JP6898481B2 - Polarizing plate and display device - Google Patents

Description

The present invention relates to a polarizing plate and a display device including the polarizing plate.

Polarizing plates are widely used in display devices such as liquid crystal display devices, and in recent years, in various mobile devices such as smartphones and slate PCs. Generally, a polarizing plate has a structure in which a protective film is attached to one side or both sides of a polarizing plate using an adhesive, but with the development into mobile devices, the polarizing element and the protective film constituting the polarizing plate are thinned. There is an increasing demand.

As an adhesive used for bonding the polarizer and the protective film, a photocurable adhesive and an aqueous adhesive such as an aqueous polyvinyl alcohol solution are known, and Patent Documents 1 to 10 describe one of these or one of them. A polarizing plate in which protective films are bonded to both sides of a polarizer using both is described.

Japanese Unexamined Patent Publication No. 2013-228726 Japanese Unexamined Patent Publication No. 2013-210513 Japanese Unexamined Patent Publication No. 2012-144690 Japanese Unexamined Patent Publication No. 2012-203211 JP-A-2009-109994 Japanese Unexamined Patent Publication No. 2009-139585 Japanese Unexamined Patent Publication No. 2009-134121 Japanese Unexamined Patent Publication No. 2010-091603 JP-A-2010-091602 Japanese Unexamined Patent Publication No. 2008-170717

When the polarizing element and the protective film constituting the polarizing plate are thinned, the surface of the protective film bonded to the polarizing element via the adhesive layer is distorted in a minute region, and the surface is wavy and uneven. It has been clarified by the examination of the present inventor that this occurs. This surface unevenness does not directly adversely affect the optical characteristics of the polarizing plate, but the protective film is arranged on the outside (for example, the outermost surface) when the polarizing plate is attached to the display cell. In this case, the surface unevenness remains even after bonding, and the reflected image from the protective film surface is distorted and a glossy feeling cannot be obtained. Therefore, the surface uniformity (degree and period of waviness of the surface unevenness depending on the location) However, there are problems in appearance such as (the surface unevenness is not locally conspicuous) and lack of luxury.

Therefore, an object of the present invention is to provide a thin polarizing plate having a good appearance when attached to a display cell, and a display device using the same.

The present invention provides the following polarizing plates and display devices.
[1] Polarizer and
A first protective film laminated on one surface of the polarizer via a first adhesive layer having a thickness of less than 2.0 μm.
A second protective film laminated on the other surface of the polarizer via a second adhesive layer having a thickness of 2.0 μm or less.
It is a polarizing plate containing
The second protective film is a protective film that is arranged closer to the display cell than the first protective film when the polarizing plate is arranged on the display cell.
A polarizing plate in which the thickness of the first adhesive layer is smaller than the thickness of the second adhesive layer.

[2] The polarizing plate according to [1], wherein the first and second adhesive layers are a cured product layer of a photocurable adhesive.

[3] The polarizing plate according to [1] or [2], wherein the thickness of the first adhesive layer is 0.7 μm or less.

[4] The polarizing plate according to any one of [1] to [3], wherein the difference between the thickness of the second adhesive layer and the thickness of the first adhesive layer is 0.3 μm or more.

[5] The polarizing plate according to any one of [1] to [4], wherein the polarizing element has a thickness of 10 μm or less.

[6] The polarizing plate according to any one of [1] to [5], further comprising an adhesive layer for bonding to the display cell, which is laminated on the outer surface of the second protective film.

[7] A display device including the display cell and the polarizing plate according to any one of [1] to [6] arranged on at least one surface thereof.

According to the present invention, it is possible to provide a polarizing plate in which the above-mentioned unevenness on the surface of the first protective film and the resulting distortion of the reflected image are suppressed. When such a polarizing plate is arranged on the display cell so that the first protective film is on the outside (the second protective film is on the display cell side), the distortion of the reflected image from the surface of the first protective film is distorted. Is suppressed, so the appearance is excellent.

It is a schematic cross-sectional view which shows an example of the layer structure of the polarizing plate which concerns on this invention. It is a schematic cross-sectional view which shows the state when the polarizing plate shown in FIG. 1 is arranged on the display cell. It is schematic cross-sectional view which shows an example of the layer structure of the liquid crystal display apparatus which includes a display cell (liquid crystal cell), and the polarizing plate (polarizing plate with a double-sided protective film) arranged on the front side and the rear side thereof. It is a flowchart which shows a preferable example of the manufacturing method of the polarizing plate which concerns on this invention. It is a schematic cross-sectional view which shows an example of the layer structure of the laminated film obtained in the resin layer forming step. It is a schematic cross-sectional view which shows an example of the layer structure of the stretch film obtained in the stretching step. It is a schematic cross-sectional view which shows an example of the layer structure of the polarizing laminated film obtained in the dyeing process. It is schematic cross-sectional view which shows an example of the layer structure of the bonding film obtained in the 1st bonding step. It is schematic cross-sectional view which shows an example of the layer structure of the polarizing plate with a single-sided protective film obtained in a peeling step.

<Polarizer>
FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the polarizing plate according to the present invention. Further, FIG. 2 is a schematic cross-sectional view showing a state when the polarizing plate shown in FIG. 1 is arranged on the display cell. Like the polarizing plate 1 shown in FIG. 1, the polarizing plate of the present invention includes a polarizing element 5, a first protective film 10 laminated on one surface thereof via a first adhesive layer 15, and the other. A second protective film 20 laminated on the surface via the second adhesive layer 25 is provided.

As shown in FIG. 2, the first protective film 10 is a protective film that is arranged outside the second protective film 20 when the polarizing plate 1 is arranged on the display cell 50, and the polarizing plate 1 is arranged. A protective film that typically forms the outermost surface when placed on the display cell 50. The second protective film 20 is a protective film arranged on the display cell 50 side of the first protective film 10. The polarizing plate 1 can be arranged and bonded on the display cell 50 by using the adhesive layer 60 provided on the outer surface of the second protective film 20 arranged on the display cell 50 side.

(1) Thickness of Adhesive Layer In the present invention, the first protective film 10 and the polarizer 5 that form an outer surface (typically the outermost surface) when the polarizing plate 1 is arranged on the display cell 50. _{The thickness T 1} of the first adhesive layer 15 _{interposed between them is the thickness T 2 of} the second adhesive layer 25 interposed between the second protective film 20 arranged on the display cell 50 side and the polarizer 5. Make it smaller than. That is, the thickness T ₁ of the first adhesive layer 15 is relatively small, while the thickness T ₂ of the second adhesive layer 25 is relatively large.

By making the thickness T ₁ of the first adhesive layer 15 relatively small, the shrinkage force when the adhesive forming the first adhesive layer 15 is cured or dried can be reduced, so that the first protective film Even if the thickness of the 10 and the polarizer 5 is reduced, it is possible to prevent the first protective film 10 and the polarizer 5 from being defeated by the shrinking force of the adhesive and causing irregularities on the surface of the first protective film 10. it can. When the thickness of the polarizer 5 is 10 μm or less, the appearance deterioration due to the occurrence of surface unevenness is particularly remarkable. Even in such a case, according to the present invention, the surface unevenness of the first protective film 10 is generated. To provide a polarizing plate which can suppress the distortion of the reflected image due to the distortion, obtain a clear reflected image, have an excellent glossiness on the surface of the first protective film 10, and have surface uniformity and a high-class feeling. Can be done.

_{Specifically, the thickness T 1} of the first adhesive layer 15 is set to less than 2.0 μm, preferably 1.0 μm or less. _{When the thickness of the polarizer 5 is 10 μm or less, the thickness T 1} of the first adhesive layer 15 is 0.7 μm or less in order to sufficiently suppress the shrinkage force of the adhesive and suppress the occurrence of surface irregularities. It is more preferably 0.4 μm or less.

_{The thickness T 1} of the first adhesive layer 15 is usually 0.01 μm or more, preferably 0.05 μm or more. If the thickness T ₁ is less than 0.01 μm, sufficient adhesive strength may not be obtained.

As described above, in the present invention, the first aspect that can affect the appearance when the polarizing plate 1 is arranged on the display cell 50, that is, can be visually recognized in the state where the polarizing plate 1 is arranged on the display cell 50. _{While the thickness T 1} of the first adhesive layer 15 responsible for adhering the protective film 10 is relatively small, the polarizing plate 1 is arranged on the display cell 50 on the surface of the second protective film 20. Since it is not visible in the state and therefore, even if surface irregularities occur, the appearance is hardly adversely affected, it is not necessary to make _{the thickness T 2 of the second adhesive layer 25, which is responsible for adhering the second protective film 20, relatively small.} Rather, it is important to make it relatively large for the following reasons.

That is, if the thickness of the adhesive layer is made too small, a problem is likely to occur in which minute bubbles are mixed in the adhesive layer when the protective film and the polarizer are bonded to each other. Although such bubbles cannot be visually observed by themselves, when a polarizing plate is incorporated in a display device such as a liquid crystal display device and the display device is turned on, light scattering occurs due to the dense bubbles, and the display state is black. Light leaks (bubbles become bright spots), causing display problems.

Then, such light leakage due to air bubbles tends to be a problem in the second adhesive layer 25 interposed between the second protective film 20 arranged on the display cell 50 side and the polarizer 5, and is arranged on the outside. The first adhesive layer 15 interposed between the first protective film 10 and the polarizer 5 is less likely to cause a problem. This is the first with reference to FIG. 3, which shows a liquid crystal display device including a display cell (liquid crystal cell) 50 and a polarizing plate 1 arranged on the front side (visual side) and the rear side (backlight side) thereof. This is because the 2 adhesive layer 25 is arranged in the cross Nicol formed between the polarizing element 5 on the front side and the polarizer 5 on the rear side. When light scattering occurs in the cross Nicol, the black display collapses and light leakage occurs. _{Therefore, the thickness T 2} of the second adhesive layer 25, which does not easily affect the appearance when the polarizing plate 1 is arranged on the display cell 50, may be made larger than _{the thickness T 1} of the first adhesive layer 15. It is essential, and this makes it possible to suppress light leakage in the black display state.

On the other hand, since the first adhesive layer 15 is arranged outside the cloth Nicol, its thickness T ₁ is made relatively small, so that even if bubbles are generated, the problem of light leakage is unlikely to occur.

_{Specifically, the thickness T 2} of the second adhesive layer 25 is set to 2.0 μm or less, and is preferably 1.8 μm or less from the viewpoint of thinning the polarizing plate 1. If the thickness T ₂ exceeds 2.0 μm, it is disadvantageous for thinning the polarizing plate 1. The lower limit of the thickness T ₂ is not particularly limited as long as it is larger than _{the thickness T 1 of} the first adhesive layer 15, _{but from the viewpoint of adhesiveness, the thickness T 2} is usually 0.01 μm or more, preferably 0. It is 05 μm or more.

In order to effectively suppress unevenness on the surface of the first protective film 10 and effectively suppress light leakage in the black display state, the thickness T _{2 of} the second adhesive layer 25 and the thickness T 2 of the first adhesive layer 15 The difference from the thickness T ₁ is preferably 0.3 μm or more, more preferably 0.5 μm or more, and further preferably 0.9 μm or more.

(2) Adhesive for Forming Adhesive Layer As the adhesive for forming the first and second adhesive layers 15 and 25, a photocurable adhesive or a water-based adhesive can be used. As described above, one of the factors that cause unevenness on the surface of the first protective film 10 is the shrinkage force when the adhesive is cured or dried, and the adhesive layer is cured in a short time by light irradiation. The shrinkage force (per unit time) when using a photocurable adhesive that is bonded by letting it adhere is generally over a relatively long period of time by drying the solvent (water) by heating and then curing it if necessary. Since it is larger than the water-based adhesive, the present invention can be applied particularly preferably when the first adhesive layer 15 is formed from a photocurable adhesive, and the obtained unevenness suppressing effect is high.

The adhesive forming the first adhesive layer 15 and the adhesive forming the second adhesive layer 25 may be of the same type or different types, but for the above reason, the first adhesive layer The adhesive forming 15 is preferably a photocurable adhesive. The adhesive forming the second adhesive layer 25 is also preferably a photocurable adhesive. The photocurable adhesive can be 1) prepared as a solvent-free adhesive, thus eliminating the need for a drying step, and 2) can be used for bonding a protective film having low moisture permeability. There is also an advantage that there are many types of protective films that can be bonded compared to water-based adhesives.

The first and second adhesive layers 15 and 25 formed from the photocurable adhesive are cured product layers of the photocurable adhesive.

The photocurable adhesive refers to an adhesive that is cured by irradiating it with active energy rays such as ultraviolet rays, and includes, for example, a polymerizable compound and a photopolymerization initiator, a photoreactive resin, and a binder. Examples thereof include those containing a resin and a photoreactive cross-linking agent. Examples of the polymerizable compound include a photocurable epoxy compound; a photocurable vinyl compound such as a photocurable acrylic compound; and a photocurable urethane compound. Examples of the photopolymerization initiator include a photocationic polymerization initiator (for example, when a photocurable epoxy compound is used) and a photoradical polymerization initiator (for example, when a photocurable acrylic compound is used). ..

Examples of the water-based adhesive include an adhesive composed of a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. Of these, a water-based adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin is preferably used.

Examples of the polyvinyl alcohol-based resin include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and co-polymers of vinyl acetate and other monomers copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by saponifying the polymer, or a modified polyvinyl alcohol-based polymer in which the hydroxyl groups thereof are partially modified can be used. The water-based adhesive can contain additives such as polyhydric aldehyde, water-soluble epoxy compound, melamine-based compound, zirconia compound, and zinc compound.

(3) Polarizer The polarizing element 5 can be a uniaxially stretched polyvinyl alcohol-based resin layer in which a dichroic dye is adsorbed and oriented. The thickness of the polarizer 5 is preferably 10 μm or less, more preferably 7 μm or less. Making the thickness of the polarizer 5 10 μm or less is advantageous for thinning the polarizing plate 1. On the other hand, according to the present invention, even when the polarizing element 5 of such a thin film is used, the first protective film is used. 10 Unevenness on the surface can be effectively suppressed.

As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin layer, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

A film formed of such a polyvinyl alcohol-based resin constitutes the polarizer 5. The method for forming the film of the polyvinyl alcohol-based resin is not particularly limited, and the film can be formed by a known method, but the polyvinyl alcohol-based resin can be easily obtained from the viewpoint of obtaining a polarizer 5 having a thickness of 10 μm or less. It is preferable to apply the solution on the base film to form a film.

The polarizer 5 needs to be stretched and oriented, and is preferably stretched at a stretching ratio of more than 5 times, more preferably more than 5 times, and 17 times or less.

The degree of saponification of the polyvinyl alcohol-based resin can be in the range of 80.0 to 100.0 mol%, but is preferably in the range of 90.0 to 99.5 mol%, more preferably 94.0. It is in the range of ~ 99.0 mol%. When the degree of saponification is less than 80.0 mol%, the water resistance and moisture heat resistance of the obtained polarizing plate 1 are lowered. When a polyvinyl alcohol-based resin having a saponification degree of more than 99.5 mol% is used, the dyeing rate becomes slow, the productivity is lowered, and the polarizer 5 having sufficient polarization performance may not be obtained.

The degree of saponification is the unit ratio (mol%) of the rate at which the _{acetic acid group (acetoxy group: -OCOCH 3} ) contained in the polyvinyl acetate resin, which is the raw material of the polyvinyl alcohol resin, is changed to a hydroxyl group by the saponification process. It is expressed by the following formula:
Degree of saponification (mol%) = 100 x (number of hydroxyl groups) ÷ (number of hydroxyl groups + number of acetic acid groups)
Defined in. The degree of saponification can be determined in accordance with JIS K 6726 (1994). The higher the saponification degree, the higher the proportion of hydroxyl groups, and therefore the lower the proportion of acetic acid groups that inhibit crystallization.

The polyvinyl alcohol-based resin may be a partially modified polyvinyl alcohol. For example, polyvinyl alcohol-based resins modified with olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; alkyl esters of unsaturated carboxylic acids, acrylamide and the like can be mentioned. The rate of denaturation is preferably less than 30 mol%, more preferably less than 10%. When the modification exceeds 30 mol%, it becomes difficult to adsorb the dichroic dye, and the polarizer 5 having sufficient polarization performance cannot be obtained.

The average degree of polymerization of the polyvinyl alcohol-based resin is preferably 100 to 10000, more preferably 1500 to 8000, and further preferably 2000 to 5000. The average degree of polymerization of the polyvinyl alcohol-based resin can also be determined in accordance with JIS K 6726 (1994).

Examples of commercially available polyvinyl alcohol-based resins preferably used in the present invention are all trade names such as "PVA124" (saponification degree: 98.0-99.0 mol%) manufactured by Kuraray Co., Ltd. "PVA117" (saponification degree: 98.0-99.0 mol%), "PVA624" (saponification degree: 95.0-96.0 mol%), "PVA617" (saponification degree: 94.5 to 95) .5 mol%); "AH-26" (saponification degree: 97.0-98.8 mol%), "AH-22" (saponification degree: 97.5-) manufactured by Nippon Synthetic Chemical Industry Co., Ltd. 98.5 mol%), "NH-18" (saponification degree: 98.0-99.0 mol%), "N-300" (saponification degree: 98.0-99.0 mol%); Japan "JC-33" (saponification degree: 99.0 mol% or more), "JM-33" (saponification degree: 93.5-95.5 mol%), "JM-" of Vinegar Poval Co., Ltd. 26 ”(saponification degree: 95.5-97.5 mol%),“ JP-45 ”(saponification degree: 86.5-89.5 mol%),“ JF-17 ”(saponification degree: 98) .0-99.0 mol%), "JF-17L" (saponification degree: 98.0-99.0 mol%), "JF-20" (saponification degree: 98.0-99.0 mol%) )including.

The dichroic dye contained (adsorption orientation) in the polarizer 5 can be iodine or a dichroic organic dye. Specific examples of the bicolor organic dyes are Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Supra Blue G, Supra Blue GL, Supra Orange GL, Direct Includes Sky Blue, Direct First Orange S, and First Black. As the dichroic dye, only one kind may be used alone, or two or more kinds may be used in combination.

(4) First and Second Protective Films The first and second protective films 10 and 20, respectively, are thermoplastic resins such as chain polyolefin resins (polypropylene resins and the like) and cyclic polyolefin resins (norbornene resins and the like). ); Polyethylene resin such as cellulose triacetate, cellulose diacetate; polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate; polycarbonate resin; (meth) acrylic resin; Alternatively, it can be a transparent resin film made of a mixture thereof, a copolymer or the like. The first protective film 10 and the second protective film 20 may be the same type of protective film or different types of protective films.

Cyclic polyolefin resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described in, for example, JP-A 1-2240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin is mentioned. Specific examples of the cyclic polyolefin resin include an open (co) polymer of a cyclic olefin, an addition polymer of a cyclic olefin, and a copolymer of a cyclic olefin and a chain olefin such as ethylene and propylene (typically). Is a random copolymer), a graft polymer obtained by modifying these with an unsaturated carboxylic acid or a derivative thereof, and a hydride thereof. Of these, a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer is preferably used as the cyclic olefin.

Various products of cyclic polyolefin resins are commercially available. Examples of commercially available cyclic polyolefin resins are all trade names such as "Topas" (manufactured by Topas Advanced Polymers GmbH, available from Polyplastics Corporation), "Arton" (manufactured by JSR Corporation), Includes "ZEONOR" (manufactured by ZEON Corporation), "ZEONEX" (manufactured by ZEON Corporation), and "APEL" (manufactured by Mitsui Chemicals, Inc.).

In addition, all of them are trade names such as "Scina" (manufactured by Sekisui Chemical Co., Ltd.), "SCA40" (manufactured by Sekisui Chemical Co., Ltd.), and "Zeonoa Film" (manufactured by Zeon Corporation). A commercially available product of the filmed cyclic polyolefin resin film may be used as the protective film.

Cellulose ester-based resins are esters of cellulose and fatty acids. Specific examples of the cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Further, these copolymers or those in which a part of the hydroxyl group is modified with another substituent can also be used. Among these, cellulose triacetate (triacetyl cellulose: TAC) is particularly preferable. Many products of cellulose triacetate are commercially available, which is advantageous in terms of availability and cost. Examples of commercially available cellulose triacetates are all trade names, "Fujitac TD80" (manufactured by FUJIFILM Corporation), "Fujitac TD80UF" (manufactured by FUJIFILM Corporation), "Fujitac TD80UZ" (manufactured by FUJIFILM Corporation). ), "Fujitac TD40UZ" (manufactured by FUJIFILM Corporation), "KC8UX2M" (manufactured by Konica Minolta Opto Co., Ltd.), "KC4UY" (manufactured by Konica Minolta Opto Co., Ltd.).

The first protective film 10 and / or the second protective film 20 may be a protective film having an optical function such as a retardation film and a brightness improving film. For example, a retardation film to which an arbitrary retardation value is given by stretching a transparent resin film made of the above material (uniaxial stretching, biaxial stretching, etc.) or forming a liquid crystal layer or the like on the film. Can be.

The surface of the first protective film 10 and / or the second protective film 20 opposite to the polarizer 5 is surface-treated such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer. A layer (coating layer) can also be formed. The method for forming the surface treatment layer on the surface of the protective film is not particularly limited, and a known method can be used.

The thicknesses of the first and second protective films 10 and 20 are preferably thin from the viewpoint of thinning the polarizing plate 1, but if they are too thin, the strength is lowered and the processability is inferior. Therefore, the thicknesses of the first and second protective films 10 and 20 are preferably 5 to 90 μm, more preferably 5 to 60 μm, and even more preferably 5 to 50 μm. According to the present invention, even if the thickness of the first protective film 10 is 50 μm or less, unevenness on the surface of the first protective film 10 can be effectively suppressed.

(5) Adhesive Layer As shown in FIG. 2, the polarizing plate 1 is attached to another member (for example, a display device) on the outer surface (the surface opposite to the polarizer 5) of the second protective film 20 in the polarizing plate 1. The pressure-sensitive adhesive layer 60 for bonding to the display cell 50) may be laminated. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 60 is usually based on a (meth) acrylic resin, a styrene-based resin, a silicone-based resin, or the like, and a cross-linking agent such as an isocyanate compound, an epoxy compound, or an aziridine compound is added thereto. It consists of a pressure-sensitive adhesive composition. Further, it can be used as a pressure-sensitive adhesive layer containing fine particles and exhibiting light scattering properties.

The thickness of the pressure-sensitive adhesive layer 60 can be 1 to 40 μm, but it is preferably formed thin as long as the characteristics of processability and durability are not impaired, and specifically, it is preferably 3 to 25 μm. A thickness of 3 to 25 μm has good workability and is also suitable for suppressing a dimensional change of the polarizer 5. If the pressure-sensitive adhesive layer 60 is less than 1 μm, the adhesiveness is lowered, and if it exceeds 40 μm, problems such as the pressure-sensitive adhesive sticking out are likely to occur.

The method for forming the pressure-sensitive adhesive layer 60 is not particularly limited, and a pressure-sensitive adhesive composition (adhesive solution) containing each component including the above-mentioned base polymer is applied to the surface of the second protective film 20. The pressure-sensitive adhesive layer 60 may be formed on the separator (release film) in the same manner, and then the pressure-sensitive adhesive layer 60 may be transferred to the second protective film 20. When the pressure-sensitive adhesive layer 60 is formed on the surface of the second protective film 20, the surface of the second protective film 20 or the surface of the pressure-sensitive adhesive layer 60 may be subjected to surface treatment, for example, corona treatment, if necessary. ..

(6) Optical Layer The polarizing plate 1 can further include another optical layer laminated on the first protective film 10 or the second protective film 20. Other optical layers include a reflective polarizing film that transmits certain types of polarized light and reflects polarized light that exhibits the opposite properties; a film with an antiglare function that has an uneven surface on the surface; a film with a surface antireflection function. A reflective film having a reflective function on the surface; a transflective reflective film having both a reflective function and a transmissive function; a viewing angle compensating film and the like.

As a commercial product corresponding to a reflective polarizing film that transmits a certain kind of polarized light and reflects polarized light showing the opposite property, for example, "DBEF" (manufactured by 3M, Sumitomo 3M Ltd. in Japan) (Available), "APF" (manufactured by 3M, available from Sumitomo 3M Ltd. in Japan).

Examples of the viewing angle compensation film include an optical compensation film in which a liquid crystal compound is coated on the surface of a base material and is oriented and fixed, a retardation film made of a polycarbonate resin, a retardation film made of a cyclic polyolefin resin, and the like. ..

"WV film" (manufactured by FUJIFILM Corporation) and "NH film" (JX Nippon Oil) are commercially available products that correspond to optical compensation films in which a liquid crystal compound is applied to the surface of the substrate and oriented and fixed. Examples include (manufactured by Energy Co., Ltd.) and "NR film" (manufactured by JX Nippon Oil Energy Co., Ltd.).

Commercially available products equivalent to retardation films made of cyclic polyolefin resins include "Arton Film" (manufactured by JSR Corporation), "Scina" (manufactured by Sekisui Chemical Co., Ltd.), and "Zeonoa Film" (Zeon Corporation). Made by Co., Ltd.) and the like.

<Manufacturing method of polarizing plate>
The polarizing plate of the present invention can be suitably produced by, for example, the method shown in FIG. The method for producing the polarizing plate shown in FIG. 4 is described in the following step:
(1) Resin layer forming step S10 for forming a polyvinyl alcohol-based resin layer by applying a coating liquid containing a polyvinyl alcohol-based resin to at least one surface of the base film and then drying to obtain a laminated film. ,
(2) Stretching step S20, in which the laminated film is stretched to obtain a stretched film,
(3) Dyeing step S30, in which a polyvinyl alcohol-based resin layer of a stretched film is dyed with a dichroic dye to form a polarizer to obtain a polarizing laminated film.
(4) First bonding step S40, in which either the first or second protective film is bonded onto the polarizer of the polarizing laminated film via an adhesive layer to obtain a bonded film.
(5) Peeling step S50, in which the base film is peeled off from the bonded film to obtain a polarizing plate with a single-sided protective film.
(6) Second bonding step S60, in which the other protective film of the first and second protective films is bonded to the polarizing element surface of the polarizing plate with a single-sided protective film via an adhesive layer.
Is included in this order. Hereinafter, each step will be described with reference to FIGS. 5 to 9.

(1) Resin layer forming step S10
With reference to FIG. 5, this step is a step of forming a polyvinyl alcohol-based resin layer 6 on at least one surface of the base film 30 to obtain a laminated film 100. The polyvinyl alcohol-based resin layer 6 is a layer that becomes a polarizer 5 through the stretching step S20 and the dyeing step S30. The polyvinyl alcohol-based resin layer 6 can be formed by applying a coating liquid containing a polyvinyl alcohol-based resin to one side or both sides of the base film 30 and drying the coating layer. The method of forming the polyvinyl alcohol-based resin layer by such coating is advantageous in that it is easy to obtain the polarizer 5 of the thin film.

[Base film]
The base film 30 can be made of a thermoplastic resin, and more preferably it is made of a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, stretchability, and the like. Specific examples of such thermoplastic resins include polyolefin resins such as chain polyolefin resins and cyclic polyolefin resins (norbornen resins, etc.); polyester resins; (meth) acrylic resins; cellulose triacetates, Cellulosic ester-based resins such as cellulose diacetate; Polycarbonate-based resin; Polypolyalcohol-based resin; Polyvinyl acetate-based resin; Polyarylate-based resin; Polystyrene-based resin; Based resins; and mixtures and copolymers thereof.

The base film 30 may have a single-layer structure composed of one resin layer made of one or more kinds of thermoplastic resins, or a plurality of resin layers made of one kind or two or more kinds of thermoplastic resins. It may have a laminated multi-layer structure. The base film 30 is preferably composed of a resin that can be stretched at a stretching temperature suitable for stretching the polyvinyl alcohol-based resin layer 6 when the laminated film 100 is stretched in the stretching step S20 described later.

Examples of the chain polyolefin resin include homopolymers of chain olefins such as polyethylene resin and polypropylene resin, and copolymers composed of two or more kinds of chain olefins. The base film 30 made of a chain polyolefin resin is preferable because it can be stably stretched at a high magnification. Among them, the base film 30 is mainly composed of polypropylene resin (polypropylene resin which is a homopolymer of propylene or a copolymer mainly composed of propylene) and polyethylene resin (polyethylene resin which is a homopolymer of ethylene or ethylene). It is more preferable that it is made of a copolymer of

The propylene-based copolymer, which is one of the examples preferably used as the thermoplastic resin constituting the base film 30, is a copolymer of propylene and another monomer copolymerizable therewith.

Examples of other monomers copolymerizable with propylene include ethylene and α-olefin. As the α-olefin, an α-olefin having 4 or more carbon atoms is preferably used, and more preferably, an α-olefin having 4 to 10 carbon atoms. Specific examples of α-olefins having 4 to 10 carbon atoms include linear monoolefins such as 1-butene, 1-pentene, 1-hexene, 1-hexene, 1-octene, and 1-decene; Branched monoolefins such as −methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene; including vinylcyclohexane. The copolymer of propylene and another monomer copolymerizable therewith may be a random copolymer or a block copolymer.

The content of the other monomer is, for example, 0.1 to 20% by weight, preferably 0.5 to 10% by weight in the copolymer. The content of other monomers in the copolymer is determined by infrared (IR) spectrum measurement according to the method described on page 616 of the "Polymer Analysis Handbook" (published by Kinokuniya Bookstore, 1995). Can be sought.

Among the above, as the polypropylene-based resin, a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-1-butene random copolymer, or a propylene-ethylene-1-butene random copolymer is preferably used.

It is preferable that the three-dimensional regularity of the polypropylene-based resin is substantially isotactic or syndiotactic. The base film 30 made of a polypropylene-based resin having substantially isotactic or syndiotactic stereoregularity has relatively good handleability and excellent mechanical strength in a high temperature environment.

The polyester resin is a resin having an ester bond, and is generally composed of a polyvalent carboxylic acid or a derivative thereof and a polycondensate of a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylic acid. As the polyhydric alcohol, a divalent diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, cyclohexanedimethanol and the like.

A typical example of the polyester resin is polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol. Polyethylene terephthalate is a crystalline resin, but the one in a state before the crystallization treatment is easier to perform a treatment such as stretching. If necessary, the crystallization treatment can be carried out at the time of stretching or by heat treatment after stretching. Further, a copolymerized polyester having reduced crystallinity (or amorphous) by copolymerizing another kind of monomer with the skeleton of polyethylene teletarate is also preferably used. Examples of such resins include those obtained by copolymerizing cyclohexanedimethanol and isophthalic acid. These resins also have excellent stretchability and can be preferably used.

Specific examples of polyester resins other than polyethylene terephthalate and its copolymers include polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, and polycyclohexanedimethyl terephthalate. , Polycyclohexanedimethylnaphthalate, and mixtures and copolymers thereof.

The (meth) acrylic resin is a resin containing a compound having a (meth) acryloyl group as a main constituent monomer. Specific examples of the (meth) acrylic resin include poly (meth) acrylic acid esters such as polymethyl methacrylate; methyl methacrylate- (meth) acrylic acid copolymers; methyl methacrylate- (meth) acrylic acid. Ester copolymer; methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (MS resin, etc.); methyl methacrylate and alicyclic hydrocarbon group It contains a copolymer with the compound (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) norbornyl copolymer, etc.). _{Preferably, a polymer containing poly (meth) acrylic acid C 1-6} alkyl ester as a main component, such as methyl poly (meth) acrylate, is used, and more preferably, methyl methacrylate as a main component (50 to 100) is used. A methyl methacrylate-based resin having a weight of% by weight, preferably 70 to 100% by weight) is used.

The polycarbonate-based resin is an engineering plastic made of a polymer in which monomer units are bonded via a carbonate group, and is a resin having high impact resistance, heat resistance, flame retardancy, and transparency. The polycarbonate-based resin constituting the base film 30 may be a resin called modified polycarbonate having a polymer skeleton modified in order to lower the photoelastic coefficient, a copolymerized polycarbonate having improved wavelength dependence, or the like.

Various products of polycarbonate-based resins are commercially available. Examples of commercially available polycarbonate resins are "Panlite" (manufactured by Teijin Chemicals Ltd.), "Iupilon" (manufactured by Mitsubishi Engineering Plastics Co., Ltd.), and "SD Polyca" (Sumitomo Dow). (Manufactured by Co., Ltd.), "Calibre" (manufactured by Dow Chemical Co., Ltd.), etc.

Among the above, polypropylene-based resins are preferably used from the viewpoint of stretchability, heat resistance, and the like.

Regarding the cyclic polyolefin resin and the cellulose ester resin that can be used for the base film 30, the matters described about the protective film are cited. Further, the chain polyolefin resin, the polyester resin, the (meth) acrylic resin, and the polycarbonate resin as described above in relation to the base film 30 can also be used as a constituent material of the protective film.

In addition to the above-mentioned thermoplastic resin, any suitable additive may be added to the base film 30. Examples of such additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants and the like. .. The content of the thermoplastic resin in the base film 30 is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. .. If the content of the thermoplastic resin in the base film 30 is less than 50% by weight, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

The thickness of the base film 30 can be appropriately determined, but in general, 1 to 500 μm is preferable, 1 to 300 μm is more preferable, and 5 to 200 μm is preferable, and 5 to 5 is generally preferable from the viewpoint of workability such as strength and handleability. Most preferably 150 μm.

[Coating liquid containing polyvinyl alcohol resin]
The coating liquid is preferably a polyvinyl alcohol-based resin solution obtained by dissolving a polyvinyl alcohol-based resin powder in a good solvent (for example, water). Details of the polyvinyl alcohol-based resin are as described above.

The coating liquid may contain additives such as a plasticizer and a surfactant, if necessary. As the plasticizer, a polyol or a condensate thereof or the like can be used, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol and polyethylene glycol. The blending amount of the additive is preferably 20% by weight or less of the polyvinyl alcohol-based resin.

[Coating of coating liquid and drying of coating layer]
The method of applying the coating liquid to the base film 30 is a wire bar coating method; a roll coating method such as reverse coating or gravure coating; a die coating method; a comma coating method; a lip coating method; a spin coating method; a screen coating. Method; Fountain coating method; Dipping method; Spray method and the like can be appropriately selected.

When the coating liquid is applied to both sides of the base film 30, it can be applied one side at a time by using the above method, or the base material can be applied by using a dipping method, a spray coating method or other special equipment. It is also possible to coat both sides of the film 30 at the same time.

The drying temperature and drying time of the coating layer (polyvinyl alcohol-based resin layer before drying) are set according to the type of solvent contained in the coating liquid. The drying temperature is, for example, 50 to 200 ° C, preferably 60 to 150 ° C. When the solvent contains water, the drying temperature is preferably 80 ° C. or higher. The drying time is, for example, 2 to 20 minutes.

The polyvinyl alcohol-based resin layer 6 may be formed on only one surface of the base film 30, or may be formed on both surfaces. When formed on both sides, curling of the film that may occur during the production of the polarizing laminated film 300 (see FIG. 7) can be suppressed, and two polarizing plates can be obtained from one polarizing laminated film 300, so that polarized light can be obtained. It is also advantageous in terms of plate production efficiency.

The thickness of the polyvinyl alcohol-based resin layer 6 in the laminated film 100 is preferably 3 to 30 μm, more preferably 5 to 20 μm. If the polyvinyl alcohol-based resin layer 6 has a thickness within this range, the dichroic dye has good dyeability, excellent polarization performance, and a thickness of 10 μm or less through the stretching step S20 and the dyeing step S30 described later. Child 5 can be obtained. When the thickness of the polyvinyl alcohol-based resin layer 6 exceeds 30 μm, the thickness of the polarizer 5 may exceed 10 μm. Further, if the thickness of the polyvinyl alcohol-based resin layer 6 is less than 3 μm, it tends to be too thin after stretching and the dyeability tends to be deteriorated.

Prior to coating the coating liquid, in order to improve the adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6, at least on the surface of the base film 30 on the side where the polyvinyl alcohol-based resin layer 6 is formed. , Corona treatment, plasma treatment, frame (flame) treatment and the like may be performed.

Further, prior to coating the coating liquid, in order to improve the adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6, a polyvinyl alcohol-based film is placed on the base film 30 via a primer layer or an adhesive layer. The resin layer 6 may be formed.

[Primer layer]
The primer layer can be formed by applying a coating liquid for forming a primer layer to the surface of the base film 30 and then drying it. The coating liquid for forming the primer layer contains a component that exerts a certain degree of strong adhesion to both the base film 30 and the polyvinyl alcohol-based resin layer 6. The coating liquid for forming a primer layer usually contains a resin component and a solvent that impart such adhesion. As the resin component, a thermoplastic resin having excellent transparency, thermal stability, stretchability and the like is preferably used, and examples thereof include (meth) acrylic resin and polyvinyl alcohol resin. Of these, polyvinyl alcohol-based resins that provide good adhesion are preferably used.

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol resins and derivatives thereof. Derivatives of polyvinyl alcohol resin include polyvinyl formal, polyvinyl acetal, etc., and polyvinyl alcohol resin modified with olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid. Modified products; those modified with an alkyl ester of unsaturated carboxylic acid; those modified with acrylamide, and the like can be mentioned. Among the above-mentioned polyvinyl alcohol-based resins, it is preferable to use a polyvinyl alcohol resin.

As the solvent, a general organic solvent or an aqueous solvent capable of dissolving the above resin component is usually used. Examples of solvents include aromatic hydrocarbons such as benzene, toluene and xylene; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and isobutyl acetate; methylene chloride, Chlorinated hydrocarbons such as trichloroethylene and chloroform; alcohols such as ethanol, 1-propanol, 2-propanol and 1-butanol. However, if the primer layer is formed using a primer layer forming coating solution containing an organic solvent, the base film 30 may be dissolved. Therefore, the solvent is selected in consideration of the solubility of the base film 30. It is preferable to do so. Considering the influence on the environment, it is preferable to form the primer layer from the coating liquid using water as a solvent.

In order to increase the strength of the primer layer, a cross-linking agent may be added to the coating liquid for forming the primer layer. As the cross-linking agent, an appropriate one is appropriately selected from known organic and inorganic cross-linking agents according to the type of thermoplastic resin to be used. Examples of cross-linking agents are, for example, epoxy-based, isocyanate-based, dialdehyde-based, and metal-based cross-linking agents.

As the epoxy-based cross-linking agent, either a one-component curing type or a two-component curing type can be used, and ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerindi or tri-glycidyl ether, 1,6-hexane. Examples thereof include diol diglycidyl ether, trimethyl propan triglycidyl ether, diglycidyl aniline, and diglycidyl amine.

Examples of the isocyanate-based cross-linking agent include tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane-tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylenebis (4-phenylmethane) triisocyanate, isophorone diisocyanate, and ketooximes thereof. Examples include block products and phenol block products.

Examples of the dialdehyde-based cross-linking agent include glyoxal, malondialdehyde, succindialdehyde, glutardaldehyde, malondialdehyde, phthaldialdehyde and the like.

Examples of the metal-based cross-linking agent include metal salts, metal oxides, metal hydroxides, and organometallic compounds. Examples of metal salts, metal oxides, and metal hydroxides include divalent or higher valences such as magnesium, calcium, aluminum, iron, nickel, zirconium, titanium, silicon, boron, zinc, copper, vanadium, chromium, and tin. Examples include salts, oxides and hydroxides of metal having a valence.

The organic metal compound is a compound having at least one structure in the molecule in which an organic group is directly bonded to a metal atom or an organic group is bonded via an oxygen atom, a nitrogen atom, or the like. The organic group means a monovalent or polyvalent group containing at least a carbon element, and can be, for example, an alkyl group, an alkoxy group, an acyl group, or the like. Further, the bond does not mean only a covalent bond, but may be a coordinate bond by coordination such as a chelate compound.

Preferable examples of organometallic compounds include organotitanium compounds, organozirconium compounds, organoaluminum compounds, and organosilicon compounds. As the organometallic compound, only one kind may be used alone, or two or more kinds may be used in combination.

Organic titanium compounds include, for example, titanium orthoesters such as tetranormal butyl titanate, tetraisopropyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate; titanium acetylacetonate, titanium tetraacetylacetonate. , Titanium acetylacetonate, titanium octylene glycolate, titanium lactate, titanium triethanolaminate, titanium chelates such as titanium ethyl acetoacetate; titanium acylates such as polyhydroxytitanium stearate.

Examples of the organic zirconium compound include zirconium normal propionate, zirconium normal butyrate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium acetylacetonate bisethylacetoacetate and the like.

Examples of the organoaluminum compound include aluminum acetylacetonate and aluminum organic acid chelate. Examples of the organic silicon compound include compounds in which the ligands exemplified above in the organic titanium compound and the organic zirconium compound are bonded to silicon.

In addition to the above low molecular weight cross-linking agents, high molecular weight cross-linking agents such as methylolated melamine resin and polyamide epoxy resin can also be used. Examples of commercially available polyamide epoxy resins include "Smiley's Resin 650 (30)" and "Smiley's Resin 675" (both are trade names) sold by Taoka Chemical Industry Co., Ltd.

When a polyvinyl alcohol-based resin is used as the resin component forming the primer layer, a polyamide epoxy resin, a methylolated melamine resin, a dialdehyde-based cross-linking agent, a metal chelate compound-based cross-linking agent, or the like is preferably used as the cross-linking agent.

The ratio of the resin component and the cross-linking agent in the coating liquid for forming the primer layer ranges from about 0.1 to 100 parts by weight of the cross-linking agent with respect to 100 parts by weight of the resin component, and the type of the resin component and the type of the cross-linking agent. It may be appropriately determined according to the above, and it is particularly preferable to select from the range of about 0.1 to 50 parts by weight. Further, it is preferable that the coating liquid for forming the primer layer has a solid content concentration of about 1 to 25% by weight.

The thickness of the primer layer is preferably about 0.05 to 1 μm, more preferably 0.1 to 0.4 μm. If it is thinner than 0.05 μm, the effect of improving the adhesion between the base film 30 and the polyvinyl alcohol-based resin layer 6 is small, and if it is thicker than 1 μm, it is disadvantageous for thinning the polarizing plate.

The method of applying the primer layer forming coating liquid to the base film 30 can be the same as the coating liquid for forming the polyvinyl alcohol-based resin layer. The primer layer is applied to the surface (one side or both sides of the base film 30) to which the coating liquid for forming the polyvinyl alcohol-based resin layer is applied. The drying temperature and drying time of the coating layer composed of the coating liquid for forming the primer layer are set according to the type of the solvent contained in the coating liquid. The drying temperature is, for example, 50 to 200 ° C, preferably 60 to 150 ° C. When the solvent contains water, the drying temperature is preferably 80 ° C. or higher. The drying time is, for example, 30 seconds to 20 minutes.

When the primer layer is provided, the order of coating on the base film 30 is not particularly limited. For example, when the polyvinyl alcohol-based resin layer 6 is formed on both sides of the base film 30, the base film 30 is provided. After forming the primer layers on both sides of the above, the polyvinyl alcohol-based resin layer 6 may be formed on both sides, or after forming the primer layer and the polyvinyl alcohol-based resin layer 6 on one surface of the base film 30 in this order, A primer layer and a polyvinyl alcohol-based resin layer 6 may be formed in this order on the other surface of the base film 30.

(2) Stretching step S20
With reference to FIG. 6, this step comprises stretching the laminated film 100 composed of the base film 30 and the polyvinyl alcohol-based resin layer 6 and forming the stretched base film 30'and the polyvinyl alcohol-based resin layer 6'. This is a step of obtaining a stretched film 200. The stretching treatment is usually uniaxial stretching.

The draw ratio of the laminated film 100 can be appropriately selected according to the desired polarization characteristics, but is preferably more than 5 times and 17 times or less, more preferably more than 5 times the original length of the laminated film 100. It is 8 times or less. If the draw ratio is 5 times or less, the polyvinyl alcohol-based resin layer 6 is not sufficiently oriented, so that the degree of polarization of the polarizer 5 may not be sufficiently high. On the other hand, if the draw ratio exceeds 17 times, the film is likely to break during stretching, and the thickness of the stretched film 200 becomes thinner than necessary, which may reduce workability and handleability in a subsequent process.

The stretching treatment is not limited to one-stage stretching, and can be performed in multiple stages. In this case, all of the multi-step stretching treatment may be continuously performed before the dyeing step S30, or the second and subsequent stretching treatments may be performed at the same time as the dyeing treatment and / or the cross-linking treatment in the dyeing step S30. Good. When the stretching treatment is performed in multiple stages in this way, it is preferable to perform the stretching treatment so that the total stretching ratio of all the stages of the stretching treatment is more than 5 times.

The stretching treatment may be a longitudinal stretching that stretches in the film longitudinal direction (film transport direction), or may be a transverse stretching or an oblique stretching that stretches in the film width direction. Examples of the longitudinal stretching method include inter-roll stretching using rolls, compression stretching, stretching using a chuck (clip), and the like, and examples of the transverse stretching method include a tenter method. As the stretching treatment, either a wet stretching method or a dry stretching method can be adopted, but it is preferable to use the dry stretching method because the stretching temperature can be selected from a wide range.

The stretching temperature is set to be equal to or higher than a temperature at which the polyvinyl alcohol-based resin layer 6 and the entire base film 30 exhibit fluidity to the extent that they can be stretched, and preferably the phase transition temperature (melting point or glass transition temperature) of the base film 30. It is in the range of −30 ° C. to + 30 ° C., more preferably in the range of −30 ° C. to + 5 ° C., and even more preferably in the range of −25 ° C. to + 0 ° C. When the base film 30 is composed of a plurality of resin layers, the phase transition temperature means the highest phase transition temperature among the phase transition temperatures exhibited by the plurality of resin layers.

When the stretching temperature is lower than the phase transition temperature of −30 ° C., it is difficult to achieve high-magnification stretching of more than 5 times, or the fluidity of the base film 30 is too low and the stretching treatment tends to be difficult. When the stretching temperature exceeds the phase transition temperature of + 30 ° C., the fluidity of the base film 30 tends to be too large and stretching tends to be difficult. Since it is easier to achieve a high stretching ratio of more than 5 times, the stretching temperature is within the above range, more preferably 120 ° C. or higher. This is because when the stretching temperature is 120 ° C. or higher, the stretching treatment is not difficult even at a high stretching ratio of more than 5 times.

The method for heating the laminated film 100 in the stretching treatment is a zone heating method (for example, a method of heating in a stretching zone such as a heating furnace in which hot air is blown and adjusted to a predetermined temperature); in the case of stretching using a roll. , A method of heating the roll itself; a heater heating method (a method of installing an infrared heater, a halogen heater, a panel heater, etc. above and below the laminated film 100 and heating with radiant heat) and the like. In the inter-roll stretching method, the zone heating method is preferable from the viewpoint of uniformity of stretching temperature. In this case, the two nip roll pairs may be installed in the temperature-controlled stretching zone or outside the stretching zone, but are installed outside the stretching zone in order to prevent adhesion between the laminated film 100 and the nip roll. It is preferable to do so.

The stretching temperature means the atmospheric temperature in the zone (for example, in the heating furnace) in the case of the zone heating method, and also means the atmospheric temperature in the furnace when heating is performed in the furnace in the heater heating method. In the case of a method of heating the roll itself, it means the surface temperature of the roll.

Prior to the stretching step S20, a preheat treatment step for preheating the laminated film 100 may be provided. As the preheating method, the same method as the heating method in the stretching treatment can be used. When the stretching treatment method is inter-roll stretching, the preheating may be performed at any timing before, during, or after passing through the nip roll on the upstream side. When the stretching treatment method is thermal roll stretching, preheating is preferably performed at a timing before passing through the thermal roll. When the stretching treatment method is stretching using a chuck, the preheating is preferably performed at a timing before increasing the distance between the chucks. The preheating temperature is preferably in the range of −50 ° C. to ± 0 ° C. of the stretching temperature, and more preferably in the range of −40 ° C. to −10 ° C. of the stretching temperature.

Further, a heat fixing treatment step may be provided after the stretching treatment in the stretching step S20. The heat fixing treatment is a treatment in which heat treatment is performed at a crystallization temperature or higher while maintaining a tense state while the end portion of the stretched film 200 is gripped by a clip. This heat fixing treatment promotes the crystallization of the polyvinyl alcohol-based resin layer 6'. The temperature of the heat fixing treatment is preferably in the range of −0 ° C. to −80 ° C. of the stretching temperature, and more preferably in the range of −0 ° C. to −50 ° C. of the stretching temperature.

(3) Dyeing step S30
With reference to FIG. 7, this step is a step of dyeing the polyvinyl alcohol-based resin layer 6'of the stretched film 200 with a dichroic dye and adsorbing and orienting the polyvinyl alcohol-based resin layer 6'to form a polarizer 5. Through this step, a polarizing laminated film 300 in which the polarizer 5 is laminated on one side or both sides of the base film 30'is obtained.

The dyeing step can be performed by immersing the entire stretched film 200 in a solution containing a dichroic dye (dyeing solution). As the dyeing solution, a solution in which the above dichroic dye is dissolved in a solvent can be used. Water is generally used as the solvent for the dyeing solution, but an organic solvent compatible with water may be further added. The concentration of the dichroic dye in the dyeing solution is preferably 0.01 to 10% by weight, more preferably 0.02 to 7% by weight, and further preferably 0.025 to 5% by weight. preferable.

When iodine is used as the dichroic dye, it is preferable to further add iodide to the dyeing solution containing iodine because the dyeing efficiency can be further improved. 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. Can be mentioned. The concentration of iodide in the dyeing solution is preferably 0.01 to 20% by weight. Among the iodides, it is preferable to add potassium iodide. When potassium iodide is added, the ratio of iodine to potassium iodide is preferably in the range of 1: 5 to 1: 100, more preferably in the range of 1: 6 to 1:80 by weight. It is preferably in the range of 1: 7 to 1:70, even more preferably.

The immersion time of the stretched film 200 in the dyeing solution is usually in the range of 15 seconds to 15 minutes, preferably 30 seconds to 3 minutes. The temperature of the dyeing solution is preferably in the range of 10 to 60 ° C, more preferably in the range of 20 to 40 ° C.

Although it is possible to perform the dyeing step S30 before the stretching step S20 or to perform these steps at the same time, the dichroic dye to be adsorbed on the polyvinyl alcohol-based resin layer can be satisfactorily oriented. As described above, it is preferable to carry out the dyeing step S30 after applying at least a certain amount of stretching treatment to the laminated film 100. That is, the stretched film 200 obtained by subjecting the stretching treatment to a target magnification in the stretching step S20 can be subjected to the dyeing step S30, and after the stretching treatment is performed in the stretching step S20 at a magnification lower than the target. In the dyeing step S30, the stretching treatment can be performed until the total stretching ratio reaches the target magnification. In the latter embodiment, 1) the stretching treatment is performed at a magnification lower than the target in the stretching step S20, and then the stretching treatment is performed so that the total stretching ratio becomes the target magnification during the dyeing treatment in the dyeing step S30. As will be described later, when the cross-linking treatment is performed after the dyeing treatment, 2) after the stretching treatment is performed at a magnification lower than the target in the stretching step S20, the total stretching ratio is the target during the dyeing treatment in the dyeing step S30. The stretching treatment is performed to the extent that the magnification does not reach the above-mentioned magnification, and then the stretching treatment is performed during the cross-linking treatment so that the final total stretching ratio becomes the target magnification.

The dyeing step S30 can include a cross-linking treatment step carried out following the dyeing treatment. The cross-linking treatment can be performed by immersing the dyed film in a solution containing a cross-linking agent (cross-linking solution). As the cross-linking agent, conventionally known substances can be used, and examples thereof include boric acid, boron compounds such as borax, glyoxal, and glutaraldehyde. Only one type of cross-linking agent may be used alone, or two or more types may be used in combination.

Specifically, the cross-linking solution can be a solution in which a cross-linking agent is dissolved in a solvent. As the solvent, for example, water can be used, but an organic solvent compatible with water may be further contained. The concentration of the cross-linking agent in the cross-linking solution is preferably in the range of 1 to 20% by weight, more preferably in the range of 6 to 15% by weight.

The cross-linking solution can include iodide. By adding iodide, the in-plane polarization performance of the polarizer 5 can be made more uniform. 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. Can be mentioned. The concentration of iodide in the crosslinked solution is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight.

The immersion time of the dyed film in the cross-linking solution is usually 15 seconds to 20 minutes, preferably 30 seconds to 15 minutes. The temperature of the crosslinked solution is preferably in the range of 10 to 90 ° C.

The cross-linking treatment can also be performed at the same time as the dyeing treatment by blending a cross-linking agent in the dyeing solution. Further, the stretching treatment may be performed during the crosslinking treatment. The specific embodiment in which the stretching treatment is carried out during the crosslinking treatment is as described above. Further, the treatment of immersing in the cross-linking solution may be performed twice or more by using two or more kinds of cross-linking solutions having different compositions.

It is preferable to perform a washing step and a drying step after the dyeing step S30 and before the first bonding step S40 described later. The cleaning step usually includes a water cleaning step. The water washing treatment can be performed by immersing the film after the dyeing treatment or the cross-linking treatment in pure water such as ion-exchanged water or distilled water. The water washing temperature is usually in the range of 3 to 50 ° C, preferably 4 to 20 ° C. The immersion time in water is usually 2 to 300 seconds, preferably 3 to 240 seconds.

The cleaning step may be a combination of a water cleaning step and a cleaning step with an iodide solution. In addition to water, the cleaning liquid used in the water cleaning step and / or the cleaning treatment with the iodide solution may appropriately contain liquid alcohols such as methanol, ethanol, isopropyl alcohol, butanol, and propanol.

As the drying step performed after the washing step, any suitable method such as natural drying, blast drying, and heat drying can be adopted. For example, in the case of heat drying, the drying temperature is usually 20 to 95 ° C., and the drying time is usually about 1 to 15 minutes.

(4) First bonding step S40
With reference to FIG. 8, in this step, the first step is performed on the polarizer 5 of the polarizing laminated film 300, that is, on the surface of the polarizing element 5 opposite to the base film 30'side, via the adhesive layer. This is a step of bonding either the protective film 10 or the second protective film 20 to obtain the bonded film 400. FIG. 8 shows an example in which the first protective film 10 is bonded via the first adhesive layer 15, but the second protective film 20 is bonded via the second adhesive layer 25. May be good. When the polarizing laminated film 300 has the polarizers 5 on both sides of the base film 30', the protective films are usually bonded onto the polarizers 5 on both sides. In this case, these protective films may be the same type of protective film or different types of protective films.

The protective film (first protective film 10 or second protective film 20) is attached to the polarizer 5 via an adhesive layer (first adhesive layer 15 or second adhesive layer 25).

In the bonding of the protective film via the adhesive layer, for example, an adhesive is applied to the bonding surface of the protective film and / or the polarizer 5 by a known means, and the adhesive is applied through the coating layer of the adhesive. A method of superimposing the protective film and the polarizer 5 and laminating them using a laminating roll or the like can be mentioned.

In order to reduce the thickness of the adhesive layer as in the first adhesive layer 15, a method of applying an adhesive using a small-diameter gravure or the like is preferable, and in particular, a gravure rotation draw (gravure rotation speed with respect to the line speed). The thickness of the adhesive layer can be reduced by increasing the ratio) to increase the rotation speed of the gravure or increasing the number of lines of the gravure mesh. In particular, in order to reduce the thickness of the adhesive layer to 1 μm or less, it is preferable to use a gravure in which a mesh is carved by laser engraving, and it is particularly preferable to use a honeycomb-shaped gravure roll. For example, a honeycomb shape having more than 400 rows of honeycombs per inch is preferably used.

When a photocurable adhesive is used as the adhesive, after performing the above-mentioned bonding, a curing step of curing the photocurable adhesive by irradiating with active energy rays is performed. The light source of the active energy ray is not particularly limited, but an active energy ray (ultraviolet ray) having an emission distribution at a wavelength of 400 nm or less is preferable, and specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, and the like. A black light lamp, a microwave-excited mercury lamp, a metal halide lamp, or the like is preferably used.

The light irradiation intensity of the photocurable adhesive is appropriately determined by the composition of the photocurable adhesive, and the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1 to 6000 mW / cm ² . It is preferable that the setting is as follows. When the irradiation intensity is 0.1 mW / cm ² or more, the reaction time does not become too long, and when it is 6000 mW / cm ² or less, the heat radiated from the light source and the light generated by the heat generated when the photocurable adhesive is cured. There is little risk of yellowing of the curable adhesive and deterioration of the polarizer 5.

The light irradiation time of the photocurable adhesive is also appropriately determined by the composition of the photocurable adhesive, but the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 to 10,000 mJ / cm ² . It is preferable that the setting is as follows. If the integrated light quantity is 10 mJ / cm ² or more to generate a sufficient amount of the active species derived from the polymerization initiator can proceed more reliably the curing reaction, if it is 10000 mJ / cm ² or less, longer irradiation time Good productivity can be maintained without becoming too much.

When a water-based adhesive is used, usually, after bonding, a drying step of drying is carried out in order to remove water contained in the water-based adhesive. Drying can be performed, for example, by introducing the bonded film into a drying oven. The drying temperature (temperature of the drying oven) is preferably 30 to 90 ° C. If the temperature is lower than 30 ° C., the protective film tends to be easily peeled off from the polarizer 5. Further, if the drying temperature exceeds 90 ° C., the polarization performance of the polarizer 5 may be deteriorated by heat. The drying time can be about 10 to 1000 seconds.

After the drying step, a curing step may be provided in which the mixture is cured at room temperature or a temperature slightly higher than that, for example, at a temperature of about 20 to 45 ° C. for about 12 to 600 hours. The curing temperature is generally set lower than the drying temperature.

When the protective film is attached onto the polarizer 5, the surface of the protective film on the polarizer 5 side is subjected to plasma treatment, corona treatment, ultraviolet irradiation treatment, and frame (flame) in order to improve the adhesiveness with the polarizer 5. ) Treatment, surface treatment such as saponification treatment (easy adhesion treatment) can be performed, and among them, plasma treatment, corona treatment, or saponification treatment is preferable. For example, when the protective film is made of a cyclic polyolefin resin, plasma treatment or corona treatment is usually performed. When it is made of a cellulose ester resin, it is usually saponified. Examples of the saponification treatment include a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide.

(5) Peeling step S50
With reference to FIG. 9, this step is a step of peeling and removing the base film 30'from the bonded film 400 obtained by bonding the protective film. Through this step, a polarizing plate 500 with a single-sided protective film in which a protective film (first protective film 10 in the example of FIG. 9) is laminated on one side of the polarizer 5 is obtained. When the polarizing laminated film 300 has a polarizing element 5 on both sides of the base film 30'and a protective film is attached to both of these polarizing elements 5, one polarizing layer is laminated by this peeling step S50. From the film 300, two polarizing plates 500 with a single-sided protective film can be obtained.

The method for peeling and removing the base film 30'is not particularly limited, and the base film 30'can be peeled by the same method as the peeling step of the separator (peeling film) performed by a normal polarizing plate with an adhesive. The base film 30'may be peeled off as it is after the first bonding step S40, or after the first bonding step S40, it is wound once in a roll shape and then peeled off while being unwound in the subsequent steps. You may.

(6) Second bonding step S60
In this step, the first and second steps are performed on the polarizing element 5 of the polarizing plate 500 with a single-sided protective film, that is, on the surface opposite to the protective film bonded in the first bonding step S40, via an adhesive layer. This is a step of laminating the other protective film of the protective films 10 and 20 to obtain the polarizing plate 1 according to the present invention with the double-sided protective film as shown in FIG. Regarding the method of bonding the protective film and the surface treatment (easy bonding process) in the bonding, the contents described in the first bonding step S40 are cited.

<Display device>
The display device of the present invention includes a display cell 50 and a polarizing plate 1 according to the present invention arranged on at least one surface of the display cell 50 with reference to FIG. The polarizing plate 1 can be arranged and bonded on the display cell 50 by using the adhesive layer 60 provided on the outer surface of the second protective film 20 arranged on the display cell 50 side. In such a display device, the first protective film 10 of the polarizing plate 1 forms the outer surface (typically the outermost surface) of the display device, but according to the present invention, the unevenness on the surface of the first protective film 10 is effective. The appearance of the display device is excellent because it can be suppressed. In addition, light leakage in the black display state can be effectively suppressed.

A typical example of the display device is a liquid crystal display device in which the display cell 50 is a liquid crystal cell, but another display device such as an organic EL device may be used. In the display device, the polarizing plate may be arranged on at least one surface of the display cell 50, but may be arranged on both sides.

When the display device is a liquid crystal display device, polarizing plates are usually arranged on both sides of the liquid crystal cell. In this case, the polarizing plates on both sides may be the polarizing plates according to the present invention, or only one polarizing plate may be the polarizing plate according to the present invention. In the latter, the polarizing plate according to the present invention may be a polarizing plate on the front side (visual recognition side) or a polarizing plate on the rear side (backlight side) with reference to the liquid crystal cell. As the liquid crystal cell, a conventionally known type can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these examples.

<Example 1>
(1) Primer layer forming step Polyvinyl alcohol powder (“Z-200” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average degree of polymerization 1100, saponification degree 99.5 mol%) was dissolved in hot water at 95 ° C. A polyvinyl alcohol aqueous solution having a concentration of 3% by weight was prepared. A cross-linking agent (“Sumirace Resin 650” manufactured by Taoka Chemical Industry Co., Ltd.) is mixed with the obtained aqueous solution at a ratio of 5 parts by weight to 6 parts by weight of polyvinyl alcohol powder, and a coating liquid for forming a primer layer is used. Got

Next, an unstretched polypropylene (PP) film (melting point: 163 ° C.) having a thickness of 90 μm was prepared as a base film, and one side of the unstretched polypropylene (PP) film (melting point: 163 ° C.) was subjected to corona treatment. A primer layer having a thickness of 0.2 μm was formed by applying a coating liquid for forming a primer layer and drying at 80 ° C. for 10 minutes.

(2) Preparation of laminated film (resin layer forming step)
Polyvinyl alcohol powder (“PVA124” manufactured by Kuraray Co., Ltd., average degree of polymerization 2400, saponification degree 98.0-99.0 mol%) is dissolved in hot water at 95 ° C., and a polyvinyl alcohol aqueous solution having a concentration of 8% by weight is dissolved. Was prepared and used as a coating liquid for forming a polyvinyl alcohol-based resin layer.

The surface of the primer layer of the base film having the primer layer prepared in (1) above is coated with the above-mentioned coating liquid for forming a polyvinyl alcohol-based resin layer using a lip coater, and then dried at 80 ° C. for 20 minutes. A polyvinyl alcohol-based resin layer was formed on the primer layer to obtain a laminated film composed of a base film / primer layer / polyvinyl alcohol-based resin layer.

(3) Preparation of stretched film (stretching step)
The laminated film produced in (2) above was subjected to 5.8-fold free-end uniaxial stretching at 160 ° C. using a floating longitudinal uniaxial stretching device to obtain a stretched film. The thickness of the polyvinyl alcohol-based resin layer after stretching was 6.1 μm.

(4) Preparation of Polarizing Laminated Film (Dyeing Step)
The stretched film prepared in (3) above is placed in a dyeing aqueous solution containing iodine and potassium iodide at 30 ° C. (containing 0.6 parts by weight of iodine and 10 parts by weight of potassium iodide per 100 parts by weight of water). After immersing for 180 seconds to dye the polyvinyl alcohol-based resin layer, excess dyeing aqueous solution was washed away with pure water at 10 ° C.

Then, it is immersed in a first crosslinked aqueous solution containing boric acid at 78 ° C. (containing 9.5 parts by weight of boric acid per 100 parts by weight of water) for 120 seconds, and then at 70 ° C. containing boric acid and potassium iodide. The cross-linking treatment was carried out by immersing in a 2-crosslinked aqueous solution (containing 9.5 parts by weight of boric acid and 4 parts by weight of potassium iodide per 100 parts by weight of water) for 60 seconds. Then, it was washed with pure water at 10 ° C. for 10 seconds, and finally dried at 40 ° C. for 300 seconds to obtain a polarizing laminated film composed of a base film / primer layer / polarizer.

(5) Fabrication of polarizing plate (first bonding step, peeling step, second bonding step)
A cyclic polyolefin resin film (“ZF14” manufactured by Nippon Zeon Corporation, thickness 23 μm) was prepared as the first protective film to be arranged on the outside (visual side) when the polarizing plate was arranged on the display cell. .. After corona treatment is applied to the bonded surface of the first protective film, a photocurable adhesive (“KR-70T” manufactured by ADEKA Corporation) is applied to the corona treated surface using a small-diameter gravure coater. Then, the first protective film was placed on the polarizer of the polarizing laminated film produced in (4) above via the coating layer of the adhesive, and then bonded using a bonding roll. Next, the adhesive is cured by irradiation with ultraviolet rays to form a first adhesive layer, and a bonded film having a layer structure of a first protective film / first adhesive layer / polarizer / primer layer / base film is obtained. (1st bonding process). _{The thickness T 1} of the first adhesive layer was 0.2 μm.

Next, the base film was peeled off and removed from the obtained bonding film (peeling step). The base film was easily peeled off to obtain a polarizing plate with a single-sided protective film having a layer structure of a first protective film / a first adhesive layer / a polarizer / a primer layer.

As a second protective film to be arranged on the display cell side when the polarizing plate is arranged on the display cell, a cyclic polyolefin resin film (“ZF14” manufactured by Nippon Zeon Corporation, thickness 23 μm) was prepared. After corona treatment is applied to the bonded surface of the second protective film, a photocurable adhesive (“KR-70T” manufactured by ADEKA Corporation) is applied to the corona treated surface using a small-diameter gravure coater. Then, the second protective film is placed on the surface of the obtained polarizing plate with a single-sided protective film opposite to the first protective film via the coating layer of the adhesive, and then bonded using a bonding roll. It fits. Next, the adhesive is cured by irradiation with ultraviolet rays to form a second adhesive layer, and the layer structure of the first protective film / first adhesive layer / polarizer / primer layer / second adhesive layer / second protective film is formed. A polarizing plate made of _{The thickness T 2} of the second adhesive layer was 1.3 μm.

_{The thicknesses T 1} and T ₂ of the first and second adhesive layers were measured as follows. That is, the "thickness of the first or second protective film" before the application of the photocurable adhesive and the "first or second protective film" after the application of the photocurable adhesive (before bonding with the polarizer). And the total thickness of the coated adhesive layer ”was measured using a non-contact optical interference type film thickness meter (“F-20” manufactured by Filmometrics Co., Ltd.), and the difference between them was measured in the first and first positions. 2 The thicknesses of the adhesive layers were T ₁ and T ₂ . The thickness of the adhesive layer before bonding with the polarizing element and curing thus obtained is maintained almost as it is after bonding with the polarizing element and curing, and the bonding after curing in the obtained polarizing plate is maintained. The fact that the thickness is substantially the same as the thickness of the agent layer is confirmed by cutting out a cross section of the obtained polarizing plate, observing the thickness of the adhesive layer in the cross section with an SEM (scanning electron microscope), and actually measuring the thickness. ing.

<Examples 2 to 5, Comparative Examples 1 to 2>
A polarizing plate was produced in the same manner as in Example 1 except that _{the thicknesses T 1} and T ₂ of the first and second adhesive layers were as shown in Table 1.

[Evaluation of reflection image distortion and light leakage]
(1) Evaluation of distortion of reflected image The polarizing plates obtained in Examples and Comparative Examples were cut out to a size of 4 "and attached to one side of a liquid crystal cell via an adhesive layer on the second protective film side for evaluation. A fluorescent lamp was projected on the surface of the first protective film of the evaluation sample by normal reflection, and the distortion of the reflected image was visually evaluated according to the following evaluation criteria. The results are shown in Table 1.

A: There is no distortion and the reflected image is extremely clear.
B: There is almost no distortion and the reflected image is clear.
C: Slightly distorted, but a relatively clear reflection image is obtained,
D: The distortion is large.

(2) Light Leakage Evaluation A polarizing plate of 4 "size was attached to the other surface of the liquid crystal cell in the evaluation sample used in (1) above in the same manner. At this time, the polarizing plates on the other surface were attached to the front and back surfaces. The polarizing plates of the above were bonded so as to form cross Nicols (so that the absorption axes of the polarizers were orthogonal to each other). Light was irradiated from the first protective film surface side of one of the polarizing plates in the obtained evaluation sample. The presence or absence of light transmitted through the first protective film side of the other polarizing plate in the black display state (light leakage) was visually evaluated according to the following evaluation criteria. The results are shown in Table 1.

A: No light leakage,
B: Light leakage is observed (bright spots are present).

1 Platelet, 5 Polarizer, 10 1st protective film, 15 1st adhesive layer, 20 2nd protective film, 25 2nd adhesive layer, 6 Polyvinyl alcohol resin layer, 6'stretched polyvinyl alcohol resin Layer, 30 base film, 30'stretched base film, 50 display cell, 60 adhesive layer, 100 laminated film, 200 stretched film, 300 polarized laminated film, 400 laminated film, 500 with single-sided protective film Polarizer.

Claims (6)

Polarizer and
A first protective film laminated on one surface of the polarizer via a first adhesive layer having a thickness of less than 2.0 μm.
A second protective film laminated on the other surface of the polarizer via a second adhesive layer having a thickness of 2.0 μm or less.
It is a polarizing plate containing
The first and second protective films are transparent resin films.
A hard coat layer, an antiglare layer, an antireflection layer, or an antifouling layer is formed on the surface of the first protective film opposite to the polarizer.
The second protective film is a protective film that is arranged closer to the display cell than the first protective film when the polarizing plate is arranged on the display cell.
The thickness of the first and second protective films is 23 μm or less, and the thickness is 23 μm or less.
The thickness of the first adhesive layer is rather smaller than the thickness of the second adhesive layer,
The first and second adhesive layers are polarizing plates that are a cured product layer of a photocurable adhesive. The polarizing plate according to claim 1, wherein the thickness of the polarizer is 10 μm or less. The polarizing plate according to claim 1 or 2 , further comprising an adhesive layer for bonding to the display cell, which is laminated on the outer surface of the second protective film. A display device including a display cell and a polarizing plate according to any one of claims 1 to 3 arranged on at least one surface thereof. A display device including a display cell and the polarizing plate according to claim 3 arranged on at least one surface thereof, and the polarizing plate is attached to the display cell via the pressure-sensitive adhesive layer. The method for using a polarizing plate according to any one of claims 1 to 3.
A method of using a polarizing plate, in which the second protective film is arranged closer to the display cell than the first protective film when the polarizing plate is arranged on the display cell.

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