TWI462982B - Binder for sticking optical functionality film, opitical functionality film with binder and manufacturing method thereof - Google Patents

Description

Optical functional film bonding adhesive, optical functional film with adhesive and preparation method thereof

The present invention relates to an adhesive for an optical functional film, an optical functional film with an adhesive, and a method for producing the same. More specifically, the present invention relates to an adhesive for an optical functional film, which is suitable for use in a polarizing plate, in particular, a polarizing plate integrated with a viewing angle expansion film or the like, or a phase difference plate laminated on a polarizing plate. In the case where the polarizing plate is adhered to the liquid crystal cell or the phase difference plate, good durability can be obtained, and the obtained liquid crystal display device does not have characteristics such as light leakage in a high temperature and high humidity environment; the optical with an adhesive Functional film and method of manufacturing the same.

In the past, when a sheet composed of an organic material such as glass, ceramics, or metal is adhered to an organic material through an adhesive, the sheet ends are often peeled off and floating is often caused.

In order to solve such a situation, it is common to increase the molecular weight of the components constituting the adhesive, to increase the crosslinking density, and the like, and to use a highly adhesive material having improved adhesion properties. However, in the case of using such a strong adhesive material, although the holding power is improved, under the condition of high temperature and high humidity, the sheet formed by the organic material shrinks and swells, and the adhesive cannot be changed, which is a cause of various problems. .

However, among the optical members, a polarizing plate is bonded to the surface thereof, and a liquid crystal cell of a liquid crystal display device (LCD) as a representative example thereof can be cited. Hereinafter, it will be explained using FIG.

The liquid crystal cell 13 generally has a configuration in which the inner side of the alignment layer of the two transparent electrode substrates on which the alignment layer has been formed is disposed in a predetermined interval between the spacers, and the periphery thereof is sealed to hold the liquid crystal material in the space while the liquid crystal material is held in the space. The polarizing plate 11 is placed on the two transparent electrode substrates via the adhesive 12, respectively. The polarizing plate is usually composed of a double-sided optically isotropic film of a polyvinyl alcohol-based polarizer, for example, a polarizing film having a three-layer structure such as a cellulose triacetate (TAC) film, and a single-sided sticker. An adhesive layer is provided for the purpose of attaching an optical member such as a liquid crystal cell.

Further, in the pattern diagram shown in FIG. 2, in order to improve the viewing angle characteristics, the phase difference plate 24 may be disposed between the polarizing plate 21 and the liquid crystal cell 23 via the adhesives 22 and 25.

When the polarizing plate having the above-described configuration is bonded to an optical member such as a liquid crystal cell, or when a polarizing plate and a phase difference plate are bonded together, it becomes a multilayer structure of a dissimilar material, and the dimensional stability of the material property is lacking, especially at a high temperature and high humidity. Under the environment, the dimensional changes caused by shrinkage and swelling are quite large. As the adhesive for the polarizing plate, since the above-mentioned strong adhesive property is usually used, it is possible to suppress floating and peeling as the size of the polarizing plate changes, but the size of the polarizing plate changes. The stress cannot be absorbed by the adhesive layer, and the residual stress in the polarizing plate becomes uneven. As a result, it has been found that the TN liquid crystal cell is likely to have a so-called "light leak", and the STN liquid crystal is likely to have a "spot" problem.

In order to solve such a problem, for example, a technique of imparting stress relaxation by appropriately softening a low molecular weight body such as a plasticizer to an adhesive (for example, refer to Patent Document 1). However, the addition of the low molecular weight body causes contamination of the adherend when the polarizing plate is peeled off, and the holding force is lowered, which tends to cause floating and peeling due to the passage of time.

Therefore, the object of coexistence of adhesion durability and light leakage prevention is a problem.

[Patent Document 1] Japanese Patent No. 3272921

In the present invention, the present invention provides an adhesive, which is suitable for the polarizing plate and the viewing angle expansion film integrated polarizing plate or the phase difference plate integrated polarizing plate and the liquid crystal cell glass, the polarizing plate and the phase difference plate. The phase difference plate and the phase difference plate, the luminance upward film and the phase difference plate, and the optical functional film are bonded to each other. That is, in order to provide an adhesive which is suitable for adhesion to the liquid crystal glass, it can have both durability and good adhesion in a high-temperature and high-humidity environment, and the obtained image display device has characteristics such as no light leakage. Further, when the optical functional films are bonded to each other, the disadvantages of the ends of the optical functional films can be suppressed in a high-temperature and high-humidity environment.

Further, the image display device mounted on a mobile phone or a car has a narrow outer frame portion around the screen, but the durability of the image display device and the light leakage resistance can be highly reliable. purpose.

The inventors of the present invention have repeatedly studied the development of an adhesive for an optical functional film having the above characteristics, and have found an adhesive which irradiates a specific acrylic copolymer with an active energy ray-curable compound-containing adhesive material with an active energy ray. The maximum shear load within 4000% of deformation is above a certain value and has a specific storage elastic modulus (G'), which is suitable for this purpose.

Further, it has been found that the optical functional film with an adhesive adheres to the optical functional film on the adhesive layer provided on the release layer of the release sheet, and the active energy ray is irradiated from the side of the release sheet, thereby achieving good efficiency. To manufacture.

The present invention has been accomplished in light of the above findings.

That is, the present invention provides: (1) an adhesive for optical functional film bonding characterized in that it is irradiated with an active energy ray (A) a monomer composition ratio of a carboxyl group-containing monomer of more than 0.5% by mass. An acrylic polymer and (B) an adhesive material including an active energy ray-curable compound, and bonded to an alkali-free glass at an adhesive area of 100 mm ² (10 mm × 10 mm) at a shear rate of 0.1 mm/min. When the shear load is measured, the maximum shear load within 4000% of deformation is 50 N or more, and the storage elastic modulus (G') at 23 ° C is 0.3 to 15 MPa; (2) The optical functional film as described in the above (1) The adhesive for bonding, which has a storage elastic modulus (G') of 80 to 10 MPa at 80 ° C, and (3) an optical functional film-bonding adhesive according to the above (1) or (2), wherein the optical agent The functional film is a polarizing plate, and the optical functional film bonding adhesive is used for bonding a polarizing plate to a liquid crystal cell; (4) The optical functional film as described in (1) or (2) above. The adhesive is used together, wherein the optical functional film is a polarizing plate and/or a phase difference plate, and the optical functional film bonding adhesive is used The bonding method of the polarizing plate and the phase difference plate or the bonding of the phase difference plate and the phase difference plate; (5) The optical functional film bonding adhesive according to the above (1) to (4), which contains (6) The optical functional film-bonding adhesive according to the above (1) to (5), wherein the active energy ray-curable compound of the component (B) has a molecular weight of less than (10) The optical functional film-bonding adhesive according to the above (6), wherein the polyfunctional (meth) acrylate system has a ring shape. (8) The optical functional film-bonding adhesive according to the above (7), wherein the polyfunctional (meth) acrylate system has a polyisocyanurate structure; (9) as described above (1) The adhesive for optical functional film bonding described in (8), wherein the ratio of the content of the component (A) to the component (B) is 100:1 to 100:100; (10) as described above (1) The adhesive for optical functional film bonding described in (9), wherein the adhesive material further has crosslinks containing (C) reactive groups with functional groups in the acrylic copolymer. And (D) an adhesive material of an organic decane coupling agent; (11) an optical functional film with an adhesive attached to at least one side of the optical functional film having the above (1) (10) The optical functional film with an adhesive as described in the above (11), wherein the optical functional film is a polarizing plate or a phase difference plate; (13) The optical functional film with an adhesive according to the above (11) or (12), which has an adhesion to an alkali-free glass: after bonding, it is 0.2 N/25 mm or more after 24 hours; and after lamination (4) A method for producing an optical functional film with an adhesive according to any one of the above (11) to (13), characterized in that it is an optical function After the adhesive film is bonded to the adhesive material layer provided on the release layer of the release sheet, the active energy ray is irradiated from the release sheet side.

According to the present invention, it is possible to provide an optical functional film adhesive which is suitable for use in a polarizing plate, in particular, a polarizing plate formed by integrating a viewing angle expansion film or the like, or in the case of a polarizing plate laminated phase difference plate. The polarizing plate is adhered to the liquid crystal cell or the phase difference plate to obtain good durability at the same time, and the obtained liquid crystal display device does not have light leakage characteristics in a high temperature and high humidity environment; and provides an optical function with the adhesive. film.

Further, according to the present invention, it is possible to provide a method for producing the optical functional film with an adhesive attached thereto with good efficiency.

The adhesive for an optical functional film of the present invention is bonded to an alkali-free glass with an adhesive area of 100 mm ² (10 mm × 10 mm), and the maximum shear of deformation within 4000% when the shear load is measured at a shear rate of 0.1 mm/min. The load is 50N or more. When the maximum shear load is 50 N or more, sufficient adhesion can be obtained at the same time, and durability in a high-temperature and high-humidity environment becomes good. The upper limit of the maximum shear load is about 200 N from the viewpoint of workability at the time of bonding. The maximum shear load is preferably from 50 to 150 N, more preferably from 75 to 130 N.

Further, the maximum shear load is a value measured by the following method.

<Method for Measuring Maximum Shear Load>

A 10 mm wide and 100 mm long sample was cut out from a polarizing plate with an adhesive, and the release sheet (adhesive layer thickness: 25 μm) was peeled off to be attached to the end of the alkali-free glass ("1737" manufactured by Corning). After the surface was placed in a manner of 10 mm × 10 mm, the pressure cooker manufactured by Kurihara Seisakusho Co., Ltd. was pressurized at 0.5 MPa, 50 ° C, and 20 minutes. Thereafter, after standing for 24 hours in an environment of 23° C. and a relative humidity of 50%, the end portion of the non-alkali glass on the unapplied side and the end portion of the unattached side of the sample were attached to the stretching in the same environment. A test machine (manufactured by Instron Co., Ltd.) was stretched in a shearing direction at a shear rate of 0.1 mm/min, and the load was measured. The measurement was carried out until the deformation amount was 4000% (the deformation amount in the shear direction was 1000 μm), and the maximum load up to 4000% deformation was taken as the maximum shear load. Further, the deformation is expressed by the ratio of the amount of deformation in the shear direction to the thickness of the adhesive layer.

Further, the adhesive modulus (G') of the adhesive of the present invention at 23 ° C must be 0.3 to 15 MPa. When the storage elastic modulus (G') is 0.3 MPa or more, sufficient light leakage prevention property can be obtained. Moreover, when it is 15 MPa or less, adhesive durability becomes favorable. From the above viewpoints, a storage elastic modulus (G') of particularly preferably 23 ° C is 0.35 to 12 MPa. Further, the storage elastic modulus (G') at 80 ° C is preferably from 0.1 to 10 MPa, more preferably from 0.3 to 3 MPa.

Further, the storage elastic modulus (G') is a value measured by the following method.

<Method for Measuring Storage Elastic Modulus (G')>

The storage elastic modulus (G') was an adhesive having a thickness of 30 μm to prepare a cylindrical test piece of 8 mm Φ × 3 mm thick, and the measurement was carried out by the torsional shear method under the following conditions.

Measuring device: Dynamic viscoelasticity measuring device manufactured by Flow Modification Co., Ltd. "DYNAMIC ANALYZER RDAII" Frequency: 1 Hz Temperature: 23 ° C, 80 ° C

The adhesive for an optical functional film of the present invention having the above-mentioned storage elastic modulus and adhesion is irradiated with an active energy ray (A) an acrylic polymer having a monomer composition ratio of a carboxyl group-containing monomer of more than 0.5% by mass, and B) An adhesive comprising an adhesive material of an active energy ray-curable compound.

The acrylic copolymer of the component (A) in the adhesive material may, for example, be a (meth)acrylate copolymer.

Further, in the present invention, the term "(meth)acrylate" means both an acrylate and a methacrylate. Other similar terms are the same.

In the above (meth) acrylate-based copolymer, a substance having a crosslinkable point is used in association with various crosslinking methods. The (meth) acrylate-based copolymer having such a cross-linking point is not particularly limited, and may be appropriately selected from conventional (meth) acrylate-based copolymers which are conventionally used as an adhesive resin component. .

Such a (meth) acrylate-based copolymer having a crosslinking point is preferably a (meth) acrylate having an alkyl group having an alkyl group number of 1 to 20 and a crosslinkable functional group in the molecule. a copolymer of a monomer and other monomers used as needed. Here, examples of the (meth) acrylate having an alkyl group having an alkyl group having 1 to 20 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. Butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylic acid Isooctyl ester, decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearic acid (meth) acrylate. These may be used alone or in combination of two or more.

On the other hand, the monomer having a crosslinkable functional group in the molecule preferably contains at least one of a hydroxyl group, a carboxyl group, an amine group and a guanamine group as a functional group, and specific examples thereof include (meth)acrylic acid 2- Hydroxyethyl ester, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, (A) (hydroxy) hydroxyalkyl (meth) acrylate such as 4-hydroxybutyl acrylate; acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-hydroxyl Acrylamide such as acrylamide or N-methylol methacrylamide; monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, (methyl) a monoalkylaminoalkyl (meth)acrylate such as monomethylaminopropyl acrylate or monoethylaminopropyl (meth)acrylate; acrylic acid, methacrylic acid, crotonic acid, maleic acid Ethylene saturated carboxylic acid such as itaconic acid or citraconic acid. These monomers may be used alone or in combination of two or more.

The acrylic polymer of the component (A) contains a monomer having a carboxyl group, and the monomer composition ratio is contained in an amount of more than 0.5% by mass. When the content of the monomer having a carboxyl group is more than 0.5% by mass, it can be sufficiently crosslinked by reaction with a crosslinking agent to be described later, and the durability is good. The content of the carboxyl group-containing monomer is preferably 0.55 to 15% by mass, particularly preferably 1 to 10% by mass. The monomer having a carboxyl group in the present invention is preferably (meth)acrylic acid.

The (meth) acrylate-based copolymer used as the component (A) in the adhesive material is not particularly limited in its copolymerization form, and any of random, block, and graft copolymers. Further, a material having a molecular weight of 500,000 or more by weight average molecular weight is used. When the weight average molecular weight is 500,000 or more, the adhesion to the adherend and the adhesion durability are sufficiently sufficient, and no floating or peeling occurs. When the adhesion and adhesion durability are considered, it is preferably a weight average molecular weight of 600,000 to 2.2 million, and particularly preferably 700,000 to 2,000,000.

Further, the weight average molecular weight is a value of converted polystyrene measured by a gel permeation chromatography (GPC) method.

The (meth) acrylate-based copolymer of the component (A) may be used singly or in combination of two or more.

The active energy ray-curable compound used as the component (B) in the adhesive material is preferably a polyfunctional (meth) acrylate monomer having a molecular weight of less than 1,000.

Examples of the polyfunctional (meth)acrylate monomer having a molecular weight of less than 1,000 include, for example, 1,4-butanediol (meth)acrylate, 1,6-hexanediol (meth)acrylate, and neopentane. Glycol (meth) acrylate, polyethylene glycol di(meth) acrylate, neopentyl glycol adipate di(meth) acrylate, hydroxy trimethyl acetic acid neopentyl glycol di(methyl) Acrylate, dicyclopentyl di(meth) acrylate, caprolactone modified dicyclopentenyl di(meth) acrylate, ethylene oxide modified di(meth) acrylate, di Propylene methoxyethyl) tripolyisocyanate, allylated cyclohexyl di(meth) acrylate, 9,9-bis[4-(2-propenyl methoxy ethoxy) phenyl] hydrazine, etc. Bifunctional; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, a trifunctional type such as propylene oxide modified trimethylolpropane tri(meth)acrylate or ginseng (propylene oxyethyl) tripolyisocyanate; dipropanetriol tetra(meth)acrylate, pentaerythritol a tetrafunctional type such as (meth) acrylate; a 5-functional type such as propionic acid-modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa(meth) acrylate; and caprolactone-modified dipentaerythritol hexa(methyl) a hexafunctional type such as an acrylate or the like.

In the present invention, the polyfunctional (meth)acrylate monomers may be used alone or in combination of two or more. Among them, those having a cyclic structure in the skeleton structure are preferred. The ring structure may be a carbon ring structure or a heterocyclic structure, or may be a single ring structure or a ring structure. Such a polyfunctional (meth) acrylate monomer, for example, a bis(propylene oxyethyl) tripolyisocyanate or a hexamethylene oxyethyl tripolyisocyanate having a triisocyanate structure; Hydroxymethyl dicyclopentane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecyl dimethanol acrylate, neopentyl glycol modified trimethylolpropane diacrylate Adamantane diacrylate, 9,9-bis[4-(2-propenyloxyethoxy)phenyl]anthracene or the like is suitable.

Further, an active energy ray-curable acrylate-based low polymer can be used as the component (B). The acrylate-based low polymer is preferably a weight average molecular weight of 50,000 or less. Examples of such an acrylate-based low polymer include polyester acrylate type, epoxy acrylate type, urethane acrylate type, polyether acrylate type, polybutadiene acrylate type, and poly Oxide acrylates and the like.

Here, the polyester acrylate-based oligomer can be esterified with (meth)acrylic acid by using a hydroxyl group of a polyester oligomer having a hydroxyl group at both ends thereof obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol. Alternatively, it can be obtained by esterifying a hydroxyl group at the terminal of the oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid using (meth)acrylic acid. The epoxy acrylate-based low polymer can be obtained, for example, by reacting a relatively low molecular weight bisphenol epoxy resin or a novolac epoxy resin of a novolak epoxy resin with (meth)acrylic acid to obtain an esterification product. . Further, a carboxyl group-modified epoxy acrylate oligomer having this epoxy acrylate-based low polymer modified with a partial dicarboxylic acid anhydride can also be used. An urethane acrylate oligomer, for example, a polyurethane oligomer which can be obtained by reacting a polyether polyol or a polyester polyol with a polyisocyanate, and esterifying with (meth)acrylic acid The polyol acrylate oligomer can be obtained by esterifying a hydroxyl group of a polyether polyol with (meth)acrylic acid.

The weight average molecular weight of the acrylate-based low polymer is a value converted by standard polymethyl methacrylate measured by a GPC method, preferably 50,000 or less, more preferably 500 to 50,000, and particularly preferably 3,000 to 40,000. Come choose.

These acrylate-based low polymers may be used alone or in combination of two or more.

In the present invention, an addition acrylate polymer having a group having a (meth)acryl fluorenyl group introduced into a side chain can be used as the component (B). The addition acrylate polymer is a (meth) acrylate described in the (meth) acrylate copolymer of the component (A), and a monomer having a crosslinkable functional group in the molecule. The copolymer is obtained by reacting a (meth) acrylonitrile group and a compound having a group reactive with a crosslinkable functional group among a crosslinkable functional group of the copolymer. The weight average molecular weight of the addition acrylate polymer is usually from 500,000 to 2,000,000 in terms of polystyrene.

In the present invention, one type of the polyfunctional acrylate monomer, the acrylate low polymer, and the addition acrylate polymer may be appropriately selected as the component (B), and two or more kinds may be used in combination.

In the present invention, the content ratio of the acrylic copolymer of the component (A) to the active energy ray-curable compound of the component (B) is preferably 100 in terms of the mass ratio of the obtained adhesive. : 1~100:100, more preferably 100:5~100:50, especially preferably 100:10~100:40.

Further, in the case where the adhesive of the present invention contains the components (A) and (B), the storage elastic modulus (G') after the irradiation of the active energy ray satisfies the above conditions. That is, the storage elastic modulus (G') at 23 ° C is 0.3 to 15 MPa, and more preferably, the storage elastic modulus (G') at 80 ° C is 0.3 to 10 MPa.

The adhesive material may optionally contain a photopolymerization initiator. Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, and benzoin isobutyl ether. , acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2- Hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2- Porphyrin-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2(hydroxy-2-propyl)one, diphenyl ketone, p-phenyldiphenyl ketone, 4,4'- Diethylaminodiphenyl ketone, dichlorodiphenyl ketone, 2-methyl hydrazine, 2-ethyl hydrazine, 2-tert-butyl fluorene, 2-amino hydrazine, 2-methyl Thiophenone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, Acetophenone dimethyl ketal, p-dimethylamino benzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2 , 4,6-trimethylbenzimidyl-diphenyl-phosphine oxide, and the like. These may be used singly or in combination of two or more kinds, and the blending amount thereof is usually in the range of 0.2 to 20 parts by mass based on 100 parts by mass of the above-mentioned (B) component.

The adhesive material may contain, as the component (C), a crosslinking agent reactive with a functional group in the acrylic copolymer, as needed. The crosslinking agent is not particularly limited, and can be appropriately selected from any of those conventionally used as a crosslinking agent in a conventional acrylic pressure-sensitive adhesive. Examples of such a crosslinking agent include a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, an anthracycline-based compound, a metal-clamping compound, and a metal alkoxide. A metal salt or the like, but a polyisocyanate compound is preferably used.

Here, examples of the polyisocyanate compound include an aromatic polyisocyanate such as toluene diisocyanate, diphenylmethane diisocyanate or xylylene diisocyanate, an aliphatic polyisocyanate such as hexamethylene diisocyanate, and isophorone diisocyanate. And an alicyclic polyisocyanate such as hydrogenated diphenylmethane diisocyanate, and the like, and the biuret or tripolyisocyanate, and ethylene glycol, propylene glycol, neopentyl glycol, and trishydroxyl An adduct of a reactant containing a low molecular weight active hydrogen compound such as propane or castor oil.

In the present invention, the crosslinking agent may be used singly or in combination of two or more. In addition, the amount of the crosslinking agent is usually from 0.01 to 20 parts by mass, preferably from 0.1 to 10 parts by mass, per 100 parts by mass of the (meth) acrylate-based copolymer.

The adhesive material may contain an organic decane coupling agent as the component (D) as needed. When the polarizing plate is bonded to, for example, a liquid crystal cell or the like by a mechanical decane coupling agent, the adhesion between the adhesive and the glass cell is further improved. The organic decane coupling agent is an organic ruthenium compound having at least one alkoxyalkylene group in the molecule, and is excellent in compatibility with an adhesive component and has light transparency. For example, it is preferably substantially transparent. The amount of the organic decane coupling agent to be added is preferably in the range of 0.001 to 10 parts by mass, particularly preferably in the range of 0.005 to 5 parts by mass, based on 100 parts by mass of the solid content of the adhesive material.

Specific examples of the organic decane coupling agent include a fluorene compound containing a polymerizable unsaturated group such as vinyl trimethoxy decane, vinyl triethoxy decane or 3-methyl propylene oxy propyl trimethoxy decane. An anthracene compound having an epoxy group structure such as 3-glycidoxypropyltrimethoxydecane or 2-(3,4-epoxycyclohexyl)ethyltrimethoxydecane, 3-aminopropyl Trimethoxydecane, N-(2-aminoethyl)-3-aminopropyltrimethoxydecane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxy An amine group-containing hydrazine compound such as decane or 3-chloropropyltrimethoxydecane. These may be used alone or in combination of two or more.

The adhesive material may be added to the acrylic adhesive as necessary to impart various additives generally used, such as an adhesive, an antioxidant, an ultraviolet absorber, a light stabilizer, a softener, a filler, and the like, as long as the object of the present invention is not impaired.

The adhesive for an optical functional film of the present invention is obtained by irradiating the above-obtained adhesive material with an active energy ray.

Examples of the active energy ray include ultraviolet rays, electron beams, and the like. The ultraviolet rays may be a high pressure mercury lamp, an electrodeless lamp, a xenon lamp or the like. On the other hand, the electron beam is obtained by an electron beam accelerator or the like. Among the active energy rays, ultraviolet rays are particularly preferred. Further, when an electron beam is used, an adhesive can be formed without adding a photopolymerization initiator.

The active energy ray irradiation amount of the adhesive material can be appropriately selected from the adhesive having the storage elastic modulus and the adhesion to the alkali-free glass and the polycarbonate. However, in the case of ultraviolet light, the illuminance is preferably 50. ~1000 mW/cm ² and a light amount of 50 to 1000 mJ/cm ² , in the case of an electron beam, preferably in the range of 10 to 1000 krad.

The adhesive for optical functional film of the present invention is suitable for a polarizing plate composed of a polarizing film alone, and the polarizing plate can be used, for example, to adhere to a liquid crystal cell, but is particularly suitable for integrating a polarizing film and a viewing angle. The polarizing plate is preferably formed by adhering the polarizing plate to, for example, a liquid crystal glass cell.

The polarizing plate in which the polarizing film and the viewing angle expansion film are integrated, for example, a single-sided film of a polarizing film formed by laminating a cellulose triacetate (TAC) film on both sides of a polyvinyl alcohol-based polarizer is used. For example, the functional layer is formed by applying a viewing angle to form a disk-shaped liquid crystal, or the film is expanded by attaching a viewing angle with an adhesive. In this case, the adhesive is provided on the viewing angle expansion function layer or the viewing angle expansion film side.

Further, as shown in Fig. 2, when a phase difference plate is provided between the polarizing plate and the liquid crystal glass cell, the optical functional film adhesive of the present invention can be suitably used. In other words, an optical film in which a polarizing plate and a phase difference plate which are separately formed of a polarizing film of the present invention are bonded to each other, and a phase difference plate and a liquid crystal glass cell of the optical film are bonded together with an adhesive. Here, the adhesive for bonding the phase difference plate and the liquid crystal glass cell is not particularly limited, and an adhesive generally used for bonding the polarizing plate and the liquid crystal glass cell can be used. Specifically, an adhesive composition composed of an acrylic copolymer, a crosslinking agent, and a decane compound disclosed in JP-A-H11-131033, and the like can be mentioned. Further, the adhesive of the present invention can also be used for bonding the polarizing plate to the liquid crystal glass cell.

The adhesive of the present invention preferably has a gel fraction of 85% or more. In other words, when the amount of low-molecular-weight components extracted in an organic solvent is small, it is less likely to be floated, peeled off, and contaminated with adherends under heating and under warm conditions, and the gel fraction is 85% or more. The durability and stability of the agent are high. The gel fraction is preferably from 90 to 99.9%.

By using the adhesive for an optical functional film of the present invention, a liquid crystal display device produced by adhering a polarizing plate to a liquid crystal glass cell or a phase difference plate as described above does not cause light leakage in a high-temperature and high-humidity environment, and the polarizing plate Excellent adhesion to liquid crystal glass cells.

Further, the present invention provides an optical functional film with an adhesive attached to a polarizing plate with a layer comprising the above-mentioned optical functional film adhesive of the present invention. The polarizing plate in the optical functional film may be a separate material of the polarizing film as described above. However, in the case of the configuration shown in Fig. 1, it is preferable that the polarizing film and the viewing angle expansion film are integrated. Things.

Further, the thickness of the layer made of the optical functional film adhesive is generally from about 1 to 100 μm, preferably from 1 to 50 μm, more preferably from 2 to 30 μm.

The method for producing an optical functional film with an adhesive may be a method in which a layer composed of the adhesive of the present invention is provided on an optical functional film such as a polarizing plate, and is not particularly limited, but The method of the present invention is shown to produce the desired optically functional film with an adhesive with good efficiency.

In the method of the present invention, an optical functional film such as a polarizing plate is bonded to the adhesive material layer provided on the release layer of the release sheet, and the active energy ray is irradiated onto the adhesive material layer from the release sheet side. The optical functional film with an adhesive of the present invention can be obtained in such a manner that it is a layer composed of the adhesive of the present invention having the specific characteristics described above.

The release sheet may be a polyester film such as polyethylene terephthalate, polybutylene terephthalate or polyethylene naphthalate; or a plastic film such as a polyolefin film such as polypropylene or polyethylene. A release agent such as a polyoxymethylene resin is applied to provide a release layer. The thickness of the release sheet is not particularly limited, but is generally about 20 to 150 μm.

Further, the irradiation conditions of the adhesive material and the active energy ray are similar to those described in the above-mentioned adhesive for optical functional film of the present invention.

The method of providing an adhesive material layer on the release sheet can be carried out by applying an adhesive material to the coating film by, for example, a bar coating method, a knife coating method, a roll coating method, a flat coating method, a die coating method, a gravure coating method, or the like. , the method of drying. The drying conditions are not particularly limited, but are generally from 10 to 10 minutes at 50 to 150 °C.

Further, in the case of the configuration shown in Fig. 2, the polarizing plate is formed of a single film alone, and the thickness of the layer made of the optical functional film adhesive is the same as described above. The method for producing a polarizing plate with an adhesive attached to the configuration shown in Fig. 2 may be a member provided with a layer composed of the adhesive of the present invention on the same polarizing plate as described above, but is not particularly limited. The above-described manufacturing method of the present invention can be efficiently produced.

Further, in the case of the configuration shown in Fig. 2, an adhesive sheet composed of the above-mentioned adhesive for polarizing plates may be held adjacent to the peeling layer side of the two release sheets, and the polarizing plate may be attached by the adhesive sheet. And the phase difference plate. When the component (B) is used as the adhesive here, the active energy ray may be irradiated after the adhesive is applied to the two release sheets, or the adhesive may be provided on one of the release sheets, and the other energy may be applied after irradiation with the active energy ray. sheet. Further, the irradiation conditions of the active energy ray are selected in accordance with the layer composed of the adhesive of the present invention having the specific characteristics described above.

The optical functional film with an adhesive attached to the present invention has an adhesion to an alkali-free glass, and is 0.2N/25 mm or more after 24 hours after bonding; and preferably after bonding, after 40 days, it is 40N. /25mm or more. When the adhesive force after the lapse of 24 hours is 0.2 N/25 mm or more, an optical functional film such as a polarizing plate can be bonded to, for example, a liquid crystal glass cell with sufficient adhesion. More preferably, the adhesion is 1.0 to 35 N/25 mm. Further, when the adhesive force after the lapse of 7 days is 40 N/25 mm or more, the above-mentioned bonding becomes stronger. Better Adhesive force is 45N/25mm or more. The upper limit of the adhesive force is not particularly limited, but is generally about 50 N/25 mm because of the strength relationship of the optical functional film.

Further, the method for measuring the above adhesive force is described in detail later.

[Examples]

The invention is described in more detail by way of examples, but the invention is not limited thereto.

Further, the properties of the adhesives obtained in Examples 1 to 6 and Comparative Example 1 and the properties of the polarizing plate with an adhesive were obtained by the following description.

(1) Storage elastic modulus of adhesive

The storage elastic modulus at 23 ° C and 80 ° C was measured according to the method described herein.

(2) Adhesion (adhesion to alkali-free glass)

A sample of 25 mm width and 100 mm length was cut out from a polarizing plate with an adhesive, and the release sheet was peeled off (the thickness of the adhesive layer was 25 μm) and attached to an alkali-free glass ("1737" manufactured by Corning Co., Ltd.). The pressure cooker manufactured by the company was pressurized at 0.5 MPa, 50 ° C, and 20 minutes. Thereafter, after standing for 24 hours or 168 hours in an environment of 23° C. and a relative humidity of 50%, adhesion was measured under the same conditions using a tensile tester (tensilon manufactured by Orieteck Co., Ltd.) at a peeling speed of 300 mm/min and a peeling angle of 180°. force.

(3) Maximum shear load

According to the method described in the specification, the maximum shear load up to 4000% deformation was obtained.

(4) Gel fraction

The adhesive was sampled to a size of 80 mm x 80 mm with a thickness of 25 μm, and the weight of the adhesive which was only wrapped in a polyester mesh (screen size 200) was weighed with a precision balance. The weight at this time is taken as M1. The adhesive was immersed in a solvent of ethyl acetate with a Soxhlet (extractor) and refluxed for 16 hours. Thereafter, the adhesive was taken out, air-dried for 24 hours in an environment of a temperature of 23 ° C and a relative humidity of 50%, and further dried in an oven at 80 ° C for 12 hours. After drying, use a precision balance to weigh only the weight of the adhesive. The weight at this time is taken as M2. The gel fraction is expressed by (M2/M1) × 100 (%).

(5) Durability of the polarizing plate with the adhesive The polarizing plate with the adhesive is adjusted to a size of 233 mm × 309 mm by a cutting device ("Super Pinch Machine" "PN1-600" manufactured by Takino Seiki Co., Ltd.) After the alkali-free glass ("1737" manufactured by Corning Co., Ltd.), the pressure cooker manufactured by Kurihara Co., Ltd. was pressurized at 0.5 MPa, 50 ° C, and 20 minutes. After that, it was taken out after 200 hours in an environment of the following durability conditions, and the lens was observed with a 10× magnification lens in an environment of 23° C. and a relative humidity of 50%, and the durability was evaluated by the following criteria.

○: Among the four sides, there is no defect in the outer peripheral end portion of 0.6 mm or more.

△: On one of the four sides, there is an abnormality in the appearance of the adhesive which is less than 0.1 mm from the outer peripheral end portion of 0.6 mm or more, such as floating, peeling, foaming, and line.

×: On one of the four sides, there is an abnormality in the appearance of an adhesive having a thickness of 0.1 mm or more, such as floating, peeling, foaming, or line, from the outer peripheral end portion of 0.6 mm or more.

<Endurance condition> 60 ° C. Relative humidity 90% environment, 80 ° C, 90 ° C -20 ° C 30-minute thermal shock test at 60 ° C, 200 cycles

(6) Light leakage performance The polarized light with an adhesive is adjusted to a size of 233 mm × 309 mm by a cutting device ("Super Pinch Machine "PN1-600" manufactured by Takino Seiki Co., Ltd.), and bonded to an alkali-free glass [Korning Co., Ltd. After the "1737" was produced, the pressure cooker manufactured by Kurihara Co., Ltd. was pressurized at 0.5 MPa, 50 ° C, and 20 minutes. Further, the polarizing plate with the adhesive attached to the surface of the non-alkali glass is bonded to the Nikon orthogonal state. This state was allowed to stand at 80 ° C for 200 hours. Thereafter, the mixture was allowed to stand in an environment of 23 ° C and a relative humidity of 50% for 2 hours, and the light leakage property was evaluated by the following method under the same environment.

Using the MCPD-2000 manufactured by Otsuka Electronics Co., Ltd., the brightness of each field shown in Fig. 3 was measured, and the lightness difference ⊿L ^{* was} obtained by the following equation as the light leakage property: ⊿L ^* = [(b + c + d + e) / 4] - a

(However, a, b, c, d, and e are the brightness of predetermined measurement points (one position in the central part of each field) in the A field, the B field, the C field, the D field, and the E field, respectively.). The smaller the value of ⊿L ^* , the less the light leakage.

(7) Durability of the optical film The optical film was adjusted to a size of 100 mm × 174 mm by a cutting device (Super Pinch Machine "PN1-600" manufactured by Takino Seiki Co., Ltd.), and the adhesive side of the phase difference plate was attached to the thickness. After a 700 μm alkali glass ("1737" manufactured by Corning Co., Ltd.), the pressure cooker manufactured by Kurihara Co., Ltd. was pressurized at 0.5 MPa, 50 ° C, and 20 minutes. After that, the mixture was taken out in an environment of the following durability conditions for 200 hours, and the interface between the polarizing plate and the phase difference plate was observed with a 10× magnification lens in an environment of 23° C. and a relative humidity of 50%, and the durability was evaluated by the following criteria. Sex.

○: Among the four sides, the interface between the polarizing plate and the phase difference plate did not float or peel off.

×: One of the four sides, the interface between the polarizing plate and the phase difference plate floats and peels off.

<Endurance condition> 60 ° C. Relative humidity 90% environment, 80 ° C, 90 ° C -20 ° C Thermal shock test at 60 ° C for 30 minutes, 200 cycles

Examples 1 to 9 and Comparative Examples 1, 2

(1) Preparation of a polarizing plate with an adhesive The adhesive material (a) having the composition shown in Table 1 was prepared, and a polyethylene terephthalate peeling film having a thickness of 38 μm as a release sheet was used. The peeling layer of "SP-PET3811" manufactured by the company was applied by a knife coater so as to have a thickness of 25 μm after drying, and then dried at 90 ° C for 1 minute to form an adhesive material layer.

Adhesively, a polarizing film comprising a polarizing film having a disk-shaped liquid crystal layer and a polarizing plate integrated with a viewing angle expansion film are bonded to each other such that the adhesive material layer and the disk-shaped liquid crystal layer are joined to each other. After bonding for 30 minutes, ultraviolet rays (UV) were irradiated from the peeling film side under the following conditions, and then conditioned for 10 days in an environment of 23 ° C and a relative humidity of 50% to prepare a polarizing plate with an adhesive. The thickness of the adhesive layer is 25 μm.

<UV irradiation conditions>. Use the electrodeless lamp H bulb made by Fusion. Illuminance 600mW/cm ² , light quantity 150mJ/cm ² UV illuminance. For the light meter, "UVPF-36" manufactured by Eye Graphics Co., Ltd. was used.

The results of the evaluation of the properties of the adhesive and the performance of the polarizing plate with the adhesive are shown in Table 2.

(2) Production of optical film (manufacture of polarizing plate with adhesive) The adhesive material of the composition shown in Table 1 was used as a peeling film of polyethylene terephthalate having a thickness of 38 μm as a release sheet [ The peeling layer of "SP-PET3811" manufactured by Linde Co., Ltd. was coated with a knife coater so as to have a thickness of 15 μm after drying, and then dried at 90 ° C for 1 minute to form an adhesive layer. .

Adhesively, a polarizing plate (thickness: 180 μm) composed of a polarizing film was bonded to the adhesive material layer, and after bonding for 30 minutes, the film was irradiated with ultraviolet rays having the same conditions as above from the peeling film side, and then at 23 ° C and a relative humidity of 50. The condition of % was adjusted for 10 days, and a polarizing plate with an adhesive was produced.

(Adhesive processing of a phase difference plate) on a release layer of a polyethylene terephthalate release film ("SP-PET3811" manufactured by Linde Co., Ltd.) having a thickness of 38 μm as a release sheet, and a thickness after drying The adhesive (b) was applied to a 25 μm method by a knife coater, and then dried at 90 ° C for 1 minute to form an adhesive material layer.

The adhesive (b) is a trimethylolpropane-modified toluene diisocyanate blended with 0.3 parts by mass of an isocyanate crosslinking agent in 100 parts by mass of a base material having a ratio of butyl acrylate to acrylic acid of 95/5. (Kronate L, manufactured by Japan Polyurethane Co., Ltd.), and 3-glycidoxypropyltrimethoxydecane (0.3M MK-403, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.3 parts by mass of an organic decane coupling agent ) Adhesive.

A cyclic hydrocarbon film ("zeonoa ZF116" manufactured by Optus Co., Ltd., thickness: 100 μm) was used as a phase difference film, and the above-mentioned adhesive material layer was bonded to the upper layer, and then conditioned at 23 ° C and a relative humidity of 50% for 10 days. .

(Production of Optical Film) The release film of the polarizing plate with the adhesive was peeled off, and the film was bonded to the non-adhesive side of the phase difference plate on which the adhesion treatment was applied to obtain an optical film.

The evaluation results of the properties of the optical film are shown in Table 3.

<acrylic polymer>1

A1: a copolymer of butyl acrylate and acrylic acid in a mass ratio of 95:5, polymerized according to a conventional method, and having a weight average molecular weight of 1.8 million.

A2: a copolymer of butyl acrylate and acrylic acid in a mass ratio of 96:4, polymerized according to a conventional method, and having a weight average molecular weight of 1.8 million.

A3: a copolymer of butyl acrylate and acrylic acid in a mass ratio of 98:2, polymerized according to a conventional method, and having a weight average molecular weight of 1.8 million

A4: a copolymer of butyl acrylate and acrylic acid in a mass ratio of 99:1, polymerized according to a conventional method, and having a weight average molecular weight of 1.5 million.

<Active energy ray-hardening compound>

M-315: propylene (propylene oxyethyl) tripolyisocyanate, molecular weight = 423, trifunctional (manufactured by Toagosei Co., Ltd., trade name "Aronix M-315")

R-684: Tricyclodecyl dimethanol acrylate (KAYARAD R-684, manufactured by Nippon Kayaku Co., Ltd., molecular weight = 336)

A-BREF: 9,9-bis[4-(2-propenyloxyethoxy)phenyl]anthracene (manufactured by Shin-Nakamura Chemical Co., Ltd., molecular weight = 546, 2-functional)

<crosslinker>

C1: Isocyanate crosslinking agent [trimethylolpropane modified toluene diisocyanate (Kronate L manufactured by Nippon Polyurethane Co., Ltd.)]

C2: epoxy group-based crosslinking agent ("TETRAD-C" manufactured by Mitsubishi Gas Chemical Co., Ltd.)]

<Organic decane coupling agent> 3-glycidoxypropyltrimethoxydecane ("KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.)

<Photopolymerization Initiator> A mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1:1, "Irgacure 500" manufactured by Diebat Chemical Co., Ltd.

*: The adhesion is too large and the adhesive polarizer is broken. The adhesion force at break is 50N/25mm, so the actual adhesion is more than 50N/25mm.

[Industrial Availability]

An adhesive for an optical functional film of the present invention, which is suitable for use in a polarizing plate, in particular, a polarizing plate formed by integration with a viewing angle expansion film, or in the case where a polarizing plate is laminated with a phase difference plate, the polarizing plate is adhered thereto. The liquid crystal cell or the phase difference plate can have good durability at the same time, and the obtained liquid crystal display device does not exhibit light leakage or the like in a high temperature and high humidity environment.

1, 2. . . Liquid crystal display device

11, 21. . . Polarizer

12, 22, 25. . . Adhesive

13,23. . . Glass (liquid crystal cell)

twenty four. . . Phase difference plate

Fig. 1 is a schematic view showing the structure of an LCD.

Fig. 2 is a schematic view showing the structure of the LCD.

Fig. 3 is an explanatory view showing a method of evaluating the light leakage property of the polarizing plate with an adhesive obtained in the examples and the comparative examples.

Claims (16)

An adhesive for optical functional film bonding, characterized in that the monomer composition ratio of (A) a carboxyl group-containing monomer is more than 0.5% by mass and the weight average molecular weight is 500,000 or more by an active energy ray. An acrylic polymer, (B) an active energy ray-curable compound of a polyfunctional (meth) acrylate monomer having a molecular weight of less than 1,000, and a photopolymerization initiator, and the components (A) and (B) The ratio is made of an adhesive material with a mass ratio of 100:5 to 100:50. For an alkali-free glass, the bonding area is 100 mm ² (10 mm × 10 mm), and the shearing speed is 0.1 mm/min. When the load is cut, the maximum shear load within 4000% of deformation is 50 N or more, and the storage elastic modulus (G') at 23 ° C is 0.3 to 15 MPa. The optical functional film-bonding adhesive according to the first aspect of the invention is characterized in that the storage elastic modulus (G') at 80 ° C is 0.3 to 10 MPa. The optical functional film-adhesive adhesive according to claim 1, wherein the optical functional film is a polarizing plate, and the optical functional film-adhesive adhesive is used for bonding the polarizing plate to the liquid crystal glass cell. . The optical functional film-adhesive adhesive according to claim 1, wherein the optical functional film is a polarizing plate and/or a phase difference plate, and the optical functional film-adhesive adhesive is used for a polarizing plate and The phase difference plate is bonded or the phase difference plate is combined with the phase difference plate. An adhesive for optical functional film bonding according to claim 1, wherein the monomer having a carboxyl group is (meth)acrylic acid. The adhesive for optical functional film bonding according to the first aspect of the invention, wherein the content of the monomer having a carboxyl group in the component (A) is from 0.55 to 15% by mass based on the monomer composition ratio. The adhesive for optical functional film bonding according to the first aspect of the invention, wherein the content of the monomer having a carboxyl group in the component (A) is 4 to 15% by mass based on the monomer composition ratio. The adhesive for optical functional film bonding according to claim 1, wherein the weight average molecular weight of the component (A) is from 600,000 to 2,200,000. The adhesive for optical functional film bonding according to the first aspect of the patent application has a gel fraction of 85% or more. The adhesive for optical functional film bonding according to claim 1, wherein the polyfunctional (meth) acrylate system has a ring structure. The optical functional film-fitting adhesive according to claim 10, wherein the polyfunctional (meth) acrylate system has a three-polyisocyanurate structure. The adhesive for optical functional film-adhesive according to claim 1, wherein the adhesive material further contains (C) a crosslinking agent reactive with a functional group in the acrylic copolymer, and (D) Adhesive material for organic decane coupling agents. An optical functional film with an adhesive, characterized in that it is attached to at least one side of an optical functional film and has a scope as claimed in the patent application. The layer formed by the adhesive of item 1. An optical functional film with an adhesive as disclosed in claim 13 wherein the optical functional film is a polarizing plate or a phase difference plate. An optical functional film with an adhesive attached to the thirteenth article of the patent application, the adhesion to the alkali-free glass is: after bonding, it is 0.2 N/25 mm or more after 24 hours; and after bonding, after the bonding After 7 days, it is 40N/25mm or more. An optical functional film with an adhesive, which is used for manufacturing an optical functional film with an adhesive as disclosed in any one of claims 13 to 15, which is characterized in that it is optical After the functional film is bonded to the adhesive material layer provided on the release layer of the release sheet, the active energy ray is irradiated from the release sheet side.