TWI636110B - UV-curable adhesive composition and adhesive - Google Patents

Abstract

The problem to be solved by the present invention is to provide an ultraviolet curable adhesive composition having excellent adhesion, moist heat whitening resistance, and moist heat yellowing resistance. The present invention provides a UV-curable adhesive composition, which is characterized by containing: a urethane (meth) acrylate (X), which is a polyol (a) containing a polyethylene glycol (a1), a polymer An isocyanate (b) and a (meth) acrylic compound (c) having a hydroxyl group or an isocyanate group are obtained by reaction; a (meth) acrylic monomer (Y); and a photopolymerization initiator (Z); and An adhesive obtained by using this composition. The adhesive obtained by using the ultraviolet-curable adhesive composition of the present invention can be ideally used as an adhesive for optical members. In particular, it can be ideally used in the manufacture of IT-related products such as touch panels, liquid crystal displays, plasma displays, organic ELs, personal computers, and mobile phones.

Description

UV-curable adhesive composition and adhesive

The present invention relates to an ultraviolet-curable adhesive composition and an adhesive with excellent adhesion, moist heat whitening resistance, and moist heat yellowing resistance.

Acrylic adhesives have been widely used in the past. Especially in recent years, the use of IT-related products such as thin TVs has expanded, and high performance and high performance have been made. However, the prices of IT-related products have also fallen, demanding not only high performance but also high productivity.

In this situation, UV-curable adhesives are valued. Because conventional adhesives (solvent-based, water-based) do not require solvent drying steps, or they must wait for curing time after processing until performance is displayed. We can expect high productivity. In addition, because it is easier to thicken the adhesive layer than conventional adhesives, there are many benefits such as high performance that can be expected, and future development is expected.

The UV-curable adhesives that can be used for the aforementioned IT-related products include, for example, the following adhesive compositions: 100 parts by mass of the monomer with unsaturated double bonds, containing 5 parts by mass or more and 200 parts by mass or less. A high molecular weight body having a urethane bond and having an unsaturated double bond at the polymer terminal with a weight average molecular weight of 20,000 or more (for example, refer to Patent Document 1).

However, the aforementioned adhesives have the following problems: after using the adhesives under humid and hot conditions, if they are left at room temperature, whitening of the adhesive coating film occurs, or yellowing occurs over time. [Prior Art Literature] [Patent Literature]

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

(Problems to be Solved by the Invention)

The problem to be solved by the present invention is to provide an ultraviolet curable adhesive composition having excellent adhesion, moist heat whitening resistance, and moist heat yellowing resistance. (The way to solve the problem)

The inventors of the present invention have made intensive studies in order to solve the aforementioned problems, and focused on urethane (meth) acrylate.

As a result, it has been found that the above-mentioned problem can be solved by including a polyethylene glycol as an essential component of a polyol as a raw material of the urethane (meth) acrylate, and the present invention has been completed.

That is, the present invention provides a UV-curable adhesive composition, which is characterized by containing: a urethane (meth) acrylate (X), which is composed of a polyol (a) containing polyethylene glycol (a1) , Polyisocyanate (b), and (meth) acrylic compound (c) having a hydroxyl group or an isocyanate group, obtained by reaction; (meth) acrylic monomer (Y); and a photopolymerization initiator (Z). The adhesive obtained by using this composition is also provided. (Effect of the invention)

The adhesive obtained by using the ultraviolet-curable adhesive composition of the present invention has excellent adhesion, retention, moist heat whitening resistance, and moist heat yellowing resistance.

The adhesive obtained by using the ultraviolet-curable adhesive composition of the present invention can be suitably used as an adhesive for optical members. In particular, it is suitable for manufacturing IT-related products such as touch panels, liquid crystal displays, plasma displays, organic ELs, personal computers, and mobile phones.

The ultraviolet-curable adhesive composition of the present invention contains: a urethane (meth) acrylate (X), which is a polyol (a) and a polyisocyanate (b) containing polyethylene glycol (a1) And (meth) acrylic compound (c) having a hydroxyl group or an isocyanate group; and (meth) acrylic monomer (Y); and a photopolymerization initiator (Z).

The polyethylene glycol (a1) improves the hydrophilicity of the UV-curable adhesive composition, and can uniformly absorb moisture or moisture when the adhesive coating film is exposed to hot and humid conditions, so it helps Adhesive coating is resistant to whitening after damp and heat. In addition, by using the aforementioned polyethylene glycol (a1), the amount of (meth) acrylic monomer that is easily yellowed can be reduced or not used, so it can maintain the adhesion and provide excellent heat and humidity resistance. transsexual.

The aforementioned polyethylene glycol (a1) is used as a raw material of the urethane (meth) acrylate (X), but in consideration of adhesion, moist heat whitening resistance, and moist heat yellowing resistance, a linear or branched one can be used. The urethane (meth) acrylate (X) may exist as a graft chain or a block chain.

The number-average molecular weight of the aforementioned polyethylene glycol (a1) is preferably in the range of 200 to 5,000 from the viewpoint of further improving moist heat whitening resistance and moist heat yellowing resistance, and considering the ease of control of reactivity during synthesis or From the viewpoint of better storage stability at low temperature, a range of 200 to 2,000 is more preferable, and a range of 200 to 1,000 is more desirable. The number-average molecular weight of the polyethylene glycol (a1) refers to 値 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 are connected in series. `` TSKgel G5000 '' (7.8mmI.D. × 30cm) × 1 piece “TSKgel G4000” (7.8mmI.D. × 30cm) × 1 piece "G2000" (7.8mmI.D. x 30cm) x 1 detector: RI (differential refractometer) column temperature: 40 ° C eluent: tetrahydrofuran (THF) flow rate: 1.0mL / min injection volume: 100μL (sample Tetrahydrofuran solution with a concentration of 0.4% by mass) Standard sample: A calibration curve was prepared using the following standard polystyrene.

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

From the viewpoint of further improving the adhesion, retention, moist heat whitening resistance and moist heat yellowing resistance, the amount of the polyethylene glycol (a1) used should be in the range of 1 to 60% by mass of the polyol (a). It is better, the range of 3 to 50% by mass is better, the range of 5 to 40% by mass is even better, and the range of 10.5 to 33% by mass is even better.

In addition, from the viewpoint of further improving the adhesion, retention, moist heat whitening resistance, and moist heat yellowing resistance, the content of the polyethylene glycol (a1) in the urethane (meth) acrylate (X) is preferably A range of 0.1 to 50% by mass is preferable, a range of 5 to 35% by mass is more preferable, and a range of 9 to 25% by mass is more desirable.

The polyol (a) that can be used other than the polyethylene glycol (a1), for example, polyether polyols other than polyethylene glycol, polyester polyols, polycarbonate polyols, acrylic polyols, butadiene Olefin polyols and the like. These polyols may be used alone or in combination of two or more. Among these, it is preferable to use the aforementioned polyether polyols and polycarbonate polyols from the viewpoints of further improving adhesion, retention, moist heat whitening resistance, and moist heat yellowing resistance.

The aforementioned polyether polyol is obtained by addition polymerization of one or more alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to a compound having two or more active hydrogens. Product, or polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran, modified polytetramethylene glycol obtained by copolymerization of tetrahydrofuran and alkyl-substituted tetrahydrofuran, or modified copolymer of neopentyl glycol and tetrahydrofuran. Polytetramethylene glycol and so on.

As the compound having two or more active hydrogens, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, and tripropylene glycol can be used. , 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1 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-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2 -Methyl-1,8-octanediol, hydroquinone, resorcinol, bisphenol A, bisphenol F, 4,4'-bisphenol and other lower molecular weight dihydroxy compounds; 1,2-cyclobutane Diols, 1,3-cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, 1,4-cyclohexanedimethanol, hydroxypropylcyclohexanol, tricyclic [5,2,1,0,2,6] decane-dimethanol, bicyclic [4,3,0] -nonanediol, dicyclohexanediol, tricyclic [5,3,1,1] Dioxanediol, bicyclo [4,3,0] nonanedimethanol Tricyclo [5,3,1,1] dodecane-diethanol, hydroxypropyltricyclo [5,3,1,1] dodecanol, spiro [3,4] octanediol, butylcyclohexyl Alicyclic polyols such as diols, 1,1'-bicyclohexylene glycol, cyclohexanetriol, hydrogenated bisphenol A, 1,3-adamantanediol; polyethylene glycol, polypropylene glycol, polytetramethylene Polyether polyols such as methyl glycol; polyester polyols such as polyhexamethylene adipate, polyhexamethylene succinate, and polycaprolactone.

The number average molecular weight of the aforementioned polyether polyol is preferably in the range of 200 to 3,000, more preferably in the range of 500 to 2,000, and more preferably in the range of 500 to 1,500. The number-average molecular weight of the polyether polyol represents the same as that obtained by measuring the number-average molecular weight of the polyethylene glycol (a1).

The polycarbonate polyol may be obtained by, for example, reacting a carbonate and / or phosgene with the compound having two or more active hydrogens.

Examples of the carbonate include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclic carbonate, and diphenyl carbonate.

The hydroxyl value of the aforementioned polycarbonate polyol is preferably in the range of 30 to 230 mgKOH / g, and more preferably in the range of 50 to 230 mgKOH / g. In addition, the hydroxyl value of the said polycarbonate polyol represents 値 measured according to JISK0070-1992.

As the polyisocyanate (b), for example, aromatic diisocyanates such as xylene diisocyanate, phenylene diisocyanate, methylenephenyl diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate can be used; hexamethylene Diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, diisocyanoxymethylcyclohexane, tetramethyldioxane Diisocyanates and the like having an aliphatic or alicyclic structure, such as toluene diisocyanate. These polyisocyanates may be used alone or in combination of two or more. Among these, from the viewpoint of further improving the adhesion, holding power, and resistance to heat and yellowing, it is preferable to use a diisocyanate having an alicyclic structure, and 4,4'-dicyclohexylmethane diisocyanate, isophorone Diisocyanate, cyclohexane diisocyanate, and diisocyanatomethylcyclohexane are more preferred.

The (meth) acrylic compound (c) having a hydroxyl group or an isocyanate group is used to introduce a (meth) acrylfluorenyl group into a urethane (meth) acrylate (X).

The aforementioned (meth) acrylic compound having a hydroxyl group that can be used as the aforementioned compound (c), for example: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl acrylate Esters, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl acrylate, hydroxyethylacrylamide and other alkyl (meth) acrylates having hydroxyl groups; three Multifunctional (meth) acrylates with hydroxyl groups such as methylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate; polyethylene glycol monoacrylate , Polypropylene glycol monoacrylate, etc. Among these, it is preferable to use an acrylic compound having a hydroxyl group from the viewpoint of further improving the curing property by using ultraviolet rays, and it is preferable to use a hydroxyl group from the viewpoint of improving raw material easiness, hardening property, and adhesive properties. Alkyl acrylate is more preferred, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are particularly preferred.

As the (meth) acrylic compound having an isocyanate group, which can be used as the compound (c), for example, 2- (meth) acryloxyethyl isocyanate, 2- (2- (methyl) Acrylic ethoxyethoxy) ethyl isocyanate, 1,1-bis ((meth) acrylic ethoxymethyl) ethyl isocyanate, and the like. Among these, from the viewpoint of easiness of obtaining raw materials, it is preferable to use 2- (meth) acryloxyethyl isocyanate, and 2-acryloxyethyl isocyanate is more preferable.

When a (meth) acrylic compound having a hydroxyl group is used as the compound (c), the method for producing the urethane (meth) acrylate (X) may be the following method, for example: After the polyol (a) and the (meth) acrylic compound (c) are added to the reaction system, the polyisocyanate (b) is supplied, mixed, and reacted to produce the method, or the polybasic is made without a solvent The alcohol (a) is reacted with the polyisocyanate (b) to obtain an urethane prepolymer having an isocyanate group. Next, the (meth) acrylic compound (c) having a hydroxyl group is supplied, mixed, and reacted. By manufacturing methods, etc. In the foregoing reactions, the reaction is preferably performed at 20 to 120 ° C. for about 30 minutes to 24 hours.

When a (meth) acrylic compound having an isocyanate group is used as the compound (c), the following methods can be used for the production method of the urethane (meth) acrylate (X), for example, in the absence of a solvent Adding the aforementioned polyol (a) and the aforementioned polyisocyanate (b) and reacting them to obtain a urethane prepolymer having a hydroxyl group; secondly, supplying the aforementioned (meth) acrylic compound (c) having an isocyanate group, A method of mixing and reacting them for production. The foregoing reactions are preferably carried out at 20 to 120 ° C for about 30 minutes to 24 hours.

The production of the urethane (meth) acrylate (X) may be performed in the presence of an organic solvent or an aqueous medium. Moreover, it can also manufacture in the presence of the (meth) acrylic-type monomer (Y) mentioned later, without using an organic solvent or an aqueous medium.

The reaction between the polyol (a), the polyisocyanate (b), and the (meth) acrylic compound (c), the hydroxyl group possessed by the polyol (a), and the (meth) acrylic compound (c) ) Total amount of hydroxyl groups possessed and equivalent ratio of isocyanate groups possessed by polyisocyanate (b) [Total amount of isocyanate group / hydroxyl group] = 0.75 to 1, the obtained urethane (methyl ) The molecular weight of the acrylate (X) is preferable, and the range of 0.79 to 0.995 is more preferable. In addition, it is possible to react when the aforementioned equivalent ratio exceeds 1, but in this case, in order to deactivate the isocyanate group of the urethane (meth) acrylate (X), it is preferable to use an alcohol such as methanol. In this case, the total amount of the hydroxyl group owned by the aforementioned polyol (a) and the hydroxyl group owned by the aforementioned (meth) acrylic compound (c) and the hydroxyl group owned by the alcohol, and the equivalent ratio of the aforementioned polyisocyanate group [isocyanate group / hydroxyl group] Total measurement], it should be adjusted to be more ideal within the aforementioned range.

Moreover, in order to make the alcohol used for the isocyanate group of the said urethane (meth) acrylate (X), monofunctional alcohols, such as methanol, ethanol, propanol, and butanol, 1, 2-propanediol, or Bifunctional alcohols such as 1,3-butanediol and the like composed of primary and secondary hydroxyl groups.

Moreover, when manufacturing a urethane (meth) acrylate (X), you may use a polymerization inhibitor, a urethane-forming catalyst, etc. as needed.

The aforementioned polymerization inhibitors, for example: 3,5-bis-tertiarybutyl-4-hydroxytoluene, hydroquinone, methylhydroquinone, hydroquinone monomethyl ether (methoquinone), p-tert-butyl catechin Phenol methoxyphenol, 2,6-di-tert-butylcresol, phenothiazone, tetramethylthiuram disulfide, diphenylamine, dinitrobenzene, etc.

For the urethane catalyst, for example, nitrogen-containing compounds such as triethylamine, triethylenediamine, and N-methyl □ line, metal salts such as potassium acetate, zinc stearate, and tin octoate, and dibutyl can be used. Organometallic compounds such as tin laurate, zirconium tetraethylammonium pyruvate and the like.

The urethane (meth) acrylate (X) has a (meth) acrylfluorenyl group which undergoes radical polymerization by light irradiation, heating, or the like. In consideration of the viewpoint of improving the adhesive force and the followability of the height difference, the equivalent of the aforementioned (meth) acrylfluorenyl group should preferably be in the range of 1,000 to 200,000 g / eq., And the range of 5,000 to 100,000 g / eq. . The equivalent of the (meth) acrylfluorenyl group is the total mass of the polyol (a), polyisocyanate (b), and (meth) acrylic compound (d), divided by the urethane ( It is obtained by the equivalent of the (meth) acrylic group present in the meth) acrylate (X). In the present invention, "(meth) acrylic compound" means one or both of a methacrylic compound and an acrylic compound, and "(meth) acrylate" means a methacrylate and acrylic acid. One or both of the esters, "(meth) acrylfluorenyl" refers to one or both of methacrylfluorenyl and acrylfluorenyl, and "(meth) acrylic" refers to methacrylic acid and One or both of acrylic acid, and "(meth) acrylic monomer" means one or both of methacrylic monomer and acrylic monomer.

The weight average molecular weight of the aforementioned urethane (meth) acrylate (X) is preferably in the range of 5,000 to 200,000 from the viewpoint of achieving both excellent adhesion and holding power and providing good coating workability. , The range of 10,000 ~ 100,000 is more ideal. The weight average molecular weight of the urethane (meth) acrylate (X) represents fluorene obtained by measuring the same as the number average molecular weight of the polyethylene glycol (a1).

Examples of the (meth) acrylic monomer (Y) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and the like Butyl (meth) acrylate, second butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, n-amyl (meth) acrylate, (formyl) (Hexyl) hexyl acrylate, 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate , 3-methylbutyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, (formyl) Base) aliphatic (meth) acrylates such as neopentyl acrylate, cetyl (meth) acrylate, isoamyl (meth) acrylate; isoamyl (meth) acrylate, cyclohexyl (meth) acrylate Alicyclic (meth) acrylates such as esters, tetrahydrofuran (meth) acrylate; 3-methoxybutyl (meth) acrylate), 2-methoxyethyl (meth) acrylate, (methyl) ) 3-methoxypropyl acrylate, (meth) propylene Acid 2-methoxybutyl ester, methoxy polyethylene glycol acrylate, ethoxy diethylene glycol (meth) acrylate, carbidine (Meth) acrylates having ether groups such as alcohol (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxy (meth) acrylate (Meth) acrylates with hydroxyl groups such as butyl ester; benzyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy polyethylene glycol acrylate, Aromatic (meth) acrylates such as phenyl (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate; (meth) acrylamide, dimethyl (meth) propylene Fluorenylamine, acrylamidinoline, dimethylaminopropyl (meth) acrylamide, isopropyl (meth) acrylamide, diethyl (meth) acrylamide, hydroxyethyl (methyl (Meth) acrylamide, diacetone (meth) acrylamide, and other (meth) acrylic monomers having a nitrogen atom. These (meth) acrylic monomers may be used alone or in combination of two or more.

In addition, the (meth) acrylic monomer (Y) may be a nitrogen (meth) acrylic monomer having a nitrogen atom in order to provide excellent moisture and whitening resistance. In this case, due to the decrease in humidity and heat yellowing resistance, it is preferable to add a small amount. Compared with the total amount of the (meth) acrylic monomer (Y), it is preferably 40% by mass or less, and more preferably 35% by mass or less. . In the present invention, the hydrophilicity of the adhesive coating film can be improved by using the polyethylene glycol (a1), so that it can exhibit moist heat and whitening resistance with a small amount of addition.

From the viewpoint of adhesion, the use amount of the (meth) acrylic monomer (Y) is preferably in a range of 30 to 200 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate (X). Preferably, a range of 50 to 150 parts by mass is more preferred, and a range of 70 to 130 parts by mass is particularly preferred.

The photopolymerization initiator (Z) is a radical that is generated by light irradiation or heating and causes the urethane (meth) acrylate (X) or the (meth) acrylic monomer (Y) to Starter of free radical polymerization.

The aforementioned photopolymerization initiator (Z) is, for example, 4-phenoxydichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 4- (2-hydroxyethoxy) -phenyl (2 -Hydroxy-2-propyl) ketone, 2-methyl- [4- (methylthio) phenyl] -2- □ olino-1-acetone, 2,2-dimethoxy-2-phenyl Acetophenone compounds such as acetophenone; Benzoin compounds such as benzoin, benzoin methyl ether, benzoin isoethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; diphenylketone, benzene Formamylbenzoic acid, methyl benzamylbenzoate, 4-phenyldiphenylketone, hydroxydiphenylketone, 4-benzylmethyl-4'-methyldiphenylsulfide, 3, Diphenyl ketone compounds such as 3'-dimethyl-4-methoxydiphenyl ketone; thioxanthone, 2-chlorothioxanthone, 2,4-dichlorothioxanthone, 2-methylthioxanthone Ketones, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and other thioxanthone compounds; 4, 4'-dimethylaminothioxanthone (alias = michler's ketone), 4,4'-diethylaminodiphenyl Anthraquinone compounds such as ketones, alpha-fluorenyl oxime esters, benzil, methylbenzophenylate ("Vicure 55"), 2-ethylanthraquinone; 2,4,6 -Trimethylbenzylfluorenyl diphenylphosphine oxide (`` Lucirin TPO ''), bis (2,4,6-trimethylbenzylfluorenyl) -phenylphosphine oxide (`` IRGACURE819 ''), etc. Phosphine compound; 3,3 ', 4,4'-tetrakis (third butylperoxycarbonyl) diphenyl ketone ["BTTB" manufactured by Nippon Oil & Fats Co., Ltd.], acrylated diphenyl ketone, etc.

From the viewpoints of further improving the adhesion, holding power, resistance to heat and yellowing, and hardening, the photopolymerization initiator (Z) is preferably 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-Hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzylidene diphenylphosphine oxide, bis (2,4,6-trimethylbenzylidene) -phenylphosphine oxide good.

The amount of the photopolymerization initiator (Z) used is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the urethane (meth) acrylate (X), and 0.5 to 15 parts by mass The range is more preferable, and the range of 1 to 5 parts by mass is particularly preferable.

The ultraviolet-curable adhesive composition of the present invention includes the urethane (meth) acrylate (X), the (meth) acrylic monomer (Y), and the photopolymerization initiator (Z). As an essential component, other additives may be contained as needed.

As the other additives, for example, a silane coupling agent, an antioxidant, a light stabilizer, a solvent, a rust inhibitor, a thixotropy imparting agent, a sensitizer, a polymerization inhibitor, a leveling agent, an adhesion imparting agent, and an antistatic agent can be used. Agents, flame retardants, etc. Among these, considering the point that the performance of the adhesive after the heat and humidity resistance is further improved, it is preferable to contain a silane coupling agent. From the viewpoint of further improving the resistance to moist heat and yellowing, it is preferable to contain an antioxidant and a light stabilizer.

As the silane coupling agent, for example, for example: 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyl Methyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and other silane coupling agents with epoxy groups; 2- (3,4-epoxycyclohexyl) ethyltrisiloxane Ethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, 2- (3 , 4-epoxycyclohexyl) ethylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) propyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) propane Methylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) propyltriethoxysilane, 2- (3,4-epoxycyclohexyl) propylmethyldiethoxysilane And other silane coupling agents with alicyclic epoxy groups; vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane, 3-methacrylic acid Propylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethyl Silane, 3-methacryloxypropyltriethoxysilane, 3-propenyloxypropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane Silane, silicone alkoxy oligomers, etc. These silane coupling agents may be used alone or in combination of two or more. Among these, from the viewpoint of further improving the adhesion after moist and heat resistance, it is preferable to use a silane coupling agent having an epoxy group and a silane coupling agent having an alicyclic epoxy group. -(3,4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxy One or more of the group consisting of silane and 3-glycidoxypropyltriethoxysilane are more preferable.

The amount of the silane coupling agent used is from 0.01 to 10 parts by mass relative to 100 parts by mass of the aforementioned urethane (meth) acrylate (X), from the viewpoint of further improving the adhesion after moist heat resistance. The range of 0.05 to 5 parts by mass is more preferable, and the range of 0.05 to 1 part by mass is more preferable.

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

The aforementioned hindered phenol compounds, for example: triethylene glycol-bis- [3- (3-third-butyl-5-methyl-4hydroxyphenyl) propionate], [3- (3,5-di -Pentaerythritol tertiary butyl-4-hydroxyphenyl) propionate, octadecyl [3- (3,5-di-tertiary butyl-4-hydroxyphenyl) propionate, thiodiethylene ethylbis [3- (3,5-di-third-butyl-4-hydroxyphenyl) propionate], phenylpropanoic acid-3,5-bis (1,1-dimethylethyl) -4-hydroxyl -C ₇ -C ₉ side alkyl ester, 4,6-bis (dodecylthiomethyl) -o-cresol, reaction product of N-phenylaniline and 2,4,4-trimethylpentene, 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenylacrylate, 3,9-bis [2- [3- ( Tert-butyl-4-hydroxy-5-methylphenyl) propanyloxy] -1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro [5.5] undecane , 2,6-di-third-butyl-4-methylphenol, 2,2'-methylenebis (4-methyl-6-third-butylphenol), 2,5-di-third Amyl hydroquinone and the like.

The aforementioned phosphorus compounds, for example: triphenylphosphine, bis (2,4-di-third-butyl-6-methylphenyl) = ethyl = phosphite, triphenylphosphite, and nonanylphenyl Phosphite, ginseng (2,4-dibutylphenyl) phosphite, ginseng (2,4-dibutyl-5-methylphenyl) phosphite, ginseng [2-thirdbutyl- 4- (3-butyl-4-hydroxy-5-methylphenylthio) -5-methylphenyl] phosphite, ginseng (2,4-di-third-butylphenyl) phosphite Tridecyl phosphite, octyl diphenyl phosphite, bis (decyl) monophenyl phosphite, bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite Ester, 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, tetrakis (tridecyl) isopropylidene diphenol diphosphite, Tetrakis (tridecyl) -4,4'-n-butylenebis (2-butyl-5-methylphenol) diphosphite, ter (tridecyl) -1,1,3-ginseng (2- Methyl-4-hydroxy-5-butylphenyl) butanetriphosphite (2,4-dibutylphenyl) biphenyl diphosphinate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene -10-oxide, 2, 2'-methylenebis (4,6-butylphenyl) -2-ethylhexylphosphite, 2,2'-methylenebis (4,6-butylphenyl) -octadecyl Phosphite, 2,2'-ethylenebis (4,6-dibutylphenyl) fluorophosphite, ginseng (2-[(2,4,8,10-silyldibenzo [ d, f] [1,3,2] dioxaphosphepin-6-yl) oxy] ethyl) amine, 2-ethyl-2-butylpropanediol, and 2,4,6 -Phosphites of tributylphenol, etc.

As the sulfur compound, for example, di (dodecyl) 3,3'-thiopropionate, dilauryl 3,3'-dipropionate, dilauryl thiodithiosulfate, 3,3 can be used. Bis (tridecyl) thiodipropionate, bis (myristoyl) thiodipropionate, bis (stearyl) thiodipropionate,- Methylene-3-laurylthiopropionate methane, 3,3'-methyl-3,3'-thiodipropionate di (stearyl) ester, 3,3'-thiodipropionate lauryl Stearyl ester, bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-third butylphenyl] sulfide, β-laurylthiopropionate, 2-mercapto Benzimidazole, 2-mercapto-5-methylbenzimidazole, 3,3'-thiodipropionate di (octadecyl) ester, and the like.

Among these, from the viewpoint of further improving the adhesive force and resistance to heat and yellowing, it is preferable to use a phosphorus compound, which is selected from the group consisting of triphenylphosphine, bis (2,4-di-third-butyl-6) -Methylphenyl) = ethyl = phosphite and ginseng (2,4-di-tert-butylphenyl) phosphite, more than one kind of antioxidant is more preferable, especially Triphenylphosphine, bis (2,4-di-third-butyl-6-methylphenyl) = ethyl = phosphite was used.

The amount of the antioxidant used is preferably in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate (X) from the viewpoint of 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, and ultraviolet absorption such as a diphenyl ketone compound or a benzoate compound can be used. Agent. Among these, from the viewpoint of 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 peroxide 2,2,6,6-tetramethyl-4-piperidinamine-2,4,6-trichloro1,3,5 can be used. -A reaction product of tris (2), 2-aminoethanol, bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) decanedioic acid, Hindered amine compounds having an amine ether group, such as the reaction product of 1,1-dimethylethyl hydrogen peroxide and octane; N-ethylfluorenyl-3-dodecyl-1- (2,2,6,6 -Tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione and other N-acetamidine-based hindered amine compounds; bis (1,2,2,6,6-pentamethyl-4-piperidine) Pyridyl) = decanedione ester, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) fluorene (3,5-bis (1,1-dimethylethyl ) -4-Hydroxyphenyl] methylfluorenyl butyl malonate, dimethyl succinate, 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperazine Pyridine polycondensate, N-alkyl malonate [｛4-methoxyphenyl｝ methylene] -bis (1,2,2,6,6-pentamethyl-4-piperidinyl) ester Hindered amine compounds and the like.

From the viewpoint of improving the resistance to moisture and yellowing, the use amount of the light stabilizer is preferably in the range of 0.01 to 10 parts by mass relative to 100 parts by mass of the urethane (meth) acrylate (X).

The viscosity of the ultraviolet-curable adhesive composition of the present invention is preferably in the range of 500 to 20,000 mPa · s from the viewpoint of good coatability and good handling of the adhesive solution during coating, and 1,000 The range of ~ 15,000mPa · s is more ideal. The aforementioned viscosity is a value measured by a B-type viscosity meter at 25 ° C.

The ultraviolet-curable adhesive composition of the present invention can be hardened by irradiation with energy rays such as ultraviolet rays.

The method for curing the ultraviolet-curable adhesive composition of the present invention can be performed by using a known ultraviolet light irradiation device such as a xenon lamp, a xenon-mercury lamp, a metal halide lamp, a high-pressure mercury lamp, or a low-pressure mercury lamp to irradiate a predetermined ultraviolet ray. hardening.

Irradiation of the ultraviolet ray is preferably 0.05 ~ 5J / cm ^2, more preferably 0.1 ~ 3J / cm ^2, particularly preferably the range of 0.3 ~ 1.5J / cm ² of. In addition, the amount of ultraviolet irradiation is based on a value measured using a UV checker UVR-N1 (manufactured by GS Yuasa Co., Ltd.) in a wavelength range of 300 to 390 nm as a reference.

As a substrate capable of coating the ultraviolet-curable adhesive composition of the present invention and forming an adhesive layer, a plastic substrate, a flexible printing substrate, a glass substrate, and vapor deposition on these substrates can be used. Base material of ITO, etc.

The plastic substrate may be a substrate made of acrylic resin or the like, or PC (polycarbonate), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), modified PPE ( (Polyphenylene ether), PET (polyethylene terephthalate), COP (cycloolefin polymer), TAC (triethylfluorenyl cellulose) or anti-reflective film, antifouling film, and the transparency of the touch panel Films of conductive films, etc. [Example]

The following examples are used to explain the present invention in more detail.

[Synthesis Example 1] <Synthesis of urethane acrylate (X-1)> To a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, polytetramethylene glycol (quantity average molecular weight; 1,000, hereinafter referred to as "PTMG1000") 410 parts by mass, polyethylene glycol (quantity average molecular weight; 400, hereinafter referred to as "PEG-1") 27.5 parts by mass, 2-hydroxyethyl acrylate (hereinafter referred to as "HEA" 6.1 parts by mass, 2 parts by mass of 2,6-di-tert-butylcresol, and 0.3 parts by mass of p-methoxyphenol. After the temperature in the reaction vessel was raised to 40 ° C, 105 parts by mass of isophorone diisocyanate (hereinafter simply referred to as "IPDI") was added. Then, 0.1 part by mass of dioctyltin dineodecanoate was added, and the temperature was raised to 80 ° C. over 1 hour. Thereafter, it was held at 80 ° C. for 12 hours, and after confirming that all isocyanate groups had disappeared, it was cooled to obtain a urethane acrylate (X-1). The urethane acrylate (X-1) obtained had an equivalent of propylene fluorenyl group of 10,441 (rounded up to a decimal point. The molecular weight of 2-hydroxyethyl acrylate was 116.1. The same applies below), and the weight average molecular weight was 30,000.

[Synthesis Example 2] <Synthesis of urethane acrylate (X-2)> A polycarbonate polyol ("Duranol T-5651") was added to a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer. Asahi Kasei Chemical Co., Ltd., number average molecular weight; 1000) 390 parts by mass, polyethylene glycol (number average molecular weight; 600, hereinafter referred to as "PEG-2") 43.4 parts by mass, HEA9 parts by mass, 2,6-II -2 parts by mass of third butylcresol and 0.3 parts by mass of p-methoxyphenol. After the temperature was raised until the temperature in the reaction vessel became 40 ° C, 102 parts by mass of IPDI was added. Then, 0.1 part by mass of dioctyltin dineodecanoate was added, and the temperature was raised to 80 ° C. over 1 hour. Thereafter, it was held at 80 ° C. for 12 hours. After confirming that all isocyanate groups had disappeared, it was cooled to obtain a urethane acrylate (X-2). The urethane equivalent of the urethane acrylate (X-2) obtained was 7,023, and the weight average molecular weight was 19,000.

[Synthesis Example 3] <Synthesis of urethane acrylate (X-3)> In a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, 351 parts by mass of PTMG1000 and 51.4 parts by mass of PEG- 1. 5.7 parts by mass of HEA, 2 parts by mass of 2,6-di-tert-butylcresol, and 0.3 parts by mass of p-methoxyphenol. After the temperature was raised until the temperature in the reaction vessel became 40 ° C, 104 parts by mass of IPDI was added. Then, 0.1 part by mass of dioctyltin dineodecanoate was added, and the temperature was raised to 80 ° C. over 1 hour. It was then held at 80 ° C. for 12 hours. After confirming that all isocyanate groups had disappeared, it was cooled to obtain a urethane acrylate (X-3). The urethane equivalent of the obtained urethane acrylate (X-3) was 10,431, and the weight average molecular weight was 21,000.

[Synthesis Example 4] <Synthesis of urethane acrylate (X-4)> Polypropylene glycol (quantity average molecular weight; 3,000, hereinafter abbreviated as hereinafter) was added to a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer. "PPG3000") 180 parts by mass, 143 parts by mass of PTMG1000, 109 parts by mass of PEG-1, 6 parts by mass of HEA, 2 parts by mass of 2,6-di-tert-butylcresol, and 0.3 parts by mass of p-methoxyl Based phenol. After the temperature in the reaction vessel was raised to 40 ° C, 105 parts by mass of IPDI was added. Then, 0.1 mass part of dioctyltin dineodecanoate was added, and it took 1 hour to heat up to 80 degreeC. Thereafter, it was kept at 80 ° C. for 12 hours, and it was confirmed that all isocyanate groups disappeared, and then cooled to obtain a urethane acrylate (X-4). The urethane equivalent of the obtained urethane acrylate (X-4) was 10,507, and the weight average molecular weight was 26,000.

[Synthesis Example 5] <Synthesis of urethane acrylate (X-5)> 442 parts by mass of Duranol T-5652 and polyethylene glycol were added to a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer. ("Ymer N120" manufactured by Perstorp, number average molecular weight; 1,000) 246 parts by mass, 9.5 parts by mass of HEA, 2 parts by mass of 2,6-di-tert-butylcresol, and 0.3 parts by mass of p-methoxyphenol. After the temperature was raised until the temperature in the reaction vessel became 40 ° C, 102 parts by mass of IPDI was added. Then, 0.1 part by mass of dioctyltin dineodecanoate was added, and it took 1 hour to raise the temperature to 80 ° C. Thereafter, it was held at 80 ° C. for 12 hours, and after confirming that all isocyanate groups had disappeared, it was cooled to obtain a urethane acrylate (X-5). The urethane equivalent of the obtained urethane acrylate (X-5) was 9,771, and the weight average molecular weight was 20,000.

[Synthesis Example 6] <Synthesis of urethane acrylate (X-6)> To a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, 467 parts by mass of Duranol T-5651 and 9.6 parts by mass were added. 2 parts by mass of HEA, 2,6-di-tert-butylcresol, and 0.3 parts by mass of p-methoxyphenol. After the temperature in the reaction vessel was raised to 40 ° C, 101 parts by mass of IPDI was added. Then, 0.1 mass part of dioctyltin dineodecanoate was added, and it took 1 hour to heat up to 80 degreeC. Thereafter, it was held at 80 ° C. for 12 hours, and after confirming that all isocyanate groups had disappeared, it was cooled to obtain a urethane acrylate (X-6). The urethane equivalent of the obtained urethane acrylate (X-6) was 6,985, and the weight average molecular weight was 19,000.

[Synthesis Example 7] <Synthesis of urethane acrylate (X-7)> To a reaction vessel equipped with a stirrer, a reflux cooling tube, a nitrogen introduction tube, and a thermometer, 460 parts by mass of PTMG1000, 6.5 parts by mass of HEA, 2 2 parts by mass of 6,6-di-tert-butylcresol and 0.3 parts by mass of p-methoxyphenol. After raising the temperature in the reaction vessel to 40 ° C, 105 parts by mass of IPDI was added. Then, 0.1 mass part of dioctyltin dineodecanoate was added, and it took 1 hour to heat up to 80 degreeC. Thereafter, it was held at 80 ° C. for 12 hours, and after confirming that all isocyanate groups had disappeared, it was cooled to obtain a urethane acrylate (X-7). The urethane equivalent of the obtained urethane acrylate (X-7) was 10,208, and the weight average molecular weight was 22,000.

[Example 1] <Preparation of UV-curable adhesive composition> A reaction vessel equipped with a stirrer, a reflux cooling tube, and a thermometer was charged with 100 parts by mass of the aforementioned urethane acrylate (X-1), and butyl acrylic acid. 105 parts by mass of an ester (hereinafter abbreviated as "BA") and 10 parts by mass of dimethylacrylamide (hereinafter abbreviated as "DMAA") were stirred at 80 ° C until uniform. After cooling at room temperature, 3 parts by mass of 2,4,6-trimethylbenzylidenephenylphosphine oxide and decanedioic acid bis (2,2,6,6-tetramethyl-1) were added under stirring. -0.5 parts by mass of (octyloxy) -4-piperidinyl) ester, 0.5 parts by mass of triphenylphosphine, 0.1 parts by mass of 3-glycidoxypropyltriethoxysilane, and stirred until uniform . It was then filtered through a 200 mesh metal mesh to obtain a UV-curable adhesive composition.

[Examples 2 to 6, Comparative Examples 1 to 2] The types and amounts of the urethane (meth) acrylate and (meth) acrylic monomers used were changed as shown in Table 1. Example 1 was performed in the same manner to obtain an ultraviolet-curable adhesive composition.

[Manufacturing method of adhesive film] The surface of a polyethylene terephthalate film (release PET50) with a thickness of 50 μm that has been subjected to mold release treatment is coated with the ultraviolet curing adhesive obtained in the examples and comparative examples. The fat composition makes the film thickness after UV irradiation be 175 μm, and sticks to the release PET50. Thereafter, ultraviolet light was irradiated with a UV irradiation device, so that the cumulative light amount of the wavelength in the UV-A region after the release of the PET50 was 1 J / cm ² , and an adhesive film was prepared.

[Measurement method of adhesive force] One side of the adhesive film made by the above method was bonded to a polyethylene terephthalate film (PET75) with a thickness of 75 μm, and a PET75 substrate was bonded to one side Adhesive film. The test piece was cut into a width of 25 mm. This test piece was affixed to a glass plate and a polycarbonate (PC) plate which were to-be-adhered bodies by 2 kg rolls and 2 times back and forth, respectively. After 1 hour of attachment, the 180-degree peel strength was measured in a gas environment at 23 ° C. and a humidity of 50%, which was defined as the adhesive force.

[Evaluation method of moist heat and whitening resistance] One side of the adhesive film made by the method described above was bonded to a polyethylene terephthalate film (PET100) with a thickness of 100 μm, and made of PET100 on one side Laminated adhesive film. A test piece was cut into 50 mm in length and 40 mm in width and bonded to a glass plate with a 2 kg roller × back and forth twice. This test piece was measured for haze (%) with a turbidity meter "NDH5000" (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K7361-1-1997, and this was used as an initial value. Then, this test piece was placed in a gas environment at 85 ° C. and a humidity of 85% for 10 minutes, and then taken out, and within 10 minutes after removal, the turbidity meter “NDH5000” (manufactured by Nippon Denshoku Industries Co., Ltd.) was based on JISK7361-1. -1997 Determination of haze (%).

[Evaluation method of resistance to moist heat and yellowing] 者 One side of the adhesive film made by the method described above was attached to a glass plate, and another piece of release PET50 was peeled as a test piece. This test piece was measured for yellowness (b *) with a light source C, a field of view of 2 °, and a spectrophotometer "CM-5000d" (manufactured by Konica Minolta sensing Co., Ltd.) in accordance with JIS K7105-1981. The yellowness (b *) was similarly measured after the test piece was left in a gas environment at 80 ° C. and a humidity of 85% for 500 hours.

【Table 1】

The translations in Tables 1 and 2 are explained. ACMO; Acrylofluorenylphosphonoline NOA; n-octyl acrylate IOA; isooctyl acrylate TDA; tridecyl acrylate CHA; cyclohexyl acrylate IBXA; isofluorenyl acrylate

It is understood that the adhesive obtained by using the ultraviolet-curable adhesive composition of the present invention is excellent in adhesion, moist heat whitening resistance, and moist heat yellowing resistance.

On the other hand, it can be seen that Comparative Example 1 is a state in which polyethylene glycol is not used as a raw material of the urethane (meth) acrylate, and it has poor moist-heat whitening resistance.

Comparative Example 2 does not use polyethylene glycol as a raw material for the urethane (meth) acrylate, and uses a large amount of ACMO with high yellowing as a (meth) acrylic monomer, which has poor resistance to wet heat yellowing.

Claims (3)

A UV-curable adhesive composition, comprising: a urethane (meth) acrylate (X); a polyol (a) containing a polyethylene glycol (a1); and a polyisocyanate (b) ), And a (meth) acrylic compound (c) having a hydroxyl group or an isocyanate group; (meth) acrylic monomer (Y); and a photopolymerization initiator (Z); the (methyl) The content of the acrylic monomer (Y) is in the range of 30 to 200 parts by mass based on 100 parts by mass of the urethane (meth) acrylate (X); in the (meth) acrylic monomer (Y) The content of the (meth) acrylic monomer having a nitrogen atom is 40% by mass or less based on the total amount of the (meth) acrylic monomer (Y); the amount of the polyethylene glycol (a1) used is The range of 1 to 60% by mass in the polyol (a). For example, the ultraviolet curable adhesive composition of the first patent application range, wherein the number average molecular weight of the polyethylene glycol (a1) is in the range of 200 to 5,000. An adhesive, which is characterized in that it is obtained by using a UV-curable adhesive composition such as the item 1 or 2 of the patent application.