JP5834606B2 - UV-curable adhesive resin composition, adhesive and laminate - Google Patents

Description

  The present invention relates to a resin composition for an ultraviolet curable pressure-sensitive adhesive having excellent adhesive strength, a pressure-sensitive adhesive, and a laminate.

  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 an excellent adhesive force is demanded from the industry regardless of the material 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.

  Examples of the pressure-sensitive adhesive having a level of adhesive strength that can be used in the production of the product and the like and capable of improving the production efficiency of the final product as compared with the conventional product include, for example, 100 parts of a monomer having an unsaturated double bond On the other hand, it has a weight average molecular weight of 20,000 or more and has a urethane bond and an unsaturated double bond at the polymer terminal, and contains 5 to 200 parts by mass. An adhesive composition is known (for example, refer to Patent Document 1).

  However, the pressure-sensitive adhesive composition may not exhibit a practically sufficient adhesive force depending on the material of the base material, and has a problem that the adhesive force is remarkably lowered particularly when used under wet heat conditions. .

JP 2006-104296 A

  The problem to be solved by the present invention is that it has excellent adhesive strength at a level that does not cause peeling over time to substrates made of various materials, and even when used under wet heat conditions It is providing the resin composition for ultraviolet curing adhesives which has the outstanding heat-and-moisture resistance which does not fall.

  The inventors of the present invention have made extensive research to solve the above problems, and have paid attention to the combination of a urethane (meth) acrylate resin and a (meth) acrylic monomer, and have advanced the research.

  First, the present inventors examined the polyol used for urethane (meth) acrylate resin. However, when a polyester polyol or a polyether polyol is used as the polyol, the moisture and heat resistance is poor or sufficient cohesive strength cannot be obtained due to insufficient cohesion.

  Therefore, the present inventors examined the use of polycarbonate polyol, which generally has a glass transition temperature higher than that of polyester polyol or polyether polyol, in order to improve heat resistance and adhesive strength.

  As a result, it was confirmed that the moisture and heat resistance was improved, but the adhesive strength was still insufficient.

  Therefore, the present inventors have studied a urethane (meth) acrylate resin and a (meth) acrylic monomer used in combination.

  As a result, it was found that when a single (meth) acrylic component was used as the (meth) acrylic monomer to be used, it was not possible to obtain a pressure-sensitive adhesive having both adhesive strength and holding power.

  Moreover, it was found that the control of the cohesive force due to the glass transition temperature of the (meth) acrylic monomer to be used is very important during further research. As a result, when a urethane (meth) acrylate resin using a polycarbonate polyol and a (meth) acrylic monomer capable of forming a copolymer having a specific glass transition temperature are used in combination, the adhesive strength and heat-and-moisture resistance are improved. It has been found that an excellent pressure-sensitive adhesive 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 an ultraviolet curable pressure-sensitive adhesive containing the acrylic monomer (B) and the photopolymerization initiator (C), the polyol (a) is a polycarbonate polyol, and the (meth) acrylic monomer ( B) is a combination of two or more, and the two or more (meth) acrylic monomers are capable of forming a copolymer having a glass transition temperature of 15 ° C. or lower. The resin composition for an ultraviolet curable pressure-sensitive adhesive, a pressure-sensitive adhesive comprising the same, and a laminate are provided.

  The pressure-sensitive adhesive composed of the ultraviolet curable pressure-sensitive adhesive resin composition of the present invention has excellent adhesive strength and holding power, and resistance to moist heat.

  The pressure-sensitive adhesive comprising 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. In particular, it can be suitably used for the production of touch panels, liquid crystal displays, plasma displays, organic EL, and the like.

  First, 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 achieving both excellent adhesive force and holding power and forming an adhesive layer with good transparency. More preferably, it is 5000 to 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.

  As said urethane (meth) acrylate resin (A), what has the weight average molecular weight of 5000-50000 from the viewpoint which can make the outstanding adhesive force and holding power compatible, and can provide favorable coating workability | operativity. It is preferable to use, more preferably one having a weight average molecular weight of 7000 to 25000, particularly preferably in the range of 10,000 to 23000. In addition, the weight average molecular weight of the said urethane (meth) acrylate resin (A) is the value calculated | required by styrene conversion using gel permeation chromatography (GPC).

  In the present invention, it is essential to use a polycarbonate polyol as the polyol (a) in order to obtain a pressure-sensitive adhesive having heat and moisture resistance.

  As said polycarbonate polyol, what is obtained by making carbonate (1) and / or phosgene react with the compound (a-1) which has the 2 or more active hydrogen mentioned later, for example can be used.

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

  Examples of the compound (a-1) having two or more active hydrogens capable of reacting with the carbonate ester or phosgene include, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1, 3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1, 5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11 -Undecanediol, 1,12-dodecanediol, 2-methyl-1 3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-propanediol, 3-methyl- Relatively low such as 1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, hydroquinone, resorcin, bisphenol A, bisphenol F, 4,4′-bisphenol Molecular weight dihydroxy compounds, 1,2-cyclobutanediol, 1,3-cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, 1,4-cyclohexanedimethanol, hydroxypropylcyclohexanol, tricyclo [5, 2, 1, 0, 2, ] 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, hydroxypropyltricyclo [5,3,1,1] dodecanol, spiro [3,4] octanediol, butylcyclohexanediol, 1,1′-bicyclohexylidenediol, Cycloaliphatic polyols such as cyclohexanetriol, hydrogenated bisphenol A, 1,3-adamantanediol, polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene adipate, polyhexamethylene succinate, Po Polyester polyols such as licaprolactone can be used.

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

  In the present invention, the composition of the polycarbonate polyol is not important, and it is very important that the resin composition for an ultraviolet curable adhesive of the present invention contains a carbonate bond structure.

  As content of the carbonate bond structure in the resin composition for ultraviolet curable adhesives of this invention, it is preferable that it is 4-40 mass% from a wet heat resistant viewpoint, and it is more preferably 6-32 mass%. preferable.

  In addition, as said polyol (a), if it is a range which does not impair the effect of this invention, you may use together polyether polyol, polyester polyol, polyacryl polyol, polybutadiene polyol, etc. with the said polycarbonate polyol.

  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 these, 4,4′-dicyclohexylmethane diisocyanate and isophorone diisocyanate are used from the viewpoint of using an aliphatic cyclic structure-containing diisocyanate to achieve both excellent adhesive strength and holding power and to improve heat-resistant yellowing. More preferably, cyclohexane diisocyanate or diisocyanate methylcyclohexane is used.

  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 curability by ultraviolet rays, it is more preferable to use a hydroxyl group-containing acrylic compound. From the viewpoint of easy availability of raw materials, curability, and good adhesive properties, 2-hydroxyethyl acrylate and Particular preference is given to using 4-hydroxybutyl acrylate.

  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 a combination of two or more (meth) acrylic monomers, and the two or more (meth) acrylic monomers have a glass transition temperature (Tg). A copolymer having a temperature of 15 ° C. or lower can be formed.
The glass transition temperature refers to the glass transition temperature when (meth) acrylic monomers are copolymerized to the last, and the glass transition temperature of the resin composition for an ultraviolet curable adhesive of the present invention. is not.
The glass transition temperature is preferably −50 ° C. or more and 15 ° C. or less, more preferably −40 ° C. or more and 10 ° C. or less, and −35 ° C. or more and 0 ° C. or less from the viewpoint of further improving the heat and moisture resistance and adhesive strength. Is particularly preferred.

  Further, in order for the (meth) acrylic monomer (B) to form a copolymer having a glass transition temperature of 15 ° C. or lower, a (meth) acryl capable of forming a homopolymer having a glass transition temperature of 15 ° C. or lower. It is essential to use a combination of at least one monomer (x) and at least one (meth) acrylic monomer (y) capable of forming a homopolymer having a glass transition temperature higher than 15 ° C. .

  Moreover, as said (meth) acryl monomer (B), it uses in the range whose mass ratio with said (x) and (y) is (x) / (y) = 90 / 10-40 / 60. Is preferable because good adhesive strength can be imparted. Moreover, it is more preferable that it is 85 / 15-45 / 55, and it is especially preferable to use it in the range of 80 / 20-40 / 60.

  Regarding the selection of the (meth) acrylic monomer (B) for forming a copolymer having a glass transition temperature of 15 ° C. or lower, the (meth) acrylic monomer (x) and the (meth) acrylic monomer (y ), The Tg of the copolymer (copolymer) composed of n types of monomers can be calculated using the following Fox formula (1).

1 / Tg = Σ (Wn / Tgn) (1)

Tg: Calculation of copolymer (copolymer) Tg (K)
Wn: weight fraction of monomer n (wt%)
Tgn: Tg (K) of homopolymer of monomer n

  As the Tg (Tgn) of the homopolymer used in the formula (1) of the Fox, Polymer Handbook (4th ed.) And (meth) acrylic monomer manufacturer homepage values are used.

  Examples of the (meth) acrylic monomer (x) capable of forming a homopolymer having a glass transition temperature of 15 ° C. or lower include, for example, methyl acrylate (Tg: 10 ° C.), ethyl acrylate (−24 ° C.), acrylic Propyl acid (-37 ° C), isopropyl acrylate (-6 ° C), butyl acrylate (-49 ° C), sec-butyl acrylate (-22 ° C), isobutyl acrylate (-24 ° C), 2-acrylic acid 2- Ethylbutyl (-50 ° C), n-pentyl acrylate (-57 ° C), hexyl acrylate (-57 ° C), 2-ethylhexyl acrylate (-50 ° C), heptyl acrylate (-60 ° C), octyl acrylate (-65 ° C), 2-octyl acrylate (-45 ° C), nonyl acrylate (-58 ° C), dodecyl acrylate (-3 ° C), 3-methoxy acrylate Chill (-56 ° C), 2-methoxyethyl acrylate (-50 ° C), 3-methoxypropyl acrylate (-75 ° C), 2-methoxybutyl acrylate (-32 ° C), 3-methylbutyl acrylate (- 45 ° C.), benzyl acrylate (6 ° C.), pentyl methacrylate (−5 ° C.), hexyl methacrylate (−5 ° C.), 2-ethylhexyl methacrylate (−10 ° C.) (above, Polymer Handbook (4th ed.)) Tg value reprinted), 2-hydroxyethyl acrylate (HEA; −15 ° C.), 2-hydroxypropyl acrylate (HPA; −7 ° C.), 4-hydroxybutyl acrylate (4HBA; −32 ° C.), acrylic Isooctyl acid (IOAA; -58 ° C), lauryl acrylate (LA; 15 ° C), stearyl acrylate (STA;- 58 ° C), tetrahydrofurfuryl acrylate (Biscoat # 150; -12 ° C), benzyl acrylate (Biscoat # 160; 6 ° C), ethyl carbitol acrylate (Biscoat # 190; -67 ° C), phenoxyethyl acrylate (Biscoat # 192; −22 ° C.) (Osaka Organic Chemical Co., Ltd., Tg value reprinted from HP), methoxypolyethylene glycol acrylate (EO 9 mol, AM-90G; −71 ° C.), phenoxypolyethylene glycol Acrylate (AMP-20GY; -8 ° C) (Sin Nakamura Chemical Co., Ltd., Tg value reprinted from the company's HP), isoamyl acrylate (IAA; -45 ° C), ethoxy acrylate-diethylene glycol (EC- A: -70 ° C.) (Kyoeisha Chemical Co., Ltd., the company's HP) Mentioned Tg values reprint), etc., they can be used in combination one kind or two or more kinds. Among them, it is preferable to use methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-methoxyethyl acrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and particularly acrylic acid. The use of butyl and 2-ethylhexyl acrylate is particularly preferable because excellent tackiness can be imparted.

  Examples of the (meth) acrylic monomer (y) capable of forming a homopolymer having a glass transition temperature higher than 15 ° C. include neopentyl acrylate (22 ° C.), cyclohexyl acrylate (19 ° C.), hexadecyl acrylate ( 35 ° C.), isobornyl acrylate (94 ° C.), phenyl acrylate (57 ° C.), acrylamide (165 ° C.), benzyl methacrylate (54 ° C.), methyl methacrylate (105 ° C.), ethyl methacrylate (65 ° C.), Propyl methacrylate (35 ° C), isopropyl methacrylate (81 ° C), butyl methacrylate (20 ° C), isobutyl methacrylate (53 ° C), sec-butyl methacrylate (60 ° C), t-butyl methacrylate (118 ° C) ), Cyclohexyl methacrylate (83 ° C.) 2-hydroxyethyl methacrylate (85 ° C.), isobornyl methacrylate (110 ° C.) (reproduced from Ter value from Polymer Handbook (4th ed.)), T-butyl acrylate (TBA; 41 ° C.) (represented by Osaka Organic Chemical Co., Ltd.) Manufactured, the Tg value is reprinted from the company's HP), 2-hydroxy-3-phenoxypropyl acrylate (M-600A; 17 ° C.) (the above is manufactured by Kyoeisha Chemical Co., Ltd., the Tg value is reprinted from the company's HP) (DMAA; 119 ° C), acryloylmorpholine (ACMO; 145 ° C), dimethylaminopropylacrylamide (DMAPAA; 134 ° C), isopropylacrylamide (NIPAM; 134 ° C), diethylacrylamide (DEAA; 81 ° C), hydroxyethylacrylamide (HEAA) ; 98 ° C) (above, Co., Ltd.) Manufactured by Kojin Co., Ltd., and Tg values are reprinted from the company's HP). These can be used alone or in combination of two or more. Among them, it is particularly preferable to use cyclohexyl acrylate, isobornyl acrylate, and acryloylmorpholine because both excellent adhesion and holding power can be achieved.

  Moreover, as said (meth) acrylic monomer (B) used in this invention, design Tg of the copolymer formed by them is designed in the range used as 15 degrees C or less, and the effect of this invention is impaired. If it is not within the range, other vinyl monomers may be used in addition to the above (x) and (y).

  The amount of the (meth) acrylic monomer (B) used is 30 to 200 from the viewpoint of achieving both excellent adhesive force 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).

  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, it is possible to achieve both excellent adhesive strength and holding power, and to prevent discoloration of the adhesive layer over time. With the specific (meth) acrylic monomer used in the present invention, From the viewpoint of improving compatibility and curability, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2 , 4,6-trimethylbenzoyl) -phenylphosphine oxide is preferably used.

  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.

  Further, when the pressure-sensitive adhesive comprising the resin composition for UV-curable pressure-sensitive adhesive of the present invention is used for an optical member, the UV-curable pressure-sensitive adhesive composition of the present invention further contains a light-resistant stabilizer (D). Is preferable from the viewpoint of improving light resistance stability.

  The light-resistant stabilizer (D) captures radicals generated by photodegradation, for example, radical scavengers such as thiol-based, thioether-based and hindered amine-based compounds, and ultraviolet light such as benzophenone-based and benzoate-based compounds. An absorbent etc. can be used and these may be used individually or in combination of 2 or more types. Among them, from the viewpoint of maintaining compatibility between excellent adhesive strength 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, it is possible to maintain both excellent adhesive strength and holding power, maintain heat and moisture resistance, and further improve compatibility with the specific (meth) acrylic monomer used in the present invention and light stability. From the viewpoint, it is particularly preferable to use a hindered amine compound having an amino ether group.

  The light-resistant stabilizer (D) is 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). 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.

  Further, when the pressure-sensitive adhesive comprising the resin composition for UV-curable pressure-sensitive adhesive of the present invention is used for an optical member, the UV-curable pressure-sensitive adhesive composition of the present invention further contains an antioxidant (E). It is preferable from the viewpoint of improving heat-resistant yellowing.

  The antioxidant (E) is a hindered phenolic compound (primary antioxidant) that captures radicals generated by thermal degradation, and a phosphorus-based or sulfur-based compound that decomposes peroxides generated by thermal degradation ( Secondary antioxidants) 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 maintain both excellent adhesive strength and holding power, maintain heat and heat resistance, and further improve compatibility with the specific (meth) acrylic monomer used in the present invention and heat yellowing resistance. From the viewpoint of possible, it is preferable to use a phosphorus compound, and triphenylphosphine, bis [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl phosphite, pentaerythritol tetrakis [3- ( Particular preference is given to using 3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

  The antioxidant (E) is 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). It is preferable from a viewpoint which can provide yellowing, and it is more preferable to use in the range of 0.1-5 mass parts.

  In addition, in the case where the pressure-sensitive adhesive comprising the resin composition for UV-curable pressure-sensitive adhesive of the present invention is used for the production of optical members, particularly touch panels, indium tin oxide (hereinafter abbreviated as ITO) which is a transparent conductive material. From the viewpoint of preventing metal corrosion (rust prevention), the ultraviolet curable pressure-sensitive adhesive composition of the present invention preferably further contains a rust prevention agent (F).

  Examples of the antirust agent (F) include triazole compounds, organic carboxylic acid amine salts, nitrite amine salts, phosphoric acid amine salts, amine carbonates, heterocyclic amines, and the like. Or you may use together. Compatibility with the specific (meth) acrylic monomer used in the present invention, maintaining both cohesion and excellent holding power, and maintaining moisture and heat resistance, and without impairing light stability and heat yellowing resistance. From the viewpoint of further improving rust prevention, 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.

  Commercially available products such as “IRGAMET (registered trademark) 30” and “IRGAMET (registered trademark) 38S” (above, manufactured by BASF Japan Ltd.) can be used as the triazole compound.

  The amount of the rust inhibitor (F) used is within a range of 0.001 to 5 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate resin (A) without reducing adhesive properties. From the viewpoint of imparting good rust prevention properties, it is more preferable to use in the range of 0.01 to 2 parts by mass.

  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 light-resistant stabilizer (D), an antioxidant (E), a rust inhibitor (F), or a part or all of the (meth) acrylic monomer (B) In the presence, a urethane (meth) acrylate resin (A) is produced, and a polymerization initiator (C) and, if necessary, a light-resistant stabilizer (D), an antioxidant (E), and a rust inhibitor (F) are mixed. It can manufacture by the method of.

  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 1000-10000 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 a thixotropic agent, a sensitizer, a polymerized gold material, a curing agent, a curing accelerator, a leveling agent, a tackifier, a wax, a thermal stabilizer, a fluorescent whitening agent, a 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 retardant, water absorbent, moisture absorbent, deodorant Agents, foam stabilizers, antifoaming agents, antifungal agents, antiseptics, algaeproofing agents, antiblocking agents, hydrolysis inhibitors, organic and inorganic water-soluble compounds, and the like can be used.

  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.

  Moreover, the resin composition for ultraviolet curable adhesives of this invention is the said urethane (meth) acrylate resin (A), the said (meth) acryl monomer (B), the said photoinitiator (C), and the said Other additives or the like may be dissolved or dispersed in a solvent such as an organic solvent or an aqueous medium, but the urethane (meth) acrylate resin (B) in the (meth) acrylic monomer (B) When A) or the photopolymerization initiator (C) is dissolved or dispersed, a step of removing the solvent contained in the pressure-sensitive adhesive is not required when the laminate is produced by bonding the substrates. It is preferable because the production efficiency of the laminate can be improved.

  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 composed of the ultraviolet curable pressure-sensitive adhesive resin composition of the present invention can be suitably used as a pressure-sensitive adhesive used for an optical member because it has both excellent adhesive strength and holding power. In particular, it can be suitably used for the production of touch panels, liquid crystal displays, plasma displays, organic EL displays and the like.

As a suitable use aspect of the pressure-sensitive adhesive comprising the resin composition for ultraviolet curable pressure-sensitive adhesive of the present invention, for example,
In the touch panel, a plastic substrate, a flexible printed substrate, a glass substrate, or a pressure-sensitive adhesive that bonds graphene, which is a transparent conductive material, or a substrate on which ITO is vapor-deposited to these substrates,
In a liquid crystal display, a pressure-sensitive adhesive that bonds a transparent base material made of glass or plastic and a polarizing plate constituting the outermost part of the liquid crystal panel,
In a liquid crystal display, a pressure-sensitive adhesive used for a gap called an air gap installed between a transparent protective substrate made of glass or plastic and a liquid crystal panel,
Etc.

  In the touch panel, the pressure-sensitive adhesive comprising the ultraviolet curable pressure-sensitive adhesive resin composition of the present invention is made of a plastic substrate, a flexible print substrate, a glass substrate, or graphene, which is a transparent conductive material, or ITO on these substrates. When used as a pressure-sensitive adhesive for bonding a vapor-deposited substrate or the like, at least a plastic layer is formed on both sides of the layer (i) formed using the pressure-sensitive adhesive made of the ultraviolet curable pressure-sensitive adhesive resin composition of the present invention. A layer (ii) composed of one type of substrate selected from the group consisting of a substrate, a flexible printed substrate, a glass substrate, and a substrate obtained by depositing ITO (indium tin oxide) on these substrates was laminated. Aspect is employed.

  Here, the layer (i) can be formed using a pressure-sensitive adhesive comprising the resin composition for ultraviolet curable pressure-sensitive adhesive of the present invention, and its thickness varies depending on the field of use of the touch panel, Due to the thinning of the liquid crystal display, the thickness is preferably about 10 to 500 μm, more preferably 50 to 500 μm.

  The layer (ii) is composed of one kind of substrate selected from the group consisting of a plastic substrate, a flexible printed substrate, a glass substrate, and a substrate obtained by depositing ITO on these substrates, and the layer (i) The same or different substrates can be used on both sides.

As said plastic base material, the base material and PC which consist of generally used acrylic resin etc.
(Polycarbonate), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), modified PPE (polyphenylene ether), PET (polyethylene terephthalate), COP (cycloolefin polymer), TAC (triacetyl cellulose), antireflection film or sheet, An antifouling film or sheet, a transparent conductive film film or sheet constituting the touch panel, or the like can be used.

The method for producing the laminate is selected from the group consisting of a plastic substrate, a flexible print substrate, a glass substrate, or a substrate obtained by depositing ITO on these substrates, for example, for forming the layer (ii). After applying the ultraviolet curable pressure-sensitive adhesive resin composition of the present invention to the surface of one type of substrate and performing the above-described irradiation of ultraviolet rays, another substrate is immediately placed on the coated surface, After being allowed to stand, the laminate of the present invention can be obtained. When the substrate is light transmissive, the ultraviolet curable adhesive resin composition of the present invention is applied to the surface of the substrate, and another substrate is placed on the coated surface. Later, by irradiating the above-mentioned ultraviolet rays from above the substrate,
The laminate of the present invention can be obtained.

  Moreover, when the resin composition for ultraviolet curable adhesives of this invention contains the said other additive, after performing the said ultraviolet irradiation if necessary, it is about 40-80 degreeC as needed. You may heat with.

  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, 456.4 parts by mass of polycarbonate polyol (“ETERRNACOLL UH-100, manufactured by Ube Industries, Ltd., hydroxyl value 112 mgKOH / g”), 2 -11.0 parts by mass of hydroxyethyl acrylate, 1.7 parts by mass of 2,6-ditertiarybutyl-cresol, and 0.3 parts by mass of p-methoxyphenol were added. After raising the temperature in the reaction vessel to 40 ° C., 100.0 parts by mass of isophorone diisocyanate was added. Therefore, 0.06 part by mass 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 acrylate resin as (A-1). The obtained urethane acrylate resin (A-1) had an acrylic group equivalent weight of 6000 and a weight average molecular weight of 17,000.

[Comparative 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, 164.3 parts by mass of polytetramethylene glycol (weight average molecular weight 1000), 28.6 parts by mass of 1,4-butanediol, 2- 4.9 parts by mass of hydroxyethyl acrylate, 1.7 parts by mass of 2,6-ditertiarybutyl-cresol, and 0.3 parts by mass of p-methoxyphenol were added. After raising the temperature in the reaction vessel to 40 ° C., 101.6 parts by mass of isophorone diisocyanate was added. Therefore, 0.06 part by mass of dioctyltin dineodecanate was added, and the temperature was raised to 80 ° C. over 1 hour. Then, it hold | maintained at 80 degreeC for 12 hours, and after confirming that all the isocyanate groups have lose | disappeared, it cooled and obtained urethane acrylate resin as (A-2). The obtained urethane acrylate resin (A-2) had an acrylic group equivalent weight of 7000 and a weight average molecular weight of 12,000.

[Example 1]
<Adjustment of resin composition for UV curable adhesive>
In a container equipped with a stirrer, a reflux condenser, and a thermometer, 100 parts by mass of the urethane (meth) acrylate resin (A-1) obtained in Synthesis Example 1, 65 parts by mass of butyl acrylate, and 45 parts by mass of cyclohexyl acrylate are contained in the container. The mixture was added at an internal temperature of 80 ° C. and stirred until uniform. Thereafter, the mixture was cooled to room temperature, and 3 parts by mass of 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-decanedioate were stirred with stirring. Piperidinyl) ester (“Tinuvin (registered trademark) 123”, manufactured by BASF Japan Ltd.) 1 part by mass, 1 part by mass of triphenylphosphine, and 1-bis (2-ethylhexyl) aminomethyl-1,2,4-triazole 0.1 parts by mass (“IRGAMET (registered trademark) 30”, manufactured by BASF Japan Ltd.) were sequentially added and stirred until uniform. Thereafter, the mixture was filtered through a 200 mesh wire mesh to obtain an ultraviolet curable adhesive resin composition.

[Examples 2 to 6, Comparative Example 1]
Except having changed the kind and usage-amount of the (meth) acryl monomer to be used as shown in Tables 1-2, the resin composition for ultraviolet curable adhesives was obtained similarly to Example 1. FIG.

[Comparative Example 2]
In a container equipped with a stirrer, a reflux condenser, and a thermometer, 100 parts by mass of the urethane (meth) acrylate resin (A-2) obtained in Comparative Synthesis Example 1, 45 parts by mass of butyl acrylate, and 45 parts by mass of cyclohexyl acrylate were added. The vessel was added at a temperature of 80 ° C. and stirred until uniform. Thereafter, the mixture was cooled to room temperature, and 3 parts by mass of 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-decanedioate were stirred with stirring. Piperidinyl) ester (“Tinuvin (registered trademark) 123”, manufactured by BASF Japan Ltd.) 1 part by mass, 1 part by mass of triphenylphosphine, and 1-bis (2-ethylhexyl) aminomethyl-1,2,4-triazole 0.1 parts by mass (“IRGAMET (registered trademark) 30”, manufactured by BASF Japan Ltd.) were sequentially added and stirred until uniform. Thereafter, the mixture was filtered through a 200 mesh wire mesh to obtain an ultraviolet curable adhesive resin composition.

[Method for measuring weight average molecular weight]
The important average molecular weights of the polytetramethylene glycol and the urethane (meth) acrylate resin used in Examples and / or Comparative Examples were measured as follows.
(Measurement equipment and conditions)
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%)
Measures the weight average molecular weight in terms of polystyrene (*).
* Polystyrene: TSK standard polystyrene manufactured by Tosoh Corporation

[Method for producing adhesive film]
For UV curable adhesives obtained in Examples and Comparative Examples so that the film thickness after UV irradiation is 175 μm on the surface of a 50 μm-thick polyethylene terephthalate film (release PET 50) whose surface has been subjected to mold release treatment A resin composition was applied, and another release PET 50 different from the above was bonded onto the coated surface.

Next, an adhesive film in which two release PET50s were laminated via an adhesive layer was produced by irradiating ultraviolet rays from above the release PET50 using a UV irradiation device. 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 .
In addition, since the adhesive film was not able to produce the resin composition for ultraviolet curable adhesives obtained by the comparative example 1, subsequent evaluation was not able to be performed.

[Measurement method of adhesive strength]
One release PET 50 constituting the pressure-sensitive adhesive film was peeled off, and 75 μm thick polyethylene terephthalate (PET 75) was bonded to the surface of the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet. What cut | judged the said adhesive sheet to the width | variety of 25 mm was used as the test piece used for the measurement of adhesive force.

  A sample obtained by peeling off the other release PET50 from the test piece was a SUS304 stainless steel plate (surface finish BA (cold rolling, bright heat treatment)), polycarbonate (PC) plate, PET plate (PET film ("Lumirror T60", Toray Co., Ltd.) and a glass plate (JIS R 3202) attached to the SUS304 stainless steel plate with a double-sided tape) under a 2 kg roll × 2 reciprocation in an atmosphere of 23 ° C. and 50% RH. Affixed to the kimono. One hour after pasting, the 180 ° peel strength was measured in an atmosphere of 23 ° C. and 50% RH to obtain adhesive strength.

[Method of measuring holding force]
A test piece prepared in the same manner as the test piece used in the method for measuring the adhesive strength was laminated on a mirror-finished stainless steel plate so that the adhesion area was 25 mm × 25 mm, and the atmosphere was 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 also after 24 hours, the holding time was made into 24 hours or more, the gap | deviation width from an initial sticking position was measured, and it described together.

[Measurement method of wet heat resistance]
One release PET 50 constituting the pressure-sensitive adhesive film obtained in [Method for producing pressure-sensitive adhesive film] is peeled off, and a pressure-sensitive adhesive sheet is prepared by bonding 75 μm thick polyethylene terephthalate (PET75) to the surface of the pressure-sensitive adhesive layer. did. What cut | judged the said adhesive sheet to the width | variety of 25 mm was used as the test piece used for a measurement of moisture-and-heat resistance.

Moreover, the adherend was a glass plate (JIS R 3202) and was attached to the adherend by 2 kg roll × 2 reciprocation. This was left in an atmosphere of 60 ° C. × 90% RH and 85 ° C. × 85% RH for 250 hours. Thereafter, the 180 ° peel strength was measured under an atmosphere of 23 ° C. × 50% RH, and the adhesive strength was obtained after wet heat.
The wet heat resistance was judged from the difference between the adhesive strength to the glass plate obtained by the above [Method of measuring adhesive strength] and the adhesive strength after wet heat.

[Example 7]
(Manufacture of laminates)
The resin composition for ultraviolet curable adhesives obtained in Example 1 was used in the same manner as in [Method for producing adhesive film] to obtain an adhesive film having a thickness of 175 μm. Thereafter, one release PET50 film was peeled off and bonded to a polycarbonate film.

  Thereafter, the other release PET film was peeled off and bonded to a glass plate to obtain a laminate.

Claims (11)

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 resin composition for an ultraviolet curable pressure-sensitive adhesive containing the photopolymerization initiator (C),
The polyol (a) is a polycarbonate polyol,
The (meth) acrylic monomer (B) is methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-methoxyethyl acrylate, 2-hydroxyethyl acrylate and 4-hydroxy acrylate. A group consisting of at least one (meth) acrylic monomer (x) capable of forming a homopolymer having a glass transition temperature of 15 ° C. or lower selected from the group consisting of butyl , cyclohexyl acrylate, isobornyl acrylate and acryloylmorpholine The (meth) acrylic monomer (x) is a combination of one or more (meth) acrylic monomers (y) capable of forming a homopolymer having a glass transition temperature higher than 15 ° C. And the (meth) acrylic monomer (y) has a mass ratio of (x) / (y) = 90/10 to 40/60 It is enclosed, and these (meth) acrylic monomer are those capable of forming a glass transition temperature of 15 ℃ or less of the copolymer,
The amount of the (meth) acrylic monomer (B) used is in the range of 30 to 200 parts by mass with respect to 100 parts by mass of the urethane (meth) acrylate resin (A). Resin composition for pressure-sensitive adhesives. The resin composition for ultraviolet curable adhesives of Claim 1 whose weight average molecular weights of the said urethane (meth) acrylate resin (A) are 5000-50000. The photopolymerization initiator (C) is 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,4). The resin composition for an ultraviolet curable pressure-sensitive adhesive according to claim 1 or 2 , which is at least one selected from the group consisting of 6-trimethylbenzoyl) -phenylphosphine oxide. Furthermore, the resin composition for ultraviolet curable adhesives of any one of Claims 1-3 which contains a light-resistant stabilizer (D). Furthermore, the resin composition for ultraviolet curable adhesives of any one of Claims 1-4 which contains antioxidant (E). Furthermore, the resin composition for ultraviolet curable adhesives of any one of Claims 1-5 which contains a rust preventive agent (F). The resin composition for ultraviolet curable adhesives of Claim 4 whose said light-resistant stabilizer (D) is a hindered amine type compound. The resin composition for ultraviolet curable adhesives of Claim 5 whose said antioxidant (E) is a phosphorus compound. The resin composition for ultraviolet curable adhesives of Claim 6 whose said rust preventive agent (F) is a triazole type compound. Adhesive made of an ultraviolet-curable pressure-sensitive adhesive resin composition according to any one of claims 1-9. And is used in the optical member, according to claim 1 0, wherein the pressure-sensitive adhesive.