JP5817354B2 - Resin composition for UV curable adhesive, adhesive - Google Patents

Description

  The present invention relates to a resin composition for an ultraviolet curable pressure-sensitive adhesive and a pressure-sensitive adhesive that are excellent in polymerizability, adhesion to a substrate, and water resistance.

  In optical related products such as touch panels and liquid crystal displays, a large number of optical members having various types of materials and shapes are used in accordance with their higher functions.

  For bonding optical members as described above, a pressure-sensitive adhesive has been conventionally used. However, a pressure-sensitive adhesive having excellent adhesion is demanded from the industry regardless of the material and shape of the part.

  Further, in the manufacturing scene of the optical related product, in recent years, improvement of productivity of the final product has become a big issue. This is because a conventionally used pressure-sensitive adhesive usually contains a solvent such as a solvent or water, so that the solvent contained in the pressure-sensitive adhesive is removed after the pressure-sensitive adhesive is applied to the surface of the substrate. The process took a lot of time and contributed to the reduction in production efficiency of the final product.

  As a pressure-sensitive adhesive capable of improving the production efficiency of the product, an ultraviolet curable pressure-sensitive adhesive is known. Since the ultraviolet curable pressure-sensitive adhesive usually does not contain a solvent such as a solvent or water, there is a feature that a step of removing the solvent is not required when forming the pressure-sensitive adhesive layer.

  As a pressure-sensitive adhesive capable of improving the production efficiency of the final product as compared with the conventional one, for example, 100 parts of a monomer having an unsaturated double bond has a urethane bond and an unsaturated double bond at the polymer terminal. A pressure-sensitive adhesive composition containing 5 to 200 parts by mass of a high molecular weight polymer having a weight average molecular weight of 20,000 or more having a bond is known (for example, see Patent Document 1).

  However, the pressure-sensitive adhesive composition may not exhibit sufficient adhesion depending on the material of the base material to be used, and further, when used under wet heat conditions such as an optical member, etc. There was a problem of causing a decrease in adhesion (low water resistance).

Here, in the field of solvent-based and water-based pressure-sensitive adhesives, it is generally well known that a tackifier (tackfire) is added to a pressure-sensitive adhesive resin composition as a means for improving adhesion to a substrate. ing.
However, it is generally known that also in solvent-based and water-based pressure-sensitive adhesives, the polymerizability of the resin deteriorates when polymerized in the presence of a tackifier. Therefore, when the tackifier is added to the UV curable adhesive that is polymerized during UV irradiation, the adhesion to the substrate is expected to improve, but the polymerizability deteriorates, and the adhesive is retained due to this. It was easily imagined that it would cause problems such as deterioration of strength and heat resistance.

  As described above, in the field of UV curable pressure-sensitive adhesives that can improve production efficiency, materials that satisfy polymerizability, adhesion to substrates, and water resistance have been required, but have not yet been found. Is the actual situation.

JP 2006-104296 A

  The problem to be solved by the present invention is excellent polymerization without hindering polymerization, excellent adhesion at a level that does not cause peeling over time to substrates made of various materials and shapes, and used under wet heat conditions It is to provide an ultraviolet curable pressure-sensitive adhesive resin composition having excellent water resistance that does not lower the adhesion even when it is applied.

In the course of diligent research to solve the above-mentioned problems, the present inventors first focused on urethane (meth) acrylate resins and (meth) acrylic monomers, and advanced the research.
However, various studies have been conducted on the composition of the urethane (meth) acrylate resin and the (meth) acrylic monomer, but no method for solving the above problem has been found.
Therefore, the present inventors first focused on tackifiers for the purpose of improving adhesion, and conducted earnest research.
However, when a terpene tackifier that is commonly used for acrylic adhesives is used, the compatibility with the urethane (meth) acrylate resin is poor, and adhesion and water resistance are reduced. I understood it.
Then, the present inventors next examined the use of a polymerized rosin-based tackifier which is also often used for an acrylic pressure-sensitive adhesive, but found that the polymerizability was poor.
From this result, the present inventors considered that the double bond in the tackifier caused a radical termination reaction, and polymerization inhibition of the urethane (meth) acrylate resin occurred, and then there was no double bond (or Attempts to use a hydrogenated rosin-based tackifier.
However, in such a case, although the polymerizability is certainly improved, an adhesive that satisfies the adhesion to the substrate and the water resistance cannot be obtained.
Therefore, the present inventors have advanced earnestly researched on the polymerizability by ultraviolet rays and the physical properties of adhesives by combining various tackifiers and urethane (meth) acrylate resins.
As a result, among various tackifiers, only when a specific tackifier is used, regardless of the composition of the urethane (meth) acrylate resin and (meth) acrylic monomer, the polymerizability, It has been found that a resin composition for an ultraviolet curable pressure-sensitive adhesive that satisfies all adhesion and water resistance can be obtained.

  That is, the present invention is a urethane (meth) acrylate resin (A), (meth) obtained by reacting a polyol (a), a polyisocyanate (b), and a hydroxyl group-containing (meth) acrylic compound (c). In the resin composition for ultraviolet curable pressure-sensitive adhesive containing the acrylic monomer (B) and the photopolymerization initiator (C), selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, indene and isopropenyltoluene One or more unsaturated aromatic compounds (d-1) and one or more unsaturated aliphatic compounds (d-2) selected from the group consisting of isobutylene, butadiene, isoprene, piperylene and dicyclopentadiene. The present invention provides a resin composition for an ultraviolet curable pressure-sensitive adhesive, which further contains a tackifier (D) obtained by the reaction.

  The resin composition for an ultraviolet curable pressure-sensitive adhesive of the present invention can provide a pressure-sensitive adhesive excellent in polymerizability, adhesion to a substrate, and water resistance by using the specific tackifier. Moreover, according to the resin composition for ultraviolet curable adhesives of this invention, since it has the outstanding polymerizability, it is excellent also in holding power and can manufacture an adhesive easily by ultraviolet irradiation. Therefore, the adhesive comprising the resin composition for ultraviolet curable adhesive of the present invention can be suitably used as an adhesive used for an optical member.

  The resin composition for an ultraviolet curable pressure-sensitive adhesive of the present invention includes the urethane (meth) acrylate resin (A), the (meth) acrylic monomer (B), the photopolymerization initiator (C), and the tackifier. (D) and other additives as required.

  The resin composition for an ultraviolet curable pressure-sensitive adhesive includes the urethane (meth) acrylate resin (A), the (meth) acrylic monomer (B), the photopolymerization initiator (C), and the tackifier (D ) And additives may be dissolved or dispersed in a solvent such as an organic solvent or an aqueous medium, but the urethane (meth) acrylate resin in the (meth) acrylic monomer (B). When (A), the photopolymerization initiator (C), the previous tackifier (D), etc. are dissolved or dispersed, it is included in the adhesive when the laminate is produced by laminating the substrates. The step of removing the solvent to be removed is unnecessary, and the production efficiency of the laminate can be improved.

  Next, the urethane (meth) acrylate resin (A) used in the present invention will be described.

  The urethane (meth) acrylate resin (A) is obtained by reacting a polyol (a), a polyisocyanate (b), and a hydroxyl group-containing (meth) acrylic compound (c).

  The urethane (meth) acrylate resin (A) has a (meth) acryl group that allows radical polymerization to proceed by light irradiation, heating, or the like. The equivalent weight of the (meth) acrylic group is preferably in the range of 4000 to 9000, from the viewpoint of further improving the adhesion and holding power and forming a pressure-sensitive adhesive layer having good transparency. More preferably, it is -8000. The equivalent weight of the (meth) acryl group is the total mass of the polyol (a), the polyisocyanate (b), and the hydroxyl group-containing (meth) acryl compound (c), and the urethane (meth) acrylate. The value divided by the equivalent of the (meth) acryl group present in the resin (A) is shown.

  The urethane (meth) acrylate resin (A) has a weight average molecular weight of 1000 to 50000 from the viewpoint of improving the balance between excellent adhesion and holding power and imparting good coating workability. Those having a weight average molecular weight of 10000 to 25000 are more preferable, and the range of 12000 to 25000 is particularly preferable. In addition, the weight average molecular weight of the said urethane (meth) acrylate resin (A) is the value calculated | required by polystyrene conversion using the gel permeation chromatography (GPC).

  Although it does not specifically limit as said polyol (a), Polyester polyol, polyether polyol, polycarbonate polyol, polyacryl polyol, etc. can be used, These may be used individually or in combination of 2 or more types. . Especially, it is preferable to use polyether polyol and polycarbonate polyol from a viewpoint which can improve the outstanding adhesiveness and holding power more, and can further improve the durability of an adhesive film, especially water resistance.

  Examples of polyether polyols that can be used in the polyol (a) include 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. Products, polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran, modified polytetramethylene glycol copolymerized with tetrahydrofuran and alkyl-substituted tetrahydrofuran, or modified polytetramethylene copolymerized with neopentyl glycol and tetrahydrofuran Glycol.

  Examples of the compound having two or more active hydrogens include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, and 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, 2-methyl-1,8-octanediol, 2- Relatively low molecular weight dihydroxy compounds such as ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, hydroquinone, resorcin, bisphenol A, bisphenol F, 4,4′-bisphenol, , 2-cyclobutanediol, 1,3-cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, 1,4-cyclohexanedimethanol, hydroxypropylcyclohexanol, tricyclo [5,2,1, 0,2,6] decane-dimethanol, bicyclo [4,3 0] -nonanediol, dicyclohexanediol, tricyclo [5,3,1,1] dodecanediol, bicyclo [4,3,0] nonanedimethanol, tricyclo [5,3,1,1] dodecane-diethanol, hydroxy Propyltricyclo [5,3,1,1] dodecanol, spiro [3,4] octanediol, butylcyclohexanediol, 1,1'-bicyclohexylidenediol, cyclohexanetriol, hydrogenated bisphenol A, 1,3- Cycloaliphatic polyols such as adamantanediol, polyether polyols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and polyester polyols such as polyhexamethylene adipate, polyhexamethylene succinate and polycaprolactone Glycerin, diglycerin, trimethylolpropane, ditrimethylolpropane, tritrimethylolpropane, 1,2,6-hexanetriol, triethanolamine, triisopropanolamine, pentaerythritol, dipentaerythritol, sorbitol, saccharose, ethylenediamine N-ethyldiethylenetriamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,2-diaminobutane, 1,3-diaminobutane, 1,4-diaminobutane, diethylenetriamine, phosphoric acid, acidic phosphate ester, etc. Can be used.

  Among these, it is more preferable to use an aliphatic polyether polyol from the viewpoint of imparting good adhesive properties, and it is particularly preferable to use polytetramethylene glycol obtained by ring-opening polymerization of tetrahydrofuran.

  As the polycarbonate polyol that can be used for the polyol (a), for example, a polycarbonate polyol and / or phosgene that is obtained by reacting the compound (a-1) having two or more active hydrogens is used. Can do.

  As the carbonate ester, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate and the like can be used.

  As the polyol (a), other active hydrogen-containing chain extenders may be used in combination with the polyester polyol, polyether polyol, polycarbonate polyol, polyacryl polyol and the like as described above.

  Examples of the other active hydrogen-containing chain extender include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, and 3-methyl- 1,5-pentanediol, 1,6-hexanediol, 3,3′-dimethylol heptane, 1,4-cyclohexanedimethanol, neopentyl glycol, 3,3-bis (hydroxymethyl) heptane, diethylene glycol, diethylene glycol Polyhydric alcohols such as propylene glycol, glycerin, trimethylolpropane, sorbitol, hydroquinone diethylol ether, ethylenediamine, propylenediamine, hexamethylenediamine, trimethylhexamethylenediamine, isophoronediamine, 4,4'-dicyclohexylmethane Amine, diaminocyclohexane, can be used in combination or two or more methyl-diaminocyclohexane, and the like polyvalent amines such as norbornene diamine.

  The hydroxyl value of the polyol (a) is preferably 30 to 230 mgKOH / g, more preferably 50 to 230 mgKOH / g, from the viewpoint of adhesion and the like. In addition, the hydroxyl value of the said polyol (a) shows the value which measured based on JISK0070.

  Examples of the polyisocyanate (b) include aromatic diisocyanates such as xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, 4,4 ′. -Aliphatic or aliphatic cyclic structure-containing diisocyanates such as dicyclohexylmethane diisocyanate, diisocyanate methylcyclohexane, and tetramethylxylylene diisocyanate can be used alone or in combination of two or more. Among them, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate is used from the viewpoint of using an aliphatic cyclic structure-containing diisocyanate to improve adhesion, holding power, and heat-resistant yellowing. It is more preferable to use diisocyanate methylcyclohexane.

  The hydroxyl group-containing (meth) acrylic compound (c) is used for introducing a (meth) acrylic group into the urethane (meth) acrylate resin (A), and can react with an isocyanate group. The one containing is used.

  Examples of the hydroxyl group-containing (meth) acrylic compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl. Hydroxyl group-containing (meth) acrylic acid alkyl ester such as (meth) acrylate and 6-hydroxyhexyl acrylate, hydroxyl group such as trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate Containing polyfunctional (meth) acrylate, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate and the like can be used. Among these, from the viewpoint of easy availability of raw materials, polymerizability, and adhesive physical properties, it is more preferable to use a hydroxyl group-containing acrylic acid alkyl ester, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are particularly preferable. .

  As a method for producing the urethane (meth) acrylate resin (A), for example, after charging the polyol (a) and the hydroxyl group-containing (meth) acrylic compound (c) in a reaction system without solvent, An isocyanate group is formed at the molecular terminal by supplying the polyisocyanate (b), mixing and reacting it, or reacting the polyol (a) with the polyisocyanate (b) in the absence of a solvent. Examples thereof include a method of producing a urethane prepolymer having a hydroxyl group-containing (meth) acrylic compound (c), mixing, and reacting. In any case, the reaction is preferably carried out under a condition of 20 to 120 ° C. for about 30 minutes to 24 hours.

  The urethane (meth) acrylate resin (A) may be produced in the presence of an organic solvent or an aqueous medium. Furthermore, it may be produced in the presence of a (meth) acrylic monomer (B) described later, instead of an organic solvent or an aqueous medium. In particular, when manufacturing a laminate, it is not necessary to remove the organic solvent or aqueous medium and the manufacturing process can be simplified. From the viewpoint of suppressing viscosity in the absence of solvent or in the reaction system, (meth) acrylic It is preferable to carry out in the presence of the monomer (B).

  The reaction of the polyol (a), the polyisocyanate (b), and the hydroxyl group-containing (meth) acrylic compound (c) results in the hydroxyl group of the polyol (a) and the hydroxyl group-containing (meth) acrylic compound (c). Equivalent ratio of the total amount of hydroxyl groups possessed and the isocyanate group possessed by the polyisocyanate (b) [isocyanate groups / total amount of hydroxyl groups] = 0.75 to 1.00, urethane obtained (meta) It is preferable for controlling the molecular weight of the acrylate resin (A), and more preferably in the range of 0.79 to 0.95. The reaction may be carried out when the equivalent ratio exceeds 1, but in that case, an alcohol such as methanol is used for the purpose of deactivating the terminal isocyanate group of the urethane (meth) acrylate resin (A). It is preferable. In that case, the total amount of the hydroxyl group of the polyol (a), the hydroxyl group of the hydroxyl group-containing (meth) acrylic compound (c) and the hydroxyl group of the alcohol, and the equivalent ratio of the polyisocyanate group [isocyanate group / It is preferable to adjust the total amount of hydroxyl groups] to be within the above range.

  Moreover, as alcohol which can be used in order to inactivate the terminal isocyanate group of the said urethane (meth) acrylate resin (A), monofunctional alcohols, such as methanol, ethanol, a propanol, a butanol, 1, 2, for example, -Bifunctional alcohols composed of primary and secondary hydroxyl groups such as propylene glycol and 1,3-butylene glycol may be used.

  Moreover, when manufacturing urethane (meth) acrylate resin (A), you may use a polymerization inhibitor, a urethanization catalyst, etc. as needed.

  Examples of the polymerization inhibitor include 3,5-bismutual butyl-4-hydroxytoluene, hydroquinone, methyl hydroquinone, hydroquinone monomethyl ether (methoquinone), para-tertiary butyl catechol methoxyphenol, 2,6-ditertiary butyl cresol. Phenothiazine, tetramethylthiuram disulfide, diphenylamine, dinitrobenzene and the like can be used.

  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, and organometallic compounds such as dibutyltin laurate. Can be used.

  Next, the (meth) acryl monomer (B) used by this invention is demonstrated.

  The (meth) acrylic monomer is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, ( (Meth) butyl acrylate, (meth) acrylic acid isobutyl, (meth) acrylic acid pentyl, (meth) acrylic acid isopentyl, (meth) acrylic acid hexyl, (meth) acrylic acid heptyl, (meth) acrylic acid isoheptyl, (meta ) Octyl acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, hexadecyl (meth) acrylate, 2-methylbutyl (meth) acrylate, (Meth) acrylic acid-2-methylpentyl, (meth) acrylic acid-2- Butyl butyl, 2-ethylhexyl (meth) acrylate, trimethylmethyl (meth) acrylate, isotetradecyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, ( (Meth) acrylate 3-methoxybutyl, (meth) acrylate 2-ethoxyethyl, (meth) acrylate 2-ethoxypropyl, (meth) acrylate 2-ethoxybutyl, (meth) acrylate tetrahydrofurfuryl, (meth) ) Isobornyl acrylate, cyclohexyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, (meth ) -2-hydroxyethyl acrylate, (meth) 3-hydroxypropyl crylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate , Dimethylaminoethyl (meth) acrylate, N-methylol (meth) acrylamide, (meth) acrylonitrile, (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) Acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide methyl chloride quaternary salt, (meth) acryloylmorpholine, isopropyl (meth) acrylamide, N- (meth) acryl Royloxyethyl hexahydrophthalimide, hydroxyethyl (meth) acrylamide, glycidyl (meth) acrylate, ethyl carbitol (meth) acrylate, trifluoromethyl methyl (meth) acrylate, 2-trifluoromethyl (meth) acrylate Ethyl, 2-perfluoroethylethyl (meth) acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth) acrylate, 2-perfluoroethyl (meth) acrylate, perfluoro (meth) acrylate Methyl, (meth) acrylic acid diperfluoromethyl methyl, (meth) acrylic acid 2-perfluoromethyl-2-perfluoroethyl ethyl, (meth) acrylic acid 2-perfluorohexyl ethyl, (meth) acrylic acid 2- Perfluorodecylethyl, (meta 2-perfluorohexadecyl ethyl acrylate, pentaerythritol tri (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, isoamyl (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, Rosin epoxy acrylate and the like can be used, and these may be used alone or in combination of two or more.

  Among these, it is more preferable to use an acrylic monomer from the viewpoint that the radical termination reaction due to ultraviolet rays hardly occurs and the polymerizability can be further improved, and acryloylmorpholine, dimethylacrylamide, dimethylaminopropylacrylamide, N-acryloyloxyethyl. Use hexahydrophthalimide, butyl acrylate, 2-ethylhexyl acrylate, 2-methoxyethyl acrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, cyclohexyl acrylate, isobornyl acrylate, rosin epoxy acrylate Is more preferable from the viewpoint of further improving the physical properties of the adhesive, acryloylmorpholine, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, acrylic acid Soboroniru, rosin epoxy acrylate is particularly preferred.

  In the present invention, other vinyl monomers may be used in combination with the (meth) acrylic monomer as long as the effects of the present invention are not impaired.

  Examples of the other vinyl monomers include styrene monomers such as styrene, p-methylstyrene, ethylstyrene, propylstyrene, isopropylstyrene, and p-tert-butylstyrene, vinyl acetate, vinyl propionate, and vinyl pivalate. And vinyl monomers such as

  The amount of the (meth) acrylic monomer (B) used is 30 to 200 from the viewpoint of achieving both excellent adhesion and holding power with respect to 100 parts by mass of the urethane (meth) acrylate resin (A). It is preferably used in the range of part by mass, more preferably in the range of 40 to 150 parts by mass, and particularly preferably in the range of 50 to 130 parts by mass.

  Next, the photopolymerization initiator (C) used in the present invention will be described.

  The photopolymerization initiator (C) generates radicals by light irradiation, heating, or the like, and initiates radical polymerization of the urethane (meth) acrylate resin (A) or the (meth) acrylic monomer (B). It is.

  Examples of the photopolymerization initiator include 4-phenoxydichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy- 2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-methyl- [4- (methylthio) phenyl]- Acetophenones such as 2-morpholino-1-propanone and 2,2-dimethoxy-2-phenylacetophenone; benzoins such as benzoin, benzoin methyl ether, benzoin isoethyl ether, benzoin isopropyl ether and benzoin isobutyl ether; benzopheno Benzophenones such as benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, 3,3′-dimethyl-4-methoxybenzophenone; thioxanthone, 2-chloro Thioxanthones such as thioxanthone, 2,4-dichlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone; 4,4′-dimethylaminothioxanthone (Also known as Minerals ketone), 4,4′-diethylaminobenzophenone, α-acyloxime ester, benzyl, methylbenzoylformate (“Biacure 55”), Anthraquinones such as 2-ethylanthraquinone; 2,4,6-trimethylbenzoyldiphenylphosphine oxide (“Lucirin TPO”), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (“IRGACURE819”), etc. 3,3 ′, 4,4′-tetra (tert-butyloperoxycarbonyl) benzophenone [“BTTB” manufactured by NOF Corporation], acrylated benzophenone, and the like can be used. .

  As the photopolymerization initiator, adhesion and holding power can be further improved, and the adhesive layer can be prevented from discoloring over time. The urethane (meth) acrylate resin, the (meth) acrylic monomer, which will be described later 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2, 4, 6 from the viewpoint of further improving the compatibility with the tackifier (D) and the polymerizability It is preferable to use -trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. Among them, one or two of the 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Among bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, it is preferable to use one or a combination of two.

  In addition, one or two of the 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis Of the (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, when one or two are used in combination, the urethane (meth) acrylate resin used in the present invention, the (meth) acrylic monomer From the viewpoint of further improving the compatibility with the tackifier (D) and the polymerizability described later, among 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone, 1 or 2 and 2,4,6-trimethylbenzoyldiphenylphosphine oxide More preferably, one or two of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide are used in a mass ratio of 20/80 to 80/20, and 45/55 to 65 / 35 is particularly preferred.

  The photopolymerization initiator (C) is preferably used in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate resin (A). It is more preferable to use in the range of 15 parts by mass.

  Next, the tackifier (D) used in the present invention will be described.

Examples of the tackifier (D) include one or more unsaturated aromatic compounds (d-1) selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, indene and isopropenyltoluene, isobutylene, and butadiene. In order to solve the problems of the present invention, it is possible to use a compound obtained by reacting with one or more unsaturated aliphatic compounds (d-2) selected from the group consisting of isoprene, piperylene and dicyclopentadiene. It is essential.
Especially, it is more preferable to use what reacted isopropenyl toluene and 1, 3- butadiene from a viewpoint which can improve polymerizability, adhesiveness, and water resistance more.

  Moreover, when obtaining the said tackifier (D), from a viewpoint which can improve polymerizability, adhesiveness, and water resistance more, by said weight ratio, said (d-1) / (d-2) = 50 / 50- It is more preferable to make it react by 90/10, and 60 / 40-80 / 20 is still more preferable.

  As a method for producing the tackifier (D) (copolymerization reaction), for example, the unsaturated aromatic compound (d-1) and the unsaturated aliphatic compound (d-2) are converted into a catalyst (d -3) and polymerization in the presence of.

  Examples of the catalyst (d-3) include aluminum chloride, aluminum bromide, dichloromonoethylaluminum, titanium tetrachloride, tin tetrachloride, and boron trifluoride.

  The amount of the catalyst (d-3) used is 0.01 to 5% by weight, preferably 0.05 to 3% by weight, based on the total amount of the (d-1) and (d-2). .

  The copolymerization reaction is performed at a reaction temperature of -30 ° C to 250 ° C, more preferably -30 ° C to 50 ° C. The polymerization time is about 0.5 to 5 hours, but usually the polymerization reaction is almost completed in 1 to 2 hours. As the polymerization mode, either a batch system or a continuous system can be adopted. Further, multistage polymerization may be performed.

In addition, the copolymerization reaction is selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons for the purpose of removing reaction heat and suppressing the increase in viscosity of the reaction mixture. The polymerization reaction is preferably performed in at least one hydrocarbon solvent.
Examples of the hydrocarbon solvent include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, mesitylene, cumene, and cymene, aliphatic hydrocarbons such as pentane, hexane, heptane, and octane, and alicyclic rings such as cyclopentane, cyclohexane, and methylcyclohexane. Group hydrocarbons and the like can be used.
The amount of these hydrocarbon solvents used is preferably such that the initial concentrations of (d-1) and (d-2) are 10 to 80% by weight.

In addition, after completion | finish of the said copolymerization reaction, it is preferable to wash | clean a reaction system and to remove a catalyst residue. As the cleaning liquid, it is preferable to use an alkaline aqueous solution in which potassium hydroxide, sodium hydroxide or the like is dissolved, or an alcohol such as methanol.
After completion of the washing, it is preferable to obtain a tackifier (D) by distilling off unreacted monomers, hydrocarbon solvents and the like under reduced pressure.

  As a weight average molecular weight of the said tackifier (D) obtained by the above method, it is preferable that it is 1000-2000 from a viewpoint which can improve polymerizability, adhesiveness, and water resistance more. The weight average molecular weight of the tackifier (D) is a value obtained by gel conversion using gel permeation chromatography (GPC).

  Moreover, as a number average molecular weight of the said tackifier (D), it is preferable that it is 500-1000 from a viewpoint which can improve polymerizability, adhesiveness, and water resistance more. The number average molecular weight of the tackifier (D) is a value determined by polystyrene conversion using gel permeation chromatography (GPC).

  Further, the ratio between the important average molecular weight and the number average molecular weight of the tackifier (D) is Mw / Mn = 1.00 to 2.00 from the viewpoint of further improving the polymerizability, adhesion and water resistance. It is more preferable.

  The tackifier (D) preferably has a melt viscosity at 200 ° C. of 30 to 70 mPa · s from the viewpoint of further improving adhesion and water resistance. The melt viscosity of the tackifier (D) is a value measured with a B-type viscometer.

  Moreover, as a softening point of the said tackifier (D), 70-150 degreeC is preferable, 80-130 degreeC is more preferable, 90-105 degreeC is especially preferable. The softening point of the tackifier (D) is a value measured by the ring and ball method defined in JIS K2207.

  Moreover, as a glass transition temperature (Tg) of the said tackifier (D), it is more preferable that it is 20-40 degreeC. In addition, the glass transition temperature of the said tackifier (D) shows what is based on DMA using a dynamic viscoelasticity measuring apparatus. Specifically, the sample thickness is 2.0 mm, the width is 10.0 mm, the span length is 40 mm, the torsional vibration frequency is 1.0 Hz, the generated torque is 3 to 200 gf · cm, and the temperature rise rate is 5.0 ° C./min. And the temperature at the intersection of the tangent of the glass region and the tangent of the glass transition region in the storage elastic modulus (G ′)-temperature graph is calculated as the glass transition temperature.

  The tackifier (D) is used in an amount of 5 to 100 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate resin (A). It is preferable from a viewpoint which can improve more, and using in the range of 8-30 mass parts is more preferable.

  In addition, as said tackifier (D), "FTR-6100" (Mitsui Chemicals Co., Ltd. product) is available as a commercial item.

  Next, the ultraviolet curable adhesive resin composition of the present invention will be described.

  The resin composition for an ultraviolet curable pressure-sensitive adhesive according to the present invention is, for example, a urethane (meth) acrylate resin (A) produced alone, and then a (meth) acrylic monomer (B), a photopolymerization initiator (C). And, if necessary, a method of mixing a tackifier (D), or a urethane (meth) acrylate resin (A) in the presence of part or all of the (meth) acrylic monomer (B). And it can manufacture by methods, such as mixing a polymerization initiator (C) and the tackifier (D) if necessary.

  The ultraviolet curable pressure-sensitive adhesive resin composition obtained by the above method is not particularly limited, but is 500 to 20000 mPa · s from the viewpoint of good coating properties and good handling of the pressure-sensitive adhesive solution during coating. It is preferable that it is 1000-15000 mPa * s. In addition, the said viscosity shows the value measured with the B-type viscometer at 25 degreeC.

  Moreover, the resin composition for ultraviolet curable adhesives of this invention may contain another additive other than what was mentioned above.

  Examples of the other additives include light stabilizers, antioxidants, rust inhibitors, thixotropic agents, sensitizers, polymerization inhibitors, curing agents, curing accelerators, leveling agents, tackifiers, waxes, Thermal stabilizer, fluorescent whitening agent, foaming agent, thermoplastic resin, thermosetting resin, organic solvent, conductivity imparting agent, antistatic agent, moisture permeability improver, water repellent, hollow foam, crystal water-containing compound Flame retardants, water absorbents, moisture absorbents, deodorants, foam stabilizers, antifoaming agents, antifungal agents, antiseptics, algaeproofing agents, antiblocking agents, antihydrolysis agents, organic and inorganic water-soluble compounds, etc. Can be used.

  As the light-resistant stabilizer, for example, radical scavengers such as thiol-based, thioether-based, and hindered amine-based compounds, and ultraviolet absorbers such as benzophenone-based and benzoate-based compounds can be used. The above may be used in combination. Among them, from the viewpoint of maintaining compatibility between excellent adhesion and holding power and further improving the compatibility with the specific (meth) acrylic monomer used in the present invention and light stability, a hindered amine system Preference is given to using compounds.

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. Product of 2-aminoethanol (trade name: Tinuvin (registered trademark) 152 (manufactured by BASF Japan Ltd.)), bis (2,2,6,6-tetramethyl-1- ( Octyloxy) -4-piperidinyl) ester (trade name: Tinuvin (registered trademark) 123 (manufactured by BASF Corp.)), 1,1-dimethylethyl hydroperoxide and a reaction product of octane, and other amino ether groups Hindered amine compound, N-acetyl-3-dodecyl-1- (2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidi N-acetyl hindered amine compounds such as -2,5-dione (trade name: Hostavin (registered trademark) 3058 (manufactured by Clariant Japan)), bis (1,2,2,6,6-pentamethyl-4- Piperidyl) sebacate (trade name: SANOL LS765 (manufactured by BASF Japan Ltd.)), bis (1,2,2,6,6, -pentamethyl-4-piperidyl) {[3,5-bis (1,1- Dimethylethyl) -4-hydroxyphenyl] methyl} butyl malonate Trade name: Tinuvin (registered trademark) 144 (manufactured by BASF Japan Ltd.)), dimethyl succinate and 4-hydroxy-2,2,6,6-tetra Polymer of methyl-1-piperidineethanol (trade name: Tinuvin (registered trademark) 622LD (manufactured by BASF Japan Ltd.)), Rovandioic acid [{4-methoxyphenyl} methylene] -bis (1,2,2,6,6-pentamethyl-4-piperidyl) ester (trade name: Hostavin (registered trademark) PR-31 (Clariant Japan KK) ))-) N-alkyl hindered amine compounds and the like.
Among them, a hindered amine compound having an amino ether group is used from the viewpoint of maintaining the polymerizability, adhesion and water resistance and further improving the compatibility with other components used in the present invention and the light stability. It is particularly preferable to do this.

  The light-resistant stabilizer can be used in an amount of 0.01 to 10 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate resin (A) and can impart heat-resistant yellowing of the pressure-sensitive adhesive film. It is preferable from a viewpoint and it is more preferable to use in the range of 0.1-5 mass parts.

  Examples of the antioxidant include hindered phenolic compounds (primary antioxidants) that capture radicals generated by thermal degradation, and phosphorus-based and sulfur-based compounds (secondary oxidation) that decompose peroxides generated by thermal degradation. Inhibitor) and the like, and these can be used alone or in combination.

Examples of the hindered phenol compound include triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4hydroxyphenyl) propionate] (trade name: IRGANOX (registered trademark) 245 (BASF Japan). ), Pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (trade name: IRGANOX (registered trademark) 1010 (manufactured by BASF Japan Ltd.)), Octadecyl [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (trade name: IRGANOX (registered trademark) 1076 (manufactured by BASF Japan Ltd.)), thiodiethylene bis [3- (3 5-Di-tert-butyl-4-hydroxyphenyl) propionate (Trade name: IRGANOX (registered trade mark) 1035 (BASF Japan Ltd.), benzenepropanoic acid 3,5-bis (1,1-dimethylethyl) -4-hydroxy -C ₇ -C ₉ side chain alkyl Esters (trade name: IRGANOX (registered trademark) 1135 (manufactured by BASF Japan)), 4,6-bis (dodecylthiomethyl) -o-cresol (trade name: IRGANOX (registered trademark) 1726 (BASF Japan, Inc.) )), Reaction product of N-phenylbenzenamine and 2,4,4-trimethylpentene (trade name: IRGANOX (registered trademark) 5057 (manufactured by BASF Japan Ltd.)), 2-t-butyl-6 -(3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (trade name: Sumilizer ( Registered trademark) GM (manufactured by Sumitomo Chemical Co., Ltd.)), 3,9-bis [2- [3- (t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro [5.5] undecane (trade name: Sumilizer (registered trademark) GA-80 (manufactured by Sumitomo Chemical Co., Ltd.)), 2,6-di-tert-butyl-4 -Methylphenol (trade name: NOCRACK 200 (manufactured by Ouchi Shinsei Chemical Co., Ltd.)), 2,2'-methylenebis (4-methyl-6-tert-butylphenol) (trade name: NOCRACK NS-6 (Ouchi) Shinsei Chemical Industry Co., Ltd.)), 2,5-di-tert-amylhydroquinone (trade name: NOCRACK DAH (Ouchi Shinsei Chemical Industry Co., Ltd.)), and the like.

  Examples of the phosphorus compound include triphenylphosphine, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl phosphite, triphenyl phosphite, trisnonylphenyl phosphite, and tris. (2,4-dibutylphenyl) phosphite, tris (2,4-dibutyl-5-methylphenyl) phosphite, tris [2-tert-butyl-4- (3-butyl-4-hydroxy-5-methylphenyl) Thio) -5-methylphenyl] phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, di (tridecyl) pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite Bis (2,4-dibutylphenyl) pe Taerythritol diphosphite, bis (2,6-dibutyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4,6-tributylphenyl) pentaerythritol diphosphite, bis (2,4-dicumyl) Phenyl) pentaerythritol diphosphite, tetra (tridecyl) isopropylidene diphenol diphosphite, tetra (tridecyl) -4,4′-n-butylidenebis (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- 0-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] dioxaphosphine-6- Yl) oxy] ethyl) amine, phosphite of 2-ethyl-2-butylpropylene glycol and 2,4,6-tributylphenol.

  Examples of the sulfur compound include didodecyl-3,3′-thiopropionate, dilauryl-3,3′-thiodipropionate, laurylthiothiothionate, ditridecyl-3,3′-thiodipropionate. , Dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, tetrakis-methylene-3-laurylthiopropionate methane, distearyl-3,3′-methyl-3 , 3′-thiodipropionate, laurylstearyl-3,3′-thiodipropionate, bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-tert-butylphenyl] sulfide, β -Laurylthiopropionate, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzoy Imidazole, dioctadecyl 3,3'-thiodipropionate isethionate, and the like.

  Among these, it is possible to use a phosphorus compound from the viewpoint of maintaining the polymerizability, adhesion, and water resistance and further improving the compatibility with other components used in the present invention and the heat-resistant yellowing. Preferably, triphenylphosphine, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl phosphite, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4- Particular preference is given to using hydroxyphenyl) propionate.

  The amount of the antioxidant used is in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate resin (A). It is preferable from a viewpoint which can provide, and it is more preferable to use in the range of 0.1-5 mass parts.

  As the rust preventive, for example, triazole compounds, organic carboxylic acid amine salts, nitrite amine salts, phosphoric acid amine salts, amine carbonates, heterocyclic amines and the like can be used, and these can be used alone or in combination. May be used. Among them, the viewpoint of maintaining the polymerizability, adhesion, and water resistance, and further improving the compatibility with other components used in the present invention and the rust prevention property without impairing the light stability and heat yellowing resistance. Therefore, it is preferable to use a triazole compound.

  Examples of the triazole compound include 1- [bis (2-ethylhexyl) aminomethyl] benzotriazole, methylbenzotriazole, dimethylbenzotriazole, ethylbenzotriazole, ethylmethylbenzotriazole, diethylbenzotriazole, unsubstituted benzotriazole, 5-methyl-1H-benzotriazole, N, N-bis (2-ethylhexyl)-(4 or 5) -methyl-1H-benzotriazole-1-methylamine, triazole compound represented by the following general formula (1) Etc. can be used.

Wherein R1 and R2 are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, or the number of carbon atoms. Represents an aralkyl group having 7 to 13 carbon atoms, an aryl group having 6 to 10 carbon atoms, and a hydroxyl group.)

  As the triazole compound represented by the general formula (1), N, N-bis (2-ethylhexyl)-[(1,2,4-triazol-1-yl) methyl] amine and the like can be preferably used.

  The amount of the rust inhibitor used is preferably 0.001 to 5 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate resin (A) without deteriorating the adhesive properties. It is preferable from a viewpoint which can provide rust prevention property, and it is more preferable to use in the range of 0.01-2 mass parts.

  Examples of the sensitizer include biphenyl, 1,4-dimethylnaphthalene, 9-fluorenone, fluorene, phenanthrene, triphenylene, anthracene, 9,10-diphenylanthracene, 9,10-dimethoxyanthracene, and 9,10-diethoxy. Anthracene, 9,10-dipropoxyanthracene, 9,10-dibutoxyanthracene, benzophenone, 4,4′-dimethoxybenzophenone, acetophenone, 4-methoxyacetophenone, benzaldehyde and the like can be used.

  As the curing agent, polyisocyanate compounds typified by tolylene diisocyanate, adducts derived from hexamethylene diisocyanate, and nurate, polyfunctional epoxy compounds, melamine compounds, metal chelates, etc. should be used. Can do.

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

  As a method for curing the ultraviolet curable adhesive resin composition of the present invention, for example, a known ultraviolet light irradiation device such as a xenon lamp, a xenon-mercury lamp, a metal halide lamp, a high pressure mercury lamp, a low pressure mercury lamp, or the like is used. It can be cured by irradiating with predetermined ultraviolet rays.

Irradiation of the ultraviolet rays is preferably 50 to 5000 mJ / cm ^2, more preferably 100~3000mJ / cm ^2, particularly preferably it is in the range of 300~1500mJ / cm ^2. In addition, the ultraviolet irradiation amount was based on a value measured in a wavelength range of 300 to 390 nm using a UV checker UVR-N1 (manufactured by GS Yuasa Co., Ltd.).

  Moreover, when the resin composition for ultraviolet curable adhesives of this invention contains the said other additive, as needed, by heating at about 40-80 degreeC after the said ultraviolet irradiation, Curing may be further accelerated.

  The pressure-sensitive adhesive made of the resin composition for ultraviolet curable pressure-sensitive adhesive of the present invention can be suitably used as a pressure-sensitive adhesive used for an optical member because it has both excellent adhesion and holding power.

  As a suitable usage mode of the pressure-sensitive adhesive composed of the resin composition for ultraviolet curable pressure-sensitive adhesive of the present invention, for example, a pressure-sensitive adhesive for bonding upper and lower sheets used for a membrane sheet keyboard or a pressure-sensitive adhesive for fixing a frame of a liquid crystal display Use as an adhesive and an adhesive used for various labels.

  The thickness of the pressure-sensitive adhesive layer when the pressure-sensitive adhesive of the present invention is used in various applications can be selected from about 0.1 to 500 μm, although it varies depending on the application.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited only to these examples.
Further, in the present invention, unless otherwise specified, “part” is “part by mass” and “%” is “mass%”.

[Synthesis Example 1]
<Synthesis of urethane (meth) acrylate resin (A-1)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer, 465.9 parts of polytetramethylene glycol (hydroxyl value 112 mgKOH / g), 9.6 parts of 2-hydroxyethyl acrylate, 2,6- 1.7 parts of di-tertiary butyl-cresol and 0.3 part of p-methoxyphenol were added. After raising the temperature in the reaction vessel to 40 ° C., 101.5 parts of isophorone diisocyanate was added. Therefore, 0.06 part of dioctyltin dineodecanate was added and the temperature was raised to 80 ° C. over 1 hour. Then, after hold | maintaining at 80 degreeC for 12 hours and confirming that all the isocyanate groups have lose | disappeared, it cooled and obtained urethane (meth) acrylate resin (A-1). The obtained urethane (meth) acrylate resin (A-1) had an acrylic group equivalent weight of 7000 and a weight average molecular weight of 18,000.

[Example 1]
In a container equipped with a stirrer, a reflux condenser, and a thermometer, 100 parts of the urethane (meth) acrylate resin (A-1) obtained in Synthesis Example 1, 40 parts of butyl acrylate, 30 parts of acryloylmorpholine, FTR-6100 17 parts (Mitsui Chemical Co., Ltd., weight average molecular weight: 1154, number average molecular weight: 612, melt viscosity at 200 ° C .: 60 mPa · s) were added at a container internal temperature of 80 ° C. and stirred until uniform. Thereafter, the mixture was cooled to room temperature, and 4 parts of 2-hydroxy-2-methyl-1-phenylpropan-1-one and 3 parts of 2,4,6-trimethoxybenzoyldiphenylphosphine oxide were sequentially added under stirring. Stir until. Thereafter, the mixture was filtered through a 200 mesh wire mesh to obtain an ultraviolet curable adhesive resin composition.

[Comparative Examples 1-6]
Except having changed the kind of tackifier used as shown in Table 1, the resin composition for ultraviolet curable adhesives was obtained similarly to Example 1. FIG.

[Method for measuring weight average molecular weight and number average molecular weight]
The weight average molecular weight and number average molecular weight of the urethane (meth) acrylate resin (A-1) and FTR-6100 used in the examples were measured as follows.
(Measurement conditions and equipment)
Tosoh Co., Ltd. integrated GPC device: HLC-8220GPC
Detector: RI (Suggested refractometer)
Column: TSK-gel G5000HxL (7.8 × 300 mm) × 1
G4000HxL (7.8 × 300mm) × 1
G3000HxL (7.8 × 300mm) × 1
G2000HxL (7.8 × 300mm) × 1
Mobile phase: THF
Flow rate: 1.0 mL / min
Set temperature: 40 ° C
Injection volume: 100 μL (sample concentration: 0.4%)
Measure the weight average molecular weight and number average molecular weight in terms of polystyrene (*).
* Polystyrene: TSK standard polystyrene manufactured by Tosoh Corporation

[Method for producing adhesive film]
The ultraviolet curable pressure-sensitive adhesive resin compositions obtained in Examples and Comparative Examples were applied to the surface of a 75 μm thick polyethylene terephthalate film (PET75) so that the film thickness after UV irradiation was 22 μm. On the surface, a polyethylene terephthalate film (release PET50) having a thickness of 50 μm, which was different from the above and was subjected to release treatment, was bonded to the surface.
Subsequently, the adhesive film laminated | stacked through two polyethylene terephthalate films was produced by irradiating an ultraviolet-ray using the UV irradiation apparatus from the upper side of the said release PET50. The irradiation of the ultraviolet rays was performed under the condition that the integrated light quantity with a wavelength of 300 to 390 nm after passing through the release PET 50 was 1000 mJ / cm ² .

[Evaluation method of polymerizability]
Polymerizability was evaluated using the gel fraction of the pressure-sensitive adhesive. Here, the term “polymerizability” refers to the molecular weight of the polymer produced during UV irradiation, and a pressure-sensitive adhesive having a large value tends to form a crosslinked structure and exhibits a high gel fraction. Therefore, in order to facilitate the determination of the polymerizability, the types of urethane (meth) acrylate resin and (meth) acrylic monomer are fixed, the crosslink density is unified, and only the type of tackifier is changed. Then, the value of the gel fraction was measured to evaluate the polymerizability.
Specifically, a test piece was prepared by cutting the adhesive film into a size of 40 mm × 50 mm. Next, the mass (G1) before toluene immersion of the test piece from which the release PET was peeled and the mass (G0) of PET 75 having the above-mentioned size were measured and immersed in a toluene solution at room temperature for 24 hours. . And the toluene insoluble part of the test piece after immersion is isolate | separated by filtering with a 300 mesh metal-mesh, The mass (G2) of the residue after drying at 105 degreeC for 1 hour is measured, According to following formula (2) The gel fraction was determined.
Gel fraction (%) = [(G2) − (G0) / (G1) − (G0)] × 100 (2)
In addition, the thing whose gel fraction was 40% or more is "○"
What was less than 40% is "x"
It was evaluated.
Moreover, the thing with bad compatibility with a tackifier and urethane (meth) acrylate, and the thing which could not be evaluated after this was set to "-".

[Evaluation method of adhesion to substrate]
The adhesion to the substrate was evaluated by the adhesive strength.
Specifically, one release PET 50 constituting the pressure-sensitive adhesive film is peeled off, and a pressure-sensitive adhesive sheet is prepared by laminating polyethylene terephthalate (PET 75) having a thickness of 75 μm to the surface of the pressure-sensitive adhesive layer. Was cut to a width of 25 mm. Then, it was made to reciprocate by 2 kg rolls, and it was set as the test piece. After leaving the test piece for 1 hour, the peel strength (T-type peel force) was measured at 23 ° C. and 50% RH at a peel rate of 300 mm / min.

[Method of measuring holding force]
One release PET 50 constituting the pressure-sensitive adhesive film is peeled off, and the pressure-sensitive adhesive layer surface is laminated on a mirror-finished stainless steel plate so that the bonding area is 25 mm × 25 mm, and the atmosphere is 23 ° C. and 50% RH. They were pasted together by reciprocating 2 kg rolls twice.
Next, a 1 kg load is applied to the stainless steel plate in a 0 ° direction (shear direction) with respect to the test piece attached to the stainless steel plate in a 70 ° C. atmosphere until the test piece slips off the stainless steel plate. Was measured and the holding time was defined as holding power. Moreover, when it was hold | maintained after 24 hours, the holding time was made into 1440 minutes or more, the shift | offset | difference width from the initial sticking position was measured, and it described together.

[Evaluation method of water resistance]
The pressure-sensitive adhesive sheet after press-bonding obtained in [Method for evaluating adhesion to substrate] was immersed in water at 25 ° C. for 4 hours. After immersion, the peel strength (T-type peel force) was measured in the same manner as in [Method for evaluating adhesion to substrate], and the adhesive strength after immersion was determined.
The water resistance was judged by comparing the adhesive strength measured in the above [Method for evaluating adhesion to substrate] and the adhesive strength after immersion.
That is, the value of [Adhesive strength after immersion] / [Adhesive strength measured by the above [Method for evaluating adhesion to substrate]] × 100 (%)
85% or more: “○”
70% or more and less than 85%: “△”
Less than 70%: “×”
It was judged.

The abbreviations in Table 1 will be described.
“BA”; butyl acrylate “ACMO”; acryloylmorpholine “C-1”; 2-hydroxy-2-methyl-1-phenylpropan-1-one “C-2”; 2,4,6-trimethoxybenzoyl Diphenylphosphine oxide “Clearon K-100”; Terpene saturated resin aromatic modified product (manufactured by Yasuhara Chemical Co., Ltd.)
“Clearon K-4100”; Terpene saturated resin aromatic modified product (manufactured by Yasuhara Chemical Co., Ltd.)
"Halitac PCJ"; Polymerized rosin ester (Harima Kasei Co., Ltd.)
“Pine Crystal KE-395”; hydrogenated rosin ester (Arakawa Chemical Industries, Ltd.)
“FTR-0100”; α-methylstyrene homopolymer (manufactured by Mitsui Chemicals, Inc.)

Claims (7)

Urethane (meth) acrylate resin (A), (meth) acrylic monomer (B), which is a reaction product of polyol (a), polyisocyanate (b), and hydroxyl group-containing (meth) acrylic compound (c), And a photopolymerization initiator (C) -containing resin composition for an ultraviolet curable pressure-sensitive adhesive (excluding a (meth) acrylic polymer), wherein the polyol (a) is a polyether polyol and / or a polycarbonate polyol. Yes,
The photopolymerization initiator (C) is one of 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone, and 2,4,6-trimethylbenzoyldiphenylphosphine A combination of one of oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide,
One or more unsaturated aromatic compounds (d-1) selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, indene and isopropenyltoluene and isobutylene, butadiene, isoprene, piperylene and dicyclopentadiene A resin composition for an ultraviolet curable pressure-sensitive adhesive, further comprising a tackifier (D) which is a reaction product with one or more unsaturated aliphatic compounds (d-2) selected from the group. The resin composition for ultraviolet curable adhesives of Claim 1 whose said unsaturated aromatic compound (d-1) is isopropenyl toluene. The resin composition for ultraviolet curable adhesives of Claim 1 whose said unsaturated aliphatic compound (d-2) is 1, 3- butadiene. The resin composition for ultraviolet curable adhesives of Claim 1 whose weight average molecular weights of the said tackifier (D) are 1000-2000. The resin composition for ultraviolet curable adhesives of Claim 1 whose melt viscosity in 200 degreeC of the said tackifier (D) is 30-70 mPa * s. The adhesive which consists of a resin composition for ultraviolet curable adhesives of any one of Claims 1-5 . The pressure-sensitive adhesive according to claim 6 , which is used for an optical member.