JP5994296B2 - Photocurable resin composition, image display device using the same, and method for manufacturing image display device - Google Patents

Description

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

A liquid crystal display device is exemplified as a typical image display device equipped with an image display panel. The liquid crystal display device has a liquid crystal display panel composed of a liquid crystal cell and an optical film such as a polarizing plate attached to both outer surfaces thereof. In this liquid crystal cell, two glass substrates having a thickness of about 1 mm with transparent electrodes and pixel patterns formed on the surface are arranged with a gap of about several microns, and liquid crystal is filled and sealed in the gap. It will be.
The liquid crystal display panel is thin and easily scratched. In particular, in mobile phones, game consoles, digital cameras, in-vehicle applications, etc., a transparent front panel (protective panel) with a certain space in front of the liquid crystal display panel In general, a liquid crystal display device having a structure is provided.

  Furthermore, in recent years, touch panels have been mounted on mobile phones, game machines, digital cameras, in-vehicle parts, and image display devices such as notebook personal computers, desktop personal computers, and personal computer monitors. An image display device equipped with such a touch panel has a laminated structure of a front panel, a touch panel, and a liquid crystal display panel. Air is interposed between the front panel and the touch panel, and between the touch panel and the liquid crystal display panel. Intervene. These airs cause light scattering, resulting in a decrease in contrast and brightness.

Moreover, as a current large-sized liquid crystal display device, the surface of the front polarizing plate of the liquid crystal display device is generally subjected to anti-glare (AG) treatment to reduce reflection. This large-sized liquid crystal display device has no means for shock absorption on the AG-treated surface, and has an impact resistance with a structure as a whole liquid crystal display panel and a set of liquid crystal display devices.
Problems with the large-sized liquid crystal display device with this configuration are that the image looks blurred due to AG processing, the liquid crystal display panel is distorted when touched on the surface, and the stain is difficult to remove due to AG processing. In addition to the tendency to become large, it is conceivable that the impact resistance of the liquid crystal display panel is lowered with the future enlargement of the liquid crystal display panel.

In view of this, it is conceivable that a front plate subjected to anti-reflection (AR) processing is placed in front of the liquid crystal display panel to eliminate the disadvantages caused by AG processing.
In this case, if the space between the front plate and the liquid crystal display panel is air, a decrease in transmittance, a decrease in image quality due to double projection, and the like can be considered. Therefore, it has been proposed to fill the space with a resin or the like. (For example, patent document 1).
On the other hand, a resin for filling a space as described above (for example, a space between the protective panel and the image display unit, a space between the protective panel and the touch panel, and a space between the touch panel and the image display unit) of the image display device. When a thermosetting resin composition is used as the composition, it is restricted by the heat resistant temperature as a constituent member of the image display device. Therefore, the use of a liquid photocurable resin composition as a resin composition for filling the space of the image display device has been studied (for example, Patent Document 2).

JP 2008-83491 A JP 2009-001654 A

However, when the liquid photocurable resin composition described in Patent Document 2 is applied to the above-described uses, the photocurable resin composition is stained under high temperature and high humidity conditions after photocuring. The problem of bleeding out occurs.
An object of the present invention is to provide a photocurable resin composition capable of sufficiently suppressing bleed-out after photocuring, an image display device using the same, and a method for manufacturing the image display device. Is.

The present invention relates to [1] to [8].
[1] (A) a polymer having an ethylenically unsaturated bond in the molecule, (B) a monomer having one ethylenically unsaturated bond in the molecule, (C) a photopolymerization initiator, and (D ) A photocurable resin composition comprising an amine compound represented by the following general formula (1).
(In the general formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 1 to 10, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Or an organic group represented by the following general formula (1-1).
(In general formula (1-1), Ra represents ^a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
[2] The photocurable resin composition according to [1], wherein the component (A) is a urethane oligomer having two or more (meth) acryloyl groups.
[3] The photocurable resin composition according to [1] or [2], further including a thiol compound represented by the following general formula (2) as the component (E).
(In General Formula (2), R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, q represents an integer of 0 to 3, and p represents an integer of 1 to 6. A represents a p-valent organic group.)
[4] The photocurable resin composition according to any one of [1] to [3], which contains substantially no organic solvent and has a viscosity at 25 ° C. of 500 to 5000 mPa · s.
[5] The photocurable resin composition according to any one of [1] to [4], wherein the content of the component (D) is 0.1 to 10% by mass with respect to the photocurable resin composition.
[6] An image display having a laminated structure including an image display unit having an image display unit, a protective panel having a light-shielding unit along the outer peripheral edge, and a resin layer existing between the image display unit and the protective panel. Device for
The image display device, wherein the resin layer is a cured product of the photocurable resin composition according to any one of [1] to [5].
[7] An image having a laminated structure including an image display unit having an image display unit, a touch panel, a protective panel having a light-shielding unit along the outer periphery, and a resin layer existing between the touch panel and the protective panel. A display device,
The image display device, wherein the resin layer is a cured product of the photocurable resin composition according to any one of [1] to [5].
[8] An image display unit or touch panel having an image display unit and a protective panel having a light-shielding unit along the outer periphery are disposed to face each other, and a photocurable resin composition is interposed between the photocurable resin and the photocurable resin. A method for producing an image display device for curing a composition comprising:
A method for producing an image display device, wherein the photocurable resin composition according to any one of [1] to [5] is interposed in the gap, and is cured by irradiating light from at least the protective panel surface side.

  ADVANTAGE OF THE INVENTION According to this invention, the photocurable resin composition which can suppress the bleed-out of a photocurable resin composition can be provided under the high-temperature, high-humidity conditions after photocuring.

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, the photocurable resin composition of the present invention, an image display device using the same, and a method for producing the image display device will be described in detail by embodiments. In addition, this invention is not limited by this embodiment.
In this specification, “(meth) acrylate” means “acrylate” and / or “methacrylate” corresponding thereto. Similarly, “(meth) acryl” means “acryl” and “methacryl” corresponding thereto, and “(meth) acryloyl” means “acryloyl” and / or “methacryloyl” corresponding thereto.

[Photocurable resin composition]
The photocurable resin composition of the present invention comprises (A) a polymer having an ethylenically unsaturated bond in the molecule, (B) a monomer having one ethylenically unsaturated bond in the molecule, (C) A photopolymerization initiator and (D) an amine compound represented by the general formula (1) are included.
Hereinafter, each component will be described.

<(A) component: a polymer having an ethylenically unsaturated bond in the molecule>
(A) As the polymer having an ethylenically unsaturated bond in the molecule, the number of the ethylenically unsaturated bonds is not particularly limited, but those having two or more ethylenically unsaturated bonds in the molecule are preferable, The polymer site is preferably an oligomer. Examples of oligomers having two or more ethylenically unsaturated bonds in the molecule include polyester oligomers having two or more (meth) acryloyl groups, urethane oligomers having two or more (meth) acryloyl groups, and (meth) acryloyl. Examples thereof include butadiene oligomers having two or more groups, isoprene oligomers having two or more (meth) acryloyl groups, polyethylene glycol di (meth) acrylate, and polyprolene glycol di (meth) acrylate. These can be used alone or in combination of two or more.
Among these, a urethane oligomer having two or more ethylenically unsaturated bonds in the molecule is preferable from the viewpoint of improving curability, adhesion, and elongation, and from the viewpoint of reducing the curing shrinkage. Is more preferably a urethane oligomer having two (meth) acryloyl groups.

(Production method 1 of component (A))
(A) The urethane oligomer having two or more (meth) acryloyl groups is, for example, a compound obtained by reacting (a1) a diol compound and (a2) a compound having an isocyanate group (hereinafter referred to as a urethane oligomer). In some cases) can be obtained by reacting a compound for introducing a (meth) acryloyl skeleton.
As a compound for introducing the (meth) acryloyl skeleton, (a3) monohydroxy (meth) acrylate, (a4) monocarboxylic acid having (meth) acryloyl group, and (a5) having (meth) acryloyl group It is preferable to use a monoisocyanate compound.

[(A1) Diol Compound]
(A1) Examples of the diol compound include polyether diols such as polyethylene glycol and polypropylene glycol, polybutadiene diols, polyisoprene diols, hydrogenated polybutadiene diols, hydrogenated polyisoprene diols and other polyolefin diols, polyester diols, polycaprolactone diols, Examples thereof include silicone diol. Among these, polyether diol is preferable from the viewpoint of stress / impact relaxation, transparency, and adhesiveness, and polypropylene glycol is more preferable.

[(A2) Compound having an isocyanate group]
As said (a2) compound which has an isocyanate group, the diisocyanate compound represented by following General formula (3) is mentioned, for example.

(In general formula (3), X represents a divalent organic group.)
Examples of the divalent organic group represented by X in the general formula (3) include, for example, an alkylene group having 1 to 20 carbon atoms; unsubstituted or substituted with a lower alkyl group having 1 to 5 carbon atoms such as a methyl group. Arylene groups such as phenylene group, naphthylene group, xylylene group, diphenylmethane-4,4′-diyl group, diphenylsulfone-4,4′-diyl group; hydrogenated diphenylmethane-4,4′-diyl group, etc. It is done.
Carbon number of an alkylene group becomes like this. More preferably, it is 1-18, More preferably, it is 6-12.

  Examples of the diisocyanates represented by the general formula (3) include diphenylmethane-2,4′-diisocyanate; 3,2′-, 3,3′-, 4,2′-, 4,3′-, 5,2'-, 5,3'-, 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate; 3,2'-, 3,3'-, 4,2'- 4,3'-, 5,2'-, 5,3'-, 6,2'- or 6,3'-diethyldiphenylmethane-2,4'-diisocyanate; 3,2'-, 3,3 ' -, 4,2'-, 4,3'-, 5,2'-, 5,3'-, 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate; diphenylmethane-4 , 4'-diisocyanate; diphenylmethane-3,3'-diisocyanate; diphenylmethane such as diphenylmethane-3,4'-diisocyanate Examples include rumethane diisocyanate compounds and hydrogenated products thereof. The diisocyanates represented by the general formula (3) include diphenyl ether-4,4′-diisocyanate; benzophenone-4,4′-diisocyanate; diphenylsulfone-4,4′-diisocyanate; tolylene-2,4- Diisocyanate; Tolylene diisocyanate such as tolylene-2,6-diisocyanate; m-xylylene diisocyanate; p-xylylene diisocyanate; 1,5-naphthalene diisocyanate; 4,4 ′-[2,2-bis (4-phenoxyphenyl) ) Propane] diisocyanate; aromatic isocyanate compounds. Furthermore, the diisocyanates represented by the general formula (3) include hexamethylene diisocyanate; trimethylhexamethylene diisocyanate such as 2,2,4-trimethylhexamethylene diisocyanate; isophorone diisocyanate; 4,4′-dicyclohexylmethane diisocyanate; Examples include cyclohexane-1,4-diisocyanate; hydrogenated m-xylylene diisocyanate; and aliphatic or alicyclic isocyanates such as lysine diisocyanate. As these diisocyanates, it is preferable to use an aliphatic diisocyanate compound in which X in the general formula (3) is a group having an aliphatic group. These can be used alone or in combination of two or more. Of these, trimethylhexamethylene diisocyanate is more preferably used alone or in combination with the above isocyanates, and trimethylhexamethylene diisocyanate is more preferably used alone. In addition, as a compound which has an isocyanate group, you may use trifunctional or more polyisocyanate with the diisocyanate represented by General formula (3).

  The diisocyanates represented by the general formula (3) may be stabilized with a blocking agent necessary to avoid changes over time. Examples of the blocking agent include hydroxy acrylate, alcohol typified by methanol, phenol, oxime and the like, but there is no particular limitation.

[Blending ratio of (a1) diol compound and (a2) compound having an isocyanate group]
The blending ratio when the above (a1) diol compound and (a2) the compound having an isocyanate group are reacted is the number average molecular weight of the urethane oligomer to be produced, and the end of the urethane oligomer to be produced is a hydroxyl group or an isocyanate group. It is adjusted appropriately depending on whether or not.

When the terminal of the urethane oligomer is an isocyanate group, (a1) a diol compound and (a2) a compound having an isocyanate group so that the ratio of the number of isocyanate groups to the number of hydroxyl groups (isocyanate group / hydroxyl group number) is 1.01 or more. Is preferably adjusted, and from the viewpoint of increasing the number average molecular weight, it is preferably adjusted to less than 2. By setting such a ratio, a urethane oligomer having an isocyanate group at the end can be obtained.
Thus, in the case of the urethane oligomer whose terminal is an isocyanate group, examples of the compound for introducing the (meth) acryloyl skeleton include (a3) monohydroxy (meth) acrylate compound.

On the other hand, when the terminal of the urethane oligomer is a hydroxyl group, it has (a1) a diol compound and (a2) an isocyanate group so that the ratio of the number of hydroxyl groups to the number of isocyanate groups (number of hydroxyl groups / number of isocyanate groups) is 1.01 or more. It is preferable to adjust the blending ratio with the compound, and it is preferable to adjust it to less than 2 from the viewpoint of increasing the number average molecular weight.
Thus, in the case of a urethane oligomer having a terminal hydroxyl group, the compound for introducing the (meth) acryloyl skeleton has (a4) monocarboxylic acids having a (meth) acryloyl group or (a5) a (meth) acryloyl group. By using a compound capable of reacting with a hydroxyl group such as a monoisocyanate compound and reacting these compounds with the hydroxyl group at the terminal of the urethane oligomer, a urethane oligomer having two (meth) acryloyl groups can be obtained.

[(A3) Monohydroxy (meth) acrylate]
Examples of the (a3) monohydroxy (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 1,4-cyclohexanedimethanol. Mono (meth) acrylate, caprolactone or alkylene oxide adduct of each of the above (meth) acrylates, glycerin di (meth) acrylate, trimethylol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) Examples include acrylate, ditrimethylolpropane tri (meth) acrylate, and 2-acryloxyethanol. Of these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate are preferred, 2-hydroxyethyl (meth) acrylate is more preferred, and 2-hydroxyethyl Acrylate is more preferred. These monohydroxy compounds can be used alone or in combination of two or more.

[(A4) Monocarboxylic acids having a (meth) acryloyl group]
(A4) Examples of monocarboxylic acids having a (meth) acryloyl group include (meth) acrylic acid.
[(A5) Monoisocyanate compound having (meth) acryloyl group]
(A5) Examples of the monoisocyanate compound having a (meth) acryloyl group include 2-isocyanate ethyl (meth) acrylate.
A compound obtained by reacting the (a1) diol compound with the (a5) monoisocyanate compound having a (meth) acryloyl group is also a urethane oligomer having two or more (meth) acryloyl groups.

(Production method 2 of component (A))
Moreover, the urethane polymer which has a (meth) acryloyl group can also be manufactured by methods other than the above.
As other methods for producing a urethane polymer having a (meth) acryloyl group, for example, a predetermined amount of (a1) diol compound and (a3) monohydroxy (meth) acrylate are mixed, and the temperature is raised to a predetermined temperature. Then, a predetermined amount of the compound (a2) having an isocyanate group is added to the mixture of the component (a1) and the component (a3) over a predetermined time and reacted.
In addition, (A) the oligomer which has two or more ethylenically unsaturated bonds in a molecule | numerator is a conventionally well-known method using the above-mentioned component, for example, polymerization inhibitors, such as p-methoxyphenol, dibutyltin dilaurate, etc. It can be produced by a method in which the above-described components are reacted in the presence of a catalyst.
Content of (A) component in a photocurable resin composition is 60-95 mass% with respect to the total amount of a photocurable resin composition from a viewpoint which makes flexibility, workability | operativity, and a cure shrinkage rate small. It is preferable that it is 70-90 mass%, and it is especially preferable that it is 75-90 mass%.

(Physical properties of component (A))
In the present invention, the weight average molecular weight of the polymer (A) having two or more ethylenically unsaturated bonds in the molecule is 1,000 to 40,000 from the viewpoints of curability, flexibility, and workability. It is preferably 3,000 to 30,000, more preferably 5,000 to 25,000, and even more preferably 5,000 to 20,000.

In the present specification, the weight average molecular weight of the component (A) is measured by gel permeation chromatography (GPC) and is a value converted using a standard polystyrene calibration curve. The number average molecular weight, the weight average molecular weight, and the degree of dispersion are defined as follows assuming that Ni molecules having a molecular weight Mi exist in the component (A).
(A) Number average molecular weight (Mn)
Mn = Σ (N _i M _i ) / ΣNi = ΣX _i M _i
(X _i = Mole fraction of molecules with molecular weight M _i = N _i / ΣN _i )
(B) Weight average molecular weight (Mw)
Mw = Σ (N _i M _i ² ) / ΣN _i M _i = ΣW _i M _i
(W _i = weight fraction of molecules of molecular weight M _i = N _i M _i / ΣN _i M _i )
(C) Molecular weight distribution (dispersion degree)
Dispersity = Mw / Mn

<(B) component: monomer having one ethylenically unsaturated group in the molecule>
The monomer having one ethylenically unsaturated group in the molecule as component (B) is preferably liquid at normal temperature (25 ° C.), and is represented by the following general formula (4) (meth) Acrylate compounds are preferred.
In formula (4), R ⁵ represents a hydrogen atom or a methyl group, Y represents a C 1-5 alkylene group, R ⁶ represents a hydrogen atom or a monovalent organic group, and r represents 0-10. It is an integer.
Examples of the (meth) acrylate compound represented by the general formula (4) 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, lauryl (meth) acrylate, tridecyl ( (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 1-hydroxypropylene Hydroxyl-containing (meth) acrylates such as (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 1-hydroxybutyl (meth) acrylate; diethylene glycol And polyethylene glycol mono (meth) acrylates such as triethylene glycol; polypropylene glycol mono (meth) acrylates such as dipropylene glycol and tripropylene glycol; polybutylene glycol mono (meth) acrylates such as dibutylene glycol and tributylene glycol; Cyclopentenyloxyethyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentanyloxyethyl acrylate, dicyclopent Nyloxyethyl methacrylate, dicyclopentenyl acrylate, dicyclopentenyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, phenoxyethyl (meth) acrylate, butylphenoxy polyethylene glycol (meth) acrylate, pentylphenoxy polyethylene glycol (meth) Acrylate, hexylphenoxypolyethylene glycol (meth) acrylate, heptylphenoxypolyethyleneglycol (meth) acrylate, octylphenoxypolyethyleneglycol (meth) acrylate, nonylphenoxypolyethyleneglycol (meth) acrylate, decylphenoxypolyethyleneglycol (meth) acrylate, etc. .
From the viewpoint of curing shrinkage and transmittance, R ⁶ in the general formula (4) is more preferably an organic group represented by the following structural formula (5), (6) or general formula (7).
(In the general formula (7), R ⁷ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.)
The dicyclopentenyl acrylate is FA-511A, dicyclopentenyloxyethyl acrylate is FA-512A, dicyclopentenyl acrylate is FA-513A, dicyclopentenyloxyethyl methacrylate is FA-512M, dicyclopentanyl. Methacrylate is commercially available as FA-513M (all manufactured by Hitachi Chemical Co., Ltd.).
In the general formula (4), when R ⁶ is the general formula (7), a compound in which R ⁵ is a hydrogen atom, R ⁷ is a hydrogen atom, and r is 1 is FA-310A (Hitachi). As a compound (trade name) manufactured by Kasei Kogyo Co., Ltd., and R ⁵ is a hydrogen atom, R ⁷ is a nonyl group, and an average value of r is 4, FA-314A (Hitachi Chemical Co., Ltd.) ) And product names) are commercially available.
From the viewpoint of further improving the adhesive strength and reliability, it is preferable to use the compound represented by the general formula (4) and a (meth) acrylamide compound in combination.
Examples of the (meth) acrylamide-based compound include hydroxyl group-containing (meth) acrylamides such as hydroxyethyl (meth) acrylamide; morpholine group-containing (meth) acrylates such as acryloylmorpholine, dimethylacrylamide, isopropylacrylamide, dimethylaminopropylacrylamide, Examples thereof include hydroxyethyl acrylamide (isobornyl acrylate).

In the present invention, the monomer means a monomer having a molecular weight of less than 1,000.
Although the molecular weight of (B) component is not specifically limited, 60-900 are preferable, 80-600 are more preferable, and 100-300 are still more preferable. The molecular weight of the monomer is calculated from the atomic weight of the constituent atoms in the composition formula.
The content of the component (B) in the photocurable resin composition is preferably 1 to 25% by mass with respect to the total amount of the photocurable resin composition from the viewpoint of reducing the curing shrinkage rate. The content is more preferably 15% by mass, and particularly preferably 3 to 10% by mass.

<(C) component: photopolymerization initiator>
Examples of the photopolymerization initiator in the present invention include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), 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-methyl Anthraquinone, 1,2-benzoanthraquinone, 2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy- , 2-diphenylethane-1-one, aromatic ketone compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin compounds such as benzoin, methylbenzoin, and ethylbenzoin, benzoin methyl ether, benzoin Benzoin ether compounds such as ethyl ether, benzoin isobutyl ether, benzoin phenyl ether, ester compounds of β- (acridin-9-yl) acrylic acid, 9-phenylacridine, 9-pyridylacridine, 1,7-diacridinoheptane, etc. Acridine compound, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o -Fluorophenyl) -4,5-diph Phenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di ( p-methoxyphenyl) 5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole 2,4,5-triarylimidazole dimer such as dimer, benzyl, 2,2-diethoxyacetophenone, benzyldimethyl ketal, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) -1-butanone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propane, and the like.

In particular, those that do not color the photocurable 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 Emissions) and a combination thereof are preferred.
In order to produce particularly thick sheets, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine A photopolymerization initiator containing an acyl phosphine oxide compound such as oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is preferable.

  The content of the photopolymerization initiator (C) used in the present invention is preferably 0.5 to 10% by mass, and 0.8 to 7% by mass with respect to the total amount of the photocurable resin composition from the viewpoint of curability. Is more preferable, it is still more preferable that it is 1-4 mass%, and it is especially preferable that it is 1-2 mass%.

<(D) component: amine compound represented by general formula (1)>
The component (D) used in the present invention is a compound represented by the following general formula (1).
(In the general formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 1 to 10, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Or an organic group represented by the following general formula (1-1).
(In general formula (1-1), Ra represents ^a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
Among these, R ² is preferably an organic group represented by the general formula (1-1), and R ¹ is a methyl group from the viewpoint of suppressing bleeding out and yellowing of the photocurable resin composition. R ² is an organic group represented by the general formula (1-1), R ^a is a methyl group, and n is preferably 2 to 8.
Specifically, these compounds of the general formula (1) are bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and bis (2,2,6,6-tetramethyl-4-piperidyl). ) Sebacate, bis (1-ethyl-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) adipate, bis (1, 2,2,6,6-pentamethyl-4-piperidyl) glutarate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) succinate, methyl 1,2,2,6,6-pentamethyl-4 -Piperidyl sebacate, propyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate and the like.
These compounds are commercially available, for example, as TINUVIN 292, TINUVIN 765, and TINUVIN 770 DF (above, manufactured by BASF). These compounds can be used individually by 1 type or in combination of 2 or more types.
The content of the amine compound represented by the general formula (1) which is the component (D) used in the present invention is based on the total amount of the photocurable resin composition from the viewpoints of suppression of bleeding out and suppression of yellowing after curing. 0.1 to 10% by mass is preferable, 0.2 to 5% by mass is more preferable, and 0.3 to 3% by mass is particularly preferable.

<(E) component: Thiol compound represented by general formula (2)>
It is preferable that the photocurable resin composition of this invention contains the compound represented by following General formula (2) as (E) component. Thereby, the sclerosis | hardenability of a light-shielding part can be made more excellent.

(In General Formula (2), R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, q represents an integer of 0 to 3, and p represents an integer of 1 to 6. A represents a p-valent organic group.)
From the viewpoint of the stability of the resin composition, a secondary thiol compound represented by the following general formula (8) in which q = 1, R ³ is a methyl group, and R ⁴ is a hydrogen atom is preferable.

(In the general formula (8), A represents an r-valent organic group, and r represents an integer of 1 to 6.)
Examples of such compounds include 1,4-bis (3-mercaptobutyryloxy) butane, 1,3,5-tris (3-mercaptobutyryloxyethyl) -1,3,5-triazine-2. , 4, 6 (1H, 3H, 5H) -trione, pentaerythritol tetrakis (3-mercaptobutyrate), and the like. These compounds are available from Showa Denko KK as the Karenz MT (registered trademark) series (Karenz MT BD1, Karenz MT NR1, Karenz MT PE1, etc.). These compounds can be used individually by 1 type or in combination of 2 or more types.
The content of the thiol compound represented by the general formula (2) which is the component (E) used in the present invention is based on the total amount of all components in the resin composition from the viewpoint of curability of the light shielding part and wet heat resistance. 1 to 30% by mass is preferable, 3 to 20% by mass is more preferable, and 5 to 15% by mass is particularly preferable.
In addition, when not using the amine compound represented by General formula (1) which is (D) component, and using the thiol compound represented by General formula (2) of (E) component for a photocurable resin composition, Bleed out of the photocurable resin composition under high-temperature and high-humidity conditions after photocuring tends to become remarkable. However, by using the amine compound represented by the general formula (1), even if it contains the thiol compound represented by the general formula (2), the photocurable resin composition under high-temperature and high-humidity conditions after photocuring Bleed out of objects can be suppressed.

A stabilizer etc. can be arbitrarily added to the photocurable resin composition by this invention as needed. The stabilizer is added for the purpose of improving the stability of the photocurable resin composition, and examples thereof include triphenyl phosphite.
Moreover, in this invention, it is preferable that an organic solvent (solvent) is not included substantially from a viewpoint of heat-and-moisture resistance reliability and suppressing the bubble generation in hardened | cured material.
“Substantially” means that the photo-curing resin composition of the present invention is not significantly deteriorated after photo-curing, and the organic solvent is present in a small amount (1% by mass or less) in the photo-curing resin composition. It means that it may be, but preferably it is not contained. Here, the organic solvent is an organic compound that does not have an ethylenically unsaturated group in the molecule, is liquid at 25 ° C., and has a boiling point of 250 ° C. or less at atmospheric pressure.

The viscosity (25 ° C.) of the photocurable resin composition of the present invention is preferably 500 to 5000 mPa · s from the viewpoint of bleeding out and workability when interposed between panels before curing, and 1,000. It is more preferably ˜5,000 mPa · s, and still more preferably 2,000 to 4,000 mPa · s. The viscosity is a value measured at 0.5 rpm from a EHD type rotational viscometer (manufactured by Tokyo Keiki Co., Ltd.) using a 3 ° cone rotor.
The curable resin composition of the present invention is used as a composition for protecting an image display unit.
Moreover, 90% or more is preferable, as for the transmittance | permeability after hardening of curable resin composition, 95% or more is more preferable, and 98% or more is still more preferable. The transmittance is measured by the method described in the examples.

[Image display device]
An image display device according to the present invention includes an image display unit having an image display unit, a protective panel having a light-shielding unit along an outer peripheral edge, and a resin layer existing between the image display unit and the protective panel. In the image display device having a laminated structure, the resin layer is a cured product of the photocurable resin composition.
The image display device of the present invention includes an image display unit having an image display unit, a touch panel, a protective panel having a light-shielding portion along the outer periphery, and a resin layer present between the touch panel and the protective panel. An image display device having a laminated structure including the resin layer, wherein the resin layer is a cured product of the photocurable resin composition.
In this method for manufacturing an image display device, an image display unit or touch panel having an image display unit and a protective panel having a light-shielding unit along the outer periphery are arranged to face each other, and a photocurable resin composition is interposed between the gaps. A method for producing an image display device for curing the photocurable resin composition, wherein the photocurable resin composition is interposed and cured by light irradiation at least from the protective panel surface side. It is.
Next, a liquid crystal display device which is an example of an image display device will be described.

<Liquid crystal display device>
FIG. 1 is a side sectional view schematically showing an embodiment of a liquid crystal display device. 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. 20 includes a resin layer 32 provided on the upper surface of 20 and a transparent protective substrate (protective panel) 40 provided on the surface thereof. The resin layer 32 is comprised from the hardening body of the photocurable resin composition of this invention.

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 the liquid crystal display device. 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 from the resin layer 32 provided on the upper surface, the touch panel 30 provided on the upper surface of the resin layer 32, the resin layer 31 provided on the upper surface of the touch panel 30, and the transparent protective substrate 40 provided on the surface thereof. Composed. The resin layers 31 and 32 are comprised from the hardening body of the photocurable resin composition of this invention.
In the liquid crystal display device of FIG. 2, resin layers are 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 them. 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.
In FIG. 2, when using a protective panel having a light-shielding portion along the outer periphery, it is particularly preferable that at least the resin layer 31 uses the photo-curable resin composition of the present invention.
The light transmittance of the resin layer 31 or 32 is preferably 90% or more, more preferably 95% or more with respect to light rays in the visible light region (wavelength: 380 to 780 nm).

  According to the liquid crystal display device shown in FIGS. 1 and 2, since the cured body of the photocurable resin composition of the present invention is provided as the resin layer 31 or 32, it has impact resistance, has no double image, and is clear and has a contrast. High image quality can be obtained.

The liquid crystal display cell 10 can be made of a liquid crystal material well known in the art. Further, depending on the control method of the liquid crystal material, it is classified into TN (Twisted Nematic) method, STN (Super-twisted nematic) method, VA (Virtual Alignment) method, IPS (In-Place-Switching) method, etc. It may be a liquid crystal display cell using a control method.
As the polarizing plates 20 and 22, a polarizing plate common in this technical field can be used. The surfaces of these polarizing plates 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.
As the touch panel 30, what is generally used in this technical field can be used.
The 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 invention is effective for thick films, and can be suitably used when the 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. Specific examples thereof include inorganic plates such as glass plates and quartz plates, resin plates such as acrylic resin plates and polycarbonate plates, and resin sheets such as thick polyester sheets. When high surface hardness is required, a plate such as glass or acrylic resin is preferable, and a glass plate is more preferable.
The surface of these transparent protective substrates may be subjected to treatments such as antireflection, antifouling, and hard coating. Such surface treatment may be performed on one side of the transparent protective substrate or on both sides. A plurality of transparent protective substrates can be used in combination.
The backlight system 50 typically includes a reflecting unit such as a reflecting plate and an illuminating unit such as a lamp.

The liquid crystal display device of FIG. 1 described above includes a step of interposing the photocurable resin composition of the present invention between the image display unit 1 and the transparent protective substrate (protective panel) 40, and from the protective panel 40 surface side. And a step of forming the resin layer 32 by irradiating with light to cure the photocurable resin composition.
As a method of interposing a photocurable resin composition between the image display unit 1 and the protection panel 40, for example, a photocurable resin composition is applied onto the image display unit 1 or the protection panel 40 using a dispenser. And a method of pasting at a vacuum (reduced pressure) or atmospheric pressure, and a method of casting a photocurable resin composition between the image display unit 1 and the protective panel 40 arranged at a certain interval. . When casting the photocurable resin composition, a dam (frame for preventing the photocurable resin composition from flowing out) may be formed around the image display unit 1 and the protection panel 40. Good.

  In the liquid crystal display device of FIG. 2 described above, the photocurable resin composition of the present invention is interposed between the image display unit 1 and the touch panel 30 and / or between the touch panel 30 and the protective panel 40. And a step of forming the resin layers 32 and 31 by irradiating light from the surface side of the protective panel 40 to cure the photocurable resin composition. Examples of the method for interposing the photocurable resin composition include the same method as in the case of the liquid crystal display device shown in FIG.

The light irradiation, for example, using an ultraviolet irradiation device can be carried out under the conditions of exposure ^{500mJ / cm 2 ~5000mJ / cm 2} . The exposure amount refers to a value obtained by multiplying the illuminance that can be measured by an ultraviolet illuminance meter UV-M02 (receiver: UV-36) manufactured by Oak Co., Ltd., by the irradiation time (seconds). The light source for ultraviolet irradiation may be a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, an LED lamp or the like, but it is preferable to use a high pressure mercury lamp or a metal halide lamp.
In addition, in the case of light irradiation, you may use together irradiation from the protective panel 40 surface side, and irradiation from a side surface.
Moreover, hardening can also be accelerated | stimulated by heating the laminated body containing a photocurable resin composition simultaneously with light irradiation.

  The liquid crystal display device that can be manufactured by using the photocurable resin composition of the present invention has been described above, but the image display that can be manufactured by using the photocurable resin composition of the present invention. The application apparatus is not limited to this, and can be applied to 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.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.
First, production examples of a photocurable resin composition that can be used in an image display device to which the present invention is applied will be described below.
In the following synthesis examples, the weight average molecular weight was measured using gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, and polystyrene was determined as a standard substance. The GPC conditions are shown below.
(GPC conditions)
Measuring instrument: HLC-8320GPC [Tosoh Corporation]
Analytical column: TSKgel SuperMultipore HZ-H (3 linked)
[Tosoh Corporation]
Guard column: TSK guard column SuperMP (HZ) -H [Tosoh Corporation]
Eluent: THF
Measurement temperature: 25 ° C

(Synthesis Example 1: Synthesis of polyurethane acrylate oligomer)
In a reaction vessel equipped with a condenser, a thermometer, a stirrer, a dropping funnel and an air injection tube, 155 parts by mass of polypropylene glycol (molecular weight 2,000), 17.9 parts by mass of 2-hydroxyethyl acrylate, p-as a polymerization inhibitor Taking 0.5 parts by mass of methoxyphenol and 0.05 parts by mass of dibutyltin dilaurate as a catalyst, raising the temperature to 70 ° C. while flowing air, then stirring at 70-75 ° C., 2,2,4-trimethylhexamethylenedi 32.4 parts by weight of isocyanate was added dropwise over 2 hours to carry out the reaction.
When the reaction was completed for 5 hours after completion of the dropwise addition, the reaction was terminated by confirming that the isocyanate had disappeared as a result of IR measurement, and had polypropylene glycol and trimethylhexamethylene diisocyanate as repeating units, with ethylene at both ends. The polyurethane acrylate oligomer (weight average molecular weight 7,000) which has an ionic unsaturated bond was obtained. The average number of ethylenically unsaturated bonds per molecule in this polyurethane acrylate oligomer was 2 (calculated value from the charged amount).

Example 1
80 parts by mass of the polyurethane acrylate oligomer obtained in Synthesis Example 1 containing the component (A) as a main component, 5 parts by mass of FA-314A and 2 parts by mass of acryloylmorpholine as the component (B), and diphenyl- (2, 4,6-trimethylbenzoyl) phosphine oxide (photopolymerization initiator) (LAMBSON, trade name SPEDCURE TPO) 1 part by mass, (D) component TINUVIN 292 (BASF, trade name, bis (1,2, 2,6,6-pentamethyl-4-piperidyl) sebacate (75% by weight) and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate (25% by weight)) 1 part by weight, As component (E), pentaerythritol tetrakis (3-mercaptobutyrate) represented by the following structural formula (9) ) (Secondary thiols) (Showa Denko KK, was weighed tradename Karenz MT (TM) PE1) 5 parts by weight, mixed with stirring, and the photo-curable resin composition was prepared. The evaluation results of this resin composition are shown in Table 1.

[Examples 2 to 7, Comparative Example 1]
Each component was mix | blended with the compounding ratio shown in Table 1, and it carried out similarly to Example 1, and prepared the liquid curable resin composition.
A test method for each resin composition obtained in each example and each comparative example and a transparent sheet obtained by curing the resin composition is shown below.

(Light-shielding part curing width)
The prepared resin composition is dropped onto a 16 cm square glass substrate, and another 16 cm square glass substrate is bonded through a 175 μm spacer so that the film thickness becomes 175 μm. A test piece was obtained by irradiating ultraviolet rays at 2,000 mJ / cm ² using an ultraviolet irradiation device. At this time, one side of the glass substrate on the ultraviolet irradiation side was formed of a black ceramic having a transmittance of 0% of 200 to 800 nm of 8 cm × 16 cm, and placed on the surface on the resin composition side.
The glass on one side of the test piece was peeled off, and the width at which the resin composition in the light shielding part was completely formed into a film was measured with calipers, and this value was taken as the light shielding part cured width.

(Bleed-out resistance)
A transparent substrate in which a resin composition is dropped onto glass, another glass is laminated so as to have a film thickness of 175 μm, and the resin composition is cured by irradiation with an ultraviolet ray irradiation of 2,000 mJ / cm ² through an ultraviolet irradiation device. Was made. The produced transparent substrate was stored under high temperature and high humidity (85 ° C./85%) for 500 hours. After 500 hours, when the cured resin composition does not exude at all from between the glass substrates, the resistance to bleed-out is good (○), and when it exudes, the resistance to bleed-out is low (×) It was.

(Yellowing resistance)
The chromaticity b * before and after storing a transparent substrate produced with bleed-out resistance under high temperature and high humidity (85 ° C./85%) for 500 hours was measured using a spectrophotometer (UV-2400PC manufactured by Shimadzu Corporation). When the produced transparent substrate is stored at a high temperature and high humidity (85 ° C./85%) for 500 hours before and after the difference in chromaticity b * Δb * is 0.5 or less, the yellowing resistance is good (◯). When Δb * is greater than 0.5, yellowing resistance is poor (x).

(Curing shrinkage)
A resin composition is dropped onto a PET film (Toyobo Co., Ltd. A4100, 86 mm × 56 mm × 100 μm), and another similar PET film is bonded through a 175 μm spacer so that the film thickness becomes 175 μm. A transparent sheet in which the resin composition was cured by irradiating ultraviolet rays at 2,000 mJ / cm ² from one PET film side using an irradiation apparatus was produced. The transparent sheet was peeled off from the obtained three-layer laminate (PET film / transparent sheet / PET film), and the specific gravity of the transparent sheet and the resin composition before curing was measured with an electronic hydrometer (Alpha Mirage SD- 200L), and the cure shrinkage was calculated from the following equation.
Curing shrinkage (%) = {(specific gravity of the resin composition after curing−specific gravity of the resin composition before curing) / specific gravity of the resin composition before curing} × 100

(viscosity)
The viscosity of each resin composition obtained in each example and each comparative example was measured with an E-type viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) using a 3 ° cone rotor at 0.5 rpm at 25 ° C. The viscosity was measured.

(Transmittance)
A resin composition is dropped onto a PET film (Toyobo Co., Ltd. A4100, 86 mm × 56 mm × 100 μm), and another similar PET film is bonded through a 175 μm spacer so that the film thickness becomes 175 μm. A transparent sheet in which the resin composition was cured by irradiating ultraviolet rays at 2,000 mJ / cm ² from one PET film side using an irradiation apparatus was produced. Using the two-layer PET as a baseline for transmittance, the transparent sheet was peeled off from the obtained three-layer laminate (PET film / transparent sheet / PET film), and the transmittance of this transparent sheet was measured with a spectrophotometer (Corporation). Shimadzu UV-2400PC) was used for measurement. The transmittance was evaluated when the transmittance was 400 nm.

  The test results of each example and comparative example are summarized in Table 1.

DESCRIPTION OF SYMBOLS 1 Image display unit 10 Liquid crystal display cell 20,22 Polarizing plate 30 Touch panel 31,32 Resin layer 40 Transparent protective substrate (protection panel)
50 Backlight system

Claims (8)

(A) a polymer having an ethylenically unsaturated bond in the molecule;
(B) a monomer having one ethylenically unsaturated bond in the molecule,
(C) a photopolymerization initiator, and (D) an amine compound represented by the following general formula (1),
Furthermore, the photocurable resin composition for image display unit protection containing the thiol compound represented by following General formula (2) as (E) component .

(In General Formula (1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 1 to 10, and R ² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Or an organic group represented by the following general formula (1-1).

(In the general formula (1-1), R ^a represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)

(In General Formula (2), R ³ and R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, q represents an integer of 0 to 3, and p represents an integer of 1 to 6. A represents a p-valent organic group.) The photocurable resin composition for protecting an image display unit according to claim 1, wherein the component (A) is a urethane oligomer having two or more (meth) acryloyl groups. It contains substantially no organic solvent, a viscosity at 25 ° C., the image display unit protective photocurable resin composition according to claim 1 or 2 which is 500~5000mPa · s. Content of (D) component is 0.1-10 mass% with respect to the total amount of a photocurable resin composition, The photocuring for image display unit protection as described in any one of Claims 1-3. Resin composition. (E) Content of a component is 1-30 mass% with respect to the total amount of a photocurable resin composition, The photocurable resin for image display unit protection as described in any one of Claims 1-4. Composition. An image display unit having an image display unit;
A protective panel having a light shielding portion along the outer periphery;
An image display device having a laminated structure including a resin layer present between the image display unit and the protective panel,
The said resin layer is an image display apparatus which is a hardened | cured material of the photocurable resin composition for image display unit protection as described in any one of Claims 1-5. An image display unit having an image display unit;
A touch panel;
A protective panel having a light shielding portion along the outer periphery;
An image display device having a laminated structure including a resin layer present between the touch panel and the protective panel,
The said resin layer is an image display apparatus which is a hardened | cured material of the photocurable resin composition for image display unit protection as described in any one of Claims 1-5. An image display unit or touch panel having an image display unit and a protective panel having a light-shielding unit along the outer periphery are arranged opposite to each other, and the photocurable resin composition is interposed by interposing a photocurable resin composition between these gaps. A method of manufacturing an image display device to be cured,
An image display device in which the photocurable resin composition for protecting an image display unit according to any one of claims 1 to 5 is interposed in the gap, and is cured by light irradiation from at least the protective panel surface side. Production method.