JP2002267839A - Polarizing film, polarizing film with wide viewing angle and tacky film of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing film (with a wide viewing angle) which is excellent in the adhesion property with a glass substrate of a liquid crystal panel and preferable easy peeling property and which leaves no glue when the films are exchanged. SOLUTION: The polarizing film has a protective layer containing cellulose triacetate as the main material on at least one surface of a polarizer and the surface of the cellulose triacetate layer is used as the sticking surface to the glass substrate of a liquid crystal panel. In this film, the contact angle of the surface of the cellulose triacetate with water is specified to <=50 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing film and a wide viewing angle polarizing film. Furthermore, the present invention relates to these polarizing films and these adhesive films in which an adhesive layer is provided on a wide viewing angle polarizing film. These adhesive forms form a liquid crystal display device attached to at least one side of the liquid crystal panel.

[0002]

2. Description of the Related Art A liquid crystal display (hereinafter, referred to as LCD) has an image display section (liquid crystal panel) called a cell in which liquid crystal molecules are sealed. A liquid crystal panel is provided with a glass substrate sealed with a sealant on both sides to enclose the liquid crystal molecules and the liquid crystal molecules, and changes the light transmittance by changing the geometrical arrangement of the liquid crystal molecules. Display. However, since an image cannot be displayed by this alone, a polarizing film is attached to both sides of the liquid crystal panel to control light. The polarizing film is composed of a polarizer that polarizes light and a polarizer protective layer on both sides thereof.In general, as a polarizer, iodine or a dichroic dye is adsorbed on a hydrophilic polymer such as polyvinyl alcohol. A cellulose polymer film such as a cellulose triacetate film has been awarded as the protective layer.

[0003] In addition to a polarizing film, various optical elements have been used on the surface of a liquid crystal panel in order to improve the display quality of an LCD. For example, a wide viewing angle polarizing film in which an optical compensation film is laminated on a polarizing film is used in order to achieve a liquid crystal display device having a good viewing angle and a wide viewing angle with little in-plane luminance unevenness. The optical compensation film also functions as a protective layer of the polarizer, for example, a liquid crystal layer is formed by applying a material having liquid crystallinity to a support film such as a cellulose triacetate film. It is formed of a discotic liquid crystal having a tilted orientation, a nematic liquid crystal having a tilted orientation, or the like.

The above-mentioned polarizing film or wide viewing angle polarizing film (hereinafter, also referred to as (wide viewing angle) polarizing film) is attached to a liquid crystal panel by a protective layer of the (wide viewing angle) polarizing film and a liquid crystal panel. A glass substrate can be attached via an adhesive. In addition, the (wide viewing angle) polarizing film can be instantly fixed to the outermost surface of the liquid crystal panel, and the (wide viewing angle) polarizing film does not require a drying step to be fixed. Viewing angle)
The polarizing film has an adhesive layer on the protective layer (wide viewing angle)
Used as a polarizing adhesive film.

[0005] The above-mentioned pressure-sensitive adhesives have some required performances. One example is heating and humidification (wide viewing angle).
The polarizing film is not peeled off partially, and the adhesive stability is improved. In addition, when bonding a (wide viewing angle) polarizing film to a liquid crystal panel, the pressure-sensitive adhesive may be displaced in a bonding position or a foreign substance may be mixed into a bonding surface, resulting in a (wide viewing angle) polarizing film-derived defect. In such a case, it is required that the (wide-viewing angle) polarizing film be peeled off from the outermost surface of the liquid crystal panel, and that the film be easily peeled off again. This replacement work has not been regarded as a problem for conventional small liquid crystal panels, but in recent years, as the size of liquid crystal panels has increased, the replacement work rate has increased. Has become an important issue. In particular, when the adhesive of the polarizing film (wide viewing angle) is transferred to the liquid crystal panel at the time of peeling and there is a so-called glue residue, the replacement operation becomes a large load. However, the adhesion stability and the peeling easiness are contradictory performances, and the performances of both are not sufficiently satisfied.

[0006]

SUMMARY OF THE INVENTION The present invention provides a polarizing film which has excellent adhesion to a glass substrate of a liquid crystal panel, has good peeling simplicity, and has no adhesive residue when replaced (wide viewing angle). The purpose is to do. Also (wide viewing angle)
It is an object of the present invention to provide these adhesive films in which an adhesive layer is provided on a polarizing film, and further to provide a liquid crystal display device in which the (wide viewing angle) polarizing adhesive film is attached to at least one side of a liquid crystal panel. And

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and have achieved the above object by using the following materials as a protective layer of a (wide viewing angle) polarizing film. They have found that they can do this and have completed the present invention.

That is, the present invention provides a polarizer having a protective layer based on cellulose triacetate on at least one surface thereof.
In addition, the present invention relates to a polarizing film, wherein the cellulose triacetate surface has a contact angle with water of 50 ° or less in the polarizing film in which the surface of the cellulose triacetate is to be attached to a glass substrate of a liquid crystal panel.

The polarizing film of the present invention is one of cellulose triacetate, which has been awarded as a transparent base material for forming a protective layer of a polarizer, among water on the surface of the protective layer, which is the surface to which a glass substrate of a liquid crystal panel is adhered. Have a contact angle of not more than 50 ° with good adhesion to the pressure-sensitive adhesive layer provided on the surface of the protective layer. As mentioned above, the contact angle is 5
On the surface of the protective layer of the polarizing film having a temperature of 0 ° or less, the adhesive strength between the adhesive layer and the adhesive layer is improved.
Is smaller than the adhesive strength (2) of the protective layer (cellulose triacetate), so that when the polarizing film is separated from the liquid crystal panel, the separation on the liquid crystal panel side can be prioritized. Such a polarizing film has good peeling simplicity and good removability, and the adhesive is transferred to the liquid crystal panel, so that there is little so-called glue residue, and the peeling simplicity is good even in the case of a large liquid crystal panel. . The contact angle of the surface of the protective layer with water is more preferably 40 ° or less.

In the above polarizing film, it is preferable that cellulose triacetate is saponified.
The cellulose triacetate forming the protective layer having a contact angle with water of 50 ° or less can be obtained, for example, by reducing the contact angle by saponifying cellulose triacetate and modifying the surface.

In the above polarizing film, it is preferable that the adhesion angle of cellulose triacetate is lower than that before saponification treatment by 10 ° or more.

[0012] The contact angle with water is reduced by 5% or more by reducing the adhesion angle of cellulose triacetate by 10 ° or more by saponification treatment.
When the angle is set to 0 ° or less, the surface is sufficiently modified, and the protective layer surface has a large improvement in the adhesive force with the adhesive layer. From this viewpoint, it is more preferable that the saponification treatment reduces the adhesion angle of cellulose triacetate by 20 ° or more.

Further, the present invention provides a wide viewing angle polarizing film having an optical compensation film as a protective layer on at least one surface of a polarizer, wherein the surface of the optical compensation film serves as a glass substrate bonding surface of a liquid crystal panel. A wide viewing angle polarizing film, wherein the optical compensation film has a contact angle with water of 75 ° or less.

The wide viewing angle polarizing film of the present invention uses an optical compensation film as a protective layer of a polarizer.
It has been found that those having a contact angle with water of 75 ° or less on the surface of the optical compensation film serving as the bonding surface of the glass substrate of the liquid crystal panel have good adhesive strength with the adhesive layer provided on the protective layer surface. Things. The optical compensation film surface of the wide viewing angle polarizing film having a contact angle of 75 ° or less as described above,
As a result of the improvement of the adhesive strength with the adhesive layer, the adhesive strength of the adhesive layer with respect to glass (1) is made smaller than the adhesive strength of the optical compensation film with respect to the optical compensation film (2), and the wide viewing angle polarizing film is peeled from the liquid crystal panel. In this case, adjustment can be made so that the separation on the liquid crystal panel side can be given priority. Such a wide-field polarizing film has good peeling simplicity and good removability, and the adhesive is transferred to the liquid crystal panel, so-called little glue residue, and the peeling simplicity is good even for a large liquid crystal panel. It is. The contact angle of the optical compensation film surface with water is more preferably 73 ° or less.

In the wide viewing angle polarizing film, it is preferable that the optical compensation film has been saponified. The optical compensation film having a contact angle with water of 75 ° or less can be obtained by reducing the contact angle by saponifying the optical compensation film and modifying the surface.

In the wide viewing angle polarizing film, it is preferable that the adhesion angle of the optical compensation film is lower by 3 ° or more than before the saponification treatment.

By lowering the adhesion angle of the optical compensation film by 3 ° or more by saponification treatment, the contact angle with water can be reduced to 75 °.
° or less, the surface modification is sufficiently made,
The surface of the optical compensation film has a large improvement in adhesive strength with the adhesive layer. From this viewpoint, it is more preferable that the angle of adhesion of the optical compensation film is reduced by 5 ° or more by the saponification treatment.

Since the surface of the optical compensation film has a stronger repulsion against water than cellulose triacetate, the contact angle of the wide viewing angle polarizing film with water is higher than that of the polarizing film. The above effect is also exhibited, and the above effect is exhibited even when the saponification treatment has a large modifying effect and the decrease in the adhesion angle due to the saponification treatment is small. The lower limit of the adhesion angle of the cellulose triacetate and the optical compensation film is not particularly limited.
It is preferable that the angle be equal to or greater than °.

In one preferred embodiment of the wide viewing angle polarizing film, the optical compensation film is an optical compensation film having a support film and an optically anisotropic layer made of a material exhibiting liquid crystallinity.

The polarizing film laminated with such an optical compensatory film is a wide viewing angle polarizing film, which achieves a wide viewing angle with good visibility and is effective in forming a liquid crystal display device with less in-plane luminance unevenness. It is.

Further, the present invention relates to a polarizing adhesive film, wherein an adhesive layer is provided on the surface of the polarizing film to which the glass substrate is adhered on the protective layer surface.

Furthermore, the present invention relates to a wide-viewing-angle polarizing adhesive film, wherein an adhesive layer is provided on the surface of the optical compensation film of the wide-viewing-angle polarizing film. The polarizing pressure-sensitive adhesive film having a pressure-sensitive adhesive layer (wide field of view) provided on the surface of the protective layer on which the glass substrate is adhered has an adhesive force (1) with respect to glass and an adhesive force with respect to the protective layer (cellulose triacetate or optical compensation film). Those adjusted to be smaller than (2) have good peeling simplicity and have no adhesive residue.

The adhesive strength (1) of the pressure-sensitive adhesive layer to glass preferably has a value of 0.1 to 20 N / 25 mm, and has good adhesiveness to a glass substrate. The adhesive strength (1) is preferably in a range of 1 to 15 N / 25 mm. In the (wide-view) polarized pressure-sensitive adhesive film,
It is preferable that the ratio of the adhesive strength (1) of the glass to the adhesive strength (2) of the protective layer: adhesive strength (2) / adhesive strength (1) is 1 or more. Further, when the ratio (adhesive force (2) / adhesive force (1)) is 1.3 or more, peeling simplicity is good, and there is no adhesive residue, which is more preferable.

Further, the present invention relates to a liquid crystal display device wherein the polarizing adhesive film or the wide-viewing-angle polarizing adhesive film is adhered to at least one side of a liquid crystal panel.

The liquid crystal display device to which the polarizing pressure-sensitive adhesive film has been adhered has excellent adhesiveness to a glass substrate, and has good peeling convenience.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, a polarizing film of the present invention comprises a polarizer 1 and a protective layer 2 made of cellulose triacetate having the above-mentioned contact angle laminated on at least one surface. The layer 2 may be provided with an adhesive layer 4 for attaching a glass substrate of a liquid crystal panel to form a polarizing adhesive film. Further, a release sheet 5 can be provided on the adhesive layer 4. The lamination of the polarizer 1 and the protective layer 2 is performed with an adhesive or the like.

The polarizer 1 is not particularly limited, and various types can be used. Examples of the polarizer include dichroic dyes such as iodine and dichroic dyes on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene-vinyl acetate copolymer-based partially saponified film. Examples thereof include a film obtained by adsorbing a substance and stretched, and a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrochlorinated product of polyvinyl chloride. Although the thickness of the polarizer is not particularly limited,
The thickness is generally about 5 to 80 μm. Among these, those obtained by stretching a polyvinyl alcohol-based film and adsorbing and orienting a dichroic material (iodine, dye) are preferably used.

At least one surface of the polarizer 1 is provided with two protective layers based on cellulose triacetate.
The surface of the protective layer 2 becomes the glass substrate attachment surface of the liquid crystal panel. In the present invention, as the cellulose triacetate base material for forming the protective layer, a base material having a contact angle of the glass substrate attachment surface adjusted to 50 ° or less is used. In the present invention, a cellulose triacetate base material is saponified, and a material whose adhesion angle is lower than that before saponification treatment by 10 ° or more is used as a protective layer. The saponification treatment uses a saponification treatment solution such as an aqueous alkali hydroxide solution having a concentration of 5 to 20% by weight. As the alkali hydroxide, sodium hydroxide or the like can be used, and the saponification temperature is preferably about 25 to 80 ° C. The thickness of the cellulose triacetate substrate serving as the protective layer is not particularly limited, but is generally about 20 to 120 μm.

As shown in FIG. 2, the wide viewing angle polarizing film of the present invention is obtained by laminating an optical compensation film 3 having the above-mentioned contact angle on at least one surface of a polarizer 1 as a protective layer. 3 is provided with an adhesive layer 4 for attaching a glass substrate of a liquid crystal panel to form a wide-viewing-angle polarizing adhesive film. Further, a release sheet 4 can be provided on the adhesive layer 4. The lamination of the polarizer 1 and the optical compensation film 3 is performed with an adhesive or the like.

As the optical compensation film 3, for example,
Examples include a birefringent film obtained by uniaxially or biaxially stretching a polymer film, and a liquid crystal alignment film having an optically anisotropic layer made of a liquid crystal material exhibiting birefringence on a support film. Although the thickness of the optical compensation film 3 is not particularly limited, it is generally about 5 to 100 μm.

Among these optical compensation films 3, FIG.
As shown in FIG. 3, the optically anisotropic layer 3 is formed on the support film 3a.
The liquid crystal alignment film having b is preferred. In FIG. 2, the optical compensation film, the polarizer 1 on the support film 3a side,
Although the adhesive layer 4 is laminated on the optically anisotropic layer 3b side, the laminating direction is not particularly limited.

Examples of the polymer material for forming the birefringent film include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose,
Hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate,
Polyether sulfone, polyphenylene sulfide,
Polyphenylene oxide, polyallyl sulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulosic polymer, or binary, ternary copolymers, graft copolymers, blends thereof, etc. Can be These polymer materials become oriented products (stretched films) by stretching or the like.

The support film 3a is formed of a transparent polymer, and an appropriate transparent material can be used. However, a material having excellent transparency, mechanical strength, heat stability, moisture barrier property, etc. is preferably used. The thickness of the support film 3a is not particularly limited, but is generally about 5 to 50 μm. Examples of the transparent polymer forming the support film include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as cellulose diacetate and cellulose triacetate, acrylic polymers such as polymethyl methacrylate, polystyrene and acrylonitrile. Styrene-based polymers such as a styrene copolymer (AS resin), polycarbonate-based polymers, and the like. Also, polyethylene, polypropylene,
Polyolefin having a cyclo- or norbornene structure, polyolefin polymer such as ethylene-propylene copolymer, vinyl chloride polymer, amide polymer such as nylon or aromatic polyamide, imide polymer, sulfone polymer, polyether sulfone polymer , Polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, and blends of the above polymers. Examples of the polymer forming the transparent protective layer are given below. Of these, cellulose triacetate is preferred.

As the liquid crystalline material to be the optically anisotropic layer 3b, a main chain type in which a conjugated linear atomic group (mesogen) for imparting liquid crystal orientation is introduced into a main chain or a side chain of a polymer. Various types of side chains may be mentioned. For example, a discotic liquid crystal polymer, a nematic liquid crystal polymer, and the like can be given. The formation of the optically anisotropic layer using these liquid crystalline polymers is performed, for example, by rubbing the surface of a thin film of polyimide or polyvinyl alcohol, or obliquely depositing silicon oxide on an alignment-treated surface. The heat treatment is performed by developing the above solution.
The thickness of the optically anisotropic layer is preferably about 0.1 to 10 μm. As the optical compensation film 3, a liquid crystal alignment film in which a liquid crystal polymer is aligned on a support film made of a cellulose triacetate film is preferable.

In the present invention, the protective layer 2 is laminated on one surface of the polarizer 1 or the optical compensation film 3 is laminated on one surface of the polarizer 1 as a protective layer. A protective layer of a transparent film or an optical compensation film 3 may be separately laminated. For forming the protective layer using a transparent film, an appropriate transparent polymer may be used, but those having excellent transparency, mechanical strength, heat stability, moisture barrier properties, etc. are preferably used. As the transparent polymer,
The same as the support film 3a of the optical compensation film 3 can be exemplified. FIGS. 1 and 2 show an example in which a protective layer 6 is provided on the other surface of the polarizer 1.

If the protective layer 2 or the optical compensation film 3 is laminated on at least one side of the polarizer 1, the anti-glare sheet,
Appropriate optical layers such as a diffusion sheet, an antireflection film and a protective plate can be appropriately laminated, and in addition, a protective layer, a retardation film and the like can be combined.

The adhesive constituting the adhesive layer 4 includes:
Various types such as a rubber-based adhesive, an acrylic-based adhesive, and a silicone-based adhesive can be exemplified. Among these, an acrylic-based adhesive is preferable, and the weight-average molecular weight of the base polymer is about 300,000 to 2,500,000. It is preferred that

As the monomers used for the acrylic polymer which is the base polymer of the acrylic pressure-sensitive adhesive, various alkyl (meth) acrylate / (meth) acrylate means acrylate and / or methacrylate. Has the same meaning. You can use｝. Specific examples of such an alkyl (meth) acrylate include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
Examples thereof include 2-ethylhexyl (meth) acrylate, which can be used alone or in combination. Among these, as a monomer unit of the base polymer,
It is preferable to use butyl acrylate in an amount of 30% by weight or more, since the base polymer can be set to exhibit tackiness by adjusting the relaxation modulus of the base polymer.

It is preferable to use a small amount of (meth) acrylic acid instead of part of the alkyl (meth) acrylate in order to impart polarity to the obtained acrylic polymer. Further, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide, or the like may be used in combination as a crosslinkable monomer. Further, if desired, other copolymerizable monomers such as vinyl acetate and styrene can be used together to the extent that the adhesive properties of the acrylic polymer are not impaired.

The acrylic polymer can be produced by various known methods. For example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method, and a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo-based and peroxide-based initiators can be used. Among the above production methods, a solution polymerization method is preferable, and a polar solvent such as ethyl acetate or toluene is generally used as a solvent for the acrylic polymer.

As the base polymer of the rubber-based pressure-sensitive adhesive,
For example, natural rubber, isoprene rubber, styrene-butadiene rubber, recycled rubber, polyisobutylene rubber,
Further, styrene-isoprene-styrene-based rubber, styrene-butadiene-styrene-based rubber and the like can be mentioned. Examples of the base polymer of the silicone-based pressure-sensitive adhesive include dimethylpolysiloxane and diphenylpolysiloxane.

The pressure-sensitive adhesive preferably contains a crosslinking agent. Examples of the crosslinking agent include a polyisocyanate compound, a polyamine compound, a melamine resin, a urea resin, and an epoxy resin. Further, the pressure-sensitive adhesive, if necessary, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, etc., as appropriate within a range not departing from the object of the present invention. Can also be used.

The formation of the adhesive layer 4 is performed on one side of the protective layer 2 or the optical compensation film 3 on one side of a polarizing film to be adhered to a glass substrate of a liquid crystal panel (wide viewing angle). The forming method is not particularly limited, and a method of applying and drying an adhesive (solution) on the protective layer 2 or the optical compensation film 3 of a (wide viewing angle) polarizing film, a release sheet 5 provided with an adhesive layer 4 (Transfer to a wide viewing angle) polarizing film. The thickness of the adhesive layer 4 (dry film thickness) is not particularly limited, but is preferably about 10 to 40 μm.

The constituent material of the release sheet 5 is as follows.
Examples thereof include paper, synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate. The surface of the release sheet 5 may be subjected to silicone treatment, long-chain alkyl treatment, if necessary, in order to enhance the releasability from the adhesive layer 4.
A peeling treatment such as a fluorine treatment may be performed.

The formation of the liquid crystal display device can be performed according to a conventional method. (Wide viewing angle) The polarizing adhesive film can be installed on one side or both sides of the liquid crystal panel. Further, in the liquid crystal display device, an illumination system using a backlight or a reflection plate or the like can be appropriately formed.

[0046]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention thereto.

(Measurement of Contact Angle) (Wide Viewing Angle) The contact angle of cellulose triacetate or the optical compensation film forming the protective layer of the polarizing film with water was measured using a contact angle meter CA-X manufactured by Kyowa Interface Science Co., Ltd. Measured by mold.

(Measurement of Adhesive Strength) (Wide Viewing Angle) The adhesive strength of the adhesive layer of the polarizing adhesive film to glass (1) and the adhesive strength of the protective layer (cellulose triacetate or optical compensation film) to (2) are as follows. Is a value obtained by measuring the normal adhesive force by the method described in (1).

Tensile tester: A tensile tester specified in JIS B 7721 (measured value within a range of 15 to 85% of the capacity of the tester) was used.

Crimping device: When the test piece ((wide viewing angle) polarizing adhesive film) was crimped by an automatic or manual type, only the weight of the roller was applied to the test piece. The roller is a rubber layer with a thickness of about 6 mm, a spring hardness (H _s ) of 80 ± 5, a coating width of about 45 mm, and a diameter (including the rubber layer) of about 95 m.
m and mass of 2000 ± 50 g.

Test pieces: (Wide viewing angle) Three polarizing adhesive films having a width of 25 mm and a length of about 250 mm were prepared.

(Measurement of Adhesive Strength of Glass (1)) Test plate: A glass substrate (same as in each test method) was used.

Method: Wash the surface of the test piece with a suitable solvent such as toluene and dry it sufficiently, then wipe it with a clean dry cloth. Then, place the test piece with the adhesive surface on the lower side and place it in the center of the test piece. The test plate and one end of the test piece were aligned so that they came together. The remaining portion of about 80 mm was allowed to play, and talc was ground or paper was applied to the adhesive surface of the play portion. Next, the test piece was pressed and reciprocated once with a roller at a speed of 5 mm per second. After 20 minutes or more had passed the test piece after the pressure bonding, the test plate was peeled off by 90 degrees and attached to a jig. The test piece was sandwiched by the upper chuck and the jig was sandwiched by the lower chuck. The film was continuously peeled off at a speed of 300 mm ± 20 mm per minute, and the load was read four times every time the film was peeled off by about 20 mm. This test was performed on three test pieces, and the average value of twelve pieces measured from the three test pieces was defined as the 90-degree adhesive strength when peeled off from the glass substrate.

(Measurement of Adhesive Force (2) to Protective Layer) Test plate: SUS-304 steel plate specified in JIS G 4305 (cold-rolled stainless steel plate) having a thickness of about 2.0 m
m, a width of 30 mm, and a length of 180 mm, and the surface thereof was used in the longitudinal direction with a water-resistant abrasive paper of No. 280 specified in JIS R 6253 (water-resistant abrasive paper), which was well polished.

Method: One piece of a test piece was taken and pressed sufficiently on a test plate. The test piece and one end of the test piece are placed on the back surface such that the adhesive side of the test piece is on the lower side and one end of the test piece is aligned with the center of the test plate. Leave the remaining 125mm part to play,
The talc was ground or papered on the adhesive side of the play area. Next, the test piece was pressed and reciprocated once with a roller at a speed of 5 mm per second. The test piece after crimping is 20
After a lapse of more than one minute, the play was folded back at 180 degrees and peeled off by about 25 mm, and then the test piece was sandwiched by the upper chuck and the test plate was sandwiched by the lower chuck. 300mm per minute ±
The film was continuously peeled off at a speed of 30 mm, and the load was read four times every time the film was peeled off by about 20 mm. This test, 3
1 measured on three test pieces
The average of the two values was taken as the adhesive strength when peeled from the back.

(Test Method 1: Adhesive Remaining on Glass) (Wide Viewing Angle) A polarizing adhesive film was attached to a test glass (alkali-free glass) degreased with ethyl alcohol, and then put into an autoclave (50). ℃ 5at
m × 15 min). Further, at 25 ° C. and 50% R.F.
H. For 24 hours. Then, make a cutter at the corner of the polarizing film (wide viewing angle) attached to the test glass, and then slowly (wide viewing angle) the polarizing film, taking care not to break the test glass. The test piece was peeled off, and the adhesion of the pressure-sensitive adhesive on the test glass surface was visually observed.

Production Example (Preparation of Main Polymer) 100 parts by weight of butyl acrylate, 8 parts by weight of acrylic acid, and 1 part by weight of benzoyl peroxide were placed in a separable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube. And ethyl acetate so that the above-mentioned monomer component was 80% by weight. Nitrogen gas was introduced, and nitrogen replacement was performed for about 1 hour while stirring. Next, the flask was heated to 60 ° C. to start the reaction.
After reacting for 6 hours, an acrylic polymer (weight average molecular weight: 1.6 million) solution was obtained.

(Preparation of pressure-sensitive adhesive) The above main polymer 100
A pressure-sensitive adhesive was prepared by adding 0.8 parts by weight of a crosslinking agent (polyfunctional isocyanate compound, manufactured by Nippon Polyurethane Co.) to the parts by weight (solid content).

(Preparation of Pressure-Sensitive Adhesive Sheet) The pressure-sensitive adhesive obtained in the above Production Example was applied to a release-treated polyethylene terephthalate film having a thickness of 38 μm and dried at 150 ° C. for 3 minutes to obtain a pressure-sensitive adhesive having a thickness of 25 μm. I got a sheet.

Comparative Example 1 The pressure-sensitive adhesive sheet obtained in the above Production Example was bonded to a protective layer of a polarizing film (UZTAC, manufactured by Fuji Photo Film Co., Ltd.) having a protective layer of cellulose triacetate to prepare a polarizing pressure-sensitive adhesive film. . Table 1 shows the contact angle of cellulose triacetate used as the protective layer of the polarizing film with water. Also,
In addition, the adhesive strength of the obtained polarizing adhesive film (1), (2)
Was measured, and the above Test Method 1 was carried out, and adhesive residue on the glass surface was observed. Table 1 shows the results.

Comparative Examples 2-3 and Example 1 The surface of the protective layer of cellulose triacetate of the polarizing film used in Comparative Example 1 was heated at a temperature shown in Table 1 with a 15% by weight aqueous sodium hydroxide solution for 0.5 minute. After the saponification treatment, the pressure-sensitive adhesive sheets obtained in the above Production Examples were bonded together to prepare a polarizing pressure-sensitive adhesive film. Table 1 shows the contact angle of the surface of the saponified cellulose triacetate. The adhesive strengths (1) and (2) of the obtained polarizing pressure-sensitive adhesive film were measured, and the adhesive residue on the glass surface was observed in the same manner as in Test Method 1 described above. Table 1 shows the results.

Comparative Examples 4 to 5 and Example 2 The surface of the protective layer of cellulose triacetate of the polarizing film used in Comparative Example 1 was saponified with a 13% by weight aqueous sodium hydroxide solution at a temperature shown in Table 2 for 1 minute. After processing
The pressure-sensitive adhesive sheets obtained in the above Production Examples were bonded together to produce a polarizing pressure-sensitive adhesive film. Table 2 shows the contact angle of the saponified cellulose triacetate surface. The adhesive strengths (1) and (2) of the obtained polarizing pressure-sensitive adhesive film were measured, and the adhesive residue on the glass surface was observed in the same manner as in Test Method 1 described above.
Table 2 shows the results.

Comparative Example 6 Optical compensation film (WVA03 manufactured by Fuji Photo Film Co., Ltd.)
The pressure-sensitive adhesive sheet obtained in the above Production Example was bonded to the surface of the optical compensation film of the wide-viewing angle polarizing film having B) as a protective layer to prepare a wide-viewing angle polarizing pressure-sensitive adhesive film. Table 3 shows the contact angle of the wide viewing angle polarizing film with water on the surface of the optical compensation film. Further, the adhesive strength (1) and (2) of the obtained polarizing adhesive film having a wide viewing angle was measured, and the above-mentioned test method 1 was carried out to observe the adhesive residue on the glass surface.
Table 3 shows the results.

Comparative Example 7 and Examples 3 and 4 The surface of the optical compensation film of the wide viewing angle polarizing film used in Comparative Example 6 was treated with a 15% by weight aqueous sodium hydroxide solution at a temperature shown in Table 3 for 1 minute. After the saponification treatment, the pressure-sensitive adhesive sheets obtained in the above Production Examples were bonded together to prepare a wide-viewing-angle polarizing pressure-sensitive adhesive film. Table 3 shows the contact angle of the saponified optical compensation film surface. The adhesive strength (1) and (2) of the obtained polarizing adhesive film having a wide viewing angle was measured, and adhesive residue on the glass surface was observed in the same manner as in Test Method 1 described above. Table 3 shows the results.

Comparative Examples 8 to 9 and Example 5 The surface of the optical compensation film of the wide viewing angle polarizing film used in Comparative Example 6 was treated with a 13% by weight aqueous solution of sodium hydroxide at a temperature shown in Table 4 for 1 minute. After the saponification treatment, the pressure-sensitive adhesive sheets obtained in the above Production Examples were bonded together to prepare a wide-viewing-angle polarizing pressure-sensitive adhesive film. Table 4 shows the contact angle of the saponified optical compensation film surface. The adhesive strength (1) and (2) of the obtained polarizing adhesive film having a wide viewing angle was measured, and adhesive residue on the glass surface was observed in the same manner as in Test Method 1 described above. Table 4 shows the results.

[0066]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the polarizing adhesive film of the present invention.

FIG. 2 is a sectional view of the wide-viewing-angle polarizing adhesive film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polarizer 2 Cellulose triacetate protective layer 3 Optical compensation film 4 Adhesive layer 5 Release sheet 6 Protective layer

Continued on the front page (72) Inventor Shigeo Kobayashi 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Nei Takahashi 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto Denko stock In-house F term (reference) 2H049 BA02 BA12 BA25 BA27 BB03 BB26 BB27 BB33 BB43 BB51 BB54 BB63 BB65 BC14 BC22 2H091 FA08X FA08Z FA11X FA11Z FC25 GA16 GA17 LA09

Claims (10)

[Claims] 1. A polarizing film having a protective layer made of cellulose triacetate as a base material on at least one surface of a polarizer, wherein the surface of the cellulose triacetate serves as a glass substrate bonding surface of a liquid crystal panel. A polarizing film, wherein a contact angle of cellulose surface with water is 50 ° or less. 2. The polarizing film according to claim 1, wherein the cellulose triacetate is saponified. 3. The polarizing film according to claim 2, wherein the adhesion angle of the cellulose triacetate is lower by 10 ° or more than before the saponification treatment. 4. A wide viewing angle polarizing film having an optical compensation film as a protective layer on at least one surface of a polarizer and the optical compensation film serving as a glass substrate attachment surface of a liquid crystal panel. A wide viewing angle polarizing film having a contact angle with water of 75 ° or less. 5. The wide viewing angle polarizing film according to claim 4, wherein the optical compensation film has been saponified. 6. The wide viewing angle polarizing film according to claim 5, wherein the adhesive angle of the optical compensation film is lower than that before the saponification treatment by 3 ° or more. 7. The wide viewing angle according to claim 4, wherein the optical compensation film is an optical compensation film having a support film and an optically anisotropic layer made of a material exhibiting liquid crystallinity. Polarizing film. 8. A polarized pressure-sensitive adhesive film, wherein an adhesive layer is provided on the protective layer surface of the polarizing film according to claim 1. Description: 9. A wide-viewing-angle polarizing adhesive film, wherein an adhesive layer is provided on the surface of the optical compensation film of the wide-viewing-angle polarizing film according to any one of claims 4 to 7. 10. A liquid crystal display device, wherein the polarizing adhesive film according to claim 8 or the polarizing adhesive film having a wide viewing angle according to claim 9 is attached to at least one side of a liquid crystal panel.