JP2011190421A - Active energy ray-curable adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active energy ray-curable adhesive composition having excellent heat resistance, moisture resistance and light resistance. <P>SOLUTION: The active energy ray-curable adhesive composition includes: a urethane (meth)acrylate (A), obtained by the reaction of a polyol (a1) having no aromatic ring and having a specified structure, an isocyanate compound (a2), and a (meth)acrylic acid ester (a3) having a hydroxyl group; a (meth)acrylic acid ester (B) having a substituted or nonsubstituted cyclic saturated hydrocarbon group; and a (meth)acrylic acid ester (C) having a substituted or nonsubstituted saturated heterocyclic group having oxygen atom. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an active energy ray-curable adhesive composition. More specifically, the present invention relates to an active energy ray-curable adhesive composition having excellent heat resistance, moisture resistance, and light resistance. The active energy ray-curable adhesive composition of the present invention can be suitably used particularly for bonding optical films of display devices.

  Active energy ray-curable adhesive that cures by irradiation with active energy rays such as ultraviolet rays and visible rays is easy to operate because it has a short curing time of one second and is one-component, and does not require a solvent. Transparent plastics can be used in a wide range of fields such as electrical, electronics, automobiles, furniture, and precision machinery because it has the advantage of being able to reduce environmental pollution and curing shrinkage and is more energy efficient than thermal curing. It is used as an adhesive.

  In particular, in recent years, liquid crystal displays (LCD: Liquid Crystal Display), plasma display panels (PDP: Plasma Display Panel), organic EL displays (OELD: Organic Electroluminescent Display), etc. have been widely spread in the market, and these display devices are attracting attention. Active energy curable adhesives are also used for bonding optical films and the like. For example, Patent Document 1 discloses an active energy ray-curable adhesive comprising a urethane (meth) acrylate having a polyester polyol or polycarbonate polyol skeleton and a specific monofunctional (meth) acrylate having a cyclic structure as essential components. Compositions have been proposed. According to the adhesive composition, excellent adhesive force can be maintained even under high temperature and high humidity conditions, and coloring over time can be reduced.

International Publication No. 2006/118078 Pamphlet

  However, even with the adhesive composition described in Patent Document 1, under severe conditions involving high temperature, high humidity, and light irradiation, it is not possible to sufficiently prevent deterioration or coloring of adhesive performance to a desired level. It was not possible, and further improvement was demanded.

  Then, an object of this invention is to provide the active energy ray hardening-type adhesive composition which has the outstanding heat resistance, moisture resistance, and light resistance.

  As a result of intensive studies to achieve the above object, the present inventors have achieved excellent heat resistance and moisture resistance by combining two specific urethane (meth) acrylates and two specific (meth) acrylic acid esters. The present invention has been completed by finding that an active energy ray-curable adhesive composition having both properties and light resistance can be obtained.

  That is, the active energy ray-curable adhesive composition of the present invention includes urethane (meth) acrylate (A), (meth) acrylic acid ester (B), and (meth) acrylic acid ester (C). . The urethane (meth) acrylate (A) comprises at least one selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, and hydrogenated polybutadiene polyols having terminal hydroxyl groups and no aromatic rings. It is obtained by the reaction of the polyol (a1) having a skeleton, the isocyanate compound (a2), and the (meth) acrylate (a3) having a hydroxyl group. The (meth) acrylic acid ester (B) is represented by the following chemical formula (1), and the (meth) acrylic acid ester (C) is represented by the following formula (2).

In the chemical formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a substituted or unsubstituted cyclic saturated hydrocarbon group.

In the chemical formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents a substituted or unsubstituted saturated heterocyclic group containing an oxygen atom.

  ADVANTAGE OF THE INVENTION According to this invention, the active energy ray hardening-type adhesive composition which has the outstanding heat resistance, moisture resistance, and light resistance can be provided.

  Hereinafter, preferred embodiments of the present invention will be described.

  One form of the present invention is an active energy ray-curable adhesive composition comprising urethane (meth) acrylate (A), (meth) acrylic acid ester (B), and (meth) acrylic acid ester (C). (Hereinafter, also simply referred to as “adhesive composition”).

  The urethane (meth) acrylate (A) has at least one selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, and hydrogenated polybutadiene polyols having a terminal hydroxyl group and no aromatic ring as a skeleton. It is obtained by the reaction of the polyol (a1) having, the isocyanate compound (a2), and the (meth) acrylate (a3) having a hydroxyl group.

  The (meth) acrylic acid ester (B) is represented by the following chemical formula (1).

In the chemical formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a substituted or unsubstituted cyclic saturated hydrocarbon group.

  The (meth) acrylic acid ester (C) is represented by the following chemical formula (2).

In the chemical formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents a substituted or unsubstituted saturated heterocyclic group containing an oxygen atom.

  Hereinafter, although this form is demonstrated, the technical scope of this invention should be defined based on description of a claim, and is not restrict | limited only to the following form.

<Adhesive composition>
The adhesive composition of this embodiment essentially includes urethane (meth) acrylate (A), (meth) acrylic acid ester (B), and (meth) acrylic acid ester (C), and optionally other additives. May be included.

[Urethane (meth) acrylate (A)]
Urethane (meth) acrylate (A) contributes mainly to adhesiveness in the adhesive composition of this embodiment. The urethane (meth) acrylate (A) according to this embodiment has at least one selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, and hydrogenated polybutadiene polyols having terminal hydroxyl groups and no aromatic rings. It is obtained by a reaction between a polyol (a1) having a seed as a skeleton, an isocyanate compound (a2), and a (meth) acrylate (a3) having a hydroxyl group.

  The basic structure of the bifunctional urethane (meth) acrylate (A) according to one embodiment of the present invention is shown in the following chemical formula (3).

According to the above chemical formula (3), the segment (S1) derived from the polyol (a1) having the linear skeleton R ⁵ and the segment (S2) derived from the isocyanate compound (a2) present on both sides of the segment (S1) Are connected to each other through a urethane bond. And the other end of segment (S2) and the segment (S3) derived from the (meth) acrylate (a3) having a hydroxyl group are bonded via a urethane bond.

  The polyol (a1) mainly contributes to the flexibility of the adhesive composition. The polyol (a1) has a terminal hydroxyl group for forming a urethane bond with the isocyanate compound (a2). When a bifunctional urethane (meth) acrylate such as the chemical formula (3) is used, the polyol (a1) has one hydroxyl group at each of both ends of the skeleton. In this embodiment, it is essential that the polyol (a1) does not have an aromatic ring. This is because if an aromatic ring is included, the light resistance may deteriorate.

  Furthermore, it is essential to have at least one selected from the group consisting of polyether polyol, polyester polyol, polycarbonate polyol, and hydrogenated polybutadiene polyol as the polyol (a1). Among these, from the viewpoint of improving flexibility, it is preferable to have at least one selected from the group consisting of polyether polyols and polyester polyols. In addition, these polyols may be used individually by 1 type, and 2 or more types may be used together.

  The polyether polyol having no aromatic ring is not particularly limited, and examples thereof include polypropylene glycol, polytetramethylene glycol, and polyethylene glycol.

  Although there is no restriction | limiting in particular in the polyester polyol which does not have an aromatic ring, For example, what can be obtained by esterifying the polyhydric carboxylic acid and polyhydric alcohol which do not have an aromatic ring can be used.

  Examples of the polyvalent carboxylic acid having no aromatic ring that can be a raw material for the polyester polyol include, for example, adipic acid, sebacic acid, succinic acid, tetrahydrophthalic acid, tetrahydrophthalic anhydride, fumaric acid, maleic acid, maleic anhydride, And itaconic acid. These may be used alone or in combination of two or more.

  Examples of the polyhydric alcohol that can be a raw material for the polyester polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, and 3-methyl. Examples thereof include 1,5-pentanediol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, dimethylolpropionic acid, dimethylolbutanoic acid, and alkylene oxide adducts thereof. These may be used alone or in combination of two or more.

  The polycarbonate polyol having no aromatic ring is not particularly limited, and examples thereof include those obtained by the reaction of a low molecular weight diol having no aromatic ring and a dialkyl ester having no aromatic ring, and caprolactone and aromatic. A copolymer of a low molecular weight diol containing no aromatic ring with a polycarbonate polyol can be used.

  Examples of the low molecular weight diol having no aromatic ring that can be a raw material for the polycarbonate polyol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene glycol. , Butylene glycol, polybutylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and the like. These may be used alone or in combination of two or more.

  Examples of the carbonic acid dialkyl ester having no aromatic ring that can be a raw material for the polycarbonate polyol include ethylene carbonate and carbonic acid dibutyl ester. These may be used alone or in combination of two or more.

  Examples of the hydrogenated polybutadiene polyol include hydrogenated terminal hydroxylated polybutadiene diol resins mainly having 1,4-bonds, terminal hydroxylated polybutadiene diol resins mainly having 1,2-bonds, or mixtures thereof. Etc. can be used.

  The number average molecular weight of the polyol (a) is preferably 1000 to 10,000, and more preferably 1500 to 3000. When the number average molecular weight is in such a range, an adhesive composition having excellent adhesiveness can be obtained. In addition, in this invention, the value measured by the gel permeation chromatography method (GPC method) (polystyrene conversion) shall be employ | adopted for a number average molecular weight.

  The isocyanate compound (a2) mainly contributes to the adhesive strength of the adhesive composition. In the case of a bifunctional urethane (meth) acrylate such as the chemical formula (3) described above, the isocyanate compound (a2) has two isocyanate groups.

  A known compound can be used as the isocyanate compound (a2). Examples thereof include known ones such as tolylene diisocyanate, hydrogenated polydiisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, and paraphenylene diisocyanate. Among these, from the viewpoint of light resistance, it is preferable to include hydrogenated polydiisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, or isophorone diisocyanate that does not have an aromatic ring. As for these isocyanate compounds (a2), only 1 type may be used independently and 2 or more types may be used together.

  (Meth) acrylate (a3) mainly contributes to the adhesive strength of the adhesive composition. The (meth) acrylate (a3) has at least one hydroxyl group to form a urethane bond with the segment (S2) as in the above chemical formula (3).

  There is no restriction | limiting in particular as such (meth) acrylate (a3), A well-known compound can be used without a restriction | limiting. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, butanediol mono (meth) acrylate, caprolactone modified product of 2-hydroxyethyl (meth) acrylate, glycidol di (meth) acrylate, and penta Examples include erythritol tri (meth) acrylate. These (meth) acrylates (a3) may be used alone or in combination of two or more.

  The content of the urethane (meth) acrylate (A) in the adhesive composition of the present embodiment is preferably 5 to 60% by mass with respect to the total mass of the adhesive composition, and is 20 to 50% by mass. More preferably, it is more preferable that it is 25-40 mass%. It can be set as the adhesive composition excellent in adhesive force as content of urethane (meth) acrylate (A) is such a range.

  The urethane (meth) acrylate (A) according to this embodiment can be produced by appropriately adopting a conventionally known method. As a general production method, the polyol (a1) and the isocyanate compound (a2) are stirred for 4 to 6 hours while heating at 70 to 80 ° C. Thereafter, urethane (meth) acrylate (A) can be synthesized by further adding (meth) acrylate (a3) and stirring for 4 to 6 hours while heating at 70 to 80 ° C.

  At this time, the charged amounts of the polyol (a1), the isocyanate compound (a2), and the (meth) acrylate (a3) are 62.0 to 96.9% by mass, respectively, when the total mass is 100% by mass, It is preferable that they are 2.5-25.2 mass% and 0.4-11.7 mass%. It can be set as the adhesive composition excellent in adhesive force as the ratio of each component is such a range.

  Moreover, it is preferable that it is 2000-50000, and, as for the number average molecular weight of urethane (meth) acrylate (A), it is more preferable that it is 3000-15000. When the number average molecular weight is in such a range, an adhesive composition having excellent adhesive strength can be obtained.

[(Meth) acrylic acid ester (B)]
The (meth) acrylic acid ester (B) mainly has a role of imparting strength in the adhesive composition of this embodiment. The (meth) acrylic acid ester (B) according to this embodiment has a structure represented by the following chemical formula (1).

In the chemical formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a substituted or unsubstituted cyclic saturated hydrocarbon group.

  The cyclic saturated hydrocarbon group is not particularly limited, but is at least one selected from the group consisting of monocyclic saturated hydrocarbon groups having 5 to 10 carbon atoms and polycyclic saturated hydrocarbon groups. Is preferred. Examples of the monocyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic saturated hydrocarbon group include a norbornyl group, an isobornyl group, an adamantyl group, a tricyclodecyl group, a dicyclopentanyl group, and a tricyclopentanyl group.

  Examples of the substituent that may be present in the cyclic saturated hydrocarbon group include a halogen atom, acyl group, alkyl group, phenyl group, alkoxy group, halogenated alkyl group, halogenated alkoxy group, carbonyl group, alkoxycarbonyl group, Examples thereof include, but are not limited to, alkoxysulfonyl groups, alkylthio groups, aryloxycarbonyl groups, oxyalkyl ether groups and the like.

  Some of the above substituents are shown below with more specific examples. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the acyl group include acetyl group, ethylcarbonyl group, propylcarbonyl group, butylcarbonyl group, pentylcarbonyl group, hexylcarbonyl group, benzoyl group, and pt-butylbenzoyl group. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, 1, 2-dimethylpropyl group, n-hexyl group, cyclohexyl group, 1,3-dimethylbutyl group, 1-isopropylpropyl group, 1,2-dimethylbutyl group, n-heptyl group, 1,4-dimethylpentyl group, 2 -Methyl-1-isopropylpropyl group, 1-ethyl-3-methylbutyl group, n-octyl group, 2-ethylhexyl group and the like can be mentioned. Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, isopentyloxy, neo Examples include pentyloxy group, 1,2-dimethyl-propoxy group, n-hexyloxy group, cyclohexyloxy group, 1,3-dimethylbutoxy group, 1-isopropylpropoxy group and the like. Examples of the halogenated alkyl group include a chloromethyl group, a bromomethyl group, a trifluoromethyl group, a chloroethyl group, a 2,2,2-trichloroethyl group, a bromoethyl group, a chloropropyl group, and a bromopropyl group. Examples of the halogenated alkoxy group include chloromethoxy group, bromomethoxy group, trifluoromethoxy group, chloroethoxy group, 2,2,2-trichloroethoxy group, bromoethoxy group, chloropropoxy group, bromopropoxy group and the like. Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an isopropoxycarbonyl group, an n-butoxycarbonyl group, an isobutoxycarbonyl group, a sec-butoxycarbonyl group, and a tert-butoxycarbonyl group. It is done.

  The content of the (meth) acrylic acid ester (B) in the adhesive composition of the present embodiment is preferably 5 to 90% by mass, and 10 to 70% by mass with respect to the total mass of the adhesive composition. More preferably, it is more preferably 30 to 60% by mass. When the content of the (meth) acrylic acid ester (B) is 90% or less, the adhesive composition does not become too hard, and excellent adhesive force can be ensured. Moreover, it can be set as the adhesive composition excellent in heat resistance and heat-and-moisture resistance in content of (meth) acrylic acid ester (B) being 5% or more.

[(Meth) acrylic acid ester (C)]
The (meth) acrylic acid ester (C) mainly has a role of imparting tackiness to the adhesive composition of this embodiment. The (meth) acrylic acid ester (C) according to this embodiment has a structure represented by the following chemical formula (2).

In the chemical formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents a substituted or unsubstituted saturated heterocyclic group containing an oxygen atom.

  The saturated heterocyclic group containing an oxygen atom is not particularly limited, and examples thereof include a tetrahydrofurfuryl group, a tetrahydropyranyl group, an epoxy group, a glycidyl group, an α-lactone group, a β-lactone group, and a γ-lactone. Group, δ-lactone group, ε-caprolactone group, dioxolane group, dioxane group and the like.

  Further, as the substituent that may be present in the saturated heterocyclic group containing an oxygen atom, the same substituents as those that may be present in the above-mentioned cyclic saturated hydrocarbon group can be used without limitation. The detailed explanation is omitted.

  The content of the (meth) acrylic acid ester (C) in the adhesive composition of this embodiment is preferably 5 to 80% by mass, and 10 to 60% by mass with respect to the total mass of the adhesive composition. More preferably, it is more preferably 15 to 40% by mass. When the content of (meth) acrylic acid ester (C) is 80% or less, the adhesive composition does not become too soft, and heat resistance and moist heat resistance can be maintained. Moreover, it can be set as the adhesive composition excellent in adhesive force as content of (meth) acrylic acid ester (C) is 5% or more.

  The method for producing the adhesive composition of the present embodiment is not particularly limited, and the above-mentioned urethane (meth) acrylate (A), (meth) acrylic ester (B), and (meth) acrylic ester (C), and If necessary, it can be obtained by mixing a predetermined amount of other additives. As the additive, for example, a leveling agent, a surface lubricant, an antifoaming agent, a light stabilizer, an antioxidant, a plasticizer, a polymerization inhibitor, an antistatic agent, a filler and the like can be used.

<Adhesion method>
The other form of this invention is related with the adhesion | attachment method using the above-mentioned active energy ray hardening-type adhesive composition. That is, in the bonding method of the present embodiment, the first substrate and the second substrate are bonded to each other through the mixture of the active energy ray-curable adhesive composition and the photopolymerization initiator. And then irradiating the mixture with active energy rays.

  There is no restriction | limiting in particular in the photoinitiator used for this form, A conventionally well-known compound can be employ | adopted suitably. For example, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone, 2-hydroxy Acetophenones such as 2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; benzopheno , Methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 2,4, Benzophenones such as 6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium chloride 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy) -3, 4-Dimethyl-9H Thioxanthones such as thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, bis Examples include acylphosphonoxides such as (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. Only 1 type of these photoinitiators may be used independently, and 2 or more types may be used together.

  The addition amount of the photopolymerization initiator is preferably 0.5 to 10% by mass and more preferably 2 to 5% by mass with respect to the total mass of the adhesive composition. In addition, the method for mixing the adhesive composition and the photopolymerization initiator is not particularly limited.

  Next, the 1st base material and the 2nd base material are bonded together via the mixture containing an adhesive composition and a photoinitiator. Base materials include polyesters such as vinyl chloride and polyethylene terephthalate, plastic films or plastic sheets such as (meth) acrylic resins such as polypropylene, polyether nitrile, and polymethyl methacrylate, polycarbonate resins, and polystyrene resins, glass plates, copper plates , Aluminum plate, iron plate, and paper. The substrates to be bonded may be the same type of material or different materials, but at least a part of the substrate is a material that can transmit the active energy rays necessary for curing the adhesive composition. Need to be.

  The method for applying the mixture to these substrates is not particularly limited, and conventionally known methods such as a die coater method, a screen printing method, a doctor blade method, and a spray method can be used.

Thereafter, the mixture is irradiated with active energy rays. Examples of active energy rays include ultraviolet rays and visible rays. For irradiation with these active energy rays, an ultra-high pressure mercury lamp, a metal halide lamp, a (pulse) xenon lamp, an electrodeless lamp, or the like can be used. The amount of light to be irradiated can be appropriately adjusted depending on the type of base material or the coating amount of the adhesive composition, but is usually about 500 to 1000 mJ / cm ² .

  The adhesive composition of this embodiment is excellent in adhesion ability, and maintains excellent adhesion ability even when exposed to high temperature, high humidity, or light irradiation conditions, and is difficult to be colored. Therefore, the adhesive composition or bonding method of this embodiment can be particularly suitably used for bonding optical films of display devices such as liquid crystal displays, plasma displays, and organic EL displays.

  The effect of this invention is demonstrated using a following example and a comparative example. However, the technical scope of the present invention is not limited only to the following examples.

<Synthesis of urethane (meth) acrylate (A)>
[Production Example 1]
A flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube was charged with 400 parts by mass of polyether polyol (Sanixdiol PP-2000, number average molecular weight 2000, manufactured by Sanyo Chemical Industries, Ltd.). Next, while blowing nitrogen gas, the temperature in the system was raised to 60 ° C. and dissolved uniformly, 54 parts by mass of tolylene diisocyanate was added, the temperature was further raised to 100 ° C., and the temperature was kept for 6 hours. Then, the temperature was lowered to 90 ° C., and after stopping the blowing of nitrogen gas, 10 parts by mass of 2-hydroxyethyl acrylate and 0.5 parts by mass of hydroquinone monomethyl ether were added, and the temperature was kept for 7 hours. After confirming the disappearance of the isocyanate group in the reaction solution by IR measurement, the reaction was terminated to obtain urethane acrylate (TA37-228A) having a number average molecular weight of 11,000.

[Production Example 2]
In the same apparatus as in Production Example 1, 400 parts by mass of polyether polyol (Sanixdiol PP-2000, number average molecular weight 2000, manufactured by Sanyo Chemical Industries, Ltd.) was charged. Next, while blowing nitrogen gas, the temperature in the system was raised to 60 ° C. and dissolved uniformly, 59 parts by mass of tolylene diisocyanate was added, the temperature was further raised to 100 ° C., and the temperature was kept for 6 hours. Then, the temperature was lowered to 90 ° C., and after stopping the blowing of nitrogen gas, 16 parts by mass of 2-hydroxyethyl acrylate and 0.5 parts by mass of hydroquinone monomethyl ether were added, and the temperature was kept for 7 hours. After confirming the disappearance of the isocyanate group in the reaction solution by IR measurement, the reaction was terminated to obtain urethane acrylate (TA37-228B) having a number average molecular weight of 5000.

[Production Example 3]
In the same apparatus as in Production Example 1, 400 parts by mass of polyester polyol (Teslac 2462 (polyester polyol comprising methylpentanediol and adipic acid), number average molecular weight 2000, manufactured by Hitachi Chemical Polymer Co., Ltd.) was charged. Next, while blowing nitrogen gas, the temperature in the system was raised to 60 ° C. and dissolved uniformly, and then 54 parts by mass of isophorone diisocyanate was added, and the temperature was further raised to 100 ° C. and kept warm for 4 hours. Then, the temperature was lowered to 90 ° C., and after stopping the blowing of nitrogen gas, 10 parts by mass of 2-hydroxyethyl acrylate and 0.5 parts by mass of hydroquinone monomethyl ether were added, and the temperature was kept for 8 hours. After confirming the disappearance of the isocyanate group in the reaction solution by IR measurement, the reaction was terminated to obtain urethane acrylate (TA37-228C) having a number average molecular weight of 11,000.

[Production Example 4]
400 parts by mass of polyester polyol (Teslac 2477 (polyester polyol composed of ethylene glycol, hexanediol, adipic acid, and isophthalic acid), number average molecular weight 2000, manufactured by Hitachi Chemical Co., Ltd.) is charged in the same apparatus as in Production Example 1. It is. Next, while blowing nitrogen gas, the temperature in the system was raised to 60 ° C. and dissolved uniformly, and then 54 parts by mass of isophorone diisocyanate was added, and the temperature was further raised to 100 ° C. and kept warm for 4 hours. Then, the temperature was lowered to 90 ° C., and after stopping the blowing of nitrogen gas, 10 parts by mass of 2-hydroxyethyl acrylate and 0.5 parts by mass of hydroquinone monomethyl ether were added, and the temperature was kept for 8 hours. After confirming the disappearance of the isocyanate group in the reaction solution by IR measurement, the reaction was terminated to obtain urethane acrylate (TA37-228D) having a number average molecular weight of 11,000.

<Preparation of adhesive composition>
[Example 1]
35 parts by mass of TA37-228A as urethane (meth) acrylate (A);
As (meth) acrylic acid ester (B), 45 parts by mass of isobornyl acrylate (IBXA) (manufactured by Kyoeisha Chemical Co., Ltd.);
20 parts by mass of tetrahydrofurfuryl acrylate (THFA) (Biscoat # 150, manufactured by Osaka Organic Chemical Co., Ltd.) as (meth) acrylic acid ester (C);
3 parts by mass of 1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184 (IC184), manufactured by Ciba Japan Co., Ltd.) as the photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform adhesive composition (1).

[Example 2]
35 parts by mass of TA37-228A as urethane (meth) acrylate (A);
40 parts by mass of dicyclopentanyl acrylate (FA-513AS, manufactured by Hitachi Chemical Co., Ltd.) as the (meth) acrylic acid ester (B);
As (meth) acrylic acid ester (C), 25 parts by mass of THFA;
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform adhesive composition (2).

[Example 3]
35 parts by mass of TA37-228A as urethane (meth) acrylate (A);
As (meth) acrylic acid ester (B), 35 parts by mass of IBXA;
30 parts by mass of THFA as (meth) acrylic acid ester (C);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform adhesive composition (3).

[Example 4]
30 parts by mass of TA37-228A as urethane (meth) acrylate (A);
40 parts by mass of IBXA as the (meth) acrylic acid ester (B);
30 parts by mass of THFA as (meth) acrylic acid ester (C);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform adhesive composition (4).

[Example 5]
35 parts by mass of TA37-228B as urethane (meth) acrylate (A);
40 parts by mass of IBXA as the (meth) acrylic acid ester (B);
As (meth) acrylic acid ester (C), 25 parts by mass of THFA;
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform adhesive composition (5).

[Example 6]
30 parts by mass of TA37-228C as urethane (meth) acrylate (A);
As (meth) acrylic acid ester (B), 45 parts by mass of IBXA;
As (meth) acrylic acid ester (C), 25 parts by mass of THFA;
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform adhesive composition (6).

[Comparative Example 1]
30 parts by mass of TA37-228A as urethane (meth) acrylate (A);
70 parts by mass of IBXA as the (meth) acrylic acid ester (B);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform comparative adhesive composition (1).

[Comparative Example 2]
30 parts by mass of TA37-228A as urethane (meth) acrylate (A);
70 parts by weight of THFA as (meth) acrylic acid ester (C);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform comparative adhesive composition (2).

[Comparative Example 3]
30 parts by mass of TA37-228D having an aromatic ring;
40 parts by mass of IBXA as the (meth) acrylic acid ester (B);
30 parts by mass of THFA as (meth) acrylic acid ester (C);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform comparative adhesive composition (3).

[Comparative Example 4]
30 parts by mass of TA37-228A as urethane (meth) acrylate (A);
40 parts by mass of IBXA as the (meth) acrylic acid ester (B);
30 parts by mass of ortho-phenylphenol ethylene oxide (EO) modified acrylate (FA-302A, manufactured by Hitachi Chemical Co., Ltd.);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform comparative adhesive composition (4).

[Comparative Example 5]
30 parts by mass of TA37-228A as urethane (meth) acrylate (A);
40 parts by mass of IBXA as the (meth) acrylic acid ester (B);
30 parts by mass of phenoxyethyl acrylate (FA-310A, manufactured by Hitachi Chemical Co., Ltd.);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform comparative adhesive composition (5).

[Comparative Example 6]
30 parts by mass of TA37-228A as urethane (meth) acrylate (A);
40 parts by mass of IBXA as the (meth) acrylic acid ester (B);
30 parts by mass of 2-hydroxyethyl acrylate (AHEC) (light ester HOA, manufactured by Kyoeisha Chemical Co., Ltd.);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform comparative adhesive composition (6).

[Comparative Example 7]
30 parts by mass of TA37-228A as urethane (meth) acrylate (A);
30 parts by mass of THFA as (meth) acrylic acid ester (C);
40 parts by mass of 2-acryloyloxyethyl-phthalic acid (MPL) (HOA-MPL, manufactured by Kyoeisha Chemical Co., Ltd.);
3 parts by mass of IC184 as a photopolymerization initiator (D);
Was sufficiently heated and stirred at 60 ° C. to prepare a uniform comparative adhesive composition (7).

  The compositions of the adhesive compositions prepared in the above examples and comparative examples are shown in Table 1 below.

<Preparation of test piece>
The adhesive compositions and comparative adhesive compositions obtained in the above examples and comparative examples are evenly distributed on a polycarbonate (PC) film having a film thickness of 130 μm so that the film thickness of the adhesive composition is 15 μm. It apply | coated and the PC film was bonded together on this. Thereafter, the obtained laminate was irradiated with UV using a UV irradiation apparatus (ECS-401GX, manufactured by Eye Graphics Co., Ltd.) (lamp: 160 W / cm metal halide lamp (M04-L41), lamp output: 2 kW, conveyor speed. : 5 m / min, lamp height: 180 mm, integrated light quantity: 500 mJ / cm ² ), and the adhesive composition was cured to prepare a test piece.

<Heat resistance test>
The test piece produced above was put in a constant temperature tester at 85 ° C. and left for 1000 hours as a test piece after the heat resistance test.

<Moisture and heat resistance test>
The test piece prepared above was placed in a constant temperature and humidity tester at 65 ° C. and 95% RH (relative humidity) and left for 100 hours to obtain a test piece after the moisture and heat resistance test.

<Light resistance test>
The test piece prepared above was left as it was for 288 hours at 37 ° C. and 40% RH (relative humidity) using an ultraviolet auto fade meter (U48AU, manufactured by Suga Test Instruments Co., Ltd.). .

<Measurement of adhesive strength>
The test piece prepared above was cut into a width of 1 cm, a 180 ° peel test (speed: 10 mm / min) was performed, and the adhesive force was measured. The results are shown in Table 2 below.

<Measurement of optical properties>
About the test piece before and after the heat resistance test, the moist heat resistance test, or the light resistance test created above, the color difference ΔE ^* due to the lightness index L ^* and the color coordinates a ^* and b ^* of the color space having a perceptually almost uniform rate ^. Was measured using a minute formula color meter (SE-2000, manufactured by Nippon Denshoku Industries Co., Ltd.). The results are shown in Table 2 below.

  From the results in Table 2, it was shown that Examples 1 to 6 were excellent in the initial adhesive force, and the deterioration of the adhesive ability was small even after each durability test. Moreover, Examples 1-6 showed that the deterioration (coloring) of the optical characteristic after each durability test was also suppressed.

  On the other hand, Comparative Examples 1 and 2 using only either (meth) acrylic acid ester (B) or (meth) acrylic acid ester (C) had remarkably low adhesive strength. That is, from the results of Examples 1, 3 to 6 and Comparative Examples 1 and 2, (meth) acrylic acid ester (B) and (meth) acrylic acid ester (C) are low in adhesive strength by themselves, but by combining It was shown that remarkable adhesive force was developed. Moreover, it replaced with (meth) acrylic acid ester (B) or (meth) acrylic acid ester (C), and 4-7 which used other acrylic acid ester had remarkably low adhesive force. In addition, in Comparative Example 3 using a polyester polyol having an aromatic ring as a skeleton without using the urethane (meth) acrylate (A) of this embodiment, deterioration of optical properties was observed after each durability test.

Claims (5)

Urethane (meth) acrylate (A),
(Meth) acrylic acid ester (B) represented by the following chemical formula (1),
An active energy ray-curable adhesive composition comprising (meth) acrylic acid ester (C) represented by the following chemical formula (2);
The urethane (meth) acrylate (A) has at least one selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, and hydrogenated polybutadiene polyols having a terminal hydroxyl group and no aromatic ring as a skeleton. As a polyol (a1), an isocyanate compound (a2), and a (meth) acrylic acid ester (a3) having a hydroxyl group;

In the chemical formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a substituted or unsubstituted cyclic saturated hydrocarbon group;

In the chemical formula (2), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents a substituted or unsubstituted saturated heterocyclic group containing an oxygen atom. The content of the urethane (meth) acrylate (A) is 5 to 60% by mass with respect to the total mass of the adhesive composition, and the content of the (meth) acrylic acid ester (B) is 5 to 90%.
The active energy ray hardening-type adhesive composition of Claim 1 which is mass% and whose content of the said (meth) acrylic acid ester (C) is 5-80 mass%.   The active energy ray hardening-type adhesive composition of Claim 1 or 2 in which the frame | skeleton of the said urethane (meth) acrylate (A) contains at least 1 sort (s) selected from the group which consists of polyether polyol and polyester polyol. The active energy ray-curable adhesive composition according to claim 1, wherein R ² is an isobornyl group or a dicyclopentanyl group, and R ⁴ is a tetrahydrofurfuryl group. . The process of bonding a 1st base material and a 2nd base material through the mixture of the active energy ray hardening-type adhesive composition and photoinitiator of any one of Claims 1-4. When,
And then irradiating the mixture with active energy rays.