KR20140006800A - Methods for producing polarizing laminate film and polarizing plate - Google Patents

Abstract

The present invention provides a resin film bonding step of bonding a resin film made of polyvinyl alcohol-based resin having a thickness of 50 µm or less to one surface of a base film to obtain a laminated film, a stretching step of uniaxially stretching the laminated film, and the uniaxial stretching Production of a polarizing laminated film comprising a base film comprising a dyeing step of dyeing the resin film of the laminated film with a dichroic dye to form a polarizer layer in this order and a polarizer layer formed on one side of the base film. Provide a method. According to this invention, the method of manufacturing the light-polarizing laminated film which has a thin polarizer layer can be provided, without causing the problem that the edge part of a base film is folded in.

Description

The manufacturing method of a polarizing laminated film and a polarizing plate {METHODS FOR PRODUCING POLARIZING LAMINATE FILM AND POLARIZING PLATE}

This invention relates to the manufacturing method of a polarizing laminated film and a polarizing plate.

BACKGROUND ART A polarizing plate is widely used as a polarizing light supply element in a display device such as a liquid crystal display device. As such a polarizing plate, a polarizer layer made of a polyvinyl alcohol-based resin and a protective film such as triacetylcellulose laminated are conventionally used. In a polarizer layer (polarizing film), high optical performance is calculated | required, and thickness reduction is calculated | required in recent years by development to mobile devices, such as a notebook type personal computer and a mobile telephone of a liquid crystal display device.

As an example of the manufacturing method of a polarizing plate, after extending | stretching the film which consists of polyvinyl alcohol-type resin independently, or extending | stretching, it carries out a dyeing process or crosslinking process, produces a polarizing film, and manufactures a polarizing plate by laminating this on a protective film etc. Methods are known (see eg JPH11-49878-A).

As another example of the manufacturing method of a polarizing plate, after apply | coating the solution containing polyvinyl alcohol-type resin on the surface of a base film and providing a resin layer, the laminated | multilayer film which consists of a base film and a resin layer is extended | stretched, and then dyed, The method of forming a polarizer layer from a resin layer and obtaining the polarizing laminated film which has a polarizer layer is proposed (for example, refer JP2000-33829-A). The method which uses this as a polarizing plate as it is, or after bonding a protective film to this film and peeling off a base film is used as a polarizing plate.

As another example of the manufacturing method of a polarizing plate, the resin for protective films and polyvinyl alcohol-type resin are coextruded, a laminated film is produced, this laminated | multilayer film is stretched, and then dyed, and the polarizing plate which consists of a polarizer layer and a protective film A method of obtaining is proposed (see eg JP2009-25821-A).

However, in the method of producing a polarizing film by stretching, dyeing and crosslinking a film made of a polyvinyl alcohol-based resin alone, it is difficult to handle a thin film having a thickness of 50 μm or less, because breakage and wrinkles are likely to occur. Therefore, the realization of thickness reduction of a polarizing film is difficult.

In the method of apply | coating the solution containing polyvinyl alcohol-type resin to a surface of a base film, and providing a resin layer, a resin layer tends to shrink by dry shrinkage of the solution containing polyvinyl alcohol-type resin, As a result, a base film The end of the base film may be folded in the drying furnace or at the exit of the drying furnace by continuously flowing the base film with the resin layer in such a state. There is a case.

In the method for co-extrusion of the protective film resin and the polyvinyl alcohol-based resin to produce a laminated film, since the polyvinyl alcohol-based resin is usually melted and extruded together, extrusion of the base film is carried out in the same manner as described above. It may cause a problem that the end part is folded in.

Then, the objective of this invention is providing the method of manufacturing the polarizing laminated film and polarizing plate which have a thin polarizer layer, without causing the problem that the edge part of a base film is folded in.

The present invention includes the following.

[1] a resin film bonding step of bonding a resin film made of polyvinyl alcohol-based resin having a thickness of 50 μm or less to one side of a base film to obtain a laminated film;

An extending step of uniaxially stretching the laminated film;

A polarizing layer comprising a base film and a polarizer layer formed on one side of the base film, including a dyeing step of dyeing the resin film of the uniaxially-stretched laminated film with a dichroic dye to form a polarizer layer in this order. Method for producing a film.

[2] The method according to [1], in which the resin film is bonded to one surface of the base film through an adhesive layer or an adhesive layer in the resin film bonding step.

[3] The method according to [1] or [2], wherein the resin film bonding step has a thickness of 15 µm or more.

[4] The resin film used in the resin film bonding step includes a resin layer forming step of forming a resin layer made of polyvinyl alcohol-based resin on a support;

A first drying step of drying the resin layer, a resin layer separation step of peeling the resin layer from the support to obtain the resin layer,

Any one of [1]-[3] which is a resin film manufactured by the manufacturing method containing the 2nd drying process which dries this resin layer at the drying temperature higher than the temperature in a 1st drying process in this order. The method described in.

[5] After the polarizing laminated film is produced by the method described in [1],

The protective film bonding process of bonding a protective film to the surface on the opposite side to the surface of the said polarizer layer of the said polarizing layer in this polarizing laminated film,

The manufacturing method of the polarizing plate provided with the polarizer layer containing the base film peeling process which peels the said base film from this polarizing laminated film in this order, and the protective film formed in one surface of this polarizer layer.

According to this invention, the edge part of a base film does not fold in a manufacturing process, and the polarizing laminated film and polarizing plate which have a thin polarizer layer can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS It is a flowchart which shows one Embodiment of the manufacturing method of the polarizing laminated film of this invention.
It is a flowchart which shows one Embodiment of the manufacturing method of the polarizing plate of this invention.
3 is a flowchart showing an embodiment of a method for producing a polyvinyl alcohol-based resin film.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of the manufacturing method of the polarizing laminated film which concerns on this invention, and the manufacturing method of a polarizing plate is described in detail, referring drawings.

[Manufacturing method of polarizing laminated film]

BRIEF DESCRIPTION OF THE DRAWINGS It is a flowchart which shows one Embodiment of the manufacturing method of the polarizing laminated film which concerns on this invention. The polarizing laminated film manufactured by this embodiment is equipped with a base film and the polarizer layer formed in one surface of the base film. In the manufacturing method of the light-polarizing laminated film of this embodiment, the resin film bonding process (S10) which bonds the resin film which consists of polyvinyl alcohol-type resin to one surface of a base film, and obtains a laminated film, and uniaxially stretches this laminated | multilayer film is carried out. Stretching step (S20) to be performed and dyeing step (S30) of dyeing the resin film of this laminated film with a dichroic dye to form a polarizer layer are usually performed in this order.

In this specification, the laminated body by which the resin film (henceforth a "polyvinyl alcohol-type resin film") bonded by the resin film which consists of polyvinyl alcohol-type resin to one side of a base film is laminated | stacked, and has poly as a polarizer The laminated body which provided the vinyl alcohol-type resin film with a "polarizer layer" and the polarizer layer in one surface of a base film is called "polarizing laminated film." And the laminated body provided with the protective film in one surface of the polarizer layer is called "polarizing plate."

By the above-mentioned manufacturing method, the polarizing laminated film which has sufficient polarizing performance on the base film, for example, was provided with the polarizer layer of 25 micrometers or less in thickness. Preferably the thickness of the polarizer layer of the polarizing laminated film obtained by said manufacturing method is 25 micrometers or less, More preferably, it is 20 micrometers or less. This polarizing laminated film can also be used as an intermediate product for transferring a polarizer layer to a protective film as mentioned later, and when a base film has a function of a protective film, this polarizing laminated film is used as a polarizing plate as it is. It can also be used.

[Method of Manufacturing Polarizing Plate]

2 is a flowchart illustrating one embodiment of a method of manufacturing a polarizing plate according to the present invention. The polarizing plate manufactured by this embodiment is equipped with the polarizer layer and the protective film formed in one surface of the polarizer layer. The manufacturing method of the polarizing plate of this embodiment is a resin film bonding process (S10) which bonds a polyvinyl alcohol-type resin film to one surface of a base film, and obtains a laminated film, and the extending process (S20) which uniaxially stretches this laminated film. And after performing the dyeing process (S30) which dyes the polyvinyl alcohol-type resin film of this laminated film with a dichroic dye, and forms a polarizer layer normally in this order, and obtains a polarizing laminated film, in the polarizing laminated film Protective film bonding process (S40) which bonds a protective film to the surface on the opposite side to the surface on the base film side of the polarizer layer of this, and base film peeling process (S50) which peels a base film from a polarizing laminated film normally To have.

By the above manufacturing method, the polarizing plate which has sufficient polarizing performance on the protective film, for example, provided with the polarizer layer of 25 micrometers or less in thickness can be obtained. Preferably the thickness of the polarizer layer of the polarizing plate obtained by said manufacturing method is 25 micrometers or less, More preferably, it is 20 micrometers or less. This polarizing plate can be used, for example, by bonding to another optical film or a liquid crystal cell through a pressure-sensitive adhesive.

Hereinafter, each process of S10-S50 in FIG. 1 and FIG. 2 is demonstrated in detail. In addition, each process of S10-S30 of FIG. 1 and FIG. 2 is the same process.

<Resin film bonding step (S10)>

A polyvinyl alcohol-based resin film is bonded to one side of the base film. The joining method of a base film and a polyvinyl alcohol-type resin film will not be specifically limited if it is a method which does not peel even through a subsequent extending process (S20) and dyeing process (S30). For example, an adhesive layer or an adhesive layer is formed in the bonding surface of a polyvinyl alcohol-type resin film and / or a base film, and both are bonded together through an adhesive layer or an adhesive layer.

(Polyvinyl alcohol based resin film)

The thickness of the polyvinyl alcohol-type resin film used at a resin film bonding process shall be 50 micrometers or less. The polyvinyl alcohol-based resin film forms a polarizer layer via the following stretching step and dyeing step, but the polyvinyl alcohol-based resin film in the resin film bonding step (S10), that is, the polyvinyl alcohol-based resin film before stretching When the thickness exceeds 50 µm, the stretching step and the dyeing step can be handled without bonding with the base film as in the present invention, so the merit according to the present invention is small. Moreover, when the thickness of a polyvinyl alcohol-type resin film exceeds 50 micrometers, it may be difficult to form the thickness of a polarizer layer into 25 micrometers or less thin films. The thickness of the polyvinyl alcohol-based resin film (before stretching) is preferably 10 µm or more, more preferably 15 µm or more. When the thickness of a polyvinyl alcohol-type resin film is less than 10 micrometers, it is difficult to obtain a polyvinyl alcohol-type resin film independently. As for the thickness of a polyvinyl alcohol-type resin film, it is more preferable that they are 15 micrometers-45 micrometers.

As polyvinyl alcohol-type resin which forms a polyvinyl alcohol-type resin film, what saponified polyvinyl acetate type resin can be used. As polyvinyl acetate type resin, besides polyvinyl acetate which is a homopolymer of vinyl acetate, the copolymer etc. with the other monomer copolymerizable with vinyl acetate are illustrated. As another monomer copolymerizable with vinyl acetate, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamide which has an ammonium group, etc. are mentioned, for example.

The polyvinyl alcohol-based resin is preferably a completely saponified product. It is preferable that the range of saponification degree is 80 mol%-100 mol%, It is more preferable that it is the range of 90 mol%-100 mol%, Furthermore, it is most preferable that it is the range of 94 mol%-100 mol%. . If saponification degree is less than 80 mol%, there exists a problem that water resistance and heat-and-moisture resistance after forming a polarizer layer are remarkably inferior.

The saponification degree here shows the ratio which the acetic acid group contained in the polyvinyl acetate type resin which is a raw material of polyvinyl alcohol-type resin changed to the hydroxyl group by the saponification process by unit ratio (mol%), and is a numerical value defined by the following formula. It can obtain | require by the method prescribed | regulated to JISK6726 (1994).

Saponification degree (mol%) = (number of hydroxyl groups) ÷ (number of hydroxyl groups + number of acetic acid groups) × 100

The higher the degree of saponification, the higher the ratio of hydroxyl groups, that is, the lower the proportion of acetic acid groups that inhibit crystallization.

The polyvinyl alcohol-based resin may be a modified polyvinyl alcohol in which part of it is modified. Examples thereof include 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. It is preferable that it is less than 30 mol%, and, as for the ratio of denaturation, it is more preferable that it is less than 10%. When the modification exceeds 30 mol%, it is difficult to adsorb the dichroic dye, which causes a problem that the polarization performance is lowered.

Although the average degree of polymerization of polyvinyl alcohol-type resin is not specifically limited, 100-10000 are preferable, 1500-8000 are more preferable, Furthermore, it is especially preferable that it is 2000-5000. The average degree of polymerization as used herein is also a value obtained by a method determined by JIS K 6726 (1994).

Examples of the polyvinyl alcohol-based resin having such characteristics include PVA124 (saponification degree: 98.0 mol% to 99.0 mol%) of Kuraray Co., Ltd., PVA117 (saulification degree: 98.0 mol% to 99.0 mol%), and PVA624 (saponification degree). : 95.0 mol% to 96.0 mol%) and PVA617 (degree of saponification: 94.5 mol% to 95.5 mol%); For example, AH-26 (saponification degree: 97.0 mol%-98.8 mol%), AH-22 (saponification degree: 97.5 mol%-98.5 mol%) by Nihon Kosei Chemical Co., Ltd., NH-18 (saponification degree: 98.0 mol% to 99.0 mol%), and N-300 (degree of soap: 98.0 mol% to 99.0 mol%); For example, JC-33 (soaping degree: 99.0 mol% or more), JM-33 (soaping degree: 93.5 mol%-95.5 mol%), JM-26 (soaping degree: 95.5 mol%) of Nihon Sakubi Pobaru Co., Ltd. ~ 97.5 mol%), JP-45 (saponification degree: 86.5 mol% to 89.5 mol%), JF-17 (saponification degree: 98.0 mol% to 99.9 mol%), JF-17L (saponification degree: 98.0 mol% to 99.9%) Mol%), JF-20 (saponification degree: 98.0 mol%-99.0 mol%), etc. These can be used suitably in formation of the polyvinyl alcohol-type resin film of this invention.

By forming a polyvinyl alcohol-type resin as mentioned above, a polyvinyl alcohol-type resin film is formed. It does not specifically limit as a film forming method of a polyvinyl alcohol-type resin film. For example, a solvent cast method for coating and drying a polyvinyl alcohol-based resin solution on a support, or a melt extrusion method in which a polyvinyl alcohol-based resin containing water is kneaded and extruded on a support by an extruder, and further, a polyvinyl alcohol-based The gel film-forming method etc. which discharge a resin aqueous solution in a poor solvent (lowly soluble solvent) are mentioned. Among these, since a more transparent film is obtained, the cast method or the melt extrusion method is preferable.

Hereinafter, preferable embodiment of the manufacturing method of a polyvinyl alcohol-type resin film is described. 3 shows a flowchart of a manufacturing method of the polyvinyl alcohol-based resin film of the present embodiment. In this embodiment, the resin layer forming process (S110) which forms the resin layer which consists of polyvinyl alcohol-type resin on a support body, the 1st drying process (S120) which dries this resin layer, and the said resin layer are carried out from the said support body. The resin layer separation process (S130) which peels and acquires the said resin layer, and the 2nd drying process (S140) which dry this resin layer at temperature higher than the temperature in a 1st drying process are normally performed in this order.

As a support body here, a release film, a stainless steel belt, a chill roll is mentioned, for example. As a method of forming the resin layer in a resin layer formation process (S110) on a support body, the above-mentioned solvent casting method and the melt-extrusion method are illustrated. For example, the solvent casting method which forms the polyvinyl alcohol-type resin solution obtained by melt | dissolving the powder of polyvinyl alcohol-type resin in a good solvent (highly soluble solvent) on one surface of a support body, and forms it by evaporating and drying a solvent is suitable. Do. By forming a polyvinyl alcohol-type resin layer in this way, it becomes possible to form the polyvinyl alcohol-type resin layer of 10 micrometers-50 micrometers in thickness.

As a method of coating a polyvinyl alcohol-based resin solution on a support, a roll coating method such as a wire bar coating method, a reverse coating method and a gravure coating method, a die coating method, a comma coater method, a lip coating method, a spin coating method, a screen coating method A well-known method, such as a fountain coating method, the dipping method, and a spray method, can be suitably selected and employ | adopted.

The polyvinyl alcohol-type resin solution used by these methods can be obtained by dissolving polyvinyl alcohol-type resin in the water heated at 80 to 90 degreeC, for example.

The solid content concentration of the polyvinyl alcohol-based resin is preferably in the range of 6 wt% to 50 wt%. When the concentration of the solid content is less than 6 wt%, the viscosity becomes too low and the fluidity at the time of forming the resin layer becomes too high, making it difficult to obtain a uniform film. On the other hand, when the concentration of the solid content exceeds 50 wt%, the viscosity becomes too high and the fluidity at the time of forming the resin layer becomes low, which makes film formation difficult.

A plasticizer can be added to a polyvinyl alcohol-type resin solution. Especially, polyhydric alcohol is used suitably, For example, ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylol propane, etc. are mentioned. You may combine a plurality. In particular, ethylene glycol and glycerin are suitably used. Moreover, if necessary, antiblocking agents, such as surfactant, can also be used together.

After the resin layer forming step (S110), in the first drying step (S120), the resin layer formed on the support is dried to such a degree that the support can be peeled from the support at a low temperature, usually at a drying temperature of 60 ° C. or lower. The extent to which it can peel from a support body is a state in which a coating liquid becomes solid to some extent and can peel as a film. When the moisture content is made to dry to 30 weight% or less normally, the whole film can be peeled stably. It is preferable to dry to 20 wt% or less because it can be more easily peeled off. The moisture content here means the moisture content calculated | required by the dry weight method, and it can obtain | require by the following method.

After leaving PVA film after peeling at room temperature (about 25 degreeC 55% RH) for 30 minutes or more, film weight is measured.

After that, after drying for 60 minutes at 105 degreeC, it takes out, and it is left to stand for several minutes until film temperature returns to normal temperature.

After standing for several minutes, the weight of the film is measured again.

Substituting the obtained values into the following equation.

Moisture content = (weight before drying-weight after drying) / weight before drying x 100 (wt / wt%)

As a specific method of drying the resin layer formed on a support to the extent which can peel from a support body, it is preferable to confirm on the preliminary experiment the drying conditions which reach | attain this peelable state beforehand in actual manufacture, and to carry out on the conditions. For example, it is preferable to dry for 1 to 30 minutes in the temperature range of 40 degreeC-60 degreeC, and drying of 50 degreeC about 3 to 20 minutes is more preferable.

In the first drying step (S120), drying shrinkage in the resin layer is less likely to occur by drying at a low temperature and by drying the resin layer to such an extent that the resin layer can be peeled off from the support. The occurrence of curl at the end can also be prevented.

Next, in the resin layer separation step (S130), the resin layer dried in the first drying step is peeled from the support to obtain a resin layer. And in the 2nd drying process S140, the resin layer peeled from the support body is dried. In the second drying step (S140), the resin layer is sufficiently dried. Therefore, drying is carried out at a high drying temperature as compared with the first drying step. The high temperature here is usually 150 ° C or lower, preferably 120 ° C or lower, more preferably 100 ° C or lower, preferably 60 ° C or higher, and more preferably 70 ° C or higher. Although there exist various methods, such as the method of blowing hot air, the method of making it contact with a hot roll, and the method of heating with an IR heater, a drying method can use all suitably. In addition, the drying temperature used in a 1st drying process and a 2nd drying process means the atmosphere temperature in a drying furnace in the case of the drying installation which installs a drying furnace, such as a method of blowing hot air or an IR heater, and the contact type like a hot roll. In the case of a drying installation, it means the surface temperature of a hot roll. Via the above process, a polyvinyl alcohol-type resin film is manufactured.

The polyvinyl alcohol-type resin film produced by the method of this embodiment becomes a favorable thing in which curl was suppressed.

(Substrate film)

As the resin used for the base film, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, stretchability, and the like is used, and an appropriate resin can be selected according to these glass transition temperatures Tg or melting point Tm. It is preferable to use the base film which can be extended | stretched in the temperature range suitable for extending | stretching the polyvinyl alcohol-type resin film laminated | stacked on it.

Specific examples of the thermoplastic resin include polyolefin resin, polyester resin, cyclic polyolefin resin (norbornene resin), (meth) acrylic resin, cellulose ester resin, polycarbonate resin, polyvinyl alcohol resin and vinyl acetate. Resin, polyarylate resin, polystyrene resin, polyether sulfone resin, polysulfone resin, polyamide resin, polyimide resin, and mixtures and copolymers thereof.

The base film may be a film composed of only one kind of the above-mentioned resin, and may be a film formed by blending two or more kinds of resins. The base film may be a single layer film or a multilayer film.

Examples of the polyolefin-based resin include polyethylene and polypropylene, and it is preferable that the polyolefin-based resin can be stably stretched at a high magnification. Moreover, the propylene ethylene copolymer etc. which are obtained by copolymerizing ethylene with propylene can also be used. Copolymerization may be another kind of monomer, and examples of the monomer of another species copolymerizable with propylene include ethylene and α-olefin. As the? -olefin, an? -olefin having 4 or more carbon atoms is preferably used, and more preferably an? -olefin having 4 to 10 carbon atoms. Specific examples of the α-olefin having 4 to 10 carbon atoms include linear monoolefins such as 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene; Branched monoolefins such as 3-methyl-1-butene, 3-methyl-1-pentene and 4-methyl-1-pentene; Vinylcyclohexane and the like. The copolymer of propylene and other monomer copolymerizable therewith may be a random copolymer or a block copolymer. The content rate of the structural unit derived from this other monomer in a copolymer carries out infrared (IR) spectrum measurement according to the method described on page 616 of the "Polymer Analysis Handbook" (1995, published by Kinokuni Bookstore). Can be obtained by

Of these, propylene homopolymer, propylene-ethylene random copolymer, propylene-1-butene random copolymer, and propylene-ethylene-1-butene random copolymer are preferable as the propylene resin constituting the propylene resin film .

The stereoregularity of the propylene resin constituting the propylene-based resin film is preferably substantially isotactic or syndiotactic. The propylene resin film which consists of propylene resin which has the stereoregularity of isotactic or syndiotactic substantially is relatively good in handleability, and is excellent in mechanical strength in high temperature environment.

Polyester-based resin is a polymer which has an ester bond, and is mainly a polycondensate of polyhydric carboxylic acid and a polyhydric alcohol. As polyhydric carboxylic acid, divalent dicarboxylic acid is mainly used, for example, isophthalic acid, terephthalic acid, dimethyl terephthalate, dimethyl naphthalenedicarboxylic acid, and the like. The polyhydric alcohol to be used is mainly a dihydric diol, and examples thereof include propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. Specific examples of the resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexanedimethanol naphthalate. . These blend resins and copolymers can also be used suitably.

As the cyclic polyolefin-based resin, a norbornene-based resin is preferably used. The cyclic polyolefin resin is a generic term for resins in which cyclic olefins are polymerized as polymerized units, and examples thereof include resins described in JPH01-240517-A, JPH03-14882-A, JPH03-122137-A and the like. Specific examples include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, alpha -olefins such as cyclic olefins, ethylene, and propylene, copolymers thereof (typically random copolymers), and unsaturated carboxylic acids and their Graft polymers modified with derivatives, hydrides thereof, and the like. Specific examples of the cyclic olefin include norbornene monomers.

Various products are commercially available as the cyclic polyolefin resin. Specific examples include Topas (registered trademark) (manufactured by Ticona), Aton (registered trademark) [manufactured by JSR Corporation], ZEONOR (registered trademark) (manufactured by Nihon Xeon Co., Ltd.), ZEONEX (ZEONEX) (Registered trademark) [manufactured by Nihon Xeon Co., Ltd.], Apel (registered trademark) (manufactured by Mitsui Chemical Co., Ltd.), and the like.

As the (meth) acrylic resin, any suitable (meth) acrylic resin may be employed. For example, poly (meth) acrylic acid ester, such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester- (meth ) Acrylic acid copolymer, methyl (meth) acrylate-styrene copolymer (such as MS resin), polymer having alicyclic hydrocarbon group [for example, methyl methacrylate-cyclohexyl copolymer, methyl methacrylate- (meth) acrylic acid Norbornyl copolymer, etc.] etc. are mentioned.

Preferably, poly (meth) acrylate C1-6 alkyl such as poly (meth) acrylate is exemplified. As (meth) acrylic-type resin, More preferably, methyl methacrylate type resin which uses methyl methacrylate as a main component (50 weight%-100 weight%, Preferably 70 weight%-100 weight%) is used.

The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate.

Moreover, these copolymers, the thing which modified one part of hydroxyl groups with the substituent of another species, etc. are mentioned. Of these, cellulose triacetate is particularly preferable. Many products of cellulose triacetate are commercially available and are advantageous in terms of availability and cost. Examples of commercially available products of cellulose triacetate include FujiTak (registered trademark) TD80 (manufactured by FUJIFILM), FujiTak (registered trademark) TD80UF (manufactured by FUJIFILM), FujiTak (registered trademark) TD80UZ [Fujifilm Co., Ltd.], FujiTak (trademark) TD40UZ (manufactured by Fujifilm), KC8UX2M (manufactured by Konica Minolta Opt Co., Ltd.), KC4UY (manufactured by Konica Minolta Opt Co., Ltd.), and the like.

Polycarbonate resin is an engineering plastic which consists of a polymer which the monomeric unit couple | bonded with the carbonate group, and is resin which has high impact resistance, heat resistance, and flame retardance. Moreover, since it has high transparency, it is used suitably also for optical use. As an optical use, resin called the modified polycarbonate which modified the polymer skeleton in order to reduce a photoelastic coefficient, the copolymerized polycarbonate which improved wavelength dependence, etc. is also marketed and can be used suitably. Such polycarbonate resins are widely commercially available, for example, Panlite (registered trademark) [Deijin Kasei Co., Ltd.], Eupyron (registered trademark) [Mitsubishi Engineering Plastics Co., Ltd.], SD Polycar (registered trademark) [Sumitomo Dow Corporation], Caliber (registered trademark) (Dow Chemical Corporation), etc. are mentioned.

In addition to the thermoplastic resin, any appropriate additives may be added to the base film. As such an additive, a ultraviolet absorber, antioxidant, a lubricating agent, a plasticizer, a mold release agent, a coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent, etc. are mentioned, for example. Content of the thermoplastic resin illustrated above in a base film becomes like this. Preferably it is 50 weight%-100 weight%, More preferably, 50 weight%-99 weight%, More preferably, 60 weight%-98 weight%, Especially Preferably it is 70 to 97 weight%. It is because there exists a possibility that the high transparency etc. which a thermoplastic resin originally has may not fully be expressed when content of the thermoplastic resin in a base film is less than 50 weight%.

Although the thickness of the base film before extending | stretching can be suitably determined, Generally, from the point of workability, such as strength and handleability, Preferably it is 1 micrometer-500 micrometers, More preferably, 1 micrometer-300 micrometers, More preferably, 5 micrometers-200 micrometers, particularly preferably 5 micrometers-150 micrometers.

In order to improve adhesiveness with a polyvinyl alcohol-type resin film, a base film may perform a corona treatment, a plasma process, a flame process, etc. on the surface of the side by which a polyvinyl alcohol-type resin film is joined at least. Moreover, in order to improve adhesiveness, you may form thin layers, such as a primer layer, on the side surface in which the polyvinyl alcohol-type resin film of a base film is formed.

(Primer layer)

The primer layer may be formed in the side surface by which the polyvinyl alcohol-type resin film of a base film is bonded. It will not specifically limit, if it is a material which exhibits a strong adhesive force to both a base film and a polyvinyl alcohol-type resin film as a primer layer. For example, thermoplastic resins excellent in transparency, heat stability, and stretchability are used. Specific examples include acrylic resins and polyvinyl alcohol resins, but are not limited thereto. Among them, a polyvinyl alcohol-based resin having good adhesion is preferably used.

As polyvinyl alcohol-type resin used as a primer layer, polyvinyl alcohol resin and its derivative (s) are mentioned, for example. Examples of the derivative of the polyvinyl alcohol resin include polyvinyl formal, polyvinyl acetal, and the like. In addition, polyvinyl alcohol resins may be mixed with unsaturated carboxylic acids such as olefins such as ethylene and propylene, acrylic acid, methacrylic acid and crotonic acid, Or an alkyl ester, acrylamide, or the like. Of the above-mentioned polyvinyl alcohol-based resin materials, polyvinyl alcohol resins are preferably used.

In order to raise the intensity | strength of a primer layer, you may add a crosslinking agent to the said thermoplastic resin. The crosslinking agent added to a thermoplastic resin can use well-known things, such as an organic type and an inorganic type. A more suitable one may be appropriately selected for the thermoplastic resin to be used. For example, in addition to low molecular crosslinking agents such as an epoxy crosslinking agent, an isocyanate crosslinking agent, a dialdehyde crosslinking agent, and a metal chelate crosslinking agent, polymer crosslinking agents such as methylolated melamine resin and polyamide epoxy resin can be used. When a polyvinyl alcohol resin is used as the thermoplastic resin, it is particularly preferable to use a polyamide epoxy resin, methylol melamine, dialdehyde, metal chelate crosslinking agent, or the like as the crosslinking agent.

The thickness of the primer layer is preferably 0.05 µm to 1 µm, more preferably 0.1 µm to 0.4 µm. If it becomes thinner than 0.05 micrometer, the adhesive force of a base film and a polyvinyl alcohol film will fall, and when it becomes thicker than 1 micrometer, it is unpreferable because a polarizing plate becomes thick.

(Pressure-sensitive adhesive layer)

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is also referred to as a pressure-sensitive adhesive, and usually comprises an acrylic resin, a styrene resin, a silicone resin, or the like as a base polymer, to which a crosslinking agent such as an isocyanate compound, an epoxy compound, or an aziridine compound is added. . Moreover, microparticles | fine-particles can be mix | blended in an adhesive and the adhesive layer which shows light scattering property can also be formed.

It is preferable that the thickness of an adhesive layer is 1 micrometer-40 micrometers, but it is preferable to apply | coat thinly in the range which does not impair workability and the characteristic of durability, More preferably, it is 3 micrometers-25 micrometers. If it is 3 micrometers-25 micrometers, it has favorable workability and is a suitable thickness after suppressing the dimensional change of a polarizing film. When the pressure-sensitive adhesive layer is less than 1 m, the pressure-sensitive adhesive property is deteriorated. When the pressure-sensitive adhesive layer is more than 40 m, problems such as the pressure-

The method of forming an adhesive layer on a base film or a polyvinyl alcohol-type resin film is not specifically limited, The solution containing each component containing said base polymer on the base film surface or the polyvinyl alcohol-type resin film surface is carried out. After application | coating and drying to form an adhesive layer, you may bond with a separator or another kind of film, and after forming an adhesive layer on a separator, you may adhere | attach and laminate | stack on the base film surface or the polyvinyl alcohol-type resin film surface. . When the pressure-sensitive adhesive layer is formed on the base film or the polyvinyl alcohol-based resin film surface, if necessary, adhesion treatment such as corona treatment or the like to the base film surface, the polyvinyl alcohol-based resin film surface, or one or both of the pressure-sensitive adhesive layer may be performed. You may carry out.

(Adhesive layer)

As an adhesive agent which comprises an adhesive bond layer, the aqueous adhesive agent using polyvinyl alcohol-type resin aqueous solution, an aqueous two-component urethane emulsion adhesive, etc. are mentioned, for example. Among them, a polyvinyl alcohol-based resin aqueous solution is suitably used. In addition to the vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate which is a homopolymer of vinyl acetate, polyvinyl alcohol-type resin used as an adhesive agent is vinyl alcohol obtained by saponifying the copolymer of vinyl acetate and the other monomer copolymerizable with this. And a modified polyvinyl alcohol-based polymer obtained by partially modifying these hydroxyl groups. As the water-based adhesive, polyaldehyde, a water-soluble epoxy compound, a melamine compound, a zirconia compound, a zinc compound or the like may be added as an additive. When such an aqueous adhesive is used, the adhesive layer obtained next is usually much thinner than 1 micrometer, and even if a cross section is observed with a normal optical microscope, the adhesive bond layer is hardly observed.

The bonding method of the film using the water-based adhesive is not particularly limited, and the adhesive is evenly applied or introduced onto the surface of the base film or the polyvinyl alcohol-based resin film, and the other film is laminated on the coated surface by lamination or the like. And a method of drying. Usually, after preparation, the adhesive agent is apply | coated under the temperature of 15 degreeC-40 degreeC, and joining temperature is the range of 15 degreeC-30 degreeC normally.

When using an aqueous adhesive agent, after bonding a film, it is made to dry in order to remove the water contained in an aqueous adhesive agent. The temperature of the drying furnace is preferably 30 ° C to 90 ° C. If it is less than 30 ° C, the adhesive surface tends to be easily peeled off. If it is 90 degreeC or more, there exists a possibility that optical performances, such as a polarizer, may deteriorate by heat. The drying time may be 10 to 1000 seconds.

After drying, curing may be performed for about 12 to 600 hours at room temperature or a temperature slightly higher than that, for example, at a temperature of about 20 ° C to 45 ° C. The temperature at the time of curing is generally set lower than the temperature employed at the time of drying.

As the non-aqueous adhesive, a photo-curable adhesive may be used. Examples of the photo-curable adhesive include a mixture of a photo-curable epoxy resin and a photo cationic polymerization initiator.

As a method of film bonding with a photocurable adhesive agent, a conventionally well-known method can be used, For example, by the casting method, the Meyer bar coating method, the gravure coating method, the coma coater method, the doctor blade method, the die coating method, the dip coating method, the spraying method, etc. The method of apply | coating an adhesive agent to the adhesive surface of a film, and polymerizing two films is mentioned. The casting method is a method in which two films, which are to be coated, are moved in an approximately vertical direction, an approximately horizontal direction, or in an inclined direction between them, while spreading and spreading an adhesive on a surface thereof.

After apply | coating an adhesive agent on the surface of a film, it adheres by sticking a film through a nip roll etc. in between. Moreover, the method of pressurizing this laminated body with a roll etc. and pressing uniformly can also be used suitably. In this case, metal, rubber, or the like can be used as the material of the roll. Moreover, the method of letting this laminated body pass between a roll and a roll, and pressurizing and spreading is also employ | adopted preferably. In this case, these rolls may be made of the same material or different materials. The thickness of the adhesive layer after bonding using the nip roll or the like before drying or curing is preferably 5 m or less and 0.01 m or more.

The adhesive surface of the film may be appropriately subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet ray irradiation treatment, frame (flame) treatment, saponification treatment, etc., in order to improve the adhesiveness.

As a saponification process, the method of immersing in aqueous alkali solution, such as sodium hydroxide and potassium hydroxide, is mentioned.

When using photocurable resin as an adhesive agent, after laminating | stacking a film, a photocurable adhesive agent is hardened by irradiating an active energy ray. Although the light source of an active energy ray is not specifically limited, The active energy ray which has a luminescence distribution in wavelength 400nm or less is preferable, Specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a micro Wave-excited mercury lamps, metal halide lamps and the like are preferably used.

Light irradiation intensity to a photocurable adhesive agent is suitably determined by the composition of a photocurable adhesive agent, Although it does not specifically limit, The irradiation intensity of the wavelength range effective for activation of a polymerization initiator is 0.1 mW / cm <2> -6000 mW / cm <2>. desirable. When the irradiation intensity is not less than 0.1 mW / cm 2, the reaction time is not excessively long, and when the irradiation intensity is 6000 mW / cm 2 or less, the heat radiated from the light source and the heat generated upon curing of the photo- Is less likely to occur. Although light irradiation time to a photocurable adhesive agent is applied with the photocurable adhesive agent to harden, it does not specifically limit, but the accumulated light quantity expressed as a product of said irradiation intensity and irradiation time is 10 mJ / cm <2> -10000 mJ / cm <2> It is preferable to set so that. When the total amount of light to the photo-curing adhesive is 10 mJ / cm 2 or more, a sufficient amount of active species originating from the polymerization initiator is generated sufficiently to allow the curing reaction to proceed more surely. When the amount is 10,000 mJ / cm 2 or less, , And good productivity can be maintained. Moreover, the thickness of the adhesive bond layer after active energy ray irradiation is about 0.001 micrometer-5 micrometers normally, Preferably they are 0.01 micrometer or more and 2 micrometers or less, More preferably, they are 0.01 micrometer or more and 1 micrometer or less.

In the case where the photocurable adhesive on the base film or the polyvinyl alcohol-based resin film is cured by irradiation of active energy rays, conditions in which various functions of the polarizing plate after passing through the whole process, such as transmittance, color, and transparency of these films, do not deteriorate It is preferable to perform hardening.

&Lt; Stretching step (S20)

Here, the laminated | multilayer film which consists of a base film and a polyvinyl alcohol-type resin film is uniaxially stretched. Preferably, uniaxial stretching is performed so that the stretching magnification is 5 times to 17 times or less. More preferably not more than 5 times but not more than 8 times. If the draw ratio is 5 times or less, the polyvinyl alcohol-based resin film is not sufficiently oriented, and as a result, there may be a problem that the polarization degree of the polarizer layer does not sufficiently increase. On the other hand, when a draw ratio exceeds 17 times, breakage of the laminated | multilayer film at the time of extending | stretching tends to occur, and there exists a possibility that workability and handling property in a subsequent process may fall. The extending | stretching process in extending process S20 is not limited to extending | stretching in one end, but can also be performed in multiple steps. When performing in multiple stages, it is preferable to perform an extending | stretching process so that the whole stage of an extending | stretching process may be combined and it may become a draw ratio more than 5 times.

In the extending process (S20) in this invention, the longitudinal stretch process performed with respect to the longitudinal direction of a laminated | multilayer film, the horizontal stretch process extended with respect to the width direction, etc. can be performed. Examples of the longitudinal stretching method include an inter-roll stretching method and a compression stretching method, and the transverse stretching method includes a tenter method and the like.

&Lt; Dyeing process (S30) >

Here, the resin layer of a laminated film is dyed with a dichroic dye. Examples of the dichroic dyes include iodine and organic dyes. Examples of the organic dyes include 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 Sky Blue, Direct First Orange S, first black, etc. can be used. One type of these dichroic substances may be sufficient, and they may be used in combination of 2 or more types.

A dyeing process is performed by immersing the whole stretched film in the aqueous solution (dyeing solution) containing a dichroic dye, for example. As the dyeing solution, a solution obtained by dissolving the dichroic dye in a solvent can be used. As the solvent of the dyeing solution, water is generally used, but an organic solvent having compatibility with water may be further added. It is preferable that the density | concentration of a dichroic dye is 0.01 weight%-10 weight%, It is more preferable that it is 0.02 weight%-7 weight%, It is especially preferable that it is 0.025 weight%-5 weight%.

When iodine is used as the dichroic dye, it is preferable to further add iodide because the dyeing efficiency can be further improved. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide. It is preferable that the addition ratio of these iodide is 0.01 weight%-20 weight% in a dyeing solution. Among 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 1: 6 to 1:80, more preferably 1: 7 to 1: 70.

The immersing time of the stretched film in the dyeing solution is not particularly limited, but is preferably in the range of usually 15 seconds to 15 minutes, more preferably 1 to 3 minutes. The temperature of the dyeing solution is preferably in the range of 10 캜 to 60 캜, more preferably in the range of 20 캜 to 40 캜.

<Crosslinking process>

The dyeing step may be followed by a crosslinking treatment. Crosslinking process is performed by immersing a stretched film in the solution (crosslinking solution) containing a crosslinking agent, for example. As a crosslinking agent, a conventionally well-known substance can be used. Boron compounds such as boric acid and borax, and glyoxal and glutaraldehyde. These may be one type, or two or more types may be used in combination.

As the crosslinking solution, a solution in which a crosslinking agent is dissolved in a solvent can be used. As the solvent, for example, water may be used, but an organic solvent which is compatible with water may also be contained. Although the density | concentration of the crosslinking agent in a bridge | crosslinking solution is not limited to this, It is preferable to exist in the range of 1 weight%-20 weight%, and it is more preferable that it is 6 weight%-15 weight%.

Iodide may be added to the crosslinking solution. By adding iodide, the polarization characteristics in the plane of the resin layer can be made more uniform. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide. Content of iodide is 0.05 weight%-15 weight%, More preferably, they are 0.5 weight%-8 weight%.

The immersion time of the laminated film in the crosslinking solution is preferably 15 seconds to 20 minutes, more preferably 30 seconds to 15 minutes. The temperature of the cross-linking solution is preferably in the range of 10 占 폚 to 80 占 폚.

<Cleaning step>

It is preferable to perform a washing | cleaning process after a crosslinking process. As the washing step, a water washing treatment can be carried out. Water washing treatment can be normally performed by immersing a laminated film in pure water, such as ion-exchange water and distilled water. The water washing temperature is usually 3 ° C to 50 ° C, preferably 4 ° C to 20 ° C. The immersion time is usually from 2 to 300 seconds, preferably from 3 seconds to 240 seconds.

The washing process may combine the washing | cleaning process with an iodide solution, and the water washing process, and the solution which mix | blended liquid alcohol, such as methanol, ethanol, isopropyl alcohol, butanol, a propanol, can also be used suitably.

<Drying step>

After the washing step, a drying step may be performed. As a drying process, arbitrary suitable methods (for example, natural drying, ventilation drying, heat drying) can be employ | adopted. For example, in the case of heat drying, the drying temperature is usually 20 ° C to 95 ° C, and the drying time is usually about 1 to 15 minutes.

Via the above process, a polyvinyl alcohol-type resin film has a function as a polarizer layer, and the polarizing laminated film provided with the polarizer layer in one side of a base film is manufactured.

(Polarizer layer)

Specifically, the polarizer layer adsorbs and aligns the dichroic dye to the uniaxially stretched polyvinyl alcohol-based resin film. The draw ratio is preferably more than 5 times, more preferably more than 5 times and 17 times or less.

The thickness of the polarizer layer (thickness of the polyvinyl alcohol-based resin film after stretching) is preferably 25 µm or less, more preferably 20 µm or less, and preferably 2 µm or more. By making thickness of a polarizer layer into 25 micrometers or less, a thin polarizing laminated film can be comprised.

<Protective film bonding step (S40)>

A protective film is bonded to the surface on the opposite side to the surface on the base film side of the polarizer layer in the polarizing laminated film. The bonding method of a polarizer layer and a protective film is not specifically limited. For example, an adhesive layer or an adhesive bond layer is formed in the bonding surface of a polarizer layer and / or a protective film, and both are bonded together through an adhesive layer or an adhesive bond layer. The material suitable as an adhesive layer or an adhesive bond layer is similar to the adhesive layer and adhesive bond layer stated in the column of the above-mentioned resin film bonding process (S10).

(Protective film)

A protective film may be a simple protective film which does not have an optical function, and may be a protective film which also has optical functions, such as a retardation film and a brightness improving film.

Although it does not specifically limit as a material of a protective film, For example, cellulose acetate-based resin film containing resins, such as a cyclic polyolefin type resin film, triacetyl cellulose, and diacetyl cellulose, polyethylene terephthalate, polyethylene naphthalate, and polybutylene tere The film which is widely used conventionally in the art, such as a polyester resin film containing a resin like phthalate, a polycarbonate resin film, an acrylic resin film, and a polypropylene resin film, is mentioned.

As cyclic polyolefin type resin, a suitable commercial item, for example, Topas (trademark) (made by Ticona), Aton (trademark) (manufactured by JSR Corporation), ZEONOR (registered trademark) [manufactured by Nihon Xeon Co., Ltd.] ], ZEONEX (manufactured by Nippon Zeon Co., Ltd.), Apel (registered trademark) (manufactured by Mitsui Chemical Co., Ltd.), and the like can be suitably used. When forming such a cyclic polyolefin type resin into a film, well-known methods, such as the solvent casting method and the melt-extrusion method, are used suitably. In addition, such as Esshina (registered trademark) (manufactured by Sekisuga Chemical Co., Ltd.), SCA40 (manufactured by Sekisuga Chemical Co., Ltd.), and Zeonoa (registered trademark) film (manufactured by OPTES) You may use the commercial item of the film made of cyclic polyolefin type resin previously formed into a film.

The cyclic polyolefin-based resin film may be uniaxially stretched or biaxially stretched. By stretching, an arbitrary retardation value can be imparted to the cyclic polyolefin-based resin film. Stretching is normally performed continuously while unwinding a film roll, and it extends | stretches to the advancing direction of the roll, the advancing direction and the perpendicular direction, or both in a heating furnace. The temperature of a heating furnace is the range from the glass transition temperature vicinity of cyclic polyolefin type resin to glass transition temperature +100 degreeC normally. The magnification of the stretching is usually 1.1 to 6 times, preferably 1.1 to 3.5 times, in one direction.

Since the cyclic polyolefin resin film is generally inferior in surface activity, it is preferable to perform surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, frame (flame) treatment, saponification treatment, etc. on the surface to be bonded to the polarizer layer. Do. Especially, the plasma process and corona treatment which can be implemented comparatively easily are suitable.

As a cellulose acetate type resin film, a suitable commercial item, for example, FujiTak (trademark) TD80 (manufactured by FUJIFILM Corporation), FujiTak (trademark) TD80UF (manufactured by Fujifilm), FujiTak (registered trademark) TD80UZ Fuji Film Co., Ltd., FujiTak TD40UZ (Fuji Film Co., Ltd.), KC8UX2M (Konica Minolta Opt Co., Ltd.), KC4UY (Konica Minolta Opt Co., Ltd.), etc. suitably It is available.

A liquid crystal layer or the like may be formed on the surface of the cellulose acetate-based resin film in order to improve the viewing angle characteristics. Further, in order to impart a phase difference, a cellulose acetate-based resin film may be stretched. The cellulose acetate-based resin film is usually subjected to saponification treatment in order to improve the adhesion with the polarizing film. As a saponification process, the method of immersing in aqueous solution of alkalis, such as sodium hydroxide and potassium hydroxide, can be employ | adopted.

On the surface of the protective film as described above, an optical layer such as a hard coat layer, an antiglare layer, and an antireflection layer may be formed. The method of forming these optical layers on the protective film surface is not specifically limited, A well-known method can be used.

The thickness of the protective film is preferably as thin as possible from the requirement for thinning, preferably 90 m or less, more preferably 50 m or less. On the contrary, when too thin, strength falls and it is inferior to workability, It is preferable that it is 5 micrometers or more.

<Base film peeling process (S50)>

In the manufacturing method of the polarizing plate of this embodiment, as shown in FIG. 2, a base film peeling process (S50) is performed after the protective film bonding process (S40) which bonds a protective film to a polarizer layer. In a base film peeling process (S50), a base film is peeled from a polarizing laminated film. The peeling method of a base film is not specifically limited, The method similar to the peeling process of the peeling film performed by the polarizing plate which has a normal adhesive can be employ | adopted. After protective film bonding process (S40), it may peel immediately as it is, and after winding up once in roll shape, you may provide and separate peeling process separately. Via the above process, the polarizing plate provided with the protective film in one surface of the polarizer layer is manufactured.

(Another optical layer)

The polarizing plate can be used as a polarizing plate in which other optical layers are laminated in practice.

Moreover, the said protective film may have a function of these optical layers.

Examples of another optical layer include a reflective polarizing film that transmits polarized light of some kind and reflects polarized light exhibiting properties opposite thereto, a film having an antiglare function having irregularities on its surface, and a surface antireflection function. The film, the reflective film which has a reflection function on the surface, the semi-transmissive reflective film which has a reflection function, and a transmission function, a viewing angle compensation film, etc. are mentioned.

As a commercial item corresponding to the reflection type polarizing film which permeate | transmits some kind of polarized light and reflects the polarized light which shows the opposite property, it is DBEF [it can be obtained from 3M Corporation, Sumitomos Reem Co., Ltd.], APF, for example. [Available from 3M Co., Ltd., available from Sumitomos Reem Co., Ltd.]. As a viewing angle compensation film, the liquid crystal compound is apply | coated to the surface of a base material, the optical compensation film orientated, the retardation film which consists of polycarbonate resin, the retardation film which consists of cyclic polyolefin resin, etc. are mentioned. As a commercial item corresponded to the optical compensation film in which the liquid crystalline compound is apply | coated on the surface of a base material, and is oriented, WV film [Fuji Film Co., Ltd. product], NH film [Shin-Nihon Sekiyu Co., Ltd. product], NR film [New] Nippon Sekiyu Co., Ltd.] etc. are mentioned. Moreover, as a commercial item corresponded to the retardation film which consists of cyclic polyolefin resin, Aton (trademark) film [made by JSR Corporation], Esshina (registered trademark) [manufactured by Sekisui Chemical Co., Ltd.], Zeonoa (Trademark) Film [made by OPTES Corporation] etc. are mentioned.

[Example]

[Example 1]

<Production of Polyvinyl Alcohol-Based Resin Film>

The powder of the fully saponified polyvinyl alcohol resin (trade name: PVA124) sold by Kuraray Co., Ltd. was dissolved in hot water at 90 ° C. to prepare a polyvinyl alcohol resin aqueous solution having a solid content of 10 wt%. The obtained polyvinyl alcohol resin aqueous solution was apply | coated to about 400 micrometer thickness by the lip coat method on the PET base material on which the mold release process was performed. After drying at 50 ° C for 10 minutes, the polyvinyl alcohol-based resin film was peeled off from the PET substrate and further dried at 80 ° C for 5 minutes to obtain a polyvinyl alcohol-based resin film without curls. The thickness after drying was 41 μm.

<Resin film bonding process>

The polyvinyl alcohol powder and the crosslinking agent were dissolved in hot water to prepare an aqueous adhesive solution having the following composition. And the corona discharge process is given to the 110-micrometer-thick base film which consists of polypropylene resin (brand name: FLX80E4, the Sumitomo Chemical Co., Ltd. make), and the thickness after drying the above-mentioned adhesive aqueous solution using a gravure coater is 0.2 micrometer. The coating was applied to a degree. Then, after bonding the above-mentioned polyvinyl alcohol-type resin film, it dried at 50 degreeC for 3 minutes, and obtained the laminated | multilayer film. The obtained laminated | multilayer film was flat and handling was easy.

(Adhesive Aqueous Solution)

Water: 100 parts by weight, polyvinyl alcohol resin powder (manufactured by Kuraray Co., Ltd., average polymerization degree 18000, trade name: KL-318): 3 parts by weight, polyamide epoxy resin [crosslinking agent, manufactured by Sumica Chemtex Co., Ltd. : SR650 (30)]: 1.5 parts by weight.

<Stretching Step>

The laminated film was subjected to 5.8 times free end uniaxial stretching at 160 ° C. using a tenter apparatus. The thickness of the polyvinyl alcohol-type resin film after extending | stretching was 18 micrometers.

<Dyeing Process>

Thereafter, the laminated film was immersed in a dye solution at 30 ° C. which is a mixed aqueous solution of iodine and potassium iodide for 180 seconds to dye a polyvinyl alcohol-based resin film, and then the excess iodine solution was washed with 10 ° C. pure water. Subsequently, it was immersed for 300 second in the bridge | crosslinking solution which is a mixed aqueous solution of 76 degreeC boric acid and potassium iodide. Thereafter, the resultant was washed with pure water at 10 ° C. for 4 seconds, and finally, excess water on the surface was removed with a nip roll. The compounding ratio of the chemical liquid of each layer is as follows. The laminated film after dyeing was dried at 80 degreeC for 5 minutes, and the polarizing laminated film was obtained.

(Dyeing solution)

100 parts by weight of water, 0.6 parts by weight of iodine, and 10 parts by weight of potassium iodide.

(Crosslinking solution)

Water: 100 parts by weight, boric acid: 9.5 parts by weight, potassium iodide: 5 parts by weight.

<Protective film bonding process>

The adhesive aqueous solution like the resin film bonding process was prepared. After apply | coating the adhesive agent solution mentioned above to the surface on the opposite side to the surface of the polarizer layer of the said polarizing layer film, the protective film [TAC: KC4UY of Konica Minolta Opto Co., Ltd. product] is bonded, and a base film, The polarizing plate containing five layers of an adhesive bond layer, a polarizer layer, an adhesive bond layer, and a protective film was obtained.

<Base film peeling process>

The polarizing plate mentioned above was dried at 80 degreeC for 5 minutes, and the polarizing plate was obtained. The base film was peeled from the obtained polarizing plate. The base film peeled easily, and obtained the polarizing plate containing four layers of an adhesive bond layer, a polarizer layer, an adhesive bond layer, and a protective film. The thickness of the polarizer layer was 18 micrometers. The polarization performance of the obtained polarizing plate was measured with the spectrophotometer (V7100) of the Nippon Bunco Corporation. The incident direction of light was from the polarizer layer side. The visibility correction | amendment single transmittance was 41.8%, and the visibility correction polarization degree was 99.997%, and it was very excellent in polarization performance, and it was the performance which can fully be used as a polarizing plate.

[Comparative Example 1]

After performing corona discharge treatment on the same base film as Example 1, the polyvinyl alcohol resin aqueous solution used for preparation of the polyvinyl alcohol-type resin film in Example 1 was apply | coated directly by the gap coat method. Thereafter, drying was performed continuously at 50 ° C. for 10 minutes and at 80 ° C. for 5 minutes, but remarkable curl occurred due to the drying shrinkage of the polyvinyl alcohol resin layer, and folding of the end portion at the outlet of the drying furnace occurred. . The thickness after drying of the obtained polyvinyl alcohol resin layer was about 39 micrometers.

Claims (5)

A resin film bonding step of bonding a resin film made of polyvinyl alcohol-based resin having a thickness of 50 μm or less to one side of the base film to obtain a laminated film,
A stretching step of uniaxially stretching the laminated film,
A polarizing layer comprising a base film and a polarizer layer formed on one side of the base film, including a dyeing step of sequentially dyeing the resin film of the uniaxially-stretched laminated film with a dichroic dye to form a polarizer layer. Method for producing a film. The said resin film bonding process WHEREIN: The manufacturing method of Claim 1 which bonds the said resin film to one side of the said base film through an adhesive layer or an adhesive bond layer. The manufacturing method of Claim 1 or 2 whose thickness of the said resin film is 15 micrometers or more in the said resin film bonding process. The said resin film as described in any one of Claims 1-3 in the said resin film bonding process,
A resin layer forming step of forming a resin layer made of polyvinyl alcohol-based resin on a support;
A first drying step of drying the resin layer formed on the support;
A resin layer separation step of peeling a dried resin layer from the support to obtain the resin layer;
The manufacturing method which is a resin film manufactured by the method containing the 2nd drying process which dries the peeled resin layer at the drying temperature higher than the temperature in the said 1st drying process in this order. After manufacturing a polarizing laminated film by the manufacturing method of Claim 1,
The protective film bonding process of bonding a protective film to the surface on the opposite side to the surface of the said polarizer layer of the said polarizing layer in the said polarizing laminated film,
The manufacturing method of the polarizing plate provided with the polarizer layer and the protective film formed in one surface of the said polarizer layer including the base film peeling process which peels the said base film from the said polarizing laminated film in this order.

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