WO2019069872A1 - Uv-curable adhesive composition, cured product thereof, and method for manufacturing optical member employing uv-curable adhesive composition - Google Patents

Abstract

(1) A resin composition used to bond at least two optical substrates, which is an intramolecular hydrogen abstraction type photopolymerization initiator (A), a photopolymerizable oligomer (B), and a (meth) acrylate monomer ( C), the content of the solvent in the resin composition is 5% by weight or less, the weight average molecular weight of the photopolymerizable oligomer (B) is in the range of 7000 to 100000, and the cured product of the resin composition A UV-curable adhesive composition having a light transmittance of 85% or more in a wavelength range of 450 to 800 nm.

Description

UV-curable adhesive composition, cured product thereof and method for producing optical member using UV-curable adhesive composition

The present invention relates to a UV-curable adhesive composition for bonding at least two optical substrates, a cured product thereof, and a method for producing an optical member using the UV-curable adhesive composition.

In recent years, a display device in which a touch panel is attached to a display screen of a display device such as a liquid crystal display, a plasma display, an organic EL display, etc. to enable screen input has been widely used. In this touch panel, a glass plate or a resin film on which a transparent electrode is formed is attached facing each other with a slight gap, and if necessary, a transparent protective plate made of glass or resin on the touch surface Has a laminated structure.

There is a technique of using a double-sided pressure-sensitive adhesive sheet for bonding a glass plate or a film on which a transparent electrode is formed in a touch panel and a transparent protective plate made of glass or resin, or bonding a touch panel and a display unit. However, when the double-sided pressure-sensitive adhesive sheet is used, there is a problem that air bubbles are easily introduced. As a technique to replace the double-sided pressure-sensitive adhesive sheet, a technique of bonding with a flexible UV-curable adhesive composition has been proposed.

Further, in recent years, thinning of display devices such as smartphones and tablet PCs has progressed. In order to realize a thin display device, it is necessary to thin a display device such as a liquid crystal display or an organic EL display, a touch sensor, a glass plate for protection or a film. Various efforts have been made to reduce the thickness of each member, and a wide variety of materials have been used for the members. For example, although a PET film has been mainly used as a substrate for a film type touch panel sensor on which a transparent electrode is formed, there are cases in which a cycloolefin polymer, a transparent polyimide film or the like is used at present. Depending on the material of the optical base material to be bonded, the conventional adhesive causes poor adhesion to the base material, insufficient adhesion, and deterioration of the optical base material, causing a crack in the base material. There is.

In addition, it is also required to reduce the thickness of the adhesive layer as the thickness of the optical base decreases. In order to make the film thickness of the adhesive layer thin, it is necessary to apply the adhesive to the substrate with a thin film thickness. Adhesives for pasting together optical members are often those with high viscosity such as several thousand mPa · s or more at room temperature, and when applied with a thin film thickness, repelling and uneven coating may occur. There is also a problem that the coating method is also limited.
In order to apply the adhesive with a thin film thickness while supporting various application methods, it is effective to reduce the viscosity of the adhesive composition. As a general method for lowering the viscosity of the adhesive, a method of diluting with a solvent may be mentioned. However, when the adhesive or the like contains a solvent or the like, air bubbles occur when the optical substrates are attached to each other. It will cause peeling.

As a method for lowering the viscosity without using a solvent, Patent Document 1 mentions a method of lowering the viscosity of the adhesive composition by diluting with a reactive monomer, but the reactivity There is no mention at all about the problem that occurs when the viscosity is reduced by dilution with a monomer. With the prior art alone, as the content of the reactive monomer in the composition increases, it becomes difficult to achieve both flexibility and curability. When the flexibility is increased, the curability is deteriorated, and when the curability is improved, the flexibility and the adhesiveness are reduced. If the flexibility or adhesion is low, peeling may occur due to external stress, deformation of the optical substrate, thermal expansion or the like, and if the curability is poor, mass productivity may be reduced.

Japanese Patent No. 5563483

INDUSTRIAL APPLICABILITY The present invention is an ultraviolet curable resin which has less damage to an optical substrate, is capable of bonding at least two optical substrates even in a thin film thickness, and has good curability, flexibility, and adhesiveness. An object of the present invention is to provide an adhesive composition, a cured product thereof, and a method for producing an optical member using a UV-curable adhesive composition.

（式中、Ｘはアクリロイル基、又はメタクリロイル基を示し、Ｒ_１は炭素数８～１８個のアルキル基を表す）
で表される単官能（メタ）アクリレートモノマー（Ｃ－１）を含有する、（１）～（５）のいずれかに記載の紫外線硬化型接着剤組成物。
（７）（メタ）アクリレートモノマー（Ｃ）として、脂環またはヘテロ環を有する単官能（メタ）アクリレートモノマー（Ｃ－２）を含有する、（１）～（６）のいずれかに記載の紫外線硬化型接着剤組成物。
（８）前記硬化物の２５℃における破断点伸度が２００％以上である、（１）～（７）のいずれかに記載の紫外線硬化型接着剤組成物。
（９）前記光学基材が、ガラス基板、透明樹脂基板、透明電極が形成してあるガラス基板、透明基板に透明電極が形成してあるガラス基板またはフィルムが貼り合わされた基板、液晶表示ユニット、プラズマ表示ユニット、及び有機ＥＬ表示ユニットからなる群から選ばれる１種以上の光学基材である、（１）～（８）のいずれかに記載の紫外線硬化型接着剤組成物。
（１０）タッチパネル用紫外線硬化型接着剤組成物であることを特徴とする、（１）～（９）のいずれかに記載の紫外線硬化型接着剤組成物。
（１１）（１）～（１０）のいずれかに記載の紫外線硬化型接着剤組成物に活性エネルギー線を照射して得られる硬化物。
（１２）下記工程１～２を有する少なくとも２つの光学基材が貼り合わされた光学部材の製造方法、
（工程１）少なくとも１つの光学基材に対して、（１）～（１０）のいずれかに記載の紫外線硬化型接着剤組成物を塗布して、塗布層を形成し、該塗布層に紫外線を照射することにより硬化物層を有する光学基材を得る工程
（工程２）工程１で得られた光学基材の硬化物層に対して、他の光学基材を貼り合わせるか、又は、工程１により得られた他の光学基材の硬化物層を貼り合わせる工程。 The present inventors completed the present invention as a result of earnest research in order to solve the above-mentioned subject. That is, the present invention relates to the following (1) to (12).
(1) A resin composition used to bond at least two optical substrates, which is an intramolecular hydrogen abstraction type photopolymerization initiator (A), a photopolymerizable oligomer (B), and a (meth) acrylate monomer ( C), the content of the solvent in the resin composition is 5% by weight or less, the weight average molecular weight of the photopolymerizable oligomer (B) is in the range of 7000 to 100000, and the cured product of the resin composition A UV-curable adhesive composition having a light transmittance of 85% or more in a wavelength range of 450 to 800 nm.
(2) The photopolymerizable oligomer (B) has at least one skeleton selected from the group consisting of urethane (meth) acrylates, or polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene and hydrogenated polyisoprene (meta ) The ultraviolet-curable adhesive composition according to (1), which is an acrylate.
(3) The photopolymerizable oligomer (B) is a urethane (meth) acrylate having at least one skeleton selected from the group consisting of polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene and hydrogenated polyisoprene ( 1) or the ultraviolet curable adhesive composition as described in (2).
(4) The ultraviolet-curable adhesive composition according to any one of (1) to (3), which has a viscosity of 1 to 300 mPa · s at 25 ° C.
(5) The ultraviolet-curable adhesive composition according to any one of (1) to (3), which has a viscosity of 1 to 100 mPa · s at 25 ° C.
(6) The following formula (1) as (meth) acrylate monomer (C)

(Wherein, X represents an acryloyl group or a methacryloyl group, and R ₁ represents an alkyl group having 8 to 18 carbon atoms)
The ultraviolet curable adhesive composition according to any one of (1) to (5), comprising the monofunctional (meth) acrylate monomer (C-1) represented by
(7) The ultraviolet ray according to any one of (1) to (6), containing a monofunctional (meth) acrylate monomer (C-2) having an alicyclic or heterocyclic ring as the (meth) acrylate monomer (C) Curable adhesive composition.
(8) The ultraviolet-curable adhesive composition according to any one of (1) to (7), wherein the elongation at break of the cured product at 25 ° C. is 200% or more.
(9) A glass substrate, a transparent resin substrate, a glass substrate on which a transparent electrode is formed, a substrate in which a glass substrate or a film on which a transparent electrode is formed is bonded to a transparent substrate, the liquid crystal display unit The ultraviolet-curable adhesive composition according to any one of (1) to (8), which is at least one optical substrate selected from the group consisting of a plasma display unit and an organic EL display unit.
(10) The ultraviolet curable adhesive composition according to any one of (1) to (9), which is an ultraviolet curable adhesive composition for a touch panel.
(11) A cured product obtained by irradiating the ultraviolet curable adhesive composition according to any one of (1) to (10) with an active energy ray.
(12) A method of producing an optical member in which at least two optical substrates having the following steps 1 to 2 are bonded,
(Step 1) A UV curable adhesive composition according to any one of (1) to (10) is applied to at least one optical substrate to form a coating layer, and UV light is applied to the coating layer. Step of obtaining an optical substrate having a cured product layer by irradiating (step 2) bonding the other optical substrate to the cured product layer of the optical substrate obtained in step 1 or A step of bonding the cured product layers of the other optical substrates obtained in 1.

According to the present invention, it is possible to bond at least two optical substrates with a thin film thickness with less damage to the optical substrate, and further to use ultraviolet light with good curability, flexibility, and adhesiveness. It is possible to provide a curable adhesive composition, a cured product thereof, and a method for producing an optical member using an ultraviolet curable adhesive composition.

It is process drawing which shows 1st Embodiment of the manufacturing method of this invention. It is process drawing which shows 2nd Embodiment of the manufacturing method of this invention. It is process drawing which shows 3rd Embodiment of the manufacturing method of this invention. It is the schematic of the optical member obtained by this invention.

First, the ultraviolet curable adhesive composition of the present invention will be described.
The ultraviolet-curable adhesive composition of the present invention is a resin composition used to bond at least two optical substrates together, and includes an intramolecular hydrogen abstraction type photopolymerization initiator (A) and a photopolymerizable oligomer (B). And a (meth) acrylate monomer (C), the content of the solvent in the resin composition is 5% by weight (wt%) or less, and the weight average molecular weight of the photopolymerizable oligomer (B) is 7,000 to 100,000. The light transmittance of the cured product of the resin composition in the wavelength range of 450 to 800 nm is 85% or more. Moreover, the other component which can be added to the ultraviolet curable adhesive composition used for an optical member as an arbitrary component can be included.

In addition, "it can be added to the ultraviolet curable adhesive composition used for an optical member" means that the additive which reduces the transparency of hardened | cured material to the grade which can not be used for an optical member is not contained.

In addition, the term "(meth) acrylate" is a term referring to either or both of acrylate and methacrylate. Moreover, the term "(meth) acryloyl group" described below is a term that refers to either or both of an acryloyl group and a methacryloyl group. For example, the term "octyl (meth) acrylate" refers to either or both of octyl acrylate and octyl methacrylate.

When a sheet of a cured product having a thickness of 200 μm after curing is produced with the UV-curable adhesive composition of the present invention, a preferred average transmittance of the sheet in the wavelength region of 450 to 800 nm is It is at least 85% or more, more preferably 90% or more.
The composition ratio of the ultraviolet-curable adhesive composition is preferably 0.1 to 5% by weight of the intramolecular hydrogen abstraction type photopolymerization initiator (A) and 5 to 50% by weight of the photopolymerizable oligomer (B). %, (Meth) acrylate monomer (C) is 20 to 94% by weight, and the other components are the balance.

The intramolecular hydrogen abstraction type photopolymerization initiator (A) in the ultraviolet ray curable adhesive composition of the present invention is not particularly limited, and any one which is generally sold can be used. By using the intramolecular hydrogen abstraction type photopolymerization initiator, the surface curability can be improved and film formation can be easily performed. For this reason, it is possible to form a cured film predominantly even in a thin film or in a resin having poor curability. Even if the hydrogen abstraction initiator is not an intramolecular hydrogen abstraction initiator, the curability and adhesion are inferior, but if it is an intramolecular hydrogen abstraction initiator, it exhibits excellent functions in both curability and adhesiveness. Can.

The intramolecular hydrogen-abstraction photopolymerization initiator (A) contained in the UV-curable adhesive composition of the present invention is not particularly limited, and, for example, methyl benzoyl formate (IRGACURE MBF; manufactured by BASF), oxy Oxyphenyl photopolymerization, such as a mixture of phenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid 2- (2-hydroxy-ethoxy) ethyl ester (IRGACURE 754; made by BASF) An initiator etc. are mentioned and you may use together 2 or more types as needed.

The photopolymerization initiator contained in the ultraviolet-curable adhesive composition of the present invention may contain a photopolymerization initiator other than the intramolecular hydrogen abstraction type photopolymerization initiator (A), and the intramolecular hydrogen abstraction is The photopolymerization initiators other than the photopolymerization initiator (A) are not particularly limited, and, for example, 2,4,6-trimethyl benzoyl diphenyl phosphine oxide, 2,4,6-trimethyl benzoyl phenyl ethoxy phosphine oxide Bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide, bis (2,6-dimethoxy benzoyl) -2,4,4-trimethyl-pentyl phosphine oxide, 1-hydroxycyclohexyl phenyl ketone (IRGACURE 184; manufactured by BASF), 2-hydroxy-2-methyl- [4- (1-methyl) Nyl) phenyl] propanol oligomer (Esacure ONE; made by Lambarty), 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (Irgacure 2959; BASF Available), 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one (IRGACURE 127; manufactured by BASF) 2, 2-Dimethoxy-2-phenylacetophenone (IRGACURE 651; manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur 1173; manufactured by BASF), 2-methyl-1 -[4- (Methylthio) phenyl] -2-morpholinopropan-1-one (IRGACURE-907 BASF), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-chlorothioxanthone, 2,4-dimethyl thioxanthone, 2,4-diisopropyl thioxanthone, isopropyl thioxanthone, etc. Can be mentioned.
Among them, 2,4,6-trimethylbenzoyldiphenyl phosphine oxide, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane from the viewpoint of curability and transparency. It is preferred to use -1- on.

In the ultraviolet-curable adhesive composition of the present invention, one or two photopolymerization initiators other than the intramolecular hydrogen abstraction type photopolymerization initiator (A) and the intramolecular hydrogen abstraction type photopolymerization initiator (A) are used. The species or more may be mixed and used in any proportion. The weight ratio of the intramolecular hydrogen abstraction type photopolymerization initiator (A) in the ultraviolet-curable adhesive composition of the present invention is usually 0.1 to 5% by weight, preferably 0.3 to 3% by weight. If it is more than 5% by weight, the transparency of the cured resin layer may be deteriorated. If the amount is less than 0.1% by weight, curing may be poor.
Here, when using photoinitiators other than an intramolecular hydrogen abstraction type photoinitiator (A), it is preferable to use an acyl phosphine oxide compound together. As the acyl phosphine oxide compound, for example, 2,4,6-trimethyl benzoyl diphenyl phosphine oxide, 2,4,6- trimethyl benzoyl phenyl ethoxy phosphine oxide, bis (2,4,6-trimethyl benzoyl) -phenyl Phosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl phosphine oxide, etc. may be mentioned. The acyl phosphine oxide compound is preferably used in combination since it can absorb a wide range of wavelengths because the light absorption region is different from the intramolecular hydrogen abstraction type photopolymerization initiator.
When used in combination, the weight ratio of the intramolecular hydrogen abstraction type photopolymerization initiator (A): acyl phosphine oxide compound is preferably 20: 1 to 1: 5, and more preferably 10: 1 to 1: 1.

The photopolymerizable oligomer (B) in the ultraviolet curable adhesive composition of the present invention is not particularly limited as long as the weight average molecular weight is in the range of 7,000 to 100,000, but urethane (meth) acrylate, or polypropylene, polybutadiene, water It is preferable to use a (meth) acrylate having at least one or more skeleton selected from the group consisting of added polybutadiene, polyisoprene and hydrogenated polyisoprene. Among them, urethane (meth) acrylate is preferable from the viewpoint of adhesive strength, and urethane (meth) having at least one or more skeleton selected from the group consisting of polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene and hydrogenated polyisoprene ) Acrylate is more preferred.
Here, the weight average molecular weight of the photopolymerizable oligomer (B) is preferably 7,000 to 100,000, more preferably 9,000 to 80,000, and particularly preferably 11,000 to 70000.

The weight average molecular weight can be measured using GPC (gel permeation chromatography) under the following conditions.
Model: TOSOH HLC-8320GPC
Column: SuperMultipore HZ-M
Eluent: THF (tetrahydrofuran); 0.35 ml / min, 40 ° C
Detector: RI (differential refractometer)
Molecular weight standard: polystyrene

In the present invention, the content ratio of the photopolymerizable oligomer (B) is usually 5 to 50% by weight, preferably 5 to 30% by weight, and more preferably 5 to 25% by weight in the ultraviolet-curable adhesive composition. 5 to 20% by weight is particularly preferred.
The weight ratio of the photopolymerizable oligomer (B) to the (meth) acrylate monomer (C) is preferably 1: 1 to 1:25, more preferably 4: 6 to 1:20, 3: 7 To 1:20 is more preferable, and 1: 4 to 1:20 is particularly preferable.
By setting the photopolymerizable oligomer (B) and the (meth) acrylate monomer (C) in the range of the above ratio, it is possible to obtain a preferable cured product having a high elongation of the cured film while securing the curing property.

The urethane (meth) acrylate is obtained, for example, by reacting a polyhydric alcohol, a polyisocyanate and a hydroxyl group-containing (meth) acrylate.

Examples of polyhydric alcohols include polybutadiene glycol, hydrogenated polybutadiene glycol, polyisoprene glycol, hydrogenated polyisoprene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, ethylene glycol, propylene glycol, 1,4 Alkylene glycol having 1 to 10 carbon atoms such as butanediol and 1,6-hexanediol, triol such as trimethylolpropane and pentaerythritol, tricyclodecane dimethylol and cyclic skeleton such as bis- [hydroxymethyl] -cyclohexane And the polyhydric alcohols and polybasic acids (eg, succinic acid, phthalic acid, hexahydrophthalic anhydride, terephthalic acid, adipic acid, azelaic acid, tetrahydrophthalic anhydride, etc.) Polyester polyol obtained by reaction, caprolactone alcohol obtained by reaction of polyhydric alcohol and ε-caprolactone, polycarbonate polyol (eg polycarbonate diol obtained by reaction of 1,6-hexanediol and diphenyl carbonate, etc.) or polyether polyol (For example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, ethylene oxide modified bisphenol A and the like) and the like can be mentioned. From the viewpoint of adhesive strength and moisture resistance, as the above-mentioned polyhydric alcohol, polypropylene glycol, polybutadiene glycol, hydrogenated polybutadiene glycol, polyisoprene glycol, hydrogenated polyisoprene glycol are preferable, and from the viewpoint of transparency and flexibility, weight average molecular weight Particularly preferred are polypropylene glycols of at least 2000, hydrogenated polybutadiene glycols and hydrogenated polyisoprene glycols. Hydrogenated polybutadiene glycol or polypropylene glycol is preferable from the viewpoint of color-changing properties such as heat-resistant colorability and compatibility. On the other hand, polypropylene glycol is preferable from the viewpoint of compatibility with other components. Although the upper limit of the weight average molecular weight at this time is not particularly limited, it is preferably 10000 or less, more preferably 5000 or less. Moreover, you may use together 2 or more types of polyhydric alcohol as needed.

Examples of the polyisocyanate include isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and dicyclopentanyl isocyanate. Among them, isophorone diisocyanate is preferable from the viewpoint of toughness.

Moreover, as the hydroxyl group-containing (meth) acrylate, for example, hydroxy C2 to C4 alkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, etc., dimethylol cyclohexyl mono ( Meta) acrylate, hydroxycaprolactone (meth) acrylate, hydroxyl group-terminated polyalkylene glycol (meth) acrylate and the like can be used.

The reaction for obtaining the urethane (meth) acrylate is performed, for example, as follows. That is, polyisocyanate is mixed with polyhydric alcohol per equivalent of hydroxyl group so that the isocyanate group is preferably 1.1 to 2.0 equivalents, more preferably 1.1 to 1.5 equivalents, and the reaction temperature is The reaction is preferably performed at 70 to 90 ° C. to synthesize a urethane oligomer. Next, a hydroxy (meth) acrylate compound is mixed so that the hydroxyl group is preferably 1 to 1.5 equivalents per equivalent of isocyanate groups of the urethane oligomer, and the reaction is carried out at 70 to 90 ° C. ) Acrylates can be obtained.

The weight average molecular weight of the urethane (meth) acrylate is preferably about 7,000 to 100,000, more preferably 9,000 to 80000, and still more preferably 11,000 to 70000. If the weight average molecular weight is less than 7,000, the flexibility may be impaired, and if the weight average molecular weight is greater than 100,000, the curability may be poor. The molecular weight distribution (weight-average molecular weight (Mw) / number-average molecular weight (Mn)) is preferably 1.5 or more.

In the ultraviolet curable adhesive composition of the present invention, the urethane (meth) acrylate can be used by mixing one or two or more in any ratio. The weight ratio of the urethane (meth) acrylate in the ultraviolet curable adhesive composition of the present invention is usually 5 to 50% by weight, preferably 5 to 30% by weight, more preferably 5 to 25% by weight, 20% by weight is particularly preferred.

The (meth) acrylate having a polybutadiene backbone has a (meth) acryloyl group at the terminal or side chain of the polybutadiene molecule. A (meth) acrylate having a polybutadiene backbone can be obtained as "BAC-45" (manufactured by Osaka Organic Chemical Industry Co., Ltd.). The weight average molecular weight of the (meth) acrylate having a polybutadiene skeleton is preferably 3,000 to 50,000, and more preferably 5,000 to 30,000.
The weight ratio of the (meth) acrylate having a polybutadiene skeleton in the ultraviolet curable adhesive composition of the present invention is usually 5 to 50% by weight, preferably 5 to 30% by weight, more preferably 5 to 25% by weight. Preferably, 5 to 20% by weight is particularly preferred.

The (meth) acrylate having a polyisoprene backbone has a (meth) acryloyl group at the terminal or side chain of the polyisoprene molecule. A (meth) acrylate having a polyisoprene backbone can be obtained as "UC-203" (manufactured by Kuraray Co., Ltd.). The weight average molecular weight of the (meth) acrylate having a polyisoprene skeleton is preferably 7,000 to 100,000, and more preferably about 20,000 to 50,000.
The weight ratio of the (meth) acrylate having a polyisoprene skeleton in the ultraviolet curable adhesive composition of the present invention is usually 5 to 50% by weight, preferably 5 to 30% by weight, more preferably 5 to 25% by weight. Preferably, 5 to 20% by weight is particularly preferred.

The UV curable adhesive composition of the present invention may contain a photopolymerizable oligomer having a weight average molecular weight outside the range of 7,000 to 100,000, as long as the properties of the present invention are not impaired.

The (meth) acrylate monomer (C) contained in the ultraviolet-curable adhesive composition of the present invention is not particularly limited, but preferably has one (meth) acryloyl group in the molecule (meth) Acrylate can be suitably used. Here, the (meth) acrylate monomer (C) is at least one skeleton selected from the group consisting of urethane (meth) acrylate, or polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene. The (meth) acrylate which remove | eliminated the (meth) acrylate which has is shown.

Specific examples of (meth) acrylate monomers having one (meth) acryloyl group in the molecule include octyl (meth) acrylate, isooctyl (meth) acrylate, isoamyl (meth) acrylate, lauryl (meth) acrylate and isodecyl (Meth) acrylate, stearyl (meth) acrylate, cetyl (meth) acrylate, isomyristyl (meth) acrylate, isostearyl (meth) acrylate, tridecyl (meth) acrylate, etc. having an alkyl group having 5 to 25 carbon atoms (meth ) Acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, acryloyl morpholine, cyclic trimethylol propane formal acrylate, phenyl glycidyl (meth) acrylate, tri Clodecane (meth) acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 1-adamantyl acrylate, 2-methyl-2-adamantyl acrylate, A cyclic skeleton such as 2-ethyl-2-adamantyl acrylate, 1-adamantyl methacrylate, polypropylene oxide modified nonylphenyl (meth) acrylate, ethoxylated o-phenylphenol acrylate, dicyclopentadiene oxyethyl (meth) acrylate, etc. ) Acrylate, (meth) acrylate having a C 2-7 alkyl group having a hydroxyl group, ethoxydiethylene glycol (meth) acrylate, poly Polyalkylene glycol (meth) acrylates such as ropylene glycol (meth) acrylate and polypropylene oxide modified nonylphenyl (meth) acrylate, ethylene oxide modified phenoxated phosphoric acid (meth) acrylate, ethylene oxide modified butylated phosphoric acid (meth) acrylate, ethylene oxide modified The octyl oxylated phosphoric acid (meth) acrylate, caprolactone modified tetraflufuryl (meth) acrylate, etc. can be mentioned.

Among them, from the viewpoint of flexibility and dilutability, the following formula (1)

Wherein the monofunctional (meth) acrylate monomer (C-1) represented by (wherein X represents an acryloyl group or a methacryloyl group, and R ₁ represents an alkyl group having 8 to 18 carbon atoms) Is preferred. Furthermore, from the viewpoint of volatility and reactivity, normal octyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate and isostearyl (meth) acrylate are more preferable.

Further, from the viewpoint of adhesiveness, it is preferable to contain a monofunctional (meth) acrylate monomer (C-2) having an alicyclic or heterocyclic ring. Specific examples of the monofunctional (meth) acrylate monomer (C-2) having an alicyclic or heterocyclic ring include tetrahydrofurfuryl (meth) acrylate, acryloyl morpholine, dicyclopentenyl (meth) acrylate, cyclic trimethylolpropane Formal acrylate, dicyclopentenyl oxyethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 1-adamantyl acrylate, 2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate 1-adamantyl methacrylate, dicyclopentadiene oxyethyl (meth) acrylate and the like. Among them, acryloyl morpholine, dicyclopentanyl (meth) acrylate and isobornyl (meth) acrylate are more preferable from the viewpoint of compatibility with other materials, and acryloyl morpholine and dicyclopentanyl (meth) acrylate are preferable from the viewpoint of adhesiveness. More preferable.

Moreover, it is preferable to contain the (meth) acrylate monomer which has a hydroxyl group as a (meth) acrylate monomer (C) from a viewpoint of the tolerance of high temperature and / or high humidity.
As a (meth) acrylate monomer which has a hydroxyl group, hydroxybutyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate etc. can be mentioned.

Here, the (meth) acrylate monomer (C-1) represented by the above formula (1), the monofunctional (meth) acrylate monomer (C-2) having an alicyclic or heterocyclic ring, and (meth) having a hydroxyl group It is preferable to contain two or more kinds of different classifications selected from the group consisting of acrylates. Moreover, it is more preferable to contain three or more types of different classifications. When two or more kinds are contained, any (meth) acrylate monomer is preferably contained in an amount of 4 to 90% by weight, more preferably 4 to 80% by weight, in the ultraviolet-curable adhesive composition.
In addition, in the case of containing two or more kinds, (meth) acrylate monomer represented by the above-mentioned formula (1): (monofunctional (meth) acrylate monomer having an alicyclic or heterocyclic ring + having a hydroxyl group (meth The weight ratio of (a) acrylate monomer) is preferably 1: 2 to 20: 1, and more preferably 1: 1 to 10: 1.

Furthermore, from the viewpoint of curability, the (meth) acrylate monomer (C) is preferably an acrylate monomer.

The ultraviolet curable adhesive composition of the present invention contains (meth) acrylates other than (meth) acrylates having one (meth) acryloyl group in the molecule within the range that the characteristics of the present invention are not impaired. Can. For example, tricyclodecane dimethylol di (meth) acrylate, dioxane glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, alkylene oxide modified bisphenol A type di (meth) acrylate Trimethylol C2 to C10 alkanes such as caprolactone modified hydroxypivalate neopentyl glycol di (meth) acrylate and ethylene oxide modified phosphoric acid di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethyloloctane tri (meth) acrylate, etc. Tri (meth) acrylate, trimethylolpropane polyethoxy tri (meth) acrylate, trimethylolpropane polypropoxy tri ( Ta) Trimethylol C2-C10 alkanepolyalkoxytri (meth) acrylates such as acrylate, trimethylolpropane polyethoxypolypropoxy tri (meth) acrylate, tris [(meth) acroyloxyethyl] isocyanurate, pentaerythritol tri ( Alkylene oxide modified trimethylolpropane tri (meth) acrylate pentaerythritol polyethoxytetra (meth) acrylate, such as meta) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, etc. Pentaerythritol polypropoxy tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrime Trimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.
In the present invention, when used in combination, it is preferable to use a mono- or difunctional (meth) acrylate in order not to impair the flexibility.

In the ultraviolet curable adhesive composition of the present invention, these (meth) acrylate monomer (C) components can be used by mixing one kind or two or more kinds in an arbitrary ratio. The proportion by weight of the (meth) acrylate monomer (C) in the ultraviolet-curable adhesive composition of the present invention is usually 20 to 95% by weight, preferably 25 to 95% by weight, more preferably 30 to 95% by weight. When the amount is less than 20% by weight, the curability is poor, and when the amount is more than 95% by weight, the shrinkage is large.

Epoxy (meth) acrylate can be used for the ultraviolet curable adhesive composition of the present invention as long as the properties of the present invention are not impaired. Epoxy (meth) acrylates have the function of improving the curability and improving the hardness and curing speed of the cured product. Further, as the epoxy (meth) acrylate, any epoxy (meth) acrylate obtained by reacting a glycidyl ether type epoxy compound and (meth) acrylic acid can be used, but preferably used epoxy (meth) acrylate As a glycidyl ether type epoxy compound for obtaining, diglycidyl ether of bisphenol A or its alkylene oxide adduct, diglycidyl ether of bisphenol F or its alkylene oxide adduct, diglycidyl of hydrogenated bisphenol A or its alkylene oxide adduct Ether, diglycidyl ether of hydrogenated bisphenol F or its alkylene oxide adduct, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether Neopentyl glycol diglycidyl ether, butanediol diglycidyl ether hexanediol diglycidyl ether to, cyclohexanedimethanol diglycidyl ether, and polypropylene glycol diglycidyl ether.

The epoxy (meth) acrylate is obtained by reacting these glycidyl ether type epoxy compounds with (meth) acrylic acid under the following conditions.

(Meth) acrylic acid is reacted in a ratio of 0.9 to 1.5 mol, more preferably 0.95 to 1.1 mol, per equivalent of the epoxy group of the glycidyl ether type epoxy compound. The reaction temperature is preferably 80 to 120 ° C., and the reaction time is about 10 to 35 hours. In order to accelerate the reaction, it is preferable to use a catalyst such as triphenylphosphine, TAP, triethanolamine, tetraethylammonium chloride and the like. In addition, for example, paramethoxyphenol, methylhydroquinone and the like can be used as a polymerization inhibitor to prevent polymerization during the reaction.

The epoxy (meth) acrylate which can be suitably used in the present invention is bisphenol A epoxy (meth) acrylate obtained from a bisphenol A type epoxy compound. The weight average molecular weight of the epoxy (meth) acrylate is preferably 500 to 10,000.
The proportion by weight of the epoxy (meth) acrylate in the ultraviolet-curable adhesive composition of the present invention is usually 1 to 20% by weight, preferably 5 to 15% by weight.

The UV-curable adhesive composition of the present invention can contain, as other components, a softening component described later, an additive described later, and the like. The content ratio of the other components to the total amount of the ultraviolet-curable adhesive composition of the present invention is the remainder obtained by reducing the total amount of the components (A), (B) and (C) from the total amount. , It is a ratio to the total amount. Specifically, the content ratio of the other components with respect to the total amount of the ultraviolet curable adhesive composition of the present invention is preferably 5 to 75% by weight, more preferably 15 to 75% by weight, particularly preferably 35 It is about 65% by weight.
In addition, a softener is a compound which does not have a (meth) acryloyl group here.

Furthermore, amines and the like that can be a photopolymerization initiation aid can be used in combination with the above-mentioned photopolymerization initiator. Examples of amines which can be used include benzoic acid 2-dimethylaminoethyl ester, dimethylaminoacetophenone, p-dimethylaminobenzoic acid ethyl ester and p-dimethylaminobenzoic acid isoamyl ester. In the case of using a photopolymerization initiation aid such as the amines, the content ratio in the ultraviolet curable adhesive composition of the present invention is usually 0.005 to 5% by weight, preferably 0.01 to 3% by weight. .

A softening component can be used in the ultraviolet-curable adhesive composition of the present invention as required. Specific examples of the softening component that can be used include polymers compatible with the composition, oligomers, phthalic esters, phosphoric esters, glycol esters, citric esters, aliphatic dibasic esters, fatty acids Esters, epoxy plasticizers, castor oils, terpene resins, hydrogenated terpene resins, rosin resins, hydrogenated rosin resins, liquid terpenes and the like can be mentioned. Examples of the above-mentioned oligomers and polymers include oligomers or polymers having a polyisoprene backbone, a hydrogenated polyisoprene backbone, a polybutadiene backbone, a hydrogenated polybutadiene backbone or a xylene backbone, and esters thereof, polybutenes and the like. From the viewpoint of transparency, hydrogenated terpene resins, hydrogenated polyisoprene, hydrogenated polybutadiene, polybutene, and liquid terpenes are preferable. Furthermore, from the viewpoint of adhesion strength and compatibility with other materials, hydrogenated terpene resins containing a hydroxyl group at the end or side chain, hydrogenated polyisoprene containing a hydroxyl group at the end or side chain, or a hydroxyl group Alternatively, hydroxyl group-containing polymers such as hydrogenated polybutadiene, which are contained in side chains, hydrogenated rosin resins, and liquid terpene resins are particularly preferable.

The proportion by weight of such a softening component in the UV-curable adhesive composition is usually 5 to 40% by weight, preferably 10 to 35% by weight when a solid softening component is used. When a liquid softening component is used, it is generally 10 to 70% by weight, preferably 20 to 60% by weight.
The total proportion by weight of the solid and liquid softening components in the UV-curable adhesive composition is usually 5 to 90% by weight, preferably 10 to 75% by weight.

In the UV curable adhesive composition of the present invention, if necessary, an antioxidant, a thixotropy imparting agent, an antifoaming agent, a surface tension regulator, a silane coupling agent, a polymerization inhibitor, a leveling agent, an antistatic agent Additives such as surface lubricants, optical brighteners, light stabilizers (for example, hindered amine compounds etc.) may be added.
In the present invention, the amount of the solvent is 0% by weight or more and 5% by weight or less in the ultraviolet curable adhesive composition. This is because, if the solvent is contained in a large amount, film formation becomes difficult, and in addition, a concave portion is generated in the cured product and the curability is adversely affected. Here, 0 weight% or more and 3 weight% or less are preferable in a ultraviolet curable adhesive composition, and 0 weight% or more and 2 weight% or less are more preferable.

Specific examples of the antioxidant include, for example, BHT, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine , Pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylene bis [3- (3,5-di-t-butyl- 4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3-t -Butyl-5-methyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N-hexamethylene bis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t) -Butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, octylated diphenylamine, 2,4-bis [(octylthio) methyl-O-cresol , Isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], dibutylhydroxytoluene and the like.

Specific examples of the silane coupling agent include, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy Cyclohexyl) ethyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3- Aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, -Silane coupling agents such as -chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, etc .; isopropyl (N-ethylaminoethylamino) titanate, isopropyl triisostearoyl titanate, titanium di (dioctyl pyrophosphate) oxyacetate, Titanium-based coupling agents such as tetraisopropyl di (dioctyl phosphite) titanate, neoalkoxy tri (p-N- (β-aminoethyl) aminophenyl) titanate, etc .; Zr-acetylacetonate, Zr-methacrylate, Zr-propionate, Neoalkoxy zirconate, neoalkoxy tris neodecanoyl zirconate, neoalkoxy tris (dodecanoyl) benzenesulfonyl zirconate, neoalkoxy tris Ethylene-aminoethyl) zirconate, neoalkoxy tris (m-aminophenyl) zirconate, ammonium zirconium carbonate, Al- acetylacetonate, Al- methacrylate, zirconium or the like Al- propionate, or aluminum coupling agent, and the like.

As specific examples of the polymerization inhibitor, paramethoxyphenol, methylhydroquinone and the like can be mentioned.

Specific examples of the light stabilizer include, for example, 1,2,2,6,6-pentamethyl-4-piperidyl alcohol, 2,2,6,6-tetramethyl-4-piperidyl alcohol, 1,2,2, 6,6-pentamethyl-4-piperidyl (meth) acrylate (Adeka Co., Ltd. LA-82), tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3, 4-butanetetracarboxylate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, 1,2,3,4-butanetetracarboxylic acid And 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5.5 ] Unde Mixed esters with decane, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate decanedioate, bis (1-undecanoxy-2,2,6,6-tetramethylpiperidine-4-) ), Carbonate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6, 6 6-Pentamethyl-4-piperidyl) sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) ) Propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine, 1,1 2,2,6,6-pentamethyl-4-piperidinyl-methacrylate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) [[3,5-bis (1,1-dimethylethyl)] -4-Hydroxyphenyl] methyl] butyl malonate, bis (2,2,6,6-tetramethyl-1 (octyloxy) -4-piperidinyl) ester of decanedioic acid, 1,1-dimethylethyl hydroperoxide and octane Of N, N ′, N ′ ′, N ′ ′ ′-tetrakis- (4,6-bis- (butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) ) Amino) -Triazin-2-yl) -4,7-diazadecane-1,10-diamine, dibutylamine · 1,3,5-triazine · N, N′-bis (2,2,6,6-tetra Methyl Polycondensate of 4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [[6- (1,1,3,3- Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6 -Tetramethyl-4-piperidyl) imino]], Polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, 2,2,4,4-tetramethyl- 20-(. Beta.-lauryloxycarbonyl) ethyl-7-oxa-3,20-diazadispiro [5.1.11.2] heneicosane-21-one, .beta.-alanine, N,-(2,2,6,6 -Tetramethyl-4 Piperidinyl) -dodecyl ester / tetradecyl ester, N-acetyl-3-dodecyl-1- (2,2,6,6-tetramethyl-4-piperidinyl) pyrrolidine-2,5-dione, 2,2,4, 4-Tetramethyl-7-oxa-3,20-diazadispiro [5.1.11.2] heneicosan-21-one, 2,2,4,4-tetramethyl-21-oxa-3,20-diazadicyclo- [5,1,11] -Heneicosan-20-propanoic acid dodecyl ester / tetradecyl ester, propanedioic acid, [(4-methoxyphenyl) -methylene] -bis (1,2,2,6,6) -Pentamethyl-4-piperidinyl) ester, higher fatty acid ester of 2,2,6,6-tetramethyl-4-piperidinol, 1,3-benzenedi Hinderamines such as ruboxyamide, N, N'-bis (2,2,6,6-tetramethyl-4-piperidinyl), benzophenones such as octabenzone, 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- [2-hydroxy-3- (3,4,5,6) -Tetrahydrophthalimido-methyl) -5-methylphenyl] benzotriazole, 2- (3-t-butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3,5) -Di-t-pentylphenyl) benzotriazole, methyl 3- (3- (2H-benzotriazol-2-yl) -5-t-butyl-4-hydride Reaction product of droxyphenyl) propionate with polyethylene glycol, benzotriazole-based compound such as 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol, 2,4-di-t- Benzoate systems such as butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) Although triazine type compounds, such as oxy] phenol, etc. are mentioned, Especially preferably, they are hindered amine type compounds.

When various additives are present in the composition, the weight ratio of various additives in the ultraviolet-curable adhesive composition is 0.01 to 3% by weight, preferably 0.01 to 1% by weight, more preferably It is 0.02 to 0.5% by weight.

The ultraviolet-curable adhesive composition of the present invention can be obtained by mixing and dissolving the above-described components at normal temperature to 80 ° C., and if necessary, impurities may be removed by an operation such as filtration. In the UV curable adhesive composition of the present invention, it is preferable to appropriately adjust the compounding ratio of the components so that the viscosity at 25 ° C. is in the range of 1 to 10000 mPa · s. The “25 ° C. viscosity” of the composition is measured at 25 ° C. using an E-type viscometer (TV-200: manufactured by Toki Sangyo Co., Ltd.). Furthermore, it is more preferable to appropriately adjust the compounding ratio of the components so that the viscosity at 25 ° C. is in the range of 1 to 6000 mPa · s, from the viewpoint of coatability to the substrate, the viscosity of 25 ° C. is 1 to 300 mPa · s. The range of s is more preferable, and the viscosity at 25 ° C. is more preferably in the range of 1 to 100 mPa · s. Furthermore, the viscosity at 25 ° C. is particularly preferably in the range of 1 to 80 mPa · s, very preferably in the range of 1 to 60 mPa · s, and the viscosity at 25 ° C. in the range of 1 to 30 mPa · s. Is most preferred. When the viscosity is higher than 10000 mPa · s, the coating property to the substrate is deteriorated, and the application of the ultraviolet curable adhesive composition is impossible, for example, the thin dispenser, the bar coater method, the ink jet method, etc. The method is limited.

In the ultraviolet curable adhesive composition of the present invention, the elongation at break of the cured product at 25 ° C. is preferably 200% or more, and more preferably 400% or more. Regarding “Elongation at break of cured product at 25 ° C.”, using a tensile tester (RTG-1210, manufactured by A & D Co., Ltd.), under the conditions of 25 ° C., the tensile speed is 100 mm / min, width 10 mm, length 30 mm It is measured by pulling the cured product of the UV curable adhesive composition of the present invention. Specifically, the elongation at break (%) is calculated by ([displacement length at break] / [length between chucks at start of measurement]) × 100. The cured product of the UV curable adhesive composition is prepared, for example, by the following method. First, two release films are prepared, the composition is dropped onto one of them, the release films are bonded together so that the thickness of the resin layer is 500 μm, and then a high pressure mercury lamp (80 W / cm, ozone-less) Then, the resin composition is cured by irradiating an ultraviolet ray with a cumulative light amount of 3000 mJ / cm ² . Subsequently, the cured resin is cut out into a width of 10 mm and a length of 30 mm, and the two release films are peeled to obtain a cured product. When the elongation at break is lower than 200%, it becomes difficult to follow the deformation of the substrate, and peeling is likely to occur when the substrate is curved or when a temperature environment such as low temperature or high temperature occurs. turn into.

Next, the preferable form of the manufacturing process of the optical member which uses the ultraviolet curable adhesive composition of this invention is demonstrated.

In the method for producing an optical member of the present invention, it is preferable that at least two optical substrates be bonded by the following (Step 1) to (Step 3). When it is judged that sufficient adhesive strength can be secured at the stage of (Step 2), it is possible to omit (Step 3).
(Step 1) The ultraviolet curable adhesive composition is applied to at least one optical substrate to form a coated layer, and the coated layer is irradiated with ultraviolet light to form an optical layer in the coated layer. The cured portion (hereinafter referred to as "cured portion of the cured product layer" or simply "cured portion") present on the substrate side (the lower side of the coated layer) and the opposite side to the optical substrate side (the upper portion of the coated layer) A step of obtaining an optical substrate having a cured product layer having an uncured portion (hereinafter referred to as "uncured portion of the cured product layer" or simply "uncured portion") present on the side, usually the atmospheric side) . In step 1, the curing rate of the coated layer after ultraviolet irradiation is not particularly limited, and an uncured portion exists on the surface opposite to the optical substrate (upper side of the coated layer, usually the air side). I wish I had it. After ultraviolet irradiation, when the side opposite to the optical substrate side (the upper side of the coating layer, usually the air side) is touched with a finger and the liquid component adheres to the finger, it can be judged as having an uncured portion.
(Step 2) Another optical substrate is bonded to the uncured portion of the cured product layer of the optical substrate obtained in Step 1, or the other optical substrate obtained in Step 1 is cured A process of bonding together the uncured portions of the product layer.
(Step 3) A step of irradiating the cured material layer having an uncured portion in the bonded optical substrate with ultraviolet light through the optical substrate having a light shielding portion to cure the cured material layer.
Hereinafter, a specific embodiment of the method for producing an optical member of the present invention through steps 1 to 3 will be described with reference to the drawings by taking a liquid crystal display unit and a transparent substrate having a light shielding portion as an example. Do.
Here, the UV curable adhesive composition of the present invention is applied in the state of liquid resin to at least one substrate when bonding two or more substrates together, and to the other substrate. It is applied in a liquid resin state or in a state having an uncured portion. In the case of curing with ultraviolet light after these are pasted together, a particularly excellent bonding effect can be obtained, and the presence of air can be prevented. Therefore, it is particularly preferable to use in such a case.

First Embodiment
FIG. 1 is a process chart showing a first embodiment of a manufacturing process of an optical member using the ultraviolet curable adhesive composition of the present invention.
This method is a method of obtaining an optical member by bonding the liquid crystal display unit 1 and the transparent substrate 2.
The liquid crystal display unit 1 refers to one in which a liquid crystal material is sealed between a pair of substrates on which electrodes are formed, and in which a polarizing plate, a drive circuit, a signal input cable, and a backlight unit are provided.
The transparent substrate 2 is a transparent substrate such as a glass plate, a polymethyl methacrylate (PMMA) plate, a polycarbonate (PC) plate, and an alicyclic polyolefin polymer (COP) plate.
Here, as the transparent substrate 2, one having a black frame-shaped light shielding portion 4 on the surface of the transparent substrate can be suitably used, and the light shielding portion 4 is formed by sticking of a tape, coating of paint, printing or the like. Although the present invention can be applied to those not having the light shielding portion 4, in the following description of the first to third embodiments, the case where the light shielding portion 4 is provided will be described as a specific example. In the case where the light shielding portion 4 is not provided, if “a transparent substrate having a light shielding portion” is read as a “transparent substrate”, it can be considered as an example where the light shielding portion is not provided.

(Step 1)
First, as shown in FIG. 1A, an ultraviolet-curable adhesive composition is applied to the display surface of the liquid crystal display unit 1 and the surface of the transparent substrate 2 having the light shielding portion on which the light shielding portion is formed. Do. The coating method may, for example, be a slit coater, a roll coater, a spin coater, a screen printing method, a bar coater, a doctor blade method or an inkjet method. Here, the UV curable adhesive composition applied to the surface of the liquid crystal display unit 1 and the transparent substrate 2 having the light shielding portion may be the same, or different UV curable adhesive compositions may be used. Absent. It is usually preferred that both be the same UV curable adhesive composition.
The film thickness of the cured product of each ultraviolet curable adhesive composition is adjusted so that the cured resin layer 7 after bonding is 10 to 500 μm, preferably 20 to 350 μm, and more preferably 30 to 150 μm. . Here, although the film thickness of the cured product layer of the ultraviolet curable adhesive composition present on the surface of the transparent substrate 2 having the light shielding part depends on the film thickness, it is usually present on the surface of the liquid crystal display unit 1 It is preferable that the thickness is as large as or thicker than the thickness of the cured layer of the UV curable adhesive composition. This is to minimize the portion remaining uncured even after irradiation with ultraviolet light in step 3 described later, thereby eliminating the possibility of curing failure.

The UV curable adhesive composition layer 5 after application is irradiated with UV light 8 to cure the lower portion of the coated layer (on the liquid crystal display unit side or the transparent substrate side as viewed from the UV curable adhesive composition) ( In the figure, the uncured part (not shown in the figure) present on the upper side of the coating layer (the side opposite to the liquid crystal display unit side or the side opposite to the transparent substrate side) (air side when performed in the atmosphere) A cured product layer 6 is obtained. The irradiation dose is preferably 5 to 2000 mJ / cm ² , particularly preferably 10 to 1000 mJ / cm ² . If the amount of irradiation is too small, the degree of curing of the ultraviolet curable adhesive composition of the finally bonded optical member may be insufficient. If the amount of irradiation is too large, the uncured component decreases and the liquid crystal display Bonding of the unit 1 and the transparent substrate 2 having the light shielding portion may be defective.
In the present invention, "uncured" refers to a fluidizable state at 25 ° C. environment. In addition, when the ultraviolet curable adhesive composition layer is touched with a finger after ultraviolet irradiation and the liquid component adheres to the finger, it is determined that the adhesive has an uncured portion.
For curing by ultraviolet to near-ultraviolet irradiation, any light source may be used as long as it is a lamp that emits ultraviolet to near-ultraviolet light. For example, low-pressure, high-pressure or ultra-high pressure mercury lamps, metal halide lamps, (pulsed) xenon lamps, LED lamps, electrodeless lamps and the like can be mentioned.
In Step 1 of the present invention, the wavelength of the ultraviolet light irradiated to the ultraviolet curable adhesive composition is not particularly limited, but when the maximum illuminance in the wavelength region of 320 nm to 450 nm is 100, the wavelength region of 200 to 320 nm 30 or less is preferable and, as for the ratio (illuminance ratio) of the largest illumination intensity in, it is especially preferable in it being 10 or less.
Assuming that the maximum illuminance in the wavelength region of 320 nm to 450 nm is 100, if the ratio of the maximum illuminance in the wavelength region of 200 to 320 nm (illuminance ratio) is higher than 30, the adhesive strength of the finally obtained optical member is inferior. There is a risk of This is because if the illuminance at a low wavelength is high, the curing of the ultraviolet curable adhesive composition proceeds excessively at the time of curing in Step 1, and the contribution to the adhesion at the time of curing in ultraviolet irradiation in Step 3 decreases. It is thought that it is because it does.

Here, as a method of irradiating the ultraviolet ray so as to obtain the above illumination ratio, for example, a method of applying a lamp satisfying the condition of the illumination ratio as a lamp for irradiating ultraviolet to near-ultraviolet light rays; Such illuminance by using a base material (for example, a short wave ultraviolet cut filter, a glass plate, a film, etc.) which cuts short wavelength ultraviolet rays at the time of irradiation in step 1 even if the conditions of the above are not satisfied. It becomes possible to irradiate with a ratio. Although it does not specifically limit as a base material which adjusts the illumination intensity ratio of an ultraviolet-ray, For example, the glass plate, the soda lime glass, PET film etc. to which the short wave ultraviolet-ray cutting process was performed are mentioned. In addition, the damping plate etc. which gave the unevenness | corrugation process to the surfaces, such as quartz glass, are not very effective. Since these scatter light and reduce the illuminance, they are not suitable for selectively reducing the illuminance of a short wavelength of 320 nm or less.
In step 1, irradiation with ultraviolet light is usually performed in the air at the upper surface on the coating side (the side opposite to the liquid crystal display unit side or the side opposite to the transparent substrate side from the ultraviolet curable adhesive composition) (normal air) It is preferable to irradiate from surface. In addition, it is also possible to perform irradiation of ultraviolet rays while spraying a curing inhibiting gas onto the upper surface of the coating layer after vacuuming. When the ultraviolet curable adhesive composition is cured in the air, the side opposite to the liquid crystal display unit side or the side opposite to the transparent substrate side is the air side. When it is desired to increase the tackiness of the surface of the coated layer formed in step 1, ultraviolet rays may be irradiated in a vacuum environment or environment of a gas such as nitrogen that does not cause curing inhibition.
On the other hand, in the case where the step 3 is omitted, curing can be suitably performed in vacuum or while spraying a gas (for example, nitrogen) that accelerates curing. As a result, even if step 3 is omitted, sufficient adhesion can be performed.

By blowing oxygen or ozone onto the surface of the ultraviolet curable adhesive composition layer (application layer) during ultraviolet irradiation, the state of the uncured portion and the film thickness of the uncured portion can be adjusted.
That is, by blowing oxygen or ozone to the surface of the coating layer, oxygen inhibition of the curing of the ultraviolet curable adhesive composition occurs on the surface, so that the uncured portion of the surface is ensured, or uncured. The film thickness of the portion can be increased.

(Step 2)
Next, as shown in FIG. 1B, the liquid crystal display unit 1 and the transparent substrate 2 having the light shielding portion are bonded to each other such that the uncured portions face each other. Bonding can be performed either in the air or in a vacuum.
Here, in order to prevent the formation of air bubbles during bonding, bonding in vacuum is preferable.
As described above, when the cured product of the ultraviolet curable adhesive composition having the cured portion and the uncured portion on each of the liquid crystal display unit and the transparent substrate is obtained and then bonded, improvement in adhesion can be expected.
Bonding can be performed by pressing, pressing or the like.

(Step 3)
Next, as shown in FIG. 1 (c), ultraviolet rays 8 are irradiated to the optical member obtained by bonding the transparent substrate 2 and the liquid crystal display unit 1 from the side of the transparent substrate 2 having the light shielding portion. The adhesive composition (coated layer) is cured.
The dose of ultraviolet rays is preferably about 100 ~ 4000mJ / cm ² in accumulated light quantity, particularly preferably 200 ~ 3000mJ / cm ² approximately. As a light source used for curing by irradiation of ultraviolet to near-ultraviolet light, any light source may be used as long as it is a lamp that irradiates ultraviolet to near-ultraviolet light. For example, low-pressure, high-pressure or ultra-high pressure mercury lamps, metal halide lamps, (pulsed) xenon lamps, LED lamps or electrodeless lamps etc. may be mentioned.
Thus, an optical member as shown in FIG. 4 can be obtained.

Second Embodiment
In addition to the first embodiment, the optical member of the present invention may be manufactured by the following modified second embodiment. The details of each step are the same as those in the first embodiment described above, and thus the description of the same parts will be omitted.

(Step 1)
First, as shown in FIG. 2 (a), an ultraviolet-curable adhesive composition is applied to the surface of the transparent substrate 2 having the light shielding portion on which the light shielding portion 4 is formed, and then the obtained applied layer (ultraviolet light The curable adhesive composition layer 5) is irradiated with ultraviolet light 8, and the cured portion present on the lower side of the coated layer (the transparent substrate side as viewed from the ultraviolet curable adhesive composition) and the upper side of the coated layer (transparent) A cured product layer 6 having an uncured portion present on the side opposite to the substrate side is obtained.
At this time, the wavelength of the ultraviolet light irradiated to the ultraviolet curable adhesive composition is not particularly limited, but when the maximum illuminance in the wavelength region of 320 nm to 450 nm is 100, the ratio of the maximum illuminance in the wavelength region of 200 to 320 nm Is preferably 30 or less, and more preferably 10 or less. Assuming that the maximum illuminance in the wavelength region of 320 nm to 450 nm is 100, if the ratio of the maximum illuminance in the wavelength region of 200 to 320 nm is higher than 30, the adhesive strength of the finally obtained optical member may be inferior. is there.

(Step 2)
Next, as shown in FIG. 2 (b), the transparent substrate 2 having the liquid crystal display unit 1 and the light shielding portion is formed in such a manner that the uncured portion of the obtained cured product layer 6 and the display surface of the liquid crystal display unit 1 face each other. to paste together. Bonding can be performed either in the air or in a vacuum.

(Step 3)
Next, as shown in FIG. 2 (c), ultraviolet rays 8 are irradiated to the optical member obtained by bonding the transparent substrate 2 and the liquid crystal display unit 1 from the side of the transparent substrate 2 having the light shielding portion. The cured product layer 6 having the uncured portion of the adhesive composition is cured.

Thus, the optical member shown in FIG. 4 can be obtained.

Third Embodiment
FIG. 3 is a process chart showing a third embodiment of a method for producing an optical member using the ultraviolet-curable adhesive composition of the present invention. The details of each step are the same as those in the first embodiment described above, and thus the description of the same parts will be omitted.
The same members as those in the first embodiment described above are designated by the same reference numerals in the drawings, and the description thereof will not be repeated here.

(Step 1)
First, as shown in FIG. 3A, an ultraviolet-curable adhesive composition was applied to the surface of the liquid crystal display unit 1. Thereafter, the ultraviolet curable adhesive composition layer 5 is irradiated with the ultraviolet light 8 so that the cured portion existing on the lower side of the coated layer (the transparent substrate side as viewed from the ultraviolet curable adhesive composition) and the upper portion of the coated layer A cured product layer 6 having uncured portions present on the side (opposite to the transparent substrate side) is obtained.
At this time, the wavelength of the ultraviolet light irradiated to the ultraviolet curable adhesive composition is not particularly limited, but when the maximum illuminance in the wavelength range of 320 nm to 450 nm is 100, the maximum illuminance in the wavelength range of 200 to 320 nm is 30. The following is preferable, and 10 or less is particularly preferable. Assuming that the maximum illuminance in the wavelength region of 320 nm to 450 nm is 100, if the maximum illuminance in the wavelength region of 200 to 320 nm is higher than 30, the adhesive strength of the finally obtained optical member is inferior.

(Step 2)
Next, as shown in FIG. 3 (b), the liquid crystal display unit 1 is formed such that the surface on which the light shielding portion is formed on the transparent substrate 2 having the light shielding portion and the uncured portion of the obtained cured product layer 6 is opposed. And the transparent substrate 2 having the light shielding portion are attached. Bonding can be performed either in the air or in a vacuum.

(Step 3)
Next, as shown in FIG. 3C, the ultraviolet curing is performed by irradiating the optical member obtained by bonding the transparent substrate 2 and the liquid crystal display unit 1 with ultraviolet light 8 from the transparent substrate 2 side having the light shielding portion. The cured product layer 6 having the uncured portion of the adhesive composition is cured.

Thus, the optical member shown in FIG. 4 can be obtained.

Each of the above-described embodiments describes some of the embodiments of the method for producing an optical member of the present invention with one specific optical substrate. Although each embodiment has been described using a transparent substrate having a liquid crystal display unit and a light shielding portion, in the manufacturing method of the present invention, various members described later can be used as an optical substrate instead of the liquid crystal display unit. Also for the transparent substrate, various members described later can be used as an optical substrate.
Furthermore, as optical substrates such as a liquid crystal display unit and a transparent substrate, a film bonded to these various members with another optical substrate layer (for example, a cured product layer of a UV curable adhesive composition) Or what laminated | stacked the other optical base material layer may be used.
Furthermore, the coating method of the ultraviolet curable adhesive composition, the film thickness of the resin cured product, the irradiation amount and the light source at the time of ultraviolet irradiation, and the ultraviolet curable adhesive composition described in the section of the first embodiment. The method of adjusting the film thickness of the uncured portion by blowing oxygen or nitrogen or ozone onto the layer surface is not limited to the above embodiment, but may be applied to any manufacturing method included in the present invention. it can.

Specific aspects of the optical member that can be manufactured in the first to third embodiments described above, including the liquid crystal display unit, are shown below.
(I) At least one optical substrate having a light shielding portion is selected from the group consisting of a transparent glass substrate having a light shielding portion, a transparent resin substrate having a light shielding portion, and a glass substrate on which a light shielding portion and a transparent electrode are formed. An optical substrate, and an optical substrate to be bonded to the optical substrate is at least one display unit selected from the group consisting of a liquid crystal display unit, a plasma display unit, and an organic EL unit, and an obtained optical member has the light shielding portion The aspect which is a display body unit which has an optical base material.
(Ii) One of the optical substrates is a protective substrate having a light shielding portion, and the other optical substrate to be bonded thereto is a touch panel or a display unit having a touch panel, and at least two optical substrates are bonded to each other The aspect whose optical member is a touch panel which has a protection base material which has a light-shielding part, or a display body unit which has it.
In this case, in the step 1, the ultraviolet curable adhesive composition as described above is applied to the surface provided with the light shielding portion of the protective substrate having the light shielding portion, or to one or both surfaces of the touch surface of the touch panel. Is preferably applied.
(Iii) One optical base is an optical base having a light shielding portion, another optical base to be bonded thereto is a display unit, and an optical member to which at least two optical bases are bonded is a light shielding portion The aspect which is a display body unit which has an optical base material which has these.

In this case, in the step 1, the above-mentioned UV-curable adhesive is applied to the optical substrate having the light shielding portion on the side provided with the light shielding portion, the display surface of the display unit, or both of them. It is preferred to apply the agent composition.
As a specific example of the optical substrate having a light shielding portion, for example, a protective plate for a display screen having a light shielding portion or a touch panel provided with a protective substrate having a light shielding portion can be mentioned.
For example, when the optical substrate having the light shielding portion is a protective plate for a display screen having the light shielding portion, the light shielding portion has a light shielding portion. It is the surface on the side where the part is provided. When the optical substrate having the light shielding portion is a touch panel having a protective substrate having the light shielding portion, the surface having the light shielding portion is bonded to the touch surface of the touch panel. From this, the surface on the side on which the light shielding portion of the optical base material having the light shielding portion is provided means the substrate surface of the touch panel opposite to the touch surface of the touch panel.
The light shielding portion of the optical substrate having the light shielding portion may be in any of the optical substrates, but is usually formed in a frame shape around the transparent plate-like or sheet-like optical substrate, and its width is 0. It is about 1 mm to 10 mm, preferably about 1 to 8 mm, and more preferably about 1.5 to 5 mm.

In the UV curable adhesive composition of the present invention, at least two optical substrates are bonded to each other by the above (Step 1) to (Step 2), and if necessary, (Step 3), the optical member is It can be used in the method of manufacturing.
The cure shrinkage of the cured product of the ultraviolet-curable adhesive composition of the present invention is preferably 10.0% or less, and particularly preferably 6.0% or less. Thereby, when the ultraviolet curable adhesive composition is cured, the internal stress accumulated in the resin cured product can be reduced, and the substrate and the layer made of the cured product of the ultraviolet curable adhesive composition It is possible to effectively prevent the interface from being distorted.
In addition, when the substrate such as glass is thin, if the curing shrinkage rate is large, the warpage at the time of curing becomes large, and the display performance is greatly adversely affected, so the curing shrinkage rate is also small from this viewpoint Is preferred.

The transmittance of the cured product of the ultraviolet curable adhesive composition of the present invention in the wavelength range of 450 nm to 800 nm is preferably 85% or more, and more preferably 90% or more. When the transmittance is less than 85%, it is difficult for light to be transmitted, and when used in a display device, the visibility is reduced.

The UV curable adhesive composition of the present invention can be suitably used as an adhesive for producing an optical member by laminating a plurality of optical substrates according to the above (Step 1) to (Step 3).
As an optical base material used in the manufacturing method of the optical member of this invention, a transparent plate, a sheet | seat, a touch panel, a display body unit etc. can be mentioned.
In the present invention, "optical substrate" means both an optical substrate having no light shielding portion on the surface and an optical substrate having a light shielding portion on the surface. In the method of manufacturing an optical member of the present invention, preferably, at least one of a plurality of optical substrates used is an optical substrate having a light shielding portion.

Various materials can be used as the material of the optical substrate used in the present invention. Specifically, resins such as PET, PC, PMMA, a composite of PC and PMMA, glass, COC, COP, polyimide, plastic (acrylic resin etc.) and the like can be mentioned. The optical substrate used in the present invention, for example, a transparent plate or sheet, is a sheet or transparent plate obtained by laminating a plurality of films or sheets such as polarizing plates, a sheet or transparent plate not laminated, and a transparent plate made of inorganic glass Plates (inorganic glass plates and their processed products such as lenses, prisms, ITO glass) and the like can be used. Moreover, the optical base material used in the present invention is a laminate comprising a plurality of functional plates or sheets such as a touch panel (touch panel input sensor) or a display unit described below in addition to the above-mentioned polarizing plate etc. Also referred to as "body".

As a sheet which can be used as an optical base material used for the present invention, an icon sheet, a makeup sheet, and a protection sheet are mentioned. As a board (transparent board) which can be used for the manufacturing method of the optical member of the present invention, a decorative board and a guard board are mentioned. As materials of these sheets or plates, those listed as materials of the transparent plate can be applied.
Examples of the material of the touch panel surface that can be used as an optical substrate used in the present invention include glass, PET, PC, PMMA, a composite of PC and PMMA, COC, and COP.
The thickness of the plate-like or sheet-like optical substrate such as a transparent plate or sheet is not particularly limited, and usually about 5 μm to about 5 cm, preferably about 10 μm to about 10 mm, more preferably about 50 μm to about 3 mm It is a thickness. Moreover, the optical base material that can be used as the optical base material used in the present invention can be any of a plate-like rigid base material and a thin and sheet-like base material that can be curved or rolled.

As a preferable optical member obtained by the manufacturing method of this invention, the plate-shaped or sheet-like transparent optical base material which has a light-shielding part, and the said functional laminated body harden | cure the ultraviolet curable adhesive composition of this invention The optical member bonded by the thing can be mentioned.
Further, in the manufacturing method of the present invention, a display unit with an optical functional material is used by using a display unit such as a liquid crystal display as one of the optical substrates and using an optical functional material as another optical substrate. Hereinafter, it can also be referred to as a display panel. As said display unit, display apparatuses, such as LCD which stuck the polarizing plate to glass, EL display, EL illumination, a quantum dot display, electronic paper, a plasma display, are mentioned, for example. Moreover, as an optical function material, transparent plastic boards, such as an acrylic board, PC board, a PET board, a PEN board, a cycloolefin board, a transparent polyimide resin, reinforced glass, a touch panel input sensor are mentioned.

When the optical substrate is used as an adhesive, the refractive index of the cured product is preferably 1.45 to 1.55 in order to improve the visibility. If it is in the range of the said refractive index, the difference of the refractive index with the base material used as an optical base material can be reduced, and it becomes possible to suppress irregular reflection of light and to reduce an optical loss.

The following (i) to (vii) can be mentioned as preferable embodiments of the optical member obtained by the production method of the present invention.
(I) An optical member in which an optical substrate having a light shielding portion and the functional laminate are bonded together using a cured product of the ultraviolet curable adhesive composition of the present invention.
(Ii) An optical substrate having a light shielding portion is a transparent glass substrate having a light shielding portion, a transparent resin substrate having a light shielding portion, a glass substrate on which a light shielding object and a transparent electrode are formed, a light shielding object and a transparent electrode The optical member according to the above (i), which is an optical substrate selected from the group consisting of transparent resin substrates, and the functional laminate is a display unit or a touch panel.
(Iii) The optical member according to (ii) above, wherein the display unit is any of a liquid crystal display unit, a plasma display unit and an organic EL display unit.
(Iv) The touch panel (or touch-panel input sensor) which bonded the plate-shaped or sheet-like optical base material which has a light-shielding part together using the hardened | cured material of the ultraviolet curable adhesive composition of this invention to a touch panel sensor.
(V) A display panel in which a plate-like or sheet-like optical substrate having a light shielding portion is pasted on a display screen of a display unit using a cured product of the ultraviolet curable adhesive composition of the present invention.
(Vi) The display panel according to (v), wherein the plate-like or sheet-like optical substrate having the light shielding portion is a protective substrate or a touch panel for protecting a display screen of the display unit.
(Vii) The ultraviolet ray curable adhesive composition according to any one of (i) to (vi) above, which is the ultraviolet ray curable adhesive composition according to any one of (1) to (9) above. Optical member, touch panel or display panel.

The optical member including the display body knit obtained by the manufacturing method of the present invention and the optical base having the light shielding portion may be incorporated into an electronic device such as a television, a small game machine, a mobile phone, a personal computer, or a wearable device. it can.

Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited by these examples.

Preparation of UV-Curable Adhesive Composition The mixture was heated and mixed at the compounding ratio shown in Table 1 to prepare resin compositions of compositions A to L.

A1: IRGACURE MBF (manufactured by BASF)
A2: IRGACURE 754 (manufactured by BASF)
A'1: IRGACURE 184 (manufactured by BASF)
A'2: Speed cure TPO (2,4,6-trimethyl benzoyl diphenyl phosphine oxide, manufactured by LAMBSON)
A'3: benzophenone (manufactured by Wako Pure Chemical Industries, Ltd.)
B1: Urethane acrylate (polypropylene glycol (weight average molecular weight 3000), isophorone diisocyanate, reaction product of three components of 2-hydroxyethyl acrylate in molar ratio 1: 1.3: 0.7, weight average molecular weight Mw 22000)
B2: Urethane acrylate (hydrogenated polybutadiene diol (weight average molecular weight 2000), isophorone diisocyanate, reaction product of three components of 2-hydroxyethyl acrylate in molar ratio 1: 1.2: 0.4, weight average molecular weight Mw 65000)
B3: Urethane acrylate (polypropylene glycol (weight average molecular weight 2000), isophorone diisocyanate, reactant of three components of 2-hydroxyethyl acrylate in molar ratio 1: 1.5: 1, weight average molecular weight Mw 11000)
B4: UC-203 (ester of maleic anhydride adduct of isoprene polymer and 2-hydroxyethyl methacrylate, manufactured by Kuraray Co., Ltd., weight average molecular weight Mw 35,000)
B'1: Urethane acrylate (polytetramethylene glycol (weight average molecular weight 650), isophorone diisocyanate, reactant of three components of 2-hydroxyethyl acrylate in molar ratio 1: 1.8: 1.7, weight average molecular weight Mw 2500)
C1: 4 HBA (4-hydroxybutyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
C2: MIRAMER M-1144 (o-phenylphenol (EO 2 mol) acrylate, manufactured by MIWON)
C-1-1: Brenmer LA (lauryl acrylate, manufactured by NOF Corporation)
C-1-2: NOAA (normal octyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
C-1-3: IDAA (isodecyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
C-1-4: NK ester S-1800A (isostearyl acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.)
C-2-1: Funcryl FA-513AS (dicyclopentanyl acrylate, manufactured by Hitachi Chemical Co., Ltd.)
C-2-2: IBXA (isobornyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
C-2-3: ACMO (Acryloyl morpholine, manufactured by KJ Chemicals Co., Ltd.)
X1: GI-2000 (both terminal hydroxyl group hydrogenated polybutadiene, manufactured by Nippon Soda Co., Ltd.)
X2: Pine Crystal KE311 (hydrogenated rosin ester resin, manufactured by Arakawa Chemical Co., Ltd.)

The following evaluations were performed using the obtained compositions A to L.

(viscosity)
The viscosity of the obtained composition was measured at 25 ° C. using an E-type viscometer (TV-200: manufactured by Toki Sangyo Co., Ltd.). The measurement results are shown in Table 2.

(Applicability)
The composition obtained using a bar coater was coated on a PET film of 100 μm thickness to a film thickness of 50 μm, and the state of the coated surface was visually confirmed.
:: application surface is uniform :: slight unevenness is observed on the application surface x: apparent unevenness is on the application surface

(Curable)
Two slide glasses having a thickness of 1 mm were prepared, and the obtained composition was dropped onto one of them, and two slide glasses were attached to each other so as to have a film thickness of 100 μm. The resin composition was cured by irradiating ultraviolet rays with a cumulative light quantity of 3000 mJ / cm ² with a high pressure mercury lamp (80 W / cm, ozone-free) through the glass. Thereafter, the two slide glasses were peeled off to confirm the cured state of the resin. The results are shown in Table 2.
:: The shape after curing is maintained and there is no flowability.
X: Liquid or liquid is drawn when peeling a slide glass, and has fluidity.

(Elongation at break)
Two release films are prepared, and the obtained composition is dropped onto one of them, and after bonding the release films so that the thickness of the resin layer is 500 μm, a high pressure mercury lamp (80 W / cm, ozone-free) The resin composition was cured by irradiation with ultraviolet light with an integrated light amount of 3000 mJ / cm ² . Thereafter, the cured resin is cut out to a width of 10 mm and a length of 30 mm, and the two release films are peeled off, and then the elongation at break of the cured resin is measured using a tensile tester (RTG-1210, manufactured by A & D Co., Ltd.) It was measured. The measurement conditions were 25 ° C. and a tensile speed of 100 mm / min, and the elongation at break (%) was calculated by ([displacement length at break] / [length between chucks at start of measurement]) × 100. The results are shown in Table 2.
:: Elongation at break 400% or more ○: Elongation at break 200% or more, less than 400% ×: Elongation at break less than 200%

(Base material deterioration)
The composition obtained is applied to a PET film of 100 μm thickness to a thickness of 100 μm, and bonded to a COP (cycloolefin polymer) film of 100 μm thickness, and then a high pressure mercury lamp (80 W / cm from the PET film side) ^The resin composition was cured by irradiating an ultraviolet ray with an integrated light amount of 3000 mJ / cm ^{2 with} no ozone. The obtained test piece was put into an 80 ° C. environment for 200 hours, and the presence or absence of cracks (breaks, cracks, etc.) of the COP film was confirmed using a microscope. The results are shown in Table 2.
○: There is no crack in the COP film.
X: The COP film is torn or cracked.

(Adhesiveness)
The composition obtained is applied to a 100 μm thick COP (cycloolefin polymer) film (4 sides 50 mm each) so as to be 100 μm thick, and the 100 μm thick PET film (width 60 mm, length 100 mm) Then, the resin composition was cured by irradiating an ultraviolet ray with a cumulative light quantity of 3000 mJ / cm ² from a PET film side with a high pressure mercury lamp (80 W / cm, ozone-less). The obtained test piece is set on a curved holding jig with a radius of curvature R = 50 mm so that the PET film is on the curved holding jig side (in the direction of contact with the curved surface of the holding jig). While being bent, it was put into a 60 ° C. environment for 250 hours. Then, the presence or absence of peeling of a test piece was confirmed visually. The results are shown in Table 2.
◎: no peeling.
Good: Peeling occurred at the end of the test piece (within 1 mm of the distance from the COP film end).
X: Peeling occurs in the plane of the test piece (the distance from the COP film end is more than 1 mm).

(transparency)
Prepare two slides of 1 mm thick slide glass coated with a fluorine-based mold release agent, and coat the obtained composition (compositions A to H, J to L) on one of the mold release agent coated surfaces of them. It applied so that thickness might be set to 200 micrometers. Then, two slide glasses were pasted together so that each release agent application side might face each other. The resin composition was cured by irradiating ultraviolet rays with a cumulative light quantity of 2000 mJ / cm ^{2 through} a glass with a high pressure mercury lamp (80 W / cm, ozone-free). Then, two slide glasses were exfoliated and the hardened material for transparency measurement was produced. For the transparency of the obtained cured product, the light transmittance in the wavelength region of 450 to 800 nm was measured using a spectrophotometer (U-3310, Hitachi High-Technologies Corporation). As a result, the light transmittance in the wavelength range of 450 to 800 nm was 85% or more.

Furthermore, the following evaluation was performed using the obtained composition A of the present invention.

(Heat resistant, moisture resistant adhesion)
A slide glass of 0.8 mm in thickness and an acrylic plate of 0.8 mm in thickness are prepared, and the composition A obtained on one side is coated to a film thickness of 200 μm, and then the other is attached to the coated surface The The resin composition was irradiated with ultraviolet light with an integrated light quantity of 3000 mJ / cm ^{2 through} a glass with a high pressure mercury lamp (80 W / cm, ozone-less) to cure the resin composition, and a sample for evaluating adhesion was prepared. This was left for 250 hours in an 85 ° C., 85% RH environment. In the evaluation sample, peeling of the slide glass or the acrylic plate from the cured resin was confirmed visually, but no peeling was observed.

(Curable of resin under light shielding part)
Composition A is formed on each of the substrates on the display surface of the liquid crystal display unit having an area of 3.5 inches and the surface on which the light shielding portion is formed on the transparent substrate having the light shielding portion (width 5 mm) in the outer peripheral portion. Was applied so as to be 50 μm. Then, using an electrodeless ultraviolet lamp (D bulb, manufactured by Heraeus Noble Light Fusion, Inc., D-bulb) on the coated layer obtained, the accumulated light amount from the atmosphere side through an ultraviolet cut filter that blocks light of wavelength 320 nm or less It was irradiated with ultraviolet light of 500 mJ / cm ² to form a cured product layer having a cured portion and an uncured portion present on the atmosphere side. The ratio of the maximum illuminance in the wavelength region of 200 to 320 nm was 3 when the maximum illuminance in the wavelength region of 320 nm to 450 nm was 100, and the ultraviolet light irradiated to the composition at this time was 100. Then, the transparent substrate which has a liquid crystal display unit and a light-shielding part was bonded together in the form which an unhardened part opposes. Finally, the resin cured product layer is cured by irradiating ultraviolet rays of an integrated light quantity of 3000 mJ / cm ² from a glass substrate side having a light shielding part with an ultra-high pressure mercury lamp (TOSCURE 752, manufactured by Harrison Toshiba Lighting Co., Ltd.), Made. The transparent substrate was removed from the obtained optical member, and the resin cured product layer in the light shielding portion was washed away with methylcyclohexane, and then the cured state was confirmed. There was no evidence that the uncured resin composition had been removed, and the resin of the light shielding portion was sufficiently cured.

(Flexibility)
Durability was evaluated by measuring durometer E hardness using a durometer hardness meter (type E) according to the method according to JIS K7215. More specifically, the obtained composition A was poured into a cylindrical mold so as to have a film thickness of 1 cm, and was irradiated with ultraviolet light to sufficiently cure the resin composition. The hardness of the obtained cured product was measured with a durometer hardness meter (type E). As a result, the measured value was less than 10 and the flexibility was excellent.

Although the present invention has been described in detail with reference to particular embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.
The present application is based on the Japanese patent application filed on October 4, 2017 (Japanese Patent Application No. 2017-193940) and the Japanese patent application filed on October 20, 2017 (Japanese Patent Application No. 2017-203051). Incorporated by reference in its entirety. Also, all references cited herein are taken as a whole.

DESCRIPTION OF SYMBOLS 1 liquid crystal display unit, 2 transparent substrate which has a light shielding part, 3 transparent substrate, 4 light shielding part, 5 ultraviolet curable resin composition (ultraviolet curable adhesive composition), 6 cured material layer which has 6 uncured parts, 7 resin Hardened layer, 8 UV rays

Claims (12)

A resin composition used to bond at least two optical substrates, including an intramolecular hydrogen abstraction type photopolymerization initiator (A), a photopolymerizable oligomer (B), and a (meth) acrylate monomer (C) The content of the solvent in the resin composition is 5% by weight or less, the weight average molecular weight of the photopolymerizable oligomer (B) is in the range of 7000 to 100000, and 450 to 800 nm of the cured product of the resin composition. The ultraviolet curable adhesive composition whose transmittance | permeability of the light in the wavelength range of is 85% or more. The photopolymerizable oligomer (B) is urethane (meth) acrylate, or (meth) acrylate having at least one skeleton selected from the group consisting of polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene and hydrogenated polyisoprene. The ultraviolet curable adhesive composition according to claim 1. The photopolymerizable oligomer (B) is a urethane (meth) acrylate having at least one or more skeleton selected from the group consisting of polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene and hydrogenated polyisoprene. 2. The ultraviolet curable adhesive composition as described in 2. The ultraviolet-curable adhesive composition according to any one of claims 1 to 3, which has a viscosity of 1 to 300 mPa · s at 25 ° C. The ultraviolet-curable adhesive composition according to any one of claims 1 to 3, which has a viscosity of 1 to 100 mPa · s at 25 ° C. The following formula (1) as a (meth) acrylate monomer (C)

(Wherein, X represents an acryloyl group or a methacryloyl group, and R ₁ represents an alkyl group having 8 to 18 carbon atoms)
The ultraviolet-curable adhesive composition according to any one of claims 1 to 5, which contains the monofunctional (meth) acrylate monomer (C-1) represented by The UV curable adhesive according to any one of claims 1 to 6, which contains a monofunctional (meth) acrylate monomer (C-2) having an alicyclic or heterocyclic ring as the (meth) acrylate monomer (C). Agent composition. The ultraviolet curable adhesive composition according to any one of claims 1 to 7, wherein the elongation at break at 25 ° C of the cured product is 200% or more. The optical substrate is a glass substrate, a transparent resin substrate, a glass substrate on which a transparent electrode is formed, a substrate in which a glass substrate or a film on which a transparent electrode is formed on a transparent substrate, a liquid crystal display unit, a plasma display unit The ultraviolet curable adhesive composition according to any one of claims 1 to 8, which is at least one optical base selected from the group consisting of and organic EL display units. The ultraviolet curable adhesive composition according to any one of claims 1 to 9, which is an ultraviolet curable adhesive composition for a touch panel. A cured product obtained by irradiating the ultraviolet ray curable adhesive composition according to any one of claims 1 to 10 with an active energy ray. A method of manufacturing an optical member having at least two optical substrates bonded to each other and having the following steps 1 to 2;
(Step 1) The ultraviolet-curable adhesive composition according to any one of claims 1 to 10 is applied to at least one optical substrate to form a coating layer, and ultraviolet light is applied to the coating layer. Step of obtaining an optical substrate having a cured product layer by irradiating (step 2) bonding the other optical substrate to the cured product layer of the optical substrate obtained in step 1 or A step of bonding the cured product layers of the other optical substrates obtained in 1.

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