JP6625534B2 - UV curable adhesive composition for touch panel and article - Google Patents

Description

  The present invention relates to an ultraviolet-curable adhesive composition for a touch panel for bonding at least two optical substrates, and a method for producing an optical member using the same.

  In recent years, display devices that allow a touch panel to be attached to a display screen of a display device such as a liquid crystal display, a plasma display, and an organic EL display to enable screen input have been widely used. In this touch panel, a glass plate or a resin film on which a transparent electrode is formed is bonded facing each other with a slight gap, and if necessary, a transparent protective glass or resin film is formed on the touch surface. It has a structure in which boards are bonded together.

  There is a technique using a double-sided pressure-sensitive adhesive sheet for bonding a glass plate or film on which a transparent electrode is formed in a touch panel and a transparent protective plate made of glass or resin, or bonding a touch panel and a display unit. However, using a double-sided pressure-sensitive adhesive sheet has a problem that air bubbles are likely to enter. As a technology that can replace the double-sided pressure-sensitive adhesive sheet, a technology of bonding with a flexible ultraviolet-curable adhesive composition has been proposed.

  On the other hand, when the touch panel and the display unit are bonded with an ultraviolet-curable adhesive, there is a problem that the adhesive strength to the adherend itself is insufficient, and peeling occurs at the interface between the base material and the adhesive. In addition, there is a problem that the adhesive is insufficiently tough and thus cohesively peels off. Further, a strip-shaped light shielding portion is formed on the outermost edge of the transparent protective plate in order to improve the contrast of the displayed image. When the transparent protective plate on which the light-shielding portion is formed is bonded with an ultraviolet-curable adhesive composition, sufficient ultraviolet light does not reach the light-shielding region of the ultraviolet-curable resin that is shaded by the light-shielding portion by the light-shielding portion. As a result, the curing of the resin becomes insufficient. If the curing of the resin is insufficient, problems such as display unevenness near the light-shielding portion occur.

  As a technique for improving the adhesive strength of the adhesive, use of a highly flexible material has been attempted, but a material capable of effectively improving both cohesive peeling and interfacial peeling has not yet been developed.

  On the other hand, as a technique for improving the curing of the resin in the light-shielding region, Patent Literature 1 discloses a technique in which an organic peroxide is contained in an ultraviolet-curable resin, and the resin in the light-shielding portion is cured by heating after irradiation with ultraviolet light. It has been disclosed. However, there is a concern that the heating step may damage the liquid crystal display device and the like. Further, there is a problem that the productivity is poor because a heating step of usually 60 minutes or more is required to bring the resin into a sufficiently cured state. Further, Patent Literature 2 discloses a technique of irradiating an ultraviolet ray from an outer side surface of a surface on which a light shielding portion is formed to cure a resin of the light shielding portion. However, it is difficult to irradiate ultraviolet rays from the side depending on the shape of the liquid crystal display device, so that the method is limited. Further, Patent Document 3 discloses a technique using the slow-acting property of a cationically polymerizable ultraviolet-curable resin, but the resin after curing is inferior in flexibility.

Japanese Patent No. 471354 Japanese Patent Application Laid-Open No. 2009-186954 Japanese Patent Application Laid-Open No. 2010-248387

  The present invention has less damage to the optical substrate, and has good productivity, and can obtain an optical member such as a display unit having good curability and adhesion, and has high adhesiveness to the substrate. An optical member having a high adhesive strength (such as a touch panel) can be obtained even when an ultraviolet curable adhesive composition is applied to an optical substrate and then the applied layer is irradiated with ultraviolet light and then the optical substrate is bonded. It is an object of the present invention to provide a UV curable adhesive composition for a touch panel that can be used.

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, completed the present invention. That is, the present invention relates to the following (1) to (12).
(1) An ultraviolet curing adhesive for a touch panel, comprising a polyurethane compound (E) obtained by reacting a compound (A) shown below with a compound (B), a compound (C) and a compound (D). Composition.
Compound (A): hydrogenated polybutadiene polyol compound Compound (B): polyisocyanate compound Compound (C): (meth) acrylate compound having at least one or more hydroxyl group Compound (D): diol compound other than compound (A) ( 2) An ultraviolet-curable adhesive composition for a touch panel, comprising the polyurethane compound (E) according to (1), wherein the hydrogenated polybutadiene polyol compound (A) has an iodine value of 20 or less.
(3) An ultraviolet-curable adhesive composition for a touch panel, wherein the polyisocyanate compound (B) contains the polyurethane compound (E) according to (1) or (2), which is an aliphatic diisocyanate compound.
(4) The polyurethane compound (E) according to any one of (1) to (3), wherein the (meth) acrylate compound (C) having at least one or more hydroxyl groups is 2-hydroxyethyl (meth) acrylate. An ultraviolet-curable adhesive composition for a touch panel, comprising:
(5) UV curing for a touch panel, wherein the diol compound (D) other than the compound (A) contains the polyurethane compound (E) according to any one of (1) to (4), which is a polyether polyol. Mold adhesive composition.
(6) An ultraviolet-curable adhesive composition for a touch panel, comprising the polyurethane compound (E) according to any one of (1) to (5) and a polymerizable compound (F) other than (E). object.
(7) The ultraviolet-curable adhesive composition for a touch panel according to (6), wherein the polymerizable compound (F) is an alkyl (meth) acrylate or an alkylene (meth) acrylate.
(8) The ultraviolet-curable adhesive composition for a touch panel according to any one of (1) to (7), wherein the ultraviolet-curable composition contains the polyurethane compound (E) in an amount of 5% by mass or more. object.
(9) The ultraviolet-curable adhesive composition for a touch panel according to any one of (1) to (8), further including a softening component (G).
(10) The ultraviolet ray curable adhesive composition for a touch panel according to (9), wherein the softening component (G) contains one or both of a hydroxyl group-containing polymer and a terpene resin.
(11) A cured product obtained by irradiating the ultraviolet curable adhesive composition for a touch panel according to any one of (1) to (10) with an active energy ray.
(12) A touch panel comprising the ultraviolet-curable adhesive composition for a touch panel according to any one of (1) to (10).

  The cured film of the ultraviolet-curable adhesive composition containing the polyurethane compound of the present invention has excellent flexibility, high moisture resistance, high heat resistance, and high light resistance. This can be effectively prevented.

  The polyurethane compound (E) of the present invention is first reacted with a hydrogenated polybutadiene polyol (A) and a diol compound (D) other than the compound (A) with a polyisocyanate compound (B) (hereinafter referred to as a first reaction), And reacting a (meth) acrylate compound (C) having at least one hydroxyl group with respect to the remaining isocyanate group (hereinafter referred to as a second reaction). The obtained polyurethane compound (E) preferably has a weight average molecular weight of 5,000 to 30,000, more preferably 10,000 to 20,000, and particularly preferably 13,000 to 15,000. The R value is preferably from 1.1 to 2.0, more preferably from 1.1 to 1.5.

The hydrogenated polybutadiene polyol (A) used in the first reaction of the present invention can be used as long as it is a hydrogenated reduction product of a general polybutadiene polyol. Is preferable, and the iodine value is particularly preferably 20 or less.
The hydroxyl value is preferably 400 or less, more preferably 300 or less. The lower limit is not particularly limited, but may be, for example, 0.1 or more. Regarding the molecular weight of (A), any of those having a molecular weight distribution generally available can be used, but particularly when the flexibility and curability are balanced, those having a weight average molecular weight of 500 to 3000 are particularly preferred. . On the other hand, with regard to the molecular weight of (A), any of those having a molecular weight distribution generally available can be used, but particularly when the flexibility and curability are balanced, those having a number average molecular weight of 500 to 5,000 are preferable, Those with 500 to 3000 are particularly preferred.
Commercially available hydrogenated polybutadiene polyols (A) include, for example, GI-1000, GI-2000, GI-3000 manufactured by Nippon Soda Co., Ltd., KRASOL HLBP-H1000, HLBP-H2000, HLBP-H manufactured by CRAY VALLEY. 3000 and the like. In addition, the thing containing an alkali salt can be used suitably.

Specific examples of the diol compound (D) other than the compound (A) used in the first reaction of the present invention include polyethers such as polyethylene glycol, polybutylene glycol, polytetramethylene glycol, polypropylene glycol, and polyethylene glycol. Polyols, polyethylene glycol adipate, poly-1,4-butanediol adipate, polyester polyols such as polycaprolactone, ethylene glycol, propylene glycol, butanediol, pentanediol, glycols such as hexanediol and neopentyl glycol, cyclohexane dimethylol, Polyisoprene glycol, polybutadiene glycol, hydrogenated bisphenol A, hydrogenated bisphenol F, spiro skeleton-containing alcohol, tricyclodeca Alicyclic alcohols such as dimethylol and pentacyclopentadecane dimethylol and their alkylene oxide adducts, branched or linear long-chain alkyl diols such as diols of hydrogenated polyisoprene and hydrogenated polybutadiene, bisphenol A, bisphenol F, etc. Bisphenols, and alkylene oxide adducts of bisphenol, polyols such as trimethylolpropane, ditrimethylolpropane, pentaerythritol and dipentaerythritol, and alkylene oxide adducts of these polyols, and furthermore, these polyols and polybases such as adipic acid Examples thereof include polyester polyols obtained by the reaction of an acid. Although not particularly limited, use of polyether polyols is particularly preferable for improving flexibility and compatibility in the cured product of the ultraviolet-curable adhesive composition of the present invention.
As for the molecular weight of the diol compound (D) other than the compound (A), any of those having a generally available molecular weight distribution can be used, but especially when the flexibility and curability are balanced, the number average molecular weight is 50. -6000 are preferable, and 100-4000 are especially preferable.
Here, in the obtained polyurethane compound (E), a structure derived from a diol compound (D) (particularly preferably a polyether polyol such as polyethylene glycol) other than the compound (A) is dispersedly incorporated, and a polyethylene glycol skeleton and water The number average molecular weight of polyethylene glycol is more preferably 2,000 or less, particularly preferably 500 or less, from the viewpoint of increasing the compatibility with the monomer by uniformly incorporating the added polybutadiene skeleton.
Further, in the polyurethane compound (E), a diol compound (D) other than the compound (A) (particularly preferably a polyether polyol such as polyethylene glycol) is used in combination with the hydrogenated polybutadiene polyol (A) and a diol other than the compound (A). From the viewpoint of the total number of moles with the compound (D) (particularly preferably a polyether polyol such as polyethylene glycol), it is preferable that 5 to 10 mol% is incorporated.
The hydroxyl value is preferably 400 or less, more preferably 300 or less. The lower limit is not particularly limited, but may be, for example, 5 or more.

  As specific examples of polyethylene glycol which is an example of the polyether polyols which can be suitably used in the first reaction of the present invention, all commercially available polyethylene glycols can be used, and for example, NOF Corporation PEG # 200T, PEG # 200, PEG # 300, PEG # 400, PEG # 600, PEG # 1000, PEG # 1500, PEG # 1540, PEG # 200, PEG # 4000, PEG # 4000P, PEG # 6000, PEG # 6000P, PEG # 11000, PEG # 20000, etc., and urethane grades whose moisture is controlled can also be used. The water content is preferably 2% or less, particularly preferably 1% or less, in order to suppress the viscosity increase due to the increase in molecular weight.

Here, in the present invention, hydrogenated polybutadiene (A) and diol compound (D) other than compound (A) (particularly preferably polyether polyol such as polyethylene glycol) are used in the reaction. ) And the diol compound (D) (especially preferably a polyether polyol such as polyethylene glycol) other than the compound (A) are not particularly limited, but the molar ratio of the component (A) to the component (D) is 9.999. : 0.001 to 1: 9, more preferably 9.999: 0.001 to 3: 7, and particularly preferably 9.999: 0.001 to 4: 6.
Regarding the number average molecular weight of the hydrogenated polybutadiene polyol (A) used in the present invention, the number average molecular weight of the diol compound (D) other than the compound (A) used (particularly preferably a polyether polyol such as polyethylene glycol) is used. It is preferred to use a larger one in combination. The number average molecular weight of the diol compound (D) other than the compound (A) (particularly preferably a polyether polyol such as polyethylene glycol) + the number average molecular weight of 500 is determined as hydrogenated polybutadiene polyol ( More preferably, the hydrogenated polybutadiene polyol (A) has the number average molecular weight of the diol compound (D) other than the compound (A) (particularly preferably a polyether polyol such as polyethylene glycol) +1000. Especially to have Masui.

  The polyisocyanate compound (B) used in the first reaction of the present invention is a compound containing two or more isocyanate groups in one molecule, such as an aliphatic diisocyanate compound and an aromatic diisocyanate compound. And trimeric compounds thereof. The aliphatic diisocyanate compound referred to herein means a diisocyanate compound in which an isocyanate group is bonded to a chain carbon atom and a diisocyanate compound in which an isocyanate group is bonded to a carbon atom of a cyclic saturated hydrocarbon, and an aromatic diisocyanate compound. Means an isocyanate compound in which an isocyanate group is bonded to a carbon atom of an aromatic ring.

  Examples of the aliphatic diisocyanate compound include 1,6-hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,3-diisocyanate cyclohexane, and 1,4-diisocyanate Cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, m-tetramethylxylene diisocyanate, p-tetramethylxylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,2,4-trimethylcyclohexane Diisocyanate, 2,4,4-trimethylcyclohexane diisocyanate, 2,2,4-trimethylhexamethylene diisocy Sulfonate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate and the like.

  Examples of the aromatic diisocyanate compound include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, 1,6-phenylene diisocyanate, 1,4-phenylene diisocyanate, and 1,6-phenylene. And diisocyanate monomers such as diisocyanate.

  Among these, an aliphatic diisocyanate compound and a trimer of the aliphatic diisocyanate compound are preferable for improving the moisture resistance and heat resistance of the coating film. Examples of the trimer of the aliphatic diisocyanate compound include the above-mentioned aliphatic isocyanate-based isocyanurate-type polyisocyanate, and specific examples thereof include hexamethylene diisocyanate and isophorone diisocyanate. These may be used alone or in a mixture.

  In the present invention, the first reaction is charged in an equivalence relation (B / (A + D)> 1: [NCO] / [OH] molar ratio) such that an isocyanate group remains after the reaction. If the charge ratio is increased, a large amount of unreacted polyisocyanate compound (B) is present, which may affect the flexibility of the ultraviolet-curable adhesive composition. In addition, when the charge ratio is reduced, the molecular weight increases, which may affect the curability of the ultraviolet-curable adhesive composition. Specifically, preferably, the OH group of the alcohol compound (A + D) is 0.1 to 0.9 mol with respect to 1.0 mol of the NCO group of the polyisocyanate compound (B).

  In the present invention, the first reaction can be carried out without a solvent, but in a solvent having no alcoholic hydroxyl group or a polymerizable compound (F) described later for improving the workability because the viscosity of the product is high. It is preferred to do so. Specific examples of the solvent include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; aromatic hydrocarbons such as benzene, toluene, xylene, and tetramethylbenzene; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and dipropylene glycol. Glycol ethers such as dimethyl ether, dipropylene glycol diethyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether, ethyl acetate, butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate , Propylene glycol monoethyl ether acetate, Esters such as propylene glycol monomethyl ether acetate, dialkyl glutarate, dialkyl succinate and dialkyl adipate, cyclic esters such as γ-butyrolactone, petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, solvent naphtha, etc. In a single or mixed organic solvent.

  The reaction temperature is usually in the range of 30 to 150 ° C, preferably 50 to 100 ° C. The end point of the reaction is confirmed by the decrease in the amount of isocyanate. Further, a catalyst may be added for the purpose of shortening the reaction time. As this catalyst, either a basic catalyst or an acidic catalyst is used. Examples of the basic catalyst include amines such as pyridine, pyrrole, triethylamine, diethylamine, dibutylamine and ammonia, and phosphines such as tributylphosphine and triphenylphosphine. Examples of the acidic catalyst include copper naphthenate, cobalt naphthenate, zinc naphthenate, aluminum tributoxide, titanium tetraisopropoxide, zirconium tetrabutoxide, aluminum chloride, tin octylate, octyltin trilaurate, dibutyltin dilaurate, Lewis acid catalysts such as octyltin diacetate can be mentioned. The addition amount of these catalysts is usually 0.1 to 1 part by weight based on 100 parts by weight of the total weight of the diol compound (A + D) and the polyisocyanate compound (B).

  The polyurethane compound (E) of the present invention is obtained by reacting the (meth) acrylate compound (C) having at least one or more hydroxyl groups with respect to the remaining isocyanate groups after the first reaction (second reaction). be able to.

  The (meth) acrylate compound (C) having at least one hydroxyl group used in the second reaction of the present invention is a compound having at least one hydroxyl group and at least one (meth) acrylate in one molecule. Specifically, 2-hydroxyethyl (meth) acrylate, propylene glycol mono (meth) acrylate, butanediol mono (meth) acrylate, pentanediol mono (meth) acrylate, hexanediol mono (meth) acrylate, diethylene glycol mono ( (Meth) acrylate, dipropylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tripropylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, polyethylene Divalent such as glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, ethoxylated neopentyl glycol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate hydroxypivalate Mono (meth) acrylates of alcohols;

  Trimethylolpropane mono (meth) acrylate, ethoxylated trimethylolpropane mono (meth) acrylate, propoxylated trimethylolpropane mono (meth) acrylate, tris (2-hydroxyethyl) isocyanurate mono (meth) acrylate, glycerin mono (meth) A) acrylate, trimethylolpropanedi (meth) acrylate, ethoxylated trimethylolpropanedi (meth) acrylate, propoxylated trimethylolpropanedi (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, glycerin Monohydric and di (meth) acrylates of trihydric alcohols such as di (meth) acrylate, and some of the hydroxyl groups of these alcohols are substituted with alkyl groups or ε-caprolactone. Modified mono- and di (meth) acrylate;

  Pentaerythritol mono (meth) acrylate, dipentaerythritol mono (meth) acrylate, ditrimethylolpropane mono (meth) acrylate, pentaerythritol di (meth) acrylate, dipentaerythritol di (meth) acrylate, ditrimethylolpropane di (meth) Acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol hexa Polyfunctional (meth) acrylates such as (meth) acrylate and ditrimethylolpropane hexa (meth) acrylate ) And those having a hydroxyl group in acrylates, polyfunctional (meth) acrylate having a hydroxyl group partially modified with an alkyl group and ε- caprolactone hydroxyl groups of these alcohols, and the like.

  Among the (meth) acrylate compounds (C) having at least one or more hydroxyl groups, 2-hydroxyethyl (meth) acrylate is particularly preferred from the viewpoint of excellent curability and flexibility. From the viewpoint of easy workability, a polymerizable compound (F) described later in the present invention may be added during the reaction.

  In the second reaction of the present invention, the intermediates obtained after the first reaction are charged in an equivalence relation such that the isocyanate groups are eliminated. Specifically, preferably, the OH group of the (meth) acrylate compound (C) having at least one hydroxyl group per 1.0 mol of the NCO group of the intermediate obtained after the first reaction is 1.0 to 3.0. 0 mol, more preferably 1.0 to 2.0 mol.

  The second reaction of the present invention can also be carried out without a solvent, but is preferably carried out in the above-mentioned solvent and / or in the polymerizable compound (F) described below in order to improve the workability because the viscosity of the product is high. . The reaction temperature is usually in the range of 30 to 150 ° C, preferably 50 to 100 ° C. The end point of the reaction is confirmed by the decrease in the amount of isocyanate. The catalyst described above may be added for the purpose of shortening the reaction time.

  Usually, a polymerization inhibitor such as 4-methoxyphenol has already been added to the acrylate compound used as a raw material, but a polymerization inhibitor may be added again during the reaction. Examples of such polymerization inhibitors include hydroquinone, 4-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butyl-4-cresol, 3-hydroxythiophenol, p-benzoquinone, 2,5-dihydroxy-p-benzoquinone, phenothiazine and the like. The amount used is 0.01 to 1% by weight based on the reaction raw material mixture.

The ultraviolet-curable adhesive composition for a touch panel of the present invention can contain the polyurethane compound (E) of the present invention and a polymerizable compound (F) other than the component (E). The polymerizable compound (F) is not particularly limited, but is selected from the group consisting of urethane (meth) acrylate, (meth) acrylate having a polyisoprene skeleton, (meth) acrylate having a polybutadiene skeleton, and (meth) acrylate monomer. It is preferable to use any one of these. More preferably, the embodiment includes both (i) urethane (meth) acrylate and / or (meth) acrylate having a polyisoprene skeleton and (ii) (meth) acrylate monomer.
In this specification, “(meth) acrylate” means one or both of methacrylate and acrylate. The same applies to “(meth) acrylic acid” and the like.

  The urethane (meth) acrylate that can be used in combination with the ultraviolet-curable adhesive composition for a touch panel of the present invention is obtained by reacting a hydroxy compound having at least one (meth) acryloyloxy group with an isocyanate compound (further as an optional component, a polyol). It is a generic term for the (meth) acrylates obtained.

  Specific examples of the hydroxy compound having at least one (meth) acryloyloxy group include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, Hydroxyethyl (meth) acrylate, cyclohexane dimethanol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) A) a methacrylate compound having various hydroxyl groups such as acrylate, and a ring-opening reaction product of the (meth) acrylate compound having a hydroxyl group with ε-caprolactone. Can.

  Specific examples of the isocyanate compound include, for example, P-phenylene diisocyanate, m-phenylene diisocyanate, P-xylene diisocyanate, m-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4 ′ Aromatic diisocyanates such as diphenylmethane diisocyanate and naphthalene diisocyanate; aliphatic or alicyclic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate, and lysine diisocyanate. One or more burettes of isocyanate monomer or trimerization of the diisocyanate compound Polyisocyanate of the isocyanate and the like; the and the isocyanate compound include polyisocyanates obtained by urethane reaction of the polyol compound.

  The polyol that can be used as an optional component is not particularly limited as long as it is known. Specific examples include, for example, polyether polyols such as polyethylene glycol, polybutylene glycol, polytetramethylene glycol, polypropylene glycol, and polyethylene glycol, and polyester polyols such as polyethylene glycol adipate, poly-1,4-butanediol adipate, and polycaprolactone. , Ethylene glycol, propylene glycol, butanediol, pentanediol, glycols such as hexanediol and neopentyl glycol, cyclohexane dimethylol, polyisoprene glycol, polybutadiene glycol, hydrogenated bisphenol A, hydrogenated bisphenol F, spiro skeleton-containing alcohol, Alicyclic alkyls such as tricyclodecane dimethylol and pentacyclopentadecane dimethylol Alkylene oxide adducts thereof, hydrogenated polyisoprene, branched or linear long-chain alkyl diols such as diols of hydrogenated polybutadiene, bisphenols such as bisphenol A and bisphenol F, and alkylene oxide adducts of bisphenol, Polyols such as trimethylolpropane, ditrimethylolpropane, pentaerythritol and dipentaerythritol; alkylene oxide adducts of these polyols; and polyester polyols obtained by the reaction of these polyols with polybasic acids such as adipic acid. be able to. Although not particularly limited, use of polyether polyols is particularly preferable for improving flexibility and compatibility in the cured product of the ultraviolet-curable adhesive composition of the present invention.

  The weight average molecular weight of the urethane (meth) acrylate is preferably about 7000 to 25,000, more preferably 10,000 to 20,000. If the weight average molecular weight is smaller than 7,000, shrinkage increases, and if the weight average molecular weight is larger than 25,000, curability becomes poor.

  In the ultraviolet-curable adhesive composition of the present invention, one or more urethane (meth) acrylates can be used by mixing at an arbitrary ratio. The weight ratio of the urethane (meth) acrylate in the ultraviolet ray curable composition for a touch panel of the present invention is usually 20 to 80% by weight, preferably 30 to 70% by weight.

The (meth) acrylate having a polyisoprene skeleton has a (meth) acryloyl group at a terminal or a side chain of a polyisoprene molecule. The (meth) acrylate having a polyisoprene skeleton can be obtained as "UC-203" (manufactured by Kuraray Co., Ltd.). The (meth) acrylate having a polyisoprene skeleton has a number average molecular weight in terms of polystyrene of preferably from 1,000 to 50,000, more preferably about 25,000 to 45,000.
The weight ratio of the (meth) acrylate having a polyisoprene skeleton in the photocurable transparent adhesive composition of the present invention is usually 20 to 80% by weight, preferably 30 to 70% by weight.

The (meth) acrylate having a polybutadiene skeleton has a (meth) acryloyl group at a terminal or a side chain of a polybutadiene molecule. The (meth) acrylates having a polybutadiene skeleton are "TEAI-1000 (manufactured by Nippon Soda Co., Ltd.)", "TE-2000 (manufactured by Nippon Soda Co., Ltd.)", "EMA-3000 (manufactured by Nippon Soda Co., Ltd.)", and "SPBDA-S30 (Osaka Organic Chemicals). Industrial Co., Ltd.). The (meth) acrylate having a polybutadiene skeleton preferably has a number average molecular weight in terms of polystyrene of 1,000 to 30,000, more preferably about 1,000 to 10,000.
The weight ratio of the (meth) acrylate having a polybutadiene skeleton in the photocurable transparent adhesive composition of the present invention is usually 10 to 80% by weight, preferably 20 to 70% by weight.

As the (meth) acrylate monomer, a (meth) acrylate having one (meth) acryloyl group in a molecule can be preferably used.
Here, the (meth) acrylate monomer refers to (meth) acrylate excluding the urethane (meth) acrylate, the following epoxy (meth) acrylate, and the (meth) acrylate having a polyisoprene skeleton.

Specific examples of the (meth) acrylate having one (meth) acryloyl base in a molecule include isooctyl (meth) acrylate, isoamyl (meth) acrylate, lauryl (meth) acrylate, isodecyl (meth) acrylate, and stearyl (meth) acrylate. C5-C20 alkyl (meth) acrylates such as meth) acrylate, cetyl (meth) acrylate, isomiristyl (meth) acrylate, and tridecyl (meth) acrylate (preferably 10 carbon atoms from the viewpoint of volatility and solubility) To 20 alkyl (meth) acrylates, more preferably branched-chain alkyl (meth) acrylates having 10 to 20 carbon atoms), benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acryloylmorpholine, phenylglycine (Meth) acrylate, tricyclodecane (meth) acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 1-adamantyl acrylate, Having a cyclic skeleton such as -methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate, 1-adamantyl methacrylate, polypropylene oxide-modified nonylphenyl (meth) acrylate, dicyclopentadieneoxyethyl (meth) acrylate, etc. A) C1-C5 alkyl (meth) acryl having a hydroxyl group such as acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; Polyalkylene glycol (meth) acrylate such as ethoxydiethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polypropylene oxide-modified nonylphenyl (meth) acrylate, ethylene oxide-modified phenoxylated phosphoric acid (meth) acrylate, and ethylene oxide-modified butoxy Phosphorylated (meth) acrylate and ethylene oxide-modified octyloxylated phosphoric acid (meth) acrylate. Among them, alkyl (meth) acrylate having 10 to 20 carbon atoms, 2-ethylhexyl carbitol acrylate, acryloyl morpholine, 4-hydroxybutyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isostearyl (meth) acrylate, dicyclo Pentenyloxyethyl (meth) acrylate and polypropylene oxide-modified nonylphenyl (meth) acrylate are preferred. In particular, from the viewpoint of flexibility of the resin, alkyl (meth) acrylate having 10 to 20 carbon atoms, dicyclopentenyloxyethyl (meth) Acrylate, polypropylene oxide-modified nonylphenyl (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate are preferred.
On the other hand, from the viewpoint of improving the adhesion to glass, an alkyl (meth) acrylate having 1 to 5 carbon atoms having a hydroxyl group and acryloylmorpholine are preferable, and acryloylmorpholine is particularly preferable.
Here, the (meth) acrylate monomer refers to (meth) acrylate excluding urethane (meth) acrylate, epoxy (meth) acrylate, and (meth) acrylate having a polyisoprene skeleton.

The composition of the present invention may contain a (meth) acrylate other than a (meth) acrylate having one (meth) acryloyl group as long as the properties of the present invention are not impaired. For example, tricyclodecane dimethylol di (meth) acrylate, dioxane glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, alkylene oxide-modified bisphenol A type di (meth) acrylate C2-C10 alkanes such as caprolactone-modified neopentyl glycol hydroxypivalate di (meth) acrylate and ethylene oxide-modified di (meth) acrylate, trimethylolpropanetri (meth) acrylate, trimethyloloctanetri (meth) acrylate Tri (meth) acrylate, trimethylolpropanepolyethoxytri (meth) acrylate, trimethylolpropanepolypropoxytri ( T) acrylate, trimethylolpropanepolyethoxypolypropoxytri (meth) acrylate, etc., trimethylol C2 to C10 alkanepolyalkoxytri (meth) acrylate, tris [(meth) acryloyloxyethyl] isocyanurate, pentaerythritol tri ( Alkylene oxide-modified trimethylolpropane tri (meth) acrylate such as meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, and propylene oxide-modified trimethylolpropane tri (meth) acrylate pentaerythritol polyethoxytetra (meth) acrylate; Pentaerythritol polypropoxytetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrime Trimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.
In the present invention, when used in combination, it is preferable to use a mono- or bifunctional (meth) acrylate in order to suppress curing shrinkage.

In the ultraviolet-curable adhesive composition of the present invention, one or more of these (meth) acrylate monomer components can be used by mixing at an arbitrary ratio. The weight ratio of the (meth) acrylate monomer in the photocurable transparent adhesive composition of the present invention is usually 5 to 70% by weight, preferably 10 to 50% by weight. If it is less than 5% by weight, the curability will be poor, and if it is more than 70% by weight, the shrinkage will be large.
In the embodiment containing both (i) urethane (meth) acrylate or (meth) acrylate having a polyisoprene skeleton and (ii) (meth) acrylate monomer in the ultraviolet-curable adhesive composition, , (I) and (ii) are usually from 25 to 90% by weight, from 40 to 90% by weight, more preferably from 40 to 80% by weight, based on the total amount of the resin composition.

  Epoxy (meth) acrylate can be used in the ultraviolet-curable adhesive composition for a touch panel of the present invention as long as the properties of the present invention are not impaired. Epoxy (meth) acrylate has a function of improving curability and improving the hardness and curing speed of a cured product. Epoxy (meth) acrylate is a general term for (meth) acrylate obtained by reacting an epoxy resin containing an epoxy group having one or more functionalities with (meth) acrylic acid. (Meth) acrylic acid is reacted at a ratio of 0.9 to 1.5 mol, more preferably 0.95 to 1.1 mol, per 1 equivalent of the epoxy group of the glycidyl ether type epoxy compound. The reaction temperature is preferably from 80 to 120C, and the reaction time is from about 10 to 35 hours. In order to accelerate the reaction, it is preferable to use a catalyst such as triphenylphosphine, TAP, triethanolamine, tetraethylammonium chloride and the like. In addition, for preventing polymerization during the reaction, for example, paramethoxyphenol, methylhydroquinone and the like can be used as a polymerization inhibitor. Specific examples of the epoxy resin used as a raw material of the epoxy (meth) acrylate include phenyl diglycidyl ethers such as hydroquinone diglycidyl ether, catechol diglycidyl ether, and resorcinol diglycidyl ether; bisphenol-A type epoxy resin and bisphenol-F type epoxy Resin, bisphenol-S type epoxy resin, bisphenol type epoxy compound such as 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane epoxy compound; hydrogenated bisphenol- A type epoxy resin, hydrogenated bisphenol-F type epoxy resin, hydrogenated bisphenol-S type epoxy resin, hydrogenated 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexa Epoxy of Fluoropropane Hydrogenated bisphenol type epoxy compounds such as compounds; halogenated bisphenol type epoxy compounds such as brominated bisphenol-A type epoxy resin and brominated bisphenol-F type epoxy resin; alicyclic diglycidyl such as cyclohexane dimethanol diglycidyl ether compound Ether compounds; aliphatic diglycidyl ether compounds such as 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether and diethylene glycol diglycidyl ether; polysulfide-type diglycidyl ether compounds such as polysulfide diglycidyl ether; Novolak epoxy resin, cresol novolak epoxy resin, trishydroxyphenylmethane epoxy resin, dicyclopentadiene phenol Epoxy resins, biphenol type epoxy resin, bisphenol -A novolac epoxy resins, naphthalene skeleton-containing epoxy resin, a heterocyclic epoxy resin or the like.

The epoxy (meth) acrylate that can be suitably used in the present invention is a bisphenol A type epoxy (meth) acrylate obtained from a bisphenol A type epoxy compound. The weight average molecular weight of the epoxy (meth) acrylate is preferably from 500 to 10,000.
The weight ratio of the epoxy (meth) acrylate in the ultraviolet-curable adhesive composition of the present invention is usually 1 to 80% by weight, preferably 5 to 30% by weight.

The content ratio of the (meth) acrylate in the ultraviolet-curable resin composition of the present invention is 25 to 90% by weight, preferably 40 to 90% by weight, and more preferably the total amount of the ultraviolet-curable adhesive composition. Is 40 to 80% by weight.
In the ultraviolet-curable adhesive composition of the present invention, the (meth) acrylate is at least selected from the group consisting of the urethane (meth) acrylate, the (meth) acrylate having the polyisoprene skeleton, and the (meth) acrylate monomer. Preferably, the content of the urethane (meth) acrylate is 20 to 80% by weight, preferably 30 to 70% by weight, and the content of the (meth) acrylate having a polyisoprene skeleton is 20. It is more preferably from 80 to 80% by weight, preferably from 30 to 70% by weight, and more preferably from 5 to 70% by weight, preferably from 10 to 50% by weight, of the (meth) acrylate monomer.
In the ultraviolet-curable adhesive composition of the present invention, the urethane (meth) acrylate or the (meth) acrylate having a polyisoprene skeleton is contained as the (meth) acrylate, and the content thereof is 20 to 80% by weight, preferably It is more preferable that the content is 30 to 70% by weight and that the composition contains a (meth) acrylate monomer and the content ratio is 5 to 70% by weight, preferably 10 to 50% by weight.

  Examples of the maleimide group-containing compound that can be used in combination with the ultraviolet-curable adhesive composition for a touch panel of the present invention include, for example, Nn-butylmaleimide, N-hexylmaleimide, 2-maleimidoethyl-ethylcarbonate, and 2-maleimide. Monofunctional aliphatic maleimides such as ethyl-propyl carbonate, N-ethyl- (2-maleimidoethyl) carbamate; alicyclic monofunctional maleimides such as N-cyclohexylmaleimide; N, N-hexamethylenebismaleimide, polypropylene glycol Aliphatic bismaleimides such as -bis (3-maleimidopropyl) ether and bis (2-maleimidoethyl) carbonate; alicyclic bis such as 1,4-dimaleimidocyclohexane and isophoronebisurethanebis (N-ethylmaleimide) Maleimide; Murray A maleimide compound obtained by esterifying acetic acid and polytetramethylene glycol, a carboxymaleimide derivative such as a maleimide compound obtained by esterification of maleimidocaproic acid with a tetraethylene oxide adduct of pentaerythritol, and various (poly) ols. Examples thereof include (poly) ester (poly) maleimide compounds obtained by esterification, but are not limited thereto. The content ratio is from 25 to 90% by weight, preferably from 40 to 90% by weight, and more preferably from 40 to 80% by weight, based on the total amount of the ultraviolet-curable adhesive composition.

  Examples of the (meth) acrylamide compound that can be used in combination with the ultraviolet-curable adhesive composition for a touch panel of the present invention include monofunctional (meth) acrylamides such as acryloylmorpholine and N-isopropyl (meth) acrylamide; ) Polyfunctional (meth) acrylamides such as acrylamide. The content ratio is from 25 to 90% by weight, preferably from 40 to 90% by weight, and more preferably from 40 to 80% by weight, based on the total amount of the ultraviolet-curable adhesive composition.

  The photopolymerization initiator contained in the composition of the present invention is not particularly limited, but it is preferable to use an acylphosphine oxide compound. For example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2 6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide. When irradiating the UV-curable resin after application with ultraviolet rays to obtain a cured layer having a cured portion present on the optical substrate side and an uncured portion present on the opposite side to the optical substrate side, an uncured portion is obtained. 2,4,6-trimethylbenzoyldiphenylphosphine oxide is particularly preferred from the viewpoints of ease of formation and transparency of the cured resin layer.

  Other photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone (Irgacure 184; manufactured by BASF) and 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer (Esacure ONE; 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (Irgacure 2959; BASF), 2-hydroxy-1- {4 -[4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one (Irgacure 127; manufactured by BASF), 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651; manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl- Lopan-1-one (Darocure 1173; manufactured by BASF), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Irgacure 907; manufactured by BASF), oxy-phenyl-acetone Mixture of tic acid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] -ethyl ester and oxy-phenyl-acetyl acid 2- [2-hydroxy-ethoxy] -ethyl ester (Irgacure 754; BASF) , 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, isopropylthioxanthone and the like. Can be.

  In the ultraviolet-curable adhesive composition for a touch panel of the present invention, one or more of these photopolymerization initiators can be used by mixing at an arbitrary ratio. The weight ratio of the photopolymerization initiator in the photocurable resin composition of the present invention is usually 0.2 to 5% by weight, preferably 0.3 to 3% by weight. When the content is more than 5% by weight, when obtaining a cured product layer having a cured portion and an uncured portion present on the side opposite to the optical substrate side, the uncured portion cannot be formed or the transparency of the cured resin layer is reduced. It may be worse.

  Further, it is used in combination with a tertiary amine such as triethanolamine and methyldiethanolamine, and an accelerator such as benzoic acid derivative such as ethyl N, N-dimethylaminobenzoate and isoamyl N, N-dimethylaminobenzoate. can do. The amount of these accelerators to be added is 100% by weight or less based on the photopolymerization initiator, if necessary.

  The ultraviolet-curable adhesive composition for a touch panel of the present invention comprises, in addition to the (meth) acrylate and the photopolymerization initiator, other components such as a photopolymerization initiation aid described below and a general formula (1) described below. Having the following structure, a softening component (G) described later, an additive described later, and the like. The content ratio of the other components with respect to the total amount of the ultraviolet-curable adhesive composition of the present invention is a balance obtained by subtracting the total amount of the (meth) acrylate and the photopolymerization initiator from the total amount. Specifically, the total amount of the other components is 0 to 74% by weight, preferably about 5 to 70% by weight, based on the total amount of the ultraviolet-curable adhesive composition of the present invention.

  Further, amines and the like which can be a photopolymerization initiation auxiliary agent can be used in combination with the above photopolymerization initiator. Examples of amines that can be used include 2-dimethylaminoethyl benzoate, dimethylaminoacetophenone, ethyl p-dimethylaminobenzoate, and isoamyl p-dimethylaminobenzoate. When a photopolymerization initiation aid such as an amine is used, the content in the adhesive resin composition of the present invention is usually 0.005 to 5% by weight, preferably 0.01 to 3% by weight.

  The ultraviolet-curable adhesive composition for a touch panel of the present invention can contain a compound having a structure represented by the general formula (1), if necessary.

(In the formula, n represents an integer of 0 to 40, m represents an integer of 10 to 50. R ¹ and R ² may be the same or different. R ¹ and R ^{2 each} have 1 to 1 carbon atoms. An alkyl group having 18 carbon atoms, an alkenyl group having 1 to 18 carbon atoms, an alkynyl group having 1 to 18 carbon atoms, and an aryl group having 5 to 18 carbon atoms.)

The compound having the structure represented by the general formula (1) can be obtained, for example, as Unisafe PKA-5017 (product name, polyethylene glycol-polypropylene glycol allyl butyl ether) manufactured by NOF Corporation.
The weight ratio of the compound having the structure represented by the general formula (1) in the ultraviolet-curable adhesive composition is usually 10 to 80% by weight, preferably 10 to 70% by weight.

In the ultraviolet-curable adhesive composition for a touch panel of the present invention, a softening component (G) can be used as necessary. Specific examples of the softening component that can be used include polymers or oligomers other than the (meth) acrylate or the compound having the structure represented by the general formula (1), phthalates, phosphates, glycol esters, and citrates. Examples include acid esters, aliphatic dibasic acid esters, fatty acid esters, epoxy plasticizers, castor oils, terpene hydrogenated resins, and the like. Examples of the above oligomers and polymers include oligomers or polymers having a polyisoprene skeleton, polybutadiene skeleton, polybutene skeleton or xylene skeleton, and esters thereof, and in some cases, polymers or oligomers having a polybutadiene skeleton and esters thereof. It is preferred to use a compound. Specific examples of the polymer or oligomer having a polybutadiene skeleton and its esterified product include a butadiene homopolymer, an epoxy-modified polybutadiene, a butadiene-styrene random copolymer, a maleic acid-modified polybutadiene, and a terminal hydroxyl group-modified liquid polybutadiene. Further, these softening components can be used in combination of two or more of the above components.
The weight ratio of such a softening component in the ultraviolet-curable adhesive composition is usually 10 to 80% by weight, preferably 10 to 70% by weight.

  The ultraviolet-curable adhesive composition for a touch panel of the present invention may optionally contain an antioxidant, an organic solvent, a silane coupling agent, a polymerization inhibitor, a leveling agent, an antistatic agent, a surface lubricant, and a fluorescent whitening agent. Further, additives such as a light stabilizer (for example, a hindered amine compound) and a filler may be added.

  Specific examples of the antioxidant include, for example, BHT, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine Pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-t-butyl- 4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3-t -Butyl-5-methyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N N-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t- Butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, octylated diphenylamine, 2,4-bis [(octylthio) methyl-O-cresol, Isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], dibutylhydroxytoluene and the like.

  Specific examples of the organic solvent include, for example, alcohols such as methanol, ethanol, and isopropyl alcohol, dimethyl sulfone, dimethyl sulfoxide, tetrahydrofuran, dioxane, toluene, and xylene.

  Specific examples of the silane coupling agent include, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy Cyclohexyl) ethyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, γ-mercapropropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3 -Aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane , 3 Silane coupling agents such as chloropropylmethyldimethoxysilane and 3-chloropropyltrimethoxysilane; isopropyl (N-ethylaminoethylamino) titanate, isopropyl triisostearoyl titanate, titanium di (dioctyl pyrophosphate) oxyacetate, tetra Titanium-based coupling agents such as isopropyldi (dioctylphosphite) titanate and neoalkoxytri (p-N- (β-aminoethyl) aminophenyl) titanate; Zr-acetylacetonate, Zr-methacrylate, Zr-propionate, neo Alkoxy zirconate, neoalkoxytris neodecanoyl zirconate, neoalkoxytris (dodecanoyl) benzenesulfonyl zirconate, neoalkoxytris ( Chi range aminoethyl) zirconate, neoalkoxy tris (m-aminophenyl) zirconate, ammonium zirconium carbonate, Al- acetylacetonate, Al- methacrylate, zirconium or the like Al- propionate, or aluminum coupling agent, and the like.

  Specific examples of the polymerization inhibitor include paramethoxyphenol, methylhydroquinone, and the like.

  Specific examples of the light stabilizer include, for example, 1,2,2,6,6-pentamethyl-4-piperidyl alcohol, 2,2,6,6-tetramethyl-4-piperidyl alcohol, 1,2,2 6,6-pentamethyl-4-piperidyl (meth) acrylate (LA-82, manufactured by Adeka Corp.), tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3, 4-butanetetracarboxylate, tetrakis (2,2,6,6-totramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5.5] Undeca Mixed ester with bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1-undecaneoxy-2,2,6,6-tetramethylpiperidin-4-yl) ) Carbonate, 2,2,6,6, -tetramethyl-4-piperidyl methacrylate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6) -Pentamethyl-4-piperidyl) sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpi Lysine, 1,2,2,6,6-pentamethyl-4-piperidinyl-methacrylate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) [[3,5-bis (1,1 -Dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, bis (2,2,6,6-tetramethyl-1 (octyloxy) -4-piperidinyl) decane diester, 1,1-dimethylethyl The reaction product of hydroperoxide and octane, N, N ′, N ″, N ″ ″-tetrakis- (4,6-bis- (butyl- (N-methyl-2,2,6,6-tetramethylpiperidine- 4-yl) amino) -triazin-2-yl) -4,7-diazadecane-1,10-diamine, dibutylamine-1,3,5-triazine.N, N'-bis (2,2,6, 6-te Polycondensate of tramethyl-4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [[6- (1,1,3, 3- (tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6 , 6-Tetramethyl-4-piperidyl) imino]], a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 2,2,4,4-tetra Methyl-20- (β-lauryloxycarbonyl) ethyl-7-oxa-3,20-diazaspiro [5.1.11.2] heneikosan-21-one, β-alanine, N,-(2,2,6 , 6-tetra Methyl-4-piperidinyl) -dodecyl ester / tetradecyl ester, N-acetyl-3-dodecyl-1- (2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione, 2, 2,4,4-tetramethyl-7-oxa-3,20-diazaspiro [5,1,11,2] heneikosan-21-one, 2,2,4,4-tetramethyl-21-oxa-3, 20-diazadicyclo- [5,1,11,2] -heneicosan-20-propanoic acid dodecyl ester / tetradecyl ester, propane dioic acid, [(4-methoxyphenyl) -methylene] -bis (1,2,2 , 6,6-pentamethyl-4-piperidinyl) ester, higher fatty acid esters of 2,2,6,6-tetramethyl-4-piperidinol, 1,3- Hindered amine compounds such as benzene dicarboxamide, N, N'-bis (2,2,6,6-tetramethyl-4-piperidinyl), benzophenone compounds such as octabenzone, 2- (2H-benzotriazole-2) -Yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- [2-hydroxy-3- (3,4, 5,6-tetrahydrophthalimido-methyl) -5-methylphenyl] benzotriazole, 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy- 3,5-di-tert-pentylphenyl) benzotriazole, methyl 3- (3- (2H-benzotriazole-2-i) ) -5-tert-butyl-4-hydroxyphenyl) propionate and the reaction product of polyethylene glycol, benzotriazole compounds such as 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol, Benzoate compounds such as 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, 2- (4,6-diphenyl-1,3,5-triazin-2-yl ) -5-[(hexyl) oxy] phenol and other triazine compounds, etc., with hindered amine compounds being particularly preferred.

  Specific examples of the filler include, for example, crystalline silica, fused silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, silicon nitride, boron nitride, zirconia, fosterite, steatite, spinel, titania, talc, and the like. Examples thereof include powders and spherical beads of these.

  When various additives are present in the composition, the weight ratio of the various additives in the photocurable transparent adhesive composition is 0.01 to 3% by weight, preferably 0.01 to 1% by weight, more preferably Is 0.02 to 0.5% by weight.

  The ultraviolet-curable adhesive composition for a touch panel of the present invention can be obtained by mixing and dissolving each of the above-described components at room temperature to 80 ° C., and if necessary, impurities may be removed by an operation such as filtration. It is preferable to appropriately adjust the compounding ratio of the components of the adhesive resin composition of the present invention so that the viscosity at 25 ° C. is in the range of 300 to 15000 mPa · s in consideration of applicability.

The ultraviolet-curable adhesive composition for a touch panel of the present invention is used for manufacturing a touch panel by bonding at least two optical substrates, at least one of which is an optical substrate having a light shielding portion.
The curing shrinkage of the cured product of the ultraviolet-curable adhesive composition for a touch panel of the present invention is preferably 3.0% or less, particularly preferably 2.0% or less. Thereby, when the UV-curable adhesive composition is cured, the internal stress accumulated in the cured resin can be reduced, and the substrate and the layer composed of the cured product of the UV-curable adhesive composition can be reduced. It is possible to effectively prevent the interface from being distorted.
Further, when the substrate such as glass is thin, if the curing shrinkage is large, the warpage during curing becomes large, so that the display performance is greatly affected.From this viewpoint, the curing shrinkage is small. Is more preferred.

The transmittance of the cured product of the ultraviolet-curable adhesive composition for a touch panel of the present invention at 400 nm to 800 nm is preferably 90% or more. When the transmittance is less than 90%, light is hardly transmitted, and when used for a display device, visibility is reduced.
Further, if the transmittance of the cured product at 400 to 450 nm is high, the visibility can be further expected to be improved. Therefore, the transmittance at 400 to 450 nm is preferably 90% or more.

The ultraviolet-curable adhesive composition for a touch panel of the present invention can be suitably used as an adhesive for manufacturing an optical member by laminating a plurality of optical substrates.
Examples of the optical substrate used in the method for producing an optical member of the present invention include a transparent plate, a sheet, a touch panel, and a display unit.
In the present invention, the “optical base” means both an optical base having no light-shielding portion on the surface and an optical base having a light-shielding portion on the surface. In the production of the optical member of the present invention, preferably, at least one of the plurality of optical base materials used is an optical base material having a light shielding portion.
The position of the light-shielding portion in the optical substrate having the light-shielding portion is not particularly limited. In a preferred embodiment, a band-shaped light-shielding portion having a width of about 0.05 to 20 mm, preferably about 0.05 to 10 mm, and more preferably about 0.1 to 6 mm is formed around the optical substrate. Case. The light-shielding portion on the optical substrate can be formed by attaching a tape, applying a paint, or printing.

  Various materials can be used as the material of the optical substrate used in the present invention. Specific examples include PET, PC, PMMA, a composite of PC and PMMA, glass, COC, COP, and resins such as plastic (such as acrylic resin). The optical substrate used in the present invention, for example, as a transparent plate or sheet, a sheet or a transparent plate in which a plurality of films or sheets such as a polarizing plate are laminated, a non-laminated sheet or a transparent plate, and a transparent material formed from an inorganic glass Plates (inorganic glass plates and processed products thereof, for example, lenses, prisms, ITO glass) and the like can be used. In addition, the optical substrate used in the present invention may be a laminate (hereinafter, referred to as “functional laminate”) including a plurality of functional plates or sheets, such as a touch panel (touch panel input sensor) or the following display unit, in addition to the above-described polarizing plate. Body ").

Examples of the sheet that can be used as the optical substrate used in the present invention include an icon sheet, a decorative sheet, and a protective sheet. Examples of the plate (transparent plate) that can be used in the method for producing an optical member of the present invention include a decorative plate and a protective plate. As the material of these sheets or plates, those listed as the material of the transparent plate can be applied.
Examples of the material of the surface of the touch panel that can be used as the optical substrate used in the present invention include glass, PET, PC, PMMA, a composite of PC and PMMA, COC, and COP.
The thickness of a plate-shaped or sheet-shaped optical substrate such as a transparent plate or a sheet is not particularly limited, and is usually about 5 μm to about 5 cm, preferably about 10 μm to about 10 mm, and more preferably about 50 μm to 3 mm. Thickness.

As a preferred touch panel used in the present invention, a plate-shaped or sheet-shaped transparent optical base material having a light-shielding portion, and the above-mentioned functional laminate are attached with a cured product of the ultraviolet-curable adhesive composition for a touch panel of the present invention. The combined optical member can be mentioned.
In addition, by using a display unit such as a liquid crystal display device as one of the optical base materials and using an optical functional material as the other optical base material, a display unit with an optical functional material (hereinafter also referred to as a display panel). ) Can be manufactured. Examples of the display unit include a display device such as an LCD, an EL display, an EL illumination, an electronic paper, a plasma display, or the like in which a polarizing plate is attached to glass. Examples of the optical functional material include an acrylic plate, a PC plate, a transparent plastic plate such as a PET plate and a PEN plate, a tempered glass, and a touch panel input sensor.

When used as an adhesive for bonding an optical base material, when the refractive index of the cured product is 1.45 to 1.55 for improving visibility, it is preferable because the visibility of a display image is further improved.
When the refractive index falls within the range, the difference in the refractive index from the substrate used as the optical substrate can be reduced, and light loss can be reduced by suppressing irregular reflection of light.

  The optical member including the display unit knit obtained by the manufacturing method of the present invention and the optical base material having the light-shielding portion can be incorporated in electronic devices such as a television, a small game machine, a mobile phone, and a personal computer.

  The ultraviolet curable adhesive composition of the present invention has excellent flexibility, high moisture resistance, high heat resistance, and high light resistance, and fills the air gap of a display device such as a liquid crystal display device, an organic EL display device, and a touch panel type image display device. Useful for applications such as agents.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples.

Synthesis Example 1
In a reactor equipped with a reflux condenser, stirrer, thermometer, and temperature controller, GI-2000 manufactured by Nippon Soda Co., Ltd. (iodine value: 12.2, hydroxyl value: 46.8 mg · KOH) was used as a hydrogenated polybutadiene polyol compound. / G), 7.50 g (0.0024 mol) of Exenol 3020 (polypropylene glycol, hydroxyl value: 35.9 mg · KOH / g) manufactured by Asahi Glass Co., Ltd. as a diol compound, polymerizable 171.49 g of S-1800A (isostearyl acrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. as a compound and 0.41 g of 4-methoxyphenol as a polymerization inhibitor were added, and the mixture was stirred until it became uniform. did. Subsequently, 80.03 g (0.36 mol) of isophorone diisocyanate was added as a polyisocyanate compound and reacted at 80 ° C. until the target NCO content was reached. Next, 28.70 g (0.247 mol) of 2-hydroxyethyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd. as a (meth) acrylate compound having at least one or more hydroxyl groups, and tin octylate as a urethanation reaction catalyst at 0. .20 g was added and reacted at 80 ° C., and when the NCO content became 0.1% or less, the reaction was taken as the end point to obtain a polyurethane compound (E-1).

Synthesis Example 2
In a reactor equipped with a reflux condenser, stirrer, thermometer, and temperature controller, GI-2000 manufactured by Nippon Soda Co., Ltd. (iodine value: 12.2, hydroxyl value: 46.8 mg · KOH) was used as a hydrogenated polybutadiene polyol compound. / G), 5.19 g (0.0023 mol) of Exenol 3020 (polypropylene glycol, hydroxyl value: 35.9 mg · KOH / g) manufactured by Asahi Glass Co., Ltd. as a diol compound, polymerizable 208.51 g of S-1800A (isostearyl acrylate) manufactured by Shin-Nakamura Chemical Co., Ltd. as a compound and 0.37 g of 4-methoxyphenol as a polymerization inhibitor were added, and the mixture was stirred until it became uniform. did. Subsequently, 61.35 g (0.28 mol) of isophorone diisocyanate was added as a polyisocyanate compound and reacted at 80 ° C. until the target NCO content was reached. Next, 11.00 g (0.095 mol) of 2-hydroxyethyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd. as a (meth) acrylate compound having at least one hydroxyl group, and tin octylate as a urethanization reaction catalyst at 0 .20 g was added and reacted at 80 ° C., and when the NCO content became 0.1% or less, the reaction was terminated, thereby obtaining a polyurethane compound (E-2).

Synthesis Example 3
In a reactor equipped with a reflux condenser, a stirrer, a thermometer, and a temperature controller, as a hydrogenated polybutadiene polyol compound, KRASOL HLBH-P 2000 manufactured by CRAY VALLEY (iodine value: 13.5, hydroxyl value: 0.89 meq / g) 51.69 g (0.23 mol), 7.19 g (0.0023 mol) of Exenol 3020 (polypropylene glycol, hydroxyl value: 35.9 mg · KOH / g) manufactured by Asahi Glass Co., Ltd. as a diol compound, and a new polymerizable compound. 197.08 g of S-1800A (isostearyl acrylate) manufactured by Nakamura Chemical Co., Ltd. and 0.36 g of 4-methoxyphenol as a polymerization inhibitor were added, and the mixture was stirred until uniform, and the internal temperature was set to 50 ° C. Subsequently, 61.35 g (0.28 mol) of isophorone diisocyanate was added as a polyisocyanate compound and reacted at 80 ° C. until the target NCO content was reached. Next, 11.00 g (0.095 mol) of 2-hydroxyethyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd. as a (meth) acrylate compound having at least one hydroxyl group, and tin octylate as a urethanization reaction catalyst at 0 .20 g was added and reacted at 80 ° C., and when the NCO content became 0.1% or less, the reaction was terminated, thereby obtaining a polyurethane compound (E-3).

Example 1
20 parts by mass of the polyurethane compound (E-1) of Synthesis Example 1, 22 parts by mass of S-1800A (isostearyl acrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., 10 parts by mass of Blenmer LA (lauryl acrylate) manufactured by NOF Corporation, 18 parts by mass of Clearon M-105 (aromatic modified hydrogenated terpene resin) manufactured by Yashara Chemical Co., Ltd .; 10 parts by mass of LV-100 (polybutene) manufactured by JX Nippon Oil & Energy Corporation; GI-2000 manufactured by Nippon Soda Co., Ltd. 20 parts by mass of (1,2-hydrogenated polybutadiene glycol), 0.5 parts by mass of Speed Cure TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide) manufactured by LAMBSON, and IRGACURE 184 (1-hydroxycyclohexylphenyl) manufactured by BASF 0.5 parts by mass of ketone), PBD (2- (4-biphenyl) manufactured by Wako Pure Chemical Industries, Ltd. ) -5- (4-t-butylphenyl) -1,3,4-oxadiazole 0.05 parts by mass was heated to 70 ° C. and mixed to obtain a resin composition of the present invention. The viscosity of the composition was 3,200 mPa · s.

Example 2
20 parts by mass of the polyurethane compound (E-2) of Synthesis Example 2, 22 parts by mass of S-1800A (isostearyl acrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., 10 parts by mass of Blenmer LA (lauryl acrylate) manufactured by NOF Corporation, 18 parts by mass of Clearon M-105 (aromatic modified hydrogenated terpene resin) manufactured by Yashara Chemical Co., Ltd .; 10 parts by mass of LV-100 (polybutene) manufactured by JX Nippon Oil & Energy Corporation; GI-2000 manufactured by Nippon Soda Co., Ltd. 20 parts by mass of (1,2-hydrogenated polybutadiene glycol), 0.5 parts by mass of Speed Cure TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide) manufactured by LAMBSON, and IRGACURE 184 (1-hydroxycyclohexylphenyl) manufactured by BASF 0.5 parts by mass of ketone), PBD (2- (4-biphenyl) manufactured by Wako Pure Chemical Industries, Ltd. ) -5- (4-t-butylphenyl) -1,3,4-oxadiazole 0.05 parts by mass was heated to 70 ° C. and mixed to obtain a resin composition of the present invention. The viscosity of the composition was 5000 mPa · s.

Example 3
20 parts by mass of the polyurethane compound (E-3) of Synthesis Example 3, 22 parts by mass of S-1800A (isostearyl acrylate) manufactured by Shin-Nakamura Chemical Co., Ltd., 10 parts by mass of Blenmer LA (lauryl acrylate) manufactured by NOF Corporation, 18 parts by mass of Clearon M-105 (aromatic modified hydrogenated terpene resin) manufactured by Yashara Chemical Co., Ltd .; 10 parts by mass of LV-100 (polybutene) manufactured by JX Nippon Oil & Energy Corporation; GI-2000 manufactured by Nippon Soda Co., Ltd. 20 parts by mass of (1,2-hydrogenated polybutadiene glycol), 0.5 parts by mass of Speed Cure TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide) manufactured by LAMBSON, and IRGACURE 184 (1-hydroxycyclohexylphenyl) manufactured by BASF 0.5 parts by mass of ketone), PBD (2- (4-biphenyl) manufactured by Wako Pure Chemical Industries, Ltd. ) -5- (4-t-butylphenyl) -1,3,4-oxadiazole 0.05 parts by mass was heated to 70 ° C. and mixed to obtain a resin composition of the present invention. The viscosity of the composition was 5,500 mPa · s.

  Examples 1 to 3 are shown in Table 1 and the following evaluations were made.

(viscosity)
It measured at 25 degreeC using E-type viscometer (TV-200: manufactured by Toki Sangyo Co., Ltd.).

(Refractive index)
The refractive index (25 ° C.) of the resin was measured with an Abbe refractometer (DR-M2: manufactured by Atago Co., Ltd.).

(Curing shrinkage)
Prepare two 1 mm-thick slide glasses coated with a fluorine-based release agent, and apply the obtained ultraviolet-curable adhesive composition to one of the release agent-coated surfaces so that the film thickness becomes 200 μm. did. Thereafter, the two slide glasses were stuck so that their release agent-coated surfaces faced each other. The resin composition was irradiated with ultraviolet rays having a cumulative light amount of 3000 mJ / cm ^{2 through} a glass with a high-pressure mercury lamp (80 W / cm, ozone-less) to cure the resin composition. Thereafter, the two slide glasses were peeled off to prepare a cured product for measuring the specific gravity of the film. The specific gravity (DS) of the cured product was measured according to JIS K7112B method. Further, the liquid specific gravity (DL) of the resin composition was measured at 25 ° C. From the measurement results of DS and DL, the cure shrinkage was calculated from the following formula, and found to be less than 2.5%.
Curing shrinkage (%) = (DS-DL) ÷ DS × 100

(Rigidity)
Two release-treated PET films were prepared, and one of the release surfaces was coated with the obtained ultraviolet-curable adhesive composition so as to have a thickness of 200 μm. Thereafter, the two PET films were bonded together such that the release surfaces faced each other. The resin composition was irradiated with ultraviolet light having an integrated light quantity of 3000 mJ / cm ^{2 by} a high-pressure mercury lamp (80 W / cm, ozone-less) through a PET film to cure the resin composition. Thereafter, the two PET films were peeled off to prepare a cured product for measuring the rigidity. The rigidity was measured by ARES (manufactured by TA Instruments).

(Transmissivity)
Two 1 mm-thick slide glasses were prepared, and one of them was coated with the obtained ultraviolet-curable adhesive composition so that the film thickness after curing became 200 μm. Thereafter, two slide glasses were bonded. The resin composition was irradiated with ultraviolet rays of 3000 mJ / cm ^{2 by} a high-pressure mercury lamp (80 W / cm, ozone-less) through glass to cure the resin composition and produce a cured product for transmittance measurement. About the transparency of the obtained hardened | cured material, the transmittance | permeability in the wavelength region of 400-800 nm and 400-450 nm was measured using the spectrophotometer (U-3310, Hitachi High-Technologies Corporation). As a result, the transmittance at 400 to 800 nm was 90% or more, and the transmittance at 400 to 450 nm was 90% or more.

(Heat and moisture resistant adhesion)
Prepare a 1 mm thick slide glass and a 1 mm thick glass plate, or a 1 mm thick glass plate with a polarizing film attached to one side, and apply the resulting ultraviolet-curable adhesive composition to a thickness of 200 μm. After the application, the other was bonded to the application surface. The resin composition was irradiated with ultraviolet light having an integrated light amount of 3000 mJ / cm ^{2 through} a glass with a high-pressure mercury lamp (80 W / cm, ozone-less), and the resin composition was cured to prepare an adhesive evaluation sample. Using this, a heat resistance test at 85 ° C. and a humidity resistance test at 60 ° C. and 90% RH were carried out and left for 100 hours. In the evaluation sample, peeling of the cured resin from the glass or polarizing film was visually confirmed, but no peeling was observed.

Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application (2014-120621) filed on June 11, 2014, which is incorporated by reference in its entirety. Also, all references cited herein are incorporated in their entirety.

  The ultraviolet-curable adhesive composition containing the polyurethane compound of the present invention has excellent flexibility, high weather resistance, high light resistance, and excellent transparency, and thus is useful as an optical member. Further, the cured product of the ultraviolet-curable adhesive composition of the present invention is useful as an adhesive for bonding a transparent display substrate.

Claims (12)

Compound represented by the following (A) and the compound (B), seen containing a compound (C) and the compound (D) a polyurethane compound obtained by reacting (E),
An ultraviolet-curable adhesive composition for a touch panel , wherein the molar ratio (A: D) of the compound (A) and the compound (D) is 9.999: 0.001 to 4: 6 .
Compound (A): hydrogenated polybutadiene polyol compound Compound (B): polyisocyanate compound Compound (C): (meth) acrylate compound having at least one or more hydroxyl group Compound (D): polyether diol compound   The ultraviolet curable adhesive composition for a touch panel, comprising the polyurethane compound (E) according to claim 1, wherein the hydrogenated polybutadiene polyol compound (A) has an iodine value of 20 or less.   An ultraviolet-curable adhesive composition for a touch panel, comprising the polyurethane compound (E) according to claim 1 or 2, wherein the polyisocyanate compound (B) is an aliphatic diisocyanate compound.   The (meth) acrylate compound (C) having at least one or more hydroxyl groups is 2-hydroxyethyl (meth) acrylate, which comprises the polyurethane compound (E) according to any one of claims 1 to 3. UV curable adhesive composition for touch panels. The polyurethane compound (E) according to any one of claims 1 to 4, wherein the polyether diol compound (D) is polyethylene glycol, polybutylene glycol, polytetramethylene glycol, or polypropylene glycol. UV curable adhesive composition for touch panels.   An ultraviolet-curable adhesive composition for a touch panel, comprising the polyurethane compound (E) according to any one of claims 1 to 5 and a polymerizable compound (F) other than (E).   The ultraviolet-curable adhesive composition for a touch panel according to claim 6, wherein the polymerizable compound (F) is an alkyl (meth) acrylate or an alkylene (meth) acrylate.   The ultraviolet-curable adhesive composition for a touch panel according to any one of claims 1 to 7, wherein the polyurethane compound (E) is contained in the ultraviolet-curable composition in an amount of 5% by mass or more.   The ultraviolet-curable adhesive composition for a touch panel according to any one of claims 1 to 8, further comprising a softening component (G).   The ultraviolet-curable adhesive composition for a touch panel according to claim 9, wherein the softening component (G) contains one or both of a hydroxyl group-containing polymer and a terpene-based resin.   A cured product obtained by irradiating the ultraviolet-curable adhesive composition for a touch panel according to claim 1 with an active energy ray.   A touch panel comprising the ultraviolet-curable adhesive composition for a touch panel according to claim 1.