Active energy ray-curable resin composition, cured product, and optical sheet

Abstract

The present invention provides an active energy ray-curable resin composition, a cured product, and an optical sheet that exhibit high refractive index, high abrasion resistance, and high self-healing properties while suppressing moisture adhesion. The active energy ray-curable resin composition comprises a polymerizable compound (A), a photopolymerization initiator (B), and a leveling agent (C). The active energy ray-curable resin composition is characterized in that the polymerizable compound (A) comprises a polymerizable compound (A1) having an alkylene oxide chain in its structure and a polymerizable compound (A2) having an SP value of 8.88 or less, and the polymerizable compound (A1) is contained such that the content of the alkylene oxide chain in the compound structure is 0.6 mmol / g or greater in the total amount of the composition.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2021-116981 filed in Japan on July 15, 2021, and uses the contents thereof herein. Technical Field

[0002] The present invention relates to an active energy ray-curable resin composition for optical articles, a cured product obtained by curing the composition, and an optical sheet including the cured product. Background Art

[0003] In recent years, with the rapid development of display technology such as liquid crystal display devices, there is an increasing demand for new functions and high quality of sheet-shaped or film-shaped optical members used therein. As an example of such an optical member, there is a prism sheet used as a light-concentrating film for backlights.

[0004] Prism sheets refract backlight through their fine concavo-convex surface structure, thereby increasing the brightness of the front of the display. In recent years, there has been a demand for prism sheets with a higher refractive index to further enhance display brightness, as well as excellent abrasion resistance and self-healing properties.

[0005] For example, Patent Document 1 discloses an active energy ray-curable resin composition for optical articles containing fluorene (meth)acrylate and phenoxybenzyl acrylate, and discloses that a cured product obtained by curing the composition has a high refractive index, excellent scratch resistance, and moderate self-healing properties.

[0006] In addition, Patent Document 2 discloses a resin composition for an optical material comprising a reaction product of a bisphenol A epoxy resin and acrylic acid, phenylphenoxyalkyl (meth)acrylate, a specific monofunctional to difunctional chain (meth)acrylate compound, and a photopolymerization initiator, and discloses that the composition has excellent refractive index, hardness, and recovery properties.

[0007] [Prior art literature]

[0008] [Patent Document]

[0009] [Patent Document 1] International Publication No. 2018 / 070256

[0010] [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-219205 Summary of the Invention

[0011] [Problems to be solved by the invention]

[0012] Recently, there has been a growing demand for prism sheets to be hydrophobic in order to enhance not only the aforementioned high refractive index, abrasion resistance (scratch resistance), and self-healing properties, but also durability in various environments. Conventional prism sheets that lack hydrophobicity are susceptible to moisture adhering to the prism sheet surface due to temperature fluctuations during transportation or at the end of use. This creates water stains after the droplets dry, resulting in reduced yield and reduced prism sheet functionality.

[0013] The present invention aims to provide an optical sheet and a cured product having a high refractive index, high abrasion resistance, and high self-healing properties, while suppressing the adhesion of water by exhibiting a high water contact angle, and an active energy ray-curable resin composition that can be used therefor.

[0014] [Technical means to solve the problem]

[0015] That is, the present invention provides the following inventions.

[0016] (1) An active energy ray-curable resin composition comprising a polymerizable compound (A), a photopolymerization initiator (B), and a leveling agent (C), wherein the polymerizable compound (A) comprises a polymerizable compound (A1) having an alkylene oxide chain in its structure, and a polymerizable compound (A2) having an SP value of 8.88 or less, and the polymerizable compound (A1) is contained so that the content of the alkylene oxide chain in the compound structure is 0.6 mmol / g or more in the total amount of the composition.

[0017] (2) The active energy ray-curable resin composition according to (1), comprising a compound represented by the following formula (a2-1) as the polymerizable compound (A2).

[0018] [Chemistry 1]

[0019]

[0020] (Where R 21 is a hydrogen atom or a methyl group, Q 21 is a single bond or a divalent linking group, R 22 is an alkyl group having 14 to 22 carbon atoms)

[0021] (3) The active energy ray-curable resin composition according to (1) or (2), wherein the polymerizable compound (A1) contains a compound represented by the following formula (a1-1).

[0022] [Chemistry 2]

[0023]

[0024] (In the formula, R1 and R2 each independently represent a hydrogen atom or a methyl group, X1 and X2 each independently represent an alkylene group having 2 or 3 carbon atoms, m and n each independently represent an integer greater than 1, and m+n is greater than 20.)

[0025] (4) The active energy ray-curable resin composition according to any one of (1) to (3), comprising a compound represented by the following formula (a1-2) as the polymerizable compound (A1).

[0026] [Chemistry 3]

[0027]

[0028] (Where R 11 represents a hydrogen atom or a methyl group, X 12 represents an alkylene group having 2 or 3 carbon atoms, and p represents an integer greater than 1.

[0029] (5) The active energy ray-curable resin composition according to any one of (1) to (4), wherein the ratio of the polymerizable compound (A2) in the active energy ray-polymerizable compound (A) is 0.1% by mass to 30% by mass.

[0030] (6) The active energy ray-curable resin composition according to any one of (1) to (5), wherein the ratio of the polymerizable compound (A1) in the active energy ray-polymerizable compound (A) is 30% by mass to 95% by mass.

[0031] (7) A cured product characterized by being a cured product of the active energy ray-curable resin composition according to any one of (1) to (6) and having a refractive index of 1.54 or more.

[0032] (8) An optical sheet comprising a layer comprising the cured product according to (7).

[0033] [Effects of the Invention]

[0034] The cured product and optical sheet obtained by curing the active energy ray-curable resin composition of the present invention, by combining a polymerizable compound having a certain amount or more of alkylene oxide chains in its structure, a hydrophobic polymerizable compound having an SP value of a certain value or less, a photopolymerization initiator, and a leveling agent, not only meet the long-standing requirements of high refractive index, high abrasion resistance, and appropriate self-healing properties, but also exhibit a good water contact angle. Therefore, the active energy ray-curable resin composition of the present invention can be suitably used in various optical applications, such as prism sheets used in displays such as liquid crystal displays, lenticular lens sheets used in stereoscopic photographs and projection screens, Fresnel lens sheets used in condenser lenses for overhead projectors, and diffraction gratings used in color filters. DETAILED DESCRIPTION

[0035] <Active energy ray-polymerizable compounds>

[0036] The active energy ray-curable resin composition of the present invention (hereinafter, sometimes simply referred to as “composition”) contains a polymerizable compound (A), a photopolymerization initiator (B), and a leveling agent (C).

[0037] [Polymerizable compound (A)]

[0038] The polymerizable compound (A) (hereinafter sometimes referred to as "component (A)" or "compound (A)") includes a polymerizable compound (A1) having an alkylene oxide chain in its structure and a polymerizable compound (A2) having an SP value of 8.88 or less.

[0039] (Polymerizable compound (A1))

[0040] The polymerizable compound (A1) (hereinafter sometimes referred to as "component (A1)" or "compound (A1)") is a compound having an alkylene oxide chain in its structure. When compound (A1) contains a certain amount or more of alkylene oxide chains, the wear resistance and self-healing properties of the cured composition are improved.

[0041] As an alkylene oxide chain, as long as it has "-O-(CH2) p -structure" (p is an integer of 1 to 10, preferably an integer of 2 to 5) is not particularly limited, and is preferably an ethylene oxide chain, a propylene oxide chain, a butylene oxide chain, or a combination thereof, more preferably an ethylene oxide chain, a propylene oxide chain, or a combination thereof, and particularly preferably an ethylene oxide chain.

[0042] Component (A1) is a polymerizable compound and has a polymerizable group in its structure that can be polymerized by active energy lines. Examples of polymerizable groups include: (meth)acryloyl, (meth)acrylamide, vinyl, vinyl ether, vinyl ester, maleimide, epoxy, etc. In this specification, the so-called "(meth)acryloyl" and "(meth)acrylamide" are general terms that include acryloyl and methacryloyl, acrylamide and methacrylamide, respectively. In addition, the so-called "(meth)acrylate" is a general term that includes acrylate and methacrylate, respectively.

[0043] Among these, as the polymerizable group, a (meth)acryloyl group is particularly preferred because of its high reactivity upon irradiation with active energy rays.

[0044] Examples of the component (A1) include: alkylene oxide-modified poly(meth)acrylates obtained by reacting (meth)acrylic acid with a polyol having an alkylene oxide group, such as trimethylolpropane ethylene oxide-modified poly(meth)acrylate, trimethylolpropane propylene oxide-modified poly(meth)acrylate, di-trimethylolpropane ethylene oxide-modified poly(meth)acrylate, di-trimethylolpropane propylene oxide-modified poly(meth)acrylate, pentaerythritol ethylene oxide-modified poly(meth)acrylate, pentaerythritol propylene oxide-modified poly(meth)acrylate, dipentaerythritol ethylene oxide-modified poly(meth)acrylate, or tetramethylolmethane ethylene oxide-modified poly(meth)acrylate; Alkylene oxide-modified poly(meth)acrylate oligomers such as alkyl-modified epoxy poly(meth)acrylate, propylene oxide-modified epoxy poly(meth)acrylate, ethylene oxide-modified urethane poly(meth)acrylate, propylene oxide-modified urethane poly(meth)acrylate, ethylene oxide-modified polyester poly(meth)acrylate, and propylene oxide-modified polyester poly(meth)acrylate; (meth)acrylates of alkylene oxide adducts of bisphenols such as di(meth)acrylate of ethylene oxide adduct of bisphenol A, di(meth)acrylate of propylene oxide adduct of bisphenol A, di(meth)acrylate of ethylene oxide adduct of bisphenol F, and di(meth)acrylate of propylene oxide adduct of bisphenol F.

[0045] Moreover, as a preferable compound of (A1) component, the compound represented by following formula (a1-1) is mentioned.

[0046] [Chemistry 4]

[0047]

[0048] In the formula, R1 and R2 independently represent a hydrogen atom or a methyl group, and preferably at least one of them is a hydrogen atom. R1 and R2 may be the same group or different groups.

[0049] X1 and X2 independently represent an alkylene group having 2 or 3 carbon atoms. When the carbon number is 2, the moiety is an ethylene oxide chain, and when the carbon number is 3, the moiety is a propylene oxide chain. X1 and X2 may be the same group or different groups.

[0050] m and n are each independently an integer greater than or equal to 1, and m+n is greater than or equal to 20. Excellent wear resistance and self-healing properties can be achieved by setting m+n to greater than or equal to 20. m+n is preferably 20 to 30, and more preferably 20 to 25.

[0051] When m or n is 2 or more, a plurality of X1 or X2 may be the same or different. From the viewpoint of ease of synthesis, a plurality of X1 or X2 are preferably the same, and particularly preferably all X1 and X2 are the same.

[0052] Moreover, as (A1) component, the compound represented by following formula (a1-2) is also preferable.

[0053] [Chemistry 5]

[0054]

[0055] Where R 11 represents a hydrogen atom or a methyl group, and is preferably a hydrogen atom.

[0056] X 12 represents an alkylene group having 2 or 3 carbon atoms, preferably an ethylene group having 2 carbon atoms. p represents an integer of 1 or greater, preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and further preferably 1 or 2.

[0057] When p is greater than 2, multiple X 12 They can be the same or different, multiple X 12 Preferably, they are all the same.

[0058] The compound represented by formula (a1-2) has a biphenyl structure, and thus contributes to increasing the refractive index of a cured product obtained by curing the composition.

[0059] In the composition of the present invention, component (A1) is contained so that the content of the alkylene oxide chain in the compound structure is 0.6 mmol / g or more of the total composition. The content of the alkylene oxide chain is preferably 0.6 mmol / g to 1.6 mmol / g, more preferably 0.6 mmol / g to 1.2 mmol / g, and even more preferably 0.6 mmol / g to 1.0 mmol / g. By setting the content to 0.6 mmol / g or more, good self-healing properties can be achieved, while by setting the content below the upper limit, a water contact angle can be achieved.

[0060] The content of the component (A1) itself is not particularly limited as long as the above-mentioned alkylene oxide chain content is satisfied, but is preferably 10 to 98% by mass of the total amount of the composition, more preferably 10 to 55% by mass, further preferably 10 to 45% by mass, and particularly preferably 20 to 35% by mass.

[0061] The content of component (A1) is preferably 30 to 99.9% by mass, more preferably 60 to 98% by mass, further preferably 70 to 98% by mass, and particularly preferably 80 to 95% by mass of component (A).

[0062] (Polymerizable compound (A2))

[0063] The polymerizable compound (A2) (hereinafter sometimes referred to as "component (A2)" or "compound (A2)") is a polymerizable compound that does not correspond to the component (A1) and has an SP value of 8.88 or less. By using a compound (A2) having an SP value of 8.88 or less, a high water contact angle can be exhibited on the surface after curing.

[0064] The SP value is one of the parameters indicating the affinity between raw materials. In the present invention, it is calculated by the Fedors method as an index of hydrophobicity.

[0065] Component (A2) is a polymerizable compound having a polymerizable group in its structure that is polymerizable by active energy rays. The polymerizable group can be the same compound as described for component (A1). Component (A2) is preferably a (meth)acrylate having a (meth)acryloyl group.

[0066] When the component (A2) is a (meth)acrylate, a compound represented by the following formula (a2-1) is preferred.

[0067] [Chemistry 6]

[0068]

[0069] Where R 21 It is a hydrogen atom or a methyl group, and is preferably a hydrogen atom.

[0070] Q 21 is a single bond or a divalent linking group. Examples of the divalent linking group include substituted alkylene, substituted arylene, substituted divalent heterocyclic group, substituted alkenylene, or a divalent linking group formed by combining these with -O-, -S-, -CO-, or -CO2-. 22 is an alkyl group, so Q 21 It is preferably not an unsubstituted alkylene group.

[0071] Among them, as Q 21 It is preferably a single bond.

[0072] R 22 is an alkyl group having 14 to 22 carbon atoms. The compound represented by formula (a2-1) is obtained by using 22 The hydrophobic compound having such a relatively long-chain alkyl group, component (A2), has an SP value of 8.88 or less, and can impart a water contact angle to the composition of the present invention.

[0073] R 22 The number of carbon atoms in the carbon atom is preferably 16 to 20, more preferably 18 to 20, and particularly preferably 16.

[0074] R 22 The alkyl group is chain-shaped, and can be a straight-chain alkyl group or a branched-chain alkyl group. The effect of the present invention can be more significantly obtained by being a straight-chain alkyl group, so it is preferred. In the case of a branched-chain alkyl group, the number of carbon atoms in the main chain is preferably 14 or more.

[0075] The content of the component (A2) is preferably 0.1 to 30% by mass, more preferably 0.3 to 20% by mass, further preferably 0.5 to 10% by mass, and particularly preferably 1 to 5% by mass of the component (A).

[0076] (Other polymer compounds)

[0077] Component (A) may contain other polymer compounds other than components (A1) and (A2). As other polymer compounds, monofunctional compounds having one polymerizable group, polyfunctional compounds having two or more such polymerizable groups, and compounds not corresponding to components (A1) to (A2) can be suitably used.

[0078] As the monofunctional compound, for example, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, phenylbenzyl (meth)acrylate, phenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, morpholinyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate can be preferably used. Monofunctional (meth)acrylates include 4-hydroxybutyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, cyclohexylethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate. These monofunctional (meth)acrylates may be used alone or in combination.

[0079] The monofunctional compound preferably has a viscosity of 300 mPa·s or less, more preferably 200 mPa·s or less, at 25°C. Furthermore, its refractive index at 25°C and 589 nm is preferably 1.4 or greater, more preferably 1.5 or greater, and even more preferably 1.55 or greater.

[0080] As the monofunctional compound, phenylbenzyl acrylate represented by the following formula (4) is preferred because it can easily increase the refractive index of the obtained cured product while maintaining the viscosity of the composition appropriately.

[0081] [Chemistry 7]

[0082]

[0083] When the compound represented by formula (4) is used, the content of the compound represented by formula (4) in the active energy ray-polymerizable compound (A) contained in the active energy ray-curable resin composition for an optical article of the present invention is preferably 5% by mass to 30% by mass, more preferably 10% by mass to 20% by mass.

[0084] Examples of the polyfunctional compound include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, tetrabutylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dimethicone di(meth)acrylate, and dimethicone di(meth)acrylate. Multifunctional (meth)acrylates such as cyclopentyl acrylate, glyceryl di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, caprolactone-modified neopentyl glycol hydroxypivalate di(meth)acrylate, tetrabromobisphenol A di(meth)acrylate, hydroxytrimethylolacetaldehyde-modified trimethylolpropane di(meth)acrylate, 1,4-cyclohexanedimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glyceryl tri(meth)acrylate, alkyl-modified dipentaerythritol tri(meth)acrylate, and di-trimethylolpropane tetra(meth)acrylate.

[0085] Furthermore, as the polyfunctional (meth)acrylate, for example, a polyfunctional oligomer having an acryloyl group, such as urethane (meth)acrylate, polyester (meth)acrylate, or epoxy (meth)acrylate, can also be used.

[0086] These monofunctional compounds or polyfunctional compounds may be used alone or in combination of two or more.

[0087] [Photopolymerization initiator (B)]

[0088] The photopolymerization initiator (B) (hereinafter sometimes referred to as "component (B)") is not particularly limited, and various known and commonly used initiators can be used. In the manufacture of articles using the composition of the present invention, active energy rays such as ultraviolet rays often pass through the surface of a transparent substrate serving as a support and are irradiated. Therefore, component (B) is preferably an initiator having light absorption in the long wavelength region, for example, one that exhibits photoinitiation within the ultraviolet light range of 360 nm to 450 nm.

[0089] Examples of the component (B) include benzophenones such as benzophenone, 3,3′-dimethyl-4-methoxybenzophenone, 4,4′-bisdimethylaminobenzophenone, 4,4′-bisdiethylaminobenzophenone, 4,4′-dichlorobenzophenone, Michler’s ketone, and 3,3′,4,4′-tetrakis(tert-butylperoxycarbonyl)benzophenone.

[0090] Xanthones and thioxanthones such as xanthone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, and 2,4-diethylthioxanthone; alcohol ketone ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether;

[0091] α-diketones such as benzil and diacetyl;

[0092] Sulfides such as tetramethylthiuram disulfide and p-toluene disulfide;

[0093] Benzoic acids such as 4-dimethylaminobenzoic acid and ethyl 4-dimethylaminobenzoate;

[0094] 3,3'-Carbonyl-bis(7-diethylamino)coumarin, 1-hydroxycyclohexylphenyl ketone, 2,2'-dimethoxy-1,2-diphenylethane-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2 -Methylpropane-1-one, 4-benzoyl-4′-methyldimethyl sulfide, 2,2′-diethoxyacetophenone, benzyl dimethyl ketal, benzyl-β-methoxyethyl acetal, methyl o-benzoylbenzoate, bis(4-dimethylaminophenyl) ketone, p-dimethylaminoacetophenone, α,α-dichloro-4-phenoxyacetophenone, amyl-4-dimethylaminobenzoate, 2-(o-chlorophenyl)-4,5-diphenylimidazolyl dimer, 2,4-bis-trichloromethyl-6-[bis-(ethoxycarbonylmethyl)amino]phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(4-ethoxy)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-ethoxy)phenyl-s-triazine anthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, etc.

[0095] The component (B) may be used alone or in combination of two or more.

[0096] The amount of component (B) used is not particularly limited. However, from the perspective of easily obtaining appropriate curability or obtaining appropriate wear resistance and self-healing properties of the obtained cured product, the amount is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of component (A).

[0097] [Leveling agent (C)]

[0098] A leveling agent (surface conditioner, hereinafter sometimes referred to as "component (C)") is a component that adjusts the surface condition of the coating film formed from the composition of the present invention. The inclusion of a leveling agent improves the wear resistance after curing. Furthermore, a leveling agent reduces the surface tension of the coating film and improves its wettability. Therefore, the use of a leveling agent results in a state where a water contact angle is not exhibited. In the present invention, this problem is solved by the combined use of component (A2), allowing a water contact angle to be exhibited even when component (C) is used, while also achieving excellent wear resistance and self-healing properties.

[0099] (C) Components include, for example, acrylic leveling agents, silicone leveling agents, fluorine leveling agents, and vinyl leveling agents. These leveling agents may be used alone or in combination of two or more.

[0100] Among these surface conditioners, silicone leveling agents are preferably used from the viewpoint of improving self-healing properties. Examples of the silicone leveling agents include BYK series manufactured by BYK-Chemie Japan.

[0101] The content of (C) is preferably 0.005 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and even more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the component (A).

[0102] The active energy ray-curable resin composition of the present invention may optionally contain other components as additives in addition to the components (A) to (C). The additives are not particularly limited as long as they do not correspond to the components (A) to (C), and examples thereof include photosensitizers, ultraviolet absorbers, antioxidants, silicone additives, fluorine additives, rheology control agents, defoaming agents, mold release agents, silane coupling agents, antistatic agents, antifogging agents, colorants, and inorganic fillers.

[0103] The active energy ray-curable resin composition for an optical article of the present invention may optionally contain a solvent. A low solvent content is preferred because it allows for an active energy ray-curable resin composition for an optical article that is less likely to pollute the working environment. Specifically, the active energy ray-curable resin composition for an optical article of the present invention preferably contains no solvent at a content of 1% by mass or less, and preferably contains substantially no solvent.

[0104] Examples of the photosensitizer include amines, ureas, sulfur-containing compounds, phosphorus-containing compounds, chlorine-containing compounds, nitriles, and other nitrogen-containing compounds.

[0105] Examples of the ultraviolet absorber include triazine derivatives such as 2-[4-{(2-hydroxy-3-dodecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-{(2-hydroxy-3-tridecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine; 2-(2'-xanthenecarboxyl-5'-methylphenyl)benzotriazole; 2-(2'-o-nitrobenzyloxy-5'-methylphenyl)benzotriazole; 2-xanthenecarboxyl-4-dodecyloxybenzophenone; and 2-o-nitrobenzyloxy-4-dodecyloxybenzophenone.

[0106] Examples of the antioxidant include hindered phenol-based antioxidants, hindered amine-based antioxidants, organic sulfur-based antioxidants, and phosphate-based antioxidants.

[0107] Examples of the silicone additive include polyorganosiloxanes having an alkyl group or a phenyl group, such as dimethylpolysiloxane, methylphenylpolysiloxane, cyclic dimethylpolysiloxane, methylhydrogenpolysiloxane, polyether-modified dimethylpolysiloxane copolymers, polyester-modified dimethylpolysiloxane copolymers, fluorine-modified dimethylpolysiloxane copolymers, and amino-modified dimethylpolysiloxane copolymers.

[0108] As inorganic filler (inorganic nanoparticles), preferably a filler with a high refractive index, comprises aluminum oxide, zirconium oxide, titanium dioxide, compounds thereof or mixed oxides thereof, or can enumerate these metal oxides. These inorganic nanoparticles are effective as a means of improving the refractive index of a cured product due to their high refractive index compared to general organic materials, but it is necessary to consider the balance of the intensity or substrate adhesion with the molded product, and as an allocation amount, it is practical to have an inorganic nanoparticle in a range of 20 mass % to 60 mass % relative to the total amount of (A) component and inorganic nanoparticles. In addition, wherein in order to further have both high refractive index and self-healing properties, it is more preferably 30 mass % to 50 mass %.

[0109] The amount of each additive used is not particularly limited as long as its effect is sufficiently exerted and curing by active energy rays is not inhibited, but is preferably 0.05 to 20 parts by mass, particularly preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the composition.

[0110] The composition of the present invention may contain a solvent as needed, but the solvent content is preferably low from the viewpoint of pollution of the working environment. Specifically, the solvent content in the composition is preferably 1% by mass or less.

[0111] The active energy ray-curable resin composition of the present invention preferably has a viscosity of 50 to 5000 mPa·s at 25°C, more preferably 100 to 2000 mPa·s, for ease of coating and molding into desired shapes and thicknesses in various optical applications. In particular, when used in prism sheets, a viscosity of 50 to 800 mPa·s is preferred for ease of uniform coating on the master mold for the prism sheet and for ease of replicating the master mold having a fine concave-convex structure (allowing for faster production lines).

[0112] Furthermore, even if the viscosity is outside the above range, it can be used by adopting a method of controlling the temperature of the composition to adjust the viscosity.

[0113] In order to obtain an active energy ray-curable resin composition for optical articles having a cured product having excellent environmental stability, the acid value of the active energy ray-curable resin composition of the present invention (the number of milligrams of potassium hydroxide required to neutralize the acid components present in 1 g of the sample according to a prescribed method) is preferably 5.0 mgKOH / g or less, and particularly preferably 0 mgKOH / g to 3.0 mgKOH / g.

[0114] <Hardened material>

[0115] The active energy ray-curing resin composition of the present invention can be coated or formed on a substrate according to the intended use, and then irradiated with active energy rays to form a cured product. Examples of active energy rays include electron beams, ultraviolet rays, and visible light. When an electron beam is used as the active energy ray, an electron beam generator such as a Cockcroft-Walton accelerator, a Van de Graaff electron accelerator, a resonant transformer accelerator, an insulating core transformer accelerator, a high-frequency high-voltage accelerator (dynamitron), a linear filament, and a high-frequency type can be used to cure the curable resin composition of the present invention. In addition, when ultraviolet rays are used as the active energy ray, mercury lamps such as ultrahigh-pressure mercury lamps, high-pressure mercury lamps, and low-pressure mercury lamps, xenon lamps, carbon arcs, metal halide lamps, and high-power light-emitting diode-ultraviolet (LED-UV) lamps can be used for irradiation and curing.

[0116] The refractive index of the cured product of the active energy ray-curable resin composition of the present invention is preferably 1.50 or greater, more preferably 1.54 or greater, even more preferably 1.55 or greater, and particularly preferably 1.56 or greater. Due to its high refractive index and suitable scratch resistance, the cured product is suitable for various optical products.

[0117] The hardness of the cured product of the present invention can be appropriately designed depending on the intended use. For example, when used in prism sheets, the elastic modulus at 25°C is preferably 5 MPa to 500 MPa, more preferably 10 MPa to 100 MPa. By setting the elastic modulus within this range, a good balance between mechanical strength and toughness (elongation) is achieved, and the restoring force required for self-healing properties is readily exhibited.

[0118] The elastic modulus is a value obtained by performing dynamic viscoelasticity measurement using "RSAII" manufactured by Rheometric Scientific as a viscoelasticity measuring apparatus under measurement conditions of a heating rate of 3°C / min and a frequency of 3.5 Hz.

[0119] The cured product of the present invention preferably has a glass transition temperature (Tg) of 40°C or lower, more preferably 30°C or lower, and particularly preferably 25°C or lower. This glass transition temperature facilitates achieving both a high refractive index and good self-healing properties. While the lower limit of Tg is not particularly limited, it is preferably 5°C or higher, more preferably 10°C or higher, and particularly preferably 15°C or higher.

[0120] Furthermore, in the present invention, by using the components (A) to (C) or blending them within a preferred range, it is easy to adjust to the above-mentioned Tg range.

[0121] The glass transition temperature is a value obtained by reading the temperature at the peak position of tan δ represented by the ratio of the storage elastic modulus E' to the complex elastic modulus E" obtained in the viscoelasticity measurement as Tg.

[0122] [Optical Sheet]

[0123] The optical sheet of the present invention is an optical sheet comprising a layer containing a cured product of the active energy ray-curable resin composition. The optical sheet comprises a transparent resin film on which a prism or lens containing the cured product is laminated. Specifically, examples thereof include prism sheets used in displays such as liquid crystal displays, lenticular lens sheets used in stereoscopic photographs and projection screens, Fresnel lens sheets used in condenser lenses for overhead projectors, and diffraction gratings used in color filters.

[0124] Examples of methods for producing these optical sheets include the following: after filling a master mold having a fine shape required for various applications with the active energy ray-curable resin composition, a substrate is pressed and laminated onto the filled resin composition in a manner that prevents air from entering, and the resin composition is cured by irradiating the substrate with active energy rays such as ultraviolet rays from the substrate side, followed by release from the master mold. Another example of a continuous production method includes the following: after continuously filling a roll-shaped master mold with the resin composition, a substrate is continuously and closely contacted with the filled resin composition in a manner that prevents air from entering, and the resin composition is cured by irradiating the substrate with active energy rays such as ultraviolet rays from the substrate side, followed by release from the roll-shaped master mold.

[0125] As the substrate for forming the optical sheet, a transparent substrate in the form of a film, sheet, or plate can be used. The material of the substrate can be appropriately selected according to the intended use, and examples thereof include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylic resins such as triacetyl cellulose, polycarbonate resins, and methyl methacrylate copolymers, styrene resins, polysulfone resins, polyethersulfone resins, vinyl chloride resins, and polymethacrylimide resins. Inorganic substrates such as glass substrates can also be used.

[0126] The active energy ray-curable resin composition of the present invention can be suitably applied to prism sheets used in various displays, among various optical sheets. These prism sheets have multiple fine prism-shaped portions on one surface of a sheet-like molded body and are typically disposed on the back side (light source side) of a liquid crystal display element, with the prism surface facing the element.

[0127] The prism sheet is a sheet having a prism layer containing a cured product of the active energy ray-curing resin composition on a transparent film. Regarding the shape of the prism layer, in terms of excellent light focusing and improved brightness, the angle θ of the prism vertex is preferably 70° to 110°, more preferably 75° to 110°, and particularly preferably 80° to 95°.

[0128] The prism pitch is preferably 100 μm or less, and particularly preferably 70 μm or less to prevent moiré patterns on the screen and further improve image resolution. The prism concave-convex height is determined by the angle θ between the prism apex and the prism pitch, and is preferably 50 μm or less. Furthermore, the prism lens sheet thickness is preferably thick for strength, but thin for optically suppressing light absorption. A balance between these factors is preferably between 50 μm and 1000 μm.

[0129] [Example]

[0130] The following examples and comparative examples are provided to further illustrate the present invention. Parts and percentages in the examples are by weight unless otherwise specified. The properties and other characteristics in the examples and comparative examples were measured and evaluated as follows.

[0131] Refractive index

[0132] The refractive index of the resin compositions prepared in Examples and Comparative Examples was measured using a multi-wavelength Abbe refractometer (DR-M2) manufactured by ATAGO Co., Ltd. at a reference wavelength (589 nm). The values ​​in the table represent the refractive index of the formulated compositions.

[0133] Viscosity

[0134] The viscosity of the resin compositions prepared in Examples and Comparative Examples at 25° C. was measured using an E-type viscometer (TV-25, type H) manufactured by Toki Sangyo.

[0135] Self-healing properties

[0136] The resin composition prepared in the examples and comparative examples was filled into a prism master mold having a prism pitch of 50 μm, a prism height of 25 μm, and a vertex angle of 90°, and a 125 μm PET film was overlapped and laminated with a roller while applying pressure. The mold was then illuminated from the PET film side with a high-pressure mercury lamp at a cumulative light intensity of 400 mJ / cm 2 The resin composition was cured by irradiation with an amount of irradiation to produce a prism sheet. The obtained prism sheet was scratched with an awl for about 3 cm, and the time until the scratch (line) appeared disappeared was visually observed and evaluated according to the following criteria.

[0137] 5: Instant recovery (scar disappears)

[0138] 4: Recovery within 10 seconds (scar disappears)

[0139] 3: Recovery within 1 minute (scar disappears)

[0140] 2: Recovery within 5 minutes (scar disappears)

[0141] 1: Recovery takes more than 15 minutes (the scar disappears)

[0142] 0: Not restored

[0143] Wear resistance

[0144] A diffuser film cut into a 1cm diameter circle was placed on the prism sheet obtained in the same manner as above. A 400g load was applied and the sheet was rubbed back and forth 40 times over a distance of 10cm using an abrasion tester (IMC-15FA, manufactured by Imoto Manufacturing Co., Ltd.). The surface was evaluated for stripe-shaped scratches based on the area of ​​the scratched area. The evaluation was conducted indoors at 23°C and judged according to the following criteria; scores of A or higher were considered acceptable.

[0145] A: The area of ​​the scar is 5cm 2 the following

[0146] B: The scar area is larger than 5cm 2 and 7cm 2 the following

[0147] C: The scar area is larger than 7cm 2

[0148] Water contact angle

[0149] 50 μl of ion-exchanged water was injected from a syringe onto the prism sheet obtained in the same manner as above. The water contact angle was measured using a water contact angle meter (DMo-501) manufactured by Kyowa Interface Science. The evaluation was conducted indoors at 23°C, with observation parallel to the ridgeline of the prism sheet. The results were evaluated as follows. A score of B or higher was considered acceptable.

[0150] A: The water contact angle after 1 second of dripping is 50° or more, and the water contact angle retention rate after 5 minutes is 80% or more.

[0151] B: The water contact angle after 1 second of dripping is 50° or more and the water contact angle retention rate after 5 minutes is less than 80%

[0152] C: The water contact angle after dripping for 1 second is 30° or more and less than 50°, and the water contact angle retention rate after 5 minutes is 80% or more

[0153] D: The water contact angle after 1 second of dripping is 30° or more and less than 50°, and the water contact angle retention rate after 5 minutes is less than 80%

[0154] E: The water contact angle after dripping for 1 second is less than 30°

[0155] (Examples 1 to 4, Comparative Examples 1 to 5)

[0156] The compounds were melt-mixed according to the formulation shown in the following table to adjust a resin composition. The alkylene oxide content (mmol / g) of the polymerizable compound (A1) is described in the table as "alkylene oxide content".

[0157] The above evaluation was performed using the obtained resin composition. The values ​​of the composition blending amounts in the table are in mass %.

[0158] [Table 1]

[0159]

[0160] [Table 2]

[0161]

[0162] The compounds described in the above table are as follows.

[0163] A1-1: Ethylene oxide-modified bisphenol A diacrylate ("MIRAMER M-2200" manufactured by MIWON Corporation; in the formula (a1-1), R1 and R2 are hydrogen atoms, X1 and X2 are ethylene groups, and m+n=20. The amount of ethylene oxide modification is 20 mol.

[0164] A1-2: Ethylene oxide-modified bisphenol A diacrylate ("MIRAMER M-2100" manufactured by MIWON Corporation; in the formula (a1-1), R1 and R2 are hydrogen atoms, X1 and X2 are ethylene groups, and m+n=10; the amount of ethylene oxide modification is 10 mol)

[0165] A1-3: O-phenylphenol ethylene oxide-modified acrylate ("MIRAMER M-1142" manufactured by MIWON Corporation), wherein R 11 is a hydrogen atom, X 12 is ethylene, p=1, and the amount of ethylene oxide modification is 1 mol)

[0166] A2-1: Stearyl acrylate (SP value: 8.80) ("KOMERATE A189" manufactured by KPX Corporation), wherein R 21 is a hydrogen atom, Q 21 is a single bond, R 22 is a straight-chain compound with 18 carbon atoms)

[0167] A2-2: Cetyl acrylate (SP value: 8.83) ("KOMERATE A169" manufactured by KPX Corporation), wherein R 21 is a hydrogen atom, Q 21 is a single bond, R 22 is a straight-chain compound with 16 carbon atoms)

[0168] A2-3: Lauryl acrylate (SP value: 8.89) ("KOMERATE A129" manufactured by KPX Corporation), wherein R 21 is a hydrogen atom, Q 21 is a single bond, R 22 is a straight-chain compound with 12 carbon atoms)

[0169] A2-4: Behenyl acrylate (SP value: 8.77) ("KOMERATE A229" manufactured by KPX Corporation), wherein R 21 is a hydrogen atom, Q 21 is a single bond, R 22 is a straight-chain compound with 22 carbon atoms)

[0170] A2-5: Stearyl methacrylate (SP value: 8.74) ("KOMERATE A189M" manufactured by KPX Corporation, wherein R 21 is methyl, Q 21 is a single bond, R 22 is a straight-chain compound with 18 carbon atoms)

[0171] A2-6: Isobornyl acrylate (SP value: 9.93) ("IBXA" manufactured by Osaka Organic Chemical Industry Co., Ltd., wherein R 21 is a hydrogen atom, equivalent to R 22 or Q 21 a compound in which the moiety is isobornyl)

[0172] A2-7: tricyclodecane dimethanol diacrylate (SP value: 11.30) ("KOMERATE D0013" manufactured by KPX Corporation, wherein R 21 is a hydrogen atom, equivalent to R 22 or Q 21 a compound having a tricyclodecane skeleton including a monoacrylate)

[0173] A2-8: Cyclohexyl acrylate (SP value: 10.04) ("VISCOTE #155" manufactured by Osaka Organic Chemical Industry Co., Ltd.), wherein R 21 is a hydrogen atom, equivalent to R 22 or Q 21 a compound in which the moiety is a cyclohexyl group)

[0174] B1: 1-Hydroxycyclohexylphenylketone ("OMNIRAD 184" manufactured by IGM RESINS BV)

[0175] C1: Polyether-modified polydimethylsiloxane ("BYK-333" manufactured by BYK-Chemie Japan)

[0176] As is clear from the above results, it was confirmed that the active energy ray-curable resin composition of the present invention has an excellent balance between the development of the water contact angle and the self-healing property or the wear resistance.

[0177] On the other hand, it was confirmed that Comparative Example 1 having an alkylene oxide content of less than 0.6 mmol / g had poor self-healing properties and abrasion resistance. Comparative Examples 2 to 5 containing no polymerizable compound having an SP value of 8.88 or less did not exhibit water contact angles and could not suppress water adhesion.

[0178] [Industrial Applicability]

[0179] As described above, the active energy ray-curable resin composition of the present invention can be suitably used for various optical members including prism sheets.

Claims

1. An active energy ray-curable resin composition comprising a polymerizable compound (A), a photopolymerization initiator (B), and a leveling agent (C), wherein the active energy ray-curable resin composition is characterized in that: The polymerizable compound (A) contains a polymerizable compound (A1) having an alkylene oxide chain in its structure, and a polymerizable compound (A2) having an SP value of 8.88 or less. The polymerizable compound (A1) is contained so that the content of the alkylene oxide chain in the compound structure becomes 6.0 mmol / g or more in the total amount of the composition. Containing a compound represented by the following formula (a1-1) as the polymerizable compound (A1), wherein R1 and R2 are each independently a hydrogen atom or a methyl group, X1 and X2 are each independently an alkylene group having 2 or 3 carbon atoms, m and n are each independently an integer greater than 1, and m+n is greater than 20, or Containing a compound represented by the following formula (a1-2) as the polymerizable compound (A1), Where R 11 represents a hydrogen atom or a methyl group, X 12 represents an alkylene group having 2 or 3 carbon atoms, and p represents an integer greater than 1, The ratio of the polymerizable compound (A2) in the active energy ray polymerizable compound (A) is 0.1% by mass to 30% by mass, and The ratio of the polymerizable compound (A1) in the active energy ray-polymerizable compound (A) is 30% by mass to 95% by mass.

2. The active energy ray-curable resin composition according to claim 1, comprising a compound represented by the following formula (a2-1) as the polymerizable compound (A2), Where R 21 is a hydrogen atom or a methyl group, Q 21 is a single bond or a divalent linking group, R 22 It is an alkyl group having 14 to 22 carbon atoms.

3. A hardened product, characterized in that: A cured product of the active energy ray-curable resin composition according to claim 1 or 2, having a refractive index of 1.54 or greater. 4 . An optical sheet comprising a layer comprising the cured product according to claim 3 .

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