JP2008169319A - Curable resin composition for adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable resin composition for adhesives which can provide a good coating surface without adjusting its viscosity using an organic solvent, can temporarily adhere to an adherend by ultraviolet irradiation for adhesion, is capable of positioning and release of adherends, then shows increased adhesiveness at an ordinary temperature or by heating, and finally strongly adheres to the adherends. <P>SOLUTION: The curable resin composition for adhesives comprises a hydroxy group-containing urethane (meth)acrylate (A) prepared by reacting a diol compound (a1) having a molecular weight of 1,000-7,000, a polyisocyanate compound (a2), and a hydroxy group-containing (meth)acrylate compound (a3), a monomer having an ethylenically unsaturated double bond (B), a polyisocyanate compound (C), and a photoinitiator (D). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a curable resin composition for adhesives useful in the fields of building materials, packaging materials, printing materials, display materials, electrical and electronic component materials, optical devices, displays, and the like. It has particularly excellent adhesion to plates and films made of materials such as acrylic resin, polyester resin, triacetyl cellulose, and a good coated surface can be obtained without intentionally mixing an organic solvent in the composition. At the time of bonding, it can be temporarily bonded to the adherends by irradiation of active energy rays such as ultraviolet rays, and the adherends can be positioned and peeled off. The present invention relates to a curable resin composition for an adhesive that adheres firmly.

  Conventionally, curable adhesives applying heat curing and active energy ray curing have been widely used in various fields, and their fields of use are also increasing in recent years.

  And in the growing trend of the application field, for the purpose of improving the productivity of the manufacturing process, when adhering the adherends, the temporary adhesion state is taken in a short time and the adherends are positioned and peeled off as necessary. There is a demand for an adhesive having a performance capable of being used, and pressure sensitive adhesives are used in such fields. Pressure-sensitive adhesives are generally used by controlling the adhesive force by the balance between adhesive force and cohesive force and setting the adhesive force within the range that can be used in both the temporary and final adhesive states. Has been. However, there is a problem that it is difficult to produce an extremely high adhesive force because there is a limit to the adhesive force that can achieve both of these states. In addition, in order to show high adhesive strength and cohesive strength, the material used must have a high molecular weight, so there is a drawback that the viscosity of the composition itself becomes very high. However, since it was necessary to dilute to a suitable viscosity with a solvent and volatilize an unnecessary solvent after coating, it was not a highly productive method and had a problem of high environmental load.

  For these problems, as a pressure-sensitive adhesive that is excellent in adhesiveness, can temporarily adhere to adherends, and can be peeled off as necessary, for example, an ethylenically unsaturated group-containing acrylic resin, Disclosed is a curable resin composition containing a urethane (meth) acrylate oligomer obtained by reacting a polyol containing a (meth) acrylic polyol, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate, a photopolymerization initiator, and a crosslinking agent. (For example, refer to Patent Document 1). However, in the curable resin composition, the adhesive strength at the time of temporary adhesion is the same as the final adhesive strength. For example, in Example 1 of Patent Document 1, in the 180 ° peel test, the adhesive strength before ultraviolet curing (temporary adhesive strength). ) And UV-cured adhesive strength (final adhesive strength) are both only about 20 N / 25 mm. Therefore, the design of the curable resin composition must be performed by focusing on only one of the temporary adhesive force and the final adhesive force. As a result, it is difficult to reinforce the final adhesion between the adherends when trying to obtain a pressure-sensitive adhesive that can be easily peeled off between temporarily attached adherends. When trying to obtain a pressure-sensitive adhesive having a strong adhesive force, there is a problem that it is difficult to facilitate separation of temporarily bonded adherends.

  By the way, there is a paint field as a similar field of adhesives. Examples of UV curable coating compositions in this coating field include: a) urethane- (meth) acrylates containing (meth) acryloyl groups and free isocyanate groups, b) polyisocyanates other than a) and c) free A coating composition containing an ultraviolet initiator that initiates group polymerization and d) a compound containing an isocyanate-reactive group is disclosed (for example, see Patent Document 2). However, the coating composition can be UV-cured quickly so that the coated substrate can be handled, the properties can be adjusted according to the intended use, and sufficient curing can be obtained even in non-irradiated areas and poorly irradiated areas. It is disclosed as a purpose, and cannot be used as a pressure-sensitive adhesive that is “excellent in adhesion, can adhere temporarily to adherends, and can be peeled off if necessary”.

JP 2005-239856 A JP 11-263939 A

  The problem to be solved by the present invention is that when adhering, it is possible to temporarily adhere to adherends by irradiation of active energy rays such as ultraviolet rays, the adherends can be positioned and peeled off, and then heated at room temperature or afterwards. It is an object of the present invention to provide a curable resin composition for an adhesive that increases adhesion and finally adheres firmly to adherends.

  As a result of intensive studies to solve the above problems, the present inventors used a monomer having an ethylenically unsaturated double bond in place of the ethylenically unsaturated group-containing acrylic resin in Patent Document 1, By using a hydroxyl group-containing urethane (meth) acrylate obtained by using a diol compound having a molecular weight of 1,000 to 7,000 and a polyisocyanate compound, it is temporarily adhered to an adherend by irradiation of active energy rays such as ultraviolet rays. It is possible to position and peel off adherends, and at the same time, it is possible to obtain an adhesive force higher than the temporary adhesive force by heating at room temperature or heating, and finally adhere firmly to the adherends. The headline and the present invention were completed.

  That is, the present invention relates to a hydroxyl group-containing urethane obtained by reacting a diol compound (a1) having a molecular weight of 1,000 to 7,000, a polyisocyanate compound (a2) and a hydroxyl group-containing (meth) acrylate compound (a3) ( A curable adhesive for adhesives comprising a (meth) acrylate (A), a monomer (B) having an ethylenically unsaturated double bond, a polyisocyanate compound (C), and a photopolymerization initiator (D). A resin composition is provided.

  The curable resin composition for an adhesive of the present invention is applied to an adherend, and then irradiated with an active energy ray to be cured, thereby maintaining a certain degree of adhesive force, and removing the adherend and position of the adherend when necessary. It will be in the state of what is called temporary adhesion in which fine adjustment is possible. Further, the curing due to the reaction between the hydroxyl group and the isocyanate group in the composition gradually proceeds. For example, the strong adhesive force required finally can be obtained by holding at room temperature for 3 to 7 days.

  The hydroxyl group-containing urethane (meth) acrylate (A) used in the present invention comprises a diol compound (a1) having a molecular weight of 1,000 to 7,000, a polyisocyanate compound (a2), and a hydroxyl group-containing (meth) acrylate compound (a3). It is obtained by reacting. Here, when a diol having a molecular weight smaller than 1,000 is used as the diol compound (a1), the curing shrinkage of the final cured product becomes too large, so that a curable resin composition for an adhesive having insufficient adhesive force is obtained. Is not preferable. In addition, if a diol having a molecular weight larger than 7,000 is used as the diol compound (a1), the viscosity of the resin composition becomes too high, so that the curable resin composition for an adhesive that is poor in handling is not preferable. The molecular weight of the diol compound (a1) is particularly preferably 1,000 to 5,000 because the balance between the temporary adhesive force and the final adhesive force is good.

  Examples of the diol compound (a1) having a molecular weight of 1,000 to 7,000 include a polyester diol having a molecular weight of 1,000 to 7,000, a polyether diol having a molecular weight of 1,000 to 7,000, and a molecular weight of Examples thereof include polycarbonate diol having a molecular weight of 1,000 to 7,000, polycaprolactone diol having a molecular weight of 1,000 to 7,000, and the like.

  Examples of the polyester diol having a molecular weight of 1,000 to 7,000 include those obtained by reacting a dihydric alcohol with a dibasic acid. Examples of the dihydric alcohol include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, tripropylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4 -Cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol and the like. Examples of the dibasic acid include phthalic acid, isophthalic acid, terephthalic acid, succinic acid, maleic acid, fumaric acid, adipic acid, sebacic acid and the like.

  Examples of the polyether diol having a molecular weight of 1,000 to 7,000 include bisphenol A ethylene oxide addition diol, bisphenol A propylene oxide addition diol, bisphenol A butylene oxide addition diol, bisphenol F ethylene oxide addition diol, and bisphenol. Aromatic polyether diols such as propylene oxide addition diol of F, butylene oxide addition diol of bisphenol F, alkylene oxide addition diol of hydroquinone; polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,2-polybutylene glycol, poly Isobutylene glycol, copolymerized diol of propylene oxide and tetrahydrofuran, ethylene oxide and tetra Aliphatic polyether diols such as copolymer diols of drofuran, copolymer diols of ethylene oxide and propylene oxide, copolymer diols of tetrahydrofuran and 3-methyltetrahydrofuran, copolymer diols of ethylene oxide and 1,2-butylene oxide; hydrogenated Ethylene oxide addition diol of bisphenol A, propylene oxide addition diol of hydrogenated bisphenol A, butylene oxide addition diol of hydrogenated bisphenol A, ethylene oxide addition diol of hydrogenated bisphenol F, propylene oxide addition diol of hydrogenated bisphenol F, hydrogenated bisphenol F And cycloaliphatic polyether diols such as butylene oxide addition diols.

  Examples of the polycarbonate diol having a molecular weight of 1,000 to 7,000 include 1,6-hexanediol polycarbonate diol, 1,5-pentanediol polycarbonate diol, 1,4-butanediol polycarbonate diol, 1, Examples thereof include a copolymer polycarbonate diol of 6-hexanediol and 1,5-pentanediol, a copolymer polycarbonate diol of 1,6-hexanediol and 1,4-butanediol, and the like.

  Examples of the polycaprolactone diol having a molecular weight of 1,000 to 7,000 include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,2-polybutylene glycol, 1, Examples thereof include polycaprolactone diols obtained by reacting diols such as 6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,4-butanediol and ε-caprolactone.

  Furthermore, a hydroxyl group-containing acrylic resin, a hydroxyl group-terminated polybutadiene, a hydroxyl group-terminated hydrogenated polybutadiene, a hydroxyl group-terminated polydimethylsiloxane and the like can be used as the diol compound (a1) if the molecular weight is 1,000 to 7,000. Moreover, a diol compound (a1) may be used independently and may use 2 or more types together.

  In the present invention, “molecular weight” refers to the number average molecular weight in a polymer compound.

  The diol compound (a1) used in the present invention is preferably a polyester diol because a curable resin composition for an adhesive having a strong final adhesive strength can be obtained. Among polyester diols, polyester diols obtained by using 3-methyl-1,5-pentanediol as a polyhydric alcohol are particularly preferable.

  Examples of the polyisocyanate compound (a2) used in the present invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5. -Naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4 ' -Biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), 2,2,4-trimethylhexamethylene diisocyanate, 1 4-hexamethylene diisocyanate, bis (2-isocyanatoethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diene Examples thereof include aromatic diisocyanate compounds such as isocyanate and norbornane diisocyanate, aliphatic diisocyanate compounds, and cycloaliphatic diisocyanate compounds. Also included are compounds having 3 or more isocyanate groups, and compounds obtained by trimerizing the above-mentioned aromatic, aliphatic, and cycloaliphatic diisocyanate compounds. The polyisocyanate compound (a2) may be used alone or in combination of two or more.

  As the polyisocyanate compound (a2), those having different reactivities of a plurality of isocyanate groups contained in the molecule are preferable because they are unlikely to remain as unreacted polyisocyanate compounds. More preferred are range isocyanate and isophorone diisocyanate.

  When the curable resin composition for an adhesive of the present invention is used as a member requiring light resistance, the polyisocyanate compound (a2) may be an aliphatic polyisocyanate or a cyclic aliphatic polyisocyanate. Of these, isophorone diisocyanate is more preferable.

  Examples of the hydroxyl group-containing (meth) acrylate compound (a3) used in the present invention include compounds having at least one hydroxyl group and one or more (meth) acryloyl groups. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 1,4-butanediol mono (Meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, neopentyl glycol mono (meth) acrylate, lactone-modified hydroxyethyl ( Compounds represented by the following general formula (1) such as (meth) acrylate and polyether-modified hydroxyethyl (meth) acrylate

（Ｒ１は、水素原子またはメチル基を示し、Ｒ２及びＲ３はそれぞれ独立して、置換基を有していても良く分岐していても良い炭素原子数２〜８のアルキレン鎖を示し、ｍおよびｎはそれぞれ独立して０〜１０の整数である。ただし同時に０はとらない。）等が挙げられる。また、トリメチロールプロパンジ（メタ）アクリレート、トリメチロールエタンジ（メタ）アクリレート、ペンタエリスリトールトリ（メタ）アクリレート、ジペンタエリスリトールペンタ（メタ）アクリレート等も挙げられる。さらにアルキルグリシジルエーテル、アリルグリシジルエーテル、グリシジル（メタ）アクリレート等のグリシジル基含有化合物と（メタ）アクリル酸との付加反応により得られる化合物も挙げられる。

(R1 represents a hydrogen atom or a methyl group, R2 and R3 each independently represents an alkylene chain having 2 to 8 carbon atoms which may have a substituent or may be branched; n is each independently an integer of 0 to 10. However, 0 is not taken at the same time. Further, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate and the like can also be mentioned. Furthermore, the compound obtained by addition reaction of glycidyl group containing compounds, such as alkyl glycidyl ether, allyl glycidyl ether, and glycidyl (meth) acrylate, and (meth) acrylic acid is also mentioned.

  As the above-mentioned hydroxyl group-containing (meth) acrylate compound (a3), a (meth) acrylate compound containing one ethylenically unsaturated double bond and one hydroxyl group in the molecule is excellent in adhesive strength. A curable resin composition is preferable because 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and lactone-modified hydroxyethyl (meth) acrylate are particularly preferable.

  The hydroxyl group-containing urethane (meth) acrylate (A) used in the present invention is obtained by, for example, converting the diol compound (a1), the polyisocyanate compound (a2), and the hydroxyl group-containing (meth) acrylate compound (a3) to urethane (meth) acrylate. The diol compound (a1) and / or the hydroxyl group-containing (meth) acrylate compound (a3) can be obtained by reacting them in such a quantitative ratio that the hydroxyl group remains therein. Here, as the hydroxyl group-containing urethane (meth) acrylate (A), a urethane (meth) acrylate having a hydroxyl value of 7.0 to 42.0 mgKOH / g has sufficient adhesive strength after irradiation with active energy rays as temporary adhesive strength. And since the last adhesive force after reaction completion becomes strong, 10.0-42.0 mgKOH / g is more preferable.

  The urethane (meth) acrylate (A) used in the present invention comprises an isocyanate group in the polyisocyanate compound (a2), a hydroxyl group in the diol compound (a1), and a hydroxyl group in the hydroxyl group-containing (meth) acrylate compound (a3). It is synthesized by reacting. As the order of the reaction at this time, for example, the diol compound (a1), the polyisocyanate compound (a2) and the hydroxyl group-containing (meth) acrylate compound (a3) may be charged and reacted together, or the diol compound (a1) And the hydroxyl group-containing (meth) acrylate compound (a3) may be reacted after reacting the polyisocyanate compound (a2), and further the polyisocyanate compound (a2) and the hydroxyl group-containing (meth) acrylate compound (a3) may be reacted. The diol compound (a1) may be reacted after the reaction.

  As a reaction ratio at the time of making a diol compound (a1), a polyisocyanate compound (a2), and a hydroxyl-containing (meth) acrylate compound (a3) react, a diol compound (a1) and a hydroxyl-containing (meth) acrylate compound ( The reaction ratio is such that the isocyanate groups in the polyisocyanate compound (a2) are reduced with respect to 1 equivalent of the total hydroxyl groups in a3). Among them, the hydroxyl value in the hydroxyl group-containing urethane (meth) acrylate (A) used in the present invention is preferably 7.0 to 42.0 mgKOH / g, more preferably 10.0 to 42.0 mgKOH / g. When the reaction is performed at a ratio, the adhesive force after irradiation with active energy rays is sufficient as a temporary adhesive force, and the final adhesive force after the reaction is also strong.

  In the present invention, the hydroxyl value of the urethane (meth) acrylate (A) is, for example, the hydroxyl group contained in the urethane (meth) acrylate (A) of the present invention in an appropriate organic solvent, for example, pyridine. The acetic acid produced when reacted with acetic anhydride in the solution can be quantified by titrating with potassium hydroxide using phenolphthalein as an indicator.

  The reaction temperature for reacting the diol compound (a1), the polyisocyanate compound (a2) and the hydroxyl group-containing (meth) acrylate compound (a3) is usually obtained by reacting at a reaction temperature of 60 to 100 ° C.

  In this case, a known and usual urethane catalyst may be used. Examples of the urethanization catalyst include tin compounds such as di-n-butyltin dilaurate, di-n-butyltin diacetate and tin octylate, triethylamine, 1,4-diazabicyclo [2.2.2] octane, 2,6, 7-trimethyl-1,4-diazabicyclo [2.2.2] octane, zinc compounds such as zinc octylate and zinc naphthenate, urethanization catalysts such as zirconium tetraacetylacetonate, copper naphthenate and cobalt naphthenate, It is preferable to use 0.01 to 1% by weight based on the total weight of the diol compound (a1), the polyisocyanate compound (a2) and the hydroxyl group-containing (meth) acrylate compound (a3).

  The number average molecular weight of the urethane (meth) acrylate (A) used in the present invention is 1,500 to 10,000, even if the viscosity of the resulting curable resin composition for adhesives does not use an organic solvent. It is preferable because the viscosity becomes optimum when applied, the temporary adhesive force after irradiation with active energy rays is good, and the resin composition hardly remains on the adherend surface during re-peeling. The number average molecular weight of the urethane (meth) acrylate (A) of the present invention is particularly preferably 1,500 to 8,000.

  The content of urethane (meth) acrylate (A) in the curable resin composition for adhesives of the present invention is excellent in composition coating properties such as viscosity, adhesive properties at the time of temporary adhesion and final adhesion, etc. Since the point is also good, the content of urethane (meth) acrylate (A) is urethane (meth) acrylate (A), compound (B) having an ethylenically unsaturated double bond, polyisocyanate compound (C) and 10-80 weight% is preferable with respect to the total weight of a photoinitiator (D), and 20-70 weight% is further more preferable.

  Examples of the monomer (B) having an ethylenically unsaturated double bond used in the present invention include those having one or more ethylenically unsaturated double bonds.

  Examples of the monomer having one ethylenically unsaturated double bond include, for example, a monofunctional (meth) acrylate having a cyclic structure, a (meth) acrylic acid ester having an alkyl group having 1 to 22 carbon atoms, and a hydroxyalkyl group. (Meth) acrylic acid ester having lactone, modified lactone-modified hydroxyethyl (meth) acrylate, (meth) acrylate having polyalkylene glycol group, phosphoethyl (meth) acrylate, N, N-dialkylaminoalkyl (meth) acrylate, etc. Is mentioned.

  Examples of the monomer having two ethylenically unsaturated double bonds include di (meth) acrylate of ethylene oxide modified bisphenol A, di (meth) acrylate of propylene oxide modified bisphenol A, and ethylene oxide / propylene oxide modified bisphenol A. Di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (Meth) acrylate, di (meth) acrylate of polypropylene glycol, 1,3-butylene glycol di (meth) acrylate, 1,4-butylene glycol di ( Acrylate), 1,6-hexamethylene glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, Examples thereof include compounds in which (meth) acrylic acid such as di (meth) acrylate or neopentylglycol adipate di (meth) acrylate, which is obtained by adding caprolactone to neopentyl glycol hydroxypivalate, is a bimolecular ester bond.

  The monomer having two ethylenically unsaturated double bonds includes compounds having two hydroxyl groups, such as ethylene oxide adducts of halogenated bisphenol A, propylene oxide adducts of halogenated bisphenol A, and bisphenol F. Ethylene oxide adduct, propylene oxide adduct of bisphenol F, ethylene oxide adduct of halogenated bisphenol F, propylene oxide adduct of halogenated bisphenol F, ethylene oxide adduct of bisphenol S, propylene oxide adduct of bisphenol S, halogenated bisphenol S (Meth) acrylic acid is added to compounds having two hydroxyl groups, such as ethylene oxide adducts, propylene oxide adducts of halogenated bisphenol S, and tricyclodecane dimethylol. Difunctional (meth) acrylates such as compounds ester-linked and the like are also mentioned.

  Examples of monomers having 3 or more ethylenically unsaturated double bonds include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, glycerin tri (meth) acrylate, and tri (acryloyloxyethyl). Polyfunctional (meth) acrylates such as isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tri [(meth) acryloyloxyethoxy] phosphate It is done.

  Further, for example, vinyl compounds having an aromatic ring structure or a heterocyclic structure such as styrene, α-methylstyrene, N-vinylpyrrolidone, N-vinylcaprolactone, acryloylmorpholine, dimethylacrylamide, diethylacrylamide, diisopropylacrylamide, etc. are also ethylenic. Examples thereof include a monomer (B) having an unsaturated double bond.

  The monomer (B) having an ethylenically unsaturated double bond used in the present invention has a high adhesive force and exhibits a viscosity reducing effect, so that a low viscosity curable resin composition for an adhesive can be obtained. To monofunctional (meth) acrylates having a cyclic structure.

  Examples of the monofunctional (meth) acrylate having the cyclic structure include benzoyloxyethyl (meth) acrylate, benzyl (meth) acrylate, phenylethyl (meth) acrylate, phenoxyethyl (meth) acrylate, and phenoxydiethylene glycol (meth) acrylate. 2-hydroxy-3-phenoxypropyl (meth) acrylate; the following general formula (2)

（式中、Ｒ５は炭素原子数１〜５の炭化水素基、Ｒ６は水素原子またはメチル基を表し、ｎは平均値で０〜３である。）
で表される２−フェニル−２−（４−（メタ）アクリロイルオキシフェニル）プロパン、２−フェニル−２−（４−（メタ）アクリロイルオキシエトキシフェニル）プロパン、２−フェニル−２−（４−（メタ）アクリロイルオキシプロポキシフェニル）プロパン；

(In the formula, R5 represents a hydrocarbon group having 1 to 5 carbon atoms, R6 represents a hydrogen atom or a methyl group, and n is an average value of 0 to 3).
2-phenyl-2- (4- (meth) acryloyloxyphenyl) propane, 2-phenyl-2- (4- (meth) acryloyloxyethoxyphenyl) propane, 2-phenyl-2- (4- (Meth) acryloyloxypropoxyphenyl) propane;

Chlorophenyl (meth) acrylate, bromophenyl (meth) acrylate, chlorobenzyl (meth) acrylate, bromobenzyl (meth) acrylate, chlorophenylethyl (meth) acrylate, bromophenylethyl (meth) acrylate, chlorophenoxyethyl (meth) acrylate, Bromophenoxyethyl (meth) acrylate, 2,4,6-trichlorophenyl (meth) acrylate, 2,4,6-tribromophenyl (meth) acrylate, 2,4,6-trichlorobenzyl (meth) acrylate, 2, 4,6-tribromobenzyl (meth) acrylate, 2,4,6-trichlorophenoxyethyl (meth) acrylate, 2,4,6-tribromophenoxyethyl (meth) acrylate, o-phenylphenol (poly) ethoxy Meth) acrylate, p- phenylphenol (poly) a monofunctional (meth) acrylic acid esters having an aromatic ring such as ethoxy (meth) acrylate;

Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl cyclocarbonate (meth) acrylate, and other alicyclic rings and heterocycles Examples include (meth) acrylic acid esters having a ring structure.

  Among the monofunctional (meth) acrylates having the cyclic structure, phenoxyethyl (meth) acrylate and / or isoboronyl (meth) acrylate is preferable, and a combination of phenoxyethyl acrylate and isobornyl acrylate is more preferable. Moreover, the monomer (B) which has an ethylenically unsaturated double bond may be individual, or may use 2 or more types together.

  The content of the monomer (B) having an ethylenically unsaturated double bond is such that viscosity is applied to the composition without affecting the plastic substrate due to dissolution and erosion, temporary adhesion, and final adhesion. In order to maintain the adhesive properties at the time, the content of the monomer (B) having an ethylenically unsaturated double bond is the urethane (meth) acrylate (A), a single amount having an ethylenically unsaturated double bond The content is preferably 20 to 90% by weight, more preferably 30 to 80% by weight, based on the total weight of the body (B), polyisocyanate compound (C) and photopolymerization initiator (D).

  As a polyisocyanate compound (C) used by this invention, the compound quoted as the said polyisocyanate compound (a2) can be used, for example. Here, the polyisocyanate compound (C) may be the same as or different from the polyisocyanate compound (a2). The polyisocyanate compound (C) may be used alone or in combination of two or more. In particular, a polyisocyanate compound having 3 or more isocyanate groups is preferable in order to develop an excellent final adhesive force.

  As a typical example of a polyisocyanate compound having three or more isocyanate groups, for example, triphenylmethane as described in “Polyurethane resin handbook (edited by Keiji Iwata, Nikkan Kogyo Shimbun)” Triisocyanate, tris (isocyanatephenyl) thiophosphate, lysine ester triisocyanate, 2-isocyanate ethyl-2,6-diisocyanate caproate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyl Examples include octane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, and tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hydrogenated 4,4 '. Diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, transcyclohexane 1,4-diisocyanate, lysine diisocyanate, tetremethylxylene diisocyanate And trimerized aromatic, aliphatic and cycloaliphatic diisocyanate compounds such as trimethylhexamethylene diisocyanate, such as diisocyanate burette type and isocyanurate type polyisocyanate. In addition, among polyisocyanate compounds having a phenyl isocyanate skeleton called polymeric MDI composed of a polynuclear mixture having several structures, compounds containing three or more functional groups of isocyanate groups can also be used.

  Furthermore, a compound having three or more isocyanate groups in a molecule obtained by reacting the isocyanate-containing compound as described above with a compound having two or more active hydrogen atoms such as an amino group, a hydroxyl group and a carboxyl group can also be used.

  Among these polyisocyanate compounds having three or more isocyanate groups, a trimer of an aliphatic diisocyanate and / or a cycloaliphatic diisocyanate compound from the viewpoint of excellent durability at the time of temporary adhesion by active energy rays or after final adhesion. The polyisocyanate compound is most preferably a polyisocyanate compound obtained by trimerizing hexamethylene diisocyanate (isocyanurate type polyisocyanate of hexamethylene diisocyanate).

  As the content of the polyisocyanate compound (C) that can be used in the present invention, the pot life of the adhesive curable resin composition of the present invention is maintained, and the difference between the temporary adhesive force and the final adhesive force is appropriately controlled. Therefore, 0.5% of the total weight of the urethane (meth) acrylate (A), the compound (B) having an ethylenically unsaturated double bond, the polyisocyanate compound (C) and the photopolymerization initiator (D). It is preferably ˜15% by weight, and more preferably in the range of 1.0 to 8% by weight.

  Examples of the photopolymerization initiator (D) used in the present invention include benzophenone, 3,3′-dimethyl-4-methoxybenzophenone, 4,4′-bisdimethylaminobenzophenone, 4,4′-bisdiethylaminobenzophenone, 4 Benzophenones, such as 4,4'-dichlorobenzophenone, Michler's ketone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone;

Xanthones such as xanthone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, or thioxanthones;

Acyloin ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; α-diketones such as benzyl and diacetyl;

Examples thereof include sulfides such as tetramethylthiuram disulfide and p-tolyl disulfide; benzoic acids such as 4-dimethylaminobenzoic acid and ethyl 4-dimethylaminobenzoate.

  Photopolymerization initiators other than those described above, such as 3,3′-carbonyl-bis (7-diethylamino) coumarin, 1-hydroxycyclohexyl phenyl ketone, 2,2′-dimethoxy-1,2-diphenylethane-1 -One, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane- 1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 1- (4-isopropyl (Lopylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 4-benzoyl-4'-methyldimethylsulfide, 2 , 2'-diethoxyacetophenone, benzyldimethylketal, benzyl-β-methoxyethyl acetal, methyl o-benzoylbenzoate, bis (4-dimethylaminophenyl) ketone, p-dimethylaminoacetophenone, α, α- Dichloro-4-phenoxyacetophenone, pentyl-4-dimethylaminobenzoate, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, 2,4-bis-trichloromethyl-6- [di- (ethoxycarbonyl) Methyl) amino] phenyl-S-triazine, 2,4-bis Trichloromethyl-6- (4-ethoxy) phenyl-S-triazine, 2,4-bis-trichloromethyl-6- (3-bromo-4-ethoxy) phenyl-S-triazine anthraquinone, 2-t-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, and the like can also be used as the photopolymerization initiator (C).

  Examples of the photopolymerization initiator (D) include Irgacure-184, 149, 261, 369, 500, 651, 784, 819, 907, 1116, 1664, 1700, 1750. 1800, 1850, 2959, 4043, Darocur-1173 (Ciba Specialty Chemicals), Lucirin TPO (BASF), KAYACURE-DETX, MBP, DMBI, EPA, OA [Japan Kaicaku Co., Ltd.], VISURE-10, 55 (STAUFFER Co. LTD), TRIGONALP1 (AKZO Co. LTD), SANDORY 1000 (SANDOZ Co. LTD), DEAP (APJOHN Co. LTD), QUANTACURE-PDO, ITX, It can also be used PD (manufactured by WARD BLEKINSOP Co.LTD) such commercial products.

  As the photopolymerization initiator (D), 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy -2-methyl-1-propan-1-one, thioxanthone and thioxanthone derivatives, 2,2′-dimethoxy-1,2-diphenylethane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis ( 2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1- (4- One or more mixed systems selected from the group of morpholinophenyl) -butan-1-one , High particularly preferred curable upon temporary adhesive.

  Moreover, a photoinitiator (D) may be used independently and may use 2 or more types together.

  Incidentally, an article using the curable resin composition for an adhesive of the present invention may require transparency up to the near ultraviolet region. Moreover, in manufacture of the articles | goods using the curable resin composition for adhesives of this invention, active energy rays, such as an ultraviolet-ray, may be irradiated through the transparent plastic base material used as a to-be-adhered body. In those cases, a high polymerization reaction initiation efficiency can be exhibited with a low concentration of the photopolymerization initiator in order to suppress a decrease in transmittance in the near ultraviolet region caused by absorption of the photopolymerization initiator in the cured product. The photopolymerization initiator (D) that can be used, for example, can effectively cause a curing reaction by a relatively long wavelength active energy ray that reaches through the plastic substrate, also absorbs light in the long wavelength region of 360 to 450 nm. Initiators having the ability are preferable, among them, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2 1,4,4-trimethylpentylphosphine oxide or other phosphine oxide compounds alone or other The combination of the agent is particularly preferred.

  In the present invention, various photosensitizers can be used in combination with the photopolymerization initiator (D). Typical examples of the photosensitizer used in the present invention include amines, ureas, sulfur-containing compounds, phosphorus-containing compounds, chlorine-containing compounds, nitriles, and other nitrogen-containing compounds.

  The amount of the photopolymerization initiator (D) used is not particularly limited, but the sensitivity is good, and it is difficult to cause precipitation of crystals and physical properties of the coating film. Therefore, it is preferable to use ethylenically unsaturated double in the composition. It is used in an amount of 0.05 to 20% by weight, more preferably 0.1 to 10% by weight, based on the compound (B) having a bond.

  Further, if necessary, a curing catalyst may be added to the curable resin composition for an adhesive of the present invention in order to accelerate the reaction of isocyanate groups in the system with hydroxyl groups in the system. good. In particular, it is preferable to use a curing catalyst because it takes a long time to move to the final adhesion state by leaving it at room temperature. Examples of the curing catalyst include known and commonly used urethanization catalysts such as tin compounds such as di-n-butyltin dilaurate, di-n-butyltin diacetate and tin octylate, triethylamine, 1,4-diazabicyclo [2.2. .2] Octane, 2,6,7-trimethyl-1,4-diazabicyclo [2.2.2] octane, zinc compounds such as zinc octylate, zinc naphthenate, zirconium tetraacetylacetonate, copper naphthenate, naphthene Cobalt acid or the like can be used.

  In this case, in order for the curing catalyst to maintain the pot life of the curable resin composition for adhesives of the present invention, the content of the photopolymerization initiator (D) is such urethane (meth) acrylate (A), ethylenic. 0.001-0.1 weight% is preferable with respect to the total weight of the compound (B) which has an unsaturated double bond, a polyisocyanate compound (C), and a photoinitiator (D), and 0.005-0. More preferably, it is blended in the range of 05% by weight.

  Further, if necessary, in the curable resin composition for adhesives of the present invention, various additives such as an ultraviolet absorber, a light stabilizer, and an antioxidant can be used to improve the coating film and improve the paintability. It is also possible to add a rheology control agent, a silicon additive, a defoaming agent and the like.

  The viscosity of the curable resin composition for adhesives of the present invention is desirably in the range of 100 to 20000 mPa · s at 25 ° C., preferably 200 to 15000 mPa · s, for uniform application to the adherend. s. However, even if it is in a range other than the above, it will not be trapped in the above viscosity range if a method such as adjusting the viscosity by controlling the temperature of the adhesive curable resin composition is taken.

  When the adherends are bonded to each other using the curable resin composition for an adhesive of the present invention, a temporary adhesion state is obtained by irradiating active energy rays. In the temporarily bonded state, the adherend can be peeled off. When left in such a temporarily bonded state, for example, at room temperature, a crosslinked structure is gradually formed. Specifically, as this crosslinked structure, for example, a crosslinked structure by a urethane bond between a hydroxyl group in the urethane (meth) acrylate (A) and an isocyanate group in the polyisocyanate compound (C), the urethane bond and the isocyanate group There is a cross-linked structure due to allophanate bonds, etc., and such a cross-linked structure gradually increases, and after 3 to 7 days, finally reaches the required adhesive force, so-called final adhesive force is maintained. The inventor thinks.

  The adherend of the curable resin composition for adhesives of the present invention is not particularly limited, and examples thereof include acrylic resins such as methyl methacrylate copolymers, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and the like. Polyester resin, triacetyl cellulose and the like. Moreover, polycarbonate resin, styrene resin, ABS resin, polyolefin, polysulfone resin, polyethersulfone resin, vinyl chloride resin, polymethacrylimide resin, glass, metal, and the like can be given.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. All parts and percentages in the examples are by weight unless otherwise specified.

Synthesis Example 1 [Synthesis of hydroxyl group-containing urethane (meth) acrylate (A)]
Polyester diol obtained by reacting 3-methyl-1,5-pentanediol and adipic acid in a flask equipped with a thermometer, a stirrer, and a condenser (number average molecular weight = 2000, hydroxyl value (OH value)) = 56.1 mgKOH / g) 300 g and dibutyltin diacetate 0.09 g were charged, the temperature was raised to 80 ° C. with stirring, and then 33.3 g of isophorone diisocyanate was added over 30 minutes while paying attention to heat generation. After the addition, the reaction was performed for 2 hours, and then 17.4 g of hydroxyethyl acrylate was added, and the reaction was further performed for 5 hours to obtain a hydroxyl group-containing urethane (meth) acrylate (A-1). The number average molecular weight of (A-1) was 2338, and the hydroxyl value was 24.0 mgKOH / g.

Synthesis example 2 (same as above)
Polyester diol obtained by reacting 3-methyl-1,5-pentanediol and adipic acid in a flask equipped with a thermometer, a stirrer, and a condenser (number average molecular weight = 1200, hydroxyl value (OH value)) = 93.5 mg KOH / g) 300 g and dibutyltin diacetate 0.18 g were charged, the temperature was raised to 80 ° C. with stirring, and then 111 g of isophorone diisocyanate was added over 30 minutes while paying attention to heat generation. After the addition, the reaction was carried out for 2 hours, after which 29 g of hydroxyethyl acrylate was added, and the reaction was further carried out for 5 hours to obtain a hydroxyl group-containing urethane (meth) acrylate (A-2). The number average molecular weight of (A-2) was 1538, and the hydroxyl value was 36.5 mgKOH / g.

Synthesis example 3 (same as above)
Polyester diol obtained by reacting 3-methyl-1,5-pentanediol and adipic acid in a flask equipped with a thermometer, a stirrer, and a condenser (number average molecular weight = 6800, hydroxyl value (OH value)) = 16.5 mg KOH / g) 500 g and dibutyltin diacetate 0.18 g were charged, the temperature was raised to 80 ° C. with stirring, and then 16.3 g of isophorone diisocyanate was added over 30 minutes while paying attention to heat generation. After the addition, the reaction was carried out for 2 hours, then 8.5 g of hydroxyethyl acrylate was added, and the reaction was further carried out for 5 hours to obtain a hydroxyl group-containing urethane (meth) acrylate (A-3). The number average molecular weight of (A-3) was 7138, and the hydroxyl value was 7.9 mgKOH / g.

Synthesis Example 4 [Synthesis of hydroxyl group-containing urethane (meth) acrylate (A)]
In a flask equipped with a thermometer, a stirrer, and a condenser, polycaprolactone diol (number average molecular weight = 2000, hydroxyl value (OH value) = 55.9 mgKOH / g) as a polyester diol and 300 g of dibutyltin diacetate The mixture was heated to 80 ° C. with stirring, and then 26.1 g of 2,4-tolylene diisocyanate was added over 30 minutes while paying attention to heat generation. After the addition, the reaction was performed for 2 hours, and then 17.4 g of hydroxyethyl acrylate was added, and the reaction was further performed for 5 hours to obtain a hydroxyl group-containing urethane (meth) acrylate (A-4). The number average molecular weight of (A-4) was 2290, and the hydroxyl value was 24.5 mgKOH / g.

Synthesis Example 5 [Synthesis of urethane (meth) acrylate (A ′) for comparison]
Polyester diol obtained by reacting 3-methyl-1,5-pentanediol and adipic acid in a flask equipped with a thermometer, a stirrer and a condenser (number average molecular weight = 2000, OH value = 56.1 mgKOH) / G) 300 g and 0.09 g of dibutyltin diacetate were charged, the temperature was raised to 80 ° C. with stirring, and 66.6 g of isophorone diisocyanate was added over 30 minutes while paying attention to heat generation. After the addition, the reaction was carried out for 2 hours, after which 34.8 g of hydroxyethyl acrylate was added, and the reaction was further carried out for 5 hours. It was confirmed by the infrared absorption spectrum that the absorption of the isocyanate group had disappeared, and urethane (meth) acrylate (A′-1) containing no hydroxyl group was obtained. The number average molecular weight of (A′-1) was 2560.

Synthesis example 6 (same as above)
Polyester diol obtained by reacting 3-methyl-1,5-pentanediol and adipic acid in a flask equipped with a thermometer, a stirrer, and a condenser (number average molecular weight = 800, hydroxyl value (OH value)) = 140.3 mg KOH / g) 300 g and dibutyltin diacetate 0.18 g were charged, the temperature was raised to 80 ° C. with stirring, and then 83.3 g of isophorone diisocyanate was added over 30 minutes while paying attention to heat generation. After the addition, the reaction was carried out for 2 hours, after which 43.5 g of hydroxyethyl acrylate was added, and the reaction was further carried out for 5 hours to obtain a hydroxyl group-containing urethane (meth) acrylate (A′-2). The number average molecular weight of (A′-2) was 1138, and the hydroxyl value was 49.3 mgKOH / g.

Synthesis example 7 (same as above)
Polyester diol obtained by reacting 3-methyl-1,5-pentanediol and adipic acid in a flask equipped with a thermometer, a stirrer, and a condenser (number average molecular weight = 7200, hydroxyl value (OH value)) = 15.6 mg KOH / g) 500 g and dibutyltin diacetate 0.18 g were charged, the temperature was raised to 80 ° C. with stirring, and then 15.4 g of isophorone diisocyanate was added over 30 minutes while paying attention to heat generation. After the addition, the reaction was carried out for 2 hours, and then 8.1 g of hydroxyethyl acrylate was added, and the reaction was further carried out for 5 hours to obtain a hydroxyl group-containing urethane (meth) acrylate (A′-3). The number average molecular weight of (A-3) was 7538, and the hydroxyl value was 7.4 mgKOH / g.

Synthesis Example 8 (Synthesis of an ethylenically unsaturated group-containing acrylic resin for comparison)
A flask equipped with a thermometer, a stirrer, and a condenser was charged with 65 g of n-butyl acrylate, 5 g of n-butyl methacrylate, 20 g of acrylic acid, 10 g of dimethylacrylamide, and 100 g of ethyl acetate. The reaction was performed for 3 hours. Subsequently, 0.07 g of azobisisobutyronitrile dissolved in 5 g of toluene was added, and the mixture was further reacted at reflux temperature for 4 hours. Then, it diluted with toluene and obtained the acrylic resin of the resin part 40% and the weight average molecular weight 350,000 of polystyrene conversion by GPC.

  100 g of this acrylic resin solution (resin content 40%) is charged with 0.004 g of di-n-butyltin dilaurate, 0.006 g of butylhydroxytoluene and 5.17 g of 2-methacryloyloxyethyl isocyanate as a functional group-containing unsaturated compound. The reaction was carried out at 50 ° C. for 20 hours, diluted with toluene, and an acrylic resin (A′-4) solution (resin content 40) having 30 mol% of ethylenically unsaturated groups added to the side chain with respect to acrylic acid. %).

Synthesis Example 9 [Synthesis of urethane (meth) acrylate oligomer for comparison]
In a flask equipped with a thermometer, stirrer, and condenser, a 65% xylene solution of polymethyl methacrylate diol (number average molecular weight of acrylic polyol = 1000, hydroxyl value (OH value) in terms of resin content = 155 mgKOH / g) 73 g , 18.7 g of isophorone diisocyanate was added, and the reaction was carried out at 90 ° C. for 5 hours with stirring. Thereafter, 8.3 g of 4-hydroxybutyl acrylate was added, and the reaction was further carried out for 4 hours, and polymethyl methacrylate diol, isophorone diisocyanate and The urethane (meth) acrylate (A'-5) which does not contain the hydroxyl group of reaction molar ratio = 2: 3: 2.05 of 4-hydroxybutyl acrylate was obtained. The number average molecular weight of (A′-5) was 3000.

Example 1
A curable resin composition 1 for an adhesive was prepared according to the formulation shown in Table 1. The viscosity and refractive index of this curable resin composition 1 for adhesives, 360 nm transmittance and adhesive strength were evaluated. The measurement method is shown below. The measurement results are shown in Table 1.

<Measurement of viscosity>
Using an E-type rotational viscometer, viscosity measurement (mPa · s) at 25 ° C. was performed.

<Measurement of refractive index>
It apply | coated directly to the prism of the Abbe refractometer and measured at 25 degreeC.

<360 nm transmittance>
The adhesive curable resin composition 1 was applied to a 125 μm thick transparent PET film (both sides easy-adhesion treatment) to a film thickness of 100 μm, and then an ultra-high pressure mercury lamp was used to apply 500 mJ / cm ² ultraviolet light for the adhesive. Irradiation from the curable resin composition 1 side was carried out and ultraviolet curing was carried out. Then, it left still for 3 hours in 23 degreeC and 50% RH environment, and prepared the test piece. Using this test piece, the light transmittance at 360 nm was measured, ◎ when the transmittance was 75% or more, ○ when 65% or more and less than 75%, and Δ when 55% or more and less than 65%. , Less than 55% was rated as x.

<Measurement of adhesive strength>
1. Adhesive strength in a temporary adhesion state A curable resin composition 1 for adhesive is placed between a 15 cm square and 125 μm thick transparent PET film (double-sided easy adhesion treatment) and a 15 cm square and 2.0 mm thick acrylic resin plate. After putting both plastic substrates together so as to have a film thickness of 100 μm, ultraviolet rays of 500 mJ / cm ² were irradiated from the PET film side with an ultra-high pressure mercury lamp to cure the ultraviolet rays. Then, it left still for 3 hours in 23 degreeC and 50% RH environment, and prepared the test piece. Using this test piece, the adhesive strength was measured according to JIS K6854. The measurement was performed by a peeling method using a tensile tester in an environment of 23 ° C. and 50% RH at a tensile speed of 300 mm / min and a test distance of 50 mm. When the peel strength is 0.1 N / cm or more and less than 2.0 N / cm, ◎, when the peel strength is 2.0 N / cm or more and less than 3.0 N / cm, ○, 3.0 N / cm or more to 5.0 N / cm The case of less than cm was Δ, and the case of 5.0 N / cm or more was rated as x.

2. Adhesive strength in the final adhesion state The curable resin composition 1 for adhesive is made to have a film thickness of 100 μm between a transparent PET film having a thickness of 125 μm (double-sided easy adhesion treatment) and an acrylic resin plate having a thickness of 2.0 mm. The two plastic substrates were bonded together and then cured with ultraviolet rays of 500 mJ / cm ² from the PET film side with an ultra-high pressure mercury lamp. Then, it left still in 60 degreeC oven for 15 hours, took out, returned to room temperature, and prepared the test piece. Using this test piece, the adhesive strength was measured according to JIS K6854. The measurement was performed by a peeling method using a tensile tester in an environment of 23 ° C. and 50% RH at a tensile speed of 300 mm / min and a test distance of 50 mm. ◎ when peel strength is 8.0 N / cm or more, ◯ when 6.0 N / cm or more and less than 8.0 N / cm, Δ when 4.0 N / cm or more and less than 6.0 N / cm, The case of less than 6.0 N / cm was set as x.

Examples 2-5 and Comparative Examples 1-3
In the same manner as in Example 1, curable resin compositions 2 to 5 for adhesive and curable resin compositions 1 to 3 for comparative adhesive were prepared according to the formulation shown in Table 1. In the same manner as in Example 1, the viscosity, refractive index, and adhesive strength of the curable resin composition for adhesive were evaluated. The measurement results are shown in Tables 1 and 2.

Comparative Example 4
In a room where the ultraviolet rays were blocked, 24 parts of toluene and 26 parts of the urethane acrylate oligomer solution (A′-5) were placed in a 250 ml polyethylene container, dissolved at 40 ° C., and then containing the ethylenically unsaturated group. 50 parts of a solution of acrylic resin (A′-4) (resin content 40%), 1.5 parts of 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator, 55% acetic acid of tolylene diisocyanate adduct of trimethylolpropane 1.5 parts of an ethyl solution was added and stirred to obtain a uniform solution, and a curable resin composition 4 for a comparative adhesive was prepared. The 360 nm transmittance and adhesive strength of this comparative control curable resin composition 4 were evaluated. The measurement method is shown below. The measurement results are shown in Table 2.

<360 nm transmittance>
The adhesive curable resin composition 1 was applied to a 125 μm-thick transparent PET film (double-sided easy adhesion treatment) so as to have a film thickness of 100 μm, and dried by heating at 100 ° C. for 2 minutes. Thereafter, ultraviolet rays of 500 mJ / cm ² were irradiated from the side of the comparative adhesive curable resin composition 4 with an ultra-high pressure mercury lamp to cure the ultraviolet rays. Then, it left still for 3 hours in 23 degreeC and 50% RH environment, and prepared the test piece. Using this test piece, the light transmittance at 360 nm was measured, ◎ when the transmittance was 75% or more, ○ when 65% or more and less than 75%, and Δ when 55% or more and less than 65%. , Less than 55% was rated as x.

<Measurement of adhesive strength>
1. Adhesive strength in the temporary adhesion state The curable resin composition 4 for adhesive for comparison and control was applied on a PET separator having a thickness of 38 μm and subjected to a silicone release treatment of 15 cm square so that the thickness after drying was 100 μm. Heat drying at 100 ° C. for 2 minutes. After that, it was transferred to a transparent PET film (double-sided easy adhesion treatment) having a thickness of 15 cm and a thickness of 125 μm, and aged at 40 ° C. for 3 days to prepare an adhesive sheet. Next, after peeling off the PET separator of the adhesive sheet, the adhesive sheet was pressure-bonded to an acrylic resin plate having a thickness of 15 cm and a thickness of 2.0 mm, and both plastic substrates were bonded together. UV curing was performed by irradiating UV light of / cm ² from the PET film side. Then, it left still for 3 hours in 23 degreeC and 50% RH environment, and prepared the test piece. Using this test piece, the adhesive strength was measured according to JIS K6854. The measurement was performed by a peeling method using a tensile tester in an environment of 23 ° C. and 50% RH at a tensile speed of 300 mm / min and a test distance of 50 mm. When the peel strength is 0.1 N / cm or more and less than 2.0 N / cm, ◎, when the peel strength is 2.0 N / cm or more and less than 3.0 N / cm, ○, 3.0 N / cm or more to 5.0 N / cm The case of less than cm was Δ, and the case of 5.0 N / cm or more was rated as x.

2. Adhesive strength in the final adhesion state The curable resin composition 4 for adhesive for comparison and control was coated on a 15 cm square silicone release-treated PET separator having a thickness of 38 μm so that the thickness after drying was 100 μm. Heat drying at 100 ° C. for 2 minutes. After that, it was transferred to a transparent PET film (double-sided easy adhesion treatment) having a thickness of 15 cm and a thickness of 125 μm, and aged at 40 ° C. for 3 days to prepare an adhesive sheet. Next, after peeling off the PET separator of the adhesive sheet, the adhesive sheet was pressure-bonded to an acrylic resin plate having a thickness of 15 cm and a thickness of 2.0 mm, and both plastic substrates were bonded together. UV curing was performed by irradiating UV light of / cm ² from the PET film side. Then, it left still in 60 degreeC oven for 15 hours, took out, returned to room temperature, and prepared the test piece. Using this test piece, the adhesive strength was measured according to JIS K6854. The measurement was performed by a peeling method using a tensile tester in an environment of 23 ° C. and 50% RH at a tensile speed of 300 mm / min and a test distance of 50 mm. ◎ when peel strength is 8.0 N / cm or more, ◯ when 6.0 N / cm or more and less than 8.0 N / cm, Δ when 4.0 N / cm or more and less than 6.0 N / cm, The case of less than 4.0 N / cm was evaluated as x.

<Footnotes in Table 1>
(B-1): Phenoxyethyl acrylate (B-2): Isobornyl acrylate (C-1): Isocyanurate type polyisocyanate of hexamethylene diisocyanate (C-2): Tolylene diisocyanate adduct of trimethylolpropane 55% ethyl acetate solution (D-1): 1-hydroxycyclohexyl phenyl ketone (D-2): 2,4,6-trimethylbenzoyldiphenylphosphine oxide

Claims (14)

Hydroxyl group-containing urethane (meth) acrylate (A) obtained by reacting a diol compound (a1) having a molecular weight of 1,000 to 7,000, a polyisocyanate compound (a2) and a hydroxyl group-containing (meth) acrylate compound (a3). And a monomer (B) having an ethylenically unsaturated double bond, a polyisocyanate compound (C), and a photopolymerization initiator (D). The curable resin composition for an adhesive according to claim 1, wherein the hydroxyl group-containing urethane (meth) acrylate (A) is a urethane (meth) acrylate having a hydroxyl value of 7.0 to 42.0 mgKOH / g. The urethane (meth) acrylate (A) uses a polyester diol as the diol compound (a1) and uses an aliphatic polyisocyanate compound and / or a cyclic aliphatic polyisocyanate compound as the polyisocyanate compound (a2). The curable resin composition for an adhesive according to claim 1 or 2, which is a hydroxyl group-containing urethane (meth) acrylate having a number average molecular weight of 1,500 to 10,000. The curable resin composition for an adhesive according to claim 3, wherein the polyisocyanate compound (a2) is 2,4-tolylene diisocyanate and / or isophorone diisocyanate. 4. The polyester diol obtained by reacting a dihydric alcohol and a dibasic acid, wherein the polyester diol is obtained using 3-methyl-1,5-pentanediol as the dihydric alcohol. Or the curable resin composition for adhesives of 4. The urethane (meth) acrylate (A) content is the urethane (meth) acrylate (A), a monomer (B) having an ethylenically unsaturated double bond, a polyisocyanate compound (C), and a photopolymerization initiator. The curable resin composition for an adhesive according to claim 1, wherein the content is 10 to 80% by weight based on the total weight of (D). The curable resin composition for an adhesive according to any one of claims 1 to 6, wherein the diol compound (a1) is a diol having a molecular weight of 1,000 to 5,000. The curable resin composition for an adhesive according to any one of claims 1 to 7, wherein the monomer (B) having an ethylenically unsaturated double bond is a monofunctional (meth) acrylate having a cyclic structure. The curable resin composition for an adhesive according to claim 8, wherein the monofunctional (meth) acrylate having a cyclic structure is phenoxyethyl (meth) acrylate and / or isobornyl (meth) acrylate. The content of the monomer (B) having an ethylenically unsaturated double bond is the urethane (meth) acrylate (A), the monomer (B) having an ethylenically unsaturated double bond, a polyisocyanate compound ( The curable resin composition for an adhesive according to claim 1, which is 20 to 90% by weight based on the total weight of C) and the photopolymerization initiator (D). The curable resin composition for an adhesive according to claim 1, wherein the polyisocyanate compound (C) is a polyisocyanate compound having three or more isocyanate groups. The curable resin composition for an adhesive according to claim 11, wherein the polyisocyanate compound having three or more isocyanate groups is an isocyanurate type polyisocyanate of hexamethylene diisocyanate. The content of the polyisocyanate compound (C) is the urethane (meth) acrylate (A), the monomer (B) having an ethylenically unsaturated double bond, the polyisocyanate compound (C), and a photopolymerization initiator (D The curable resin composition for an adhesive according to claim 1, which is 0.5 to 15% by weight based on the total weight of The curable resin composition for an adhesive according to claim 1, wherein the photopolymerization initiator (D) is a phosphine oxide photopolymerization initiator.