JP2018070839A - Photocurable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocurable resin composition giving a cured matter whose transparency is not damaged even if it contains an organic matter and also having high hardness.SOLUTION: Provided is a photocurable resin composition containing: the condensate(A) of a metalalkoxide (a); polyfunctional acrylate (B); and a photoinitiator (C), in which the condensate (A) is expressed by the following general formula (1), the content of the (A) is 25 to 80 wt.% based on the total weight of the (A) to (C), and the haze value of the cured matter is 1% or lower[in the general formula (1), Rand Rdenote a hydrogen atom, a 1 to 4C alkyl group or a residue obtained by removing one hydroxyl group from an ester compound (d) having one or more hydroxyl groups of polyalcohol and (meth)acrylic acid; Rand Rdenotes a hydrogen atom, a 1 to 4C alkyl group or a residue obtained by removing a hydroxyl group from the ester compound (d) of polyalcohol and (meth)acrylic acid; and M denotes silicon or zirconium atoms.SELECTED DRAWING: None

Description

  The present invention relates to a photocurable resin composition. In detail, it is related with the photocurable resin composition which is excellent in transparency and gives the hardened | cured material which has high hardness.

In recent years, display devices such as a liquid crystal display and a touch panel display provided with a film having a hard coat film as a protective layer on the surface thereof are rapidly spreading. In particular, electronic devices such as smartphones and tablet terminals equipped with a touch panel that is operated by directly touching the screen with a finger or a pen are remarkably 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 that is safer and lighter than glass. However, these resins have a drawback in that they are inferior in hardness to glass.

For this reason, there is known a method of forming a hard coat layer mainly composed of an active energy ray-curable resin containing high-hardness silica fine particles as a filler, but inorganic silica fine particles are organic active energy rays. Since it is difficult to disperse uniformly in the monomer of the cured resin, a technique for improving the dispersibility by performing an organic treatment on the surface of the silica fine particles has been performed (Patent Documents 1 to 3).
However, the ultraviolet curable resin composition prepared 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.

JP 2000-264621 A JP2015-86103A Japanese Patent Laying-Open No. 2015-36402

  An object of this invention is to provide the photocurable resin composition which gives the hardened | cured material which does not impair transparency even if it contains a large amount of an inorganic substance and has high hardness.

The inventors of the present invention have reached the present invention as a result of studies to achieve the above object.
That is, this invention contains the condensate (A), polyfunctional acrylate (B), and photoinitiator (C) of metal alkoxide (a), and the condensate (A) is the following general formula (1). The photocurability is characterized in that the content of (A) is 25 to 80% by weight based on the total weight of (A) to (C), and the haze value of the cured product is 1% or less. It is a resin composition.

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

[In General Formula (2), R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an ester compound (d) of a polyhydric alcohol and (meth) acrylic acid. Represents a residue from which a hydroxyl group has been removed, and a plurality of R ⁵ and R ⁶ may be the same or different. M represents a silicon, titanium or zirconium atom. k is an integer of 1-5. ]

  Even if the photocurable resin composition of the present invention contains a large amount of an inorganic material, the transparency is not impaired, and a cured product having high hardness can be obtained.

The photocurable resin composition of the present invention contains a metal alkoxide condensate (A), a polyfunctional (meth) acrylate (B), and a photopolymerization initiator (C), and is a total of (A) to (C). Based on the weight, the content of the condensate (A) of the metal alkoxide is 25 to 80% by weight, and the haze value of the cured product is 1% or less. This metal alkoxide condensate (A) is represented by the following general formula (1).

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

In the general formula (2), R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an ester compound (d) of a polyhydric alcohol and (meth) acrylic acid. This represents a residue excluding a hydroxyl group, and a plurality of R ⁵ and R ⁶ may be the same or different. M represents a silicon, titanium or zirconium atom. k is an integer of 1-5.

In this specification, “(meth) acrylate” means “acrylate or methacrylate”, “(meth) acrylic acid” means “acrylic acid or methacrylic acid”, and “(meth) acryloyl group” means “ It means “acryloyl group or methacryloyl group”.

The condensate (A), polyfunctional (meth) acrylate (B) and photopolymerization initiator (C) of the essential component metal alkoxide (a) will be described below in sequence.

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

In the general formula (1), R ¹ and R ² each independently have a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or one or more hydroxyl groups of a polyhydric alcohol and (meth) acrylic acid. It represents a residue obtained by removing one hydroxyl group from the ester compound (d).

Here, the ester compound of polyhydric alcohol and (meth) acrylic acid is an ester compound in which at least one hydroxyl group remains in an ester reaction product obtained by reacting polyhydric alcohol with acrylic acid or methacrylic acid. The organic group that can be used as R ¹ and R ² is a residue obtained by removing one hydroxyl group from this ester compound.

  Examples of polyhydric alcohols include ordinary alcohols in which hydrocarbons such as ethylene glycol, 1,4-butylene glycol, glycerin, trimethylolpropane, and pentaerythritol are substituted with hydroxyl groups; diethylene glycol, triethylene glycol, dipenta as derivatives thereof Examples include erythritol and tripentaerythritol.

Examples of ester compounds in which at least one hydroxyl group remains in the ester reaction product of these polyhydric alcohol and acrylic acid include ethylene glycol mono (meth) acrylate, butylene glycol mono (meth) acrylate, glycerin mono (meth) acrylate, Glycerin di (meth) acrylate, trimethylolpropane mono (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol mono (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol di (meth) acrylate, di Examples include pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and tripentaerythritol hepta (meth) acrylate.
Among these, preferred ester compounds include pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol hepta (meth) acrylate, and the like.

The residue obtained by removing the hydroxyl group from the ester compound of polyhydric alcohol and (meth) acrylic acid is preferably an organic group represented by the following general formula (3).

In formula (3), m is an integer of 0-5.

The organic group represented by the general formula (3) is specifically a residue obtained by removing a hydroxyl group from pentaerythritol or an ester compound of dipentaerythritol or tripentaerythritol and acrylic acid as a derivative thereof.

M in the formula (3) is an integer of 0 to 5, specifically, a residue of triacrylate of pentaerythritol in which m is 0, a residue of dipentaerythritol pentaacrylate in which m is 1, m is Examples thereof include a residue of 2 pentapentaerythritol heptaacrylate, m of tetrapentaerythritol nonane acrylate of 3, m of 4 pentapentaerythritol undecane acrylate, and m of 5 pentapentaerythritol tridecane acrylate.

R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an unsaturated hydrocarbon group polyhydric alcohol represented by the above general formula (3), and (meth) acrylic acid. The residue which remove | excluded the hydroxyl group from the ester compound or the metal atom containing organic group represented by following General formula (2) is represented.

In formula (2), k is an integer of 1 to 5, preferably 1.
R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an ester compound of a polyhydric alcohol represented by the general formula (3) and (meth) acrylic acid. Represents a residue excluding a hydroxyl group.
M in the formulas (1) and (2) represents a silicon, titanium or zirconium atom, and preferably silicon or titanium from the viewpoint of hardness.

Moreover, n in Formula (1) is an integer of 2-15.

The condensate (A) of the metal alkoxide (a) according to the present invention comprises a condensate of a hydrolyzate of metal alkoxide (a) such as tetraalkoxysilane with water, and at the same time the condensate and polyhydric alcohol (meth). Obtained by condensation of an ester compound with acrylic acid.

By coexisting an ester compound of a metal alkoxide (a), a polyhydric alcohol, and (meth) acrylic acid, at least one of R ^{1 to} R ^{4 in} the general formula (1) is represented by the general formula (3). It is a residue obtained by removing a hydroxyl group from an ester compound of a polyhydric alcohol and (meth) acrylic acid, or at least one of R ⁵ and R ^{6 in} the general formula (2) is represented by the general formula (3 When the residue is a residue obtained by removing a hydroxyl group from an ester compound of a polyhydric alcohol represented by () and (meth) acrylic acid, the pencil hardness is remarkably improved.

In the present invention, the reaction is preferably performed in the presence of the catalyst (b), and examples of the catalyst (b) include an acid catalyst (b1) and a base catalyst (b2).

Examples of the acid catalyst (b1) include inorganic acids and organic acids. Examples of the inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and boric acid.
Examples of the organic acid include sulfonic acid, carboxylic acid, hydroxy acid, and oxalic acid.

  Examples of the base catalyst (b2) include metal hydroxides and organic amines, and examples of the metal hydroxides include sodium hydroxide, potassium hydroxide, and lithium hydroxide.

Examples of organic amines include aliphatic amines, alicyclic amines, aromatic amines, and heterocyclic amines.
Examples of the aliphatic amine include mono- having 1 to 18 carbon atoms in the alkyl group such as hexylamine, octylamine, methylhexylamine, methyloctylamine, dimethylhexylamine, dimethyloctylamine, dimethyllaurylamine, and dimethylcetylamine, Di- and tri-alkylamines are mentioned.

Examples of the alicyclic amine include cycloalkylamine having 4 to 12 carbon atoms in the cycloalkyl group such as cyclobutylamine, cyclohexylamine, cyclopentylamine, cyclooctylamine, N-methylcyclohexylamine, and N-ethylcyclohexylamine, and the like. An alkyl (C1-C6) substitution product is mentioned.

Examples of the aromatic amine include aromatic amines having 6 to 18 carbon atoms such as aniline and diphenylamine.

Examples of the heterocyclic amine include heterocyclic amines having 4 to 10 carbon atoms such as morpholine.

Of these, hydrochloric acid, acetic acid, methanesulfonic acid and p-toluenesulfonic acid are preferable from the viewpoint of reactivity, and hydrochloric acid, methanesulfonic acid and p-toluenesulfonic acid are more preferable.

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

Examples of the alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Examples of these commercially available products include tetraethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.), ethyl silicate 28, ethyl silicate 28P, N -Propyl silicate, N-butyl silicate (above, Colcoat Co., Ltd.), normal methyl silicate, normal ethyl silicate, high purity ethyl silicate, high purity ethyl silicate (EL) (above, Tama Chemical Co., Ltd.), Dynasylan SILBOND CONDENSED (Evonik Japan Co., Ltd.) etc. are mentioned.

  The temperature for producing the condensate (A) of the metal alkoxide (a) is preferably 40 to 80 ° C, more preferably 60 to 70 ° C. When the temperature is higher than 40 ° C., the reaction rate is increased, so that productivity is improved. On the other hand, when the temperature is lower than 80 ° C., hydrolysis and polycondensation of the metal alkoxide can proceed without polymerization and polymerization of the polyfunctional (meth) acrylate in the reaction system.

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

The chemical bond between the hydrolysis condensate of the metal alkoxide (a) of the condensate (A) of the present invention and the ester compound of polyhydric alcohol and (meth) acrylic acid is obtained by combining the metal alkoxide and water. The reaction proceeds sufficiently under the reaction conditions for producing a metal alkoxide condensate by reaction. The temperature is preferably 40 to 80 ° C, and more preferably 60 to 70 ° C.

From the viewpoint of the balance between hardness and transparency, the content of the condensate (A) of the metal alkoxide (a) in the photocurable resin composition of the present invention is based on the total weight of (A) to (C). It is 25 to 80% by weight, preferably 30 to 70% by weight, and more preferably 30 to 60% by weight. If it is less than 25% by weight, the hardness is insufficient, and if it exceeds 80% by weight, the transparency deteriorates.

The polyfunctional (meth) acrylate (B) contained in the photocurable resin composition of the present invention is a polyfunctional (meta) having at least 2, preferably 3 to 6, (meth) acryloyl groups from the viewpoint of hardness. ) Acrylate is preferred.

  Specifically, the following di (meth) acrylate (B1), trivalent or higher (meth) acrylate (B2), polyester (meth) acrylate (B3), urethane (meth) acrylate (B4), epoxy (meth) Examples include acrylate (B5), (meth) acryloyl group-modified butadiene polymer (B6), and (meth) acryloyl group-modified dimethylpolysiloxane polymer (B7).

As the di (meth) acrylate (B1), polyoxyalkylene (alkylene having 2 to 4 carbon atoms) [molecular weight of 106 or more and number average molecular weight (hereinafter referred to as number average molecular weight by gel permeation chromatography (GPC) method) Di (meth) acrylate (B11) of 3,000 or less]: abbreviated to Mn. Each of di (meth) acrylates of polyethylene glycol (Mn400), polypropylene glycol (Mn200), and polytetramethylene glycol (Mn650). .

Further, as di (meth) acrylate (B1), an alkylene oxide of a dihydric phenol compound (hereinafter, “alkylene oxide” is abbreviated as AO) (2 to 30 mol), an adduct di (meth) acrylate: 2 Of polyhydric phenol compounds [monocyclic phenols (catechol, resorcinol, hydroquinone, etc.), condensed polycyclic phenols (dihydroxynaphthalene, etc.), bisphenol compounds (bisphenol A, -F, -S etc.)] [resorcinol EO 4 mol addition Di (meth) acrylates, di (meth) acrylates of PO4 mol adducts of dihydroxynaphthalene, EO2 mol, and PO4 mol of adducts of bisphenol A, -F and -S, etc.] Is mentioned.
Di (meth) acrylates of aliphatic dihydric alcohols having 2 to 30 carbon atoms: alicyclic divalent alcohols having 6 to 30 carbon atoms such as neopentyl glycol and 1,6-hexanediol di (meth) acrylates Di (meth) acrylate: Di (meth) acrylate of dimethyloltricyclodecane, di (meth) acrylate of cyclohexanedimethanol, and di (meth) acrylate of hydrogenated bisphenol A.

The trivalent or higher (meth) acrylate (B2) includes polyhydric alcohol having 3 to 40 carbon atoms and poly (meth) acrylate of its AO adduct, trimethylolpropane tri (meth) acrylate, and tri (meth) of glycerin. Acrylate, trimethylolpropane EO 3 mol and PO3 mol adduct tri (meth) acrylate, glycerin EO3 mol and PO3 mol adduct tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol Examples include tetra (meth) acrylate, tetra (meth) acrylate of pentaerythritol EO 4 mol adduct, penta (meth) acrylate of dipentaerythritol, hexa (meth) acrylate of dipentaerythritol, and the like.

As will be described later, the polyfunctional (meth) acrylate (B) has a reactive group (α) that reacts with a hydroxyl group in the condensate (A) of the metal alkoxide (a) to form a chemical bond. Is preferred. And, such a reactive group (α) has a hydroxyl group in the molecule, and trivalent or higher (meth) acrylate (B21) is an ester reaction product of polyhydric alcohol and acrylic acid or methacrylic acid. Having at least one of the above.
Examples of such a (meth) acrylate (B21) having a hydroxyl group in the molecule and having a valence of 3 or more include tri (meth) acrylate of pentaerythritol, tri (meth) acrylate of EO adduct of pentaerythritol, dipentaerythritol Penta (meth) acrylate, tetra (meth) acrylate (meth) acrylate of dipentaerythritol, tri (meth) acrylate of dipentaerythritol, penta (meth) acrylate of EO adduct of dipentaerythritol; tripentaerythritol polyacrylate, etc. Is mentioned.

  Furthermore, the ester reaction between a polyhydric alcohol and acrylic acid or methacrylic acid is generally not uniform in terms of chemical equivalents, but is obtained as a mixture of different numbers of ester bonds (ie, the number of hydroxyl groups). For example, when 6 moles of acrylic acid is reacted with 1 mole of dipentaerythritol having 6 hydroxyl groups to produce dipentaerythritol hexaacrylate, the pentaacrylate of dipentaerythritol having 1 hydroxyl group and 2 hydroxyl groups Dipentaerythritol tetraacrylate having a by-product is also formed as a mixture.

The polyester (meth) acrylate (B3) 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 polycarboxylic acid, a polyhydric alcohol, and an ester-forming acryloyl group-containing compound. And a polyester acrylate having a Mn of 4,000 or less.
Examples of the polyvalent carboxylic acid include aliphatic [eg, malonic acid, maleic acid (anhydride), adipic acid, sebacic acid, succinic acid, acid anhydride reaction product (reaction product of dipentaerythritol and maleic anhydride] Etc.)], alicyclic [eg cyclohexanedicarboxylic acid, tetrahydro (anhydride) phthalic acid, methyltetrahydro (anhydride) phthalic acid] and aromatic polycarboxylic acids [eg isophthalic acid, terephthalic acid, phthalic acid (anhydride), Trimellitic acid (anhydride), pyromellitic acid (anhydride)].

As the urethane (meth) acrylate (B4), Mn 400 to 5,000 urethane having a plurality of urethane bonds and two or more acryloyl groups obtained by urethanization reaction with polyisocyanate, polyol, and hydroxyl group-containing (meth) acrylate. (Meth) acrylate is mentioned.
.

Examples of the corresponding polyisocyanate include aliphatic polyisocyanate [hexamethylene diisocyanate and the like], aromatic (aliphatic) polyisocyanate [2,4- and / or 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, xylylene Range isocyanate, etc.] and alicyclic polyisocyanates [isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), etc.].
Examples of the polyol 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 include epoxy (meth) acrylate (B5) such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate and the like. ) Includes epoxy (meth) acrylates having Mn of 400 to 5,000 obtained by reaction of polyvalent (2 to 4 valent) epoxides with (meth) acrylic acid.

Examples of the (meth) acryloyl group-modified butadiene polymer (B6) include polybutadiene poly (meth) acrylate (Mn 500 to 500,000) having a (meth) acryloyl group in the main chain and / or side chain.

Examples of the (meth) acryloyl group-modified dimethylpolysiloxane polymer (B7) include Mn300 to 20,000 dimethylpolysiloxane poly (meth) acrylate having a (meth) acryloyl group in the main chain and / or side chain.
Said (B1)-(B7) may be used independently, or may use 2 or more types together. Among these (B1) to (B7), from the viewpoint of the hardness of the cured product, (B2) to (B7) are preferable, and (B2) and (B4) are more preferable. Further, from the viewpoint of adhesion and flexibility, monofunctional (meth) acrylate may be used in combination.
In order to ensure transparency when the content of the condensate (A) of the metal alkoxide (a) is increased, the same kind of polyfunctional (meth) acrylate (B) or a different kind of (B) is further added. It may be diluted.

The polyfunctional (meth) acrylate (B) of 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 a 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), and a chemical bond is generated at the organic-inorganic interface, so that high hardness is exhibited. Of these functional groups, a hydroxyl group, a carboxyl group, and a phosphate group are preferable, a hydroxyl group and a carboxyl group are more preferable, and a hydroxyl group is most preferable.
From the viewpoint of balance between hardness and transparency, the content of the polyfunctional (meth) acrylate (B) in the photocurable resin composition of the present invention is 20 based on the total weight of (A) to (C). It is -75 weight%, Preferably it is 30-60 weight%.

As a photopolymerization initiator (C) added to the photocurable resin composition of the present invention, polymerization of a polymerizable unsaturated compound is performed by exposure to radiation such as visible light, ultraviolet light, far infrared light, charged particle beam, and X-ray. Any component that generates radicals that can be initiated may be used.
As a photoinitiator (C) added to the photocurable resin composition of the present invention, a phosphine oxide compound (C1), a benzoylformate compound (C2), a thioxanthone compound (C3), an oxime ester compound Examples include compound (C4), hydroxybenzoyl compound (C5), benzophenone compound (C6), ketal compound (C7), 1,3α aminoalkylphenone compound (C8), and the like.

Examples of the phosphine oxide compound (C1) include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
Examples of the benzoylformate compound (C2) include methylbenzoylformate.
Examples of the thioxanthone compound (C3) include isopropylthioxanthone.
Examples of the oxime ester compound (C4) include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2 -Methylbenzoyl) -9H-carbazol-3-yl]-, 1 (O-acetyloxime)) and the like.
Examples of the hydroxybenzoyl compound (C5) include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and benzoin alkyl ether.
Examples of the benzophenone compound (C6) include benzophenone.
Examples of the ketal compound (C7) include benzyldimethyl ketal.
Examples of the 1,3α aminoalkylphenone compound (C8) include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one.

  Among these photopolymerization initiators (C), (C1), (C5), and (C8) are preferable from the viewpoint of curability, and more preferably bis (2,4,6-trimethylbenzoyl). -Phenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one.

Based on the total weight of (A) to (C) in the photocurable resin composition, the content of the photopolymerization initiator (C) is 0.1 to 10% by weight from the viewpoint of curability and transparency. Yes, preferably 0.2 to 7% by weight.

The photo-curable resin composition of the present invention may contain various additives as necessary within a range not inhibiting the effects of the present invention.
Examples of the additive include a plasticizer, an organic solvent, a dispersant, an antifoaming agent, a thixotropy imparting agent (thickening agent), a slip agent, an antioxidant, a hindered amine light stabilizer, and an ultraviolet absorber.

In order to adjust the viscosity of the composition of the present invention to a viscosity suitable for coating, a coating diluted with a solvent as necessary can be used.
The amount of the solvent used is 2,000% or less, preferably 10 to 500%, based on the total weight of the composition. Moreover, the viscosity of a coating material is the temperature at the time of use (for example, 5-60 degreeC), for example, is 5-5,000 mPa * s, Preferably it is 50-1,000 mPa * s from a viewpoint of stable coating.

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, monomethyl ether of propylene glycol and monoethyl ether of diethylene glycol), 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 (e.g. dimethylformamide, dimethylacetamide, N- methylpyrrolidone), sulfoxides (e.g., dimethylsulfoxide), water, and a mixed solvent of two or more thereof.
Of these solvents, from the viewpoint of the smoothness of the coating film and the efficiency of solvent removal, esters, ketones and alcohols having a boiling point of 70 to 100 ° C. are preferred, and ethyl acetate, methyl ethyl ketone, i-propanol and mixtures thereof are more preferred. It is.

The composition of the present invention is diluted with a solvent, if necessary, applied to at least a part of at least one side of the substrate, dried if necessary, and then irradiated with active energy rays (ultraviolet rays, electron beams, X-rays, etc.). A hard coat coating having a cured film can be obtained by curing with or heat.
In 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.
A coating film thickness is 0.5-300 micrometers normally as a film thickness after hardening drying. The upper limit is preferably 250 μm from the viewpoints of drying properties and curability, and the lower limit is preferably 1 μm from the viewpoints of wear resistance, solvent resistance, and contamination resistance.

Examples of the transparent substrate include those made of resins such as methyl methacrylate (co) polymer, polyethylene terephthalate, polycarbonate, polytriacetylcellulose, and polycycloolefin.

When the composition of the present invention is used after being diluted with a solvent, it is preferably dried after coating. Examples of the drying method include hot air drying (such as a dryer).
The drying temperature is usually 10 to 200 ° C., the upper limit is preferably 150 ° C. from the viewpoint of the smoothness and appearance of the coating film, and the lower limit is preferably 30 ° C. from the viewpoint of the drying 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.] can be used.
Examples of the lamp to be 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.
In addition, the haze of hardened | cured material measures a film of a cured film with a total light transmittance measuring apparatus based on JIS-K7105 so that it may explain in full detail by the measuring method of an Example.

The total light transmittance of the photocurable resin composition of the present invention is preferably 90% or more.
The total light transmittance of the present invention is measured with a total light transmittance measuring device in accordance with JIS-K7105, with the composition sandwiched between two slides, as will be described in detail in the measurement method of the examples. .

The photocurable resin composition of the present invention has a problem of providing a cured product having excellent transparency and high hardness, but generally, increasing the content of inorganic matter to increase the hardness impairs transparency. There are conflicting relationships.

When the general inorganic fine particles such as silica fine particles are mixed and dispersed in the polyfunctional (meth) acrylate (B), for example, if the content of the silica fine particles is increased to more than 25% by weight, the transparency is improved. There is a tendency to be damaged.
Therefore, when producing the photocurable resin composition of the present invention, in the polyfunctional (meth) acrylate (B), in the presence of the catalyst (b), the metal alkoxide (a) is reacted with water, It is preferable to include a step of obtaining a metal alkoxide condensate (A) that satisfies the transparency of the present invention.

Since the metal alkoxide condensate (A) contained in the photocurable resin composition of the present invention is produced by reacting in the polyfunctional (meth) acrylate (B), it is compatible with (B). It is excellent, and the hardness of the cured product is increased by containing (A) thus obtained.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

Production Example 1 [Production of tetraethoxysilane condensate (A-1) solution]
In a reaction vessel equipped with a stirrer, a cooling tube, a blowing tube, and a thermometer, 65 parts of dipentaerythritol hexaacrylate (B-1) [trade name: Neomer DA-600, manufactured by Sanyo Chemical Industries, Ltd.], water 1.51 parts and 35 parts of tetraethoxysilane (a-1) [trade name: Dynasylan Silver Condensed, manufactured by Evonik Japan Co., Ltd.] were charged and stirred for 30 minutes, and then 2.36 parts of paratoluenesulfonic acid were charged, 65 The reaction was carried out at 2 ° C. for 2 hours. Thereafter, the reaction vessel was evacuated and topped at 70 ° C. for 2 hours while blowing air to obtain a solution of tetraethoxysilane condensate (A-1) with dipentaerythritol hexaacrylate (B-1).

Production Example 2 [Production of tetraethoxysilane condensate (A-2) solution]
In a reaction vessel equipped with a stirrer, a cooling pipe, a blowing pipe and a thermometer, 65 parts of pentaerythritol triacrylate (B-2) [trade name: ETERMER 235, manufactured by Changxing Chemical Co., Ltd.], 1.51 parts of water and Tetraethoxysilane (a-1) [trade name: Dynasylan Silver Condensed, manufactured by Evonik Japan Co., Ltd.] 35 parts was charged and stirred for 30 minutes, and then 2.36 parts of paratoluenesulfonic acid was added and reacted at 65 ° C. for 2 hours. I let you. Thereafter, the reaction vessel was evacuated and topped at 70 ° C. for 2 hours while blowing air to obtain a solution of tetraethoxysilane condensate (A-2) with pentaerythritol triacrylate (B-2).

Production Example 3 [Production of tetra-n-butoxytitanium condensate (A-3) solution]
In a reaction vessel equipped with a stirrer, a cooling tube, a blowing tube and a thermometer, 65 parts of pentaerythritol tetraacrylate (B-3) [trade name: Neomer EA-300, manufactured by Sanyo Chemical Industries, Ltd.], water 0 .01 parts and 35 parts of tetra-n-butoxytitanium (a-2) [trade name: B-1, manufactured by Nippon Soda Co., Ltd.] were stirred for 30 minutes, and then 0.05 parts of paratoluenesulfonic acid was charged. And reacted at 65 ° C. for 2 hours. Thereafter, the reaction vessel was evacuated and topped at 70 ° C. for 2 hours while blowing air to obtain a solution of tetra-n-butoxytitanium condensate (A-3) with pentaerythritol tetraacrylate (B-3). .

Production Example 4 [Production of tetraethoxysilane condensate (A-4) solution]
In a reaction vessel equipped with a stirrer, a cooling pipe, a blowing pipe and a thermometer, 40 parts of dipentaerythritol hexaacrylate (B-1) [trade name: Neomer DA-600, manufactured by Sanyo Chemical Industries, Ltd.], penta Erythritol hexaacrylate (B-1) [trade name: Neomer DA-600, manufactured by Sanyo Chemical Industries, Ltd.] 65 parts, pentaerythritol tetraacrylate (B-3) [trade name: Neomer EA-300, Sanyo Chemical Industries ( Co., Ltd.] 10 parts, trimethylolpropane EO 3 mol adduct triacrylate (B-4) [trade name: Neomer TA-401, Sanyo Chemical Industries, Ltd.], 20 parts, water 1.29 parts and tetraethoxy 30 parts of silane (a-1) [trade name: Dynasylan Silver Condensed, manufactured by Evonik Japan Co., Ltd.] After stirring seen 30 minutes was charged with 2.02 parts of p-toluenesulfonic acid was allowed to react for 2 hours at 65 ° C.. Thereafter, the reaction vessel was evacuated and topped at 70 ° C. for 2 hours while blowing air, and the tetraethoxysilane condensate (A-4) pentaerythritol hexaacrylate (B-1), pentaerythritol tetraacrylate (B- 3) A solution of trimethylolpropane EO 3 mol adduct triacrylate (B-4) was obtained.

Production Example 5 [Production of tetraethoxysilane condensate (A-5) solution]
In a reaction vessel equipped with a stirrer, a cooling pipe, a blowing pipe and a thermometer, 30 parts of dipentaerythritol hexaacrylate (B-1) [trade name: Neomer DA-600, manufactured by Sanyo Chemical Industries, Ltd.] Pentaerythritol EO adduct hexaacrylate (B-5) [trade name: New Frontier MF-001, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.], 30 parts of water, 1.65 parts of water and tetraethoxysilane (a-1) [commodity Name: Dynasylan Silver Condensed, manufactured by Evonik Japan Co., Ltd.] After 40 parts were charged and stirred for 30 minutes, 2.70 parts of paratoluenesulfonic acid was added and reacted at 65 ° C. for 2 hours. Thereafter, the reaction vessel was evacuated and topped at 70 ° C. for 2 hours while blowing air, and the dipentaerythritol hexaacrylate (B-1) and dipentaerythritol EO adduct of tetraethoxysilane condensate (A-5) were added. A solution of hexaacrylate (B-5) was obtained.

Production Example 6 [Production of Tetraethoxysilane Condensate (A-6) Solution]
In a reaction vessel equipped with a stirrer, a cooling tube, a blowing tube, and a thermometer, 20 parts of pentaerythritol tetraacrylate (B-3) [trade name: Neomer EA-300, manufactured by Sanyo Chemical Industries, Ltd.], dipenta Erythritol EO adduct hexaacrylate (B-5) [trade name: New Frontier MF-001, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] 40 parts, water 1.60 parts and tetraethoxysilane (a-1) [trade name : Dynasylan Silver Condensed, manufactured by Evonik Japan Co., Ltd.] After 40 parts were charged and stirred for 30 minutes, 2.70 parts of paratoluenesulfonic acid was added and reacted at 65 ° C. for 2 hours. Then, the reaction vessel was evacuated and topped at 70 ° C. for 2 hours while blowing air, and the pentaerythritol tetraacrylate (B-3) of the tetraethoxysilane condensate (A-6) and dipentaerythritol EO adduct hexa A solution with acrylate (B-5) was obtained.

Production Example 7 [Production of solution of tetraethoxysilane condensate (A-7)]
In a reaction vessel equipped with a stirrer, a cooling tube, a blowing tube and a thermometer, 45 parts of pentaerythritol tetraacrylate (B-3) [trade name: Neomer EA-300, manufactured by Sanyo Chemical Industries, Ltd.], dipenta Erythritol EO adduct hexaacrylate (B-5) [trade name: New Frontier MF-001, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] 40 parts, water 0.60 part and tetraethoxysilane (a-1) [trade name : Dynasylan Silver Condensed, manufactured by Evonik Japan Co., Ltd.] After 15 parts were charged and stirred for 30 minutes, 0.05 parts of paratoluenesulfonic acid was added and reacted at 65 ° C. for 2 hours. Thereafter, the reaction vessel was evacuated and topped at 70 ° C. for 2 hours while blowing air, and the pentaerythritol tetraacrylate (B-3) of the tetraethoxysilane condensate (A-7) and dipentaerythritol EO adduct hexa A solution with acrylate (B-5) was obtained.

Comparative Production Example 1 [Production of Tetraethoxysilane Condensate (A′-1) Solution]
In a reaction vessel equipped with a stirrer, a cooling tube, a blowing tube and a thermometer, 65 parts of phenoxyethyl acrylate (B′-1) [trade name: Light acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.], water 1 . 51 parts and 35 parts of tetraethoxysilane (a-1) [trade name: Dynasylan Silver Condensed, manufactured by Evonik Japan Co., Ltd.] were stirred for 30 minutes, and then 0.05 parts of paratoluenesulfonic acid was charged at 65 ° C. For 2 hours. Thereafter, the reaction vessel was evacuated and topped at 70 ° C. for 2 hours while blowing air to obtain a solution of tetraethoxysilane condensate (A′-1) with phenoxyethyl acrylate (B′-1). This is a metal alkoxide condensate solution for Comparative Example 1 in that monofunctional (B′-1) is used.

In addition, the raw material used in the manufacture example and the comparative manufacture example is as follows.
(A1-1): Tetraethoxysilane [trade name “Dynasylan Silver Condensed”, manufactured by Evonik Japan Co., Ltd.]
(A1-2): Tetra-n-butoxy titanium [trade name “B-1”, manufactured by Nippon Soda Co., Ltd.]
(B-1): p-toluenesulfonic acid [manufactured by Tokyo Chemical Industry Co., Ltd.]
(B-1): Neomer DA-600 [manufactured by Sanyo Chemical Industries, Ltd., the main component is dipentaerythritol hexaacrylate (zero hydroxyl groups), but dipentaerythritol pentaacrylate (one hydroxyl group), dipentaerythritol tetraacrylate (Including 2 hydroxyl groups)]
(B-2): ETERMER 235 [manufactured by Changkou Chemical Co., Ltd., the main component is pentaerythritol triacrylate (one hydroxyl group), but also includes pentaerythritol tetraacrylate (zero hydroxyl group) and pentaerythritol diacrylate (two hydroxyl groups) ]
(B-3): Neomer EA-300 [manufactured by Sanyo Chemical Industries, Ltd., the main component is pentaerythritol tetraacrylate (0 hydroxyl groups), but also includes pentaerythritol triacrylate (1 hydroxyl group). ]
(B-4): Neomer TA-401 [manufactured by Sanyo Chemical Industries, Ltd., the main component is trimethylolpropane EO 3 mol adduct triacrylate (0 hydroxyl groups), but trimethylolpropane EO 3 mol adduct diacrylate (hydroxyl 1 Also included). ]
(B-5): New Frontier MF-001 [Daiichi Kogyo Seiyaku Co., Ltd., main component is dipentaerythritol EO adduct hexaacrylate (hydroxyl group 0), but dipentaerythritol EO adduct pentaacrylate (hydroxyl group 1) Included). ]
(B′-1): Phenoxyethyl acrylate [Brand name: Light acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.]

Example 1
In a reaction vessel equipped with a stirrer, a condenser tube, and a thermometer, 100 parts of a (meth) acrylate (B-1) solution of the tetraethoxysilane condensate (A-1) obtained in Production Example 1 was added. Add 3.0 parts of methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (C-2) [trade name “Irgacure 907”, manufactured by BASF Corp.], and uniformly at 65 ° C. The mixture was mixed and stirred until (D-1) was obtained.

Examples 2-6 and Comparative Examples 1-4
Similarly to Example 1, the components shown in Table 1 were uniformly mixed, and the corresponding photocurable resin compositions (D-2) to (D-6) and (D′-1) to (D′-4) were mixed. Obtained.
In Comparative Examples 3 and 4, (A) is not synthesized in (B) as in the present invention, but commercially available inorganic oxide fine particles (A′-3) are simultaneously (D) and (B). And 30 wt% and 10 wt%, respectively.

The raw materials used in Table 1 are as follows.
(A'-3): Silica fine particles [trade name "Colloidal silica MEK-ST" particle size 10-15 nm MEK 40% solution, manufactured by Nissan Chemical Industries, Ltd.]
(C-1): 1,3,5-trimethylbenzoyldiphenylphosphine oxide [trade name “Lucirin TPO”, manufactured by BASF Corporation]
(C-2): 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one [trade name “Irgacure 907”, manufactured by BASF Corporation]
(C-3): 1-hydroxycyclohexyl phenyl ketone [trade name “Irgacure 184”, manufactured by BASF Corporation]

About the photocurable resin composition and the film obtained by making it harden | cure, performance evaluation was performed with the following method. The evaluation results are shown in Table 1.

<Curing method for cured film>
Each of the photocurable resin compositions (D-1) to (D-6) and (D′-1) to (D′-4) is diluted with methyl ethyl ketone using a disperser to prepare a nonvolatile content of 40%. .
Using a bar coater on one side of a TAC film substrate having a thickness of 40 μm, the film thickness after drying and curing was applied to 7 μm, dried at 70 ° C. for 1 minute, and then irradiated with an ultraviolet irradiation device [model number “VPS / I600 "Fusion UV Systems Co., Ltd. same as below. ] Was irradiated with ultraviolet rays of 300 mJ / cm ^{2 in} a nitrogen atmosphere to prepare a film having a cured film on the surface of the base film.

[Evaluation of pencil hardness]
About the film which has a cured film obtained by said operation, pencil hardness was measured according to JISK-5400.
In this evaluation condition, 3H or more is preferable.

[Evaluation of haze (transparency of film)]
About the film which has the cured film obtained by said operation, based on JIS-K7105, the haze was measured using the total light transmittance measuring apparatus [Brand name "haze-gard dual" BYK gardner Co., Ltd. product]. .

[Measurement of total light transmittance (transparency of composition)]
Place a 100 mm thick silicon rubber with 2 cm square on a 1 mm thick slide glass, pour the composition into the hollowed portion, sandwich it with another slide glass, and fix it at both ends with clips. In accordance with JIS-K7105, the total light transmittance (%) was measured using a total light transmittance measuring device [trade name “haze-gard dual”, manufactured by BYK Gardner Co., Ltd.].
The total light transmittance of the composition of the present invention is required to be 90% or more.

From the result of Table 1, even if the photocurable resin composition of Examples 1-6 of this invention contains a large amount of inorganic substances, the transparency of the composition is not impaired, and the cured product has high hardness. Yes.
On the other hand, the comparative example 1 which uses only a monofunctional acrylate has inferior pencil hardness. The pencil hardness of Comparative Example 2 in which the content of the metal alkoxide condensate (A) is less than 25% by weight is also insufficient. It is a manufacturing method which adds commercially available silica fine particles simultaneously with (A), Comprising: The comparative example 3 containing 30 weight% is inferior in transparency. Therefore, in Comparative Example 4 reduced to an amount (10% by weight) that can ensure transparency, the pencil hardness is insufficient.

  Since the hard coat film having a hard coat film obtained by curing the photocurable resin composition of the present invention is excellent in pencil hardness and transparency, the surface hardness of plastic optical parts such as flat panel displays and touch panels is particularly high. It is suitable for a field having excellent transparency.

Claims (4)

Containing a condensate (A) of a metal alkoxide (a), a polyfunctional acrylate (B), and a photopolymerization initiator (C), the condensate (A) is represented by the following general formula (1), (A) The photocurable resin composition in which the content of (A) is 25 to 80% by weight based on the total weight of ~ (C), and the haze value of the cured product is 1% or less.

[In General Formula (1), R ¹ and R ² each independently have a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or one or more hydroxyl groups of a polyhydric alcohol and (meth) acrylic acid. It represents a residue obtained by removing one hydroxyl group from the ester compound (d). R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a residue obtained by removing a hydroxyl group from an ester compound (d) of a polyhydric alcohol and (meth) acrylic acid, or the following general formula The metal atom-containing organic group represented by (2) is represented, and a plurality of R ³ and R ⁴ may be the same or different. M represents a silicon, titanium or zirconium atom. n is an integer of 2-15. ]
[In General Formula (2), R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an ester compound (d) of a polyhydric alcohol and (meth) acrylic acid. And a plurality of R ⁵ and R ⁶ may be the same or different. M represents a silicon, titanium or zirconium atom. k is an integer of 1-5. ] The photocurable resin composition according to claim 1, wherein the residue obtained by removing the hydroxyl group from the ester compound (d) of polyhydric alcohol and (meth) acrylic acid is an organic group represented by the following general formula (3). .

[In Formula (3), m is an integer of 0-5. ] At least one of R ^{1 to} R ^{4 in} the general formula (1) is an organic group represented by the general formula (3), or at least one of R ^{5 to} R ^{6 in} the general formula (2). The photocurable resin composition according to claim 2, wherein the individual is an organic group represented by the general formula (3). The photocurable resin composition according to claim 1, wherein the total light transmittance of the composition is 90% or more.