WO2020111235A1

WO2020111235A1 - Polarizing film with adhesive layer, and image display device

Info

Publication number: WO2020111235A1
Application number: PCT/JP2019/046795
Authority: WO
Inventors: 智之木村; 康隆石原; 雄祐外山; 聡司三田
Original assignee: 日東電工株式会社
Priority date: 2018-11-29
Filing date: 2019-11-29
Publication date: 2020-06-04

Abstract

This polarizing film with an adhesive layer comprises a polarizing film and an adhesive layer. The polarizing film comprises a polarizing element, a transparent protective film on only one surface of the polarizing element, and a conductive layer on the other one surface of the polarizing element with a transparent layer therebetween that is no more than 10 μm thick and that is formed directly on the polarizing element. The adhesive layer is provided on the polarizing film with the aforementioned conductive layer interposed therebetween. Even in the case that a conductive layer is provided on the side of the polarizing element of the one-side-protected polarizing film, which has the transparent protective film on only one surface of the polarizing element, decoloration of the end part of the polarizing element in a humidified environment can be suppressed.

Description

Polarizing film with adhesive layer and image display device

The present invention relates to a polarizing film with an adhesive layer. The present invention also relates to an image display panel and an image display device to which the polarizing film with an adhesive layer is applied.

An image display panel, for example, a liquid crystal panel used in a liquid crystal display device or the like, usually has polarizing films laminated on both sides of a liquid crystal cell formed of a liquid crystal layer disposed between a pair of transparent substrates with an adhesive layer interposed therebetween. Has been done. On the other hand, in the production of an image display panel, when the pressure-sensitive adhesive layer-attached polarizing film is attached to a liquid crystal cell, the release film is peeled off from the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached polarizing film. Static electricity is generated by peeling. The static electricity generated in this way affects the alignment of the liquid crystal layer inside the liquid crystal display panel, for example, and causes a defect. The generation of static electricity can be suppressed by, for example, forming an antistatic layer on the outer surface of the polarizing film.

For example, in order to suppress the above-mentioned generation of static electricity, an antistatic layer (conductive layer) containing a water-soluble or water-dispersible conductive polymer is provided on at least one surface of an optical film (for example, a polarizing film), and the antistatic layer is provided. There has been proposed an antistatic optical film with a pressure-sensitive adhesive layer in which a pressure-sensitive adhesive layer is laminated (Patent Document 1). It is also known that generation of static electricity can be suppressed by adding an ionic compound as an antistatic agent to the pressure-sensitive adhesive (Patent Document 2).

JP 2004-338379 A JP, 2009-251281, A

According to the polarizing film having the antistatic layer described in Patent Documents 1 and 2, generation of static electricity can be suppressed. However, when the antistatic layer formed of the conductive polymer described in Patent Document 1 is directly formed on the polarizer of the one-sided protective polarizing film, the conductive polymer adversely affects the polarizer and the polarized light is generated in a humid environment. It turned out that the edge of the child was discolored. Further, when the pressure-sensitive adhesive layer containing the antistatic agent described in Patent Document 2 is applied to the polarizer of the one-sided protective polarizing film, the antistatic agent penetrates into the inside of the polarizer in a humidified environment to cause polarization. It has been found that there is a problem that the antistatic function of the pressure-sensitive adhesive layer deteriorates in addition to the decolorization of the edges of the child.

The present invention, even when a conductive layer is provided on the side of the polarizer of the one-sided protective polarizing film having a transparent protective film only on one side of the polarizer, in a humid environment, suppresses decolorization of the end portion of the polarizer. An object of the present invention is to provide a pressure-sensitive adhesive layer-attached polarizing film.

Another object of the present invention is to provide an image display panel and an image display device to which the polarizing film with an adhesive layer is applied.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found the following polarizing film with an adhesive layer and completed the present invention.

That is, the present invention is
A polarizing film with an adhesive layer having a polarizing film and an adhesive layer,
The polarizing film has a polarizer, a transparent protective film only on one side of the polarizer, and a conductive layer on the other side of the polarizer via a transparent layer having a thickness of 10 μm or less directly formed on the polarizer. And a pressure-sensitive adhesive layer-attached polarizing film, wherein the pressure-sensitive adhesive layer is provided via the conductive layer.

In the polarizing film with the pressure-sensitive adhesive layer, a cured product of a forming material containing a urethane prepolymer, which is a reaction product of an isocyanate compound and a polyhydric alcohol, can be used as the transparent layer. As the isocyanate compound, it is preferable to use at least one selected from tolylene diisocyanate and diphenylmethane diisocyanate.

In the pressure-sensitive adhesive layer-attached polarizing film, the transparent layer may contain an epoxy resin.

In the polarizing film with a pressure-sensitive adhesive layer, in the transparent layer,
(A) An acrylic monomer in an amount of more than 50 parts by weight, and the following general formula (1) in an amount of more than 0 parts by weight and less than 50 parts by weight:

(In the formula, X is a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group. It represents a functional group containing at least one reactive group selected, and R ¹ and R ² are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or a substituent. Represents an optionally substituted aryl group or a heterocyclic group optionally having a substituent, and R ¹ and R ² may be linked to each other to form a ring) A polymer obtained by polymerizing and
A resin composition comprising (b) an epoxy resin,
A polymer in which the content ratio of the polymer (a) to the epoxy resin (b) is 95:5 to 60:40 or 40:60 to 1:99 by weight can be used.

The functional group represented by X in the general formula (1) is
General formula (2): ZY- (wherein Z is a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde. Group and a functional group containing at least one reactive group selected from the group consisting of a carboxyl group, and Y represents an organic group).

In the pressure-sensitive adhesive layer-attached polarizing film, the conductive layer preferably has a thickness of 1 μm or less.

In the pressure-sensitive adhesive layer-attached polarizing film, the conductive layer preferably contains a conductive polymer.

In the pressure-sensitive adhesive layer-attached polarizing film, the conductive layer preferably contains at least one selected from polythiophene, polyaniline, and carbon nanotube.

In the polarizing film with a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A) can be used.

In the polarizing film with a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A) and an ionic compound (B) can be used.

In the pressure-sensitive adhesive layer-attached polarizing film, the (meth)acrylic polymer (A) preferably contains an alkyl (meth)acrylate (a1) and an amide group-containing monomer (a2) as monomer units.

In the pressure-sensitive adhesive layer-attached polarizing film, the amide group-containing monomer (a2) is preferably an N-vinyl group-containing lactam monomer.

In the pressure-sensitive adhesive layer-attached polarizing film, the amide group-containing monomer (a2) is preferably contained as a monomer unit in the (meth)acrylic polymer (A) in an amount of 0.1% by weight or more.

In the pressure-sensitive adhesive layer-attached polarizing film, it is preferable that the ionic compound (B) is an alkali metal salt and the pressure-sensitive adhesive layer has a surface resistance value of 1×10 ¹⁰ to 1×10 ¹² Ω/□. .. Further, it is preferable that the ionic compound (B) is an organic cation-anion salt and the pressure-sensitive adhesive layer has a surface resistance value of 1×10 ⁸ to 1×10 ¹⁰ Ω/□.

In the pressure-sensitive adhesive layer-attached polarizing film, the ionic compound (B) is preferably contained in an amount of 0.01 parts by weight or more based on 100 parts by weight of the (meth)acrylic polymer (A).

In the polarizing film with an adhesive layer, it is suitable when the transparent protective film is a cellulose resin film or a (meth)acrylic resin film.

The present invention also relates to an image display panel comprising the above polarizing film with an adhesive layer. The image display panel can be applied to a liquid crystal cell having a touch sensing function, which has a liquid crystal layer and a touch sensor unit, and an adhesive layer of the polarizing film with an adhesive layer attached to the liquid crystal cell.

The present invention also relates to an image display device including the image display panel.

The polarizing film used for the pressure-sensitive adhesive layer-attached polarizing film of the present invention is a one-sided protective polarizing film having a transparent protective film on only one side of the polarizer, which is advantageous in terms of thinning and cost reduction. On the other hand, since the surface of the one-sided protective polarizing film that does not have the transparent protective film has the conductive layer, it is possible to suppress the generation of static electricity. Further, since the conductive layer is provided on the polarizer through the transparent layer, the conductive layer does not directly affect the polarizer, and decolorization of the end portion of the polarizer in a humid environment is prevented. Can be suppressed.

Further, the conductive layer is provided with a pressure-sensitive adhesive layer, but in the case where the composition is prepared by adding an ionic compound to the pressure-sensitive adhesive layer, the antistatic performance is improved by both the conductive layer and the pressure-sensitive adhesive layer. Can be improved. Furthermore, even in the case where the ionic compound is added to the pressure-sensitive adhesive layer, the transparent layer suppresses the segregation of the ionic compound contained in the pressure-sensitive adhesive layer to the polarizer, so that the humid environment It is possible to suppress an increase in the resistance value of the pressure-sensitive adhesive layer even below.

As described above, according to the pressure-sensitive adhesive layer-attached polarizing film of the present invention, it is possible to suppress deterioration of the optical reliability of the polarizer even though the one-sided protective polarizing film is used, and it is thin and has good optical reliability. It is possible to provide a polarizing film with a pressure-sensitive adhesive layer, which has excellent antistatic properties over a long period of time.

It is sectional drawing which shows an example of the polarizing film with an adhesive layer of this invention. It is sectional drawing which shows an example of the liquid crystal panel with a touch sensing function using the polarizing film with an adhesive layer of this invention. It is sectional drawing which shows an example of the liquid crystal panel with a touch sensing function using the polarizing film with an adhesive layer of this invention. It is sectional drawing which shows an example of the liquid crystal panel with a touch sensing function using the polarizing film with an adhesive layer of this invention.

The polarizing film with an adhesive layer of the present invention is shown in FIG. 1, for example. As shown in FIG. 1, the polarizing film 1 with an adhesive layer has a polarizer a, a transparent protective film b only on one side of the polarizer a, and a transparent layer on the other side of the polarizer a. The piece protective polarizing film 11 having c is used. The transparent layer c, the conductive layer d, and the adhesive layer 21 are provided in this order on the one-sided protective polarizing film 11. It is preferable that the transparent layer c is directly provided on the polarizer a in terms of suppressing an increase in water content of the polarizer under a high temperature and high humidity environment. The transparent layers c and d will be described later.

<Polarizing film with adhesive layer>
First, each member which comprises the polarizing film with an adhesive layer of this invention is demonstrated.

The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene/vinyl acetate copolymer partially saponified film, and dichroism of iodine or dichroic dye. Examples include polyene-oriented films such as those obtained by adsorbing a substance and uniaxially stretched, polyvinyl alcohol dehydrated products, polyvinyl chloride dehydrochlorinated products, and the like. Among these, a polarizer made of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

Also, a thin polarizer having a thickness of 10 μm or less can be used as the polarizer. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. It is preferable that such a thin polarizer has little thickness unevenness, excellent visibility, and excellent durability due to small dimensional change, and that the thickness of the polarizing film can be reduced.

As the material forming the transparent protective film, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. is used. Specific examples of such a thermoplastic resin include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, and cyclic resins. Examples thereof include polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. A transparent protective film is attached to one side of the polarizer with an adhesive layer, while a transparent protective film is attached to the other side as a (meth)acrylic type, urethane type, acrylic urethane type, epoxy type, or silicone type. A thermosetting resin such as a system or an ultraviolet curable resin can be used.

As the material of the transparent protective film, a cellulose resin or a (meth)acrylic resin is preferable because the fluctuation of the surface resistance value of the pressure-sensitive adhesive layer can be controlled to be small. As the (meth)acrylic resin, it is preferable to use a (meth)acrylic resin having a lactone ring structure. Examples of the (meth)acrylic resin having a lactone ring structure include JP-A-2000-230016, JP-A-2001-151814, JP-A-2002-120326, JP-A-2002-254544, and JP-A-2005. Examples thereof include (meth)acrylic resins having a lactone ring structure described in Japanese Patent No. 146084. In particular, the cellulose resin is preferable to the (meth)acrylic resin because it is more effective in suppressing the polarizer crack, which is a problem in the one-sided protective polarizing film.

A functional layer such as a hard coat layer, an antireflection layer, a sticking prevention layer, a diffusion layer or an antiglare layer can be provided on the surface of the transparent protective film to which the polarizer is not adhered.

The adhesive used for bonding the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent, and various types of water-based, solvent-based, hot-melt-based, radical-curable, and cation-curable types are used. However, a water-based adhesive or a radical curable adhesive is preferable.

<Transparent layer>
The transparent layer will be described in detail below.

The thickness of the transparent layer is preferably 10 μm or less, more preferably 5 μm or less, and further preferably 3 μm or less from the viewpoints of thinning and optical reliability, and further 1. It is preferably 5 μm or less, and more preferably 1 μm or less. If the transparent layer is too thick, the thickness of the polarizing film becomes large, and further, the optical reliability of the polarizer may be deteriorated. On the other hand, the thickness of the transparent layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, further preferably 0.3 μm or more, from the viewpoint of suppressing the fluctuation ratio of the surface resistance value of the pressure-sensitive adhesive layer. Is preferred.

As the material forming the transparent layer, a material having transparency and capable of suppressing the influence of the conductive layer on the polarizer can be used. Examples of such a material include a forming material containing a urethane prepolymer (a) which is a reaction product of an isocyanate compound and a polyhydric alcohol.

As the isocyanate compound, for example, a polyfunctional isocyanate compound is preferable, and specifically, a polyfunctional aromatic isocyanate compound, an alicyclic isocyanate compound, an aliphatic isocyanate compound, or a dimer thereof can be mentioned.

Examples of the polyfunctional aromatic isocyanate compound include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4 , 4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate, methylenebis 4-phenyl isocyanate, p-phenylene diisocyanate and the like.

Examples of the polyfunctional alicyclic isocyanate compound include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-bisisocyanatomethylcyclohexane, isophorone diisocyanate, and hydrogen. Examples thereof include added diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate and hydrogenated tetramethyl xylylene diisocyanate.

Examples of the polyfunctional aliphatic isocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4. 4-trimethylhexamethylene diisocyanate and the like can be mentioned.

Further, examples of the polyfunctional isocyanate compound include those having three or more isocyanate groups such as tris(6-incyanate hexyl) isocyanurate.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl- 1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2- Examples thereof include methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol and polypropylene glycol.

In the present invention, as the urethane prepolymer (a), a rigid structure in which a cyclic structure (benzene ring, cyanurate ring, isocyanurate ring, etc.) occupies a large proportion in the structure is used in the present invention. preferable. For example, the polyfunctional isocyanate compounds may be used alone or in combination of two or more, and aromatic isocyanate compounds are preferable from the viewpoint of suppressing water contamination in the polarizer. Other polyfunctional isocyanate compounds can be used in combination with the aromatic isocyanate compound. Particularly, it is preferable to use at least one selected from tolylene diisocyanate and diphenylmethane diisocyanate as the isocyanate compound among the aromatic isocyanate compounds.

As the urethane prepolymer (a), trimethylolpropane-tri-tolylene isocyanate and trimethylolpropane-tri-diphenylmethane diisocyanate are preferably used. The urethane prepolymer (a) is a compound having a terminal isocyanate group, and can be obtained, for example, by mixing an isocyanate compound and a polyhydric alcohol, stirring and reacting them. Usually, it is preferable to mix the isocyanate compound and the polyhydric alcohol so that the isocyanate group becomes excessive with respect to the hydroxyl group of the polyhydric alcohol.

The urethane prepolymer (a) may have a terminal isocyanate group with a protecting group. Protecting groups include oximes and lactams. When the isocyanate group is protected, the protective group is dissociated from the isocyanate group by heating and the isocyanate group reacts.

The forming material for forming the transparent layer may contain, in addition to the urethane prepolymer (a), a compound (b) having at least two functional groups having active hydrogen having reactivity with an isocyanate group. Examples of the functional group having active hydrogen having reactivity with an isocyanate group include a hydroxyl group and an amino group. As the number of functional groups having active hydrogen contained in the compound (b) increases, the number of reaction points with the isocyanate groups of the urethane prepolymer (a) increases and a cured product is easily formed. Therefore, the number of functional groups is 3 The above is preferable.

The compound (b) preferably has a molecular weight divided by the number of the functional groups of 350 or less. By thus defining the relationship between the molecular weight and the number of functional groups, the reactivity between the compound (b) and the isocyanate group of the urethane prepolymer (a) can be ensured.

The molecular weight of the compound (b) is preferably 1000 or less. The compound (b) having a molecular weight in the range of 1,000 or less is preferable in terms of compatibility with the urethane prepolymer (a) when the forming material is prepared as a solution.

Examples of the compound (b) include polyhydric alcohols, polyvalent amines, compounds having a hydroxyl group and an amino group in the molecule, and the like.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl- 1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2- Bifunctional alcohols such as methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, polypropylene glycol; trifunctional alcohols such as glycerin and trimethylolpropane; tetrafunctional alcohols such as pentaerythritol, hexanetriol and sorbitol Alcohol and the like; in addition, alkylene oxide (for example, propylene oxide) adducts of the polyhydric alcohols such as polyoxypropylene glyceryl ether, polyoxypropylene trimethylol propane ether, and polyoxypropylene sorbitol ether, and the like.

Examples of the polyvalent amine include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, dimerdiamine and the like.

Examples of the compound having a hydroxyl group and an amino group in the molecule include 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxy. Diamines having a hydroxyl group in the molecule such as propylethylenediamine and di-2-hydroxypropylethylenediamine;
Alkanolamines such as ethanolamine, diethanolamine and triethanolamine can be mentioned.

As the compound (b), it is preferable to use a polyhydric alcohol from the viewpoint of preventing the deterioration of the optical reliability of the polarizer. Particularly, trimethylolpropane is preferable from the viewpoint of reactivity with the urethane prepolymer (a). preferable.

The forming material contains the urethane prepolymer (a) as a main component. The urethane prepolymer (a) preferably contains 50% by weight or more of the solid content of the forming material.

The compounding ratio of the compound (b) to the urethane prepolymer (a) is 5% by weight or more based on the total 100% by weight (solid content ratio) of the urethane prepolymer (a) and the compound (b). Preferably. The compounding ratio of the compound (b) is preferably 10% by weight or more from the viewpoint of improving the film strength. On the other hand, when the compounding ratio of the compound (b) is increased, the optical reliability of the polarizer may be deteriorated. Therefore, the compounding ratio of the compound (b) is 80% by weight or less, and further 50% by weight or less. Preferably.

The above-mentioned forming material can use a reaction catalyst to further increase the reactivity of the isocyanate group. The reaction catalyst is not particularly limited, but a tin-based catalyst or an amine-based catalyst is preferable. As the reaction catalyst, one kind or two or more kinds can be used. The amount of the reaction catalyst used is usually 5 parts by weight or less based on 100 parts by weight of the urethane prepolymer (a). When the amount of the reaction catalyst is large, the crosslinking reaction rate is increased and foaming of the forming material occurs. Even if a forming material after foaming is used, sufficient adhesiveness cannot be obtained. Usually, when a reaction catalyst is used, it is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 4 parts by weight.

A reaction catalyst can be used to further increase the reactivity of the isocyanate group. The reaction catalyst is not particularly limited, but a tin-based catalyst or an amine-based catalyst is preferable. As the reaction catalyst, one kind or two or more kinds can be used. The amount of the reaction catalyst used is usually 5 parts by weight or less with respect to 100 parts by weight of the urethane prepolymer. When the amount of the reaction catalyst is large, the crosslinking reaction rate is increased and foaming of the forming material occurs. Even if a forming material after foaming is used, sufficient adhesiveness cannot be obtained. Usually, when a reaction catalyst is used, it is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 4 parts by weight.

As the tin catalyst, both inorganic and organic catalysts can be used, but organic catalysts are preferred. Examples of the inorganic tin-based catalyst include stannous chloride and stannic chloride. The organic tin-based catalyst preferably has at least one organic group such as an aliphatic group or an alicyclic group having a skeleton such as a methyl group, an ethyl group, an ether group, or an ester group. Examples thereof include tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin trichloride, trimethyltin hydroxide, dimethyltin dichloride and dibutyltin dilaurate.

Also, the amine catalyst is not particularly limited. For example, those having at least one organic group such as alicyclic group such as quinoclidine, amidine and diazabicycloundecene are preferable. Other examples of amine-based catalysts include triethylamine and the like. Examples of reaction catalysts other than those mentioned above include cobalt naphthenate and benzyltrimethylammonium hydroxide.

The forming material is usually used as a solution containing the urethane prepolymer (a) and the compound (b). The solution may be a solvent system or an aqueous system such as an emulsion, a colloidal dispersion or an aqueous solution.

The organic solvent is not particularly limited as long as it does not have a functional group having active hydrogen having reactivity with an isocyanate group and uniformly dissolves the urethane prepolymer (a) and the compound (b) constituting the forming material. Absent. The organic solvent may be used alone or in combination of two or more. As the organic solvent, different solvents can be used for the urethane prepolymer (a) and the compound (b). In this case, the forming material can be prepared by mixing each solution after preparing each solution. Further, the viscosity of the forming material can be adjusted by further adding an organic solvent to the prepared forming material. Further, even in the case of a solvent-based solution dissolved in an organic solvent, alcohols, water and the like exemplified below can be contained as a solvent.

Organic solvents include aromatic hydrocarbons such as toluene and xylene); esters such as ethyl acetate and butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane, cyclohexane and methylcyclohexane; 1,2-dichloroethane And the like; ethers such as tert-butyl methyl ether; ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, and acetylacetone; and the like.

In the case of using an aqueous system, for example, alcohols such as n-butyl alcohol and isopropyl alcohol, and ketones such as acetone can be mixed. When it is made water-based, a dispersant is used, or urethane prepolymer is used as a functional group having low reactivity with isocyanate groups such as carboxylate, sulfonate, and quaternary ammonium salt, and water dispersibility such as polyethylene glycol. This can be done by introducing the components.

<Epoxy resin>
An epoxy resin can be used as a material for forming the transparent layer.
Any appropriate epoxy resin can be used as the epoxy resin. An epoxy resin having an aromatic ring is preferably used as the epoxy resin. By using the epoxy resin, the surface resistance value of the pressure-sensitive adhesive layer can be prevented from changing over time, the adhesiveness with the polarizer can be further improved, and color loss from the end portion of the polarizer can be prevented. Further, when the pressure-sensitive adhesive layer is formed on the transparent layer, the anchoring force of the pressure-sensitive adhesive layer can be improved. Examples of the epoxy resin having an aromatic ring include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin and other bisphenol type epoxy resins; phenol novolac epoxy resin, cresol novolac epoxy resin, hydroxybenzaldehyde phenol novolac. Novolak type epoxy resin such as epoxy resin; polyhydroxy type epoxy resin such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, epoxidized polyvinylphenol, naphthol type epoxy resin, naphthalene type epoxy resin, biphenyl type Examples thereof include epoxy resin. Preferably, a bisphenol A type epoxy resin, a biphenyl type epoxy resin, and a bisphenol F type epoxy resin are used. By using these epoxy resins, color loss from the end of the polarizer can be further prevented. Only one epoxy resin may be used, or two or more epoxy resins may be used in combination.

The weight average molecular weight (Mw) of the epoxy resin is preferably 20,000 or more, more preferably 30,000 or more, and further preferably 37,000 or more. When the weight average molecular weight of the epoxy resin is within the above range, it is possible to further prevent color loss from the end portion of the polarizer. The weight average molecular weight can be measured, for example, by GPC.

The material for forming the transparent layer may be, for example, an acrylic monomer in an amount of more than 50 parts by weight and a monomer represented by the following general formula (1) in an amount of more than 0 parts by weight and less than 50 parts by weight. It is possible to use a composition containing a polymer (a) (hereinafter, also referred to as a polymer (a)) obtained by polymerizing the above and an epoxy resin (b). The content ratio of the polymer (a) and the epoxy resin (b) is preferably 95:5 to 60:40, or 40:60 to 1:99 by weight.

(In the formula, X is a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group. It represents a functional group containing at least one reactive group selected, and R ¹ and R ² are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or a substituent. Represents an optionally substituted aryl group or an optionally substituted heterocyclic group, and R ¹ and R ² may be linked to each other to form a ring).

The content ratio of the polymer (a) and the epoxy resin (b) in the composition is 95:5 to 60:40 by weight, or 40:60 to 1:99. When the content ratio of the polymer (a) and the epoxy resin (b) is within the above range, the surface resistance value of the pressure-sensitive adhesive layer is prevented from changing over time, the adhesiveness with the polarizer is excellent, and the end of the polarizer is obtained. A resin composition for a transparent layer that can prevent color loss from a part is obtained. Further, when the content ratio of the polymer (a) and the epoxy resin (b) is within the above range, the anchoring force of the pressure-sensitive adhesive layer can be improved when the pressure-sensitive adhesive layer is formed on the transparent layer. As a result, it is possible to obtain a polarizing plate (transparent layer-attached one-sided protective polarizing film) that has both the adhesion between the polarizer and the transparent layer and the anchoring force of the pressure-sensitive adhesive layer formed on the transparent layer. The content ratio of the polymer (a) and the epoxy resin (b) is preferably 95:5 to 80:20, or 20:80 to 5:95, and more preferably 90:10 to, by weight. 70:30 or 30:70 to 10:90. The closer the content ratio of the polymer (a) and the epoxy resin (b) is to the equal portion (50:50), the more likely the protective layer is whitened.

<Polymer (a)>
The polymer (a) is obtained by polymerizing more than 50 parts by weight of an acrylic monomer and more than 0 parts by weight and less than 50 parts by weight of the monomer represented by the general formula (1). can get.

The polymer (a) typically has a structure represented by the following formula. By polymerizing the monomer represented by the general formula (1) and an acrylic monomer component, the polymer (a) has a substituent containing a boron in the side chain (for example, repeating k in the following formula). Units). This can improve the adhesion between the polarizer and the layer (transparent layer) formed using the resin composition. The substituent containing boron may be continuously contained in the polymer or may be randomly contained therein.
The polymer (a) may be used alone or in combination of two or more kinds.

(In the formula, R ⁶ represents an arbitrary functional group, and j and k represent an integer of 1 or more).

The weight average molecular weight of the polymer (a) is preferably 10,000 or more, more preferably 20,000 or more, further preferably 35,000 or more, and particularly preferably 50,000 or more. .. The weight average molecular weight of the polymer (a) is preferably 250,000 or less, more preferably 200,000 or less, still more preferably 150,000 or less. When the weight average molecular weight of the polymer (a) is in the above range, the crack resistance of the layer (transparent layer) formed using the resin composition can be improved. The weight average molecular weight can be measured, for example, by GPC (solvent: dimethylformamide (DMF)).

The glass transition temperature of the polymer (a) is preferably 50° C. or higher, more preferably 60° C. or higher, even more preferably 80° C. or higher. The glass transition temperature of the polymer (a) is preferably 300°C or lower. When the glass transition temperature is in the above range, the crack resistance of the layer (transparent layer) formed using the resin composition can be improved.

The polymer (a) includes an acrylic monomer in an amount of more than 50 parts by weight, an amount of the monomer represented by the formula (1) in an amount of more than 0 parts by weight and less than 50 parts by weight, and a polymerization initiator. It can be obtained by polymerizing the monomer composition containing the other monomer by any suitable polymerization method. Solution polymerization is preferably used as the polymerization method. By polymerizing the polymer (a) by solution polymerization, a higher molecular weight polymer can be obtained.

≪Acrylic monomer≫
Any appropriate acrylic monomer can be used as the acrylic monomer. For example, a (meth)acrylic acid ester-based monomer having a linear or branched structure and a (meth)acrylic acid ester-based monomer having a cyclic structure may be mentioned. In the present specification, (meth)acrylic refers to acrylic and/or methacrylic.

Examples of the (meth)acrylic acid ester-based monomer having a linear or branched structure include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and (meth)acrylic acid. Examples include isopropyl, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, methyl 2-ethylhexyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. .. Preferably, methyl (meth)acrylate is used. The (meth)acrylic acid ester-based monomer may be used alone or in combination of two or more kinds.

Examples of the (meth)acrylic acid ester-based monomer having a cyclic structure include cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, and ( Dicyclopentenyl (meth)acrylate, Dicyclopentenyloxyethyl (meth)acrylate, Dicyclopentanyl (meth)acrylate, Biphenyl (meth)acrylate, o-biphenyloxyethyl (meth)acrylate, o-biphenyloxyethoxy Ethyl (meth)acrylate, m-biphenyloxyethyl acrylate, p-biphenyloxyethyl (meth)acrylate, o-biphenyloxy-2-hydroxypropyl (meth)acrylate, p-biphenyloxy-2-hydroxypropyl (meth)acrylate , M-biphenyloxy-2-hydroxypropyl(meth)acrylate, N-(meth)acryloyloxyethyl-o-biphenyl=carbamate, N-(meth)acryloyloxyethyl-p-biphenyl=carbamate, N-(meth) Examples thereof include acryloyloxyethyl-m-biphenyl carbamate, a biphenyl group-containing monomer such as o-phenylphenol glycidyl ether acrylate, terphenyl (meth)acrylate, o-terphenyloxyethyl (meth)acrylate and the like. Preferably, 1-adamantyl (meth)acrylate and dicyclopentanyl (meth)acrylate are used. By using these monomers, a polymer having a high glass transition temperature can be obtained. These monomers may be used alone or in combination of two or more. In addition, in this specification, (meth)acryloyl means an acryloyl group and/or a methacryloyl group.

Alternatively, a silsesquioxane compound having a (meth)acryloyl group may be used instead of the (meth)acrylic acid ester-based monomer. By using the silsesquioxane compound, an acrylic polymer having a high glass transition temperature can be obtained. It is known that the silsesquioxane compound has various skeleton structures, for example, a skeleton structure such as a cage structure, a ladder structure, and a random structure. The silsesquioxane compound may have only one type of these structures, or may have two or more types of these structures. The silsesquioxane compound may be used alone or in combination of two or more kinds.

As the silsesquioxane compound having a (meth)acryloyl group, for example, MAC grade and AC grade of SQ series of Toagosei Co., Ltd. can be used. The MAC grade is a silsesquioxane compound containing a methacryloyl group, and specific examples thereof include MAC-SQ TM-100, MAC-SQ SI-20, MAC-SQ HDM and the like. AC grade is a silsesquioxane compound containing an acryloyl group, and specific examples thereof include AC-SQ TA-100 and AC-SQ SI-20.

Acrylic monomer is used in excess of 50 parts by weight. The acrylic monomer is used so that the total amount of the acrylic monomer and the monomer represented by the general formula (1) is 100 parts by weight.

<<Monomer represented by the general formula (1)>>
By using the monomer represented by the general formula (1), a substituent containing boron is introduced into the side chain of the polymer (a). Therefore, the adhesion between the polarizer typically composed of the PVA-based resin and the layer (transparent layer) formed using the resin composition can be improved. In addition, the water resistance of the layer (transparent layer) itself formed using the resin composition is also improved, and color loss from the end portion of the polarizer can be prevented. The monomers may be used alone or in combination of two or more.

As the above-mentioned aliphatic hydrocarbon group, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, and a cyclic alkyl group having 3 to 20 carbon atoms which may have a substituent. And an alkenyl group having 2 to 20 carbon atoms. Examples of the aryl group include a phenyl group having 6 to 20 carbon atoms which may have a substituent and a naphthyl group having 10 to 20 carbon atoms which may have a substituent. Examples of the heterocyclic group include a 5-membered ring group and a 6-membered ring group containing at least one hetero atom which may have a substituent. In addition, R ¹ and R ² may be linked to each other to form a ring. R ¹ and R ² are preferably a hydrogen atom or a linear or branched alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.

The reactive group contained in the functional group represented by X is a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group. , And at least one selected from the group consisting of carboxyl groups. Preferably, the reactive groups are (meth)acrylic groups and/or (meth)acrylamide groups. By having these reactive groups, the adhesion between the polarizer and the layer (transparent layer) formed using the resin composition can be improved.

In one embodiment, the functional group represented by X is represented by the general formula (2): ZY— (wherein Z is a vinyl group, a (meth)acryl group, a styryl group, a (meth)acrylamide group. Represents a functional group containing at least one reactive group selected from the group consisting of a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group, and Y represents an organic group. It is preferable that it is a functional group represented by these. The organic group specifically means an organic group having 1 to 20 carbon atoms which may have a substituent, and more specifically, for example, having a substituent having 1 to 20 carbon atoms. Optionally linear or branched alkylene group, cyclic alkylene group having 3 to 20 carbon atoms which may have a substituent, phenylene group having 6 to 20 carbon atoms which may have a substituent, and 10 to 10 carbon atoms. Examples thereof include a naphthylene group which may have 20 substituents.

The following compounds can be specifically used as the monomer represented by the general formula (1).

As the monomer represented by the general formula (1), in addition to the above-exemplified compounds, hydroxyethyl acrylamide and boric acid ester, methylol acrylamide and boric acid ester, hydroxyethyl acrylate and boric acid ester, and An ester of (meth)acrylate and boric acid can be exemplified, such as an ester of hydroxybutyl acrylate and boric acid.

The content of the monomer represented by the general formula (1) is more than 0 parts by weight and less than 50 parts by weight. It is preferably 0.01 parts by weight or more and less than 50 parts by weight, more preferably 0.05 parts by weight to 20 parts by weight, and further preferably 0.1 parts by weight to 10 parts by weight. When the content of the monomer exceeds 50 parts by weight, color loss may easily occur from the edges.

<<Polymerization initiator>>
Any appropriate polymerization initiator can be used as the polymerization initiator. Examples thereof include peroxides such as benzoyl peroxide, lauroyl peroxide and sodium peroxide; hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; azo compounds such as azobisisobutyronitrile; and the like. As the polymerization initiator, only one kind may be used, or two or more kinds may be used.

The content of the polymerization initiator may be any appropriate amount. The content of the polymerization initiator is preferably 0.1 part by weight to 5 parts by weight, more preferably 0.3 part by weight to 2 parts by weight.

<< Polymerization method >>
As described above, the polymer (a) is preferably obtained by solution polymerization of a monomer component such as an acrylic monomer and a monomer represented by the general formula (1). Any appropriate solvent can be used as the solvent used in the solution polymerization. For example, water; alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, n-hexane; ester compounds such as ethyl acetate; ketones such as acetone and methyl ethyl ketone. Compounds: Cyclic ether compounds such as tetrahydrofuran and dioxane, etc. may be mentioned. These solvents may be used alone or in combination of two or more. Moreover, you may use together an organic solvent and water.

The polymerization reaction can be performed at any appropriate temperature and time. For example, the polymerization reaction can be carried out in the range of 50°C to 100°C, preferably 60°C to 80°C. The reaction time is, for example, 1 hour to 8 hours, preferably 3 hours to 5 hours.

<Epoxy resin (b)>
Any appropriate epoxy resin can be used as the epoxy resin (b). An epoxy resin having an aromatic ring is preferably used as the epoxy resin (b). By using an epoxy resin having an aromatic ring as the epoxy resin (b), it is possible to obtain a resin composition for a transparent layer which is more excellent in adhesiveness with a polarizer and can prevent color loss from the end portion of the polarizer. .. Further, when the pressure-sensitive adhesive layer is formed on the transparent layer, the anchoring force of the pressure-sensitive adhesive layer can be improved. Examples of the epoxy resin having an aromatic ring include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin and other bisphenol type epoxy resins; phenol novolac epoxy resin, cresol novolac epoxy resin, hydroxybenzaldehyde phenol novolac. Novolak type epoxy resin such as epoxy resin; polyhydroxy type epoxy resin such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, epoxidized polyvinylphenol, naphthol type epoxy resin, naphthalene type epoxy resin, biphenyl type Examples thereof include epoxy resin. Preferably, a bisphenol A type epoxy resin, a biphenyl type epoxy resin, and a bisphenol F type epoxy resin are used. By using these epoxy resins, color loss from the end of the polarizer can be further prevented. Only one epoxy resin may be used, or two or more epoxy resins may be used in combination.

The epoxy resin (b) preferably has a weight average molecular weight (Mw) of 20,000 or more, more preferably 30,000 or more, still more preferably 37,000 or more. When the weight average molecular weight of the epoxy resin (b) is in the above range, it is possible to further prevent color loss from the end portion of the polarizer. The weight average molecular weight can be measured, for example, by GPC.

<Other ingredients>
The resin composition for a transparent layer may contain any appropriate other component in addition to the epoxy resin, the polymer (a) and the epoxy resin (b). Other components include, for example, a solvent and an additive. As the solvent, a solvent that can be used in solution polymerization of the polymer (a) may be used, or another solvent may be used. As the other solvent, ethyl acetate, toluene, methyl ethyl ketone, and cyclopentanone are preferably used. These solvents may be used alone or in combination of two or more.

Any appropriate additive can be used as the additive. For example, surfactants, ultraviolet absorbers, antioxidants, tackifiers and the like can be mentioned. As the additive, only one kind may be used, or two or more kinds may be used in combination. These additives can be used in any suitable amount.

<Method for preparing resin composition for transparent layer>
The transparent layer resin composition can be prepared by any appropriate method. For example, it can be prepared by mixing the polymer (a), the epoxy resin (b), and, if necessary, any appropriate additive in any appropriate solvent. When the polymer (a) is polymerized by solution polymerization, it may be prepared by adding the epoxy resin (b) and any appropriate additive to the polymer solution of the polymer (a) and mixing them. Good.

As a material for forming a transparent layer other than the forming material containing the urethane prepolymer (a), the forming material containing the epoxy resin, and the forming material of the composition containing the polymer (a) and the epoxy resin (b) Examples include cyanoacrylate-based forming materials, epoxy-based forming materials, urethane acrylate-based forming materials, and the like.

The formation of the transparent layer can be appropriately selected depending on the type of the forming material. For example, the transparent layer can be formed by applying the forming material to a polarizer or the like and then curing it. It can be obtained as a layer. Usually, it is carried out by forming a cured layer by drying at about 30 to 100° C., preferably at 50 to 80° C. for about 0.5 to 15 minutes after the coating. Further, when the forming material contains an isocyanate component, an annealing treatment is performed at about 30 to 100° C., preferably at 50 to 80° C. for about 0.5 to 24 hours in order to accelerate the reaction. You can

<Conductive layer>
The thickness of the conductive layer d is preferably 1 μm or less, more preferably 0.01 to 0.5 μm, from the viewpoint of the stability of the surface resistance value and the adhesiveness to the pressure-sensitive adhesive layer 21. The thickness is preferably 01 to 0.2 μm, more preferably 0.01 to 0.1 μm. Further, the surface resistance value of the conductive layer d is preferably 1×10 ⁸ to 1×10 ¹² Ω/□, from the viewpoint of the antistatic function, and 1×10 ⁸ to 1×10 ¹¹ Ω/□. Is more preferable, and further preferably 1×10 ⁸ to 1×10 ¹⁰ Ω.

The conductive layer can be formed from various antistatic agent compositions. As the antistatic agent forming the conductive layer, an ionic surfactant system, a conductive polymer, conductive fine particles, carbon nanotubes, etc. can be used.

Among these antistatic agents, conductive polymers and carbon nanotubes are preferably used from the viewpoints of optical properties, appearance, antistatic effect, and stability of antistatic effect when heated and humidified. In particular, conductive polymers such as polyaniline and polythiophene are preferably used. As the conductive polymer, those soluble in an organic solvent, water-soluble and water-dispersible can be appropriately used, but a water-soluble conductive polymer or a water-dispersible conductive polymer is preferably used. The water-soluble conductive polymer or the water-dispersible conductive polymer can be prepared as an aqueous solution or an aqueous dispersion of the coating liquid when forming the antistatic layer, the coating liquid does not need to use a non-aqueous organic solvent, This is because the deterioration of the optical film substrate due to the solvent can be suppressed. The aqueous solution or aqueous dispersion may contain an aqueous solvent in addition to water. For example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1-ethyl-1 Examples include alcohols such as -propanol, 2-methyl-1-butanol, n-hexanol and cyclohexanol.

The water-soluble conductive polymer or water-dispersible conductive polymer such as polyaniline or polythiophene preferably has a hydrophilic functional group in the molecule. Examples of the hydrophilic functional group include a sulfone group, an amino group, an amide group, an imino group, a quaternary ammonium salt group, a hydroxyl group, a mercapto group, a hydrazino group, a carboxyl group, a sulfate ester group, a phosphate ester group, or a salt thereof. Etc. By having a hydrophilic functional group in the molecule, it becomes easy to be dissolved in water or easily dispersed in water in the form of fine particles, so that the water-soluble conductive polymer or the water-dispersible conductive polymer can be easily prepared.

Examples of commercially available water-soluble conductive polymers include polyaniline sulfonic acid (manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight of 150,000 by polystyrene conversion) and the like. Examples of commercially available water-dispersible conductive polymers include polythiophene-based conductive polymers (trade name, Denatron series, manufactured by Nagase Chemtech).

As a material for forming the conductive layer, a binder component may be added together with the antistatic agent for the purpose of improving the film forming property of the antistatic agent, the adhesion to the optical film, and the like. When the antistatic agent is a water-based conductive polymer or water-dispersible conductive polymer aqueous material, a water-soluble or water-dispersible binder component is used. Examples of the binder, oxazoline group-containing polymer, polyurethane resin, polyester resin, acrylic resin, polyether resin, cellulose resin, polyvinyl alcohol resin, epoxy resin, polyvinylpyrrolidone, polystyrene resin, polyethylene glycol, Examples include pentaerythritol. Polyurethane resin, polyester resin, and acrylic resin are particularly preferable. These binders may be used alone or in combination of two or more as appropriate for their application.

The amount of the antistatic agent and the binder used depends on their types, but it is preferable to control the surface resistance value of the obtained conductive layer to be 1×10 ⁸ to 1×10 ¹² Ω/□.

<Adhesive layer>
The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive. As the pressure-sensitive adhesive, various pressure-sensitive adhesives can be used, for example, rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives, polyvinylpyrrolidone-based pressure-sensitive adhesives, Examples thereof include polyacrylamide adhesives and cellulose adhesives. An adhesive base polymer is selected according to the type of the adhesive. Among the pressure-sensitive adhesives, an acrylic pressure-sensitive adhesive is preferably used because it has excellent optical transparency, exhibits appropriate wettability, cohesiveness, and adhesive properties of adhesiveness and is excellent in weather resistance and heat resistance. It

The acrylic pressure-sensitive adhesive is prepared from a pressure-sensitive adhesive composition containing the (meth)acrylic polymer (A). Less than. The pressure-sensitive adhesive composition will be described.

The (meth)acrylic polymer (A) contains, as a monomer unit, an alkyl (meth)acrylate (a1) as a main component. In addition, (meth)acrylate refers to acrylate and/or methacrylate, and has the same meaning as (meth) of the present invention.

Examples of the alkyl (meth)acrylate constituting the main skeleton of the (meth)acrylic polymer (A) include linear or branched alkyl groups having 1 to 18 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an amyl group, a hexyl group, a cyclohexyl group, a heptyl group, a 2-ethylhexyl group, an isooctyl group, a nonyl group, and a decyl group. Examples thereof include a group, an isodecyl group, a dodecyl group, an isomyristyl group, a lauryl group, a tridecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group and an octadecyl group. These can be used alone or in combination. The average carbon number of these alkyl groups is preferably 3-9.

The weight ratio of the alkyl (meth)acrylate (a1) is 70% by weight or more in the weight ratio of all the constituent monomers (100% by weight) constituting the (meth)acrylic polymer (A) as a monomer unit. preferable. The weight ratio of the alkyl (meth)acrylate (a1) can be considered as the balance of the other copolymerization monomers. It is preferable to set the weight ratio of the alkyl (meth)acrylate (a1) within the above range in order to secure the adhesiveness.

In the (meth)acrylic polymer (A), in addition to the monomer unit of the alkyl (meth)acrylate (a1), a (meth)acryloyl group, a vinyl group or the like for the purpose of improving adhesiveness and heat resistance. One or more copolymerizable monomers having a polymerizable functional group having an unsaturated double bond can be introduced by copolymerization.

Examples of the copolymerizable monomer include functional group-containing monomers such as amide group-containing monomers, carboxyl group-containing monomers, and hydroxyl group-containing monomers. Among these, the amide group-containing monomer (a2) is suitable when the ionic compound (B) described below is blended.

In the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer, when the amide group introduced into the side chain in the (meth)acrylic polymer (A) as the base polymer is present, the amide group The presence of the composition prevents the surface resistance value of the pressure-sensitive adhesive layer adjusted by blending the ionic compound (B) from fluctuating and increasing even in a humid environment, and keeps it within a desired value range. It is preferable to Compatibility of the (meth)acrylic polymer (A) with the ionic compound (B) due to the presence of the amide group introduced as a functional group of the copolymerization monomer in the side chain of the (meth)acrylic polymer (A) Is expected to rise.

Further, the pressure-sensitive adhesive layer has a glass and a transparent conductive layer (ITO layer or the like) when an amide group introduced into a side chain in a (meth)acrylic polymer (A) which is a base polymer is present. It has good durability against any of the above, and it is possible to suppress the occurrence of peeling, floating, etc. in the state of being attached to the liquid crystal panel. Further, the durability can be satisfied even in a humid environment (after a humidification reliability test).

The amide group-containing monomer (a2) is a compound containing an amide group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Specific examples of the amide group-containing monomer (a2) include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide. , N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylol-N-propane(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide , Mercaptomethyl (meth)acrylamide, mercaptoethyl (meth)acrylamide and other acrylamide monomers; N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine and other N-acryloyl heterocycles Monomers: N-vinyl group-containing lactam monomers such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam. The amide group-containing monomer (a2) is preferable for suppressing an increase in surface resistance value over time (particularly in a humid environment) and satisfying durability. In particular, among the amide group-containing monomers (a2), particularly the N-vinyl group-containing lactam-based monomer suppresses an increase in the surface resistance value over time (especially in a humid environment), or a transparent conductive layer (touch). It is preferable in satisfying the durability against the sensor layer). Although not exemplified in the above, the amide group-containing monomer having a hydroxyl group tends to have improved conductivity in combination with the ionic compound (B), and when the use ratio increases, a polarizing film ( It is preferably not used because there is a problem in anchoring force with the optical film) and reworkability with the transparent conductive layer (touch sensor layer).

The weight ratio of the amide group-containing monomer (a2) is preferably 0.1% by weight or more from the viewpoint of suppressing an increase in the surface resistance value over time (particularly in a humid environment). The weight ratio is preferably 0.3% by weight or more, and more preferably 0.5% by weight or more. On the other hand, if the weight ratio is too large, the anchoring property to the base film such as the polarizing film tends to be lowered. Therefore, the weight ratio is preferably 35% by weight or less, and further 30% by weight or less. It is more preferably 25% by weight or less.

A carboxyl group-containing monomer is a compound that has a carboxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Specific examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and the like. Among the above-mentioned carboxyl group-containing monomers, acrylic acid is preferable from the viewpoint of copolymerizability, price and adhesive property.

A hydroxyl group-containing monomer is a compound that contains a hydroxyl group in its structure and also contains a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group. Specific examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 8-. Examples thereof include hydroxyalkyl (meth)acrylates such as hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl acrylate. Among the above-mentioned hydroxyl group-containing monomers, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferable, and 4-hydroxybutyl (meth)acrylate is particularly preferable, from the viewpoint of durability.

When the pressure-sensitive adhesive composition contains a crosslinking agent, the carboxyl group-containing monomer and the hydroxyl group-containing monomer become reaction points with the crosslinking agent. Since the carboxyl group-containing monomer and the hydroxyl group-containing monomer have high reactivity with the intermolecular crosslinking agent, they are preferably used for improving the cohesiveness and heat resistance of the obtained pressure-sensitive adhesive layer. Further, the carboxyl group-containing monomer is preferable from the viewpoint of achieving both durability and reworkability, and the hydroxyl group-containing monomer is preferable from the viewpoint of reworkability.

The above-mentioned weight ratio of the carboxyl group-containing monomer is preferably 2% by weight or less, more preferably 0.01 to 2% by weight, further preferably 0.05 to 1.5% by weight, further preferably 0.1. It is preferably 1 to 1% by weight, and most preferably 0.1 to 0.5% by weight. It is preferable in terms of durability that the weight ratio of the carboxyl group-containing monomer be 0.01% by weight or more. On the other hand, if it exceeds 2% by weight, it is not preferable from the viewpoint of reworkability.

The weight ratio of the hydroxyl group-containing monomer is preferably 3% by weight or less, more preferably 0.01 to 3% by weight, further preferably 0.1 to 2% by weight, and further 0.2 to 2% by weight is preferred. It is preferable that the weight ratio of the hydroxyl group-containing monomer is 0.01% by weight or more from the viewpoint of crosslinking the pressure-sensitive adhesive layer, durability and adhesive properties. On the other hand, if it exceeds 3% by weight, it is not preferable in terms of durability.

As the copolymerization monomer, for example, aromatic ring-containing (meth)acrylate can be used. The aromatic ring-containing (meth)acrylate is a compound containing an aromatic ring structure in its structure and a (meth)acryloyl group. Examples of the aromatic ring include a benzene ring, a naphthalene ring and a biphenyl ring.

Specific examples of the aromatic ring-containing (meth)acrylate include, for example, benzyl(meth)acrylate, phenyl(meth)acrylate, o-phenylphenol(meth)acrylate phenoxy(meth)acrylate, phenoxyethyl(meth)acrylate, phenoxypropyl. (Meth)acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide modified nonylphenol (meth)acrylate, ethylene oxide modified cresol (meth)acrylate, phenol ethylene oxide modified (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth) Those having a benzene ring such as acrylate, methoxybenzyl (meth)acrylate, chlorobenzyl (meth)acrylate, cresyl (meth)acrylate, and polystyryl (meth)acrylate; hydroxyethylated β-naphthol acrylate, 2-naphthoethyl (meth)acrylate , Those having a naphthalene ring such as 2-naphthoxyethyl acrylate and 2-(4-methoxy-1-naphthoxy)ethyl (meth)acrylate; those having a biphenyl ring such as biphenyl (meth)acrylate.

As the aromatic ring-containing (meth)acrylate, benzyl (meth)acrylate and phenoxyethyl (meth)acrylate are preferable, and phenoxyethyl (meth)acrylate is particularly preferable, from the viewpoint of adhesive properties and durability.

The weight ratio of the aromatic ring-containing (meth)acrylate is preferably 25% by weight or less, more preferably 3 to 25% by weight, further preferably 10 to 22% by weight, further 14 to 20% by weight. Is preferred. When the weight ratio of the aromatic ring-containing (meth)acrylate is 3% by weight or more, it is preferable for suppressing display unevenness. On the other hand, when it exceeds 25% by weight, uneven display is not sufficiently suppressed and durability tends to be deteriorated.

Specific examples of other copolymerizable monomers other than the above include acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; allylsulfonic acid, 2-(meth)acrylamide-2- Examples thereof include sulfonic acid group-containing monomers such as methyl propane sulfonic acid, (meth)acrylamide propane sulfonic acid and sulfopropyl (meth)acrylate; and phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate.

Further, alkylaminoalkyl(meth)acrylates such as aminoethyl(meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, t-butylaminoethyl(meth)acrylate; methoxyethyl(meth)acrylate, ethoxyethyl( Alkoxyalkyl (meth)acrylates such as (meth)acrylate; N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyoctamethylenesuccinimide, etc. Succinimide-based monomers; maleimide-based monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N- Examples of monomers for modification are also itaconimide-based monomers such as octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, and N-lauryl itaconimide.

Further, as a modifying monomer, vinyl-based monomers such as vinyl acetate and vinyl propionate; cyanoacrylate-based monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate; polyethylene glycol (meth). Glycol-based (meth)acrylates such as acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxy polypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth) ) Acrylate and (meth)acrylate monomers such as 2-methoxyethyl acrylate can also be used. Further, isoprene, butadiene, isobutylene, vinyl ether and the like can be mentioned.

Furthermore, examples of copolymerizable monomers other than the above include silane-based monomers containing a silicon atom. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane. , 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane and the like.

Further, as the copolymerization monomer, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neo Pentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate , Polyfunctional having two or more unsaturated double bonds such as (meth)acryloyl group and vinyl group such as esterification products of (meth)acrylic acid such as caprolactone-modified dipentaerythritol hexa(meth)acrylate and polyhydric alcohol (2) or more unsaturated double bonds such as (meth)acryloyl group and vinyl group as functional groups similar to the monomer component are added to the skeleton of the organic monomer, polyester, epoxy, urethane, etc., and polyester (meth)acrylate, epoxy ( It is also possible to use (meth)acrylate, urethane (meth)acrylate and the like.

The proportion of the other copolymerizable monomer in the (meth)acrylic polymer (A) is about 0 to 10% in the weight ratio of all the constituent monomers (100% by weight) of the (meth)acrylic polymer (A). Further, it is preferably about 0 to 7%, more preferably about 0 to 5%.

The (meth)acrylic polymer (A) of the present invention usually preferably has a weight average molecular weight of 1,000,000 to 2,500,000. Considering durability, particularly heat resistance, the weight average molecular weight is preferably 1.2 to 2,000,000. A weight average molecular weight of 1,000,000 or more is preferable in terms of heat resistance. When the weight average molecular weight is more than 2.5 million, the pressure sensitive adhesive tends to be hard and peeling easily occurs. The weight average molecular weight (Mw)/number average molecular weight (Mn) showing the molecular weight distribution is preferably 1.8 or more and 10 or less, further 1.8 to 7, and further 1.8 to. It is preferably 5. When the molecular weight distribution (Mw/Mn) exceeds 10, it is not preferable in terms of durability. The weight average molecular weight and the molecular weight distribution (Mw/Mn) can be obtained from the values calculated by polystyrene measurement by GPC (gel permeation chromatography).

For the production of such a (meth)acrylic polymer (A), a known production method such as solution polymerization, bulk polymerization, emulsion polymerization, various radical polymerization and the like can be appropriately selected. Further, the obtained (meth)acrylic polymer (A) may be any of a random copolymer, a block copolymer, a graft copolymer and the like.

In solution polymerization, ethyl acetate, toluene, etc. are used as a polymerization solvent. As a specific example of solution polymerization, the reaction is usually carried out under a stream of an inert gas such as nitrogen and a polymerization initiator at about 50 to 70° C. for about 5 to 30 hours.

The polymerization initiator, chain transfer agent, emulsifier and the like used for radical polymerization are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the (meth)acrylic polymer (A) can be controlled by the amount of the polymerization initiator and the chain transfer agent used and the reaction conditions, and the amount thereof can be adjusted appropriately according to these types. It

The pressure-sensitive adhesive composition of the present invention can contain an ionic compound (B). As the ionic compound (B), an alkali metal salt and/or an organic cation-anion salt can be preferably used. As the alkali metal salt, organic and inorganic salts of alkali metal can be used. The term “organic cation-anion salt” as used in the present invention means an organic salt in which the cation portion is composed of an organic substance, and the anion portion may be an organic substance or an inorganic substance. It may be. The “organic cation-anion salt” is also called an ionic liquid or an ionic solid. By containing the ionic compound (B) in the pressure-sensitive adhesive layer, it is possible to reduce the surface resistance value of the pressure-sensitive adhesive layer and suppress the generation of static electricity, and the alignment of the liquid crystal layer due to charging is disturbed and light leakage ( It is possible to suppress the occurrence of uneven charging.

<Alkali metal salt>
Examples of the alkali metal ion forming the cation portion of the alkali metal salt include lithium, sodium and potassium ions. Among these alkali metal ions, lithium ion is preferable.

The anion part of the alkali metal salt may be composed of an organic material or an inorganic material. Examples of the anion moiety constituting the organic salt include CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , C ₄ F ₉ SO ₃ ^{_{_{^{-, C 3 F 7 COO -}}}} , (CF 3 SO 2) (CF 3 CO) N -, - O 3 S (CF 2) 3 SO 3 -, PF 6 -, CO 3 2-, or the following general formula ( A) to (D),
(A): (C _n F _2n+1 SO ₂ ) ₂ N ⁻ (where n is an integer of 10 to 10),
(B): CF ₂ (C _m F _2m SO ₂ ) ₂ N ⁻ (where m is an integer of 1 to 10),
^{_{_{(C): - O 3 S}}} (CF 2) l SO 3 - ( where, l is an integer of from 1 to 10),
(D): (C _p F _2p+1 SO ₂ )N ⁻ (C _q F _2q+1 SO ₂ ), where p and q are integers from 1 to 10, and the like are used. In particular, the anion moiety containing a fluorine atom is preferably used because an ionic compound having a good ion dissociation property can be obtained. Examples of the anion moiety constituting the inorganic salt include Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , AsF ₆ ⁻ , SbF. ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN) ₂ N ⁻ , etc. are used. As the anion moiety, (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , and the like, represented by the above general formula (A), (perfluoroalkylsulfonyl)imide are preferable, and (Trifluoromethanesulfonyl)imide represented by CF ₃ SO ₂ ) ₂ N ⁻ is preferable.

Specific examples of the organic salt of an alkali metal include sodium acetate, sodium alginate, sodium ligninsulfonate, sodium toluenesulfonate, LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N and Li(CF ₃ SO ₂ _{_{_{_{) 2 N, Li (C 2}}}} F 5 SO 2) 2 N, Li (C 4 F 9 SO 2) 2 N, Li (CF 3 SO 2) 3 C, KO 3 S (CF 2) 3 SO 3 K, _{_{_{LiO 3 S (CF 2) 3}}} SO 3 K , and the like, among these _{_{_{_{LiCF 3 SO 3, Li (CF}}}} 3 SO 2) 2 N, Li (C 2 F 5 SO 2) 2 N, Li (C 4 _{_{_{F 9 SO 2) 2 N,}}} Li (CF 3 SO 2) 3 C and the like are _{_{_{_{preferable, Li (CF 3 SO 2)}}}} 2 N, Li (C 2 F 5 SO 2) 2 N, Li (C 4 F 9 SO ₂ ) A fluorine-containing lithium imide salt that is a bis(fluorosulfonyl)imide lithium salt such as ₂ N is more preferable, and a (perfluoroalkylsulfonyl)imide lithium salt is particularly preferable. Other examples include 4,4,5,5-tetrafluoro-1,3,2-dithiazolidine-1,1,3,3-tetraoxide lithium salt.

Also, examples of inorganic salts of alkali metals include lithium perchlorate and lithium iodide.

<Organic cation-anion salt>
The organic cation-anion salt used in the present invention is composed of a cation component and an anion component, and the cation component is an organic substance. As the cation component, specifically, a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, a cation having a pyrrole skeleton, an imidazolium cation, a tetrahydropyrimidinium cation, a dihydropyrimidinium cation, Examples thereof include a pyrazolium cation, a pyrazolinium cation, a tetraalkylammonium cation, a trialkylsulfonium cation, and a tetraalkylphosphonium cation.

Examples of the anion component include Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO. ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN) ₂ N ⁻ , C ₄ F _{_{^{_{_{9 SO 3 -, C 3 F}}}}} 7 COO -, ((CF 3 SO 2) (CF 3 CO) N -, - O 3 S (CF 2) 3 SO 3 -, or the following general formula (A) to (D ),
(A): (C _n F _2n+1 SO ₂ ) ₂ N ⁻ (where n is an integer of 0 to 10),
(B): CF ₂ (C _m F _2m SO ₂ ) ₂ N ⁻ (where m is an integer of 1 to 10),
^{_{_{(C): - O 3 S}}} (CF 2) l SO 3 - ( where, l is an integer of from 1 to 10),
(D): (C _p F _2p+1 SO ₂ )N ⁻ (C _q F _2q+1 SO ₂ ), where p and q are integers from 1 to 10, and the like are used. Among them, the anion component containing a fluorine atom is particularly preferably used because an ionic compound having a good ionic dissociation property can be obtained.

As the organic cation-anion salt, a compound comprising a combination of the above cation component and anion component is appropriately selected and used. Specific preferred examples of the organic cation-anion salt include, for example, methyltrioctylammonium bis(trifluoromethanesulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, ethylmethylimidazolium bis( Fluorosulfonylimide). Among them, 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide and ethylmethylimidazolium bis(fluorosulfonylimide) are more preferable.

As the ionic compound (B), in addition to the above-mentioned alkali metal salts and organic cation-anion salts, inorganic salts such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride and ammonium sulfate. Is mentioned.

The ionic compound (B) may be used alone or in combination in order to obtain a desired resistance value. In particular, when it is intended to control the surface resistance value of the pressure-sensitive adhesive layer in the range of 1×10 ¹⁰ to 1×10 ¹² Ω/□, as the ionic compound (B), an alkali metal salt is an antistatic agent. It is preferable from the viewpoint of enhancing the performance, and by using the alkali metal salt, a pressure-sensitive adhesive having high antistatic performance can be obtained even with a small number of parts. On the other hand, when it is intended to control the surface resistance value of the pressure-sensitive adhesive layer in the range of 1×10 ⁸ to 1×10 ¹⁰ Ω/□, an organic cation-anion salt is used as the ionic compound (B). It is preferable in terms of enhancing antistatic performance, and by using an organic cation-anion salt, a pressure-sensitive adhesive having high antistatic performance can be obtained even with a smaller number of parts.

The ratio of the ionic compound (B) in the pressure-sensitive adhesive composition of the present invention can be appropriately adjusted so as to satisfy the antistatic property of the pressure-sensitive adhesive layer and the sensitivity of the touch panel. For example, the amide group-containing group introduced into the (meth)acrylic polymer (A) so that the surface resistance value of the pressure-sensitive adhesive layer is in the range of 1.0×10 ⁸ to 1.0×10 ¹² Ω/□. It is preferable to adjust the ratio of the ionic compound (B) according to the type of liquid crystal panel with a built-in touch sensing function, taking into consideration the weight ratio of the monomer (a2), the type of transparent protective film of the polarizing film, and the like. For example, in the in-cell type liquid crystal panel with a touch sensing function shown in FIG. 2, the pressure-sensitive adhesive layer is preferably controlled to have an initial surface resistance value in the range of 1×10 ⁸ to 1×10 ¹⁰ Ω/□. .. In the liquid crystal panel with a touch sensing function of the semi-in-cell type shown in FIG. 3 or the on-cell type shown in FIG. 4, the adhesive layer has an initial surface resistance value of 1×10 ¹⁰ to 1×10 ¹² Ω/ It is preferable to control in the range of □.

If the amount of the ionic compound (B) increases, the ionic compound (B) may precipitate, and further, peeling due to humidification is likely to occur. The ratio of the ionic compound (B) is usually preferably 40 parts by weight or less, more preferably 30 parts by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer (A). Further, it is preferably 20 parts by weight or less, and most preferably 10 parts by weight or less. On the other hand, in order to improve the antistatic performance, it is preferable to use 0.01 part by weight or more of the ionic compound (B). From this viewpoint, the ionic compound (B) is preferably 0.1 part by weight or more, and more preferably 0.5 part by weight or more. On the other hand, when the amount of the ionic compound (B) increases, the surface resistance value becomes too low and the baseline fluctuation (malfunction at the time of touch caused by the surface resistance value being too low) may reduce the sensitivity of the touch panel. There is.

The pressure-sensitive adhesive composition of the present invention may contain a crosslinking agent (C). An organic crosslinking agent or a polyfunctional metal chelate can be used as the crosslinking agent (C). Examples of the organic crosslinking agent include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, imine crosslinking agents, and the like. The polyfunctional metal chelate is a polyvalent metal having a covalent bond or a coordinate bond with an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn and Ti. Can be mentioned. Examples of the atom in the organic compound that forms a covalent bond or a coordinate bond include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

As the crosslinking agent (C), an isocyanate crosslinking agent and/or a peroxide crosslinking agent are preferable.

As the isocyanate cross-linking agent (C), a compound having at least two isocyanate groups can be used. For example, known aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates and the like which are generally used for urethanization reaction are used.

The peroxide can be appropriately used as long as it generates a radical active species by heating or light irradiation to promote crosslinking of the base polymer of the pressure-sensitive adhesive composition, but in consideration of workability and stability. It is preferable to use a peroxide having a 1-minute half-life temperature of 80° C. to 160° C., and more preferably 90° C. to 140° C.

Examples of peroxides that can be used include di(2-ethylhexyl)peroxydicarbonate (1 minute half-life temperature: 90.6° C.), di(4-t-butylcyclohexyl)peroxydicarbonate (1 Minute half-life temperature: 92.1° C.), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: 92.4° C.), t-butyl peroxy neodecanoate (1 minute half-life temperature: 103 0.5° C.), t-hexyl peroxypivalate (1 minute half-life temperature: 109.1° C.), t-butyl peroxypivalate (1 minute half-life temperature: 110.3° C.), dilauroyl peroxide ( 1-minute half-life temperature: 116.4°C), di-n-octanoyl peroxide (1-minute half-life temperature: 117.4°C), 1,1,3,3-tetramethylbutylperoxy-2-ethyl Hexanoate (1 minute half-life temperature: 124.3°C), di(4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2°C), dibenzoyl peroxide (1 minute half-life temperature: 130. 0°C), t-butylperoxyisobutyrate (1 minute half-life temperature: 136.1°C), 1,1-di(t-hexylperoxy)cyclohexane (1 minute half-life temperature: 149.2°C) Etc. Among them, since the crosslinking reaction efficiency is particularly excellent, di(4-t-butylcyclohexyl)peroxydicarbonate (1 minute half-life temperature: 92.1° C.), dilauroyl peroxide (1 minute half-life temperature: 116. 4° C.), dibenzoyl peroxide (1 minute half-life temperature: 130.0° C.) and the like are preferably used.

The amount of the cross-linking agent (C) used is preferably 3 parts by weight or less, more preferably 0.01 to 3 parts by weight, further 0.02 parts by weight based on 100 parts by weight of the (meth)acrylic polymer (A). The amount is preferably 2 to 2 parts by weight, more preferably 0.03 to 1 part by weight. When the amount of the cross-linking agent (C) is less than 0.01 parts by weight, the pressure-sensitive adhesive layer may be insufficiently cross-linked, and durability and adhesive properties may not be satisfied, while when it is more than 3 parts by weight, the pressure-sensitive adhesive layer may be insufficient. It tends to be too hard and the durability tends to decrease.

The pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent (D). The durability can be improved by using the silane coupling agent (D). Specific examples of the silane coupling agent include, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3, Epoxy group-containing silane coupling agent such as 4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl- Amino group-containing silane coupling agents such as N-(1,3-dimethylbutylidene)propylamine, N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltri Examples thereof include (meth)acrylic group-containing silane coupling agents such as ethoxysilane, and isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane. As the silane coupling agent exemplified above, an epoxy group-containing silane coupling agent is preferable.

Also, as the silane coupling agent (D), one having a plurality of alkoxysilyl groups in the molecule can be used. Specifically, for example, X-41-1053, X-41-1059A, X-41-1056, X-41-1805, X-41-1818, X-41-1810, X-40 manufactured by Shin-Etsu Chemical Co., Ltd. -2651 and the like. A silane coupling agent having a plurality of alkoxysilyl groups in these molecules does not easily volatilize, and since it has a plurality of alkoxysilyl groups, it is effective in improving durability and is preferable. In particular, the durability is also suitable when the adherend of the optical film with the pressure-sensitive adhesive layer is a transparent conductive layer (for example, ITO) in which an alkoxysilyl group is less likely to react than glass. The silane coupling agent having a plurality of alkoxysilyl groups in the molecule preferably has an epoxy group in the molecule, and more preferably has a plurality of epoxy groups in the molecule. The silane coupling agent having a plurality of alkoxysilyl groups in the molecule and having an epoxy group tends to have good durability even when the adherend is a transparent conductive layer (for example, ITO). Specific examples of the silane coupling agent having a plurality of alkoxysilyl groups in the molecule and having an epoxy group include X-41-1053, X-41-1059A and X-41-1056 manufactured by Shin-Etsu Chemical Co., Ltd. In particular, X-41-1056 manufactured by Shin-Etsu Chemical Co., which has a high epoxy group content, is preferable.

The silane coupling agent (D) may be used alone or in combination of two or more kinds, but the content as a whole is the (meth)acrylic polymer (A)100. The amount is preferably 5 parts by weight or less, more preferably 0.001 to 5 parts by weight, further preferably 0.01 to 1 part by weight, further preferably 0.02 to 1 part by weight, and further preferably Is preferably 0.05 to 0.6 parts by weight. This is the amount that improves durability.

A polyether compound (E) having a reactive silyl group can be added to the pressure-sensitive adhesive composition of the present invention. The polyether compound (E) is preferable in that the reworkability can be improved. As the polyether compound (E), for example, those disclosed in JP 2010-275522A can be used.

The proportion of the polyether compound (E) in the pressure-sensitive adhesive composition of the present invention is preferably 10 parts by weight or less, and more preferably 0.001 to 10 parts by weight, based on 100 parts by weight of the (meth)acrylic polymer (A). .. When the amount of the polyether compound (E) is less than 0.001 part by weight, the effect of improving reworkability may not be sufficient. The polyether compound (E) is preferably 0.01 part by weight or more, and more preferably 0.1 part by weight or more. On the other hand, if the amount of the polyether compound (E) is more than 10 parts by weight, it is not preferable in terms of durability. The polyether compound (E) is preferably 5 parts by weight or less, and more preferably 2 parts by weight or less. The ratio of the polyether compound (E) can be set to a preferable range by adopting the upper limit value or the lower limit value.

Further, the pressure-sensitive adhesive composition of the present invention may contain other known additives, for example, polyether compounds of polyalkylene glycol such as polypropylene glycol, colorants, powders such as pigments, dyes, Surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metals Powders, particles, foils and the like can be appropriately added depending on the intended use. Further, a redox system to which a reducing agent is added may be adopted within a controllable range. These additives are preferably used in an amount of 5 parts by weight or less, more preferably 3 parts by weight or less, and further preferably 1 part by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A).

As a method for forming a pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive composition is applied to a release-treated separator or the like, and a polymerization solvent or the like is dried and removed to form a pressure-sensitive adhesive layer, which is then transferred to an optical film (polarizing film). Or a method of forming the pressure-sensitive adhesive layer on the optical film by coating the pressure-sensitive adhesive composition on an optical film (polarizing film) and drying and removing the polymerization solvent. When applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

The thickness of the adhesive layer is not particularly limited and is, for example, about 1 to 100 μm. The thickness is preferably 2 to 50 μm, more preferably 2 to 40 μm, and further preferably 5 to 35 μm.

<Image display panel, image display device>
The polarizing film with an adhesive layer of the present invention can be applied to various image display panels, and the image display panel can be applied to conventional image display devices. Other configurations of the image display device are the same as those of the conventional image display device. Specific examples of the image display device to which the image display panel is applicable include a liquid crystal display device, an electroluminescence (EL) display, a plasma display (PD), and a field emission display (FED). ..

The polarizing film with an adhesive layer of the present invention has a small surface resistance variation ratio, and is suitable for application to a liquid crystal panel with a built-in touch sensing function.

Further, in addition to the above configuration, the liquid crystal panel may be provided with an optical film such as a retardation film, a viewing angle compensation film, and a brightness enhancement film as appropriate.

The liquid crystal layer is not particularly limited, and may be of any type such as TN type, STN type, π type, VA type, IPS type, or any other type. The transparent substrate 9 (light source side) is not particularly limited as long as it is a transparent substrate, and examples thereof include glass and a transparent resin film base material. Examples of the transparent resin film base material include those mentioned above.

A polarizing film with a pressure-sensitive adhesive layer, which is conventionally used in this field, can be used on the light source side of the liquid crystal layer, and those described in the present specification can also be preferably used.

Specific examples of the liquid crystal panel with a built-in touch sensing function are shown in FIGS. 2 to 4, for example. 2 to 4 illustrate the case where the polarizing film with an adhesive layer 1 shown in FIG. 1 is used as the polarizing film with an adhesive layer of the present invention on the viewing side of a liquid crystal cell. That is, the piece protective polarizing film 11 and the pressure-sensitive adhesive layer 21 in FIG. 1 are shown as the first polarizing film 11 and the first pressure-sensitive adhesive layer 21 in FIGS. 2 to 4.

FIG. 2 shows a so-called in-cell type liquid crystal panel with a built-in touch sensing function, and from the viewer side, the first polarizing film 11, the first adhesive layer 21, the first transparent substrate 41, the touch sensor portion 5, the liquid crystal layer 3/ The drive electrode/sensor unit 6/second transparent substrate 42/second adhesive layer 22/second polarizing film 12 is configured. In the in-cell type liquid crystal panel with a touch sensing function of FIG. 2, for example, the liquid crystal cell C includes the touch sensor unit 5 and the drive electrode/sensor in the first and second glass substrates 41 and 42 (in the liquid crystal cell) with the liquid crystal layer 3 interposed therebetween. It has a part 6.

Further, FIG. 3 is a modification of a so-called in-cell type (semi-in-cell type) liquid crystal panel with a touch sensing function. 1 transparent substrate 41/liquid crystal layer 3/driving electrode/sensor section 6/second transparent substrate 42/second pressure-sensitive adhesive layer 22/second polarizing film 12. In the in-cell type liquid crystal panel with a touch sensing function of FIG. 3, for example, the liquid crystal cell C is outside the first transparent substrate 41, the touch sensor unit 5 is in direct contact with the first adhesive layer 21, and the liquid crystal layer 3 is sandwiched. The first and second glass substrates 41, 42 (in the liquid crystal cell) have the drive electrode/sensor unit 6 on the side of the second transparent substrate 42.

Further, FIG. 4 shows a so-called on-cell type liquid crystal panel with a built-in touch sensing function, and from the viewing side, the first polarizing film 11, the first adhesive layer 21, the touch sensor unit 5, the drive electrode/sensor unit 6 and the 1 transparent substrate 41/liquid crystal layer 3/driving electrode 7/second transparent substrate 42/second adhesive layer 22/second polarizing film 12. In the on-cell liquid crystal panel with a built-in touch sensing function of FIG. 4, for example, the liquid crystal cell C has the touch sensor unit 5 and the drive electrode/sensor unit 6 outside the first transparent substrate 41, and the touch sensor unit 5 is the first The drive electrode 7 is provided on the side of the second transparent substrate 42 in the first and second glass substrates 41 and 42 (in the liquid crystal cell) that is in direct contact with the adhesive layer 21 and that sandwiches the liquid crystal layer 3.

In the liquid crystal panel with a built-in touch sensing function, when the touch sensor unit 5 of the liquid crystal cell C and the first adhesive layer 21 are in direct contact, the first adhesive layer 21 (containing an ionic compound) is prevented from being charged. The function tends to deteriorate, especially in a humid environment. Therefore, the liquid crystal panel with a built-in touch sensing function of the present invention is preferably applied to the in-cell type (modification) shown in FIG. 3 or the on-cell type liquid crystal panel with a touch sensing function shown in FIG.

The first polarizing film 11 arranged on the viewer side of the liquid crystal cell C and the second polarizing film 12 arranged on the opposite side of the viewer side are different optical films depending on the suitability of their respective locations. It can be used by stacking. As the other optical film, for example, a liquid crystal display device such as a reflection plate, an anti-transmission plate, a retardation film (including a wavelength plate such as 1/2 or 1/4), a visual compensation film, and a brightness enhancement film is formed. Examples of the optical layer that can be used for These can be used in one layer or two or more layers. Even when these other optical films are used, it is preferable that the pressure-sensitive adhesive layer closest to the liquid crystal layer 3 is the first pressure-sensitive adhesive layer 21.

The liquid crystal layer 3 included in the liquid crystal cell C is a liquid crystal layer that is applied to a liquid crystal panel with a built-in touch sensing function and that includes liquid crystal molecules that are homogeneously aligned in the absence of an electric field. As the liquid crystal layer 3, for example, an IPS type liquid crystal layer is preferably used. In addition, as the liquid crystal layer 3, for example, any type of liquid crystal layer of TN type, STN type, π type, VA type or the like can be used. The thickness of the liquid crystal layer is, for example, about 1.5 μm to 4 μm.

In the liquid crystal cell C, the first transparent substrate 41 and the second transparent substrate 42 can form a liquid crystal cell with the liquid crystal layer 3 interposed therebetween. A touch sensor unit 5, a drive electrode/sensor unit 6, a drive electrode 7 and the like are formed inside or outside the liquid crystal cell according to the form of the liquid crystal panel with a built-in touch sensing function. Further, a color filter substrate can be provided on the liquid crystal cell (first transparent substrate 41).

The material forming the transparent substrate is, for example, glass or polymer film. Examples of the polymer film include polyethylene terephthalate, polycycloolefin, polycarbonate and the like. When the transparent substrate is made of glass, its thickness is, for example, about 0.3 mm to 1 mm. When the transparent substrate is formed of a polymer film, its thickness is, for example, about 10 μm to 200 μm. The transparent substrate may have an easy adhesion layer or a hard coat layer on its surface.

The touch sensor unit 5 (electrostatic capacitance sensor), the drive electrode/sensor unit 6, and the drive electrode 7 are formed as a transparent conductive layer. The constituent material of the transparent conductive layer is not particularly limited, and examples thereof include metals such as gold, silver, copper, platinum, palladium, aluminum, nickel, chromium, titanium, iron, cobalt, tin, magnesium, and tungsten, and these metals. Examples include alloys. In addition, examples of the constituent material of the transparent conductive layer include metal oxides of indium, tin, zinc, gallium, antimony, zirconium and cadmium, and specifically, indium oxide, tin oxide, titanium oxide, cadmium oxide and these. A metal oxide composed of a mixture of In addition, other metal compounds such as copper iodide are used. The metal oxide may further contain an oxide of a metal atom shown in the above group, if necessary. For example, indium oxide (ITO) containing tin oxide and tin oxide containing antimony are preferably used, and ITO is particularly preferably used. The ITO preferably contains 80 to 99% by weight of indium oxide and 1 to 20% by weight of tin oxide.

There is no limitation on the location where the touch sensor layer 5 is formed in the liquid crystal cell C, and the touch sensor layer 5 is formed according to the form of the liquid crystal panel with the touch sensing function. For example, FIGS. 2 to 4 illustrate the case where the touch sensor layer 5 is arranged between the first polarizing film 11 and the liquid crystal layer 3. The touch sensor layer 5 can be formed as a transparent electrode pattern on the first transparent substrate 41, for example. Also for the drive electrode/sensor unit 6 and the drive electrode 7, a transparent electrode pattern can be formed according to a conventional method according to the form of the liquid crystal panel with a touch sensing function. The transparent electrode pattern is usually electrically connected to a wiring line (not shown) formed at an end of the transparent substrate, and the wiring line is connected to a controller IC (not shown). The shape of the transparent electrode pattern may be a comb shape, a stripe shape, a rhombus shape, or any other shape depending on the application. The height of the transparent electrode pattern is, for example, 10 nm to 100 nm, and the width is 0.1 mm to 5 mm.

Also, for the liquid crystal panel with a built-in touch sensing function, a member forming a liquid crystal display device such as a backlight or a reflection plate used for an illumination system can be appropriately used.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all parts and% in each example are based on weight. Unless otherwise specified below, the room temperature standing condition is 23° C. and 65% RH.

<Measurement of weight average molecular weight of (meth)acrylic polymer (A)>
The weight average molecular weight (Mw) of the (meth)acrylic polymer (A) was measured by GPC (gel permeation chromatography). Similarly, Mw/Mn was measured. Further, it was similarly applied (other than the solvent) to the measurement of the weight average molecular weight of the polymer (a) and the like.
・Analyzer: HLC-8120GPC manufactured by Tosoh Corporation
・Column: manufactured by Tosoh Corporation, G7000H _XL + GMH _XL + GMH _XL
・Column size: Each 7.8 mmφ×30 cm, total 90 cm
・Column temperature: 40℃
・Flow rate: 0.8 mL/min
・Injection volume: 100 μL
・Eluent: Tetrahydrofuran ・Detector: Differential refractometer (RI)
・Standard sample: polystyrene

<Preparation of one-sided protective polarizing film (1)>
(Production of thin polarizer A)
Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of 75° C. was corona-treated on one side of the base material, and the corona-treated surface was treated with polyvinyl chloride. Alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. An aqueous solution containing the product name “Gosephimmer Z200”) in a ratio of 9:1 was applied and dried at 25° C. to form a PVA-based resin layer having a thickness of 11 μm to prepare a laminate.
The obtained laminate was uniaxially stretched by 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120° C. (in-air auxiliary stretching treatment).
Next, the laminated body was immersed in an insolubilizing bath having a liquid temperature of 30° C. (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Then, the polarizing plate was immersed in a dyeing bath having a liquid temperature of 30° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 part by weight of iodine was added to 100 parts by weight of water, and 1.0 part by weight of potassium iodide was added, and the resultant was immersed in an aqueous iodine solution for 60 seconds (dyeing treatment). ..
Then, it was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 30° C. (an aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water). (Crosslinking treatment).
Then, the laminate was immersed in an aqueous boric acid solution having a liquid temperature of 70° C. (an aqueous solution obtained by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with 100 parts by weight of water). On the other hand, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) such that the total stretching ratio was 5.5 (underwater stretching treatment).
After that, the laminate was immersed in a cleaning bath having a liquid temperature of 30° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
As described above, an optical film laminate including a polarizer having a thickness of 5 μm was obtained.

(Preparation of adhesive applied to transparent protective film)
45 parts by weight of acryloylmorpholine, 45 parts of 1,9-nonanediol diacrylate, 10 parts of an acrylic oligomer (ARUFONUP1190, manufactured by Toagosei Co., Ltd.) obtained by polymerizing a (meth)acrylic monomer, a photopolymerization initiator (IRGACURE 907, BASF) 3 parts) and 1.5 parts of a polymerization initiator (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.) were mixed to prepare an ultraviolet curable adhesive.

(Preparation of TAC film with a hard coat layer and a thickness of 25 μm)
A UV-curable resin monomer or oligomer containing urethane acrylate as a main component is dissolved in butyl acetate to obtain a resin solution (manufactured by DIC Corporation, trade name: Unidic 17-806, solid content concentration: 80%). 5 parts of photopolymerization initiator (manufactured by BASF Ltd., trade name: IRGACURE907) and 0.1 part of leveling agent (manufactured by DIC Corp., trade name: GRANDIC PC4100) were added per 100 parts of solid content. did. Then, cyclopentanone and propylene glycol monomethyl ether were added to the solution at a ratio of 45:55 so that the solid content concentration in the solution was 36% to prepare a hard coat layer forming material. The prepared hard coat layer forming material is applied onto TJ25UL (manufactured by Fuji Film, raw material: triacetyl cellulose polymer, thickness: 25 μm) so that the hard coat layer after curing has a thickness of 7 μm to form a coating film. did. After that, the coating film is dried at 90° C. for 1 minute, and further, the coating film is irradiated with ultraviolet rays having a cumulative light intensity of 300 mJ/cm ^{2 with} a high pressure mercury lamp to cure the coating film to form a hard coat layer and to attach HC. A 25 μm TAC (triacetyl cellulose) film was prepared.

(Preparation of one-sided protective polarizing film (1))
While applying the ultraviolet curable adhesive a to the surface of the polarizer A of the optical film laminate so that the thickness of the adhesive layer after curing becomes 1 μm, the transparent protective film (25 μm TAC film with HC: Tri After bonding the acetyl cellulose film side), ultraviolet rays were irradiated as an active energy ray to cure the adhesive. Ultraviolet irradiation is performed using a gallium-encapsulated metal halide lamp, irradiation device: Fusion UV Systems, Inc. Light HAMMER10, bulb: V bulb, peak illuminance: 1600 mW/cm ² , integrated irradiation amount 1000/mJ/cm ² (wavelength 380 to 440 nm). ) Was used and the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Then, the amorphous PET substrate was peeled off to prepare a half-protective polarizing film (1) using a thin polarizer. The optical characteristics of the obtained one-sided protective polarizing film were a single substance transmittance of 42.8% and a polarization degree of 99.99%.

<Production of both protective polarizing films (2)>
The UV-curable adhesive a is applied to the polarizer surface (polarizer surface where the transparent protective film is not provided) of the one-sided protective polarizing film (1) so that the thickness of the adhesive layer after curing is 1 μm. However, after adhering TJ25UL (manufactured by Fuji Film, raw material: triacetyl cellulose-based polymer, thickness: 25 μm), ultraviolet rays are irradiated as active energy rays to cure the adhesive and both protective polarizing films (2) Was produced.

<Transparent layer forming material>
Forming material A: 75% ethyl acetate solution of urethane prepolymer consisting of tolylene diisocyanate (TDI) and trimethylolpropane (TMP) as a solution of urethane prepolymer (a) (Tosoh Corporation, trade name "Coronate L") Was used.
On the other hand, trimethylolpropane was dissolved in cyclopentanone so that the solid content concentration was 10% to prepare a trimethylolpropane solution.
To 100 parts of a 75% ethyl acetate solution of the above urethane prepolymer (manufactured by Tosoh Corporation, trade name "Coronate L"), the above trimethylolpropane solution was added, and the solid content ratio of urethane prepolymer:trimethylolpropane was 90: 10 parts of dioctyl tin dilaurate catalyst (trade name "Enbilizer OL-1" manufactured by Tokyo Fine Chemical Co., Ltd.), and a solid content of 10% with methyl isobutyl ketone as a solvent. The forming material (coating liquid) prepared in 1. was prepared.

Forming material B: Dioctyl tin dilaurate type catalyst (manufactured by Tokyo Fine Chemical Co., Ltd., trade name) 0.1 part of "Enbilizer OL-1" was added, and a urethane prepolymer coating solution was prepared with methyl isobutyl ketone as a solvent to a solid content concentration of 10%.

Forming material C: 97.0 parts of methyl methacrylate, 3.0 parts of the monomer represented by the general formula (1) (monomer of the general formula (1e)), polymerization initiator (2,2′-) 0.2 part of azobis(isobutyronitrile) was dissolved in 200 parts of toluene. Then, a polymerization reaction was carried out for 5 hours while heating at 70° C. in a nitrogen atmosphere to obtain a polymer (a) (solid content concentration: 33% by weight). The weight average molecular weight of the obtained polymer (a) was 85,000.
15 parts of the polymer (a) and 85 parts of an epoxy resin (trade name: jER (registered trademark) YX7200B35 manufactured by Mitsubishi Chemical Co., Ltd.) are mixed to prepare an acrylic-epoxy resin forming material (coating liquid). did.

<Preparation of material for forming conductive layer>
8.6 parts of a solution containing 10 to 50% by weight of a thiophene-based polymer (trade name: Denatron P-580W, manufactured by Nagase Chemtex Co., Ltd.), a solution containing an oxazoline group-containing acrylic polymer (trade name: Epocros) 1 part of WS-700, manufactured by Nippon Shokubai Co., Ltd., and 90.4 parts of water were mixed to prepare a conductive layer forming coating solution having a solid content concentration of 0.5% by weight. The obtained coating liquid for forming a conductive layer contained 0.04% by weight of a polythiophene-based polymer and 0.25% by weight of an oxazoline group-containing acrylic polymer.

Example 1
(Preparation of acrylic polymer (A))
A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser. Further, with respect to 100 parts of the monomer mixture (solid content), 0.1 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate, and nitrogen gas was added with gentle stirring. After the introduction and nitrogen substitution, a polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55° C., and a solution of an acrylic polymer having a weight average molecular weight (Mw) of 1.6 million and Mw/Mn=3.7. Was prepared.

(Preparation of adhesive composition)
To 100 parts of the solid content of the solution of the acrylic polymer obtained above, 0.1 part of an isocyanate crosslinking agent (Takenate D160N, trimethylolpropane hexamethylene diisocyanate manufactured by Mitsui Chemicals, Inc.), benzoyl peroxide (NOF Corporation) (Manufactured by Shin-Etsu Chemical Co., Ltd.: X-41-1056) and 0.3 part of an epoxy group-containing silane coupling agent (manufactured by Niper BMT Co., Ltd.) were mixed to prepare a solution of an acrylic pressure-sensitive adhesive composition. .

(Preparation of adhesive layer)
Then, the solution of the acrylic pressure-sensitive adhesive composition was applied to one side of a polyethylene terephthalate film (separator film: manufactured by Mitsubishi Kagaku Polyester Film Co., Ltd., MRF38) treated with a silicone-based release agent to form a dried pressure-sensitive adhesive layer. It was applied to a thickness of 20 μm and dried at 155° C. for 1 minute to form an adhesive layer on the surface of the separator film.

<Preparation of the one-sided protective polarizing film (1) with a transparent layer>
After applying the transparent layer forming material A to the polarizer surface (polarizer surface on which the transparent protective film is not provided) of the one-sided protective polarizing film (1) with a bar coater, heat treatment is performed at 60° C. for 12 hours. Then, a urethane resin layer having a thickness of 3 μm was formed.

<Formation of conductive layer>
The conductive layer-forming coating liquid is applied onto the transparent layer of the transparent protective film with transparent layer (1) so that the thickness after drying is 0.06 μm, and dried at 80° C. for 2 minutes to obtain a conductive layer. Formed. The obtained conductive layer contained 8% by weight and 50% by weight of a thiophene-based polymer and an oxazoline group-containing acrylic polymer, respectively.

<Preparation of One-sided Protective Polarizing Film with Adhesive Layer (1)>
Next, the pressure-sensitive adhesive layer formed on the separator film was transferred to the conductive layer formed on the transparent protective film with protective layer (1) to prepare a protective protective film with adhesive layer (1).

Examples 2 to 9, Comparative Examples 1 to 3 and Reference Example In Example 1, as shown in Table 1, the type of polarizing film, the composition of the monomer mixture used to prepare the acrylic polymer (A), and the adhesive composition Kind (EMI-FSI or Li-TFSI) of the ionic compound (B) used for the preparation of the product or its mixing ratio, thickness of the adhesive layer, presence or absence of the conductive layer, presence or absence of the transparent layer forming material, type Alternatively, a one-side protected (or both-protected) polarizing film with an adhesive layer was produced in the same manner as in Example 1 except that the thickness was changed as shown in Table 1.
In addition, the transparent layer of Example 9, after applying the transparent layer forming material C by a bar coater on the surface of the polarizer of the one-sided protective polarizing film (the surface of the polarizer on which the transparent protective film is not provided), A transparent layer having a thickness of 0.5 μm was formed by performing heat treatment at 60° C. for 2 minutes.
In the comparative example and the reference example, the transparent layer was not formed.
In Comparative Example 1 and Comparative Examples 1 and 3, no conductive layer was formed.
In the reference example, a conductive layer was formed on the side of both protective polarizing films (2) having no hard coat layer in the same manner as in Example 1, and then the pressure-sensitive adhesive layer was transferred to the surface on which the conductive layer was formed.
The blending amount of the ionic compound (B) is a value based on 100 parts of the solid content of the acrylic polymer solution.

The following evaluation was performed on the one-sided protective (or both-sided) polarizing films with the pressure-sensitive adhesive layer obtained in the above Examples, Comparative Examples and Reference. The evaluation results are shown in Table 1.

<Surface resistance value (Ω/□): conductivity>
The surface resistance value of the conductive layer was measured on the surface of the one-side protected (or both protected) polarizing film with the conductive layer on the side of the conductive layer before forming the pressure-sensitive adhesive layer. The surface resistance value of the adhesive layer was measured on the surface of the adhesive layer formed on the separator film. In addition, after peeling the separator film from the one-sided protective (or both-protected) polarizing film with an adhesive layer, the surface resistance value of the adhesive layer surface is measured, and The surface resistance value was used. The measurement was performed using MCP-HT450 manufactured by Mitsubishi Chemical Analytech.

<Evaluation of color loss at edges>
The one-sided protective (or both-sided) polarizing films with pressure-sensitive adhesive layers obtained in Examples and Comparative Examples were cut into 50 mm×50 mm, the separator film was peeled off, and then 1.2 to 1.5 mm thick alkali glass ( A sample was prepared by bonding it to a micro slide glass manufactured by Matsunami Glass Co., Ltd.) via an adhesive layer. After the sample was kept in a high temperature and high humidity environment of 60° C. and 90% RH for 500 hours, the amount of color loss at the edges was measured by a differential interference microscope (manufactured by Olympus, product name “MX-61L”) under the following conditions. .. The amount of color loss at the edges is determined by measuring the distance of the straight line that connects the corner to the location closest to the center among the portions whose colors are lighter than the center on the diagonal lines of the four corners of the sample. μm) and the average value of the four corners was taken as the amount of edge color loss of the sample.
Device: Olympus, MX-61L
Measurement conditions Lens magnification: 5 times ISO: 200
Shutter speed: 1/100
Amount of reflected light: Scale 0
White balance: Auto Transmitted light controller: LG-PS2
Amount of transmitted light: Scale 5
Polarization direction of transmitted light: Direction of crossed Nicols with respect to the transmission axis of the polarizing film

<ESD test>
After separating the separator film from the one-sided (or both-sided) protective polarizing film with adhesive layer, attach it to the visible side of the in-cell type liquid crystal cell or the on-cell type liquid crystal cell as shown in Table 1, and liquid crystal panel with a touch sensing function. It was created. That is, the polarizing films with pressure-sensitive adhesive layers obtained in Examples 2 to 8 and Comparative Example 3 were attached to the first transparent substrate of the in-cell type liquid crystal cell shown in FIG. 2 to form the first pressure-sensitive adhesive layer and the first polarized light. A film was formed. The pressure-sensitive adhesive layer-attached polarizing films obtained in Example 1, Comparative Examples 1 and 2, and Reference Example were bonded to the sensor layer (touch sensor part) of the on-cell type liquid crystal cell shown in FIG. The layer and the first polarizing film were formed. In the liquid crystal panel, an ESD (electrostatic discharge) gun (10 kV) was fired on the surface of the polarizing film, and the time until the white spots due to electricity disappeared was measured and judged according to the following criteria. This was used as the initial evaluation.
(Evaluation criteria)
A: Within 0.5 seconds.
B: More than 0.5 seconds to less than 1 second.
C: Over 1 second to within 10 seconds.
D: exceeds 10 seconds.
Further, the obtained liquid crystal panel with a built-in touch sensing function was put into a humidified environment of 60° C./95% RH for 250 hours, further dried at 40° C. for 1 hour, and then evaluated in the same manner as above.

In Table 1,
BA is butyl acrylate,
NVP is N-vinyl-2-pyrrolidone,
HBA is 4-hydroxybutyl acrylate,
AA is acrylic acid,
EMI-FSI is ethylmethylimidazolium bis(fluorosulfonylimide),
Li-TFSI represents bis(trifluoromethanesulfonyl)imide lithium.

As shown in Table 1, the polarizing film with a pressure-sensitive adhesive layer of the present invention, even when a conductive layer is provided on the side of the polarizer of the one-sided protective polarizing film, decolorization of the end portion of the polarizer in a humidified environment. It can be seen that, even when the pressure-sensitive adhesive layer contains an ionic compound, an increase in the resistance value of the pressure-sensitive adhesive layer in a humidified environment can be suppressed.

DESCRIPTION OF SYMBOLS 1 Polarizing film with an adhesive layer 11 One-sided protective polarizing film a Polarizer b Transparent protective film c Transparent layer d Conductive layer 21

Adhesive layer

11, 12 1st, 2nd

polarizing film

21, 22 1st, 2nd adhesive layer 3 liquid crystal layers 41, 42 first and second transparent substrates 5 touch sensor section 6 drive electrode/sensor section 7 drive electrode C liquid crystal cell

Claims

A polarizing film with an adhesive layer having a polarizing film and an adhesive layer,
The polarizing film has a polarizer, a transparent protective film only on one side of the polarizer, and a conductive layer on the other side of the polarizer via a transparent layer having a thickness of 10 μm or less directly formed on the polarizer. The pressure-sensitive adhesive layer is provided via the conductive layer, and the pressure-sensitive adhesive layer-attached polarizing film is provided.
The polarizing film with an adhesive layer according to claim 1, wherein the transparent layer is a cured product of a forming material containing a urethane prepolymer which is a reaction product of an isocyanate compound and a polyhydric alcohol.
The polarizing film with an adhesive layer according to claim 2, wherein the isocyanate compound contains at least one selected from tolylene diisocyanate and diphenylmethane diisocyanate.
The polarizing film with an adhesive layer according to claim 1, wherein the transparent layer contains an epoxy resin.
The transparent layer,
(A) An acrylic monomer in an amount of more than 50 parts by weight, and the following general formula (1) in an amount of more than 0 parts by weight and less than 50 parts by weight:

(In the formula, X is a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde group, and a carboxyl group. It represents a functional group containing at least one reactive group selected, and R 1 and R 2 are each independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or a substituent. Represents an optionally substituted aryl group or a heterocyclic group optionally having a substituent, and R 1 and R 2 may be linked to each other to form a ring) A polymer obtained by polymerizing and
A resin composition comprising (b) an epoxy resin,
The pressure-sensitive adhesive according to claim 1, wherein a content ratio of the polymer (a) and the epoxy resin (b) is 95:5 to 60:40 or 40:60 to 1:99 by weight. Polarizing film with agent layer.
The functional group represented by X in the general formula (1) is
General formula (2): ZY- (wherein Z is a vinyl group, a (meth)acrylic group, a styryl group, a (meth)acrylamide group, a vinyl ether group, an epoxy group, an oxetane group, a hydroxyl group, an amino group, an aldehyde. Group and a functional group containing at least one reactive group selected from the group consisting of a carboxyl group, and Y represents an organic group). The polarizing film with the adhesive layer described.
The polarizing film with a pressure-sensitive adhesive layer according to any one of claims 1 to 6, wherein the conductive layer has a thickness of 1 µm or less.
The polarizing film with a pressure-sensitive adhesive layer according to any one of claims 1 to 7, wherein the conductive layer contains a conductive polymer.
The polarizing film with an adhesive layer according to any one of claims 1 to 8, wherein the conductive layer contains at least one selected from polythiophene, polyaniline, and carbon nanotubes.
The polarizing film with a pressure-sensitive adhesive layer according to any one of claims 1 to 9, wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A).
11. The pressure-sensitive adhesive according to any one of claims 1 to 10, wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A) and an ionic compound (B). Polarizing film with agent layer.
The pressure-sensitive adhesive layer according to claim 10 or 11, wherein the (meth)acrylic polymer (A) contains, as monomer units, an alkyl (meth)acrylate (a1) and an amide group-containing monomer (a2). Polarizing film with.
The polarizing film with an adhesive layer according to claim 12, wherein the amide group-containing monomer (a2) is an N-vinyl group-containing lactam monomer.
14. The pressure-sensitive adhesive according to claim 12, wherein the amide group-containing monomer (a2) is contained as a monomer unit in the (meth)acrylic polymer (A) in an amount of 0.1% by weight or more. Polarized film with layers.
15. The ionic compound (B) is an alkali metal salt, and the surface resistance value of the pressure-sensitive adhesive layer is 1×10 10 to 1×10 12 Ω/□, which is any one of claims 11 to 14. A polarizing film with a pressure-sensitive adhesive layer as described in 1.
The ionic compound (B) is an organic cation-anion salt, and the surface resistance value of the pressure-sensitive adhesive layer is 1×10 8 to 1×10 10 Ω/□. A polarizing film with an adhesive layer according to any one of 1.
The ionic compound (B) is contained in an amount of 0.01 parts by weight or more based on 100 parts by weight of the (meth)acrylic polymer (A), according to any one of claims 11 to 16. Polarizing film with adhesive layer.
The polarizing film with an adhesive layer according to any one of claims 1 to 17, wherein the transparent protective film is a cellulose resin film or a (meth)acrylic resin film.
An image display panel comprising the polarizing film with an adhesive layer according to any one of claims 1 to 18.
20. The image display panel according to claim 19, wherein an adhesive layer of the polarizing film with an adhesive layer is attached to a liquid crystal cell with a touch sensing function having a liquid crystal layer and a touch sensor section.
An image display device comprising the image display panel according to claim 19.