TWI647476B - Polarizing plate, polarizing plate with adhesive and liquid crystal display device - Google Patents

Abstract

The present invention provides a polarizing plate in which a surface of a member that is in contact with a polarizing plate is not transferred (transferred) to a surface of a polarizing plate in a liquid crystal display device in which the polarizing plate has been laminated on a liquid crystal cell.

The polarizing plate of the present invention is attached to a single side surface of the absorbing polarizing film, and has a first protective film laminated thereon. The Vickers hardness of the surface of the first protective film on the opposite side to the absorbing polarizing film is 10 kgf. /mm ² or more. The first protective film may be a thermoplastic resin film. Further, the first protective film may be a reflective polarizing film. Further, the first protective film may be a laminate of a reflective polarizing film and a thermoplastic resin film, and laminated on the thermoplastic resin film side to the absorption-type polarizing film.

Description

Polarizing plate, polarizing plate with adhesive and liquid crystal display device

The present invention relates to a polarizing plate on a light source side, a polarizing plate with an adhesive attached thereto, and a liquid crystal display device.

The polarizing plate usually has a resin film formed on at least one side of the absorption type polarizing film, and is laminated on the resin film or an optical film instead of the resin film as needed. Then, the polarizing plate is combined with a liquid crystal cell or another member to constitute a liquid crystal display device (Patent Document 1). In the liquid crystal display device, the surface shape of another member that is in contact with the polarizing plate may be transferred to the surface of the polarizing plate, that is, "transfer". When the transfer occurs, since the trace of the transfer is seen when the image is displayed, there is a problem that the display quality is remarkably lowered.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2013-190779

An object of the present invention is to provide a polarizing plate which is less likely to cause the above-described transfer.

The present invention provides the following polarizing plate, a polarizing plate with an adhesive layer provided with an adhesive layer on the polarizing plate, and a liquid crystal display device to which the polarizing plate with an adhesive is applied.

[1] A polarizing plate is attached to a single side surface of an absorbing polarizing film, and a first protective film is laminated thereon, wherein a Vickers hardness of a surface of the first protective film on the opposite side to the absorbing polarizing film is 10kgf/mm ² or more.

[2] The polarizing plate according to [1], wherein the first protective film is a thermoplastic resin film.

[3] The polarizing plate according to [1], wherein the first protective film is a reflective polarizing film.

[4] The polarizing plate according to [1], wherein the first protective film is a laminate of a reflective polarizing film and a thermoplastic resin film, and is laminated on the thermoplastic resin film side to the absorption-type polarizing film.

[5] The polarizing plate according to any one of [1], wherein the one-side area layer of the absorbing polarizing film has a first protective film having a Vickers hardness of 10 kgf/mm ² or more on the outermost surface. There is a second protective film on the area layer on the other side.

[6] A polarizing plate with an adhesive, wherein an adhesive layer is formed on the side of the absorbing polarizing film of the polarizing plate according to any one of [1] to [4].

[7] A polarizing plate with an adhesive attached to the side of the second protective film of the polarizing plate according to [5], wherein an adhesive layer is formed.

[8] A liquid crystal display device in which a polarizing plate with an adhesive as described in [6] or [7] is laminated on a liquid crystal cell.

[9] The liquid crystal display device according to [8], wherein the polarizing plate with an adhesive is laminated on the side of the light source of the liquid crystal cell with the adhesive layer side.

According to the polarizing plate of the present invention, the Vickers hardness of the outermost surface of the polarizing plate (the surface of the protective film opposite to the absorption type polarizing film) is set to a constant value or more, and the polarizing plate is combined with other members to serve as a liquid crystal. When the device is displayed, transfer which occurs on the surface thereof is suppressed. Therefore, the liquid crystal display device of the present invention is excellent in display quality.

1‧‧‧Absorbing polarizing film

3‧‧‧First protective film

5‧‧‧Second protective film

10‧‧‧Polar plate

15‧‧‧Adhesive layer

20‧‧‧Polarizer with adhesive

25‧‧‧Polar plate (view side)

30‧‧‧Liquid Crystal Unit

40‧‧‧Light diffuser

50‧‧‧ Backlight

55‧‧‧Liquid crystal display device

60‧‧‧稜鏡 Patterns in an in-line manner 2 overlapping light diffusers

65‧‧‧Aluminum plate

Figs. 1(A) and 1(B) are schematic cross-sectional views showing an example of a layer configuration of a polarizing plate and a polarizing plate with an adhesive according to the present invention.

Figs. 2(A) and 2(B) are schematic cross-sectional views showing an example of a layer configuration of a liquid crystal display device of the present invention.

Fig. 3 is a schematic cross-sectional view showing the Vickers hardness of the polarizing plate.

<Absorbing polarizing film>

The polarizing plate has a protective film on one side or both sides of the absorption type polarizing film. Absorptive polarizing film is usually used for adsorption of polyvinyl alcohol resin film To those with dichroic pigments. The polyvinyl alcohol-based resin constituting the absorption-type polarizing film can be obtained by saponifying a polyvinyl acetate-based resin. The polyvinyl acetate-based resin is exemplified by a polyvinyl acetate which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith. Examples of the other monomer copolymerized with vinyl acetate include an unsaturated carboxylic acid, an olefin, a vinyl ether, an unsaturated sulfonic acid, an acrylamide having an ammonium group, and the like. The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more.

The polyvinyl alcohol-based resin can be further modified. For example, an aldehyde-modified polyvinyl formal or polyvinyl acetal can be used. Further, the degree of polymerization of the polyvinyl alcohol-based resin is usually from about 1,000 to 10,000, preferably from about 1,500 to 5,000. Specific examples of the polyvinyl alcohol-based resin and the dichroic dye include a polyvinyl alcohol-based resin and a dichroic dye exemplified in JP-A-2012-159778.

A product obtained by forming a polyvinyl alcohol-based resin into a film is a raw material film which is used as an absorption-type polarizing film. The method of forming the film of the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a known method. The thickness of the raw material film formed of the polyvinyl alcohol-based resin is not particularly limited, and is, for example, 150 μm or less. The film thickness is preferably 3 μm or more, and preferably 75 μm or less, if the ease of stretching or the like is also considered.

The absorption-type polarizing film can be formed by, for example, stretching a step of stretching a polyvinyl alcohol-based resin film on one axis, and dyeing the polyvinyl alcohol-based resin film with a dichroic dye to adsorb the dichroic dye. Step of treating a polyvinyl alcohol-based resin film having a dichroic dye with an aqueous solution of boric acid The step of washing with water after the treatment of the boric acid aqueous solution is finally carried out by drying it. Further, the absorption type polarizing film can be produced, for example, according to the method described in JP-A-2012-159778. In this method, a polyvinyl alcohol-based resin layer as an absorption-type polarizing film can be formed by coating a base material film with a polyvinyl alcohol-based resin. The thickness of the absorptive polarizing film is usually from 2 to 40 μm, preferably from about 3 to 30 μm.

<First Protective Film>

The polarizing plate is provided with a first protective film on at least one area of the absorption type polarizing film. The polarizing plate of the present invention may have a first protective film on at least one side of the absorbing polarizing film. As shown in FIG. 1, the first protective film 3 may be provided only on one side of the absorbing polarizing film 1. [Fig. 1(A)], the first protective film 3 may be laminated on one side of the absorbing polarizing film 1, and the second protective film 5 may be laminated on the other side (Fig. 1(B)).

The first protective film 3 which is laminated on one side of the absorbing polarizing film may, for example, be a thermoplastic resin film formed of a thermoplastic resin, a reflective polarizing film, a laminate of a reflective polarizing film and a thermoplastic resin film, or the like.

(thermoplastic resin film)

The thermoplastic resin film formed of a thermoplastic resin is preferably made of a resin excellent in transparency, uniform optical properties, mechanical strength, thermal stability, and the like. Specific examples of the thermoplastic resin include cellulose acetate-based resins such as triacetyl cellulose and polyethylene glycol; polyethylene terephthalate, polyethylene isophthalate, and polybutylene terephthalate. Ester-like polyester resin; poly (a (meth) methacrylate, poly(meth) acrylate-like (meth)acrylic resin; polycarbonate resin; polyether oxime resin; polyfluorene resin; polyimine resin; Polypropylene-based polyolefin resin; polynorbornene resin. Among them, a resin film formed of a cellulose resin, a polyester resin, a (meth)acrylic resin, a polycarbonate resin, and a polyolefin resin is preferable. Here, the (meth) acrylate type may be any of methacrylate or acrylate, and the term "(meth)" when referring to (meth)acrylic acid or the like is also the same.

As the thermoplastic resin film, a commercially available product can be used. For example, a commercially available product of a cellulose resin film may be, for example, "Fujitac (registered trademark) TD80", "Fujitac (registered trademark) TD80UF", and "Fujitac" (registered by Fuji FILM Co., Ltd.). Trademark) TD80UZ"; "KC2UAW", "KC8UX2M" and "KC8UY" manufactured by KONICA MINOLTA.

A commercially available product can be used as the polyester resin film. For example, a commercially available product of a polyester resin film may be, for example, "Diafoil (registered trademark)" manufactured by Mitsubishi Plastics Co., Ltd., and "Lumirror" (registered by Toray Co., Ltd.). "Cosmoshine (registered trademark)" manufactured by Toyobo Co., Ltd., etc.

As the (meth)acrylic resin film, a commercially available product can be used. For example, a commercially available product of a (meth)acrylic resin film may be, for example, "Technolloy (registered trademark)" by Sumitomo Chemical Co., Ltd., and "Acryplen" (registered by Mitsubishi Rayon Co., Ltd.). Trademarks) and so on.

A commercially available product can be used as the polycarbonate resin film. Lift For example, the "Panlite (registered trademark)" manufactured by Teijin Chemicals Co., Ltd. can be used as an example of a commercially available product of the polycarbonate resin film.

Examples of commercial products of polyolefin resin are Topas Advanced Polymers GmbH, "Topas" sold by Polyplastics, "ARTON" (registered trademark) sold by JSR (shares), and Zeon (Japan) "APEL" (registered trademark) and "APEL" (registered trademark) sold by Mitsui Chemicals Co., Ltd. (all of which are trade names), etc., which can be sold by such products. Make a film. In addition, a polyolefin resin film can be used, for example, "ARTON film" sold by JSR ("ARTON" is a registered trademark of the company), and "ESSINA" (registered trademark) sold by Sekisui Chemical Industry Co., Ltd. ) "Zeonor Film" (registered trademark) sold by Zeon (Japan).

The thickness of the thermoplastic resin film is usually from 5 to 100 μm, preferably from 10 to 50 μm.

(reflective polarizing film)

The reflective polarizing film may be a multilayer polarizing film having two or more layers of a refractive index difference or two or more types of materials, and a vapor deposited multilayer film having a refractive index different from that used in a spectroscope or the like. A two-layer or more birefringent layer multilayer film laminate formed of two or more kinds of materials having birefringence is formed by extending a resin laminate of two or more layers of a resin having two or more kinds of birefringence, and linearly polarizing The direction of the orthogonal axis is separated by reflection/transmission.

A reflective polarizing film can be used, for example, as a polyethylene naphthalate A diester, polyethylene terephthalate or polycarbonate is a material which is represented by elongation by a phase difference, and an acrylic resin represented by polymethyl methacrylate, which is made of JSR. "ARTON" (registered trademark) is a resin obtained by stretching a resin having a small amount of phase difference such as a decene-based resin. Specific examples of the reflective polarizing film include "DBEF" (registered trademark), "APF-V3" (product name), and "APF-V2" (product name) manufactured by 3M Company. The thickness of the reflective polarizing film is usually from 5 to 100 μm, preferably from 10 to 50 μm.

(reflective type polarizing film / laminate of thermoplastic resin film)

The laminate of the reflective polarizing film and the thermoplastic resin film may be a laminate of the films by, for example, an adhesive or an adhesive. Adhesives or adhesives may be selected as appropriate. From the viewpoints of the simplicity of the work and the prevention of the occurrence of optical strain, it is preferred to use an adhesive. As the adhesive, for example, an acrylic polymer, a polyoxymethylene polymer, a polyester, a polyurethane, a polyether or the like can be used as the matrix polymer. Among them, it is preferable to use an acrylic adhesive as an acrylic adhesive, and it is excellent in optical transparency, maintains moderate wettability and cohesive force, and is excellent in adhesion to a reflective polarizing film and a thermoplastic resin film, and further has good heat resistance. Sex, in the high temperature environment, there will be no peeling problems such as lifting and peeling.

The adhesive layer formed of the adhesive may optionally contain fine particles for displaying light scattering properties, and may also contain glass fibers, glass beads, resin beads, metal powder or other inorganic powder-like fillers, pigments, and coloring agents. Materials, antioxidants, UV absorbers, etc. UV absorber An acid ester compound, a diphenylketone type compound, a benzotriazole type compound, a cyanoacrylate type compound, a nickel salt fault type compound, etc.

The first protective film 3 may be a hard coat layer provided on the surface opposite to the bonding surface of the polarizing film. Thereby, it is possible to prevent scratches and the like which occur when the polarizing plate is processed. When the hard coat layer is provided, the thickness of the hard coat layer is preferably from 1 to 8 μm, more preferably from 1 to 6 μm, from the viewpoint of both protection and flexibility. When the thickness of the hard coat layer exceeds 8 μm, the flexibility is lowered, and cracking tends to be easily introduced during flexing. On the other hand, when the thickness of the hard coat layer is less than 1 μm, although the flexibility is good, there is a tendency that sufficient characteristics are not obtained from the viewpoint of in-plane uniformity.

The hard coat layer may be formed of a resin film layer. The resin material forming the resin coating layer can be used without any particular limitation as long as the film after the formation of the resin coating layer has sufficient strength and transparency. Examples of the resin include an active energy ray-curable resin such as a thermosetting resin, a thermoplastic resin, an ultraviolet curable resin, and an electron beam curable resin, and a two-liquid mixed resin.

In addition, the ultraviolet curable resin can cure the resin by irradiation with ultraviolet rays, and the resin film layer can be efficiently formed by a simple processing operation, and a light diffusion layer such as an antiglare layer can be formed. More suitable. Examples of the ultraviolet curable resin include various types such as polyester-based, acrylic-based, urethane-based, guanamine-based, polyfluorene-based, and epoxy-based resins, and include ultraviolet curable monomers, oligomers, and polymers. The ultraviolet curable resin to be preferably used is, for example, a functional group having ultraviolet polymerizability, and includes two or more, particularly, 3 to 6 such functional groups. Acrylic monomer or oligomer component. Further, an ultraviolet polymerization initiator is blended in the ultraviolet curable resin.

A method of forming the resin coating layer can be carried out by a suitable known method. For example, there is a method in which the above-mentioned resin (coating liquid) is applied to the first protective film 3 and dried. When a curable resin is used, it is hardened after drying. The coating method of the coating liquid may be a method such as fountain molding, die coating, casting, spin coating, fountain metal plating, or gravure. Further, at the time of application, the coating liquid may be diluted with a general solvent such as toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, isopropyl alcohol or ethanol, or may be directly applied without dilution.

The polarizing plate 10 of the present invention is formed on at least one side surface of the absorbing polarizing film 1, and the first protective film 3 is laminated thereon. The first protective film 3 is formed on the opposite side to the surface on which the absorbing polarizing film 1 is laminated. It is important that the Vickers hardness of the surface is 10 kgf/mm ² or more. When the Vickers hardness is 10 kgf/mm ² or more, when the polarizing plate is applied to a liquid crystal display device, transfer of the polarizing plate 10 can be prevented. In addition, as long as the Vickers hardness of the surface of the first protective film 3 on the opposite side to the surface on which the absorption-type polarizing film 1 is laminated is 10 kgf/mm ² or more, it can be applied to a liquid crystal display device. The Vickers hardness is preferably 30 kgf/mm ² or less.

<Second protective film>

The second protective film 5 may be the same as the above-described thermoplastic resin film. When the first protective film 3 is a thermoplastic resin film, the second protective film 5 and the first protective film 3 may be the same or different.

<Polarizer>

The polarizing plate 10 is a laminate in which the absorption-type polarizing film 1 and the first protective film 3 are laminated. As a method of laminating an absorbing polarizing film and a protective film, a method of laminating the films by an adhesive or an adhesive is usually employed. When the two-layer protective film of the absorbing polarizing film is used, the same kind of adhesive or adhesive may be used, or different kinds of adhesives or adhesives may be used.

Examples of the subsequent agent include a water-based adhesive, a photocurable adhesive, and the like. The aqueous adhesive agent can make the adhesive layer thinner by dissolving the adhesive component in water or dispersing the adhesive component in water. As a water-based adhesive, for example, a main component of the adhesive (composition) is a polyvinyl alcohol-based resin or an amine-ester resin, and a preferred adhesive is exemplified.

In addition to partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, the polyvinyl alcohol-based resin may also be a carboxy-modified polyvinyl alcohol, an acetoacetyl-modified polyvinyl alcohol, or a hydroxymethyl-modified polyethylene. A modified polyvinyl alcohol-based resin such as an alcohol or an amine-modified polyvinyl alcohol. When a polyvinyl alcohol-based resin is used as the binder component, the binder is often prepared as an aqueous solution of a polyvinyl alcohol-based resin. The concentration of the polyvinyl alcohol-based resin in the adhesive is usually from about 1 to 10 parts by weight, preferably from 1 to 5 parts by weight, per 100 parts by weight of the water.

In order to improve the adhesion, it is preferable to add a curable component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to the adhesive containing a polyvinyl alcohol-based resin as a main component. The water-soluble epoxy resin may, for example, be a polyalkylene polyamine such as di-ethyltriamine or tri-extension ethyltetraamine, and adipic acid. The polyamine polyamine obtained by the reaction of the dicarboxylic acid is a polyamidamine polyamine epoxy resin obtained by reacting epichlorohydrin with it. "Sumirez Resin (registered trademark) 650 (30)" and "Sumirez Resin (registered trademark) 675", which are sold under the trade name of the Polyamide Polyamine Epoxy Resin, respectively, by Tamoka Chemical Industry Co., Ltd. , "WS-525", etc. sold by Starlight PMC (shares), etc., which can be suitably used. The curable component or the crosslinking agent is usually added in an amount of from 1 to 100 parts by weight, preferably from 1 to 50 parts by weight, per 100 parts by weight of the polyvinyl alcohol-based resin. When the amount of addition is small, the effect of improving the adhesion is small. On the other hand, when the amount of addition is large, the adhesive layer tends to be embrittled.

The layered body joined by the water-based adhesive is usually subjected to a drying treatment to dry and harden the adhesive layer. The drying treatment can be carried out by, for example, hot air blowing.

The drying temperature is suitably selected from the range of about 40 to 100 ° C, preferably 60 to 100 ° C. The drying time is, for example, about 20 to 1,200 seconds. The thickness of the adhesive layer after drying is usually about 0.001 to 5 μm, preferably 0.01 μm or more, more preferably 2 μm or less, still more preferably 1 μm or less. When the thickness of the layer is too large, the polarizing plate tends to be inferior in appearance.

After the drying treatment, the curing may be carried out at a temperature above room temperature for at least half a day, usually for more than one day, to obtain sufficient bonding strength. This aging is typically carried out in a state of being wound into a roll. The preferred curing temperature is in the range of 30 to 50 ° C, more preferably 35 ° C or more and 45 ° C or less. When the aging temperature exceeds 50 ° C, the so-called "winding over-tightening" easily occurs in the state of the roll. In addition, the humidity at the time of ripening is, for example, preferably to make it relatively wet. A method in which the degree becomes 70% or less is suitable. The aging time is usually about 1 to 10 days, preferably about 2 to 7 days.

The photocurable adhesive agent may, for example, be a mixture of a photocurable epoxy resin and a photocationic polymerization initiator. Examples of the photocurable epoxy resin include an alicyclic epoxy resin, an epoxy resin having no alicyclic structure, and the like.

Further, the photocurable adhesive can be used by adding a radical polymerization type initiator and/or a cationic polymerization type to an epoxy resin, an acrylic resin, an oxetane resin, an amine ester resin, a polyvinyl alcohol resin or the like. Agent.

After laminating, the photocurable adhesive is cured by irradiation of an active energy ray after lamination by a photocurable adhesive. The light source of the active energy ray is, for example, preferably an active energy ray having a luminescent distribution at a wavelength of 400 nm or less. Specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a chemical lamp, a black light lamp are preferably used. , microwave excited mercury lamps, metal halide lamps, etc. The light irradiation intensity of the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive, and is not particularly limited, but the irradiation intensity in the wavelength region effective for activation of the polymerization initiator is preferably 0.1. Up to 6,000 mW/cm ² . When the irradiation intensity is 0.1 mW/cm ² or more, the reaction time does not become too long, and when it is 6,000 mW/cm ² or less, heat generated by the light source and heat generated by curing of the photocurable adhesive occur. The yellowing of the epoxy resin and the possibility of deterioration of the polarizing plate are less.

The light irradiation time of the photocurable adhesive is controlled one by one with the cured photocurable adhesive, but it is preferable that the cumulative light amount represented by the product of the irradiation intensity and the irradiation time is 10 to 10,000. mJ/cm ² mode setting. When the cumulative light amount of the photocurable adhesive is 10 mJ/cm ² or more, a sufficient amount of the active species derived from the polymerization initiator can be generated to make the curing reaction more sure, and when it is 10,000 mJ/cm ² or less, the irradiation is performed. Time does not become too long and can maintain good productivity. Further, the thickness of the adhesive layer after the active energy ray irradiation is usually about 0.001 to 5 μm, preferably 0.01 μm or more, more preferably 2 μm or less, still more preferably 1 μm or less.

When the photocurable adhesive is cured by irradiation with an active energy ray, the functions of the polarizing plate such as the degree of polarization of the polarizing film, the transmittance, the hue, and the transparency of the transparent film such as a protective film are preferably not reduced. Hardening under the conditions.

As a method of laminating an absorbing polarizing film and a protective film, a method of laminating with an adhesive is also employed. As the adhesive, for example, an acrylic polymer, a polyoxymethylene polymer, a polyester, a polyurethane, a polyether or the like can be used as the matrix polymer. Further, among the matrix polymers, a crosslinking agent such as a polyisocyanate compound, a decane coupling agent, an antistatic agent such as an ionic compound, or the like may be added.

<Polarizer with Adhesive>

The polarizing plate with an adhesive is provided with an adhesive layer on one side of the protective film constituting the polarizing plate. As shown in Fig. 1, the polarizing plate 20 with an adhesive according to the present invention has only the first transparent protective film 3 laminated on the absorbing polarizing film. When the single side of the film 1 is provided, an adhesive layer 15 may be provided on the surface of the absorbing polarizing film 1, and the first transparent protective film 3 may be laminated on one side of the absorbing polarizing film 1 and on the other side. In the case of the second protective film 5, the adhesive layer 15 may be provided on the surface of the second protective film 5.

The adhesive forming the adhesive layer 15 may be any one of the properties (transparency, durability, rework, etc.) used for the optical film, for example, using an acrylic resin containing an acrylic resin and a crosslinking agent. The acrylic resin is an acrylic monomer having a (meth) acrylate as a main component and further containing a small amount of a (meth)acrylic monomer having a functional group in the presence of a polymerization initiator. The radical polymerization is carried out, and the glass transition temperature (Tg) is 0 ° C or less.

<Liquid crystal display device>

The above-mentioned polarizing plate 20 with an adhesive is suitable for use in a liquid crystal display device. Referring to Fig. 2, a liquid crystal display device 55 is provided with a liquid crystal panel, and a liquid crystal panel is provided, and a polarizing plate 20 with an adhesive is laminated on one side surface of the liquid crystal cell 30 through the adhesive layer, and the polarizing plate 25 transmits the same or different. The layer of adhesive is laminated on the other side. The liquid crystal cell may be any conventionally known mode such as an IPS mode, a VA mode, or a TN mode.

On the opposite side to the liquid crystal cell to which the polarizing plate 20 with the adhesive of the present invention is attached, the same type of polarizing plate or a known polarizing plate can be laminated. Further, the polarizing plate 20 with the adhesive is preferably disposed on the back side (backlight side) of the liquid crystal display device 55, and more preferably disposed so that the first protective film 3 is on the backlight side.

(Example)

Hereinafter, the invention is further illustrated by the series of examples, but the invention is not limited to the examples. In the examples, the % and the parts expressed by the content or the amount used are based on the weight basis unless otherwise specified.

[Example 1]

(A) Production of the first protective film

A film of an acrylic hard coat layer was laminated as a first protective film by using a triacetonitrile cellulose film (trade name "KC2UAW" manufactured by KONICA MINOLTA Co., Ltd.) having a thickness of 25 μm. In the first protective film, the surface of the triacetyl cellulose film in which the acrylic hard coat layer is not laminated is used as the surface of the laminated absorption type polarizing film.

In the first protective film, the surface opposite to the surface of the build-up absorption type polarizing film is used as a measurement surface, and according to the method of "Vickers hardness test-test method" of JIS Z 2244:2009, a microchip manufactured by Fischer Instruments Co., Ltd. is used. The Vickers hardness of the first protective film was measured by a small hardness meter HM2000. The measurement load applied to the measurement surface was 300 mN/10 s, and three points were measured, and the average value thereof was used as a measurement value. The results are shown in Table 1.

(B) Modulation of water-based adhesives

3 parts of carboxy-modified polyvinyl alcohol (from Kuraray Co., Ltd. under the trade name "KL-318") was added to 100 parts of water, and a water-soluble epoxy resin polyether amine epoxy additive was added to the aqueous solution. [taken from the name "Sumirez Resin (registered trademark) 650 (30)" of the Tiangang Chemical Industry Co., Ltd., A water-based adhesive was prepared by adding 1.5 parts of an aqueous solution having a solid concentration of 30%.

(C) Production of absorption type polarizing film

The polyvinyl alcohol film having an average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol% or more and a thickness of 75 μm was stretched about 5 times in a dry axis, further kept in a state of tension, and immersed in pure water at 60 ° C for 1 minute. The aqueous solution of iodine/potassium iodide/water in a weight ratio of 0.05/5/100 was immersed at 28 ° C for 60 seconds. Thereafter, the aqueous solution of potassium iodide/boric acid/water in a weight ratio of 8.5/8.5/100 was immersed at 72 ° C for 300 seconds. Subsequently, it was washed with pure water at 26 ° C for 20 seconds, and then dried at 65 ° C to prepare an absorption type polarizing film in which polyvinyl alcohol had an iodine adsorption alignment.

(D) Production of polarizing plate

The first protective film produced by the above (A) is laminated on one side of the absorbing polarizing film produced in the above (C), and the corona discharge is applied to one side. A cyclic olefin-based resin film having a thickness of 23 μm (trade name "Zeonor Film (registered trademark) ZF14" of Zeon Co., Ltd.) was passed through the corona discharge treatment area prepared by the water-based adhesive prepared in the above (B). A polarizing plate was formed on the other side of the absorbing polarizing film. The drying of the subsequent agent was carried out by drying the film at 80 ° C for 5 minutes after laminating the film. The obtained polarizing plate was allowed to stand at 40 ° C for 168 hours thereafter.

(Evaluation of transfer resistance)

First, as shown in FIG. 3, the light-diffusing sheet 60 (trade name "BEF" manufactured by 3M Company) and the aluminum plate 65 in which the polarizing plate 10 and the 稜鏡 pattern are arranged in an in-line manner are arranged in this order, and The first protective film of the polarizing plate 10 is superposed so as to become the side of the light diffusion sheet 60. Next, a load of 0.125 g/mm ^{2 was} applied from the side of the polarizing plate 10, and it was allowed to stand at 85 ° C for 24 hours. Thereafter, it was visually confirmed whether or not the trace of BEF was transferred to the polarizing plate. When the trace of BEF is not confirmed on the polarizing plate, it is marked as "○", and when the trace of BEF is confirmed, it is marked as "X".

[Example 2]

The first protective film is used for a film obtained by laminating an acrylic hard coat layer under the trade name "Advanced Polarized Film, Version 3 (APF-V3)" from 3M Company. Thereafter, a polarizing plate was produced in the same manner as in Example 1. The measurement of the Vickers hardness of the first protective film and the evaluation of the transfer resistance of the polarizing plate were carried out in the same manner as in Example 1.

[Example 3]

A polarizing plate was produced in the same manner as in Example 2 except that "Advanced Polarized Film, Version 3 (APF-V3)" which did not form a hard coat layer was used as the first protective film. The measurement of the Vickers hardness of the first protective film and the evaluation of the transfer resistance of the polarizing plate were carried out in the same manner as in Example 1.

[Example 4]

In addition to being the first protective film, use KONICA MINOLTA (shares) A polarizing plate was produced in the same manner as in Example 1 except that the product name "KC2UAW" and the laminate of "APF-V3" from 3M Company were used. The laminate of these films is an acrylic adhesive sheet having a thickness of 5 μm which is commercially available as an adhesive layer on "KC2UAW", and is further laminated with "APF-V3" through the adhesive layer, and "KC2UAW" is added. The side is laminated on the surface of the absorption type polarizing film. The measurement of the Vickers hardness of the first protective film and the evaluation of the transfer resistance of the polarizing plate were carried out in the same manner as in Example 1.

[Comparative Example 1]

A polarizing plate was produced in the same manner as in Example 4 except that the product name "Advanced Polarized Film, Version 2 (APF-V2)" was used as the first protective film. The measurement of the Vickers hardness of the first protective film and the evaluation of the transfer resistance of the polarizing plate were carried out in the same manner as in Example 1.

Claims (9)

A polarizing plate is attached to a single side surface of an absorbing polarizing film, and has a first protective film laminated thereon, wherein the first protective film has a Vickers hardness of 10 to 30 kgf/mm ² on a surface opposite to the absorbing polarizing film. The polarizing plate according to claim 1, wherein the first protective film is a thermoplastic resin film. The polarizing plate according to claim 1, wherein the first protective film is a reflective polarizing film. The polarizing plate according to claim 1, wherein the first protective film is a laminated body of a reflective polarizing film and a thermoplastic resin film. The polarizing plate according to any one of claims 1 to 4, wherein a Vickers hardness of the surface on the opposite side of the one-side area layer of the absorption-type polarizing film from the absorption-type polarizing film is 10 to 30 kgf/ The first protective film of mm ² has a second protective film on the area layer on the other side. A polarizing plate with an adhesive, which is formed with an adhesive layer on the side of the absorbing polarizing film of the polarizing plate according to any one of claims 1 to 4. A polarizing plate with an adhesive is formed with an adhesive layer on the second protective film side of the polarizing plate described in claim 5 of the patent application. A liquid crystal display device in which a polarizing plate with an adhesive as described in claim 6 or 7 is laminated on a liquid crystal cell. The liquid crystal display device according to claim 8, wherein the polarizing plate with the adhesive is laminated on the side of the light source of the liquid crystal cell with the adhesive layer side.