JP2016035026A - Photocurable resin composition, image display device using the same, and method for producing image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocurable resin composition that can be suitably applied for filling a space between a protection panel and an image display unit and others in an image display device, and shows excellent peel strength and dielectric constants when formed into a cured product, and an image display device using the same and a method for producing the image display device.SOLUTION: A photocurable resin composition comprises (A) an isoprene polymer having a (meth) acryloyl group, (B) a copolymer formed with a vinyl compound having an aromatic group and a (meth) acrylic acid alkyl ester, and (D) a photopolymerization initiator.SELECTED DRAWING: None

Description

  The present invention relates to a photocurable resin composition, an image display device using the same, and a method for manufacturing the image display device.

  A liquid crystal display device is illustrated as a typical image display device. A liquid crystal display device is a liquid crystal cell in which liquid crystal is filled and sealed through a gap of about several microns between a glass substrate having a thickness of about 1 mm on which transparent electrodes, pixel patterns and the like are formed. The liquid crystal panel which consists of light sources, such as a pasted polarizing plate and a backlight system, is included.

  The polarizing plate that makes up this liquid crystal panel is thin and easily scratched. Especially in mobile phones, game consoles, digital cameras, and in-vehicle applications, a transparent front plate (protective panel) with a certain space in front of the liquid crystal panel In general, a liquid crystal display device having a structure provided with a) is used.

  Furthermore, in recent years, touch panels have been mounted on mobile phones, game machines, digital cameras, in-vehicle parts, notebook computers, desktop computers, personal computer monitors, large liquid crystal monitors, and the like. Such a liquid crystal display device has a laminated structure in which a protective panel, a touch panel, and a liquid crystal panel are laminated in this order, and a certain space is provided between the protective panel and the touch panel, and between the touch panel and the liquid crystal panel. Exists.

  When only air is present in the space in the liquid crystal display device described above, this space causes light scattering, resulting in a decrease in contrast, brightness, transmittance, etc. A decline can occur.

  As a method of preventing such light scattering, a method of filling an oily material in a space between the protective panel and the liquid crystal panel, and a sheet obtained by copolymerizing an acrylic monomer between the protective panel and the liquid crystal panel are used. There are known methods for interposing them.

  In addition, a plasma display panel (PDP), which is one of flat panel displays (FPD), is provided with a space of about 1 to 5 mm from the PDP in order to prevent cracking of the PDP, and a protective panel made of glass or the like having a thickness of about 3 mm. Is provided on the front surface (viewing surface side).

  Furthermore, as a method for preventing cracking of the display, light scattering, etc., in Patent Documents 1 and 2, the space between the protective panel and the image display unit such as a plasma display panel or a liquid crystal panel, or between the protective panel and the touch panel. And an optical film made of a specific resin in the space between the touch panel and the image display unit (hereinafter collectively referred to as “space between the protective panel and the image display unit”). Proposed.

JP 2004-058376 A JP 2009-024160 A

  However, the oil-like material is difficult to seal to prevent leakage, and may damage the material used for the liquid crystal panel. Furthermore, there is a problem that oil-like material leaks out when the protective panel is broken.

  Further, in the film-like material used in Patent Document 1 or 2, there is no problem of leakage as in the case of using an oil-like material, but it cannot be sufficiently deformed along the shape of the space. There is a problem that voids, bubbles and the like are easily generated in the space.

  Therefore, as a method for solving the above-described problem, a method is conceivable in which a space is filled with a liquid photocurable resin composition and then the composition is cured by light irradiation. However, in the conventional photocurable resin composition, it is difficult to improve both the peel strength and the dielectric constant when the composition is a cured product. In addition, when the peel strength of the cured product is low, the force for closely attaching the protective panel and the image display unit or the like is weakened, and problems such as peeling and cracking may occur. In addition, when the dielectric constant is high, the operation sensitivity of the touch panel may decrease.

  Therefore, the present invention can be suitably applied to fill the space between the protective panel and the image display unit in the image display device, and is photocured excellent in peel strength and dielectric constant when cured. An object of the present invention is to provide a functional resin composition, an image display device using the same, and a method for producing the image display device.

  In order to achieve the above object, the present invention provides a copolymer comprising (A) an isoprene polymer having a (meth) acryloyl group, (B) a vinyl compound having an aromatic group, and a (meth) acrylic acid alkyl ester. A photocurable resin composition containing a polymer and (C) a photopolymerization initiator is provided.

  The photocurable resin composition of the present invention can be suitably applied to fill a space between a protective panel and an image display unit in an image display device, and has a peel strength when cured. Excellent dielectric constant.

  The photocurable resin composition may further contain (D) a compound having an ethylenically unsaturated bond. Thereby, the peel strength when it is set as the cured product can be further improved.

  The photocurable resin composition may further contain (E) a plasticizer. Thereby, while being able to improve the peel strength when it is set as hardened | cured material, a dielectric constant can be reduced more.

  The photocurable resin composition may further contain (F) an oil gelling agent. Thereby, the viscosity of a photocurable resin composition can be adjusted and the peel strength when it is set as hardened | cured material can be improved more.

  Content of the said (A) component is good in it being 10 mass%-90 mass% on the basis of the total amount of a photocurable resin composition. Thereby, while being able to improve the peel strength when it is set as hardened | cured material, a dielectric constant can be reduced more.

  The vinyl compound having an aromatic group may be at least one compound selected from the group consisting of styrene, benzyl acrylate or benzyl methacrylate. Thereby, while being able to improve the peel strength when it is set as hardened | cured material, a dielectric constant can be reduced more.

  The (meth) acrylic acid alkyl ester may be at least one compound selected from the group consisting of lauryl acrylate or isostearyl acrylate. Thereby, while being able to improve the peel strength when it is set as hardened | cured material, a dielectric constant can be reduced more.

  Content of the said (B) component is good in it being 5 mass%-85 mass% on the basis of the total amount of a photocurable resin composition. Thereby, while being able to improve the peel strength when it is set as hardened | cured material, a dielectric constant can be reduced more.

  The present invention also provides an image display device comprising: an image display unit; a protection panel; and a resin layer made of a cured product of the photocurable resin composition, disposed between the image display unit and the protection panel. I will provide a.

  The present invention also provides an image display unit, a protection panel, a touch panel disposed between the image display unit and the protection panel, and between the image display unit and the touch panel, or between the touch panel and the protection panel. And a resin layer made of a cured product of the photocurable resin composition.

  The present invention is also a method of manufacturing an image display device comprising an image display unit, a protection panel, and a resin layer disposed between the image display unit and the protection panel, the image display unit and the protection panel And the step of interposing the photocurable resin composition between the surface and the step of irradiating light from the protective panel surface side and curing the photocurable resin composition to form a resin layer. An apparatus manufacturing method is provided.

  The present invention also provides an image display unit, a protection panel, a touch panel disposed between the image display unit and the protection panel, and between the image display unit and the touch panel, or between the touch panel and the protection panel. A process for interposing the photocurable resin composition between the image display unit and the touch panel, or between the touch panel and the protective panel. And a step of irradiating light from the protective panel surface side to cure the photocurable resin composition to form a resin layer.

  According to the present invention, light that can be suitably applied to fill a space between a protective panel and an image display unit in an image display device, and has excellent peel strength and dielectric constant when cured. A curable resin composition, an image display device using the same, and a method for manufacturing the image display device can be provided.

It is side surface sectional drawing which shows typically one Embodiment of the liquid crystal display device which is an example of the image display apparatus of this invention. It is side surface sectional drawing which shows typically the liquid crystal display device which mounts the touchscreen which is one Embodiment of the liquid crystal display device which is an example of the image display apparatus of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  In this specification, “(meth) acrylate” means “acrylate” or “methacrylate” corresponding thereto. Similarly, “(meth) acryl” means “acryl” or “methacryl” corresponding thereto, and “(meth) acryloyl” means “acryloyl” or “methacryloyl” corresponding thereto.

  The photocurable resin composition of the present embodiment (hereinafter also simply referred to as “resin composition”) is also referred to as an (A) isoprene polymer having a (meth) acryloyl group (hereinafter referred to as “(A) component”). ), (B) a copolymer containing an aromatic group-containing vinyl compound and (meth) acrylic acid alkyl ester (hereinafter also referred to as “component (B)”) and (C) a photopolymerization initiator ( Hereinafter, it is also referred to as “component (C)”.

  The photocurable resin composition of the present embodiment further includes (D) a compound having an ethylenically unsaturated bond (hereinafter, also referred to as “(D) component”), (E) a plasticizer (hereinafter, “ (E) also referred to as “component”) or (F) oil gelling agent (hereinafter also referred to as “component (F)”), preferably containing one or more, and stable as necessary. Other additives such as an agent and a thiol compound can be contained.

[(A) component: isoprene polymer having a (meth) acryloyl group]
(A) As an isoprene polymer which has a (meth) acryloyl group, the compound which has a structural unit represented by the following general formula (I) is preferable, for example.

In the general formula (I), the total number of structural units of the isoprene unit having a (meth) acryloyl group (hereinafter also referred to as “structural unit (I-1)”) is represented by m. In the general formula (I), m is 1 to 5, preferably 1.5 to 4.0, more preferably 2.0 to 3.5, and still more preferably 2.0 to 3.0. . In the general formula (I), R ¹¹ represents a hydrogen atom or a methyl group.

  The component (A) may further contain a structural unit of an isoprene unit having no (meth) acryloyl group (hereinafter also referred to as “structural unit (I-2)”). In the component (A), the total number of structural units (I-2) is represented by n. Although n is 50-1000, Preferably it is 100-800, More preferably, it is 150-700, More preferably, it is 200-600.

  As a commercial item of the compound which has a structural unit represented by the said general formula (I), UC-102, UC-203 (above, Kuraray Co., Ltd. make, brand name) etc. are mentioned.

  The content of the component (A) is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more, based on the total amount of the resin composition. Furthermore, the content of the component (A) is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less, particularly preferably 70% by mass or less, based on the total amount of the resin composition. It is. When the content of the component (A) is in the above range, the peel strength when the cured product is obtained can be further improved, and the dielectric constant can be further reduced.

[(B) component: a copolymer comprising an aromatic group-containing vinyl compound and a (meth) acrylic acid alkyl ester]
Examples of the copolymer (B) using a vinyl compound having an aromatic group and a (meth) acrylic acid alkyl ester include copolymers having structural units represented by the following general formulas (II) and (III). Polymers are preferred. In addition, the copolymer of (B) component may have structural units other than the structural unit represented by general formula (II) and (III).

In component (B), (meth) acrylic acid represented by general formula (II), the total number of structural units derived from vinyl compounds having an aromatic group, represented by x, and represented by general formula (III) The total number of structural units derived from the alkyl ester is indicated by y. In the general formula (II), X represents a monovalent group having an aromatic group, and X is preferably a phenyl group or a benzyl group, and more preferably a phenyl group. In the general formula ^{(III), R 12} represents an alkyl group, the number of carbon atoms is preferably from 4 to 18, more preferably from 5 to 18, more preferably 12 to 18. In the component (B), x is 10 to 90, preferably 15 to 85, and more preferably 20 to 80. y is 10 to 90, preferably 15 to 85, and more preferably 20 to 80.

In the general formula (III), examples of the alkyl group represented by R ¹² include an isostearyl group, a lauryl group, a tridecyl group, an isodecyl group, an isononyl group, an ethylhexyl group, and a butyl group. Among these, preferred are an isostearyl group and a lauryl group, and an isostearyl group is particularly preferred.

  The copolymer having the structural units represented by the general formulas (II) and (III) is obtained by copolymerizing a vinyl compound having an aromatic group and a (meth) acrylic acid alkyl ester by a known method. I can do it.

  Examples of vinyl compounds having an aromatic group include styrene, 4-vinyltoluene, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, naphthalenoxyethyl (meth) acrylate, and phenoxydiethylene glycol (meth) acrylate. Can be mentioned. Among these vinyl compounds, styrene (manufactured by Wako Pure Chemical Industries, Ltd.), FA-BzA (manufactured by Hitachi Chemical Co., Ltd., trade name), FA-BzM (manufactured by Hitachi Chemical Co., Ltd.) are preferable. , Product name) and the like.

  The number of carbon atoms of the alkyl group in the (meth) acrylic acid alkyl ester is preferably 4-18, more preferably 5-18, and particularly preferably 12-18.

  Examples of (meth) acrylic acid alkyl esters include isostearyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, isodecyl (meth) acrylate, isononyl (meth) acrylate, ethylhexyl (meth) acrylate, and butyl acrylate. Etc. Among these, preferred are isostearyl (meth) acrylate and lauryl (meth) acrylate, with isostearyl (meth) acrylate being particularly preferred.

  The content of the component (B) is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, based on the total amount of the resin composition. Furthermore, content of (B) component becomes like this. Preferably it is 85 mass% or less, More preferably, it is 80 mass% or less.

[(C) component: photopolymerization initiator]
A photocurable resin composition contains a photoinitiator as (C) component. Thereby, after forming the physical gel-like substance containing the component (A) and the component (B) into a predetermined shape, the component (A) and the component (B) can be three-dimensionally crosslinked, and leakage is prevented. It can be suppressed more. In this photopolymerization initiator, the curing reaction proceeds by irradiation with active energy rays. Here, active energy rays refer to ultraviolet rays, electron beams, α rays, β rays, γ rays and the like.

  There is no restriction | limiting in particular as a photoinitiator, It is possible to use well-known materials, such as a benzophenone series, anthraquinone series, a benzoyl series, a sulfonium salt, a diazonium salt, and an onium salt.

  Specific examples of the photopolymerization initiator include benzophenone, N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N, N ′, N′-tetraethyl-4. , 4′-diaminobenzophenone, 4-methoxy-4′-dimethylaminobenzophenone, α-hydroxyisobutylphenone, 2-ethylanthraquinone, t-butylanthraquinone, 1,4-dimethylanthraquinone, 1-chloroanthraquinone, 2,3- Dichloroanthraquinone, 3-chloro-2-methylanthraquinone, 1,2-benzoanthraquinone, 2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl Phenyl ketone, 2,2-di Aromatic ketone compounds such as toxi-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-diethoxyacetophenone; benzoin, methylbenzoin, ethyl Benzoin compounds such as benzoin; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether and benzoin phenyl ether; benzyl compounds such as benzyl and benzyldimethyl ketal; β- (acridin-9-yl) (meth) acryl Ester compounds of acids; acridine compounds such as 9-phenylacridine, 9-pyridylacridine, 1,7-diacridinoheptane; 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o -Chloroph Enyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5 -Diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) 5-phenylimidazole dimer, 2- (2, 2,4,5-triarylimidazole dimers such as 4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer; 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 2-methyl-1- [4- (methylthio) phenyl] -2-mol Α-aminoalkylphenone compounds such as lino-1-propanone; acyl phosphine oxide compounds such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; oligo (2-hydroxy-2-methyl- 1- (4- (1-methylvinyl) phenyl) propanone) and the like.

  In particular, photopolymerization initiators that do not color the resin composition include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2- Α-hydroxyalkylphenone compounds such as hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis Acylphosphine oxide compounds such as (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; oligo (2-hydroxy- 2-Methyl-1- (4- (1-methylvinyl) phenyl) propa Down) is preferable, and it is more preferable that a combination of these.

  The content of the component (C) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and 0.3% by mass or more, based on the total amount of the resin composition. More preferably it is. There exists a tendency which can start photopolymerization more favorably as content of (C) component is 0.1 mass% or more. Furthermore, the content of the component (C) is preferably 10% by mass or less, more preferably 8% by mass or less, and further preferably 6% by mass or less. There exists a tendency which can suppress that the hue of the obtained hardened | cured material is yellowish as content of (C) component is 10 mass% or less.

[Component (D): Compound having an ethylenically unsaturated bond]
The photocurable resin composition may contain, as the component (D), a compound having an ethylenically unsaturated bond, and as the compound, (D1) a polymer having an ethylenically unsaturated bond in the molecule, or (D2) A monomer having one ethylenically unsaturated group in the molecule may be included. Hereinafter, the component (D1) and the component (D2) will be described.

<(D1) component: a polymer having an ethylenically unsaturated bond in the molecule>
Examples of the polymer having an ethylenically unsaturated bond in the molecule as the component (D1) include a polyester oligomer having a (meth) acryloyl group, a urethane polymer having a (meth) acryloyl group, and polyethylene glycol mono (meth). Examples include acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol mono (meth) acrylate, polypropylene glycol di (meth) acrylate, and butadiene polymers having a (meth) acryloyl group.

  Among these, a butadiene polymer having a (meth) acryloyl group is preferable from the viewpoint of transparency, yellowing resistance, and balance of various properties.

  The content of the component (D1) in the resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total amount of the resin composition, from the viewpoints of curability, curing shrinkage rate, and elastic modulus. More preferably, it is 15% by mass or more. When the content of the component (D1) is 5% by mass or more, the curability of the resin composition can be further improved, and the wet heat resistance of the cured product tends to be improved. On the other hand, the content of the component (D1) is preferably 45% by mass or less, more preferably 40% by mass or less, still more preferably, based on the total amount of the resin composition, from the viewpoints of curability, curing shrinkage, and elastic modulus. Is 35% by mass or less. When the content of the component (D1) is 45% by mass or less, the curing shrinkage rate is more favorable, and the elastic modulus of the cured product tends not to be too large.

<(D2) component: monomer having one ethylenically unsaturated group in the molecule>
The monomer having one ethylenically unsaturated group in the molecule as component (D2) is preferably liquid at room temperature (25 ° C.), and is an alkyl (IV) represented by the following general formula (IV): (Meth) acrylate (hereinafter also referred to as “(D2-1) component”), and a compound having any of (meth) acryloyl group, alicyclic group, hydroxyl group, ether bond, or amide group in the molecule ( Hereinafter, it is more preferably “(D2-2) component”), which is a compound having any of (meth) acryloyl group, alicyclic group, hydroxyl group, ether bond or amide group in the molecule. More preferably.

In the general formula (IV), R ¹³ represents a hydrogen atom or a methyl group, and R ¹⁴ represents an alkyl group having 4 to 20 carbon atoms. From the viewpoint of imparting more flexibility to the cured product of the resin composition, R ¹⁴ is preferably an alkyl group having 6 to 18 carbon atoms, and more preferably an alkyl group having 8 to 16 carbon atoms.

<(D2-1) component>
Examples of the alkyl (meth) acrylate represented by the general formula (IV) include n-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, n-hexyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, lauryl (Meth) acrylate, tridecyl (meth) acrylate, etc. are mentioned. These compounds may be used alone or in combination of two or more.

<(D2-2) component>
Examples of the compound having any of (meth) acryloyl group, alicyclic group, hydroxyl group, ether bond or amide group in the molecule include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) ) (Meth) acrylates having an alicyclic group such as acrylate, 2-hydroxyethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate 1-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 1-hydroxybutyl (meth) acrylate and the like containing hydroxyl groups ( Me ) Acrylate; hydroxyl-containing (meth) acrylamide such as hydroxyethyl (meth) acrylamide; polyethylene glycol mono (meth) acrylate such as diethylene glycol and triethylene glycol; polypropylene glycol mono (meth) acrylate such as dipropylene glycol and tripropylene glycol; Poly (butylene glycol) mono (meth) acrylates such as dibutylene glycol and tributylene glycol; (meth) acrylates containing morpholine groups such as acryloylmorpholine, dimethylacrylamide, isopropylacrylamide, dimethylaminopropylacrylamide, hydroxyethylacrylamide (isobornyl acrylate) And hindered amine-containing (meth) acrylates. These compounds may be used alone or in combination of two or more.

  Among these, from the viewpoint of heat-and-moisture reliability and workability during application, (meth) acrylate having an alicyclic group, amide group or morpholine group-containing (meth) acrylate is preferable, cyclopentanyl (meth) acrylate, FA-711MM (manufactured by Hitachi Chemical Co., Ltd., trade name), acryloylmorpholine, light acrylate DCP-A (manufactured by Kyoeisha Chemical Co., Ltd., trade name), FA-513AS (manufactured by Hitachi Chemical Co., Ltd., trade name), FA-512M (trade name, manufactured by Hitachi Chemical Co., Ltd.) is more preferable.

  The content of the component (D2) in the resin composition includes the viewpoint of obtaining a resin composition having an appropriate viscosity, the workability, the viewpoint of improving the curability in the light shielding part and the transparency of the cured product, and the curing shrinkage rate. From the viewpoint of adjusting the elastic modulus of the cured product, it is preferably 1% by mass or more, more preferably 5% by mass or more, and further preferably 7% by mass or more, based on the total amount of the resin composition. If the content of the component (D2) is 1% by mass or more, it can be made into a resin composition having a more appropriate viscosity, workability at the time of application can be improved, and the curing shrinkage rate can be increased. There is a tendency to be lower. Furthermore, the curability of the light-shielding part of the obtained resin composition can be made better, and the transparency of the cured product tends to be further improved. The content of the component (D2) in the resin composition is preferably 50% by mass or less, more preferably 45% by mass or less, from the viewpoint of adjusting the curing shrinkage rate and the elastic modulus of the cured product. More preferably, it is 40 mass% or less. When the content of the component (D2) is 50% by mass or less, the curing shrinkage rate and the elastic modulus can be further suppressed from being excessively high, and when used in an image display device, display unevenness is more generated. There is a tendency to be able to suppress.

  In addition, the photocurable resin composition of this embodiment may contain a thermal polymerization initiator that generates radicals by heat. Here, by further applying heat to the cured product obtained by photocuring, polymerization of a trace amount of monomer that cannot be polymerized during photocuring is promoted, and the peel strength of the cured product is improved.

  Examples of the thermal polymerization initiator include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and di (2-ethoxyethyl) peroxy. Dicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, t-hexyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, lauroyl peroxide Organic peroxides such as diacetyl peroxide; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonyl) ), 2,2′-azobis (2,4-dimethylvaleroni Ril), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate), 4,4′-azobis (4-cyanovale) Rick acid), 2,2′-azobis (2-hydroxymethylpropionitrile), 2,2′-azobis [2- (2-imidazolin-2-yl) propane] and the like.

  When the thermal polymerization initiator is contained, the content of the thermal polymerization initiator is preferably 0.01% by mass to 1% by mass based on the total amount of the resin composition.

[(E) component: plasticizer]
The photocurable resin composition may contain a plasticizer as the component (E). The plasticizer used as the component (E) is preferably a component that is substantially liquid at 25 ° C. and has no (meth) acryloyl group.

  Examples of the component (E) include butadiene rubber, isoprene rubber, silicon rubber, styrene butadiene rubber, chloroprene rubber, nitrile rubber, butyl rubber, ethylene propylene rubber, urethane rubber, acrylic rubber, chlorosulfonated polyethylene rubber, fluorine rubber, hydrogen Liquefied nitrile rubber, epichlorohydrin rubber liquid; poly α-olefin such as polybutene; hydrogenated α-olefin oligomer such as hydrogenated polybutene; polyvinyl oligomer such as atactic polypropylene; aromatic oligomer such as biphenyl and triphenyl; Hydrogenated polyene oligomers such as hydrogenated liquid polybutadiene; paraffinic oligomers such as paraffin oil and chlorinated paraffin oil; cycloparaffinic oligomers such as naphthenic oil; dimethyl phthalate and diethyl phthalate , Dibutyl phthalate, di- (2-ethylhexyl) phthalate, di-n-octyl phthalate, diisobutyl phthalate, diheptyl phthalate, diphenyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, di (heptyl, nonyl, undecyl) phthalate Phthalic acid derivatives such as benzyl phthalate, butyl benzyl phthalate, dinonyl phthalate, dicyclohexyl phthalate; isophthalic acid derivatives such as dimethyl isophthalate, di- (2-ethylhexyl) isophthalate, diisooctyl isophthalate; Tetrahydrophthalic acid derivatives such as ethylhexyl) tetrahydrophthalate, di-n-octyltetrahydrophthalate, diisodecyltetrahydrophthalate; Adipic acid derivatives such as butyl adipate, di (2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate; azelaic acid derivatives such as di- (2-ethylhexyl) azelate, diisooctylazelate, di-n-hexylazelate; Sebacic acid derivatives such as di-n-butyl sebacate and di- (2-ethylhexyl) sebacate; maleic acid derivatives such as di-n-butyl malate, dimethyl malate, diethyl maleate and di- (2-ethylhexyl) malate; Fumaric acid derivatives such as n-butyl fumarate and di- (2-ethylhexyl) fumarate; tri- (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisodecyl trimellitate, triisooctyl trimellitate Tate, Trie Trimellitic acid derivatives such as hexyl trimellitate and triisononyl trimellitate; pyromellitic acid derivatives such as tetra- (2-ethylhexyl) pyromellitate and tetra-n-octyl pyromellitate; triethyl citrate and tri-n Citric acid derivatives such as butyl citrate, acetyl triethyl citrate, acetyl tri- (2-ethylhexyl) citrate; monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, di- (2 -Itaconic acid derivatives such as ethyl hexyl) itaconate; oleic acid derivatives such as butyl oleate, glyceryl monooleate, diethylene glycol monooleate; methyl acetyl ricinolate, butyl acetyl ricinolate, glyceryl Ricinoleic acid derivatives such as monoricinoleate and diethylene glycol monoricinoleate; stearic acid derivatives such as n-butyl stearate, glycerin monostearate and diethylene glycol distearate; diethylene glycol monolaurate, diethylene glycol dipelargonate, pentaerythritol fatty acid ester, etc. Other fatty acid derivatives of: triethyl phosphate, tributyl phosphate, tri- (2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris (chloroethyl) phosphate Phosphoric acid derivatives such as diethylene glycol dibenzoate, dipropylene glycol Glycol derivatives such as benzoate, triethylene glycol dibenzoate, triethylene glycol di- (2-ethylbutyrate), triethylene glycol di- (2-ethylhexoate), dibutylmethylene bisthioglycolate; glycerol monoacetate, Examples thereof include glycerin derivatives such as glycerol triacetate and glycerol tributyrate, and epoxy derivatives such as epoxidized soybean oil, epoxyhexahydrophthalate diisodecyl, epoxy triglyceride, epoxidized octyl oleate and epoxidized oleate decyl. These compounds can be used alone or in combination of two or more.

  Among these, from the viewpoints of volatility, viscosity, workability, yellowing resistance, compatibility, and heat resistance, butadiene rubber, isoprene rubber, poly α-olefin, hydrogenated α-olefin oligomer, di- (2-ethylhexyl) Sebacate is preferable, and butadiene rubber, poly α-olefin, and di- (2-ethylhexyl) sebacate are more preferable.

  The content of the component (E) is preferably 5% by mass or more, more preferably 8% by mass or more, still more preferably, based on the total amount of the resin composition, from the viewpoint of adjusting the elastic force of the cured product to an appropriate range. Is 10% by mass or more. From the same viewpoint, the content of the component (E) is preferably 63% by mass or less, more preferably 50% by mass or less, and still more preferably 40% by mass or less.

[(F) component: oil gelling agent]
The photocurable resin composition may contain an oil gelling agent as the component (F).

  As the component (F), hydroxy fatty acid, fatty acid amide, n-lauroyl-L-glutamic acid-α, β-dibutyramide, di-p-methylbenzylidene sorbitol glucitol, 1,3: 2,4-bis-0 -Benzylidene-D-glucitol, 1,3: 2,4-bis-0- (4-methylbenzylidene) -D-sorbitol, bis (2-ethylhexanoato) hydroxyaluminum, and the following general formulas (1) to ( And the compound represented by 12).

In the general formula (1), the total number of structural units represented by (—CF ₂ —) (hereinafter also referred to as “structural unit (1-1)”) is represented by p, and represented by (—CH ₂ —). The total number of structural units (hereinafter, also referred to as “structural unit (1-2)”) is denoted by q. In general formula (1), the polymerization form of p structural units (1-1) and q structural units (1-2) may be either block copolymerization or random copolymerization. p is an integer of 3 to 10, q is an integer of 2 to 6, R ¹ is a saturated hydrocarbon group having 1 to 20 carbon atoms, and X is sulfur or oxygen.
In the general formula (2), R ² is a saturated hydrocarbon group having 1 to 20 carbon atoms, and Y ¹ is a bond or a benzene ring.
In the general formula (3), ^{R 3} is a saturated hydrocarbon group having 1 to 20 carbon atoms, ^{Y 2} is a bond or a benzene ring.
In the general formula ^{(4), R} 4 is a saturated hydrocarbon group having 1 to 20 carbon atoms.
In General Formula (6), R ⁵ and R ⁶ are each independently a saturated hydrocarbon group having 1 to 20 carbon atoms.
In the general formula (7), ^{R 7} is a saturated hydrocarbon group having 1 to 20 carbon atoms.
In the general formula (8), ^{R 8} is a saturated hydrocarbon group having 1 to 20 carbon atoms.
In General Formula (10), R ⁹ and R ¹⁰ are each independently a saturated hydrocarbon group having 1 to 20 carbon atoms.

  These compounds can be used alone or in combination of two or more.

  These oil gelling agents express non-covalent intermolecular interactions such as hydrogen bonds, electrostatic bonds, π-π interactions, van der Waals forces, and are linked to each other to form fibrous bonds. Thereby, at least a part of the photocurable resin composition becomes a physical gel-like substance (hereinafter sometimes referred to as gelation or gel-like) at a room temperature of 25 ° C., and as a result, it is less likely to leak out than liquid. It is presumed that it becomes easier to form a desired shape as compared with a solid. The component (F) is preferably a hydroxy fatty acid from the viewpoints of transparency, workability, and compatibility.

  The content of the component (F) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and 0.3% by mass or more based on the total amount of the resin composition. More preferably it is. There exists a tendency which can fully be gelatinized as content of (F) component is 0.1 mass% or more. On the other hand, the content of the component (F) is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less. When the content of the component (F) is 20% by mass or less, the content of the component (A), the component (B), and the component (C) is relatively increased, and there is a tendency that it can be sufficiently photocured. is there.

[Other additives]
Other additives can be further blended in the photocurable resin composition as long as the effects of the present invention are not impaired.

  Other additives include stabilizers such as triphenyl phosphite, 1,4-bis (3-mercaptobutyryloxy) butane, 1,3,5-tris (3-mercaptobutyloxyethyl) -1,3 , 5-triazine-2,4,6 (1H, 3H, 5H) -trione, thiol compounds such as pentaerythritol tetrakis (3-mercaptobutyrate), and the like.

[Physical properties of photocurable resin composition]
The viscosity at 25 ° C. of the photocurable resin composition is preferably 5.0 × 10 ² mPa · s or more, more preferably 1.0 × 10 ³ mPa · s or more, from the viewpoint of suppression of bleeding out and workability. More preferably, it is 2.0 × 10 ³ mPa · s or more. From the same viewpoint, the viscosity of the photocurable resin composition at 25 ° C. is 5.0 × 10 ⁴ mPa · s or less, more preferably 4.7 × 10 ⁴ mPa · s or less, and still more preferably 4.0 ×. 10 ⁴ mPa · s or less. In addition, the viscosity at 25 degreeC here is the value measured based on JISZ8803, and specifically, the value measured with the B-type viscosity meter (the Toki Sangyo make, TPE-100) is meant. The calibration of the viscometer can be performed based on JIS Z 8809-JS14000.

In addition, even if the exposure amount of active energy rays, such as an ultraviolet-ray, an electron beam, an alpha ray, and a beta ray, is as small as 50 mJ / cm < ² >, a photocurable resin composition can fully advance hardening reaction.

[Physical properties of cured product of photo-curable resin composition]
The adhesion of the photocurable resin composition can be evaluated by, for example, peel strength. When a cured product of the photocurable resin composition is used as a constituent member of an image display device, the peel strength is 0.8 N / in from the viewpoint of suppressing peeling between the protective panel and an adherend such as an image display unit. It is preferably 25 mm or more, and more preferably 1.0 N / 25 mm or more. If the peel strength is 0.8 N / 25 mm or more, it is considered that peeling between the substrates can be suppressed.

  The dielectric constant of 25 ° C. and frequency of 100 kHz of the cured product of the photocurable resin composition is preferably 4. from the viewpoint of reducing noise of the touch panel when used as a constituent member of an image display device having a touch panel function. 0 or less, more preferably 3.8 or less. If the dielectric constant is 4.0 or less, malfunctions when using the touch panel can be suppressed.

[Image display device]
Hereinafter, a liquid crystal display device which is an example of an image display device that can be manufactured using the photocurable resin composition of the present embodiment will be described.

  FIG. 1 is a side sectional view schematically showing an embodiment of a liquid crystal display device which is an example of an image display device of the present invention. The liquid crystal display device shown in FIG. 1 includes an image display unit 1 in which a backlight system 50, a polarizing plate 22, a liquid crystal display cell 10, and a polarizing plate 20 are laminated in this order, and a polarizing plate on the viewing side of the liquid crystal display device. The transparent resin layer 32 provided on the upper surface of 20 and the transparent protective substrate (protective panel) 40 provided on the surface thereof. In addition, the transparent resin layer 32 is comprised from the hardened | cured material of the photocurable resin composition of this embodiment.

  FIG. 2 is a side cross-sectional view schematically showing a liquid crystal display device equipped with a touch panel, which is an embodiment of a liquid crystal display device which is an example of the image display device of the present invention. The liquid crystal display device shown in FIG. 2 includes an image display unit 1 in which a backlight system 50, a polarizing plate 22, a liquid crystal display cell 10, and a polarizing plate 20 are laminated in this order, and a polarizing plate on the viewing side of the liquid crystal display device. 20, a transparent resin layer 32 provided on the top surface, a touch panel 30 provided on the top surface of the transparent resin layer 32, a transparent resin layer 31 provided on the top surface of the touch panel 30, and a transparent protective substrate provided on the surface thereof 40.

  In the liquid crystal display device of FIG. 2, a transparent resin layer is interposed between the image display unit 1 and the touch panel 30 and between the touch panel 30 and the transparent protective substrate 40. It suffices to intervene in at least one of these. When the touch panel is on-cell, the touch panel and the liquid crystal display cell are integrated. As a specific example, the liquid crystal display cell 10 of the liquid crystal display device of FIG. 1 may be replaced with an on-cell.

  Since the liquid crystal display device shown in FIGS. 1 and 2 includes the cured product of the photocurable resin composition of the present embodiment as the transparent resin layer 31 or 32, the liquid crystal display device has impact resistance and has no double image and is clear. A high contrast image can be obtained.

  The liquid crystal display cell 10 can be made of a liquid crystal material well known in the art. Also, depending on the control method of the liquid crystal material, it is classified into TN (Twisted Nematic) method, STN (Super-twisted nematic) method, VA (Vertical Alignment) method, IPS (In-Place-Switching) method, etc. In the form, a liquid crystal display cell using any control method may be used.

  As the polarizing plates 20 and 22, a polarizing plate common in this technical field can be used. The surface of the polarizing plate may be subjected to treatments such as antireflection, antifouling, and hard coat. Such surface treatment may be performed on one side of the polarizing plate or on both sides thereof. Moreover, as the touch panel 30, what is generally used in this technical field can be used.

  The transparent resin layer 31 or 32 can be formed with a thickness of 0.02 mm to 3 mm, for example. In particular, the photocurable resin composition of the present embodiment is easy to form a thick film, and is suitable when the transparent resin layer 31 or 32 having a thickness of 0.1 mm or more is formed.

  As the transparent protective substrate 40, a general optical transparent substrate can be used. Examples of the transparent protective substrate include inorganic plates such as glass plates and quartz plates, resin plates such as acrylic plates and polycarbonate plates, and resin sheets such as thick polyester sheets. Among these, when high surface hardness is required, a glass plate and an acrylic plate are preferable, and a glass plate is more preferable. The surface of the transparent protective substrate 40 may be subjected to treatments such as antireflection, antifouling, and hard coat. Such surface treatment may be performed on one side of the transparent protective substrate or on both sides. Further, the transparent protective substrate can be used in combination of a plurality of substrates.

  Although there is no restriction | limiting in particular in the structure as the backlight system 50, Generally, it is comprised from illumination means, such as reflection means, such as a reflecting plate, and a lamp. As these reflecting means and illuminating means, well-known means / configuration applied in a normal image display device can be applied.

[Method for Manufacturing Image Display Device]
The image display apparatus as shown in FIGS. 1 and 2 using the photocurable resin composition of the present embodiment can be produced by the following method.

  First, an image display apparatus including an image display unit and a protection panel as shown in FIG. 1 interposes the photocurable resin composition of the present embodiment between the image display unit and the protection panel. A step (hereinafter also referred to as “step (1a)”), a step of irradiating light from the protective panel surface side to cure the photocurable resin composition, and forming a transparent resin layer (hereinafter referred to as “step (hereinafter referred to as“ step ”). 2a) ”) and the like.

  In addition, an image display device including an image display unit, a touch panel, and a protection panel as shown in FIG. 2 is provided between the image display unit and the touch panel, or between the touch panel and the protection panel. A step of interposing the photocurable resin composition of the present embodiment (hereinafter also referred to as “step (1b)”), and irradiating light from the protective panel surface side to cure the photocurable resin composition, thereby transparent resin It can be manufactured through a step of forming a layer (hereinafter also referred to as “step (2b)”).

  In the steps (1a) and (1b), as a method of interposing the photocurable resin composition between the image display unit and the protection panel, for example, using a dispenser, the image display unit or the protection panel is placed on the image display unit or the protection panel. A method in which the resin composition is applied and then bonded in a vacuum (reduced pressure) or atmospheric pressure, and a method in which the resin composition is cast between an image display unit and a protective panel arranged at a certain interval. Etc. In addition, when casting a photocurable resin composition, you may form a dam around an image display unit and a protection panel.

The light irradiation in the steps (2a) and (2b) is performed by irradiating active energy rays such as ultraviolet rays, electron beams, α rays, β rays, etc., and can be performed using, for example, an ultraviolet irradiation device. Note that the photocurable resin composition can sufficiently advance the curing reaction even when the exposure amount is as small as 50 mJ / cm ² , for example. Therefore, if the exposure amount is 50 mJ / cm ² or more, the curing reaction can be sufficiently advanced to obtain a cured product. In addition, it is preferable that the upper limit of exposure amount shall be 5.0 * 10 < ³ > mJ / cm < ² > or less. The exposure amount refers to a value obtained by multiplying the illuminance measured by an ultraviolet irradiation device (trade name “UV-M02 (receiver: UV-36)” manufactured by Oak Co., Ltd.) or the like with the irradiation time (seconds). .

  Examples of the light source for ultraviolet irradiation include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, and an LED lamp. Among these, a high pressure mercury lamp and a metal halide lamp are preferable.

  In the case of light irradiation, irradiation from the protective panel surface side and irradiation from the side surface may be used in combination. Moreover, hardening can also be accelerated | stimulated by heating the laminated body containing a photocurable resin composition simultaneously with light irradiation.

  As described above, the liquid crystal display device which is one of the image display devices that can be manufactured by using the photocurable resin composition of the present embodiment has been described. However, the photocurable resin of the present embodiment is described. The image display device that can be manufactured by using the composition is not limited to this. The photocurable resin composition of this embodiment can also be applied to, for example, a plasma display (PDP), a cathode ray tube (CRT), a field emission display (FED), an organic EL display, a 3D display, electronic paper, and the like. is there.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

[Example 1]
In the screw tube, 50 parts by mass of isoprene acrylate (trade name: UC-102, manufactured by Kuraray Co., Ltd.) as the component (A), and styrene-isostearyl acrylate copolymer as the component (B) are prepared by the following copolymer. 50 parts by weight, 2 parts by weight of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (manufactured by BASF, trade name: TPO) as component (C) and put in an oven at 80 ° C. After warming, the mixture was allowed to rotate and revolved to obtain a photocurable resin composition.

[Examples 2 to 18 and Comparative Examples 1 to 6]
The components shown in Tables 1 to 4 were placed in a screw tube at the blending amount (unit: parts by mass) shown in the same table, and after heating in an oven at 80 ° C. in the same manner as in Example 1, the mixture was stirred and rotated. The photocurable resin composition of Examples 2-18 and Comparative Examples 1-6 was obtained.

(Copolymer Production Example 1)
700 g of methyl isobutyl ketone was charged into a 2 L reaction vessel, and heated to the first stage synthesis temperature (125 ° C.) under a nitrogen gas atmosphere and a gauge pressure of 0.30 MPa. At 125 ° C., 280 g of styrene (made by Nippon Oxirane Co., Ltd.), isostearyl acrylate (made by Osaka Organic Chemical Industry Co., Ltd., trade name: ISTA), 420 g, perbutyl O (t-butylperoxy-2-ethylhexanoate, Japanese fat A mixed solution of 42 g manufactured by the company, trade name) and 70 g of methyl isobutyl ketone was dropped into the reaction vessel over 2 hours. After completion of the dropwise addition, the reaction was further carried out at the same temperature for 1 hour, and then a mixed solution of 7 g of perbutyl O and 140 g of methyl isobutyl ketone was dropped into the reaction vessel over 1 hour. After completion of the dropping, 105 g of methyl isobutyl ketone was added, and the reaction was continued for another 2 hours by heating to the second stage synthesis temperature (135 ° C.). After cooling the obtained solution, methyl isobutyl ketone was desolvated under reduced pressure of 90 ° C. and gauge pressure of −0.099 MPa to synthesize a styrene-isostearyl acrylate copolymer.

(Copolymer Production Example 2)
A styrene-lauryl acrylate copolymer was synthesized in the same manner as in Production Example 1 except that isostearyl acrylate in Production Example 1 was changed to lauryl acrylate (trade name: FA-112A, manufactured by Hitachi Chemical Co., Ltd.).

(Copolymer Production Example 3)
A benzyl acrylate-lauryl acrylate copolymer was synthesized in the same manner as in Production Example 1 except that the styrene of Production Example 2 was changed to benzyl acrylate (trade name: FA-BzA, manufactured by Hitachi Chemical Co., Ltd.).

(Measurement of weight average molecular weight and number average molecular weight)
Measurement was carried out under the following instrument measurement conditions, and a standard polystyrene equivalent molecular weight was determined.
Equipment used: Hitachi L6000 high performance liquid chromatography (manufactured by Hitachi, Ltd., trade name)
Column: Gel pack R400, R450 and R400M (manufactured by Hitachi Chemical Co., Ltd., trade name)
Eluent: Tetrahydrofuran Column temperature: 40 ° C
Sample concentration: 0.1 g / 5 ml
Flow rate: 2ml / min
Detector: Hitachi L3350 differential refractometer (manufactured by Hitachi, Ltd., trade name)

When the weight average molecular weight (Mw) and number average molecular weight (Mn) of the copolymers obtained in Production Examples 1 to 3 were measured under the above measurement conditions, the styrene-isostearyl acrylate copolymer obtained in Production Example 1 was measured. The coalescence is Mw 7.7 × 10 ³ and Mn 3.9 × 10 ³ , and the styrene-lauryl acrylate copolymer obtained in Production Example 2 is Mw 8.0 × 10 ³ and Mn 3.4 × 10 ^3. The benzyl acrylate-lauryl acrylate copolymer obtained in Example 3 was Mw 7.5 × 10 ³ and Mn 3.2 × 10 ³ .

[Characteristic evaluation]
About the photocurable resin composition obtained by each Example and the comparative example, and its hardened | cured material, the test shown below was done and each characteristic was evaluated. The results are shown in Tables 1-4.

(Evaluation of peel strength)
A frame-shaped spacer having a space of 80 mm in length and a width of 25 mm and having a thickness of 175 μm is pasted on soda glass having a size of 100 mm in length and width using Nystack (manufactured by Nichiban Co., Ltd.), and the space inside the spacer The photocurable resin composition was applied to the film without gaps. A polyester film (product name: Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.) having a width of 100 mm, a length of 200 mm, and a thickness of 125 μm was laminated thereon. Subsequently, it exposed with the exposure amount of 1.0 * 10 < ³ > mJ / cm < ² > using the exposure machine equipped with the high power metal halide lamp, the photocurable resin composition was hardened, and the sample for evaluation was obtained. Next, using a tensile testing machine (trade name: RTC-1210, manufactured by Orientec Co., Ltd.) at a peeling angle of 180 ° and a peeling speed of 300 mm / min, in the length direction of the cured product of the photocurable resin composition. It peeled off in the direction along and peel strength was measured.

(Evaluation of dielectric constant)
A release PET film (manufactured by Teijin DuPont, trade name: Iupilon A63) is placed on the surface of the glass substrate, and a circular frame (thickness 2 mm, inner diameter 56 mm) made of silicon rubber is placed on the inside of the frame. A photo-curable resin composition was poured into the mixture. Further, the same release PET film as described above was placed thereon, and UV irradiation was performed on each side (exposure amount on one side: 1.0 × 10 ³ mJ / cm ² ) to obtain a molded body. The release PET film and the frame were peeled off from the molded body to obtain a cured film of the photocurable resin composition. The thickness (d) of the cured film was measured using a micrometer (manufactured by Mitutoyo Corporation, product number: 543-285B ID-C112RB). Then, an aluminum plate (thickness 2 mm) having a diameter of 56 mm is attached to one surface of the cured film, a copper foil having a diameter of 36 mm (thickness 80 μm), and a ring-shaped copper having an outer diameter of 54 mm and an inner diameter of 40 mm on the other surface. A foil (thickness 80 μm) was stuck in this order to obtain a measurement sample. The measurement sample is sandwiched between measurement tools “HP16451B” manufactured by Hewlett Packard, and the capacitance (C) is measured using a measuring device “HP4275A” manufactured by Hewlett Packard at 25 ° C. and a frequency of 100 kHz. The dielectric constant ε _r was determined by substituting into the following equation. Here, ε ₀ is the dielectric constant of vacuum.
C = ε ₀ × ε _r × (π × 18 mm × 18 mm) / d

The compounds shown in Tables 1 to 4 are as follows.
UC-102: manufactured by Kuraray Co., Ltd., trade name, isoprene acrylate STC / ISTA: styrene-isostearyl acrylate copolymer STC / LA: styrene-lauryl acrylate copolymer BzA / LA: benzyl acrylate-lauryl acrylate copolymer TPO: BASF Corporation, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide G-1000: Nippon Soda Co., Ltd., hydroxylated hydrogenated polybutadiene at both ends, average molecular weight 1500
FA-711MM: manufactured by Hitachi Chemical Co., Ltd., pentamethylpiperidyl methacrylate DCP-A: manufactured by Kyoeisha Chemical Co., Ltd., trade name “light acrylate DCP-A”, dimethylol-tricyclodecane diacrylate FA-513AS: Hitachi Chemical ( Co., Ltd., dicyclopentanyl acrylate FA-512M: manufactured by Hitachi Chemical Co., Ltd., dicyclopentenyloxyethyl methacrylate ACMO: manufactured by Kojin Film & Chemicals Co., Ltd., acryloylmorpholine FA-222A: manufactured by Hitachi Chemical Co., Ltd. , Diethylene glycol diacrylate RICON-130: manufactured by CARAY VALLEY, low molecular weight liquid polybutadiene

  The cured products of the photocurable resin compositions of Examples 1 to 18 had good peel strength and dielectric constant. For this reason, when this hardened | cured material is used for the structural member of the apparatus for image displays, peeling of a base material can be suppressed. In addition, when a touch panel function is provided, a touch operation can be performed with high sensitivity.

  On the other hand, the cured products of the photocurable resin compositions of Comparative Examples 1 to 6 had a good dielectric constant, but the peel strength was low, and the cured product was used as a constituent member of an image display device. It is considered that the peeling of the film is likely to occur.

  The present inventors speculate that the peel strength was particularly improved in Example 5 as follows. It is known that the adhesive strength needs to have contradictory properties, that is, softness for sufficient adhesion of the interface and hardness due to the cohesive force of the resin. It has been known that when tackifier (tackifier) is added to rubber, both softness and hardness are improved, but the reason has been unknown. However, in recent years, with the progress of nano-level analysis technology, it has been found that tackifiers are not compatible with rubber, but exhibit adhesive strength when forming nano-sized dispersion structures. From the above knowledge, even in the photocurable resin composition of Example 5, the STC / ISTA copolymer, which is presumed to have low compatibility with other materials, has a highly nanodispersed structure when it has a specific composition. As a result, it is assumed that the peel strength has greatly increased.

  The cured product of the photocurable resin composition of the present invention has both high peel strength and low dielectric constant, and is good. For this reason, when it is used as a constituent member of an image display device, the base material is difficult to peel off and a touch operation is easy. In view of the above characteristics, the photocurable resin composition of the present invention is suitable as a constituent member for filling a space between a protective panel and an image display unit in an image display device such as a liquid crystal display device. Can be used for

  DESCRIPTION OF SYMBOLS 1 ... Image display unit, 10 ... Liquid crystal display cell, 20, 22 ... Polarizing plate, 30 ... Touch panel, 31, 32 ... Resin layer, 40 ... Protection panel, 50 ... Backlight system.

Claims (12)

(A) an isoprene polymer having a (meth) acryloyl group,
(B) a copolymer using a vinyl compound having an aromatic group and (meth) acrylic acid alkyl ester, and (C) a photopolymerization initiator,
A photocurable resin composition comprising:   (D) The photocurable resin composition of Claim 1 which further contains the compound which has an ethylenically unsaturated bond.   (E) The photocurable resin composition of Claim 1 or 2 which further contains a plasticizer.   (F) The photocurable resin composition according to any one of claims 1 to 3, further comprising an oil gelling agent.   The photocurable resin composition according to any one of claims 1 to 4, wherein the content of the component (A) is 10% by mass to 90% by mass based on the total amount of the photocurable resin composition. object.   The photocurable resin according to claim 1, wherein the vinyl compound having an aromatic group is at least one compound selected from the group consisting of styrene, benzyl acrylate, and benzyl methacrylate. Composition.   The photocurable resin composition according to any one of claims 1 to 6, wherein the (meth) acrylic acid alkyl ester is at least one compound selected from the group consisting of lauryl acrylate or isostearyl acrylate. .   The photocurable resin composition according to any one of claims 1 to 7, wherein the content of the component (B) is 5% by mass to 85% by mass based on the total amount of the photocurable resin composition. object.   The resin layer which consists of a hardened | cured material of the photocurable resin composition as described in any one of Claims 1-8 arrange | positioned between an image display unit, a protection panel, and an image display unit and a protection panel. An image display device comprising:   The image display unit, the protection panel, the touch panel disposed between the image display unit and the protection panel, the image display unit and the touch panel, or the touch panel and the protection panel. An image display device comprising: a resin layer made of a cured product of the photocurable resin composition according to any one of 1 to 8. An image display device comprising: an image display unit; a protection panel; and a resin layer disposed between the image display unit and the protection panel.
A step of interposing the photocurable resin composition according to any one of claims 1 to 8 between the image display unit and the protective panel;
And a step of irradiating light from the protective panel surface side and curing the photocurable resin composition to form the resin layer. An image display unit, a protection panel, a touch panel disposed between the image display unit and the protection panel, a resin layer disposed between the image display unit and the touch panel, or between the touch panel and the protection panel; A method of manufacturing an image display device comprising:
The step of interposing the photocurable resin composition according to any one of claims 1 to 8 between the image display unit and the touch panel, or between the touch panel and the protective panel,
And a step of irradiating light from the protective panel surface side and curing the photocurable resin composition to form the resin layer.

Images