TWI649389B - Ultraviolet-curable adhesive composition, method for producing ultraviolet-curable adhesive sheet, and method for producing laminated body - Google Patents

Abstract

The problem to be solved by the present invention is to provide a UV-curable adhesive composition, which can obtain a UV-curable adhesive sheet excellent in level followability and shape retention, and can provide the UV-curable adhesive sheet. The cured product layer obtained by ultraviolet irradiation is excellent in moist heat whitening resistance. The present invention provides a UV-curable adhesive composition, which is characterized by containing a urethane resin (A) having a hydroxyl group and a (meth) acrylfluorenyl group, a polyisocyanate crosslinking agent (B), and two The (meth) acrylic compound (C) of the above (meth) acrylfluorenyl group, the organic solvent (D), and the photopolymerization initiator (E). The present invention also provides a method for producing an ultraviolet-curable adhesive sheet, which is obtained by applying the ultraviolet-curable adhesive composition to a substrate and drying the organic solvent (D).

Description

Ultraviolet-curable adhesive composition, method for producing ultraviolet-curable adhesive sheet, and method for producing laminated body

The present invention relates to a UV-curable adhesive composition. The UV-curable adhesive composition can be suitably used in the manufacture of IT-related products.

A touch panel is provided in a mobile terminal such as a smart phone or a tablet. The touch panel is composed of a laminated body of a protective glass, an electrode glass / film, and a liquid crystal panel. , Hereinafter referred to as "OCA".) Fixed. A decorative layer is provided on the protective glass in the smart phone, and a height difference of about 20 μm will be formed. Therefore, the OCA must adhere to the protective glass in a state of following the height difference (without involving air bubbles, etc.).

In recent years, the design of smart phones has improved and the decorative layer has increased to about 60 μm. In addition, the tablet computer has a large screen and therefore has a large distortion. For OCA requirements, it can follow a larger level difference and distortion performance. Especially from a design point of view, it is necessary to be able to follow a large level difference without thickening the OCA.

The ultraviolet-curable adhesive composition which can be used for the above OCA, for example, an adhesive obtained by using a solventless adhesive composition containing urethane acrylate, an acrylic monomer, and a photopolymerization initiator is known. (For example, refer to Patent Document 1).

However, in the method of imparting flexibility by reducing the cross-linking density of the resin like the above-mentioned adhesive, although the followability of the level difference becomes good, if the adhesive is excessively soft, it may be caused by flow when the temperature is raised. Entrainment of air bubbles, protrusion of adhesive, non-uniformity of film thickness, etc. Therefore, it is difficult to balance the performance of the difference in level followability and shape retention.

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2006-104296

The problem to be solved by the present invention is to provide a UV-curable adhesive composition, which can obtain a UV-curable adhesive sheet excellent in level followability and shape retention, and can provide the UV-curable adhesive sheet. The cured product layer obtained by ultraviolet irradiation is excellent in moist heat whitening resistance.

The present invention provides a UV-curable adhesive composition, which is characterized by containing a urethane resin (A) having a hydroxyl group and a (meth) acrylfluorenyl group, a polyisocyanate crosslinking agent (B), and two The (meth) acrylic compound (C) of the above (meth) acrylfluorenyl group, the organic solvent (D), and the photopolymerization initiator (E).

The present invention also provides a method for producing an ultraviolet-curable adhesive sheet, which is obtained by applying the ultraviolet-curable adhesive composition to a substrate and drying the organic solvent (D).

Furthermore, the present invention provides a method for manufacturing a laminated body, which is characterized in that at least two adherends are adhered by the above-mentioned ultraviolet-curable adhesive sheet, and then obtained by ultraviolet irradiation.

The ultraviolet-curable adhesive composition of the present invention is a UV-curable adhesive sheet which can be used in combination with thermal cross-linking and ultraviolet-curable, and which can provide excellent level followability and shape retention. The cured product layer obtained by irradiating the ultraviolet-curable pressure-sensitive adhesive sheet with ultraviolet rays has excellent moist heat whitening resistance.

Therefore, the ultraviolet-curable adhesive composition of the present invention can be suitably used as an ultraviolet-curable adhesive composition used in optical members, and can be suitably used in particular in touch panels, liquid crystal displays, plasma displays, Manufacture of IT-related products such as organic EL, computers, and mobile phones.

The ultraviolet-curable adhesive composition of the present invention contains a urethane resin (A) having a hydroxyl group and a (meth) acrylfluorenyl group, a polyisocyanate crosslinking agent (B), and two or more (Meth) acrylic acid (meth) acrylic compound (C), organic solvent (D), and photopolymerization initiator (E).

The urethane resin (A) is one having a hydroxyl group and a (meth) acrylfluorene group. When the organic solvent (D) is dried, the hydroxyl group is thermally crosslinked with a polyisocyanate crosslinking agent (B) described later, and can be visualized. Excellent shape retention and moderate flexibility before UV curing. Therefore, even if it is bonded to a substrate with a level difference, it can follow the level difference without involving air bubbles. Furthermore, this (meth) acrylfluorenyl group is crosslinked with the (meth) acrylic compound (C) mentioned later by ultraviolet irradiation, and since crosslinking density increases, it can express the outstanding moist-heat whitening resistance.

The urethane resin (A) can be used, for example, by reacting a polyol (a1), a polyisocyanate (a2), and a (meth) acrylic compound (a3) having a hydroxyl group or an isocyanate group under conditions where the hydroxyl group becomes excessive. And the winner.

The polyol (a1) may be, for example, a polyether polyol, a polycarbonate polyol, a polyester polyol, a polybutadiene polyol, a hydrogenated polybutadiene polyol, a polyacrylic acid polyol, or a dimer. Alcohols, polyisoprene polyols, etc. These polyols can be used alone or in combination of two or more. Among them, from the viewpoint of obtaining excellent moist-heat whitening resistance due to its skeleton, it is preferable to contain a polyether polyol and / or a polycarbonate polyol.

As the polyether polyol, for example, polyoxyethylene polyol, polyoxypropylene polyol, polyoxytetramethylene polyol, polyoxyethylene polyoxypropylene polyol, polyoxyethylene polyoxytetramethylene polyol can be used. , Polyoxypropylene polyoxytetramethylene polyol and so on. These polyether polyols can be used alone or in combination of two or more. Among them, from the viewpoint of further improving the moist-heat whitening resistance and softness, one type selected from the group consisting of polyoxyethylene polyol, polyoxypropylene polyol, and polyoxytetramethylene polyol is used. The above polyether polyols are preferred.

As the polycarbonate polyol, for example, a polyol obtained by reacting a carbonate and / or phosgene with a compound having two or more hydroxyl groups can be used.

Examples of the carbonate include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclic carbonate, and diphenyl carbonate. These carbonates can be used alone or in combination of two or more.

In addition, as the compound having two or more hydroxyl groups, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, tripropylene glycol, 1 2,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6 -Hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-decadiol Monoalkanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl Aliphatic polyhydric alcohols such as 1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol; 1,2-cyclobutanediol, Alicyclic polyhydric alcohols such as 1,3-cyclopentanediol, 1,4-cyclohexanedimethanol, cycloheptanediol, cyclooctanediol, and hydroxypropylcyclohexanol; bisphenol A, bisphenol F, Aromatic polyols such as 4,4'-biphenol. These compounds can be used singly or in combination. On and use. Among them, from the viewpoint of further improving cutting properties (no adhesive residue at the time of cutting), it is preferable to use an aliphatic polyol and / or an alicyclic polyol, and to use a material selected from the group consisting of 1,4-butane One or more compounds in the group consisting of diol, 1,5-pentanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol are more preferable.

The number average molecular weight of the above-mentioned polyol (a1) is in the range of 500 to 7,000 from the viewpoint of further improving the moisture and heat whitening resistance, softness, and mechanical strength, and further improving the balance between the difference in level followability and shape retention. Preferably, the range of 700 to 4,000 is more preferable, and the range of 800 to 3,000 is more preferable. The number average molecular weight of the polyol (a1) represents a value measured under the following conditions using a gel permeation chromatography (GPC) method.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)

Tubular string: The following tubing columns made by TOSOH Co., Ltd. are used in series connection.

`` TSKgel G5000 '' (7.8mm I.D. x 30cm) x 1

`` TSKgel G4000 '' (7.8mm I.D. x 30cm) x 1

`` TSKgel G3000 '' (7.8mm I.D. x 30cm) x 1

`` TSKgel G2000 '' (7.8mm I.D. x 30cm) x 1

Detector: RI (Differential Refractometer)

Column temperature: 40 ℃

Eluent: tetrahydrofuran (THF)

Flow rate: 1.0mL / min

Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)

Standard samples: Calibration curves were generated using the following standard polystyrene.

(Standard polystyrene)

"TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation

"TSKgel Standard Polystyrene A-1000" made by Tosoh Corporation

"TSKgel Standard Polystyrene A-2500" made by Tosoh Corporation

"TSKgel Standard Polystyrene A-5000" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-1" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-2" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-4" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-10" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-20" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-40" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-80" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-128" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-288" made by Tosoh Corporation

"TSKgel Standard Polystyrene F-550" made by Tosoh Corporation

The above-mentioned polyol (a1) may be used in combination with a chain extender having a number average molecular weight in the range of 50 to 400, if necessary.

The said chain extender can use the thing similar to the compound which has two or more hydroxyl groups used for the raw material of the said polycarbonate polyol, for example. Among them, a moderate chain can be introduced into the urethane resin (A). It has a long hard segment chain, and from the viewpoint of obtaining very excellent shape retention and moist-heat whitening resistance, it is selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, and 1,6 -Hexylene glycol and 1,4-cyclohexanedimethanol are more preferably one or more compounds in the group.

When the above-mentioned chain extender is used, a range of 3 to 50% by mass in the polyol (a1) is preferable, and a range of 5 to 20% by mass is more preferable.

Examples of the polyisocyanate (a2) include aromatic polyisocyanates such as xylylene diisocyanate, benzene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate; hexamethylene diisocyanate, and amines. Fatty acids such as acid diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate Family or alicyclic polyisocyanate and the like. These polyisocyanates can be used alone or in combination of two or more. Among them, from the viewpoint of further improving mechanical strength, adhesive properties, and transparency, it is preferable to use an alicyclic polyisocyanate, and to use a compound selected from 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate. One or more types of polyisocyanate in the group consisting of cyclohexane diisocyanate and methyl isocyanate diisocyanate are more preferred.

The (meth) acrylic compound (a3) having a hydroxyl group or an isocyanate group is used for the purpose of introducing a (meth) acrylfluorenyl group into the urethane resin (A).

In the present invention, "(meth) acrylic group" means an acrylic group and / or methacrylic group, "(meth) acrylate" means an acrylate and / or methacrylate, and "(meth) acrylic acid" "Methyl" means acrylfluorenyl and / or methacrylfluorenyl.

The (meth) acrylic compound having a hydroxyl group that can be used as the compound (a3), for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3- Hydroxypropyl, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, hydroxyethyl methacrylate, etc. ) Alkyl acrylates; trimethylolpropane di (meth) acrylate, neopentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, etc. (Meth) acrylates; polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, and the like. These compounds may be used alone or in combination of two or more. Among them, from the viewpoints of easiness of raw material acquisition, ultraviolet curability, and adhesive physical properties, it is preferable to use a (meth) alkyl acrylate having a hydroxyl group, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are used. Better.

In addition, as the (meth) acrylic compound having an isocyanate group, which can be used as the compound (a3), for example, 2- (meth) acryloxyethyl isocyanate and 2- (2- (isocyanate) (Meth) acryloxyethoxy) ethyl, 1,1-bis ((meth) acryloxymethyl) ethyl isocyanate, and the like. These compounds may be used alone or in combination of two or more. Among them, from the viewpoint of easiness of obtaining raw materials, 2- (meth) acryloxyethyl isocyanate is preferably used, and from the viewpoint of ultraviolet curability, 2-acrylic acid isocyanate is used. Ethyl ethyl is more preferred.

The method for producing the urethane resin (A) when a (meth) acrylic compound having a hydroxyl group is used as the compound (a3), for example, the polyol (a1) and the ( After the (meth) acrylic compound (a3) is added to the reaction system, the polyisocyanate (a2) is provided, and a method for producing the polyisocyanate (a2) by mixing and reacting. This reaction is preferably carried out at, for example, 20 to 120 ° C for 30 minutes to 24 hours.

When a (meth) acrylic compound having an isocyanate group is used as the above-mentioned compound (a3), a method for producing the urethane resin (A), for example, can be used in the absence of a solvent to combine the polyol (a1) with the polymer Isocyanate (a2) is added and reacted to obtain a urethane prepolymer having a hydroxyl group, and then the (meth) acrylic compound (a3) having an isocyanate group is provided, and a method for producing the mixture by reacting the same. This reaction is preferably carried out at, for example, 20 to 120 ° C for 30 minutes to 24 hours.

The said urethane resin (A) can also be manufactured in presence of the organic solvent (D) mentioned later.

When the urethane resin (A) is produced, the polyol (a1), the polyisocyanate (a2), and the (meth) acrylic compound (a3) react with each other, and the hydroxyl group in the polyol (a1) And the total amount of hydroxyl groups of the (meth) acrylic compound (a3), the total amount of isocyanate groups of the polyisocyanate (a2) and the isocyanate groups of the (meth) acrylic compound (a3) When the equivalent ratio [isocyanate group / hydroxyl] is performed within a range of 0.75 to 1, the molecular weight of the urethane resin (A) to be obtained is preferably controlled, and the range of 0.79 to 0.995 is more preferable. In addition, the reaction may be performed when the equivalent ratio is greater than 1. However, in this case, in order to deactivate the isocyanate group of the urethane resin (A), 1,2-propanediol and 1,3-butane are used. Alcohols and the like are preferably bifunctional alcohols composed of primary and secondary hydroxyl groups. At this time, adjust the The equivalent ratio of the total amount of the hydroxyl group of the polyol (a1), the hydroxyl group of the (meth) acrylic compound (a3), and the hydroxyl group of the alcohol to the aforementioned polyisocyanate group [total amount of isocyanate group / hydroxyl ], So that it is preferable to make it into the said range.

Moreover, the alcohol which can be used for the purpose of deactivating the isocyanate group of the said urethane resin (A), For example, you may use together monofunctional alcohols, such as methanol, ethanol, propanol, and butanol.

In the production of the urethane resin (A), a polymerization inhibitor, a urethane catalyst, or the like may be used if necessary.

As the polymerization inhibitor, for example, 3,5-bis-tertiary-butyl-4-hydroxytoluene, hydroquinone, methylhydroquinone, hydroquinone monomethyl ether (methoquinone), and p-tertiary butadiene can be used. Catechol methoxyphenol, 2,6-bis (tertiary butyl) cresol, phenothiazine , Tetramethylthiuram disulfide, diphenylamine, dinitrobenzene, etc. These polymerization inhibitors may be used alone or in combination of two or more.

As the urethane catalyst, for example, triethylamine, triethylenediamine, and N-methyl can be used. Nitrogen-containing compounds such as phospholine; metal salts such as potassium acetate, zinc stearate, and tin octoate; organometallic compounds such as dibutyltin laurate and tetrakis (ethylacetoacetone) zirconium. These urethane catalysts can be used alone or in combination of two or more.

The content of the hydroxyl groups in the urethane resin (A) is based on the viewpoint that shape retention and level difference followability can be obtained by good thermal cross-linking, and moist heat whitening resistance can be maintained at a high level. A range of 0.01 to 0.5 mol / kg is preferable, and a range of 0.02 to 0.2 mol / kg is more preferable.

The content of the (meth) acryl fluorenyl group in the urethane resin (A) is to obtain moist heat and whitening resistance through good ultraviolet curing, and maintain the shape retention and level followability at a high level. From a viewpoint, a range of 0.005 to 0.5 mol / kg is preferable, and a range of 0.01 to 0.2 mol / kg is more preferable.

The mass ratio of the urethane bond in the urethane resin (A) is urethane from the viewpoint that good cutting properties, adhesion properties, and heat and whitening resistance can be obtained by hydrogen bonding. In the resin (A), a range of 4 to 20% by mass is preferable, and a range of 5 to 15% by mass is more preferable. In addition, the urethane bond amount of the urethane resin (A) represents the urethane bond structure in the raw material relative to the total mass of the raw material of the urethane resin (A). Mass ratio.

The weight average molecular weight of the urethane resin (A) is more preferably in the range of 5,000 to 200,000, and more preferably in the range of 15,000 to 100,000, from the viewpoints of adhesive physical properties, shape retention, and step-followability. In addition, the weight average molecular weight of this urethane resin (A) shows the value measured by the method similar to the number average molecular weight of the said polyol (a1).

The polyisocyanate crosslinking agent (B) is a component necessary for thermally crosslinking the hydroxyl group of the urethane resin (A) to obtain an ultraviolet-curable adhesive sheet having excellent shape retention. For example, it can be used. Toluene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate Polyisocyanates such as isocyanate, xylylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate; such trimethylolpropane adducts; such isocyanates Urate body; such biuret bodies and the like. Among them, from the viewpoint that excellent shape retention can be exhibited by three-dimensional cross-linking and that the step-followability can be maintained at a high level, a trimethylolpropane adduct of a polyisocyanate and / or a polyisocyanate are used. An isocyanurate is preferred, and considering the aspect of having a moderate chain length, the polyisocyanate is selected from the group consisting of toluene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, One of the group consisting of diphenylmethane diisocyanate and hydrogenated diphenylmethane diisocyanate is more preferable.

The amount of the polyisocyanate crosslinking agent (B) used is 0.1 to 100 parts by mass of the urethane resin (A) from the viewpoint of crosslinkability with the urethane resin (A). A range of 10 parts by mass is preferable, and a range of 0.2 to 5 parts by mass is more preferable.

The (meth) acrylic compound (C) having two or more (meth) acrylfluorenyl groups is an essential component for obtaining excellent heat and whitening resistance. For example, ethylene glycol di (meth) acrylate can be used. , Propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, hexanediol di (meth) acrylate, bis (meth) 1,6-hexanediol acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, trimethylol tri (meth) acrylate Propane ester, neopentaerythritol di (meth) acrylate, neopentaerythritol tri (meth) acrylate, neopentaerythritol tetra (meth) acrylate, bis (trihydroxymethyl) di (meth) acrylate Propyl propane) ester, bis (trimethylolpropane) tri (meth) acrylate, bis (trimethylolpropane) tetra (meth) acrylate, dineopentaerythritol di (meth) acrylate, Dineopentaerythritol (meth) acrylate, dineopentaerythritol (meth) acrylate, dinepentyl penta (meth) acrylate Aliphatic polyfunctional (meth) acrylates such as tetraol esters, dipentaerythritol hexa (meth) acrylate, and isocyanurate (2- (meth) acryloxyethyl) esters, etc. Polyfunctional (meth) acrylates with isocyanurate backbones. These (meth) acrylic compounds can be used alone or in combination of two or more. Among them, in consideration of obtaining good ultraviolet curability, imparting moist-heat whitening resistance or moderate hardness, and using an aliphatic polyfunctional (methyl group) from the viewpoint of further improving the balance between step-followability and shape retention. ) Acrylic acid esters and / or polyfunctional (meth) acrylic acid esters having an isocyanurate skeleton are preferred, and they are selected from the group consisting of 1,6-hexanediol di (meth) acrylate and tris (meth) acrylate. Trimethylolpropane acrylate, neopentaerythritol tri (meth) acrylate, neopentaerythritol tetra (meth) acrylate, and isocyanurate (2- (meth) acrylic acid) More preferably, one or more (meth) acrylic compounds in the group consisting of a (meth) ester.

The use amount of the (meth) acrylic compound (C) is 100% higher than the urethane resin (A) 100 from the viewpoint of further improving the balance between moist heat and whitening resistance, and step-followability and shape retention. The range of 1 to 50 parts by mass is preferable, and the range of 3 to 40 parts by mass is more preferable.

Examples of the organic solvent (D) include toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, hexane, acetone, cyclohexanone, 3-pentanone, acetonitrile, propionitrile, isobutyronitrile, valeronitrile, and dimethyl. Alkylidene, dimethylformamide and the like. These organic solvents are used alone or in combination of two or more.

The use amount of the organic solvent (D) is more preferably 80% by mass or less, and more preferably 5 to 70% by mass in the viewpoint of further improving drying properties and coatability.

The said photopolymerization initiator (E) is a radical which generate | occur | produces by light irradiation, heating, etc., and initiates the radical polymerization of the said urethane resin (A).

The photopolymerization initiator (E) may be, for example, 4-phenoxydichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 4- (2-hydroxyethoxy) -phenyl (2 -Hydroxy-2-propyl) ketone, 2-methyl- [4- (methylthio) phenyl] -2-olinyl-1-acetone, 2,2-dimethoxy-2-phenylbenzene Acetophenone compounds such as ethyl ketone; benzoin compounds such as benzoin, benzoin methyl ether, benzoin ether, benzoin isopropyl ether, benzoin isobutyl ether; benzophenone, benzophenyl benzoic acid, methyl benzyl benzoate , 4-phenylbenzophenone, hydroxybenzophenone, 4-benzylidene-4'-methyldiphenylsulfide, 3,3'-dimethyl-4-methoxydiphenyl Benzophenone compounds such as ketone; thioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, 2 Thioxanthone compounds such as 1,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone; 4,4'-dimethylaminothioxanthone (alias = Mignonone), 4,4'-diethylamino dibenzoyl , Anthraquinone compounds such as α-fluorenyl oxime ester, diphenylethylenedione, methyl benzoate ("Vicure 55"), 2-ethylanthraquinone; (2,4,6-trimethylbenzene Formamidine) diphenylphosphine oxide, bis (2,4,6-trimethylbenzylidene) -phenylphosphine oxide and other fluorenyl phosphine oxide compounds; 3,3 ', 4,4'-tetra ( Tertiary butyl peroxycarbonyl) benzophenone, acrylated benzophenone and the like. These photopolymerization initiators can be used alone or in combination of two or more.

The photopolymerization initiator (E) is selected from the group consisting of 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1- Hydroxycyclohexylphenyl ketone, (2,4,6-trimethylbenzyl) diphenylphosphine oxide and bis (2,4,6-trimethylbenzyl) -benzene One or more kinds of photopolymerization initiators in the group composed of phosphinophosphine oxide are preferred, and (2,4,6-trimethylbenzylidene) diphenylphosphine oxide is more preferred.

The use amount of the photopolymerization initiator (E) is preferably in a range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the (meth) acrylic compound (C), from the viewpoint of further improving the hardenability, 0.05 to A range of 5 parts by mass is more preferred, and a range of 0.05 to 1 part by mass is particularly preferred.

The ultraviolet-curable adhesive composition of the present invention may contain other additives if necessary.

As the other additives, for example, a silane coupling agent, an antioxidant, a light stabilizer, a rust inhibitor, a thixotropic agent, a sensitizer, a polymerization inhibitor, a leveling agent, a tackifier, an antistatic agent, and a flame retardant can be used. Wait. These additives may be used alone or in combination of two or more. Among them, when the ultraviolet-curable adhesive composition of the present invention is used for applications requiring high adhesive physical properties after resistance to moisture and heat, it is preferable to contain a silane coupling agent. In addition, when the ultraviolet-curable adhesive composition of the present invention is used in applications requiring high resistance to heat, heat and yellowing, it is preferable to contain an antioxidant and a light stabilizer.

Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldioxane. Silane coupling agents with epoxy groups, such as ethoxysilane, 3-glycidoxypropylmethyldimethoxysilane; 2- (3,4-epoxycyclohexyl) ethyltriethoxy Silyl, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, 2- (3 , 4-epoxycyclohexyl) ethylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) propyltrimethoxysilane, 2- (3,4-epoxy ring Hexyl) propyl Methyldimethoxysilane, 2- (3,4-epoxycyclohexyl) propyltriethoxysilane, 2- (3,4-epoxycyclohexyl) propylmethyldiethoxy Silane coupling agents with alicyclic epoxy groups, such as silane; vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 3-methacrylic acid Oxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryl Ethoxypropyltriethoxysilane, 3-propenyloxypropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, siloxane Oxy oligomers, etc. These silane coupling agents can be used alone or in combination of two or more. Among them, from the viewpoint of further improving the adhesion after moist heat resistance, it is preferable to use a silane coupling agent having an epoxy group and / or a silane coupling agent having an alicyclic epoxy group. (3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxy More than one type of silane coupling agent in the group consisting of silane and 3-glycidoxypropyltriethoxysilane is more preferred.

The amount of the silane coupling agent used is preferably in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the urethane resin (A) from the viewpoint of further improving the adhesive force after resistance to moisture and heat. A range of 0.05 to 5 parts by mass is more preferred, and a range of 0.05 to 1 part by mass is particularly preferred.

As the antioxidant, a hindered phenol compound (primary antioxidant) that captures free radicals generated by thermal degradation, a phosphorus compound that decomposes peroxide generated by thermal degradation, a sulfur compound (secondary antioxidant), and the like can be used.

As the hindered phenol compound, for example, bis [3- (3-tertiarybutyl-5-methyl-4hydroxyphenyl) propionic acid] triethylene glycol ester, or [3- (3,5-di-tri Butyl-4-hydroxyphenyl) propionic acid] neopentaerythritol ester, [3- (3,5-di-tertiary butyl-4-hydroxyphenyl) propionic acid] octadecyl ester, thio Bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] divinyl ester, phenylpropionic acid-3,5-bis (1,1-dimethylethyl)- 4-hydroxy-C ₇ -C ₉ side-chain alkyl esters, 4,6-bis (dodecylthiomethyl) -o-cresol, N-phenylaniline and 2,4,4-trimethylpentene Reaction product, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 3,9-bis [2- [3- (Tri-butyl-4-hydroxy-5-methylphenyl) propanyloxy] -1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro [5 .5] undecane, 2,6-di-tertiary-butyl-4-methylphenol, 2,2'-methylenebis (4-methyl-6-tertiary-butylphenol), 2, 5-di-tertiary amyl hydroquinone and the like. These compounds may be used alone or in combination of two or more.

As the phosphorus compound, for example, triphenylphosphine, ethylbis (2,4-di-tert-butyl-6-methylphenyl) phosphite, triphenylphosphite, and nonanylbenzenephosphite can be used. Ester, Phosphite (2,4-dibutylphenyl), Phosphite (2,4-dibutyl-5-methylphenyl), Phosphite [2-tert-butyl- 4- (3-butyl-4-hydroxy-5-methylphenylthio) -5-methylphenyl] ester, ginseng (2,4-di-tert-butylphenyl) phosphite, Tridecyl phosphate, octyl diphenyl phosphite, bis (decyl) monophenyl phosphite, bis (tridecyl) dipentaerythritol diphosphite, bis (nonylphenyl) diphosphite ) Neopentaerythritol ester, bis (2,4-dibutylphenyl) diphosphite, bis (2,6-dibutyl-4-methylphenyl) neopentyl diphosphite Tetraol ester, bis (2,4,6-tributylphenyl) diphosphite, neopentaerythritol diphosphite, bis (2,4-dicumylphenyl) dipentaerythritol diphosphite, Tetrakis (tridecyl) isopropylidene diphenol diphosphite, tetrakis (tridecyl) diphosphite-4,4'-n-butylenebis (2-butyl-5-methylphenol) Ester, hexa (tridecyl) triphosphite, 1,1,3-ginseng (2-methyl-4-hydroxy-5-butylbenzene Phenyl) butane ester, diphosphonic acid (2,4- Dibutylphenyl) biphenylene ester, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis (4,6- Butylphenyl) -2-ethylhexyl ester, 2,2'-methylenebis (4,6-butylphenyl) -octadecyl phosphite, 2,2'-phosphite Ethyl bis (4,6-dibutylphenyl) ester, ginseng (2-[(2,4,8,10-butylbutyl dibenzo [d, f] [1,3,2] dioxin Phosphocycloheptane-6-yl) oxy] ethyl) amine, phosphite esters of 2-ethyl-2-butylpropanediol and 2,4,6-tributylphenol, and the like. These compounds may be used alone or in combination of two or more.

As the sulfur compound, for example, 3,3'-thiopropionate di (dodecyl) ester, 3,3'-thiodipropionate di (dodecyl) ester, and thiodisulfate ten can be used. Dialkyl ester, 3,3'-thiodipropionate di (tridecyl) ester, 3,3'-thiodipropionate di (tetradecyl) ester, 3,3'-thiodi Di (octadecyl) propionate, methylene-methylene-3-dodecyl thiopropionate, bis (octadecyl) thiodipropionate-3,3 '-Methyl ester, 3,3'-dodecyl (octadecyl) thiodipropionate, bis [2-methyl-4- (3-n-alkylthiopropionyloxy)- 5-tert-butylphenyl] thioether, β-dodecyl thiopropionate, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 3,3'-thiodi Di (octadecyl) propionate and the like. These compounds may be used alone or in combination of two or more.

Among them, from the viewpoint of further improving the adhesive force and the resistance to moist heat and yellowing, it is preferable to use a phosphorus compound. One or more antioxidants in the group consisting of 6-methylphenyl) ester and ginseng (2,4-di-tert-butylphenyl) phosphite are preferred. Triphenylphosphine and phosphorous acid are used. Ethyl bis (2,4-di-tertiarybutyl-6-methylphenyl) ester is more preferred.

The amount of the antioxidant used is preferably in the range of 0.01 to 10 parts by mass based on 100 parts by mass of the urethane resin (A) from the viewpoint of further improving the resistance to moisture and yellowing.

The light stabilizer is one that captures free radicals generated by photodegradation. For example, a free radical scavenger such as a thiol compound, a thioether compound, or a hindered amine compound; an ultraviolet ray such as a benzophenone compound or a benzoate compound can be used; Absorbent, etc. These light stabilizers can be used alone or in combination of two or more. Among them, from the viewpoint of further improving the resistance to moist heat and yellowing, it is preferable to use a hindered amine compound.

As the hindered amine compound, for example, cyclohexane and N-butyl 2,2,6,6-tetramethyl-4-piperidinamine-2,4,6-trichloro1,3,5- can be used. three Reaction product of 2-aminoethanol, bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) sebacate, 1, A hindered amine compound having an amine ether group, such as a reaction product of 1-dimethylethyl hydrogen peroxide and octane; N-ethylfluorenyl-3-dodecyl-1- (2,2,6,6 -Tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione and other N-acetylfluorinated hindered amine compounds; sebacic acid bis (1,2,2,6,6-pentamethyl- 4-piperidinyl) ester, {[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl} butylmalonate bis (1,2,2,6 , 6-pentamethyl-4-piperidinyl) ester, dimethyl succinate‧1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate N-alkyl hindered amine compounds of malonic acid [{4-methoxyphenyl} methylene] -bis (1,2,2,6,6-pentamethyl-4-piperidinyl) ester Wait. These compounds may be used alone or in combination of two or more.

The amount used when the light stabilizer is used is preferably in the range of 0.01 to 10 parts by mass based on 100 parts by mass of the urethane resin (A) from the viewpoint of further improving the resistance to moisture and yellowing.

The viscosity of the ultraviolet-curable adhesive composition of the present invention is preferably in the range of 500 to 30,000 mPa · s, and more preferably in the range of 1,000 to 20,000 mPa · s from the viewpoints of coatability and workability. The viscosity is a value measured using a B-type viscometer at 25 ° C.

A method for producing the ultraviolet-curable adhesive sheet of the present invention will be described below.

The ultraviolet curing adhesive sheet is obtained by applying the ultraviolet curing adhesive composition to a substrate, drying the organic solvent (D), and then aging if necessary. In the present invention, after the organic solvent (D) is dried, the urethane resin (A) and the polyisocyanate cross-linking agent (B) are thermally cross-linked to obtain an ultraviolet-curing adhesive having excellent shape retention. sheet. When the (meth) acrylic compound (C) contains a hydroxyl group, the polyisocyanate crosslinking agent (B) is thermally crosslinked with the urethane resin (A). Therefore, since ultraviolet rays to be described later can be cured more effectively, it is possible to obtain an ultraviolet curing type adhesive sheet having excellent moist heat whitening resistance.

The method of applying the ultraviolet-curable adhesive composition to a substrate includes, for example, a method of applying using an applicator, a roll coater, a knife coater, a gravure coater, or the like.

The substrate may be, for example, a plastic substrate, a flexible printing substrate, a glass substrate, a substrate obtained by demolding the substrate, or a substrate obtained by vapor-depositing ITO (indium tin oxide). .

The plastic substrate may be, for example, acrylic resin, PC (polycarbonate), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), modified PPE (polyphenylene ether), or PET. (Polyethylene terephthalate Esters), COP (cycloolefin polymer), TAC (triethylammonium cellulose), etc., as raw materials, plastic films, antireflection films, antifouling films, films of transparent conductive films constituting touch panels, and the like.

The method of drying the organic solvent (D) is, for example, a method performed at a temperature of 60 to 120 ° C for 1 minute to 1 hour.

After the drying, the purpose is to further promote thermal crosslinking of the urethane resin (A), the polyisocyanate crosslinking agent (B), and the (meth) acrylic compound (C), and further improve shape retention. For example, it can also be aged for 1 to 7 days at a temperature of 10 to 40 ° C.

The thickness of the ultraviolet-curable pressure-sensitive adhesive sheet is appropriately determined depending on the application, and is, for example, in the range of 10 to 500 μm.

The method for producing the laminated body of the present invention will be described below.

The laminated body is obtained by laminating at least two adherends through the ultraviolet-curable adhesive sheet and then irradiating them with ultraviolet rays.

The above-mentioned adherend, in addition to the above-mentioned substrate, especially when the laminated body of the present invention is used in the manufacture of IT-related products, for example, a touch panel, a liquid crystal module, a protective glass, and a protective glass-touch panel integrated Panel (OGS), etc.

In addition, the end of the adherend may have a step difference due to a black printing layer or the like. Since the ultraviolet-curable adhesive sheet of the present invention has excellent followability of the step, the step portion of the adherend may be different. Leave gaps to stick.

The structure of the laminated body of the present invention used in the manufacture of IT-related products includes, for example, a cured layer of a liquid crystal module / ultraviolet-curable adhesive sheet / touch panel, a liquid crystal module / ultraviolet-cured adhesive sheet Hardened material layer / touch panel / hardened material layer of UV-curable adhesive sheet / protective glass, LCD module / hardened material layer of UV-curable adhesive sheet / OGS, etc.

Examples of the method of the ultraviolet irradiation include a method using a known ultraviolet light irradiating device such as a xenon lamp, a xenon-mercury lamp, a metal halide lamp, a high-pressure mercury lamp, and a low-pressure mercury lamp.

The ultraviolet irradiation amount is 0.05 ~ 5J / cm ² of the preferred range, 0.1 ~ 3J / cm ² more preferably, 0.3 ~ 1.5J / cm ² particularly preferred. In addition, the amount of ultraviolet irradiation is based on a value measured in a wavelength range of 300 to 390 nm using a UV checker "UVR-N1" manufactured by GS Yuasa International Ltd.

After the ultraviolet irradiation, the urethane resin (A) and the (meth) acrylic compound (C) are completely hardened, and the crosslinking density is increased, so that they exhibit excellent moist-heat whitening resistance.

From the viewpoint of further improving the moisture and whitening resistance of the cured product layer of the ultraviolet-curable adhesive sheet, the storage elastic modulus at 30 ° C is preferably 1 × 10 ⁴ Pa or more when measured at a frequency of 1 Hz. The method for measuring the storage elastic modulus of the adhesive sheet is described in Examples.

In addition, from the viewpoint of further improving the moisture and heat whitening resistance of the above-mentioned adhesive sheet, the storage elastic modulus at 80 ° C. and 100 ° C. is preferably 1 × 10 ⁴ Pa or more when measured at a frequency of 1 Hz. The method for measuring the storage elastic modulus of the adhesive sheet is described in Examples.

The ultraviolet-curable adhesive composition of the present invention is one which can be used in combination with thermal cross-linking and ultraviolet curing, and can obtain an ultraviolet-curable adhesive sheet excellent in level followability, shape retention, and cutting properties. In addition, the cured product layer obtained by irradiating the ultraviolet-curable adhesive sheet with ultraviolet rays has excellent moisture-heat whitening resistance and durability.

Therefore, the ultraviolet-curable adhesive composition of the present invention can be suitably used as an ultraviolet-curable adhesive composition used in optical members, and is particularly suitable for use in touch panels, liquid crystal displays, plasma displays, organic Manufacture of IT-related products such as EL, computer and mobile phone.

[Example]

Hereinafter, the present invention will be described in more detail using examples.

[Synthesis Example 1]

<Synthesis of urethane resin solution (A-1)>

To a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, 287 parts by mass of polyoxypropylene glycol (the number average molecular weight is 1,000, hereinafter referred to as "PPG"), 2-hydroxyethyl acrylate, was added. Ester (hereinafter referred to as "HEA") 0.8 parts by mass, 1,4-hexanedimethanol (hereinafter referred to as "CHDM") 31 parts by mass, and 2,6-di (tributyl) cresol 1.1 parts by mass Parts, 0.2 parts by mass of p-methoxyphenol, and 150 parts by mass of ethyl acetate. After the temperature in the reaction vessel was raised to 40 ° C, 110 parts by mass of isophorone diisocyanate (hereinafter referred to as "IPDI") was added. Then, 0.05 mass part of dioctyltin dineodecanoate was added, and it heated up to 75 degreeC over 1 hour. Then, after maintaining at 75 ° C for 12 hours, 136 parts by mass of ethyl acetate was added, followed by stirring for 30 minutes until uniform, and cooled to obtain a non-volatile component of 60% by mass, a weight average molecular weight of 39,000, and a hydroxyl content of 0.032mol / kg, a urethane resin solution (A-1) having a content of acrylyl group of 0.016 mol / kg.

[Synthesis Example 2]

<Synthesis of urethane resin solution (A-2)>

To a reaction vessel equipped with a stirrer, a reflux cooling pipe, a nitrogen introduction pipe, and a thermometer, PPG205 parts by mass, HEA 1.32 parts by mass, CHDM42 parts by mass, and 2,6-di (tributyl) cresol 1.1 parts were added. Parts, 0.2 parts by mass of p-methoxyphenol, and 150 parts by mass of ethyl acetate. After the temperature in the reaction vessel was raised to 40 ° C, 110 parts by mass of IPDI was added. Then, 0.05 mass part of dioctyltin dineodecanoate was added, and it heated up to 75 degreeC over 1 hour. Then, after maintaining at 75 ° C for 12 hours, 89 parts by mass of ethyl acetate was added, followed by stirring for 30 minutes until uniform, and cooled to obtain a nonvolatile component of 60% by mass, a weight average molecular weight of 32,000, and a hydroxyl content of 0.032mol / kg, a urethane resin solution (A-2) having a content of acrylyl group of 0.032 mol / kg.

[Synthesis Example 3]

<Synthesis of urethane resin solution (A-3)>

In a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, 274 parts by mass of polyoxytetramethylene glycol (the number average molecular weight is 1,000, hereinafter referred to as "PTMG"), HEA1. 1 part by mass, 1,4-butanediol (hereinafter referred to as "1,4BG") 20 parts by mass, 1.1 parts by mass of 2,6-bis (tributyl) cresol, and 0.2 part by mass of p-methoxyphenol Parts, 150 parts by mass of ethyl acetate. After the temperature in the reaction vessel was raised to 40 ° C, 109 parts by mass of IPDI was added. Then, 0.05 mass part of dioctyltin dineodecanoate was added, and it heated up to 75 degreeC over 1 hour. Then, after maintaining at 75 ° C for 12 hours, 119 parts by mass of ethyl acetate was added, followed by stirring for 30 minutes until uniform, and cooled to obtain a non-volatile component of 60% by mass, a weight average molecular weight of 35,000, and a hydroxyl content of 0.048mol / kg, a urethane resin solution (A-3) having a content of acrylfluorenyl group of 0.048 mol / kg.

[Synthesis Example 4]

<Synthesis of urethane resin solution (A-4)>

To a reaction vessel equipped with a stirrer, a reflux cooling pipe, a nitrogen introduction pipe, and a thermometer, a polycarbonate polyol ("DURANATE T5651" manufactured by Asahi Kasei Chemicals Co., Ltd.) was added, and the number average molecular weight was 1,000. , Hereinafter referred to as "PC".) 262 parts by mass, 0.75 parts by mass of HEA, 35 parts by mass of CHDM, 1.1 parts by mass of 2,6-bis (tributyl) cresol, 0.2 parts by mass of p-methoxyphenol, acetic acid 150 parts by mass of ethyl ester. After the temperature in the reaction vessel was raised to 40 ° C, 110 parts by mass of IPDI was added. Then, 0.05 mass part of dioctyltin dineodecanoate was added, and it heated up to 75 degreeC over 1 hour. Then, after maintaining at 75 ° C. for 12 hours, 122 parts by mass of ethyl acetate was added, followed by stirring for 30 minutes until uniform, and cooled to obtain a non-volatile component of 60% by mass, a weight average molecular weight of 33,000, The urethane resin solution (A-4) having a content of 0.032 mol / kg and acryl fluorenyl group was 0.016 mol / kg.

[Synthesis Example 5]

<Synthesis of urethane resin solution (A-5)>

To a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, PPG 264.5 parts by mass, HEA 0.6 parts by mass, CHDM 34 parts by mass, and 2,6-di (tributyl) cresol were added. 1.1 parts by mass, 0.2 parts by mass of p-methoxyphenol, and 150 parts by mass of ethyl acetate. After the temperature in the reaction vessel was raised to 40 ° C, 109 parts by mass of IPDI was added. Then, 0.05 mass part of dioctyltin dineodecanoate was added, and it heated up to 75 degreeC over 1 hour. Then, after maintaining at 75 ° C. for 12 hours, 122 parts by mass of ethyl acetate was added, followed by stirring for 30 minutes until uniform, and cooled to obtain a nonvolatile component of 60% by mass, a weight average molecular weight of 19,000, and a hydroxyl content of 0.10 mol / kg, a urethane resin solution (A-5) having a content of acryl fluorenyl group of 0.0125 mol / kg.

[Synthesis Example 6]

<Synthesis of urethane resin solution (A-6)>

To a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, were added PPG286 parts by mass, HEA 1.24 parts by mass, CHDM 30.5 parts by mass, and 2,6-bis (tributyl) cresol. 1.1 parts by mass, 0.2 parts by mass of p-methoxyphenol, and 150 parts by mass of ethyl acetate. After the temperature in the reaction vessel was raised to 40 ° C, 110 parts by mass of IPDI was added. Then, 0.05 mass part of dioctyltin dineodecanoate was added, and it heated up to 75 degreeC over 1 hour. Then, after maintaining at 75 ° C. for 12 hours, 135 parts by mass of ethyl acetate was added, followed by stirring for 30 minutes until uniform, and cooled to obtain a non-volatile component of 60% by mass and a weight average molecular weight of 29,000, a urethane resin solution (A-6) having a hydroxyl group content of 0.025 mol / kg and a propylene methyl group content of 0.025 mol / kg.

[Example 1]

<Preparation of UV-curable adhesive composition>

In a reaction vessel equipped with a stirrer, a reflux cooling tube, and a thermometer, 100 parts by mass of the urethane resin (A-1) and trimethylolpropane triacrylate ("ARONIX" M-309 ″) 10 parts by mass and stir until uniform. Then, it cooled to room temperature, and 0.5 mass part of 1-hydroxy-cyclohexyl-phenyl-one (henceforth "(E-1)"), sebacic acid bis (2,2,6) were sequentially added with stirring. 0.5 parts by mass of 6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) ester and 0.5 parts by mass of triphenylphosphine, and stirred until uniform. Further, 1 part by mass of an isocyanurate body of hexamethylene diisocyanate (HDI) was added, and after stirring until homogeneous, it was filtered through a 200-mesh metal mesh to obtain a UV-curable adhesive composition.

[Examples 2 to 8]

The types of the urethane resin (A) used, the polyisocyanate crosslinking agent (B), and the type and / or amount of the (meth) acrylic compound (C) were changed to those shown in Tables 1 to 2. Except for the kind and / or amount, a UV-curable adhesive composition was obtained by the same method as in Example 1.

[Comparative Example 1]

A UV-curable adhesive composition was obtained by the same method as in Example 1 except that 1 part by mass of the isocyanurate compound of HDI was changed to 0 parts by mass.

[Comparative Example 2]

A UV-curable adhesive composition was obtained by the same method as in Example 1 except that 10 parts by mass of trimethylolpropane triacrylate was changed to 0 parts by mass.

[Method for making UV-curable adhesive sheet]

On the surface of the polyethylene terephthalate film (release PET50) having a thickness of 50 μm, the surface of which was subjected to a mold release treatment, the ultraviolet curable adhesive grease composition obtained in the examples and comparative examples was applied. The film thickness of the organic solvent after drying was 100 μm, and it was dried in a dryer at 80 ° C. for 3 minutes to obtain a UV-curable adhesive sheet.

[Evaluation method of moist heat and whitening resistance]

The ultraviolet-curable adhesive sheet was bonded to a polyethylene terephthalate film (PET100) having a thickness of 100 μm to prepare a laminated body to which PET100 was bonded. It was cut into 50 mm in the longitudinal direction and 40 mm in the transverse direction. Then, ultraviolet rays were irradiated from the glass plate side so that the cumulative light amount of the wavelength in the UV-A range after passing through the glass plate was 1 J / cm ² to obtain a laminate having an adhesive sheet as a test piece. The haze (%) of this test piece was measured using a turbidimeter "NDH5000" (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7361-1-1997. Then, the obtained test piece was left for 100 hours under the conditions of 85 ° C. and 85% RH (hereinafter referred to simply as “after the moist heat resistance test”), and then taken out in an environment of 23 ° C. and 50% RH. After taking out, the haze (%) was measured using a turbidimeter "NDH5000" (manufactured by Nippon Denshoku Kogyo Co., Ltd.) within 10 minutes in accordance with JISK7361-1-1997. Evaluation.

"○": The difference in the haze (%) values before and after the moist heat resistance test is less than 0.3%.

"△": The difference in the haze (%) values before and after the moist heat resistance test is 0.3% or more and less than 1.0%.

"×": The difference in haze (%) values before and after the moist heat resistance test is 1% or more.

[Method for evaluating shape retention]

The laminate produced in the above [Evaluation Method of Moisture and Whitening Resistance] was cut to 25 mm × 25 mm, and the PET film on both sides was replaced with a PET film cut to a size of 40 mm × 40 mm as a test. sheet. The obtained test piece was sandwiched between glass plates, a weight of 5 kg was put, and it was left to stand at 40 ° C. for 1 hour. Then, the ratio of the area of the adhesive sheet after the placement to the area of the adhesive sheet before the placement (25 mm × 25 mm = 625 mm ² ) was calculated, and the evaluation of the shape retention was evaluated in the following manner.

"○": The area magnification of the adhesive sheet after placement was less than 103%.

"△": The area magnification of the adhesive sheet after being placed was 103% or more and less than 105%.

"×": The area magnification of the adhesive sheet after being placed is 105% or more.

[Evaluation method of followability of level difference]

The ultraviolet-curable adhesive sheet was bonded to a polyethylene terephthalate film (PET100) having a thickness of 100 μm to prepare a laminated body having PET100 bonded on one side. The test piece was cut into 50 mm in the longitudinal direction and 40 mm in the transverse direction. In addition, a frame having a length of 40 mm, a width of 30 mm, and a width of 5 mm was cut from PET50. The frame having a thickness of 50 μm was placed on a glass plate, and the test piece was pressed back and forth with 2 kg rollers twice, so that the frame having a thickness of 50 μm was sandwiched between PET100 and the test piece and adhered. This was subjected to an autoclave treatment at 50 ° C and 0.5 MPa for 20 minutes. Then, ultraviolet rays were irradiated from the glass plate side so that the cumulative light amount of the wavelength in the UV-A range after passing through the glass plate was 1 J / cm ² to obtain a laminate having an adhesive sheet. The obtained laminate was left to stand in an environment of 80 ° C. for 24 hours, and the inner part of the frame having a thickness of 50 μm was visually observed, and the followability of the step difference of 50 μm was evaluated in the following manner.

"○": There is no lifting from the height difference, and there is no mixing of bubbles.

"△": There is no lift from the height difference, and only a few bubbles are mixed.

"×": There was no lifting from the height difference, but the inclusion of bubbles was partially confirmed.

The abbreviations in Tables 1 and 2 will be described.

"Trimethylolpropane adduct of TDI": Trimethylolpropane adduct of toluene diisocyanate

"Trimethylolpropane adduct of XDI": Trimethylolpropane adduct of xylylene diisocyanate

"Mixture of PETA and PETEA": Mixture of neopentyl triacrylate and neopentyl tetraacrylate ("ARONIX M-305" manufactured by Toa Kosei Co., Ltd.)

"1,6-HDDA": 1,6-hexanediol diacrylate

It can be seen that Examples 1 to 8 of the ultraviolet-curable adhesive composition of the present invention are excellent in moist heat whitening resistance, step-followability, and shape retention.

On the other hand, Comparative Example 1 was a state where the polyisocyanate crosslinking agent (B) was not used, and its shape retention was poor.

Comparative Example 2 is a state in which the (meth) acrylic compound (C) is not used, and its moist heat and whitening resistance is inferior, and its level followability is also insufficient.

Claims (9)

A UV-curable adhesive composition comprising a urethane resin (A) having a hydroxyl group and a (meth) acrylfluorenyl group, a polyisocyanate crosslinking agent (B), and two or more ( (Meth) acrylic acid-based (meth) acrylic compound (C), organic solvent (D), and photopolymerization initiator (E); the (meth) acrylic compound (C) is an aliphatic polyfunctional (meth) ) Acrylates and / or polyfunctional (meth) acrylates having an isocyanurate backbone. For example, the ultraviolet curing adhesive composition of the first patent application range, wherein the urethane resin (A) is a polyol (a1) containing a polyether polyol and / or a polycarbonate polyol as Raw materials. For example, the ultraviolet curable adhesive composition of the first patent application range, wherein the content of hydroxyl groups in the urethane resin (A) is in the range of 0.01 to 0.5 mol / kg. For example, the ultraviolet curable adhesive composition according to the first patent application range, wherein the content of the (meth) acrylfluorenyl group in the urethane resin (A) is in the range of 0.005 to 0.5 mol / kg. For example, the ultraviolet curable adhesive composition according to the first patent application range, wherein the polyisocyanate crosslinking agent (B) is a trimethylolpropane adduct of polyisocyanate and / or isocyanuric acid of polyisocyanate Ester. For example, the ultraviolet curable adhesive composition according to the first patent application range, wherein the amount of the polyisocyanate crosslinking agent (B) used is 100 parts by mass relative to 100 parts by mass of the solid content of the urethane resin (A). The range is from 0.1 to 10 parts by mass. For example, the ultraviolet curing adhesive composition of the first patent application range, wherein the amount of the (meth) acrylic compound (C) used is 100 parts by mass relative to the solid content of the urethane resin (A). The range is 1 to 50 parts by mass. A method for manufacturing an ultraviolet-curable adhesive sheet, characterized in that an organic solvent (D) is coated on a substrate after the ultraviolet-curable adhesive composition according to any one of claims 1 to 7 is applied to a substrate. Obtained by drying. A method for manufacturing a laminated body, which is characterized in that at least two adherends are adhered by an ultraviolet curing adhesive sheet such as the item No. 8 of the patent application scope, and then obtained by ultraviolet irradiation.