JP6720518B2 - Active energy ray curable polyurethane adhesive sheet, article and information display device - Google Patents

Description

The present invention relates to an active energy ray-curable polyurethane adhesive sheet that can be used in various fields including the optical field.

Information display devices such as a liquid crystal display (LCD) and an organic EL display are various devices including a mobile electronic terminal such as an electronic notebook, a mobile phone, a smartphone, a mobile audio player, a personal digital assistant (PDA), and a tablet terminal. Used in.
The information display device mounted on the portable electronic terminal or the like is required to have a characteristic that can correspond to further downsizing and thinning of the portable electronic terminal and can display high-definition information.

As the information display device, for example, an information display device is known in which a transparent panel for protecting the LCD module, the organic EL module, and the like is provided above the LCD module and the organic EL module. Usually, the transparent panel (protection panel) and the information display module are usually fixed by a highly transparent adhesive sheet.

Conventionally, a glass panel has been used as the protective panel, but in recent years, a panel made of a resin film, a resin plate or the like has been increasingly used in order to reduce the weight of electronic devices.

However, when a resin film or the like is used as a protective panel, gas such as gas or water may be generated from the resin film or the like under a humid heat environment. If it forms bubbles at the interface between the resin film or the like and the pressure-sensitive adhesive sheet, peeling at the interface or deterioration of the sharpness of displayed information may occur.

As an adhesive tape that can be used for fixing the protective panel and the information display module, for example, one surface of a base material having a predetermined thickness has a predetermined loss tangent that is attached to a transparent panel provided with a decorative portion. A double-sided pressure-sensitive adhesive tape for fixing panels, which has an acrylic pressure-sensitive adhesive layer and has an acrylic pressure-sensitive adhesive layer having a predetermined loss tangent that is attached to the surface of the image display device on the other surface of the base material, is known ( For example, see Patent Document 1).

However, in the pressure-sensitive adhesive tape, the gas generated from the resin film or the like in a moist heat environment still forms bubbles at the interface between the resin film and the pressure-sensitive adhesive tape, resulting in interface peeling and clearness of displayed information. In some cases, it caused a decrease.

JP, 2013-001769, A

The problem to be solved by the present invention is to prevent the formation of air bubbles at the interface between the adherend and the adhesive sheet, thereby preventing the interfacial peeling of the adherend and the excellent transparency. Is to provide a sheet.

The present invention provides an active energy ray-curable polyurethane adhesive sheet having an adhesive layer (A) having a storage elastic modulus (G′ _A100 ) of less than 1×10 ⁵ Pa measured at a temperature of 100° C. and a frequency of 1 Hz. The storage elastic modulus (G′ _A′100 ) measured at a temperature of 100° C. and a frequency of 1 Hz of the layer (A′) obtained by curing the adhesive layer (A) is 2×10 ⁵ Pa or more, and the temperature is 60° C. And an active energy ray-curable polyurethane adhesive sheet, which is used for adhering an adherend (b) capable of generating gas when left in an environment of 90% humidity for 24 hours.

The active energy ray-curable polyurethane adhesive sheet of the present invention has excellent adhesion to an adherend. The active energy ray-curable polyurethane adhesive sheet of the present invention is cured by being irradiated with an active energy ray and can prevent bubbles from being formed at the interface between the adhesive sheet and an adherend.

The adhesive sheet of the present invention is an active energy ray-curable polyurethane adhesive sheet having an adhesive layer (A) having a storage elastic modulus (G′ _A100 ) of less than 1×10 ⁵ Pa measured at a temperature of 100° C. and a frequency of 1 Hz. And the storage elastic modulus (G′ _A′100 ) of the layer (A′) obtained by curing the adhesive layer (A) at a temperature of 100° C. and a frequency of 1 Hz is 2×10 ⁵ Pa or more, An active energy ray-curable polyurethane adhesive sheet, which is used for adhering an adherend (b) capable of generating gas when left in an environment of a temperature of 60° C. and a humidity of 90% for 24 hours. The adhesive layer and the adhesive sheet include the concept of a so-called pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) and a pressure-sensitive adhesive sheet (pressure-sensitive adhesive sheet).

The adhesive sheet can achieve both good adhesion and cohesive force with respect to the adherend (b), and forms bubbles due to gas that can be generated from the adherend (b). Can be suppressed.

As the adhesive sheet, a single layer of the adhesive layer (A) or a sheet composed of two or more layers can be used, and a sheet obtained by laminating the adhesive layer (A) and other layers is used. However, it is preferable to use the one composed of the single layer of the adhesive layer (A).

[Adhesive layer (A)]
As the adhesive layer (A), one having a storage elastic modulus (G′ _A100 ) of less than 1×10 ⁵ Pa is used, and one in the range of 5×10 ³ Pa to 8×10 ⁴ Pa is used. It is preferable to use one having a range of 1×10 ⁴ Pa to 7×10 ⁴ Pa, which has more excellent adhesion to the adherend (b), It is more preferable for obtaining an adhesive sheet capable of suppressing the formation of bubbles due to the gas that can be generated from the body (b).

Further, that the storage elastic modulus (G′ _A100 ) of the adhesive layer (A) is less than 1×10 ⁵ Pa means that an adherend having a decorative portion (step portion) is used as the adherend (b). In that case, it is also preferable for obtaining an adhesive sheet having a suitable followability to the decorative portion.

The adhesive layer (A) is irradiated with an active energy ray to form a layer (A′) in which the adhesive layer (A) is cured [hereinafter, a cured layer (A′)].
_{Examples of the} cured layer (A′) include those having the storage elastic modulus (G′ _A′100 ) of 2×10 ⁵ Pa or more, and those in the range of 3×10 ⁵ to 1×10 ⁷ Pa. However, more excellent cohesive force can be imparted, and it is more preferable for suppressing the formation of bubbles due to the gas that can be generated from the adherend (b).

The storage elastic modulus at 100° C. (G′ _A100 ) was measured by using a viscoelasticity tester (trade name: ARES-G2, manufactured by TA Instruments Japan Co., Ltd.). It can be obtained by sandwiching a test piece between certain parallel disks and measuring the storage elastic modulus and loss elastic modulus at a temperature of 100° C. and a frequency of 1 Hz. In addition, as the test piece used in the above measurement, the adhesive layer (A) cut into a circular shape having a thickness of 1 mm and a diameter of 8 mm is used.

The cured layer (A′) formed by irradiation with the active energy ray preferably has a 180° peel adhesion strength of 5 to 50 N/25 mm with respect to a polycarbonate substrate having a smooth surface, and 7 to The range of 30 N/25 mm can suppress the formation of bubbles caused by the gas that can be generated from the adherend (b) and is excellent in reworkability from the adherend (b). It is more preferable for obtaining a sheet.

The gel fraction of the cured layer (A′) formed by irradiating the active energy ray is preferably 75% by mass to 95% by mass, and 80% by mass to 90% by mass. It is more preferable to suppress the formation of bubbles due to the gas that can be generated from the adherend (b).
Gel fraction (mass %)=[(mass of cured layer (A′) after immersion in toluene)/(mass of cured layer (A′) before immersion in toluene]×100

The adhesive layer (A) can be produced, for example, by coating the surface of a release film or the like with an adhesive composition and drying.
As the adhesive composition, for example, an adhesive composition containing a urethane resin (a) having a hydroxyl group and a (meth)acryloyl group can be used.

As the urethane resin (a), for example, a polyol (a1), a polyisocyanate (a2), and a (meth)acrylic compound (a3) having a hydroxyl group or an isocyanate group are reacted under the condition that the hydroxyl group becomes excessive. What is obtained can be used.

As the polyol (a1), for example, polyether polyol, polycarbonate polyol, polyester polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, polyacryl polyol, dimer diol, polyisoprene polyol, etc. can be used. These polyols may be used alone or in combination of two or more. In containing an polyether polyol and/or a polycarbonate polyol, an excellent cohesive force can be imparted, and in order to obtain an adhesive sheet capable of suppressing the formation of bubbles due to the gas that can be generated from the adherend (b). preferable.

Examples of the polyether polyol include polyoxyethylene polyol, polyoxypropylene polyol, polyoxytetramethylene polyol, polyoxyethylene polyoxypropylene polyol, polyoxyethylene polyoxytetramethylene polyol, polyoxypropylene polyoxytetramethylene polyol. Etc. can be used. These polyether polyols may be used alone or in combination of two or more kinds.

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

As the carbonic acid ester, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate or the like can be used. These carbonate esters may be used alone or in combination of two or more kinds.

Examples of the compound having two or more hydroxyl groups include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol. 1,2-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-undecanediol, 1,12-dodecanediol, 2 -Methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol , Aliphatic polyols such as 2-methyl-1,8-octanediol; 1,2-cyclobutanediol, 1,3-cyclopentanediol, 1,4-cyclohexanedimethanol, cycloheptanediol, cyclooctanediol, hydroxypropyl Alicyclic polyols such as cyclohexanol; aromatic polyols such as bisphenol A, bisphenol F, and 4,4′-biphenol can be used. These compounds may be used alone or in combination of two or more.

The number average molecular weight of the polyol (a1) is 500 to 7,000, because excellent cohesive force can be imparted and foaming caused by the gas generated from the adherend (b) can be suppressed. The range is preferable, the range of 700 to 4,000 is more preferable, and the range of 800 to 3,000 is further preferable. The number average molecular weight of the polyol (a1) is a value measured by the gel permeation chromatography (GPC) method under the following conditions.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSK gel G4000" (7.8 mm ID x 30 cm) x 1 "TSK gel G3000" (7.8 mm ID x 30 cm) x 1 This "TSK gel G2000" (7.8 mm ID x 30 cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40°C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
Tosoh Corporation "TSKgel Standard Polystyrene A-500"
Tosoh Corporation "TSK gel standard polystyrene A-1000"
Tosoh Corporation "TSK gel standard polystyrene A-2500"
Tosoh Corporation "TSK gel standard polystyrene A-5000"
"TSK gel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSK gel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSK gel standard polystyrene F-4" manufactured by Tosoh Corporation
Tosoh Corporation "TSK gel standard polystyrene F-10"
Tosoh Corporation "TSK gel standard polystyrene F-20"
Tosoh Corporation "TSK gel standard polystyrene F-40"
Tosoh Corporation "TSK gel standard polystyrene F-80"
Tosoh Corporation "TSK gel standard polystyrene F-128"
Tosoh Corporation "TSK gel standard polystyrene F-288"
Tosoh Corporation "TSK gel standard polystyrene F-550"

As the polyol (a1), a chain extender having a hydroxyl group may be used in combination, if necessary.

As the chain extender having a hydroxyl group, for example, the same compound as the compound having two or more hydroxyl groups can be used.

Examples of the polyisocyanate (a2) include aromatic polyisocyanates such as xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate and naphthalene diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, 4,4 Aliphatic or alicyclic polyisocyanates such as'-dicyclohexylmethane diisocyanate, diisocyanate methylcyclohexane, and tetramethylxylylene diisocyanate can be used. These polyisocyanates may be used alone or in combination of two or more. It is preferable to use an alicyclic polyisocyanate in order to obtain an adhesive sheet capable of imparting excellent cohesive force and capable of suppressing the formation of bubbles due to the gas generated from the adherend (b). It is more preferable to use one or more polyisocyanates selected from the group consisting of 4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate and diisocyanatomethylcyclohexane.

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

In addition, in this invention, "(meth)acryl" shows an acryl and/or methacryl, "(meth)acrylate" shows an acrylate and/or a methacrylate, and "(meth)acryloyl" means acryloyl. And/or methacryloyl.

Examples of the (meth)acrylic compound having a hydroxyl group that can be used as the compound (a3) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and the like. (Meth)acrylic acid alkyl ester having a hydroxyl group such as 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate and hydroxyethylacrylamide; trimethylolpropane di(meth) A polyfunctional (meth)acrylate having a hydroxyl group such as acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate; polyethylene glycol monoacrylate, polypropylene glycol monoacrylate and the like can be used. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use acrylic acid (meth)alkyl ester having a hydroxyl group, from the viewpoints of easy availability of raw materials, ultraviolet curability and adhesive properties, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are used. Is more preferable.

Examples of the (meth)acrylic compound having an isocyanate group that can be used as the compound (a3) include 2-(meth)acryloyloxyethyl isocyanate and 2-(2-(meth)acryloyloxyethyloxy)ethyl. Isocyanate, 1,1-bis((meth)acryloyloxymethyl)ethyl isocyanate or the like can be used. These compounds may be used alone or in combination of two or more. Among these, it is preferable to use 2-(meth)acryloyloxyethyl isocyanate from the viewpoint of easy availability of raw materials, and it is more preferable to use 2-acryloyloxyethyl isocyanate from the viewpoint of ultraviolet curability.

As a 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 (meth)acrylic compound ( It is possible to use a method in which the polyisocyanate (a2) is supplied, mixed and reacted after charging a3) with the reaction system. The reaction is preferably carried out, for example, under conditions of 20°C to 120°C for 30 minutes to 24 hours.

As a method for producing the urethane resin (A) in the case of using a (meth)acrylic compound having an isocyanate group as the compound (a3), for example, the polyol (a1) and the polyisocyanate (a2) are used in the absence of a solvent. Can be used to prepare a urethane prepolymer having a hydroxyl group, and then, the (meth)acrylic compound (a3) having an isocyanate group is supplied, mixed and reacted to produce a urethane prepolymer. .. The reaction is preferably carried out, for example, under conditions of 20 to 120° C. for 30 minutes to 24 hours.

The urethane resin (a) may be produced in the presence of an organic solvent.

Examples of the organic solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate, ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone and cyclohexanone, ether esters such as methyl cellosolve acetate and butyl cellosolve acetate. A solvent, an aromatic hydrocarbon solvent such as toluene and xylene, an amide solvent such as dimethylformamide and dimethylacetamide, and the like can be used alone or in combination of two or more.

The reaction of the polyol (a1), the polyisocyanate (a2), and the (meth)acrylic compound (a3) at the time of producing the urethane resin (a) is caused by the hydroxyl group contained in the polyol (a1) and the ( Equivalent ratio of the total amount of the hydroxyl groups of the (meth)acrylic compound (a3) to the total amount of the isocyanate groups of the polyisocyanate (a2) and the isocyanate groups of the (meth)acrylic compound (a3) [isosiato group/hydroxyl group ]=0.75-1 is preferable in order to control the molecular weight of the urethane resin (a) to be obtained, and more preferably 0.79-0.995. The reaction may be carried out when the equivalent ratio exceeds 1, but in that case 1,2-propylene glycol or 1,3-propylene glycol is used for the purpose of deactivating the isocyanate group of the urethane resin (a). It is preferable to use a bifunctional alcohol having primary and secondary hydroxyl groups such as butylene glycol. In that case, 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, and the equivalent ratio of the polyisocyanate group [isocyanate group/hydroxyl group The total amount] is preferably adjusted so as to be within the above range.

As the alcohol that can be used for the purpose of deactivating the isocyanate group of the urethane resin (a), a monofunctional alcohol such as methanol, ethanol, propanol or butanol may be used in combination.

When producing the urethane resin (a), a polymerization inhibitor, a urethanization catalyst and the like may be used if necessary.

Examples of the polymerization inhibitor include 3,5-bister butyl-4-hydroxytoluene, hydroquinone, methyl hydroquinone, hydroquinone monomethyl ether (methoquinone), paratertiary butyl catechol methoxyphenol, 2,6-ditertiary butyl cresol. , Phenothiazine, tetramethylthiuram disulfide, diphenylamine, dinitrobenzene and the like can be used. These polymerization inhibitors may be used alone or in combination of two or more kinds.

Examples of the urethanization catalyst include nitrogen-containing compounds such as triethylamine, triethylenediamine and N-methylmorpholine; metal salts such as potassium acetate, zinc stearate and tin octylate; dibutyltin laurate and zirconium tetraacetylacetonate. The organic metal compound of and the like can be used. These urethanization catalysts may be used alone or in combination of two or more kinds.

The urethane resin (a) has a (meth)acryloyl group that promotes radical polymerization by light irradiation or heating. The (meth)acryloyl group equivalent of the urethane resin (a) is 1,000 to 200,000 g/eq. because it can further improve the adhesive property and the step followability. Is preferably in the range of 3,000 to 100,000 g/eq. Is more preferable, and the range of 5,000 to 80,000 g/eq. Is more preferable. The (meth)acryloyl group equivalent represents a value obtained by dividing the total mass of the raw materials for the urethane resin (a) by the equivalent weight of the (meth)acrylic group present in the urethane resin (a).

As the mass ratio of the urethane bond in the urethane resin (a), an excellent cohesive force can be imparted, and an adhesive sheet capable of suppressing the formation of bubbles caused by the gas generated from the adherend (b) can be obtained. In addition, in the total amount of the urethane resin (a), it is preferably in the range of 4% by mass to 20% by mass, and more preferably in the range of 5% by mass to 15% by mass. The urethane bond amount of the urethane resin (a) indicates the mass ratio of the urethane bond structure in the raw material to the total mass of the raw material of the urethane resin (a).

Regarding the weight average molecular weight of the urethane resin (a), an excellent cohesive force can be imparted, and in order to obtain an adhesive sheet capable of suppressing the formation of bubbles due to the gas that can be generated from the adherend (b), It is preferably in the range of 5,000 to 200,000, and more preferably in the range of 15,000 to 100,000. The weight average molecular weight of the urethane (meth)acrylate (A) is a value obtained by measurement in the same manner as the number average molecular weight of the polyol (a1).

Moreover, as the said adhesive composition, what contains a well-known polyisocyanate crosslinking agent and a polyfunctional (meth)acrylate compound can be used as needed.

The term "polyfunctional" as used in the present invention means having two or more polymerizable unsaturated double bonds in the molecule.

Examples of the polyisocyanate cross-linking agent include tolylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and other polyisocyanates; trimethylolpropane Additives; these isocyanurate bodies; burette bodies thereof and the like can be used.

Regarding the amount of the polyisocyanate cross-linking agent used, in order to obtain an adhesive sheet that can impart excellent cohesive force and can suppress the formation of bubbles caused by the gas that can be generated from the adherend (b), the urethane is used. It is preferably in the range of 0.1 parts by mass to 10 parts by mass, more preferably in the range of 0.5 parts by mass to 7 parts by mass, relative to 100 parts by mass of the resin (a).

Examples of the polyfunctional (meth)acrylate compound include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tetramethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, hexamethylene glycol. Di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate , Pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, di(trimethylolpropane) di(meth)acrylate, di(trimethylolpropane) tri(meth)acrylate, di (Trimethylolpropane) tetra(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol An aliphatic polyfunctional (meth)acrylate such as hexa(meth)acrylate, a polyfunctional (meth)acrylate having an isocyanurate skeleton such as tris(2-(meth)acryloyloxyethyl)isocyanurate, and the like can be used. These (meth)acrylic compounds may be used alone or in combination of two or more kinds. From the viewpoint that excellent cohesive force can be imparted and foaming caused by the gas generated from the adherend (b) can be suppressed, a polyfunctional compound having an aliphatic polyfunctional (meth)acrylate and/or an isocyanurate skeleton is used. It is preferable to use a functional (meth)acrylate, and one selected from the group consisting of pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and tris(2-(meth)acryloyloxyethyl)isocyanurate. It is more preferable to use the above (meth)acrylic compounds.

Regarding the content of the polyfunctional (meth)acrylate compound, an excellent cohesive force can be imparted, and in order to obtain an adhesive sheet capable of suppressing the formation of bubbles due to the gas that can be generated from the adherend (b). Of 100 parts by mass of the urethane resin (a), preferably 1 part by mass to 30 parts by mass, more preferably 2 parts by mass to 20 parts by mass, and further preferably 3 parts by mass to 10 parts by mass. Ranges are more preferred.

As the adhesive composition, one containing a radical polymerization initiator can be used.

As the radical polymerization initiator, known ones can be used, and examples thereof include a photopolymerization initiator and a peroxide, and the photopolymerization initiator is preferable for maintaining good productivity and the like.

As the photopolymerization initiator, for example, a conventionally known one such as an alkylphenone photopolymerization initiator such as benzophenone, a camphorquinone photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, or a titanocene photopolymerization initiator can be used. ..

Examples of commercially available photopolymerization initiators include benzophenone, 4,4-bis(diethylamino)benzophenone, 2,4,6-trimethylbenzophenone, methylorthobenzoylbenzoate, 4-phenylbenzophenone, t-butylanthraquinone, and 2. Thioxanthones such as ethylanthraquinone, 2,4-diethylthioxanthone, isopropylthioxanthone, and 2,4-dichlorothioxanthone; diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one (for example, BASF Darocur 1173 manufactured by KK, benzyl dimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone (for example, Irgacure 184 manufactured by BASF), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-. Methyl-1-propan-1-one (for example, Irgacure 2959 manufactured by BASF), 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one (for example, Irgacure 907 manufactured by BASF), Acetophenones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone; Benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; 2,4,6 -Acylphosphine oxides such as trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; Methyl benzoyl formate (for example, Vicure 55 manufactured by Stoufer), 1,7-bisacridinyl heptane, 9-phenylacridine, Quantacure (manufactured by International Bio-Synthetics), Kaiacure MBP (Nippon Kayaku) Co., Ltd.), Esacure BO (Fratelli Lamberti), Trigonal 14 (Akzo), Irgacure (BASF), Darocur (Made by company), Speed Cure (Made by company), Darocur 1173 and Fi-4. And the like (manufactured by Eastman) and the like can be used alone or in combination of two or more kinds.

As the photopolymerization initiator, it is preferable to use Irgacure 184, Irgacure 651 or the like, which can be rapidly cured by irradiation with an active energy ray such as ultraviolet rays.

Examples of the peroxide usable as the radical polymerization initiator include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxydicarbonate, cumene hydroperoxide, and peroxy. Conventionally known peroxides such as esters can be used. These may be used alone or in combination of two or more. Among these, peroxyester and peroxydicarbonate are preferable, and peroxydicarbonate is particularly preferable for curing under high temperature conditions of 80 to 120°C. Examples of the peroxydicarbonate include di(4-t-butylcyclohexyl)peroxydicarbonate, and commercially available products include Perloyl TCP (manufactured by NOF Corporation). Among them, as the peroxide, it is preferable to use perloyl TCP which can be rapidly cured by irradiation with active energy rays such as ultraviolet rays.

The radical polymerization initiator is preferably used in the range of 0.01 parts by mass to 10 parts by mass, and is used in the range of 0.05 parts by mass to 5 parts by mass with respect to 100 parts by mass of the urethane resin (a). More preferably.

The adhesive composition of the present invention may contain other additives as necessary.

Examples of the other additives include silane coupling agents, antioxidants, light stabilizers, rust inhibitors, thixotropic agents, sensitizers, polymerization inhibitors, leveling agents, tackifiers, antistatic agents. , Flame retardants and the like can be used. These additives may be used alone or in combination of two or more kinds. Among these, when the adhesive sheet of the present invention is used for applications requiring high adhesive physical properties after heat and humidity resistance, it is preferable to contain a silane coupling agent. Further, when the adhesive sheet of the present invention is used in applications requiring high resistance to yellowing due to heat and moisture, it is preferable to contain an antioxidant and a light stabilizer.

Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane. A silane coupling agent having an epoxy group such as; 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl) ) Ethylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)propyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)propylmethyldimethoxy Silane, a silane coupling agent having an alicyclic epoxy group such as 2-(3,4-epoxycyclohexyl)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)propylmethyldiethoxysilane; vinyltrichlorosilane, vinyl Trimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltri Ethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, silicone alkoxy oligomer and the like can be used. These silane coupling agents may be used alone or in combination of two or more kinds. Among these, it is preferable to use a silane coupling agent having an epoxy group and/or a silane coupling agent having an alicyclic epoxy group, from the viewpoint that the adhesive strength after heat and humidity resistance can be further improved. 4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. More preferably, one or more silane coupling agents are used.

As the antioxidant, a hindered phenol compound (primary antioxidant) that captures radicals generated by heat deterioration, and a phosphorus compound or sulfur compound (secondary oxidation prevention that decomposes peroxide generated by heat deterioration) are used. Agents) and the like can be used.

Examples of the hindered phenol compound include triethylene glycol-bis-[3-(3-t-butyl-5-methyl-4hydroxyphenyl)propionate] and pentaerythritol tetrakis[3-(3,5-di-). tert-Butyl-4-hydroxyphenyl)propionate, octadecyl[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, thiodiethylenebis[3-(3,5-di-tert-butyl- 4-hydroxyphenyl) propionate], benzenepropanoic acid 3,5-bis (1,1-dimethylethyl) -4-hydroxy -C ₇ -C ₉ side chain alkyl ester, 4,6-bis (dodecylthiomethyl) -O-cresol, a reaction product of N-phenylbenzenamine and 2,4,4-trimethylpentene, 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)- 4-methylphenyl acrylate, 3,9-bis[2-[3-(t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]2,4,8,10- Tetraoxaspiro[5.5]undecane, 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,5-di-tert. -Amyl hydroquinone or the like can be used. These compounds may be used alone or in combination of two or more.

Examples of the phosphorus compound include triphenylphosphine, bis(2,4-di-tert-butyl-6-methylphenyl)=ethyl=phosphite, triphenylphosphite, trisnonylphenylphosphite, tris(2, 4-dibutylphenyl)phosphite, tris(2,4-dibutyl-5-methylphenyl)phosphite, tris[2-tert-butyl-4-(3-butyl-4-hydroxy-5-methylphenylthio)- 5-methylphenyl]phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tridecylphosphite, octyldiphenylphosphite, di(decyl)monophenylphosphite, di(tridecyl)pentaerythritoldi Phosphite, di(nonylphenyl)pentaerythritol diphosphite, bis(2,4-dibutylphenyl)pentaerythritol diphosphite, bis(2,6-dibutyl-4-methylphenyl)pentaerythritol diphosphite, bis( 2,4,6-tributylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tetra(tridecyl)isopropylidene diphenol diphosphite, tetra(tridecyl)-4, 4'-n-butylidene bis(2-butyl-5-methylphenol) diphosphite, hexa(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-butylphenyl)butane triphosphite, tetrakis( 2,4-dibutylphenyl)biphenylene diphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis(4,6-butylphenyl)-2 -Ethylhexyl phosphite, 2,2'-methylenebis(4,6-butylphenyl)-octadecyl phosphite, 2,2'-ethylidene bis(4,6-dibutylphenyl)fluorophosphite, tris(2-[(2 , 4,8,10-Tetrakisbutyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy]ethyl)amine, 2-ethyl-2-butylpropylene glycol and 2, Phosphite of 4,6-tributylphenol and the like can be used. These compounds may be used alone or in combination of two or more.

Examples of the sulfur compound include didodecyl-3,3'-thiopropionate, dilauryl-3,3'-thiodipropionate, laurylylthiodithionate, ditridecyl-3,3'-thiodipropionate, Dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, tetrakis-methylene-3-laurylthiopropionate methane, distearyl-3,3'-methyl-3, 3'-thiodipropionate, lauryl stearyl-3,3'-thiodipropionate, bis[2-methyl-4-(3-n-alkylthiopropionyloxy)-5-t-butylphenyl] sulfide, β- Lauryl thiopropionate, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, dioctadecyl-3,3'-thiodiprothionate and the like can be used. These compounds may be used alone or in combination of two or more.

Among these, it is preferable to use a phosphorus compound in order to further improve the adhesive strength and wet heat yellowing, and triphenylphosphine, bis(2,4-di-tert-butyl-6-methylphenyl)=ethyl. = It is more preferable to use one or more antioxidants selected from the group consisting of phosphite and tris(2,4-di-tert-butylphenyl)phosphite, and triphenylphosphine and bis(2,4-diphenyl) It is more preferred to use -tert-butyl-6-methylphenyl)=ethyl=phosphite.

The amount of the antioxidant used is 0.01 part by mass to 10 parts by mass with respect to 100 parts by mass of the urethane resin (a), because the moisture-heat yellowing resistance can be further improved. It is preferable to have.

The light stabilizer captures radicals generated by photodegradation, and for example, a radical scavenger such as a thiol compound, a thioether compound, a hindered amine compound; an ultraviolet absorber such as a benzophenone compound or a benzoate compound may be used. it can. These light stabilizers may be used alone or in combination of two or more kinds. Among these, it is preferable to use the hindered amine compound from the viewpoint of further improving the wet heat yellowing resistance.

Examples of the hindered amine compound include a reaction product of cyclohexane and N-butyl peroxide 2,2,6,6-tetramethyl-4-piperidineamine-2,4,6-trichloro-1,3,5-triazine. And 2-aminoethanol reaction product, decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester, 1,1-dimethylethyl hydroperoxide and octane A hindered amine compound having an amino ether group such as a reaction product of N; acetyl N-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl)pyrrolidine-2,5-dione -Acetyl-based hindered amine compound; bis(1,2,2,6,6-pentamethyl-4-piperidyl)=decanedioate, bis(1,2,2,6,6-pentamethyl-4-piperidyl){[ 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl}butyl malonate, dimethyl succinate. 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6- Use of tetramethylpiperidine polycondensate, N-alkyl hindered amine compound of provandioic acid [{4-methoxyphenyl}methylene]-bis(1,2,2,6,6-pentamethyl-4-piperidyl) ester, etc. You can These compounds may be used alone or in combination of two or more.

The amount of the light stabilizer used is in the range of 0.01 parts by mass to 10 parts by mass based on 100 parts by mass of the urethane resin (a) from the viewpoint that the moisture-heat yellowing resistance can be further improved. It is preferable to have.

[Adhesive sheet]
The adhesive sheet of the present invention can be produced, for example, by coating the adhesive composition on one surface of a release film, and drying the adhesive if necessary to form the adhesive layer (A).

Examples of the method of applying the adhesive composition to the surface of the release film include a method of using a comma coater or a lip coater. The drying can be performed using, for example, a dryer set to a temperature of about 60°C to 90°C.

The adhesive layer (A) preferably has a thickness of 25 μm to 300 μm, and more preferably has a thickness of 50 μm to 175 μm. In particular, when the adhesive sheet comprising a single layer of the adhesive layer (A) is used, it is preferable to use an adhesive sheet having a thickness within the above range. The adhesive sheet having a thickness in the above range can maintain a level of transparency that can be used for optical applications, can follow the irregularities of the adherend (b), and can improve the adhesion. As a result, it is possible to suppress the formation of bubbles caused by the gas that can be generated from the adherend (b).

The adhesive sheet of the present invention obtained by the above method preferably has a thickness of 50 μm to 300 μm, and more preferably has a thickness of 100 μm to 250 μm. The adhesive sheet having a thickness in the above range can maintain a level of transparency that can be used for optical applications, can follow the irregularities of the adherend (b), and can improve the adhesion. As a result, it is possible to suppress the formation of bubbles caused by the gas that can be generated from the adherend (b). The above thickness refers to the thickness not including the release film.

Further, the adhesive sheet of the present invention can exhibit the above-mentioned effects even if it is thin as described above, and can maintain the surface hardness derived from the adherend, so that it is required to be thin, for example. It can be suitably used when manufacturing an information display device and the like.

As the adhesive sheet of the present invention, when used for manufacturing the information display device or the like, it is preferable to use an adhesive sheet having a transmittance of light having a wavelength of 380 nm to 780 nm of 85% or more and a haze of 2.0 or less. It is preferable to use a display having a transmittance of light having a wavelength of 380 nm to 780 nm of 90% or more and a haze of 1.5 or less in order to maintain the transparency of the image display portion of the display.

When the adhesive sheet of the present invention is used for manufacturing the information display device, etc., it is exposed to light having a wavelength of 380 nm to 780 nm after being left in an environment of a temperature of 85° C. and a relative humidity of 85% RH for 500 hours. Having a transmittance of 85% or more and a haze of 2.0 or less is preferably used, and a material having a transmittance of 90% or more and a haze of 1.5 or less for light having a wavelength of 380 nm to 780 nm is used. It is preferable to maintain good transparency of the image display part such as a display.

The adhesive sheet of the present invention can be suitably used for bonding two or more adherends (B). Among them, the adhesive sheet of the present invention can be suitably used for adhering an adherend (b) that can generate gas when left for 24 hours in an environment of a temperature of 60° C. and a humidity of 90%.
The adhesive sheet of the present invention can be suitably used for laminating two or more adherends (b) or laminating the adherend (b) with another adherend.

Examples of the adherend (b) include a transparent member made of plastic.

Examples of the transparent member constituting the adherend (b) include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, cellophane, diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, polyvinyl chloride, Resin base materials such as polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polystyrene, polycarbonate, polymethylpentene, polysulfone, polyetheretherketone, polyethersulfone, polyetherimide, polyimide, nylon, acrylic resin, etc. Can be used. Among them, as the resin base material, polycarbonate and acrylic resin are preferable in terms of achieving both high transparency and surface hardness. However, a resin base material such as polycarbonate easily generates gas at about 80° C., which forms bubbles and causes peeling or the like. If the adhesive sheet of the present invention, even when using a polycarbonate or the like, because it is difficult to form bubbles due to gas, does not cause peeling, and also retains excellent transparency and hardness due to the polycarbonate and the like. it can.

Specific examples of the adherend (b) include an image display panel having a decorative layer for the purpose of imparting a design property, a light-shielding property, and the like.

As the adherend (b), it is preferable to use one having a thickness of 0.3 mm to 5 mm, more preferably one having a thickness of 0.7 mm to 4 mm, and more preferably 1 mm to 3 mm. It is preferable to use one having a size as described above, because rigidity can be imparted to protect articles such as an information display device.

An image display device, a touch panel device, or the like can be used as another adherend to be attached to the adherend (b).
As the adherend (B), one having a decorative layer (step portion) on a part of its surface can be used.
Examples of the decorative layer include layers provided by printing by a general printing method. Examples of the printing method include a silk printing method, a screen printing method, a thermal transfer printing method, and a gravure printing method.

The decorative layer is not particularly limited as long as it imparts various design properties to the transparent member, and for example, characters or figures visually recognized around the image display portion when used as an image display panel, or, Examples thereof include a black frame-shaped decorative layer provided in a frame shape in the image display unit.

The thickness of the decorative layer is preferably in the range of 2 μm to 50 μm, more preferably in the range of 5 μm to 40 μm, and even more preferably in the range of 10 μm to 30 μm. Defects can be suppressed, suitable design characteristics can be easily imparted, and products such as the information display device can be made thin.

As a method for manufacturing an article by adhering two or more adherends (B) including the adherend (b) with the adhesive sheet, for example, the two or more adherends (B) at a temperature of 100° C. and Laminating via an active energy ray-curable polyurethane adhesive sheet having an adhesive layer (A) having a storage elastic modulus (G′ _A100 ) of less than 1×10 ⁵ Pa measured at a frequency of 1 Hz, and the activity. A cured layer (A′) having a storage elastic modulus (G′ _A′100 ) of 2×10 ⁵ Pa or more measured at a temperature of 100° C. and a frequency of 1 Hz by irradiating an energy ray-curable polyurethane adhesive sheet with an active energy ray. ) Is included. At that time, when a part of the adherend is transparent, active energy rays can be irradiated from the surface of the adherend.

The active energy ray is used to cure the adhesive layer (A) forming the adhesive sheet to form a cured layer (A′).

Ultraviolet rays are preferably used as the active energy rays. The ultraviolet rays may be irradiated in an atmosphere of an inert gas such as nitrogen gas or in an air atmosphere in order to efficiently carry out the curing reaction by the ultraviolet rays. Further, if necessary, heat may be used together as an energy source, and irradiation with an active energy ray may be followed by heating.

When ultraviolet rays are used as active energy rays, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, electrodeless lamps (fusion lamps), chemical lamps, black light lamps, mercury-xenon lamps, short arc lamps , Helium/cadmium laser, argon laser, sunlight, LED and the like. Further, a xenon-flash lamp capable of flashing active energy rays is preferable because the influence of heat on the substrate can be minimized.

As the above-mentioned active energy ray irradiation device, in addition to the above-mentioned ones, a germicidal lamp, carbon arc, xenon lamp, metal halide lamp, scanning type, curtain type electron beam accelerator, etc. can be used.

The article bonded by the bonding method has a structure in which two or more adherends (B) including the adherend (b) are laminated via a cured product of the active energy ray-curable polyurethane adhesive sheet. Have.
The information display device such as a liquid crystal display (LCD), an organic EL display, etc. as the above-mentioned article is, for example, information mounted on an electronic notebook, a mobile phone, a smartphone, a mobile audio player, a PDA, a mobile electronic terminal such as a tablet terminal, A display device may be used.

<Synthesis of Urethane Resin (a1) Composition>
In a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, 94.3 parts by mass of polypropylene glycol (number average molecular weight; 1,000), 0.3 parts by mass of 2-hydroxyethyl acrylate, 1,4-hexane. 19.5 parts by mass of dimethanol, 0.5 parts by mass of 2,6-ditertiarybutylcresol, 0.1 parts by mass of p-methoxyphenol, and 57.4 parts by mass of ethyl acetate were added.
After raising the temperature in the reaction vessel to 40° C., 50.3 parts by mass of isophorone diisocyanate was added.
Next, 0.01 part by mass of dioctyltin dineodecat was added, the temperature was raised to 75° C. over 1 hour, and the temperature was held at 75° C. for 12 hours, then, 51.7 parts by mass of ethyl acetate was added, and 30 The urethane resin (a1) composition was obtained by stirring and cooling until uniform for a minute.

<Synthesis of acrylic resin (a2) composition>
In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet, 80 parts by mass of n-butyl acrylate, 15 parts by mass of methyl methacrylate, 4 parts by mass of acrylic acid, and 2,2 as a polymerization initiator. 0.2 parts by mass of'-azobisisobutylnitrile was dissolved in ethyl acetate and polymerized to obtain an acrylic resin (a2) composition.

<Preparation of adhesive composition (b1)>
In a reaction vessel equipped with a stirrer and a thermometer, 10 parts by mass of trimethylolpropane triacrylate ("Aronix M-309" manufactured by Toagosei Co., Ltd.) per 100 parts by mass of the solid content of the urethane resin (a1) composition, 0.3 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone and 0.5 parts by mass of decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester. , 0.5 parts by mass of triphenylphosphine were sequentially added and stirred until uniform.
Next, 1.2 parts by mass of hexamethylene diisocyanate nurate compound (“Bernock D-100S” manufactured by DIC Corporation, hereinafter abbreviated as “100S”) and 0.004 parts by mass of dioctyltin dineodecanate are added. Then, the mixture was stirred until it became uniform, and then filtered through a 200-mesh wire net to obtain an adhesive composition (b1).

<Preparation of adhesive composition (b2)>
In a reaction vessel equipped with a stirrer and a thermometer, 5 parts by mass of trimethylolpropane triacrylate ("Aronix M-309" manufactured by Toagosei Co., Ltd.) per 100 parts by mass of the solid content of the urethane resin (a1) composition, 0.3 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone and 0.5 parts by mass of decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester. , 0.5 parts by mass of triphenylphosphine were sequentially added and stirred until uniform. Further, a nurate compound of hexamethylene diisocyanate (1.2 parts by mass of "Bernock D-100S" manufactured by DIC Corporation) and 0.004 parts by mass of dioctyltindineodecanate were added, and the mixture was stirred until it became uniform. An adhesive composition (b2) was obtained by filtering with a mesh wire mesh.

<Preparation of adhesive composition (b3)>
In a reaction vessel equipped with a stirrer and a thermometer, 0.18 E-5XM (manufactured by Soken Chemical Co., Ltd., solid content: 5% by mass) as an epoxy-based cross-linking agent was added to 100 parts by mass of the solid content of the acrylic resin (a2). 0.2 parts by mass of Coronate L-45 (manufactured by Nippon Polyurethane Industry Co., Ltd., solid content: 45% by mass) as an isocyanate cross-linking agent is added, and the mixture is stirred for 20 minutes with a stirrer to obtain an adhesive composition (b3). ) Got.

(Example 1)
The adhesive composition (b1) was coated on a 100 μm-thick polyester film (hereinafter, “#100 release film”) having a release treatment on one side with a silicone compound so that the thickness after drying was 100 μm. , And dried at 85° C. for 5 minutes, and a 75 μm-thick polyester film (hereinafter, “#75 release film”) was attached to the surface to prepare an active energy ray-curable polyurethane adhesive sheet (c1).

(Example 2)
An adhesive sheet (c2) was obtained in the same manner as in Example 1 except that the adhesive composition (b2) was used instead of the adhesive composition (b1).

(Comparative Example 1)
The adhesive composition (b3) was applied onto a #100 release film so that the thickness after drying was 50 μm, and dried at 85° C. for 4 minutes, and then a #75 release film was attached to the surface thereof. An adhesive sheet (c3) was prepared by aging at 23° C. for 7 days.

(Evaluation method of foaming resistance)
The #75 release film of the adhesive sheets prepared in Examples and Comparative Examples was removed, and a polyethylene terephthalate film having a smooth surface of 5 cm in length, 5 cm in width and 100 μm in thickness was attached.

Next, the #100 release film was removed, and a polycarbonate plate having a length of 5 cm and a width of 5 cm (manufactured by Mitsubishi Gas Chemical Co., Inc., product number Iupilon NF2000, thickness 1.5 mm) was attached to the surface. After leaving it in an environment of 5 atm and 50° C. for 30 minutes, it was irradiated with ultraviolet rays at 1500 mJ/cm ² using an electrodeless lamp (fusion lamp H bulb) to obtain a patch.

After leaving the above-mentioned patch for 500 hours in a 100° C. environment, the appearance of the patch was evaluated according to the following criteria.

<Evaluation of the presence of bubbles>
⊚: There were no fine bubbles.
◯: There were very few fine bubbles, but there was no problem in practical use.
X: There were slight air bubbles.

(Adhesive strength evaluation method)
The #75 release film of the adhesive sheets prepared in Examples and Comparative Examples was removed, and the film was attached to a polyethylene terephthalate film having a thickness of 25 μm and cut into a size of width 25 mm and length 100 mm to obtain a test piece.

Next, the #100 release film of the test piece was removed, and a polycarbonate plate having a width of 50 mm and a length of 150 mm (manufactured by Mitsubishi Gas Chemical Co., Inc., product number Iupilon NF2000, thickness 1.5 mm) was attached to the surface thereof. After leaving it for 30 minutes in an atmosphere of atmospheric pressure and 50° C., it was irradiated with ultraviolet rays of 1500 mJ/cm ² using an electrodeless lamp (fusion lamp H bulb) to obtain a patch.

After the above-mentioned patch was allowed to stand in an environment of a temperature of 23° C. and a relative humidity of 50% RH for 1 hour, the 180° peeling adhesive strength at a peeling speed of 300 mm/min was measured.

(Evaluation method of total light transmittance and haze)
The adhesive sheet from which the release film had been removed was attached to glass, and then left in an environment of 85° C. and 85% RH for 500 hours to obtain an attached product. The total light transmittance and haze of the patch were measured using "HR-100 type" manufactured by Murakami Color Research Laboratory Co., Ltd.

The adhesive sheets of Examples 1 and 2 had good foaming resistance and excellent transparency. On the other hand, the adhesive sheet of Comparative Example 1 had bubbles or became cloudy after being left under high temperature and high humidity conditions.

Claims (7)

An active energy ray-curable polyurethane adhesive sheet having an adhesive layer (A) having a storage elastic modulus (G′ _A100 ) of less than 1×10 ⁵ Pa measured at a temperature of 100° C. and a frequency of 1 Hz,
The adhesive layer (A) contains a polyurethane resin having a hydroxyl group and a (meth)acryloyl group obtained by reacting a polyol and a polyisocyanate, a polyfunctional (meth) acrylate, and an adhesive containing a polyisocyanate crosslinking agent. Formed by the composition,
The content of the polyfunctional (meth)acrylate is 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the polyurethane resin,
The content of the polyisocyanate crosslinking agent is 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of the polyurethane resin,
The storage elastic modulus (G′ _A′100 ) of the layer (A′) obtained by curing the adhesive layer (A) at a temperature of 100° C. and a frequency of 1 Hz is 2×10 ⁵ Pa or more,
An active energy ray-curable polyurethane adhesive characterized by being used for adhesion of an adherend (b) containing a polycarbonate capable of generating a gas when left in an environment of a temperature of 60° C. and a humidity of 90% for 24 hours. Sheet. The active energy ray-curable polyurethane adhesive sheet according to claim 1, wherein the adhesive layer (A) has a thickness in the range of 50 µm to 300 µm. The active energy ray-curable polyurethane adhesive sheet according to claim 1 or 2, wherein the 180° peeling adhesive strength of the cured layer (A′) to the polycarbonate substrate is in the range of 5 N/25 mm to 50 N/25 mm. Two or more adherends (B) including the adherend (b) are laminated via the cured product of the active energy ray-curable polyurethane adhesive sheet according to any one of claims 1 to 3. An article having a composition. Two or more adherends (B) including the adherend (b) are laminated via the cured product of the active energy ray-curable polyurethane adhesive sheet according to any one of claims 1 to 3. An information display device having a configuration. Two or more adherends (B) including the adherend (b) have a storage elastic modulus (G′ _A100 ) of less than 1×10 ⁵ Pa measured at a temperature of 100° C. and a frequency of 1 Hz, a polyol, and Polyurethane resin having a hydroxyl group and a (meth)acryloyl group obtained by reacting polyisocyanate, 1 to 30 parts by mass of polyfunctional (meth) acrylate with respect to 100 parts by mass of the polyurethane resin , and the polyurethane resin 100. Laminating via an active energy ray-curable polyurethane adhesive sheet having an adhesive layer (A) formed by an adhesive composition containing 0.1 part by mass to 10 parts by mass of a polyisocyanate crosslinking agent with respect to parts by mass. And the storage elastic modulus (G′ _A′100 ) measured at a temperature of 100° C. and a frequency of 1 Hz by irradiating the active energy ray-curable polyurethane adhesive sheet with an active energy ray is 2×10 ⁵ Pa or more. The method for producing an article, comprising the step of forming a cured layer (A′) that is The method for producing an article according to claim 6, wherein the adherend (b) contains a polycarbonate capable of generating a gas when left in an environment of a temperature of 60° C. and a humidity of 90% for 24 hours.