxanthone compound (D3) include isopropylthioxanthone and the like.

Examples of the oxime ester compound (D4) include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)] and etanone, 1- [9-ethyl-6- (2). -Methylbenzoyl) -9H-carbazole-3-yl]-, 1 (O-acetyloxime) and the like.
Examples of the hydroxybenzoyl compound (D5) include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, benzoin alkyl ether and the like.

Examples of the benzophenone compound (D6) include benzophenone and the like.
Examples of the ketal-based compound (D7) include benzyldimethyl ketal and the like.
Examples of the 1,3α aminoalkylphenone compound (D8) include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one.

Among these photopolymerization initiators (D), (D1), (D5) and (D8) are preferable from the viewpoint of curability, and bis (2,4,6-trimethylbenzoyl) is more preferable. ) -Phenylphosphine oxide, 1-hydroxycyclohexylphenylketone and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one.
The photopolymerization initiator (D) may be used alone or in combination of two or more.

The content of the condensate (A) in the photocurable resin composition of the present invention is 5 to 80% by weight based on the total weight of (A) to (D) from the viewpoint of the balance between hardness and transparency. It is preferably 10 to 70% by weight, and particularly preferably 20 to 75% by weight. If it is less than 5% by weight, the hardness may be insufficient, and if it exceeds 80% by weight, the transparency may be deteriorated.

The content of urethane (meth) acrylate (B) having 6 to 15 (meth) acryloyl groups in the photocurable resin composition of the present invention is (A) to (D) from the viewpoint of the balance between hardness and transparency. ), It is preferably 5 to 80% by weight, more preferably 10 to 60% by weight.

The content of the polyfunctional (meth) acrylate (C) in the photocurable resin composition of the present invention is 5 to 5 based on the total weight of (A) to (D) from the viewpoint of the balance between hardness and transparency. It is preferably 75% by weight, more preferably 10 to 60% by weight.

The content of the photopolymerization initiator (D) in the photocurable resin composition of the present invention is 0.1 to 10 based on the total weight of (A) to (D) from the viewpoint of curability and transparency. It is preferably% by weight, more preferably 0.2 to 7% by weight.

The photocurable resin composition of the present invention can contain a surfactant (E) for the purpose of improving leveling. Examples of the surfactant (E) include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, fluorine-based surfactants, silicon-based surfactants, and the like, and leveling. From the viewpoint of properties, a fluorine-based surfactant and a silicon-based surfactant are preferable, and from the viewpoint of compatibility, a surfactant having an oxyalkyl chain is preferable.

The photocurable resin composition of the present invention may contain various additives as necessary, as long as the effects of the present invention are not impaired.
Examples of the additive include a plasticizer, an organic solvent, a dispersant, a defoaming agent, a thixotropy-imparting agent (thickener), a slip agent, an antioxidant, a hindered amine-based light stabilizer, and an ultraviolet absorber. As the additive, one type may be used alone or two or more types may be used in combination.

At the time of coating, the photocurable resin composition of the present invention may contain a solvent, if necessary, in order to adjust the viscosity to be suitable for coating.
The amount of the solvent used is preferably 2,000% by weight or less, more preferably 10 to 500% by weight, based on the total weight of (A) to (D). The viscosity of the photocurable resin composition is, for example, 5 to 5,000 mPa · s at the temperature during use (for example, 5 to 60 ° C.), preferably 50 to 1,000 mPa · s from the viewpoint of stable coating. be.

The solvent is not particularly limited as long as it dissolves the resin component in the composition of the present invention. Specifically, aromatic hydrocarbons (eg toluene, xylene and ethylbenzene), esters or ether esters (eg ethyl acetate, butyl acetate and methoxybutyl acetate), ethers (eg diethyl ether, tetrahydrofuran, ethylene glycol monoethyl ether, ethylene). Glycol monobutyl ether, propylene glycol monomethyl ether and diethylene glycol monoethyl ether), ketones (eg acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone and cyclohexanone), alcohols (eg methanol, ethanol, n- or i-propanol) , N-, i-, sec- or t-butanol, 2-ethylhexyl alcohol and benzyl alcohol), amides (eg dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.), sulfoxides (eg dimethylsulfoxide), water and these. Two or more mixed solvents can be mentioned.

Among these solvents, esters, ketones and alcohols having a boiling point of 70 to 100 ° C. are preferable from the viewpoint of smoothness of the coating film and efficiency of solvent removal, and ethyl acetate, methyl ethyl ketone, i-propanol and these are more preferable. It is a mixture.

The photocurable resin composition of the present invention is applied to at least a part of at least one side of a base material, dried if necessary, and then cured by irradiation with active energy rays (ultraviolet rays, electron beams, X-rays, etc.). Therefore, a hard coat coating having a cured film can be obtained.

For coating, for example, a coating machine [bar coater, gravure coater, roll coater (size press roll coater, gate roll coater, etc.), air knife coater, spin coater, blade coater, etc.] can be used.

The coating film thickness is preferably 0.5 to 300 μm as the film thickness after curing and drying. The upper limit of the film thickness more preferable from the viewpoint of drying property and curability is 250 μm, and the lower limit further preferable from the viewpoint of abrasion resistance and coating suitability is 1 μm.

Examples of the base material include those made of resins such as methyl methacrylate (co) polymer, polyethylene terephthalate, polycarbonate, polytriacetyl cellulose and polycycloolefin.

When the photocurable resin composition of the present invention contains a solvent, it is preferable to dry it after coating. Examples of the drying method include hot air drying (dryer, etc.).
The drying temperature is preferably 50 to 200 ° C., a more preferable upper limit is 150 ° C. from the viewpoint of hardness and appearance of the coating film, and a further preferable lower limit is 60 ° C. from the viewpoint of observation speed.

When the photocurable resin composition of the present invention is cured by ultraviolet rays, various ultraviolet irradiation devices [for example, ultraviolet irradiation devices [model number "VPS / I600", manufactured by Fusion UV Systems Co., Ltd.] and LED irradiation devices are used. can.
Examples of the lamp used include a high-pressure mercury lamp and a metal halide lamp. The dose of ultraviolet rays is preferably a flexible viewpoint of curability and cured product of a composition 10~10,000mJ / cm ^2, more preferably from 100~5,000mJ / cm ^2.

The haze of the cured product of the photocurable resin composition of the present invention is preferably 1% or less. If it exceeds 1%, the transparency of the cured product deteriorates. As described in the examples, the haze of the cured product is measured by measuring the film of the cured film with a total light transmittance measuring device in accordance with JIS K7105.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Hereinafter, the part represents a weight part. Example 4 is Reference Example 1.

Production Example 1 [Production of an acrylate (C-1) solution of a condensate of tetraethoxysilane (A-1)]
67 parts of acrylate (C-1) (composition will be described later; the same applies to the following acrylates), 1.51 parts of water and tetraethoxysilane (a) in a reaction vessel equipped with a stirrer, a cooling pipe, a blow pipe and a thermometer. -1) [Product name: Dynasylan Silver Condensed, manufactured by Evonik Japan Co., Ltd.] 33 parts were charged and stirred for 30 minutes, then 0.1 part of paratoluenesulfonic acid was charged and reacted at 65 ° C. for 2 hours. Then, the reaction vessel was depressurized, and while blowing air, topping was performed at 70 ° C. for 2 hours to obtain an acrylate (C-1) solution of a condensate of tetraethoxysilane (A-1).

Production Example 2 [Production of an acrylate (C-2) solution of a condensate of tetraethoxysilane (A-2)]
43 parts of acrylate (C-2), 1.51 parts of water and 57 parts of tetraethoxysilane (a-1) were charged in a reaction vessel equipped with a stirrer, a cooling pipe, a blow pipe and a thermometer, and stirred for 30 minutes. After that, 0.1 part of paratoluenesulfonic acid was charged and reacted at 65 ° C. for 2 hours. Then, the reaction vessel was depressurized, and while blowing air, topping was performed at 70 ° C. for 2 hours to obtain an acrylate (C-2) solution of a condensate of tetraethoxysilane (A-2).

Production Example 3 [Production of acrylate (C-3) solution of condensate (A-3) of tetra-n-butoxytitanium]
67 parts of acrylate (C-3), 0.01 part of water and tetra-n-butoxytitanium (a-2) [trade name: B] in a reaction vessel equipped with a stirrer, a cooling pipe, a blow pipe and a thermometer. -1, Nippon Soda Co., Ltd.] 33 parts were charged and stirred for 30 minutes, then 0.1 part of paratoluenesulfonic acid was charged and reacted at 65 ° C. for 2 hours. Then, the reaction vessel was depressurized and topped at 70 ° C. for 2 hours while blowing air to obtain an acrylate (C-3) solution of a condensate of tetra-n-butoxytitanium (A-3).

Production Example 4 [Production of a solution of a condensate of tetraethoxysilane (A-4) with acrylates (C-1) and (C-4)]
33 parts of acrylate (C-1), 33 parts of acrylate (C-4), 1.29 parts of water and tetraethoxysilane (a-1) in a reaction vessel equipped with a stirrer, a cooling pipe, a blow pipe and a thermometer. ) 34 parts were charged and stirred for 30 minutes, then 0.1 part of paratoluenesulfonic acid was charged and reacted at 65 ° C. for 2 hours. Then, the reaction vessel is depressurized, and while blowing air, topping is performed at 70 ° C. for 2 hours to obtain a solution of a condensate of tetraethoxysilane (A-4) with acrylate (C-1) and acrylate (C-4). rice field.

Production Example 5 [Production of a solution of a condensate of tetraethoxysilane (A-5) with acrylates (C-1) and (C-5)]
12 parts of acrylate (C-1), 12 parts of acrylate (C-5), 1.65 parts of water and tetraethoxysilane (a-1) in a reaction vessel equipped with a stirrer, a cooling pipe, a blow pipe and a thermometer. ) 40 parts were charged and stirred for 30 minutes, then 0.1 part of paratoluenesulfonic acid was charged and reacted at 65 ° C. for 2 hours. Then, the reaction vessel is depressurized, and while blowing air, topping is performed at 70 ° C. for 2 hours to obtain a solution of a condensate of tetraethoxysilane (A-5) with acrylate (C-1) and acrylate (C-5). rice field.

Production Example 6 [Production of acrylate (C-1) solution of condensate of tetraethoxysilane (A-6)]
50 parts of acrylate (C-1), 30 parts of ethanol, 30 parts of formic acid and 50 parts of tetraethoxysilane (a-1) are charged in a reaction vessel equipped with a stirrer, a cooling pipe, a blow pipe and a thermometer for 30 minutes. After stirring, the reaction was carried out at 65 ° C. for 2 hours. Then, the reaction vessel was depressurized, and while blowing air, topping was performed at 70 ° C. for 2 hours to obtain an acrylate (C-1) solution of a condensate of tetraethoxysilane (A-6).

Production Example 7 [Production of an acrylate (C-1) solution of a condensate of tetraethoxysilane (A-7)]
25 parts of acrylate (C-1), 0.60 part of water and 75 parts of tetraethoxysilane (a-1) were charged in a reaction vessel equipped with a stirrer, a cooling pipe, a blow pipe and a thermometer, and stirred for 30 minutes. After that, 0.1 part of paratoluenesulfonic acid was charged and reacted at 65 ° C. for 2 hours. Then, the reaction vessel was depressurized, and while blowing air, topping was performed at 70 ° C. for 2 hours to obtain an acrylate (C-1) solution of a condensate of tetraethoxysilane (A-7).

Production Example 8 [Production of 15-functional urethane acrylate (B-1)]
In a reaction vessel equipped with a stirrer, a cooling tube, a blowing tube and a thermometer, 80 parts of acrylate (C-1) and a nulate of hexamethylene diisocyanate (b-1) [trade name: Duranate TPA-100, Asahi Kasei (trade name: Duranate TPA-100, Asahi Kasei) Made by Co., Ltd.] 20 parts, was charged and stirred for 30 minutes, then 0.5 part of bismastri (2-ethylhexanoate) (2-ethylhexanoate 50% by weight solution) was charged as a urethanization catalyst, and 6 at 80 ° C. The reaction was carried out for a time to obtain a 15-functional urethane acrylate (B-1) of dipentaerythritol pentaacrylate and a nurate compound of hexamethylene diisocyanate.

Production Example 9 [Production of 15-functional urethane acrylate (B-2)]
In a reaction vessel equipped with a stirrer, a cooling tube, a blowing tube and a thermometer, 80 parts of an acrylate (C-1) solution of the tetraethoxysilane condensate (A-1) obtained in Production Example 1 and hexamethylene. 6.7 parts of diisocyanate nurate (b-1) was charged and stirred for 30 minutes, and then 0.5 part of bismastri (2-ethylhexanoate) (2-ethylhexanoic acid 50% by weight solution) as a polycondensation catalyst. Was charged and reacted at 80 ° C. for 6 hours to obtain a 15-functional urethane acrylate (B-2) of a dipentaerythritol pentaacrylate containing a condensate of tetraethoxysilane (A-1) and a nurate compound of hexamethylene diisocyanate. rice field.

Production Example 10 [Production of 9-functional urethane acrylate (B-3)]
75 parts of acrylate (C-2), biuret of hexamethylene diisocyanate (b-2) [trade name: 24A-100, Asahi Kasei (trade name: 24A-100, Asahi Kasei) in a reaction vessel equipped with a stirrer, cooling tube, blow tube and thermometer. Made by Co., Ltd.] 25 parts were charged and stirred for 30 minutes, then 0.5 part of bismastri (2-ethylhexanoate) (2-ethylhexanoate 50% by weight solution) was charged as a urethanization catalyst, and 6 at 80 ° C. The reaction was carried out for a time to obtain a nine-functional urethane acrylate (B-3) of pentaerythritol triacrylate and a biuret form of hexamethylene diisocyanate.

Production Example 11 [Production of 6-functional urethane acrylate (B-4)]
In a reaction vessel equipped with a stirrer, cooling tube, blow tube and thermometer, 65 parts of acrylate (C-2), 35 parts of isophorone diisocyanate (b-3) [trade name: IPDI, manufactured by BASF Co., Ltd.], Was charged and stirred for 30 minutes, then 0.5 part of bismastri (2-ethylhexanoate) (2-ethylhexanoate 50% by weight solution) was charged as a urethanization catalyst and reacted at 80 ° C. for 6 hours. A hexafunctional polyfunctional urethane acrylate (B-4) of acrylate and isophorone diisocyanate was obtained.

Comparative Production Example 1 [Production of a phenoxyethyl acrylate (C'-1) solution of a tetraethoxysilane condensate (A'-1)]
Phenoxyethyl acrylate (C'-1) [trade name: light acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.] 57 parts, water 1 in a reaction vessel equipped with a stirrer, a cooling pipe, a blow pipe and a thermometer. After charging .51 parts and 43 parts of tetraethoxysilane (a-1) and stirring for 30 minutes, 0.1 part of paratoluenesulfonic acid was charged and reacted at 65 ° C. for 2 hours. Then, the reaction vessel was depressurized and topped with air at 70 ° C. for 2 hours to obtain a solution of a condensate of tetraethoxysilane (A'-1) with phenoxyethyl acrylate (C'-1). This is a condensate solution of a metal alkoxide for Comparative Example 2 in that it uses a monofunctional (C'-1).

Comparative Production Example 2 [Production of Urethane Acrylate (B'-1) Having Two Acryloyl Groups]
In a reaction vessel equipped with a stirrer, a cooling tube, a blowing tube and a thermometer, 65 parts of hydroxyethyl acrylate [trade name: BHEA, manufactured by Nippon Catalyst Co., Ltd.] and 35 parts of isophorone diisocyanate (b-3) are charged 30. After stirring for 1 minute, 0.5 part of bismastri (2-ethylhexanoate) (2-ethylhexanoate 50% by weight solution) was charged as a urethanization catalyst and reacted at 80 ° C. for 6 hours to provide a comparative example of hydroxyethyl. A bifunctional urethane acrylate (B'-1) of acrylate and isophorone diisocyanate was obtained.

The raw materials used in the production examples and the comparative production examples are as follows.
(A-1): Tetraethoxysilane [trade name "Dynasylan Silver Condensed", manufactured by Evonik Japan Co., Ltd.]
(A-2): Tetra-n-butoxytitanium [trade name "B-1", manufactured by Nippon Soda Co., Ltd.]
(C-1): Aronix M-403 [Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate manufactured by Toagosei Co., Ltd. (penta proportion = 55 mol%)]
(C-2): ETERMER235 [manufactured by Choko Kagaku Co., Ltd., the main component is pentaerythritol triacrylate (1 hydroxyl group), but also contains pentaerythritol tetraacrylate (0 hydroxyl groups) and pentaerythritol diacrylate (2 hydroxyl groups). ]
(C-3): Neomer EA-300 [manufactured by Sanyo Chemical Industries, Ltd., the main component is pentaerythritol tetraacrylate (0 hydroxyl groups), but also contains pentaerythritol triacrylate (1 hydroxyl group). ]
(C-4): Dipentaerythritol hexaacrylate (D-4) [Product name: Light acrylate DPE-6A, manufactured by Kyoeisha Chemical Co., Ltd.]
(C-5): New Frontier MF-001 [manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., the main component is dipentaerythritol EO adduct hexaacrylate (zero hydroxyl group), but dipentaerythritol EO adduct pentaacrylate (hydroxyl group 1) Includes). ]
(C-6): Aronix M-315 [manufactured by Toagosei Co., Ltd., isocyanuric acid EO-modified triacrylate]
(C'-1): Phenoxyethyl acrylate [Product name: Light acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.]

Example 1
90 parts of the (meth) acrylate (C-1) solution of the tetraethoxysilane condensate (A-1) obtained in Production Example 1 was placed in a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, Production Example. 10 parts of 15-functional urethane acrylate obtained in 8, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one (D-2) [trade name "Irgacure 907", Made by BASF] 3 parts and 1 part of a fluorine atom-containing nonionic surfactant (E-2) were added, and the mixture was mixed and stirred at 65 ° C. until uniform to obtain a photocurable resin composition (F-1). ..

Examples 2-8 and Comparative Examples 1-6
In the same manner as in Example 1, the photocurable resin compositions (F-2) to (F-8) and (F'-1) to (F'-6) were uniformly mixed in the number of parts (parts by weight) shown in Table 1. ) Was obtained.
In addition, since Table 1 shows the amounts of (A) and (C) of the acrylate (C) solution of the condensate (A) obtained in the production example separately, the production used for compounding is shown separately. The amount of the solution (C) of (A) obtained in the example is the total value of the condensate (A) and the acrylate (C) in Table 1.
Further, in Comparative Examples 3 and 4, instead of synthesizing (A) in (C) as in the present invention, commercially available inorganic oxide fine particles (A'-2) and (A'-3) are solidified. It was blended so that each minute was 30% by weight.

The raw materials used in Table 1 are as follows.
(A'-2): Silica fine particles [trade name "coloidal silica MEK-ST" particle size 10-15 nm MEK 40% by weight solution, manufactured by Nissan Chemical Industries, Ltd.]
(A'-3): Acryloyl-modified silica fine particles [trade name "MEK-AC" particle size 10-15 nm MEK 40% by weight solution, manufactured by Nissan Chemical Industry Co., Ltd.]
(D-1): 1,3,5-trimethylbenzoyldiphenylphosphine oxide [trade name "Lucillin TPO", manufactured by BASF Limited]
(D-2): 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one [trade name "Irgacure 907", manufactured by BASF Limited]
(D-3): 1-Hydroxycyclohexylphenyl ketone [trade name "Irgacure 184", manufactured by BASF Ltd.]

The performance of the film obtained by curing the photocurable resin composition was evaluated by the following method. The evaluation results are shown in Table 1.

<Curing film manufacturing method>
The photocurable resin compositions (F-1) to (F-8) and (F'-1) to (F'-6) are diluted with propylene glycol monomethyl ether or methyl ethyl ketone using a disperser, respectively, to obtain a non-volatile component. Prepared to 40% by weight.
Using a bar coater on one side of a TAC film substrate with a thickness of 40 μm, apply it so that the film thickness after drying and curing is 7 μm, dry it at 70 ° C. for 1 minute, and then use an ultraviolet irradiation device [model number “VPS / I600”. , Made by Fusion UV Systems Co., Ltd. same as below. ], A film having a cured film on the surface of the base film was prepared by irradiating with ultraviolet rays at 300 mJ / cm ^{2 in a nitrogen atmosphere.}

[Evaluation of scratch resistance]
The resin surface of the film having the cured film obtained by the above operation was rubbed 100 times back and forth with a load of ^{2000 g / cm 2 using # 0000 steel wool.}
The haze values (%) before and after rubbing are measured in accordance with JIS K7105 using a total light transmittance measuring device [trade name "haze-gard dual" manufactured by BYK gardner Co., Ltd.], and after rubbing. The difference between the haze value of and the haze value (%) before scraping was calculated.
Under these evaluation conditions, the difference in haze values is generally preferably 1% or less.

[Evaluation of pencil hardness]
The pencil hardness of the film having the cured film obtained by the above operation was measured according to JIS K-5400.
Under these evaluation conditions, 3H or more is generally preferable.

[Evaluation of haze (film transparency)]
The haze of the film having the cured film obtained by the above operation was measured using a total light transmittance measuring device [trade name "haze-gard dual" manufactured by BYK gardener Co., Ltd.] in accordance with JIS-K7105. ..
The haze value of the cured product of the present invention needs to be 1.0% or less.

[Measurement of total light transmittance (transparency of composition)]
Place a 100 μm-thick silicone rubber hollowed out in a 2 cm square on a 1 mm thick slide glass, pour the photocurable resin composition into the hollowed out part, sandwich it with another slide glass, and clip it. The total light transmittance (%) was measured using a total light transmittance measuring device [trade name "haze-gard dual", manufactured by BYK gardener Co., Ltd.] in accordance with JIS-K7105 fixed at both ends.
The total light transmittance of the composition of the present invention needs to be 90% or more.

As shown in Table 1, the photocurable resin compositions of Examples 1 to 8 of the present invention are excellent in all aspects of scratch resistance, pencil hardness and transparency.
On the other hand, Comparative Example 1 in which the condensate of the metal alkoxide was not used had a poor pencil hardness, and a monofunctional phenoxyethyl acrylate (C'-1) was used instead of the 3 to 6 functional (meth) acrylate (C). Comparative Example 2 using (A'-2) has poor scratch resistance and pencil hardness. Further, Comparative Example 6 in which bifunctional urethane acrylate (B'-1) is used instead of 6 to 15 functional urethane (meth) acrylate (B) also has poor scratch resistance and pencil hardness. In Comparative Example 3 in which the metal-participating fine particles (A'-2) were used instead of the metal alkoxide condensate (A) and Comparative Example 4 in which (A'-3) was used, in addition to scratch resistance and pencil hardness, Transparency is also poor. Comparative Example 5 in which 6 to 15 functional urethane (meth) acrylate (B) is not used has poor scratch resistance.

The hard coat film having a hard coat film obtained by curing the photocurable resin composition of the present invention is excellent in scratch resistance, pencil hardness and transparency, and therefore is used for display-related members such as smartphones and televisions, and plastics. It can be used for optical components, in-vehicle decorative films, head-up display (HUD) combiners, automobile window coatings, and the like. For example, it is suitable for fields having excellent surface hardness and transparency such as flat panel displays, touch panels, and combiners.

Claims (5)

Other than the condensate (A) of the metal alkoxide (a) represented by the following general formula (1), the polyfunctional urethane (meth) acrylate (B) having 6 to 15 (meth) acryloyl groups, and (B). Contains the polyfunctional (meth) acrylate (C) and the photopolymerization initiator (D) .
The polyfunctional (meth) acrylate (C) is a compound having a hydroxyl group in the molecule, and is
The condensate (A) of the metal alkoxide (a) is a condensate of the metal alkoxide (a) formed by reacting the metal alkoxide (a) in the polyfunctional (meth) acrylate (C).
A photocurable resin composition having a content of (B) of 5 to 60% by weight based on the total weight of (A) to (D).

[In the formula (1), R ¹ and R ² are independent ester compounds having one or more hydroxyl groups of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a polyhydric alcohol, and (meth) acrylic acid (meth). Represents a residue obtained by removing one hydroxyl group from d), and R ³ and R ⁴ independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and one or more of a polyhydric alcohol and (meth) acrylic acid. Represents a residue obtained by removing one hydroxyl group from the ester compound (d) having a hydroxyl group of, or a metal atom-containing group represented by the following general formula (2), and a plurality of R ³ and R ⁴ are the same, respectively. M may represent a silicon atom, a titanium atom or a zirconium atom, and a plurality of M may be the same or different, and n is an integer of 2 to 15. ]

[In formula (2), R ⁵ , R ⁶ and R ⁷ are esters having one or more hydroxyl groups of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a polyhydric alcohol and (meth) acrylic acid, respectively. Represents a residue obtained by removing one hydroxyl group from compound (d), and when there are a plurality of R5 and R6, they may be the same or different, and M represents a silicon atom, a titanium atom or a zirconium atom. A plurality of M's may be the same or different, and k is an integer of 1 to 5. ] ^{An ester compound in which at least one of R 1 to} R ⁴ in the general formula (1) ^{and R 5 to} R ⁷ in the general formula (2) has one or more hydroxyl groups of a polyhydric alcohol and (meth) acrylic acid. It is a residue obtained by removing one hydroxyl group from (d), and the condensate (A) of the metal alkoxide (a) represented by the general formula (1) is one of a polyhydric alcohol and (meth) acrylic acid. The photocurable resin composition according to claim 1, wherein the ester compound (d) having the above hydroxyl groups has at least one residue obtained by removing one hydroxyl group. Claimed that the residue obtained by removing one hydroxyl group from the ester compound (d) having one or more hydroxyl groups of a polyhydric alcohol and (meth) acrylic acid is an organic group represented by the following general formula (3). Item 3. The photocurable resin composition according to Item 1 or 2.

[In equation (3), m is an integer from 0 to 5. ] The polyfunctional urethane (meth) acrylate (B) has a bifunctional or trifunctional polyisocyanate compound (b), a (meth) acryloyl group of 3 to 5, and a (meth) acrylate (c) having at least one hydroxyl group. The photocurable resin composition according to any one of claims 1 to 3, which is a urethane compound of the above. The photocurable resin composition according to any one of claims 1 to 4 , wherein the content of (A) is 5 to 80% by weight based on the total weight of (A) to (D).