KR20080093361A - Polariging plate, optical film, and image display - Google Patents

Abstract

A polarizing plate, an optical film, and an image display are provided to improve durability and productivity without a heating process by using an electron beam curing adhesive. A polarizing plate includes a polarizer, an adhesive layer, and a transparent protective film. The transparent protective film is formed on at least one surface of the polarizer while interposing the adhesive layer therebetween. The adhesive layer is made of an active energy ray curing adhesive containing at least one curing component. A glass transition temperature of the adhesive layer is more than 60°C. A thickness of the adhesive layer is 0.01 to 7mum. A gel fraction of the adhesive layer is more than 50wt%.

Description

POLARIGING PLATE, OPTICAL FILM, AND IMAGE DISPLAY}

The present invention relates to a polarizing plate. This polarizing plate can form image display apparatuses, such as a liquid crystal display device (LCD), an organic electroluminescence display, a CRT, a PDP, independently or as an optical film which laminated | stacked this.

Liquid crystal displays are rapidly expanding in markets such as watches, mobile phones, PDAs, notebook computers, PC monitors, DVD players, and TVs. A liquid crystal display device visualizes the polarization state by switching of a liquid crystal, and a polarizer is used from the display principle. In particular, high brightness, high contrast, and wide viewing angles are required for applications such as TVs, and high transmittance, high polarization, and high color reproducibility are also required in polarizing plates.

As a polarizer, the iodine type polarizer of the structure which makes iodine adsorb | suck to polyvinyl alcohol, and has elongate structure has high transmittance | permeability and high polarization degree, and is used widely as a most common polarizer. In general, a polarizing plate is used by attaching a transparent protective film on both surfaces of a polarizer with a so-called water-based adhesive obtained by dissolving a polyvinyl alcohol-based material in water (Patent Documents 1 and 2). As the transparent protective film, triacetyl cellulose having high moisture permeability and the like are used.

However, when manufacturing a polarizing plate as mentioned above, when using an aqueous adhesive like a polyvinyl alcohol-type adhesive agent, after a polarizer and a transparent protective film are affixed, a drying process is needed. The presence of a drying process in the manufacturing process of the polarizing plate is not desirable to improve the productivity of the polarizing plate.

In addition, in the case of using an aqueous adhesive (so-called wet lamination), in order to improve the adhesiveness with the adhesive, if the moisture content of the polarizer is not relatively increased (usually about 30% of the polarizer), the adhesive by the aqueous adhesive It is not possible to obtain a polarizing plate having good properties. However, the polarizing plate obtained in this way has a problem, such as a case where the dimensional change is large at high temperature and high temperature and high humidity. On the other hand, in order to suppress the said dimension change, you may use the transparent protective film which lowers the moisture content of a polarizer or low moisture permeability. However, when such a polarizer and a transparent protective film are attached by using an aqueous adhesive, the efficiency in the drying process, the polarization characteristics are inferior, or an appearance problem occurs, so that a practically useful polarizing plate cannot be obtained.

In addition, as represented by TV in particular, as the large screen of an image display apparatus advances in recent years, the enlargement of a polarizing plate becomes also very important in productivity and cost (production rate, acquisition number increase). However, in the polarizing plate using the above-mentioned water-based adhesive, the problem is that the polarizing plate causes a dimensional change due to the heat of the backlight, and it becomes uneven, so that the so-called light omission (nonuniformity) becomes remarkable in some parts of the entire screen. There is.

For the same reason as above, it has been proposed to use an active energy ray-curable (particularly ultraviolet-curable) adhesive instead of an aqueous adhesive. For example, an ultraviolet curable adhesive having an acrylic or methacrylic monomer as a diluent has been proposed for an acrylic oligomer such as epoxy acrylate, urethane acrylate or polyester acrylate as an adhesive (Patent Document 3).

In addition, the durability required for the polarizing plate is becoming strict, and durability in a harsh environment under high humidity and high temperature is demanded. However, the polarizing plate did not satisfy the durability under the harsh environment.

Patent Document 1: Japanese Unexamined Patent Publication No. 2006-220732

Patent Document 2: Japanese Patent Application Laid-Open No. 2001-296427

Patent Document 3: Japanese Patent Application Laid-Open No. 61-246719

An object of this invention is to provide the polarizing plate which can satisfy the durability in the severe environment under high humidity and high temperature.

Moreover, an object of this invention is to provide the optical film which laminated | stacked the said polarizing plate, and to provide image display apparatuses, such as a liquid crystal display device using this polarizing plate and an optical film.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the present inventors discovered what can be achieved with the said objective by the polarizing plate shown below, and came to complete this invention.

That is, this invention is a polarizing plate in which the transparent protective film is formed in at least one surface of a polarizer through an adhesive bond layer,

The adhesive layer is formed of an active energy ray curable adhesive containing at least one curable component,

Tg of an adhesive bond layer is 60 degreeC or more, and,

The thickness of an adhesive bond layer is 0.01-7 micrometers, It is related with the polarizing plate.

In the said polarizing plate, when Tg (degreeC) of an adhesive bond layer is defined as A and the thickness (micrometer) of an adhesive bond layer is B, it is preferable to satisfy Formula (1): A-12xB> 58.

In the polarizing plate, the adhesive layer preferably has a gel fraction of 50% by weight or more.

In the said polarizing plate, it is preferable that a curable component is a compound which has a (meth) acryloyl group.

In the polarizing plate, as the curing component, the general formula _{(1): CH 2 = C} (R 1) -CONR 2 (R 3) (R 1 represents a hydrogen atom or a methyl group, R ² is a hydrogen atom or a hydroxyl group, MER The C1-C4 linear or branched alkyl group which may have a capto group, an amino group, or a quaternary ammonium group, R <^3> represents a hydrogen atom or a C1-C4 linear or branched alkyl group. Except that R ² and R ³ are hydrogen atoms at the same time, or R ² and R ³ are bonded to each other to form a 5- or 6-membered ring which may contain an oxygen atom. It is preferable to use a substituted amide monomer.

As said N-substituted amide type monomer, at least 1 sort (s) chosen from N-hydroxyethyl acrylamide, N-methylol acrylamide, N-isopropyl acrylamide, and N-acryloyl morpholine is preferable. In particular, the N-substituted amide monomers preferably contain N-hydroxyethylacrylamide and N-acryloyl morpholine. When N-hydroxyethyl acrylamide and N-acryloyl morpholine are used together, it is preferable to use so that the ratio of N-hydroxyethyl acrylamide may be 40 weight% or more with respect to these total amounts.

Moreover, the monofunctional (meth) acrylate which has an aromatic ring and a hydroxyl group can be used together as N-substituted amide monomer further as a curable component.

In the polarizing plate, the active energy ray-curable adhesive is preferably an electron beam-curable adhesive.

In the polarizing plate, at least one selected from a cellulose resin, a polycarbonate resin, a cyclic polyolefin resin, and a (meth) acrylic resin is preferably used as the transparent protective film.

Moreover, this invention relates to the optical film characterized by the above-mentioned at least 1 piece of said polarizing plate being laminated | stacked.

Moreover, this invention relates to the image display apparatus characterized by the said polarizing plate or the said optical film being used.

In the polarizing plate of this invention, an active energy ray hardening-type adhesive agent is used as an adhesive agent used for attachment of a polarizer and a transparent protective film. Active energy ray-curable adhesives are more durable than water-based adhesives. In addition, in the polarizing plate of the present invention, the Tg of the adhesive layer formed by the active energy ray-curable adhesive is 60 ° C or more, and the thickness of the adhesive layer is controlled to be 0.01 to 7 µm. Thus, in the polarizing plate of this invention, an adhesive layer becomes high Tg of 60 degreeC or more, and while using an active-energy-ray-curable adhesive agent, and controlling the thickness of an adhesive bond layer in the said range, durability in severe environment under high humidity and high temperature. Is satisfying. In particular, in the case where Tg (° C.) of the adhesive layer is defined as A and the thickness (μm) of the adhesive layer is defined as B, the above durability is preferable when the expression (1): A-12 × B> 58 is satisfied. .

As an active energy ray hardening-type adhesive agent used for the said polarizing plate, an electron beam hardening-type adhesive agent is preferable. The electron beam curable adhesive is more productive than the ultraviolet curable adhesive, and a heating process such as ultraviolet curing is unnecessary by using an electron beam (ie, dry lamination) in the curing method of the adhesive used to attach the polarizer and the transparent protective film. The productivity can be very high. Moreover, compared with an ultraviolet curable adhesive, durability of a polarizing plate can be improved more by using an electron beam curable adhesive.

Moreover, when using the compound which has a (meth) acryloyl group, especially the said N-substituted amide monomer as a curable component of an active energy ray hardening-type adhesive agent, this curable component is preferable at the point of durability, Especially, It is suitable as an electron beam curable adhesive. For example, even when a low moisture content polarizer is used, and also when a material with low moisture permeability is used as the transparent protective film, the electron beam curable adhesive shows good adhesion to them, and as a result, a polarizing plate having good dimensional stability is obtained. You can get it.

When using the said curable component, since a polarizing plate with a small dimensional change can be manufactured, it can respond easily also to enlargement of a polarizing plate, and can suppress a production cost from a viewpoint of a production rate and the acquisition number. Moreover, since the polarizing plate obtained by this invention has favorable dimensional stability, it can suppress generation | occurrence | production of the nonuniformity of the image display apparatus by the external heat of a backlight.

In the polarizing plate of this invention, the transparent protective film is formed in at least one surface of a polarizer through an adhesive bond layer, and an active energy ray hardening-type adhesive agent is used for formation of the said adhesive bond layer. An active energy ray hardening-type adhesive agent contains at least 1 type of curable component.

The curable component used for an active energy ray hardening-type adhesive agent is selected so that Tg of the adhesive bond layer formed by this may be 60 degreeC or more. It is preferable that Tg of the said adhesive bond layer is 70 degreeC or more from a viewpoint of durability, and it is more preferable that it is 75 degreeC or more, more 100 degreeC or more, and still more 120 degreeC or more. On the other hand, when Tg of an adhesive bond layer becomes high too much, since the flexibility of a polarizing plate will fall, it is preferable to make Tg of an adhesive bond layer 300 degrees C or less, 240 degrees C or less, and 180 degrees C or less.

As a curable component, the compound which has a (meth) acryloyl group, and the compound which has a vinyl group is mentioned. These curable components can use both monofunctional or bifunctional or more. These curable components can be used 1 type or can be used in combination of 2 or more types so that the adhesive bond layer formed by a curable component may satisfy Tg60 degreeC or more. As these curable components, the compound which has a (meth) acryloyl group is preferable. As the compound having a (meth) acryloyl group, an N-substituted amide monomer is preferably used. These monomers are preferable at the point of adhesiveness. In addition, a (meth) acryloyl group means acryloyl group and / or methacryloyl group. In the present invention, (meth) has the same meaning as described above.

N-substituted amide monomers are represented by the general formula (1): CH ₂ = C (R ¹ ) -CONR ² (R ³ ) (R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a hydroxyl group, mercap An alkyl group having 1 to 4 carbon atoms or a branched chain which may have an earth, amino or quaternary ammonium group, and R ³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or a branched chain; The case where R <^2> , R <^3> is a hydrogen atom at the same time is excluded, or R <^2> , R <^3> combines and forms the 5-membered ring or 6-membered ring which may contain an oxygen atom. As a C1-C4 linear or branched alkyl group in R <^2> or R <^3> in the said General formula (1), a methyl group, an ethyl group, isopropyl group, t-butyl group etc. are mentioned, for example. Examples of the alkyl group having a hydroxyl group include a hydroxymethyl group and a hydroxyethyl group. Examples of the alkyl group having an amino group include an aminomethyl group and an aminoethyl group. Moreover, when R <^2> , R <^3> combines and forms the 5-membered ring or 6-membered ring which may contain an oxygen atom, it has a heterocyclic ring which has nitrogen. As said heterocyclic ring, a morpholine ring, a piperidine ring, a pyrrolidine ring, a piperazine ring, etc. are mentioned.

Specific examples of the N-substituted amide monomers include, for example, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-iso Propylacrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylol-N- Propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaptomethyl (meth) acrylamide, mercaptoethyl (meth) acrylamide and the like. Moreover, as a heterocyclic containing monomer which has a heterocyclic ring, N-acryloyl morpholine, N-acryloyl piperidine, N-methacryloyl piperidine, N-acryloyl pyrrolidine, etc. are mentioned, for example. Can be mentioned. These N-substituted amide monomers can be used individually by 1 type or in combination of 2 or more type.

As said N-substituted amide type monomer, N-hydroxyethyl acrylamide, N-methylol acrylamide, N-isopropyl acrylamide, and N-acryloyl morpholine are preferable. Although the N-substituted amide monomer shows good adhesion to a low moisture content polarizer and a transparent protective film using a material with low moisture permeability, the monomers exemplified above exhibit particularly good adhesion. Especially, N-hydroxyethyl acrylamide is preferable.

Although the said N-substituted amide type monomer can be used individually or in combination of 2 or more types, when combining 2 or more types, N-hydroxyethyl acrylamide and N-acryloyl mor from a viewpoint of durability and adhesiveness. Combinations of Pauline are preferred. In the combination, the ratio of N-hydroxyethylacrylamide to the total amount of N-hydroxyethylacrylamide and N-acryloyl morpholine is preferably 40% by weight or more in order to obtain good adhesiveness. As for the said ratio, 40-90 weight% is more preferable, Furthermore, it is preferable that it is 60-90 weight%.

Moreover, as said curable component, besides the above, as a compound which has a (meth) acryloyl group, for example, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and various (Meth) acrylate type monomer etc. are mentioned. Among these, epoxy (meth) acrylate, especially monofunctional (meth) acrylate which has an aromatic ring and a hydroxyl group, is used preferably. These curable components are used alone and in combination with the N-substituted amide monomer when the adhesive layer of Tg 60 ° C or higher cannot be formed.

As the monofunctional (meth) acrylate having an aromatic ring and a hydroxyl group, various monofunctional (meth) acrylates having an aromatic ring and a hydroxyl group can be used. Although the hydroxyl group may exist as a substituent of an aromatic ring, it is preferable in this invention to exist as an organic group (hydrocarbon group, especially what couple | bonded with the alkylene group) which couple | bonds an aromatic ring and a (meth) acrylate.

As monofunctional (meth) acrylate which has the said aromatic ring and a hydroxyl group, the reaction material of the monofunctional epoxy compound which has an aromatic ring, and (meth) acrylic acid is mentioned, for example. As a monofunctional epoxy compound which has an aromatic ring, phenyl glycidyl ether, t-butylphenyl glycidyl ether, phenyl polyethyleneglycol glycidyl ether, etc. are mentioned, for example. As a specific example of the monofunctional (meth) acrylate which has an aromatic ring and a hydroxyl group, For example, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-t-butylphenoxypropyl ( Meth) acrylate, 2-hydroxy-3-phenylpolyethylene glycol propyl (meth) acrylate, and the like.

Moreover, a carboxyl group monomer is mentioned as a compound which has a (meth) acryloyl group. A carboxyl monomer is also preferable at an adhesive point. As a carboxyl monomer, (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, etc. are mentioned, for example. Among these, acrylic acid is preferable.

In addition to the above, examples of the compound having a (meth) acryloyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl C1-C12 alkyl (meth) acrylates, such as (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate; (Meth) acrylate alkoxyalkyl monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, Hydroxy group-containing monomers such as (meth) acrylic acid 10-hydroxydecyl, (meth) acrylic acid 12-hydroxylauryl and (4-hydroxymethylcyclohexyl) -methylacrylate; Acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; Caprolactone adducts of acrylic acid; Contains sulfonic acid groups, such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamide propanesulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloyloxy naphthalene sulfonic acid Monomers; Phosphoric acid group containing monomers, such as 2-hydroxyethyl acryloyl phosphate, etc. are mentioned. Moreover, (meth) acrylamide; Maleimide, N-cyclohexyl maleimide, N-phenylmaleimide, etc .; Aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, 3- (3-pyridylyl) propyl (meth) acrylate (Meth) acrylic-acid alkylaminoalkyl monomers, such as these; Such as N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, and N- (meth) acryloyl-8-oxyoctamethylene succinimide Nitrogen containing monomers, such as a succinimide type monomer, are mentioned.

As described above, as the curable component in the active energy ray-curable adhesive, an N-substituted amide monomer alone or a monofunctional (meth) acrylate having an N-substituted amide monomer and an aromatic ring and a hydroxyl group It is preferable to use together. When using them together, it is preferable to make the ratio of N-substituted amide type monomer into 40 weight% or more, more 50 weight% or more, further 60 weight% or more, even more 70 weight% or more, and also 80 weight% or more. .

As the curable component, a bifunctional or higher curable component can be used. As a bifunctional or more than curable component, bifunctional or more than (meth) acrylate, especially bifunctional or more than epoxy (meth) acrylate are preferable. An epoxy (meth) acrylate more than bifunctional can be obtained by reaction of a polyfunctional epoxy compound and (meth) acrylic acid. The polyfunctional epoxy compound can illustrate various things. As a polyfunctional epoxy compound, an aromatic epoxy resin, an alicyclic epoxy resin, and an aliphatic epoxy resin are mentioned, for example.

As an aromatic epoxy resin, For example, Bisphenol-type epoxy resins, such as the diglycidyl ether of bisphenol A, the diglycidyl ether of bisphenol F, and the diglycidyl ether of bisphenol S; Novolak-type epoxy resins, such as a phenol novolak epoxy resin, a cresol novolak epoxy resin, and a hydroxy benzaldehyde phenol novolak epoxy resin; Polyfunctional epoxy resins, such as glycidyl ether of tetrahydroxy phenylmethane, glycidyl ether of tetrahydroxy benzophenone, and epoxidized polyvinyl phenol, etc. are mentioned.

As an alicyclic epoxy resin, epoxy resins, such as a hydrogenated substance of the said aromatic epoxy resin, a cyclohexane system, a cyclohexyl methyl ester system, a cyclohexyl methyl ether system, a spiro system, and a tricyclodecane system, are mentioned.

As an aliphatic epoxy resin, the polyglycidyl ether of an aliphatic polyhydric alcohol or its alkylene oxide adduct is mentioned. Examples of these include diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, and diglycidine of polyethylene glycol. Polyether polyols obtained by adding one or two or more alkylene oxides (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as dil ether, diglycidyl ether of propylene glycol, ethylene glycol, propylene glycol and glycerin And polyglycidyl ether.

The epoxy equivalent of the said epoxy resin is 30-3000 g / equivalent normally, Preferably it is the range of 50-1500 g / equivalent.

Epoxy (meth) acrylate of an aliphatic epoxy resin is preferable, and the epoxy (meth) acrylate of a bifunctional aliphatic epoxy resin is especially preferable for the said bifunctional or more epoxy (meth) acrylate.

Although the active energy ray hardening-type adhesive agent of this invention contains a curable component, you may add an additive suitably as needed in addition to the said component. An active energy ray hardening-type adhesive agent can be used in the aspect of an electron beam curing type and an ultraviolet curing type. When using the said adhesive agent in an electron beam curing type, it is not necessary in particular to contain a photoinitiator in the said adhesive agent, but when using in an ultraviolet curing type, a photoinitiator is used. The usage-amount of a photoinitiator is about 0.1-10 weight part normally per 100 weight part of curable components, Preferably it is 0.5-3 weight part.

Moreover, as an example of an additive, the sensitizer which improves the hardening rate and the sensitivity by the electron beam represented by a carbonyl compound, etc., the adhesion promoter represented by a silane coupling agent and ethylene oxide, the additive which improves the wettability with a transparent protective film, acryloxy Representatives of compounds, hydrocarbons (natural, synthetic resins), etc., additives for improving mechanical strength and processability, ultraviolet absorbers, antioxidants, dyes, processing aids, ion traps, antioxidants, tackifiers, fillers (metal compounds) Other than fillers), plasticizers, leveling agents, foaming inhibitors, antistatic agents and the like.

The polarizer is formed of polyvinyl alcohol-based resin. The polarizer is one obtained by dyeing a polyvinyl alcohol resin film with a dichroic substance (typically iodine or a dichroic dye) and uniaxially stretching the polyvinyl alcohol resin film. The degree of polymerization of the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film is preferably 100 to 5000, more preferably 1400 to 4000. If the degree of polymerization is too low, stretching is likely to be interrupted at the time of carrying out a predetermined stretching, and if the degree of polymerization is too high, tension may be abnormally required during stretching and mechanical stretching may not be possible.

The polyvinyl alcohol-based resin film constituting the polarizer can be molded by any suitable method (e.g., casting method, casting method, extrusion method of casting a solution in which resin is dissolved in water or an organic solvent). Although the thickness of a polarizer is suitably set according to the objective and use of the LCD in which a polarizing plate is used, it is about 5-80 micrometers normally.

As a manufacturing method of a polarizer, arbitrary appropriate methods are employ | adopted according to the objective, material used, conditions, etc .. For example, the method of providing the said polyvinyl alcohol-type resin film to a series of manufacturing processes normally including a swelling, dyeing, crosslinking, extending | stretching, washing | cleaning, and a drying process is employ | adopted. In each processing process except a drying process, a process is performed by immersing a polyvinyl alcohol-type resin film in the liquid containing the solution used for each process. The order, recovery and execution of each treatment of swelling, dyeing, crosslinking, stretching, washing with water and drying can be appropriately set depending on the purpose, materials used and conditions. For example, several treatments may be performed simultaneously in one process, and swelling treatment, dyeing treatment and crosslinking treatment may be performed simultaneously. For example, it can be preferably employed to carry out the crosslinking treatment before and after the stretching treatment. For example, the water washing treatment may be performed after all treatments or may be performed only after a specific treatment.

The swelling step is typically performed by immersing the polyvinyl alcohol-based resin film in a treatment bath filled with water. By this treatment, the surface of the polyvinyl alcohol-based resin film is cleaned and the blocking agent is prevented, and the polyvinyl alcohol-based resin film is swollen to prevent unevenness such as dyeing unevenness. Glycerine, potassium iodide, etc. are added suitably to a swelling bath. The temperature of the swelling bath is usually about 20 to 60 ° C, and the immersion time in the swelling bath is usually about 0.1 to 10 minutes.

The dyeing step is typically performed by immersing the polyvinyl alcohol-based resin film in a treatment bath containing a dichroic substance such as iodine. As a solvent used for the solution of the dyeing bath, water is generally used, but an appropriate amount of an organic solvent having compatibility with water may be added. A dichroic substance is normally used in the ratio of 0.1-1 weight part with respect to 100 weight part of solvents. When using iodine as a dichroic substance, it is preferable that the solution of a dye bath further contains adjuvant, such as iodide. This is because the dyeing efficiency is improved. The adjuvant is preferably used in an amount of 0.02 to 20 parts by weight, and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the solvent. Specific examples of iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide, and the like. The temperature of a dyeing bath is about 20-70 degreeC normally, and the immersion time in a dyeing bath is about 1 to 20 minutes normally.

A crosslinking process is typically performed by immersing the said dyed polyvinyl alcohol-type resin film in the process bath containing a crosslinking agent. Arbitrary appropriate crosslinking agents are employ | adopted as a crosslinking agent. As a specific example of a crosslinking agent, boron compounds, such as a boric acid and a borax, glyoxal, a glytalaldehyde, etc. are mentioned. These are used alone or in combination. As the solvent used for the solution of the crosslinking bath, water is generally used, but an appropriate amount of an organic solvent having compatibility with water may be added. A crosslinking agent is normally used in 1-10 weight part with respect to 100 weight part of solvents. When the concentration of the crosslinking agent is less than 1 part by weight, sufficient optical properties cannot be obtained. When the density | concentration of a crosslinking agent exceeds 10 weight part, the stress which arises in a film at the time of extending | stretching may become large, and the polarizing plate obtained may shrink | contract. It is preferable that the solution of a crosslinking bath further contains adjuvant, such as iodide. This is because uniform properties can be easily obtained in plane. The concentration of the adjuvant is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight. Specific examples of iodide are the same as in the dyeing process. The temperature of the crosslinking bath is usually about 20 to 70 ° C, preferably 40 to 60 ° C. Immersion time in a crosslinking bath is about 1 second-about 15 minutes normally, Preferably it is for 5 seconds-10 minutes.

The stretching step may be performed at any stage as described above. Specifically, it may be carried out after the dyeing treatment, may be carried out before the dyeing treatment, may be carried out simultaneously with the swelling treatment, the dyeing treatment and the crosslinking treatment, or may be carried out after the crosslinking treatment. The cumulative stretching ratio of the polyvinyl alcohol-based resin film is usually 5 times or more. Preferably it is 5-7 times, More preferably, it is 5-6.5 times. When cumulative draw ratio is less than 5 times, it becomes difficult to obtain a polarizing plate of high polarization degree. When the cumulative stretching ratio exceeds 7 times, the polyvinyl alcohol-based resin film may be easily broken. Arbitrary appropriate methods are employ | adopted as a specific method of extending | stretching. For example, when the wet stretching method is adopted, the polyvinyl alcohol-based resin film is stretched at a predetermined magnification in the treatment bath. As a solution of an extending | stretching bath, the solution which added the compound of various metal salt, iodine, boron, or zinc in solvent, such as water or an organic solvent (for example, ethanol), is used preferably.

The water washing step is typically performed by immersing the polyvinyl alcohol-based resin film subjected to the above various treatments in a treatment bath. Unnecessary residue of a polyvinyl alcohol-type resin film can be wash | cleaned by the water washing process. The water washing bath may be pure water or an aqueous solution of iodide (for example, potassium iodide, sodium iodide, etc.) may be used. The concentration of the iodide aqueous solution is preferably 0.1 to 10% by weight. You may add adjuvant, such as zinc sulfate and zinc chloride, to an iodide aqueous solution. The temperature of the water washing bath is preferably 10 to 60 ° C, more preferably 30 to 40 ° C. Immersion time is for 1 second-1 minute. The water washing step may be performed only once or may be performed multiple times as necessary. In the case of carrying out a plurality of times, the kind and concentration of the additive contained in the water washing bath used for each treatment are appropriately adjusted. For example, the washing step is a step of immersing the polyvinyl alcohol-based resin film subjected to the above various treatments in an aqueous solution of potassium iodide (0.1 to 10% by weight, 10 to 60 ° C) for 1 second to 1 minute, and washing with pure water. Process. Moreover, in the washing process, in order to improve the surface modification of a polarizer and the drying efficiency of a polarizer, you may add the organic solvent (for example, ethanol etc.) which is compatible with water suitably.

Drying processes, any suitable method (eg, natural drying, blowing drying, heating drying) can be employed. For example, the drying temperature in the case of heat drying is about 20-80 degreeC normally, and a drying time is about 1 to 10 minutes normally. A polarizer can be obtained as mentioned above.

The polarizer used in the present invention preferably has a water content of 20% by weight or less, more preferably 0 to 15% by weight, still more preferably 1 to 15% by weight. When moisture content is larger than 20 weight%, there exists a possibility that the problem that the dimensional change of the obtained polarizing plate may become large and the dimensional change in high temperature or under high temperature, high humidity becomes large may arise.

What is necessary is just to adjust the moisture content of the polarizer of this invention by arbitrary appropriate methods. For example, the method of controlling by adjusting the conditions of the drying process in the manufacturing process of a polarizer is mentioned.

The moisture content of a polarizer is measured by the following method. That is, the polarizer was cut out to the size of 100x100 mm, and the initial weight of this sample was measured. Subsequently, this sample was dried at 120 degreeC for 2 hours, dry weight was measured, and moisture content was measured by the following formula. Moisture content (% by weight) = {(initial weight-dry weight) / initial weight} × 100. The weight was measured three times each and the average value was used.

As a material which comprises a transparent protective film, the thermoplastic resin which is excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, etc. is used, for example. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyether sulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, and rings. Polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. In addition, a transparent protective film is affixed on one side of the polarizer by an adhesive layer, but on the other side, a thermosetting resin such as (meth) acrylic, urethane, acrylurethane, epoxy, silicone, or ultraviolet curable resin can be used as the transparent protective film. . One or more types of arbitrary appropriate additives may be contained in the transparent protective film. As an additive, a ultraviolet absorber, antioxidant, a lubricating agent, a plasticizer, a mold release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent, etc. are mentioned, for example. Content of the said thermoplastic resin in a transparent protective film becomes like this. Preferably it is 50-100 weight%, More preferably, it is 50-99 weight%, More preferably, it is 60-98 weight%, Especially preferably, it is 70-97 weight%. When content of the said thermoplastic resin in a transparent protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has may not be fully expressed.

Moreover, as a transparent protective film, the polymer film of Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007), for example, (A) thermoplastic resin which has a substituted and / or unsubstituted imide group in a side chain, (B The resin composition containing the thermoplastic resin which has a substituted and / or unsubstituted phenyl and a nitrile group in a side chain) is mentioned. As a specific example, the resin composition film containing the alternating copolymer which consists of isobutylene and N-methyl maleimide, and an acrylonitrile styrene copolymer is mentioned. As a film, the film which consists of mixed extrusion products of a resin composition, etc. can be used. Since these films have a small retardation and a small photoelastic coefficient, problems such as unevenness due to deformation of the polarizing plate can be solved, and the moisture permeability is small, so the humidification durability is excellent.

Although the thickness of a transparent protective film can be suitably determined, it is about 1-500 micrometers generally in terms of workability, thinness, etc., such as strength and handleability. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable. A transparent protective film is especially preferable when it is 5-150 micrometers.

In addition, when forming a transparent protective film on both sides of a polarizer, the protective film which consists of the same polymer material may be used in the front and back, and the protective film which consists of different polymer materials etc. may be used.

As the transparent protective film of the present invention, it is preferable to use at least one selected from a cellulose resin, a polycarbonate resin, a cyclic polyolefin resin, and a (meth) acrylic resin. The adhesive agent for electron beam curable polarizing plates of this invention shows preferable adhesiveness with respect to the said various transparent protective films. In particular, the adhesive agent for electron beam hardening type polarizing plates of this invention shows favorable adhesiveness also to the acrylic resin which was difficult to satisfy adhesiveness.

Cellulose resins are esters of cellulose and fatty acids. Thus, as a specific example of cellulose ester-type resin, a cellulose triacetate, a cellulose diacetate, a cellulose tripropionate, a cellulose dipropionate, etc. are mentioned. Among these, cellulose triacetate is particularly preferable. Cellulose triacetate is commercially available in many products, and is advantageous in terms of availability and cost. Examples of commercially available products of cellulose triacetate include the trade name "UV-50", "UV-80", "SH-80", "TD-80U", "TD-TAC" and "UZ-TAC" manufactured by Fuji Photo Film Co., Ltd. And "KC series" manufactured by Konica Corporation. Generally, these cellulose triacetates have in-plane retardation (Re) of almost zero, but the thickness direction retardation (Rth) has a thickness of about -60 nm.

Moreover, the cellulose resin film with a small thickness direction retardation can be obtained by processing the said cellulose resin, for example. For example, a base film, such as polyethylene terephthalate, polypropylene, or stainless steel, coated with a solvent such as cyclopentanone or methyl ethyl ketone, is attached to a common cellulose-based film and dried by heating (for example, 3 to 10 at 80 to 150 ° C). After a minute), and the method of peeling a base film; A solution obtained by dissolving norbornene-based resin and (meth) acrylic resin in a solvent such as cyclopentanone or methyl ethyl ketone is coated on a common cellulose resin film and dried by heating (for example, at about 80 to 150 ° C. for about 3 to 10 minutes). After making it, the method of peeling a coating film, etc. are mentioned.

Moreover, as a cellulose resin film with a small thickness direction retardation, the fatty acid cellulose resin film which controlled fat substitution degree can be used. In the triacetyl cellulose generally used, although acetic acid substitution degree is about 2.8, Preferably, Rth can be made small by controlling acetic acid substitution degree to 1.8-2.7. Rth can be controlled small by adding plasticizers, such as dibutyl phthalate, p-toluenesulfonanilide, and acetyl triethyl citrate, to the said fatty acid substituted cellulose resin. The amount of the plasticizer added is preferably 40 parts by weight or less, more preferably 1 to 20 parts by weight, still more preferably 1 to 15 parts by weight with respect to 100 parts by weight of fatty acid cellulose resin.

Specifically as cyclic polyolefin resin, Preferably it is norbornene-type resin. Cyclic olefin resin is a generic name of resin which polymerizes cyclic olefin as a polymerization unit, For example, Unexamined-Japanese-Patent No. 1-240517, Unexamined-Japanese-Patent No. 3-14882, and Unexamined-Japanese-Patent No. 3 The resin described in -122137 etc. is mentioned. Specific examples include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, α-olefins such as cyclic olefins, ethylene and propylene, copolymers thereof (typically random copolymers), and unsaturated carboxyl Graft polymers modified with an acid or its derivatives, and those hydrides. Specific examples of the cyclic olefins include norbornene monomers.

As cyclic polyolefin resin, various products are marketed. As a specific example, the brand names "Xeonex", "Zeonoa" by the Japan Xeon Corporation, the brand name "Aton" by JSR Corporation, the brand name "Topas" by TICONA, and the brand name "APEL" by Mitsui Chemicals, Inc. are mentioned. .

As (meth) acrylic-type resin, Tg (glass transition temperature) becomes like this. Preferably it is 115 degreeC or more, More preferably, it is 120 degreeC or more, More preferably, it is 125 degreeC or more, Especially preferably, it is 130 degreeC or more. When Tg is 115 degreeC or more, it can become the thing excellent in the durability of a polarizing plate. Although the upper limit of Tg of the said (meth) acrylic-type resin is not specifically limited, From a viewpoint of moldability etc., Preferably it is 170 degrees C or less. From (meth) acrylic-type resin, the film whose in-plane phase difference Re and thickness direction phase difference Rth are almost zero can be obtained.

As (meth) acrylic-type resin, arbitrary appropriate (meth) acrylic-type resin can be employ | adopted within the range which does not impair the effect of this invention. For example, poly (meth) acrylic acid esters, such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-methyl ester- (Meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer (MS resin, etc.), a polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl copolymer, methyl methacrylate) -(Meth) acrylic acid norbornyl copolymer, etc.) are mentioned. Preferably, poly (meth) acrylic-acid C1-6 alkyl, such as polymethyl (meth) acrylate, is mentioned. More preferably, methyl methacrylate resin which has methyl methacrylate as a main component (50-100 weight%, Preferably 70-100 weight%) is mentioned.

As a specific example of (meth) acrylic-type resin, For example, Mitsubishi Rayon Co., Ltd. Acripet VH, Acripet VRL20A, (meth) acrylic system which has a ring structure in the molecule | numerator of Unexamined-Japanese-Patent No. 2004-70296 is mentioned. And a high Tg (meth) acrylic resin system obtained by resin, intramolecular crosslinking or intramolecular cyclization reaction.

As (meth) acrylic-type resin, you may use (meth) acrylic-type resin which has lactone ring structure. It is because it has high mechanical strength by high heat resistance, high transparency, and biaxial stretching.

As (meth) acrylic-type resin which has a lactone ring structure, Unexamined-Japanese-Patent No. 2000-230016, Unexamined-Japanese-Patent No. 2001-151814, Unexamined-Japanese-Patent No. 2002-120326, Unexamined-Japanese-Patent No. 2002-254544, Japan Unexamined Patent (Meth) acrylic resin which has a lactone ring structure as described in Unexamined-Japanese-Patent No. 2005-146084 etc. is mentioned.

The (meth) acrylic resin having a lactone ring structure preferably has a structure of a ring represented by the following General Formula (Formula 1).

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. In addition, the organic residue may contain an oxygen atom.

The content ratio of the lactone ring structure represented by General Formula (Formula 1) in the structure of the (meth) acrylic resin having a lactone ring structure is preferably 5 to 90% by weight, more preferably 10 to 70% by weight, further Preferably it is 10 to 60 weight%, Especially preferably, it is 10 to 50 weight%. When the content rate of the lactone ring structure represented by General formula (Formula 1) is less than 5 weight% among the structures of (meth) acrylic-type resin which has a lactone ring structure, there exists a possibility that heat resistance, solvent resistance, and surface hardness may become inadequate. When the content rate of the lactone ring structure represented by General formula (Formula 1) is more than 90 weight% among the structures of (meth) acrylic-type resin which has a lactone ring structure, there exists a possibility that molding workability may become inadequate.

The (meth) acrylic resin having a lactone ring structure has a mass average molecular weight (sometimes referred to as a weight average molecular weight), preferably 1000 to 2000000, more preferably 5000 to 1000000, still more preferably 10000 to 500000, Especially preferably, it is 50000-500000. If the mass average molecular weight is out of the above range, it is not preferable in view of moldability.

The (meth) acrylic resin having a lactone ring structure preferably has a Tg of 115 ° C or higher, more preferably 120 ° C or higher, still more preferably 125 ° C or higher, and particularly preferably 130 ° C or higher. Tg is 115 degreeC or more, for example, when it is attached to a polarizing plate as a transparent protective film, it becomes excellent in durability. Although the upper limit of Tg of (meth) acrylic-type resin which has the said lactone ring structure is not specifically limited, From a viewpoint of moldability etc., Preferably it is 170 degrees C or less.

The (meth) acrylic resin having a lactone ring structure is preferably higher as the total light transmittance measured by the method according to ASTM-D-1003, which is a molded article obtained by injection molding, is preferably 85% or more, and more. It is preferably at least 88%, more preferably at least 90%. Total light transmittance is a transparency standard, and there exists a possibility that transparency may fall when total light transmittance is less than 85%.

As for the said transparent protective film, that whose front phase difference is less than 40 nm and whose thickness direction phase difference is less than 80 nm is normally used. Front phase difference Re is represented by Re = (nx-ny) xd. Thickness direction phase difference Rth is represented by Rth = (nx-nz) xd. Moreover, Nz coefficient is represented by Nz = (nx-nz) / (nx-ny) [However, the refractive index of the slow axis direction, the fast axis direction, and the thickness direction of a film is set to nx, ny, nz, respectively, and d (Nm) is taken as the thickness of a film. The slow axis direction is set to the direction of the maximum refractive index in the film plane]. Moreover, it is preferable that a transparent protective film does not have coloring as much as possible. The protective film whose phase difference value of the thickness direction is -90 nm-+75 nm is used preferably. By using what is the phase difference value Rth of such a thickness direction is -90 nm-+75 nm, coloring (optical coloring) of the polarizing plate resulting from a transparent protective film can be almost eliminated. The thickness direction retardation value Rth is more preferably -80 nm to +60 nm, particularly preferably -70 nm to +45 nm.

On the other hand, a retardation plate having a phase difference of 40 nm or more and / or a thickness direction retardation of 80 nm or more may be used as the transparent protective film. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When using a retardation plate as a transparent protective film, since the said retardation plate also functions as a transparent protective film, thickness reduction can be attained.

Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. Although the thickness of a retardation plate is not specifically limited, either, about 20-150 micrometers is common.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, poly Sulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyphenylene sulfide, polyphenylene oxide, polyallyl sulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose resin, cyclic polyolefin resin (norbor Nene type resin) or these binary, tertiary various copolymers, a graft copolymer, a blend, etc. are mentioned. Such a polymeric raw material becomes an orientation substance (stretched film) by extending | stretching etc.

As a liquid crystal polymer, various main chain types, side chain types, etc. which the conjugated linear atomic group (mesogen) which gives liquid crystal aligning property were introduce | transduced into the main chain and side chain of a polymer are mentioned, for example. Specific examples of the main chain type liquid crystal polymer include, for example, a nematic oriented polyester liquid crystal polymer, a discotic polymer, a cholesteric polymer, and the like, in which a mesogenic group is bonded to a spacer portion providing flexibility. Specific examples of the side chain type liquid crystal polymer include a polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a para-substituted ring having a nematic orientation imparting effect through a spacer portion composed of a conjugated atom group as a side chain. The thing which has the mesogenic part which consists of a type compound unit, etc. are mentioned. These liquid crystal polymers develop a solution of a liquid crystalline polymer on an alignment treatment surface such as, for example, rubbing a thin film surface such as polyimide or polyvinyl alcohol formed on a glass plate, or depositing silicon oxide on all sides. It is carried out by heat treatment.

The retardation plate may have an appropriate retardation according to the purpose of use, for example, for the purpose of compensating coloring or vision due to birefringence of various wavelength plates and liquid crystal layers, or by laminating two or more kinds of retardation plates. The thing which controlled optical characteristics, such as these, may be sufficient.

The phase difference plate satisfies the relationship of nx = ny> nz, nx> ny> nz, nx> ny = nz, nx> nz> ny, nz = nx> ny, nz> nx> ny and nz> nx = ny. It selects and uses according to various uses. In addition, ny = nz includes not only the case where ny and nz are exactly the same, but also the case where ny and nz are substantially the same.

For example, in the retardation plate satisfying nx> ny> nz, it is preferable to use the thing which satisfy | fills 40-100 nm of front phase differences, 100-320 nm of thickness direction phase differences, and 1.8-4.5 Nz coefficients. For example, in the retardation plate (positive A plate) which satisfies nx> ny = nz, it is preferable to use what satisfy | fills 100-200 nm of front retardation. For example, in the retardation plate (negative A plate) which satisfies nz = nx> ny, it is preferable to use what satisfy | fills 100-200 nm of front retardation. For example, in the retardation plate which satisfies nx> nz> ny, it is preferable to use the thing which satisfy | fills 150-300 nm and Nz coefficient more than 0-0.7 with a front phase difference. As described above, for example, one that satisfies nx = ny> nz, nz> nx> ny, or nz> nx = ny can be used.

A transparent protective film can be suitably selected according to the liquid crystal display device applied. For example, in the case of VA (including VerticalAlignment, MVA, and PVA), it is preferable that at least one side (cell side) of the polarizing plate has a phase difference. It is preferable that it is the range of Re = 0-240 nm and Rth = 0-500 nm as a specific phase difference. In terms of three-dimensional refractive index, it is preferable that nx> ny = nz, nx> ny> nz, nx> nz> ny, and nx = ny> nz (one axis, two axes, Z-axis, negative C plate). When using a polarizing plate up and down of a liquid crystal cell, the upper and lower sides of a liquid crystal cell may have a phase difference, or any one of the upper and lower transparent protective films may have a phase difference.

For example, in the case of IPS (In-Plane Switching, FFS is included), when the transparent protective film of the one side of a polarizing plate has a phase difference, all can be used when it does not have. For example, when it does not have a phase difference, it is preferable that the upper and lower sides (cell side) of a liquid crystal cell do not have a phase difference. In the case of having a phase difference, when the upper and lower sides of the liquid crystal cell both have a phase difference, it is preferable that either of the upper and lower sides has a phase difference (for example, when Z is at the upper side and there is no phase difference at the lower side, or the upper side On A plate, on the lower side if positive C plate). When it has a phase difference, the range of Re = -500-500 nm and Rth = -500-500 nm is preferable. In terms of three-dimensional refractive index, nx> ny = nz, nx> nz> ny, nz> nx = ny, nz> nx> ny (uniaxial, Z-shaped, positive C plate, positive A plate) are preferable.

In addition, the film having the retardation may be attached separately to the transparent protective film having no retardation to impart the above function.

The polarizer and the transparent protective film may be subjected to a surface modification treatment before coating the adhesive. Specific treatments include corona treatment, plasma treatment, primer treatment, saponification treatment, treatment with a coupling agent, and the like.

The surface which does not adhere | attach the polarizer of the said transparent protective film may be the thing which performed the process for the purpose of a hard-coat layer, an antireflection process, sticking prevention, and diffused or anti glare.

The hard coat treatment is carried out for the purpose of preventing scratches on the surface of the polarizing plate, for example, a method of adding a cured film having excellent hardness, sliding properties, etc., by suitable ultraviolet curable resins such as acrylic or silicone, to the surface of the transparent protective film. Or the like. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the prior art. In addition, the sticking prevention treatment is performed for the purpose of preventing adhesion with an adjacent layer (for example, a diffuser plate on the backlight side).

In addition, antiglare treatment is performed for the purpose of preventing external light from being reflected from the surface of the polarizing plate and impairing the visibility of the transmitted light of the polarizing plate, for example, a roughening method using a sand blasting method or an embossing method. The compounding method of transparent fine particles, etc. can be formed by giving a fine uneven structure to the surface of a transparent protective film in a suitable method. As the fine particles to be included in the formation of the surface fine uneven structure, for example, conductive inorganic materials composed of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide and the like having an average particle diameter of 0.5 to 20 µm Transparent fine particles, such as organic type microparticles | fine-particles which consist of microparticles | fine-particles, a crosslinked or uncrosslinked polymer, etc. are used. When forming a surface fine uneven structure, the usage-amount of microparticles | fine-particles is generally about 2-70 weight part with respect to 100 weight part of transparent resin which forms a surface fine uneven structure, and 5-50 weight part is preferable. The antiglare layer may also have a diffusion layer (visual magnification function, etc.) for diffusing the polarizing plate transmitted light to enlarge the time and the like.

The antireflection layer, the anti-sticking layer, the diffusion layer, the antiglare layer, and the like can be formed on the transparent protective film itself, and can be formed separately from the transparent protective film as an optical layer.

The polarizing plate of this invention is manufactured by attaching a transparent protective film and a polarizer using the said adhesive agent. The said manufacturing method is a process of coating the said adhesive agent on the surface which forms the said adhesive bond layer of a polarizer, and / or the surface which forms the said adhesive bond layer of a transparent protective film; Attaching a polarizer and a transparent protective film through said adhesive for polarizing plates; And irradiating an active energy ray (electron beam, ultraviolet rays, etc.) with respect to the polarizer and the transparent protective film which were made to adhere through the said adhesive agent for polarizing plates, and forming an adhesive bond layer.

The coating method of an adhesive agent is suitably selected according to the viscosity of an adhesive agent, and the thickness made into the objective. As an example of a coating system, a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a load coater, etc. are mentioned, for example. In addition, methods, such as a dipping method, can be used suitably for coating.

A polarizer and a transparent protective film are affixed through the adhesive agent coated as mentioned above. Attachment of a polarizer and a transparent protective film can be performed by a roll laminator etc.

After attaching a polarizer and a transparent protective film, an active energy ray (electron beam, an ultraviolet-ray, etc.) is irradiated to harden an adhesive agent. The irradiation direction of an active energy ray (electron beam, ultraviolet rays, etc.) can be irradiated from arbitrary appropriate directions. Preferably, it irradiates from the transparent protective film side. When irradiated from the polarizer side, there exists a possibility that a polarizer may deteriorate by active energy rays (electron beam, an ultraviolet-ray, etc.).

It is preferable to use an active energy ray hardening-type adhesive agent as an electron beam hardening type. Arbitrary suitable conditions can be employ | adopted as long as the irradiation conditions of an electron beam can harden the said adhesive agent. For example, the electron beam irradiation preferably has an acceleration voltage of 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, the electron beam may not reach the adhesive, resulting in insufficient curing. If the accelerating voltage exceeds 300 kV, the penetration force through the sample may be too strong, causing the electron beam to pop out, resulting in damage to the transparent protective film or polarizer. There is a concern. As irradiation dose, it is 5-100 kGy, More preferably, it is 10-75 kGy. When the radiation dose is less than 5 kGy, the adhesive is insufficient to be cured, and when it exceeds 100 kGy, damage is caused to the transparent protective film or the polarizer, resulting in a decrease in mechanical strength or yellowing, and thus the predetermined optical properties cannot be obtained.

When hardening by ultraviolet irradiation, 0.1-5 weight part of polymerization initiators, Preferably 1-4 weight part, More preferably, 2-3 weight part is mix | blended with respect to 100 weight of curable components. Arbitrary appropriate conditions can be employ | adopted if the irradiation conditions of an ultraviolet-ray are conditions which can harden the said adhesive agent. It is preferable that it is 100-500mJ, and, as for the irradiation amount of an ultraviolet-ray, it is more preferable that it is 200-400mJ.

The thickness of the adhesive bond layer in the polarizing plate of this invention obtained as mentioned above is 0.01-7 micrometers. Preferably it is 0.01-5 micrometers, More preferably, it is 0.01-2 micrometers, More preferably, it is 0.01-1 micrometer. If the thickness is thinner than 0.01 mu m, the cohesive force of the adhesive force itself cannot be obtained, and there is a fear that the adhesive strength cannot be obtained. When the thickness of the adhesive layer exceeds 7 µm, the polarizing plate may not satisfy the durability.

Moreover, it is preferable that an adhesive bond layer satisfies durability that a gel fraction is 50 weight% or more. It is preferable that it is 60 weight% or more, and, as for a gel fraction, it is preferable that it is 70 weight% or more. In addition, a gel fraction is measured by the method as described in an Example.

Electron beam irradiation is usually irradiated in an inert gas, but if necessary, may be carried out in the atmosphere or under a condition of introducing a little oxygen. Depending on the material of the transparent protective film, by introducing oxygen appropriately, oxygen inhibition may be generated on the surface of the transparent protective film to which the electron beam first touches, thereby preventing damage to the transparent protective film, and efficiently irradiating the electron beam only to the adhesive. Can be.

When the above production method is carried out in a continuous line, the line speed depends on the curing time of the adhesive, but is preferably 1 to 500 m / min, more preferably 5 to 300 m / min, still more preferably 10 to 100 m / min. to be. When the line speed is too small, the productivity is insufficient, or the damage to the transparent protective film is too large to produce a polarizing plate that can withstand the durability test or the like. If the line speed is too large, curing of the adhesive may be insufficient, and the desired adhesiveness may not be obtained.

The polarizing plate of this invention can be used as an optical film laminated | stacked with the other optical layer at the time of practical use. Although it does not specifically limit about the optical layer, For example, in formation of a liquid crystal display device, such as a reflecting plate, a semi-transmissive plate, a retardation plate (including wavelength plates, such as 1/2 and a quarter), a visual compensation film, etc. The optical layer which may be used can use 1 layer or 2 or more layers. In particular, a reflection type polarizing plate or a semi-transmissive polarizing plate in which a reflecting plate or a semi-transmissive reflecting plate is laminated on the polarizing plate of the present invention, an elliptical polarizing plate or circular polarizing plate in which a phase difference plate is further laminated on the polarizing plate, and a visual compensation film is further laminated on the polarizing plate. The polarizing plate in which the brightness improvement film is further laminated | stacked on the wide viewing angle polarizing plate which consists of, or a polarizing plate is preferable.

The reflective polarizer is formed by forming a reflective layer on the polarizer, and is used to form a liquid crystal display device of a type that reflects and displays incident light from the viewing side (display side). It has advantages such as easy thinning of the liquid crystal display device. Formation of a reflective polarizing plate can be performed by a suitable method, such as the method of laying a reflective layer which consists of metal etc. on the single side | surface of a polarizing plate through a transparent protective layer etc. as needed.

As a specific example of a reflective polarizing plate, what provided the reflective layer by laying the foil and vapor deposition film which consist of reflective metals, such as aluminum, on the single side | surface of the transparent protective film which carried out the mat process as needed. Moreover, what contains microparticles | fine-particles in the said transparent protective film to make surface fine concavo-convex structure, and has a reflective layer of a fine concavo-convex structure on it, etc. are mentioned. The reflective layer of the fine uneven structure has the advantage of preventing the unevenness of light and shade by preventing incident light by diffusing the incident light by diffuse reflection. Moreover, the transparent protective film containing microparticles | fine-particles also has the advantage of being able to spread | diffuse when incident light and its reflected light transmit it, and to suppress a light and shade nonuniformity more. The formation of the reflective layer of the finely uneven structure reflecting the surface finely uneven structure of the transparent protective film is, for example, transparent protection of the metal in a manner suitable for deposition or plating such as vacuum deposition, ion plating or sputtering. It can carry out by the method of directly laying on the surface of a layer.

Instead of the method of directly applying to the transparent protective film of the above-mentioned polarizing plate, a reflecting plate can also be used as a reflecting sheet etc. which form a reflecting layer in the appropriate film based on the said transparent film. In addition, since the reflective layer is usually made of a metal, the use form in which the reflective surface is covered with a transparent protective film, a polarizing plate, or the like prevents the reduction of the reflectance by oxidation, and furthermore, the surface of the long-term sustaining of the initial reflectance or the protective layer. It is preferable in terms of avoiding the separate laying of.

In addition, a semi-transmissive polarizing plate can be obtained by making it the semi-transmissive reflective layer, such as the half mirror which reflects light in the reflective layer and permeate | transmits in the above. The semi-transmissive polarizing plate is usually formed on the back side of the liquid crystal cell, and when the liquid crystal display device or the like is used in a relatively bright atmosphere, the incident light from the viewing side (display side) is reflected to display an image and relatively In a dark atmosphere, a liquid crystal display device of a type for displaying an image and the like can be formed by using a built-in light source such as a backlight built in the back side of the transflective polarizing plate. That is, the transflective polarizing plate can save energy of using a light source such as a backlight in a bright atmosphere, and is useful for forming a liquid crystal display device of the type that can be used using a built-in light source even in a relatively dark atmosphere.

An elliptical polarizing plate or circular polarizing plate in which a retardation plate is further laminated on the polarizing plate will be described. A retardation plate or the like is used to change linearly polarized light into elliptical polarization or circularly polarized light, to change elliptical polarization or circularly polarized light into linearly polarized light, or to change the polarization direction of linearly polarized light. In particular, a so-called quarter wave plate (also referred to as λ / 4 plate) is used as the phase difference plate which changes linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light. A half wave plate (also called a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

The elliptical polarizing plate is effectively used for compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device, for displaying black and white without coloration. In addition, controlling the three-dimensional refractive index is preferable because it can compensate (prevent) the coloration generated when the screen of the liquid crystal display device is viewed in the oblique direction. The circularly polarizing plate is effectively used, for example, in the case of arranging the color tone of an image of a reflection type liquid crystal display device in which an image is a color display, and also has a function of antireflection. Specific examples of the retardation plate described above include birefringence formed by stretching a film made of a suitable polymer such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene or other polyolefins, polyarylates, and polyamides. The thing which supported the orientation film of a film, a liquid crystal polymer, and the orientation layer of a liquid crystal polymer with a film, etc. are mentioned. The retardation plate may be any one having a suitable retardation according to the purpose of use, for example, for the purpose of compensating coloring or vision due to birefringence of various wavelength plates and liquid crystal layers, or by laminating two or more kinds of retardation plates. The optical characteristic of this may be controlled.

Moreover, said elliptical polarizing plate and reflective elliptic polarizing plate laminate | stack a polarizing plate or a reflection type polarizing plate, and a phase difference plate by a suitable combination. Such elliptical polarizing plates and the like can also be formed by sequentially stacking them separately in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. It is excellent in the stability of quality, lamination | stacking workability, etc., and there exists an advantage which can improve manufacturing efficiency, such as a liquid crystal display device.

The visual compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. As such a visual compensation retardation plate, it consists of an orientation film, such as a liquid crystal polymer, on an orientation film, such as a retardation film and a liquid crystal polymer, or a transparent base material. The conventional retardation plate is a polymer film having birefringence stretched in one plane in the plane direction, whereas the retardation plate used as a visual compensation film is a polymer film having birefringence stretched in the plane direction in two directions. Or a bidirectional stretched film such as a birefringent polymer or a diagonally oriented film, which has a refractive index in the thickness direction that is stretched in one plane in the plane direction and also in the thickness direction, is used. As a diagonal oriented film, the thing which carried out the extending | stretching process and / or shrinkage | contraction processing of the polymer film under the action of the shrinkage force by heating, for example, adhere | attached the heat-shrink film to a polymer film, and the thing which orientated the liquid crystal polymer obliquely, etc. are mentioned. As the raw material polymer of the retardation plate, the same polymer as described in the above retardation plate is used, and for the purpose of preventing the coloring due to the change of the viewing angle based on the phase difference by the liquid crystal cell, the expansion of the viewing angle with good visibility, etc. One suitable one can be used.

Moreover, the optical compensation retardation plate which supported the optically anisotropic layer which consists of the alignment layer of a liquid crystal polymer, especially the diagonal alignment layer of a discotic liquid crystal polymer, especially at the point of achieving a wide viewing angle with good visibility can be used preferably. .

The polarizing plate which affixed the polarizing plate and a brightness improving film is normally provided in the back side of a liquid crystal cell, and is used. The brightness enhancement film exhibits a property of reflecting linearly polarized light on a predetermined polarization axis or circularly polarized light in a predetermined direction when natural light is incident by a backlight such as a liquid crystal display device or reflection from the back side, and transmitting other light. The polarizing plate laminated | stacked with the polarizing plate injects light from a light source, such as a backlight, and obtains the transmitted light of a predetermined polarization state, and light other than the said predetermined polarization state is reflected without being transmitted. The light reflected from the surface of the brightness enhancing film is further inverted through a reflecting layer or the like formed on the rear side thereof, and reentered into the brightness enhancing film, and part or all of the light is transmitted as light in a predetermined polarization state to transmit light of the brightness enhancing film. The brightness can be improved by increasing the amount of light and increasing the amount of light that can be used for liquid crystal display image display by supplying polarized light that is hardly absorbed by the polarizer. That is, when light is made to pass through a polarizer from the back side of a liquid crystal cell with a backlight etc. without using a brightness improving film, the light which has a polarization direction which does not correspond to the polarization axis of a polarizer is absorbed by a polarizer almost, It does not pass through the polarizer. That is, although it changes also with the characteristic of the polarizer used, about 50% of light is absorbed by a polarizer, and the quantity of light which can be used for a liquid crystal image display etc. decreases by that amount, and an image becomes dark. The brightness enhancement film repeatedly reflects light having a polarization direction absorbed by the polarizer in the brightness enhancement film without incident on the polarizer, and is then inverted through a reflective layer or the like formed on the back side and reincident to the brightness enhancement film. Since only the polarization direction in which the polarization direction of the light reflected and inverted between the two becomes the polarization direction that can pass through the polarizer is transmitted, the brightness enhancement film is transmitted to the polarizer, so that light such as a backlight can be efficiently used for image display of the liquid crystal display device. Can brighten the screen.

A diffusion plate may be provided between the brightness enhancing film and the reflective layer. The light in the polarization state reflected by the brightness enhancement film is directed to the reflection layer or the like, but the diffuser plate provided uniformly diffuses the light passing therethrough and at the same time resolves the polarization state to become a non-polarization state. In other words, the diffusion plate returns the polarized light to the original natural light state. The light in this non-polarization state, that is, in the natural light state, is directed toward the reflection layer or the like, is reflected through the reflection layer or the like, and passes through the diffuser plate again and is reincident to the brightness enhancement film. By providing a diffuser plate that returns the polarization to the original natural light state between the brightness enhancing film and the reflective layer, the brightness of the display screen can be maintained, while at the same time reducing the unevenness of the brightness of the display screen to provide a uniform and bright screen. have. By providing such a diffuser plate, it is considered that the number of times of repeated reflection of the first incident light can be appropriately increased to provide a uniform bright display screen with the diffuser function of the diffuser plate.

As said brightness improving film, the cholesteric which shows the characteristic which permeate | transmits linearly polarized light of a predetermined polarization axis | shaft and reflects other light, such as the multilayered laminated body of a dielectric thin film and the thin film film from which refractive index anisotropy differs, for example, is a cholesteric Suitable ones, such as those in which the circularly polarized light of any one of left rotation or right rotation is reflected and other light transmits, such as an alignment film of the liquid crystal polymer and the alignment liquid crystal layer supported on the film substrate, can be used.

Therefore, in the luminance improvement film of the type which permeate | transmits linearly polarized light of the said predetermined polarization axis, it can transmit efficiently, suppressing the absorption loss by a polarizing plate by making the transmitted light into a polarizing plate as it is, and making it enter. On the other hand, in the luminance-enhancing film of the type which transmits circularly polarized light like a cholesteric liquid crystal layer, although it can be made to enter a polarizer as it is, the circularly polarized light is linearly polarized through a phase difference plate in order to suppress absorption loss, and a polarizing plate It is preferable to make it enter. Further, by using a quarter wave plate as the retardation plate, circularly polarized light can be converted into linearly polarized light.

The retardation plate which functions as a quarter wave plate in a wide wavelength range of a visible range etc., for example, is a phase difference layer which functions as a quarter wave plate with respect to pale light of wavelength 550nm, and the phase difference layer which shows another phase difference characteristic. For example, it can obtain by the method of superimposing the retardation layer which functions as a 1/2 wave plate. Therefore, the phase difference plate arrange | positioned between a polarizing plate and a brightness improving film may consist of one layer or two or more phase difference layers.

Moreover, also about a cholesteric liquid crystal layer, when it is set as the arrangement structure which overlapped two or three layers by the combination of a thing with a different reflection wavelength, what reflects circularly polarized light in a wide wavelength range, such as a visible light region, can be obtained there Based on the above, transmission circularly polarized light in a wide wavelength range can be obtained.

Moreover, the polarizing plate may consist of what laminated | stacked the polarizing plate and two or three or more optical layers like the said polarization split type polarizing plate. Therefore, the reflective elliptically polarizing plate, the semi-transmissive elliptically polarizing plate, etc. which combined said reflective polarizing plate, semi-transmissive polarizing plate, and retardation plate may be sufficient.

The optical film in which the optical layer is laminated on the polarizing plate may be formed by a method of laminating them sequentially in a manufacturing process such as a liquid crystal display device, but the preliminary lamination to the optical film has excellent quality stability and assembly work. There is an advantage that the manufacturing process such as a liquid crystal display device can be improved. Appropriate adhesion means, such as an adhesion layer, can be used for lamination. At the time of adhering the polarizing plate or the other optical film, the optical axis can be set to an appropriate placement angle in accordance with a desired phase difference characteristic or the like.

The adhesive layer for adhering to the polarizing plate mentioned above and the optical film which has laminated | stacked at least 1 layer of polarizing plates with other members, such as a liquid crystal cell, can also be provided. The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, but for example, an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine-based or a rubber-based polymer may be appropriately selected and used. Can be. In particular, an acrylic adhesive has excellent optical transparency, exhibits moderate wettability, cohesiveness, and adhesive adhesion characteristics, and has excellent weather resistance, heat resistance, and the like, and can be preferably used.

In addition to the above, in terms of prevention of foaming and peeling phenomenon due to moisture absorption, reduction of optical properties due to thermal expansion difference, prevention of warping of liquid crystal cells, and furthermore, formation of a high quality and durable liquid crystal display device, The adhesive layer which has low moisture absorption and excellent heat resistance is preferable.

The pressure-sensitive adhesive layer may be, for example, a resin such as a natural product or a synthetic material, particularly a pressure-sensitive adhesive layer such as a filler, a pigment, a colorant, an antioxidant, or the like made of a tackifying resin, glass fiber, glass beads, metal powder, or other inorganic powder. You may contain the additive of what is added. Moreover, the adhesion layer etc. which contain microparticles | fine-particles and show light diffusivity may be sufficient.

Laying of the adhesion layer with respect to the single side | surface or both surfaces of a polarizing plate or an optical film can be performed by a suitable method. As an example, about 10 to 40 weight% of the adhesive solution which melt | dissolved or disperse | distributed or disperse | distributed a base polymer or its composition in the solvent which consists of a single substance or mixture of the appropriate solvents, such as toluene and ethyl acetate, is prepared, The method of laying out directly on a polarizing plate or an optical film by appropriate development methods, such as a coating system, or the method of forming an adhesion layer on a separator according to the above, and transferring it on a polarizing plate or an optical film, etc. are mentioned.

The pressure-sensitive adhesive layer may be formed on one side or both sides of a polarizing plate or an optical film as an overlap layer of things such as different compositions or kinds. Moreover, when formed in both surfaces, it can also be set as adhesive layers, such as a different composition, a kind, thickness, etc. in the front and back of a polarizing plate and an optical film. The thickness of an adhesion layer can be suitably determined according to a purpose of use, adhesive force, etc., Generally, it is 1-40 micrometers, 5-30 micrometers is preferable, and 10-25 micrometers is especially preferable. When it is thinner than 1 µm, the durability deteriorates, and when it is thicker than 40 µm, lifting or peeling due to foaming or the like tends to occur, resulting in poor appearance.

The exposed surface of the pressure-sensitive adhesive layer is temporarily covered with a separator for the purpose of preventing contamination thereof until it is provided for practical use. Thereby, contact with an adhesion layer can be prevented in a usual handling state. As the separator, except for the above thickness conditions, for example, a plastic film, a rubber sheet, a paper, a cloth, a nonwoven fabric, a net, a foam sheet, a metal foil, a suitable thin body such as laminates thereof, silicone-based or long-chain alkyl-based, An appropriate one according to the prior art, such as a coat treatment with an appropriate release agent such as fluorine or molybdenum sulfide, can be used.

In order to improve the adhesiveness between a polarizing plate and an adhesive layer, you may provide an anchor layer between the layers.

As a forming material of the said anchor layer, Preferably, the anchor agent chosen from polyurethane, polyester, and the polymer containing an amino group in a molecule | numerator is used, Especially preferably, it is a polymer containing an amino group in a molecule | numerator. Polymers containing an amino group in a molecule ensure good adhesion because the amino group in the molecule exhibits an interaction such as a carboxyl group or the like in the pressure-sensitive adhesive or an ionic interaction.

As polymers containing amino groups in the molecule, for example, polymers of amino group-containing monomers such as polyethyleneimine, polyallylamine, polyvinylamine, polyvinylpyridine, polyvinylpyrrolidine, dimethylaminoethylacrylate, and the like Can be mentioned.

An antistatic agent can also be added to the said anchor layer in order to provide antistatic property. Examples of antistatic agents for imparting antistatic properties include conductive polymers such as ionic surfactants, polyaniline, polythiophene, polypyrrole, and polyquinoxaline, and metal oxides such as tin oxide, antimony oxide, and indium oxide. However, the conductive polymer type is preferably used in view of optical properties, appearance, antistatic effect, and stability at the time of heating and humidifying the antistatic effect. Among these, water-soluble conductive polymers such as polyaniline and polythiophene or water-dispersible conductive polymers are particularly preferably used. When water-soluble conductive polymers or water-dispersible conductive polymers are used as the material for forming the antistatic layer, deterioration of the optical film substrate by the organic solvent during coating can be suppressed.

In the present invention, for example, a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, or a cyan to each layer such as a polarizer, a transparent protective film or an optical film forming the polarizing plate, or an adhesive layer. The thing which gave ultraviolet absorbing power etc. according to methods, such as a process with ultraviolet absorbers, such as a noacrylate type compound and a nickel complex salt type compound, may be sufficient.

The polarizing plate or optical film of this invention can be used suitably for formation of various apparatuses, such as a liquid crystal display device. Formation of a liquid crystal display device can be performed according to the prior art. That is, the liquid crystal display device is generally formed by appropriately assembling a component such as a liquid crystal cell, a polarizing plate or an optical film, and an illumination system as necessary, and mounting a driving circuit, but in the present invention, the polarizing plate according to the present invention. Or there is no limitation in particular except the point which uses an optical film, and it can follow conventionally. Also about a liquid crystal cell, what is arbitrary types, such as a TN type, STN type, pi type, VA type, IPS type, can be used, for example.

A suitable liquid crystal display device, such as a liquid crystal display device in which a polarizing plate or an optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or reflecting plate used in an illumination system, can be formed. In that case, the polarizing plate or optical film by this invention can be provided in the one side or both sides of a liquid crystal cell. When providing a polarizing plate or an optical film in both sides, they may be the same and may differ. At the time of formation of the liquid crystal display device, for example, a diffuser plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, or the like and a suitable component at one or two or more layers in appropriate positions. Can be placed.

Next, an organic electroluminescent device (organic EL display device) will be described. In general, an organic EL display device forms a light emitting body (organic electroluminescent light emitting body) by sequentially stacking a transparent electrode, an organic light emitting layer, and a metal electrode on a transparent substrate. Here, the organic light emitting layer is a laminate of various organic thin films, for example, a hole injection layer made of a triphenylamine derivative or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, or such a light emitting layer and a perylene derivative. The structure which has various combinations, such as the laminated body of the electron injection layer which consists of these etc., or these laminated bodies of a hole injection layer, a light emitting layer, and an electron injection layer is known.

In the organic EL display device, by applying a voltage to the transparent electrode and the metal electrode, holes and electrons are injected into the organic light emitting layer, and energy generated by the recombination of these holes and electrons excites the fluorescent material, and the excited fluorescent material It emits light on the principle of emitting light when returning to the ground state. The mechanism of intermediate recombination is the same as that of a general diode, and as can be expected from this point, the current and the emission intensity exhibit strong nonlinearity accompanied by rectification with respect to the applied voltage.

In the organic EL display device, at least one electrode must be transparent in order to extract light from the organic light emitting layer, and a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO) is usually used as an anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and metal electrodes such as Mg-Ag and Al-Li are usually used.

In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer also transmits light almost completely like the transparent electrode. As a result, light incident on the surface of the transparent substrate during non-emission, and transmitted through the transparent electrode and the organic light emitting layer and reflected by the metal electrode again comes out to the surface side of the transparent substrate, therefore, when viewed from the outside, the organic EL display device The display surface of looks like a mirror.

An organic EL display device comprising an organic electroluminescent light-emitting body comprising a transparent electrode on the front side of an organic light emitting layer that emits light by application of a voltage and a metal electrode on the back side of the organic light emitting layer, wherein the organic EL display device is transparent. While providing a polarizing plate on the surface side of an electrode, a phase difference plate can be provided between these transparent electrodes and a polarizing plate.

Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected on the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, when the phase difference plate is constituted by a quarter wave plate, and the angle between the polarization direction of the polarizing plate and the phase difference plate is adjusted to π / 4, the mirror surface of the metal electrode can be completely shielded.

That is, only the linearly polarized light component is transmitted to the external light incident on the organic EL display device by the polarizing plate. This linearly polarized light is generally elliptically polarized by the retardation plate, but in particular, when the retardation plate is a quarter wave plate and the angle between the polarization direction of the polarizing plate and the retardation plate is? / 4, it becomes circularly polarized light.

The circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, passes through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot transmit a polarizing plate. As a result, the mirror surface of a metal electrode can be shielded completely.

Example

Although the Example of this invention is described below, embodiment of this invention is not limited to these.

<Tg: glass transition temperature>

It measured at the temperature increase rate of 10 degree-C / min using the glass transition point temperature differential scanning calorimeter (DSC). The sample was used by crimping 5 mg of samples in the aluminum press lid container.

<Gel fraction>

Using an applicator, the adhesive used in each example was coated on the release film, and another release film was attached thereon, and then the electron beam was irradiated under the same conditions as in each example to cure the adhesive to form an adhesive layer. . The release film was peeled off from both sides of the obtained adhesive bond layer, about 200 mg was taken out from the adhesive bond layer, this was weighed, and the weight (W1) was calculated | required. Subsequently, this was wrapped in a microporous tetrafluoroethylene membrane (film weight: W2), tied with a string, and immersed in about 50 ml of toluene for 4 days, and then the soluble component was extracted. This was dried in an oven at 110 ° C. for 1 hour to measure the total weight (W3). From this measurement, the gel fraction (weight%) of the adhesive layer was calculated | required according to the following formula.

Gel fraction (% by weight) = ((W3-W2) / W1) × 100

(Polarizer)

A polyvinyl alcohol film having an average degree of polymerization of 2400, a degree of saponification of 99.9 mol%, and a thickness of 75 µm was swelled by immersing in hot water at 30 ° C for 60 seconds. Next, it extended | stretched to 3.5 times, dyeing for 1 minute in 30 degreeC iodine solution of 0.3 weight% (weight ratio: iodine / potassium iodide = 0.5 / 8). Thereafter, the total draw ratio was stretched up to six times while immersing in a 4% by weight aqueous solution of boric ester at 65 ° C for 0.5 minute. After extending | stretching, it dried for 3 minutes in 70 degreeC oven, and obtained the polarizer of thickness 26micrometer. The moisture content of the polarizer was 13.5 weight%.

(Transparent protective film)

A lactonated polymethyl methacrylate film (LMMA, lactoneization rate 20%, thickness 30 μm, Re = 0 nm, Rth = 0 nm) was used.

(Phase difference value)

The measurement of the retardation value was nx and ny measured with respect to the value of wavelength 590nm using the retarder (Oji Measurement Instruments Co., Ltd. product, product name "KOBRA21-ADH") based on the parallel Nicole rotation method. , from the value of nz and the film thickness (d), the front phase difference (Re) and the thickness direction phase difference (Rth, Nz) were calculated. However, the refractive indices of the slow axis direction, the fast axis direction, and the thickness direction of the film were respectively nx, It is set as ny and nz, and d (nm) is made into the thickness of a film. The slow axis direction is set to the direction of the maximum refractive index in the film plane.].

Example  One

(Adhesive: Curable Component)

N-acryloyl morpholine was used as an adhesive agent.

(Manufacture of Polarizing Plate)

On one side of the transparent protective film, the adhesive was a transparent protective film with an adhesive coated with a microgravure coater (gravure roll: # 180, rotation speed 140% / line speed) to a thickness of 5 μm. Subsequently, the transparent protective film with an adhesive agent was affixed on this from both surfaces of the said polarizer. The electron beam was irradiated from the transparent protective film side (both sides) which were affixed, and the polarizing plate which has a transparent protective film on both sides of a polarizer was obtained. The line speed was 20 m / min, the acceleration voltage was 250 kV, and the irradiation dose was 20 kGy. Tg was 140 degreeC and the gel fraction was 72 weight%.

Examples 2 to 21, Comparative Examples 1 to 11

In Example 1, when using together and the kind of curable component, the polarizing plate was obtained like Example 1 except having changed the ratio and thickness of an adhesive bond layer as shown in Table 1. In Comparative Examples 4 to 6, ultraviolet rays were irradiated with 300 mJ instead of electron beam irradiation. In Comparative Examples 4-6, 3 weight part of polymerization initiators were added and used for 100 weight part of curable components. In addition, the gravure roll has a mirror surface at 0.1 µm, 0.3 µm and 0.5 µm, # 300 at 0.8 µm and 1 µm, # 280 at 2 µm, # 280 at 3 µm and # 250, 4 µm and 4.2 µm It changed to # 180 at # 220, 5 micrometers, and 6 micrometers, and # 120 at 10 micrometers. Table 1 shows the Tg and the gel fraction of the adhesive layer in each example.

[evaluation]

The following evaluation was performed about the polarizing plates obtained by the Example and the comparative example. The results are shown in Table 1.

<Durability>

The obtained polarizing plate was cut | judged to the size of diagonal 15 inches, and it attached to both surfaces of the alkali free glass of 0.5 mm thickness in the direction of cross nicol with the acrylic adhesive, and manufactured the sample. The sample was charged under the following conditions.

Condition (1): -200 times of heat shock of -40-85 degreeC for 30 minutes each

Condition (2): 200 times of -30-70 degreeC heat shock for 30 minutes each

The polarizing plate state with time in each said condition was evaluated based on the following reference | standard.

◎: No crack

(Circle): The short crack of 5 mm or less has generate | occur | produced only in the edge part.

(Triangle | delta): The crack generate | occur | produced on the line | wire with a short place other than an edge part. However, the polarizing plate is not separated into two or more portions by the line.

X: The crack generate | occur | produced in places other than an edge part. The polarizing plate is separated into two or more parts by the line.

<Peel Strength>

The obtained polarizing plate was cut out to the size of 15 mm x 150 mm, and was used as a sample. The sample was affixed on the glass plate by the double-sided adhesive tape (Nitto Electric Co., Ltd. product, No. 500). In the sample (polarizing plate), the code | symbol was previously formed between a transparent protective film and a polarizer, and the code | symbol was precipitated by the variable angle peel tester (made by Asahi Seiko Co., Ltd.), and the peeling strength (N / 15mm) was measured. Measurement conditions were made into normal temperature (23 degreeC), peel angle: 90 degree, and peel speed: 3000 mm / min. Table 1 shows the average value of the data between 50 mm and 100 mm of the obtained measurement data.

In Table 1, ACMO: N-acryloyl morpholine, DA-141: 2-hydroxy-3-phenoxypropyl acrylate (made by Nagase Chemtex Co., Ltd., DA-141), HEAA: N-hydroxyethyl acryl Amide, N-MAN: N-methylol acrylamide, NIPAM: N-isopropyl acrylamide, EB: electron beam, UV: ultraviolet rays.

Claims (13)

As a polarizing plate in which the transparent protective film is formed in at least one surface of a polarizer through an adhesive bond layer, The adhesive layer is formed of an active energy ray curable adhesive containing at least one curable component, Tg of an adhesive bond layer is 60 degreeC or more, and, The thickness of an adhesive bond layer is 0.01-7 micrometers, The polarizing plate characterized by the above-mentioned. The method of claim 1, When Tg (degreeC) of an adhesive bond layer is defined as A, and the thickness (micrometer) of an adhesive bond layer is B, Equation (1): A-12 × B> 58, The polarizing plate which satisfies. The method of claim 1, The adhesive layer has a gel fraction of 50% by weight or more. The method of claim 1, The curable component is a compound which has a (meth) acryloyl group, The polarizing plate characterized by the above-mentioned. The method of claim 4, wherein As the curable component, General Formula (1): CH ₂ = C (R ¹ ) -CONR ² (R ³ ) (R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a hydroxyl group, a mercapto group, an amino group or A C1-C4 linear or branched alkyl group which may have a quaternary ammonium group, R <^3> represents a hydrogen atom or a C1-C4 linear or branched alkyl group, R <^2> , R Except when ³ is a hydrogen atom at the same time, or R <^2> , R <^3> combines and forms the 5-membered ring or 6-membered ring which may contain the oxygen atom), N-substituted amide type monomer represented by It comprises a polarizing plate. The method of claim 5, wherein The N-substituted amide monomer is at least one selected from N-hydroxyethyl acrylamide, N-methylol acrylamide, N-isopropyl acrylamide, and N-acryloyl morpholine. The method of claim 5, wherein The N-substituted amide monomer contains N-hydroxyethyl acrylamide and N-acryloyl morpholine, The polarizing plate characterized by the above-mentioned. The method of claim 7, wherein The ratio of N-hydroxyethyl acrylamide with respect to the total amount of N-hydroxyethyl acrylamide and N-acryloyl morpholine is 40 weight% or more, The polarizing plate characterized by the above-mentioned. The method of claim 4, wherein The curable component further contains a monofunctional (meth) acrylate having an aromatic ring and a hydroxyl group. The method of claim 1, An active energy ray-curable adhesive is an electron beam-curable adhesive. The method of claim 1, The transparent protective film is at least 1 selected from a cellulose resin, a polycarbonate resin, a cyclic polyolefin resin, and a (meth) acrylic resin, The polarizing plate characterized by the above-mentioned. At least one polarizing plate of Claim 1 is laminated | stacked, The optical film characterized by the above-mentioned. The polarizing plate of Claim 1 is used, The image display apparatus characterized by the above-mentioned.