KR20120022608A - Polypropylene resin film, and polarizer, liquid crystal panel and liquid crystal display device using the same - Google Patents

Abstract

PURPOSE: A polypropylene-based resin film is provided to have excellent adhesion, thereby manufacturing a polarizer being hardly exfoliated from a polarizer. CONSTITUTION: A polypropylene-based resin film comprises surface orientation parameter within 0.66-1.50 obtained by Raman spectroscopy by attenuated total reflection method. A polarizer(20) comprises a polarizing film(21) consisting of one-axis elongated polyvinylalcohol based resin film in which iodine or dichroic dye is absorbed, and the polypropylene based resin film(25) laminated on the polarizing film by inserting an adhesive layer. The polypropylene based resin film is laminated to contact the adhesive layer.

Description

Polypropylene resin film, and polarizing plate, liquid crystal panel and liquid crystal display device using the same {Polypropylene resin film, and polarizer, liquid crystal panel and liquid crystal display device using the same}

The present invention relates to a polypropylene resin film, and a polarizing plate, a liquid crystal panel, and a liquid crystal display device using the same, and in particular, a polypropylene resin film bonded to another film via an adhesive, and a polarizing plate, liquid crystal panel, and liquid crystal using the same. It relates to a display device.

Liquid crystal displays have low power consumption, operate at a low voltage, are light and thin, and are used in various display devices. In particular, the market expansion of liquid crystal television is remarkable, and the demand for cost reduction is also remarkable.

Usually, a polarizing plate has the structure which the transparent protective film laminated | stacked on both surfaces or one side of the polarizing film which consists of polyvinyl alcohol-type resin in which the dichroic dye adsorption-oriented. The cellulose acetate-type resin film represented by triacetyl cellulose is used a lot as a protective film. In addition, the adhesive agent which consists of aqueous solution of polyvinyl alcohol-type resin is used for lamination | stacking of a protective film in many cases.

When the polarizing plate which laminated | stacked the protective film which consists of triacetyl cellulose through the adhesive agent on both surfaces or one side of a polarizing film is used for a long time under wet heat conditions, polarization performance will fall, or a protective film and a polarizing film will be easy to peel off, there was.

Then, there exists an attempt to comprise at least one protective film from resin other than a cellulose acetate system. For example, in the polarizing plate in which the protective film was laminated | stacked on both surfaces of a polarizing film, the technique which comprises at least one of a protective film by polypropylene resin is known (for example, refer Unexamined-Japanese-Patent No. 2007-334295). . Since the protective film which consists of polypropylene resins is small in dimensional change and water vapor transmission rate, and is high in tolerance with respect to the organic solvent, it is excellent in moisture heat resistance and dimensional stability. For this reason, there exists an advantage that the adhesiveness between a polarizing film and a protective film falls easily by using the protective film which consists of polypropylene resins.

By the way, as one of the index | index which shows the characteristic of a resin film, there exists a surface orientation degree (it is also called "surface orientation parameter"). For example, a technique using a biaxially stretched polyester film having a surface orientation parameter of 1 to 3 is known in an aqueous paper or the like used in a thermal transfer printing apparatus or the like (see Japanese Patent Laid-Open No. 2005-350615). . According to this technique, when the surface orientation parameter is in the above range, defects such as patterns of the dye-receiving layer, pinholes, etc. are unlikely to occur when the aqueous phase layer is formed, and it is possible to avoid a decrease in production yield.

As mentioned above, it was known that adhesiveness of a protective film and a polarizing film becomes favorable by using polypropylene resin as a protective film. However, studies to further improve the adhesion between the protective film and the polarizing film made of a polypropylene resin have not been made until now. In particular, the relationship between the surface orientation parameters and the adhesiveness of the polypropylene resin film has not been known at all.

An object of the present invention is to provide a polypropylene resin film having good adhesiveness.

In addition, another object of the present invention is to provide a polarizing plate having good adhesion between a polypropylene resin film and a polarizing film and difficult to peel, and a liquid crystal panel and a liquid crystal display device using the same.

As a result of intensive studies to solve the above problems, the inventors have found that the adhesion of the polypropylene resin film can be improved by keeping the surface orientation parameters of the polypropylene resin film within a certain range. It was completed.

That is, according to this invention, the said subject is solved by the polypropylene resin film which has the surface whose surface orientation parameter obtained by the Raman spectroscopy measurement by attenuation total reflection method exists in the range of 0.66-1.50.

It is preferable that the said surface orientation parameter exists in the range of 0.95-1.05.

Moreover, according to this invention, the said subject is a poly as described above laminated | stacked on the said polarizing film via the polarizing film which consists of a uniaxially-stretched polyvinyl alcohol-type resin film in which iodine or a dichroic dye was adsorption-oriented, and an adhesive bond layer. As a polarizing plate provided with a propylene resin film, the said polypropylene resin film is solved by the polarizing plate laminated | stacked so that the said surface may contact the said adhesive bond layer.

It is preferable that the polarizing plate further includes a protective film or an optical compensation film laminated on the side opposite to the surface on which the polypropylene resin film is laminated in the polarizing film.

Moreover, according to this invention, the said subject is solved by the liquid crystal panel provided with a liquid crystal cell and the polarizing plate as described above laminated | stacked on the said liquid crystal cell.

Moreover, according to this invention, the said subject is solved by the liquid crystal display device provided with a surface light source element and the liquid crystal panel as described above.

According to the polypropylene resin film of this invention, since the surface orientation parameter exists in the range of 0.66-1.50, when it laminates on another resin film via an adhesive agent, the adhesiveness of the said other resin film becomes favorable. Moreover, according to the polarizing plate of this invention, it becomes possible to provide the polarizing plate which is hard to peel from a polarizing film by providing the polypropylene resin film with such adhesiveness. Moreover, according to the liquid crystal panel and liquid crystal display device of this invention, by providing such a polarizing plate which is hard to peel off, it becomes possible to provide a durable liquid crystal panel and a liquid crystal display device.

1 is a perspective view schematically showing ATR-Raman spectroscopy.
2 is a schematic cross-sectional view of a polarizing plate in one embodiment of the present invention.
It is a cross-sectional schematic diagram of the liquid crystal panel and liquid crystal display device which used the polarizing plate.
4 is a schematic view showing an example of a film production apparatus that can be suitably used for producing the polypropylene resin film of the present invention.
5 is a schematic view showing another example of a film production apparatus that can be suitably used for producing the polypropylene resin film of the present invention.
6 is a schematic view showing still another example of the film production apparatus that can be suitably used for producing the polypropylene resin film of the present invention.
7 is an ATR-Raman spectrum diagram of the polypropylene resin film of Example 1. FIG.
8 is an ATR-Raman spectrum diagram of a polypropylene resin film of Comparative Example 1. FIG.
It is a cross-sectional schematic diagram which shows the laminated constitution of the sample for peeling tests.
10 is a plan view illustrating a test method of a peel test.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described with reference to drawings. In addition, this invention is not limited by the member, arrangement | positioning, etc. which are demonstrated below, These members etc. can be suitably modified according to the meaning of this invention. Hereinafter, a polarizing plate, a liquid crystal panel having the same, and a liquid crystal display device will be described.

<Polarizing plate>

It is a figure which shows the polarizing plate in one Embodiment of this invention, and shows the cross-sectional schematic diagram of a polarizing plate. As shown in this figure, the polarizing plate 20 is equipped with the polarizing film 21 and the polypropylene resin film 25 at least laminated | stacked on one side of this polarizing film 21 at least. The polarizing film 21 and the polypropylene resin film 25 are bonded together and laminated | stacked through the adhesive bond layer 29. FIG.

In this embodiment, the transparent resin film 23 is laminated | stacked on the surface on the opposite side to the side where the polypropylene resin film 25 is laminated among the surfaces of the polarizing film 21. However, in the present invention, the transparent resin film 23 is not an essential component.

<Liquid crystal panel and liquid crystal display device>

3 is a schematic cross-sectional view showing an example of the basic layer structure of the liquid crystal panel 2 and the liquid crystal display device 1 to which the present invention is applied. As shown in this figure, the polarizing plate 20 is bonded to the liquid crystal cell 40 and is used as a component of the liquid crystal panel 2. The liquid crystal panel 2 becomes a structural member of the liquid crystal display device 1. The liquid crystal panel 2 is formed by the liquid crystal cell 40, the polarizing plate 20 bonded to the back side of the liquid crystal cell 40, and the polarizing plate 30 bonded to the viewing side of the liquid crystal cell 40. Consists of. The liquid crystal display device 1 is composed of a liquid crystal panel 2, a backlight 10, and a light diffusion plate 50. In the liquid crystal display device 1, the liquid crystal panel 2 is disposed such that the polarizing plate 20 is on the backlight 10 side, that is, the polypropylene resin film 25 faces the light diffusion plate 50. . The polarizing plate 20 and the polarizing plate 30 are bonded to the liquid crystal cell 40 via the adhesive layer 27, respectively. Here, the back side means the backlight 10 side when the liquid crystal panel 2 is mounted on the liquid crystal display device 1. In addition, the visual recognition side means the side opposite to the backlight 10 when the liquid crystal panel 2 is mounted in the liquid crystal display device 1.

The light diffusion plate 50 is a member having a function of diffusing light from the backlight 10. As the light diffusion plate 50, for example, particles which are light diffusing agents are dispersed in a thermoplastic resin to impart light diffusivity, irregularities are formed on the surface of the thermoplastic resin film to impart light diffusivity, and the thermoplastic resin film The coating layer of the resin composition in which particle | grains were disperse | distributed to the surface, and the thing which provided light diffusivity may be sufficient. The thickness of the light diffusion plate 50 may be about 0.1 to 5 mm.

Between the light diffusion plate 50 and the liquid crystal panel 2, a sheet or film showing other optical functionality such as a brightness enhancement sheet (such as a reflective polarizing film `` DBEF series '' sold by 3M), a light diffusion sheet, You can also place it. The sheet or film which shows another optical functionality can also be arrange | positioned 2 or more types and multiple types as needed. Below, each film which comprises the polarizing plate 20 of a back side is demonstrated.

[A] polarizing film

The polarizing film 21 is a member having a function of converting natural light into linearly polarized light. As the polarizing film 21, what adsorbed and oriented a dichroic dye to the polyvinyl alcohol-type resin film uniaxially stretched can be used. As polyvinyl alcohol-type resin, the thing which saponified polyvinyl acetate type resin can be used, As polyvinyl acetate type resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, the air of vinyl acetate and the other monomer copolymerizable to this Coalescing and the like are exemplified. 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 saponification degree of polyvinyl alcohol-type resin is about 85-100 mol% normally, Preferably it is 98 mol% or more. The polyvinyl alcohol-based resin may be modified. For example, polyvinyl formal, polyvinyl acetal, or the like modified with aldehydes can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

What formed such a polyvinyl alcohol-type resin into a film is used as a raw film of the polarizing film 21. FIG. The method of forming a polyvinyl alcohol-type resin into a film is not specifically limited, It can form into a film by a well-known method. Although the thickness of a polyvinyl alcohol-type raw film is not specifically limited, For example, it is about 10-150 micrometers.

The polarizing film 21 is usually a step of uniaxially stretching such a polyvinyl alcohol-based resin film, a step of adsorbing the dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye, and a dichroic dye adsorbed. It manufactures through the process of processing the polyvinyl alcohol-type resin film which was made into the aqueous solution of boric acid, and the process of washing with water after the process by aqueous solution of boric acid.

Uniaxial stretching of a polyvinyl alcohol-type resin film can be performed simultaneously with or after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing, such uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, uniaxial stretching can also be performed in several steps shown here. As uniaxial stretching, the method of extending | stretching uniaxially between the rolls from which a circumferential speed differs, the method of extending | stretching uniaxially using a heat roll, etc. can be employ | adopted. In addition, uniaxial stretching may be dry extending | stretching extending | stretching in air | atmosphere, and wet extending | stretching extending | stretching in the state which swelled the polyvinyl alcohol-type resin film using solvents, such as water, may be sufficient as it. The draw ratio is usually about 3 to 8 times.

The extending direction of the polyvinyl alcohol-type resin film is made into the direction parallel to the longitudinal direction of the elongate polarizing film 21. For this reason, the absorption axis of the polarizing film 21 becomes the extending | stretching direction of a polyvinyl alcohol-type resin film, ie, the direction parallel to the longitudinal direction of the elongate polarizing film 21.

Dyeing by the dichroic dye of a polyvinyl alcohol-type resin film can be performed by the method of immersing a polyvinyl alcohol-type resin film in the aqueous solution containing a dichroic dye, for example. As a dichroic dye, an iodine and a dichroic dye are used specifically ,. In addition, the polyvinyl alcohol-based resin film is preferably subjected to a treatment of swelling by immersion in water before dyeing treatment.

When using iodine as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing iodine and potassium iodide is employ | adopted normally. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by weight per 100 parts by weight of water, and the content of potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is about 20-40 degreeC normally. In addition, the immersion time (dyeing time) in this aqueous solution is about 20 to 1,800 second normally.

On the other hand, when using a dichroic dye as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing water-soluble dichroic dye is employ | adopted normally. Content of the dichroic dye in this aqueous solution is about 1 * 10 <^-4> -10 weight part normally per 100 weight part of water, Preferably it is about 1 * 10 <^-3> -1 weight part. This aqueous solution may contain inorganic salts, such as sodium sulfate, as a dyeing adjuvant. The temperature of the dichroic dye aqueous solution used for dyeing is about 20-80 degreeC normally. In addition, the immersion time (dyeing time) in this aqueous solution is about 10 to 1,800 second normally.

The boric acid treatment after dyeing with a dichroic dye can be performed by immersing the dyed polyvinyl alcohol-type resin film in boric acid containing aqueous solution. Content of boric acid in boric-acid containing aqueous solution is about 2-15 weight part normally per 100 weight part of water, Preferably it is about 5-12 weight part. When using iodine as a dichroic dye, it is preferable that this boric acid containing aqueous solution contains potassium iodide. Content of potassium iodide in boric-acid containing aqueous solution is about 0.1-15 weight part normally per 100 weight part of water, Preferably it is about 5-12 weight part. Immersion time in boric acid containing aqueous solution is about 60 to 1,200 second normally, Preferably it is about 150 to 600 second, More preferably, it is about 200 to 400 second. The temperature of the boric acid containing aqueous solution is 50 degreeC or more normally, Preferably it is 50-85 degreeC, More preferably, it is 60-80 degreeC.

The polyvinyl alcohol-based resin film after boric acid treatment is usually washed with water. A water washing process can be performed by immersing the polyvinyl alcohol-type resin film processed by boric acid in water, for example. The temperature of the water in a water washing process is about 5-40 degreeC normally, and immersion time is about 1 to 120 second normally.

After washing with water, a drying treatment is applied to obtain the polarizing film 21. Drying process can be performed using a hot air dryer or a far-infrared heater. The temperature of a drying process is about 30-100 degreeC normally, Preferably it is 50-80 degreeC. The drying treatment time is usually about 60 to 600 seconds, preferably 120 to 600 seconds.

In this way, the polyvinyl alcohol-based resin film is subjected to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment to obtain a polarizing film 21. The thickness of the polarizing film 21 can be about 2-40 micrometers, for example.

[B] Polypropylene resin film

The polypropylene resin film 25 is mainly composed of polypropylene resin and has a function of protecting the polarizing film 21.

The polypropylene resin film 25 of the present invention has a surface (bonding surface) on which the polarizing film 21 is laminated at least through the adhesive layer 29 among the film surfaces (two main surfaces of the film). ), The surface orientation parameter obtained by Raman spectroscopy measurement by the Attenuated Total Reflection method (hereinafter referred to as the "ATR method") is characterized in that it is within the range of 0.66 to 1.50. The polypropylene resin film 25 having such a bonding surface is excellent in adhesiveness when laminated on the polarizing film 21 via the adhesive layer 29 so that the bonding surface faces the adhesive layer 29. Do. Therefore, by using the polypropylene resin film 25 as a protective film of the polarizing plate 20, the polarizing plate excellent in adhesive strength with the polarizing film 21 and high in durability can be obtained. The surface orientation parameters of the surface of the polypropylene resin film 25 are more preferably in the range of 0.95 to 1.05, and ideally 1.00. As the surface orientation parameter is closer to 1.00, the molecular orientation of the surface of the polypropylene resin film 25 becomes random (no orientation), and the adhesion with the polarizing film 21 becomes better. Hereinafter, the Raman spectroscopy measurement method by ATR method is called "ATR-Raman spectroscopy".

Surface orientation parameters can be measured using a Raman spectrophotometer. The measurement of the surface orientation parameter first measures the Raman spectrum of the surface of the polypropylene resin film 25 by ATR method. The ATR method here is a method of spectroscopically measuring the bonding surface of the polypropylene resin film 25 as a measurement surface, directly adhering it to a prism having a large refractive index such as high refractive index glass. Specifically, the incident angle of the measurement light is set larger than the boundary angle so that the measurement light totally reflects between the bonding surface of the polypropylene resin film 25 and the prism. And the measurement light is irradiated to the bonding surface, and the total reflection light reflected from the surface of the bonding surface is measured. At this time, the total reflection light penetrates slightly from the surface of the polypropylene resin film 25 to become reflected light. For this reason, according to ATR-Raman spectroscopy, the absorption spectrum regarding the layer from the surface of the polypropylene resin film 25 to a depth of about 100 nm can be obtained.

Here, a surface orientation parameter means the orientation parameter in the area | region where the depth of the surface vicinity of the polypropylene resin film 25 is shallow. The measurement of an orientation parameter is a measurement of the absorption spectrum by said ATR-Raman spectroscopy WHEREIN: It is perpendicular to the plane containing "parallel polarization" parallel to the plane containing incident light and reflected light as measurement light, and the incident light and reflected light. It is made by the method of irradiating "vertical polarization" which is. FIG. 1: is a figure which shows this parallel polarization and vertical polarization typically, and has shown the parallel polarization to P and the vertical polarization to S. FIG. The orientation parameter of the polypropylene resin film 25 is the following formula from the peak intensity of 1153cm ^-1 and 1169cm ^-1 which are the characteristic bands in the crystal of polypropylene in each of parallel polarization and vertical polarization.

(Here, I ₁₁₅₃ is the peak intensity at ₁₁₅₃ cm ^-1 , I ₁₁₆₉ is the peak intensity at ₁₁₆₉ cm ^-1 , "parallel" is the measured value by parallel polarized light, and "vertical" is measured by vertical polarized light. Value). In addition, 1153 cm <^-1> is the basic vibration of a polypropylene, shows the vibration perpendicular | vertical with respect to a molecular chain, 1169 cm <^-1> is the vibration derived from the crystal | crystallization of a polypropylene, and shows the vibration parallel to a molecular chain.

When the surface of the polypropylene resin film 25 is unoriented, the surface orientation parameter is 1.00. In addition, when the polypropylene resin film 25 is oriented in the longitudinal direction (machine direction: MD), the surface orientation parameter shows a value larger than 1.00. On the contrary, when the polypropylene resin film 25 is oriented in the short direction (vertical direction: TD), the surface orientation parameter shows a value smaller than 1.00.

It is not clear why the surface adhesion parameter is closer to the above range, in particular, 1.00, so that the adhesion is excellent as the molecular orientation of the surface is closer to the non-orientation, but the film at the interface between the polypropylene resin film 25 and the adhesive layer There is a possibility that the mechanical strength of the surface is affecting the adhesion. That is, when the surface of the polypropylene resin film 25 is stretched in a constant direction and the molecules are oriented, the tensile strength in the direction increases, while the tensile strength in a direction different from that decreases. For this reason, according to the direction in which the polypropylene resin film 25 is tensioned, it is thought that agglomeration fracture occurs in the surface of a film, and it becomes easy to peel off the film surface. On the other hand, when the surface of the polypropylene resin film 25 is not stretched and the molecules are unoriented, the tensile strength in any direction is also high, and cohesive failure hardly occurs on the surface of the polypropylene resin film 25, and thus adhesion It is thought that the sex will be good.

Moreover, the following several items are mentioned as evaluation parameters obtained from the result by ATR-Raman spectroscopy, and the items which can be evaluated from it.

(1) Evaluation item: orientation Evaluation parameter: peak intensity

(2) Evaluation item: Order… Evaluation parameter: half width of peak

(3) Evaluation item: Constitution… Evaluation parameter: watch position

(4) Evaluation item: degree of crystallinity. Evaluation parameter: peak intensity ratio

Among these, although the orientation of (1) is an item related to adhesiveness as mentioned above, it can also measure about the order of (2) and the composition of (3). On the other hand, the degree of crystallinity of (4) cannot be evaluated because the measurement in the range of 808 to 840 cm ^-1 cannot be performed due to the constraints on the apparatus. This invention is characterized by the point that adhesiveness becomes favorable when it is focusing on the orientation of (1) in said (1)-(4) and a surface orientation parameter exists in a predetermined range.

In this invention, since the protective film laminated | stacked on the polarizing film 21 is a polypropylene resin film, it has the following advantages. Since the polypropylene resin has a small photoelastic coefficient around 2 × 10 ⁻¹³ cm 2 / dyne and low moisture permeability, the polarizing plate 20 provided with the polypropylene resin film 25 is applied to the liquid crystal cell 40. Thereby, it can be set as the liquid crystal display device 1 excellent in the durability in wet heat conditions. In addition, the adhesiveness of the polypropylene resin film 25 to the polarizing film 21 may not be about triacetyl cellulose film, and sufficient polypropylene resin film 25 is sufficient when using various well-known adhesive agents. It can adhere to the polarizing film 21 by intensity.

The polypropylene resin may be composed of a propylene homopolymer, or may be a copolymer of a small amount of a comonomer copolymerizable with propylene as a main component. The polypropylene resin made of a copolymer may be a resin containing a comonomer unit in a range of, for example, 20% by weight or less, preferably 10% by weight or less, more preferably 7% by weight or less. Moreover, content of the comonomer unit in a copolymer becomes like this. Preferably it is 1 weight% or more, More preferably, it is 3 weight% or more. By making content of a comonomer unit into 1 weight% or more, workability and transparency can be improved significantly. On the other hand, when content of a comonomer unit exceeds 20 weight%, melting | fusing point of a polypropylene resin falls and there exists a tendency for heat resistance to fall. In addition, when using as a copolymer of 2 or more types of comonomers and a propylene, it is preferable that the sum total content of the unit derived from all the comonomers contained in this copolymer is the said range.

The comonomer copolymerized with propylene may be, for example, ethylene or an α-olefin having 4 to 20 carbon atoms. As an alpha olefin, the following are mentioned specifically ,.

1-butene, 2-methyl-1-propene (above C ₄ );

1-pentene, 2-methyl-1-butene, 3-methyl-1-butene (above C ₅ );

1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3- Dimethyl-1-butene (above C ₆ );

1-heptene, 2-methyl-1-hexene, 2,3-dimethyl-1-pentene, 2-ethyl-1-pentene, 2-methyl-3-ethyl-1-butene (above C ₇ );

1-octene, 5-methyl-1-heptene, 2-ethyl-1-hexene, 3,3-dimethyl-1-hexene, 2-methyl-3-ethyl-1-pentene, 2,3,4-trimethyl- 1-pentene, 2-propyl-1-pentene, 2,3-diethyl-1-butene (more than C ₈ );

1-nonene (C ₉ ); 1-decene (C ₁₀ ); 1-undecene (C ₁₁ );

1-dodecene (C ₁₂ ); 1-tridecene (C ₁₃ ); 1-tetradecene (C ₁₄ );

1-pentadecene (C ₁₅ ); 1-hexadecene (C ₁₆ ); 1-heptadecene (C ₁₇ );

1-octadecene (C ₁₈ ); 1-nonadecene (C ₁₉ ) and the like.

Among the α-olefins, α-olefins having 4 to 12 carbon atoms are preferable, and specifically, 1-butene and 2-methyl-1-propene; 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene; 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3- Dimethyl-1-butene; 1-heptene, 2-methyl-1-hexene, 2,3-dimethyl-1-pentene, 2-ethyl-1-pentene, 2-methyl-3-ethyl-1-butene; 1-octene, 5-methyl-1-heptene, 2-ethyl-1-hexene, 3,3-dimethyl-1-hexene, 2-methyl-3-ethyl-1-pentene, 2,3,4-trimethyl- 1-pentene, 2-propyl-1-pentene, 2,3-diethyl-1-butene; 1-nonene; 1-decene; 1-undecene; 1-dodecene, etc. are mentioned. From the viewpoint of copolymerization, 1-butene, 1-pentene, 1-hexene and 1-octene are preferable, and 1-butene and 1-hexene are more preferable.

The copolymer may be a random copolymer or a block copolymer. Preferred copolymers include propylene / ethylene copolymers and propylene / 1-butene copolymers. In the propylene / ethylene copolymer and the propylene / 1-butene copolymer, the content of the ethylene unit and the content of the 1-butene unit are made, for example, of the "Polymer Analysis Handbook" (1995, issued by Kinokuni Bookstore). It can be obtained by performing an infrared (IR) spectrum measurement by the method described on page 616.

From the viewpoint of improving the transparency and processability of the polypropylene resin film 25 bonded to the polarizing film 21, the copolymer is preferably a random copolymer of propylene mainly composed of propylene and ethylene or the α-olefin. And it is more preferable that it is a random copolymer of propylene and ethylene. As described above, the content of the ethylene unit in the propylene / ethylene random copolymer is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, still more preferably 3 to 7% by weight. Do.

The stereoregularity of the polypropylene resin may be any of isotactic, syndiotactic, and atactic. In the present invention, a polypropylene resin of syndiotactic or isotactic is preferably used in terms of heat resistance.

The polypropylene resin preferably has a melt flow rate (MFR) measured at a temperature of 230 ° C. and a load of 21.18 N, in the range of 0.1 to 200 g / 10 minutes, in accordance with JIS K 7210, and 0.5 to 50 g / 10 minutes. It is more preferable to exist in the range of. By using the polypropylene resin in which MFR exists in this range, the uniform polypropylene resin film 25 can be obtained without putting a large load on an extruder.

Polypropylene resin can be manufactured by the method of homopolymerizing propylene and the method of copolymerizing propylene and another copolymerizable comonomer using a well-known polymerization catalyst. As a well-known polymerization catalyst, the following are mentioned, for example.

(1) a Ti-Mg catalyst composed of a solid catalyst component containing magnesium, titanium and halogen as essential components,

(2) a catalyst system in which a solid catalyst component containing magnesium, titanium, and halogen as an essential component is combined with an organoaluminum compound and, if necessary, a third component such as an electron donating compound;

(3) metallocene catalysts;

Among these catalyst systems, in the production of polypropylene resins, the catalyst system of the above (2) can be used most generally. Preferred examples of the organoaluminum compound in the catalyst system of the above (2) include triethylaluminum, triisobutylaluminum, a mixture of triethylaluminum and diethylaluminum chloride, tetraethyldialumoxane, and the like. Preferred examples of the compound include cyclohexylethyldimethoxysilane, tert-butylpropyldimethoxysilane, tert-butylethyldimethoxysilane, dicyclopentyldimethoxysilane and the like.

As a solid catalyst component of said (1) and (2), For example, Unexamined-Japanese-Patent No. 61-218606, Unexamined-Japanese-Patent No. 61-287904, Unexamined-Japanese-Patent No. ( The catalyst system described in the flat 7-216017 grade | etc., Is mentioned. Moreover, as a metallocene catalyst of said (3), the catalyst system as described in patent 22587251, patent 2627669, patent 2668732 etc. is mentioned, for example.

The polypropylene resin is, for example, a solution polymerization method using an inert solvent represented by a hydrocarbon compound such as hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, liquid monomer It can manufacture by the bulk polymerization method used as a solvent, the gas phase polymerization method which polymerizes the monomer of a gas as it is. The polymerization by such a method may be carried out batchwise or continuously.

A well-known additive may be mix | blended with polypropylene resin. As an additive, antioxidant, a ultraviolet absorber, an antistatic agent, a lubricating agent, a nucleating agent, an antifog additive, an anti blocking agent, etc. are mentioned, for example. Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, hindered amine light stabilizers, and the like. Further, in one molecule, for example, a phenolic antioxidant mechanism and Complex antioxidants having units having a phosphorus antioxidant mechanism can also be used. As a ultraviolet absorber, ultraviolet absorbers, such as a 2-hydroxy benzophenone system and the hydroxyphenyl benzotriazole system, a benzoate system sunscreen etc. are mentioned, for example. The antistatic agent may be any of polymer type, oligomer type and monomer type. Examples of the lubricant include higher fatty acid amides such as eruccinic acid amide and oleic acid amide, higher fatty acids such as stearic acid and salts thereof. As a nucleating agent, polymeric nucleating agents, such as a sorbitol type nucleating agent, an organic phosphate type nucleating agent, and polyvinyl cycloalkane, etc. are mentioned, for example. As the anti-blocking agent, fine particles having a circular shape or a shape close thereto can be used regardless of the inorganic or organic type. Two or more types of said additive may be used together.

Polypropylene resin can be formed into a film by arbitrary methods, and it can be set as the polypropylene resin film 25. It is preferable that this polypropylene resin film 25 is transparent and substantially does not have in-plane retardation. For example, polypropylene-based resin substantially free from in-plane retardation by an extrusion molding method from molten resin, a solvent casting method of casting a resin dissolved in an organic solvent on a flat plate, and removing the solvent to form a film. Film 25 can be obtained.

The thickness of the polypropylene resin film 25 is 20-200 micrometers normally, Preferably it is 20-120 micrometers. When the thickness of the polypropylene-based resin film 25 is less than 20 µm, the handling property tends to be inferior, and even when the thickness exceeds 200 µm, the handling property may be lowered by increasing the rigidity of the film.

The polypropylene resin film 25 needs to be excellent in transparency. Specifically, the haze value measured according to JIS K 7361 is 10% or less, preferably 7% or less. When the haze value exceeds 10%, when the obtained polarizing plate 20 is applied to the liquid crystal display device 1, the white luminance tends to decrease and the screen tends to be dark. In addition, the haze value measured according to JISK7361 is a following formula:

(Diffusion transmittance / total light transmittance) x 100 (%)

Is defined.

The polypropylene resin film 25 may be formed as a light collecting film by forming a prism or a lens shape on the surface of the surface opposite to the polarizing film 21 by shaping. 2B shows a polarizing plate 60 with a light collecting film 65. The light condensing film 65 has a brightness enhancement function for condensing the light emitted from the backlight 10 to the liquid crystal cell 40, and also serves as a protection function for protecting the polarizing film 21. The light condensing film 65 deflects light emitted obliquely from the backlight 10 at the inclined surface portion of the prism shape or the lens shape and reflects the light toward the liquid crystal cell 40. As a result, the light emitted obliquely from the backlight 10 is focused on the liquid crystal cell 40.

As a method of forming a prism shape or a lens shape on the surface of the polypropylene resin film 25, it is a method of thermally transferring a prism shape or a lens shape to polypropylene resin, and hardened | cured by an ultraviolet-ray etc. on a polypropylene resin film. The prism shape, the method of shaping | molding a lens shape with active energy ray curable resin, etc. are mentioned.

In addition, in the surface of the polypropylene resin film 25 on the opposite side to the polarizing film 21 from the viewpoint of the prevention of frictional scratches in the manufacturing process of the liquid crystal panel 2 or the liquid crystal display device 1 using the same, You may perform a hard-coat process. Moreover, you may add antiglare process from a viewpoint of the moire reduction by interference of a prism sheet and a color filter.

Moreover, you may laminate | stack a protective film or an adhesive layer in the surface on the opposite side to the polarizing film 21 among the surfaces of the polypropylene resin film 25. FIG. Moreover, you may provide optical films, such as a reflective polarizing film like the thing illustrated by the "DBEF series" sold by 3M company via the adhesive layer.

[C] transparent resin film

The transparent resin film 23 is a film bonded to the surface of the polarizing film 21, and the film which has a various property according to the characteristic calculated | required by the liquid crystal panel 2 and the liquid crystal display device 1 can be employ | adopted. As the transparent resin film 23, optical compensation films, such as a protective film for protecting the surface of the polarizing film 21, and a phase difference film for solving the problem of the viewing angle characteristic of the liquid crystal display device 1, are employ | adopted, for example. can do. As the protective film, for example, a haze value of 0.5% or less, and an in-plane retardation value R ₀ of less than 30 nm can be employed. Further, as a phase difference film, the in-plane retardation value R ₀ in the range of 30 to 200nm, it can be a retardation value R _th in the thickness direction is employed a biaxial retardation film is in a range of 30 to 350nm. In-plane retardation value R ₀ herein and the thickness retardation value R _th is a value at a wavelength of 590nm, an so on.

It is preferable that the Garray method stiffness measured in accordance with JISL1096 is 350 mgf or less, It is more preferable that it is 200 mgf or less, and, as for the transparent resin film 23, it is still more preferable that it is 150 mgf or less. Thus, since the rigidity of the polarizing plate 20 obtained is reduced by using the transparent resin film 23 with small ductility, handling property at the time of bonding to the liquid crystal cell 40 can be improved.

The resin material which comprises the transparent resin film 23 is not specifically limited. As an example of a resin material, (meth) acrylic-type resins, such as methyl methacrylate type resin ((meth) acrylic-type resin means methacrylic resin or acrylic resin], an olefin resin, polyvinyl chloride resin, cellulose type Resin, styrene resin, acrylonitrile butadiene styrene copolymer resin, acrylonitrile styrene copolymer resin, polyvinyl acetate resin, polyvinylidene chloride resin, polyamide resin, polyacetal resin, poly Carbonate resin, modified polyphenylene ether resin, polyester resin (for example, polybutylene terephthalate resin, polyethylene terephthalate resin, etc.), polysulfone resin, polyethersulfone resin, polyarylene Resin, polyamideimide resin, polyimide resin, epoxy resin, oxetane resin. These resin can contain an additive in the range which does not impair transparency and adhesiveness with the polarizing film 21.

[C-1] optical compensation film

As the transparent resin film 23, an optical compensation film can be employed as described above. As such an optical compensation film, the retardation film etc. which extended | stretched the unstretched film which consists of said resin material, expressed the phase difference, and set it as the transparent resin film 23 are mentioned. In addition, there is also a method of forming a phase difference film by applying a material having an alignment capability such as liquid crystal to a substrate and orienting the same to express and fix the phase difference (for example, Example 4 of JP-A-2004-272202). Or a method for forming an optically anisotropic layer containing a rod-like liquid crystalline compound on the transparent support according to Example 3 of JP-A-2004-233872. In particular, it is preferable to express birefringence in the biaxial direction by sequential biaxial stretching. The draw ratio at this time is about 1.1 to 10 times in the direction in which the optical axis is expressed (the direction in which the draw ratio is large, which is the slow axis) in the longitudinal direction and the transverse direction, and is perpendicular to it. What is necessary is just to select suitably according to the phase difference value required from the range of about 1.1-7 times (in the direction which becomes a fastening axis as a direction of draw ratio being small). An optical axis may be expressed in the horizontal direction of a film, and an optical axis may be expressed in a longitudinal direction. As a commercial item of the cellulose acetate type resin film provided with such retardation characteristics, "KC4FR-1" (Reference: Konica Minolta Opto Co., Ltd. product), "KC4HR-1" (Reference: Konica Minolta Opto Co., Ltd. make) etc. are mentioned. Can be mentioned.

Next, the retardation value of the transparent resin film 23 is demonstrated. When the refractive index in the in-plane slow axis direction of the film is n _x , the refractive index in the in-plane fast axis direction (direction perpendicular to the ground axis and in-plane orthogonal) is n _y , the refractive index in the thickness direction is n _z , and the thickness is d. R ₀ and the thickness direction retardation value R _th are defined by the following formulas (I) and (II), respectively.

R ₀ = (n _x -n _y ) × d (I)

R _th = [(n _x + n _y ) / 2-n _z ] × d (II)

In addition, regarding the refractive index, the transparent resin film 23 has following formula (III):

n _x > n _y > n _z (III)

It may be to satisfy the relationship of.

As described above, the in-plane retardation value R ₀ is in the range of 30 to 200 nm, the thickness direction retardation value R _th is in the range of 30 to 350 nm, and the transparent resin film 23 as the retardation film may be applied from this range. It selects suitably according to the characteristic calculated | required by the liquid crystal display device 1 which becomes. The in-plane retardation value R ₀ is preferably 100 nm or less, and the thickness direction retardation value R _th is preferably 80 nm or more and 200 nm or less.

The accuracy of the in-plane retardation value R ₀ is within the center value ± 7 nm, preferably within the center value ± 5 nm, and the precision of the thickness direction retardation value R _th is within the center value ± 15 nm, preferably within the center value ± 10 nm. . When the precision of these values exceeds the said range, there exists a tendency for the visual characteristic of the liquid crystal display device 1 to apply to fall.

The slow-axis angle in the film surface in the transparent resin film 23 is substantially 0 degrees or 90 degrees. When the slow axis deviates from this angle, light leakage occurs when the polarizing plate 20 and the polarizing plate 30 are in the cross nicol state, and when applied to the liquid crystal display device 1, visual characteristics such as front contrast are greatly increased. It tends to be lowered. Moreover, it is preferable that the precision of a slow axis is within the center value +/- 0.7 degrees, and it is more preferable that it is within the center value +/- 0.5 degrees. Light leakage means here that when the axial precision with respect to the transparent resin film 23 of the polarizing film 21, or the axial precision with respect to the liquid crystal cell 40 of the polarizing plate 20 is bad, the liquid crystal display device 1 displays a black display. It refers to a phenomenon where light leaks from the front of the display area during black display. As described above, the deviation of the slow axis in the transparent resin film 23 is reduced, and thus the deviation of the angle formed between the slow axis and the absorption axis of the polarizing film 21 is also reduced, thereby furthermore the front and back of the liquid crystal cell 40. Light leakage can be reduced by improving the axial accuracy of the polarizing plates (polarizing plate 20 and polarizing plate 30) bonded to both surfaces, and making the shift | deviation from the angle of 90 degrees of the absorption axis of both polarizing plates small.

In bonding the transparent resin film 23 to the polarizing film 21, the axial relationship between the two may be selected after considering the viewing angle characteristic and the color change characteristic in the target liquid crystal display device 1. . In large liquid crystal television applications in which front contrast is important, the slow axis of the transparent resin film 23 and the absorption axis of the polarizing film 21 are often disposed so as to be substantially parallel or approximately orthogonal. Here, "approximately parallel or substantially orthogonal" includes the case where it shift | deviates from parallel or orthogonal relationship within the range of about +/- 10 degrees other than the case where it is completely parallel or orthogonal. The deviation of the angle is preferably within ± 5 °, more preferably within ± 2 °. It is preferable that the slow axis of the transparent resin film 23 and the absorption axis of the polarizing film 21 are completely parallel or orthogonal.

[C-2] Protective film

As the transparent resin film 23, a protective film can be employ | adopted as mentioned above. As such a protective film, the non-oriented film which does not have a phase difference substantially in surface inside and thickness direction can be employ | adopted. An oriented film means the unstretched resin film (unstretched film) which formed the resin material into a film.

Since the non-oriented film does not have a phase difference, there is no function of widening the viewing angle of the liquid crystal display device 1 like the biaxial retardation film. However, since the stretching treatment does not need to be performed like the biaxial retardation film, the manufacturing cost is high. low. Therefore, compared with the case where the biaxial retardation film is employ | adopted as the transparent resin film 23, the manufacturing cost of the liquid crystal display device 1 can be made lower. Moreover, since an oriented film does not perform an extending | stretching process, film thickness is comparatively thick and handling property is favorable.

As mentioned above, the transparent resin film 23 as a protective film may be an unstretched film obtained by forming the said resin material by arbitrary methods. It is preferable that such an unstretched film is transparent and substantially free of in-plane retardation. As the film forming method, for example, an extrusion molding method in which molten resin is extruded into a film to form a film, and a solvent casting method in which a resin is dissolved in an organic solvent on a flat plate and then the solvent is removed to form a film can be adopted.

Further, it is preferable because in view of the retardation value R _th in the thickness direction, deviation in thickness of the transparent resin film 23 is thin, to reduce the phase difference value. Specifically, it is preferable that the thickness of the transparent resin film 23 is 15-45 micrometers. Considering not only the handling property of the polarizing plate 20 but also the handling property of the transparent resin film 23 itself, it is more preferable that the thickness of the transparent resin film 23 is 35-45 micrometers.

[D] Adhesive layer

Bonding and lamination | stacking of the polypropylene resin film 25 and the transparent resin film 23 to the polarizing film 21 are normally performed through the adhesive bond layer 29. FIG. The adhesive which forms the adhesive bond layer 29 provided in both surfaces of the polarizing film 21 may be the same kind, or different types may be sufficient as it.

As an adhesive agent, the adhesive agent which uses epoxy resin, urethane resin, cyanoacrylate resin, acrylamide resin, etc. as an adhesive component can be used. One of the adhesive agents preferably used in the present invention is a solvent-free adhesive. A solvent-free adhesive does not contain a significant amount of solvent, and cures a curable compound (monomer or oligomer, etc.) that is cured by heating or irradiation with an active energy ray (for example, ultraviolet ray, visible light, electron beam, X-ray, etc.). It includes and forms an adhesive bond layer by hardening of the said curable compound, and typically contains the curable compound and polymerization initiator which react-harden by heating and irradiation of an active energy ray. In particular, as described above, the polypropylene resin film 25 has a low moisture permeability, so that water drainage becomes poor when a water-based adhesive described later is used, and damage to the polarizing film 21 and deterioration of polarization performance are caused by moisture of the adhesive. Etc. may be caused. Therefore, when bonding the resin film with such a low water vapor transmission rate, a solvent-free adhesive agent is preferable.

In view of rapid curing and productivity improvement of the polarizing plate 20, an active energy ray-curable adhesive that is cured by irradiation of active energy rays can be cited as an example of a preferable adhesive for forming the adhesive layer 29. As an example of such an active energy ray curable adhesive agent, the photocurable adhesive agent hardened | cured by optical energy, such as an ultraviolet-ray or visible light, is mentioned, for example. As a photocurable adhesive agent, it is preferable to harden | cure by cationic polymerization from a reactive viewpoint, In particular, the non-solvent type epoxy adhesive which uses an epoxy compound as a curable compound is a polarizing film 21 and a polypropylene resin film 25, Since it is excellent in adhesiveness with the transparent resin film 23, it is more preferable.

Although it does not restrict | limit especially as an epoxy compound which is a curable compound contained in the said solvent-free epoxy adhesive, It is preferable to harden | cure by cationic polymerization, Epoxy which does not contain an aromatic ring in a molecule especially from a viewpoint of weather resistance, a refractive index, etc. It is more preferable to use a compound. As an epoxy compound which does not contain an aromatic ring in such a molecule | numerator, the hydride of an aromatic epoxy compound, an alicyclic epoxy compound, an aliphatic epoxy compound, etc. can be illustrated. In addition, the epoxy compound which is a curable compound usually has two or more epoxy groups in a molecule | numerator.

First, the hydride of an aromatic epoxy compound is demonstrated. The hydride of an aromatic epoxy compound can be obtained by selectively hydrogenating an aromatic epoxy compound to an aromatic ring in the presence of a catalyst and under pressure. As an aromatic epoxy compound, For example, Bisphenol-type epoxy resins, such as the diglycidyl ether of bisphenol A, the diglycidyl ether of bisphenol F, and the diglycidyl ether of bisphenol S; Novolac type epoxy resins such as phenol novolac epoxy resins, cresol novolac epoxy resins, hydroxybenzaldehyde phenol novolac epoxy resins; And polyfunctional epoxy resins such as glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, and epoxidized polyvinylphenol. Among these, it is preferable to use glycidyl ether of hydrogenated bisphenol A as a hydride of an aromatic epoxy compound.

로 나타내는 구조에 있어서의 가교된 산소 원자 -O-을 의미한다. 상기 화학식에서, m은 2 내지 5의 정수이다.Next, an alicyclic epoxy compound is demonstrated. An alicyclic epoxy compound means the epoxy compound which has one or more epoxy groups couple | bonded with the alicyclic ring, and an "epoxy group couple | bonded with an alicyclic ring" is a chemical formula

The crosslinked oxygen atom -O- in the structure shown by this is meant. In the above formula, m is an integer of 2 to 5.

Therefore, the compound which the group of the form remove | excluding one or some hydrogen atom in (CH2) _m in the said chemical formula _{couple |} bonded with another chemical structure can be an alicyclic epoxy compound. An alicyclic epoxy compound normally has a 2 or more epoxy group in total in a molecule | numerator. One or a plurality of hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. Among these alicyclic epoxy compounds, an epoxy compound having an epoxy cyclopentane ring (m = 3 in the above formula) or an epoxycyclohexane ring (m = 4 in the above formula) can provide an adhesive having excellent adhesive strength. It is used more preferably at the point. Although the structure of an alicyclic epoxy compound is illustrated concretely below, it is not limited to these compounds.

3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate, ethylene bis (3,4 -Epoxycyclohexanecarboxylate), bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, diethylene glycol bis (3,4-epoxy Cyclohexylmethyl ether), ethylene glycol bis (3,4-epoxycyclohexylmethylether), 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrisspiro- [5.2.2.5. 2.2] henicosane (this compound is 3,4-epoxycyclohexanespiro-2 ', 6'-dioxanespiro-3 ", 5" -dioxanespiro-3' '', 4 '' '-Is also a compound which may be called epoxycyclohexane), 4- (3,4-epoxycyclohexyl) -2,6-dioxa-8,9-epoxyspyro [5.5] undecane, 4-vinylcyclohexene Dioxide, bis-2,3-in Foxycyclopentyl ether, dicyclopentadiene dioxide, etc.

Moreover, as said aliphatic epoxy compound, the polyglycidyl ether of an aliphatic polyhydric alcohol or its alkylene oxide adduct is mentioned. More specifically, diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerine, triglycidyl ether of trimethylolpropane, di-glycol of glycol Polyetherpolyol obtained by adding one or two or more alkylene oxides (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as glycidyl ether, diglycidyl ether of propylene glycol, ethylene glycol or propylene glycol, glycerin And polyglycidyl ethers.

An epoxy compound may be used individually by 1 type, or may use 2 or more types together.

The epoxy equivalent of the epoxy compound contained in a non-solvent type epoxy adhesive is 30-3,000 g / equivalent normally, Preferably it is the range of 50-1,500 g / equivalent. When epoxy equivalent is less than 30 g / equivalent, the flexibility of the polarizing plate after hardening may fall, or adhesive strength may fall. On the other hand, when epoxy equivalent exceeds 3,000 g / equivalent, compatibility with the other component contained in an epoxy adhesive may fall.

It is preferable that a non-solvent type epoxy adhesive contains a cationic polymerization initiator in order to cationic polymerization of the said epoxy compound. A cationic polymerization initiator generates cationic species or Lewis acid by irradiation of active energy rays, such as visible light, an ultraviolet-ray, X-rays, an electron beam, or a heating, and starts the polymerization reaction of an epoxy group. In the present invention, any type of cationic polymerization initiator may be used, but it is preferable from the viewpoint of workability that potential is imparted. In addition, below, the cationic polymerization initiator which generate | occur | produces a cationic species or Lewis acid by irradiation of active energy rays, such as visible light, an ultraviolet-ray, X-ray, an electron beam, and starts the polymerization reaction of an epoxy group is also called "photocationic polymerization initiator." .

When the photocationic polymerization initiator is used, curing of the adhesive component at room temperature becomes possible, and thus the need to consider deformation due to heat resistance or expansion of the polarizing film 21 is reduced, and the polypropylene resin film 25 or transparent resin is reduced. The film 23 can be bonded onto the polarizing film 21 with good adhesion. Moreover, when a photocationic polymerization initiator is used, since it acts catalytically by light, even if it mixes with an epoxy adhesive, it is excellent in storage stability and workability.

Although it does not specifically limit as a photocationic polymerization initiator, For example, an onium salt like an aromatic diazonium salt, an aromatic iodonium salt, an aromatic sulfonium salt, an iron- allene complex, etc. are mentioned. These photocationic polymerization initiators may be used independently, respectively and may mix and use 2 or more types. Among these, in particular, the aromatic sulfonium salt is preferably used because it has excellent ultraviolet curability in the wavelength region of 300 nm or more and can provide a cured product having good mechanical strength and adhesive strength.

Such a photo cationic polymerization initiator can be easily obtained as a commercial item, for example, "Kayarad PCI-220" and "Kayarad PCI-620" as a brand name, respectively (refer to Nihon Kayaku Co., Ltd. above). Kaisha Co., Ltd., "UVI-6990" (Reference: Union Carbide Co., Ltd.), "ADECA OPTOMER SP-150", "ADEKA OPTOMER SP-170" (Reference: manufactured by ADEKA, Inc.), " CI-5102 "," CIT-1370 "," CIT-1682 "," CIP-1866S "," CIP-2048S "," CIP-2064S "(reference: Nihon Soda Co., Ltd.)," DPI- 101 "," DPI-102 "," DPI-103 "," DPI-105 "," MPI-103 "," MPI-105 "," BBI-101 "," BBI-102 "," BBI-103 " , "BBI-105", "TPS-101", "TPS-102", "TPS-103", "TPS-105", "MDS-103", "MDS-105", "DTS-102", " DTS-103 "(refer to the above: Midori Chemical Co., Ltd. make)," PI-2074 "(Reference: Rhodia Corporation make), etc. are mentioned.

The compounding quantity of a photocationic polymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of epoxy compounds, Preferably it is 1 weight part or more, More preferably, it is 15 weight part or less.

A solvent-free epoxy adhesive can contain a photosensitizer with a photocationic polymerization initiator as needed. By using a photosensitizer, reactivity is improved and the mechanical strength and adhesive strength of hardened | cured material can be improved. As a photosensitizer, a carbonyl compound, an organic sulfur compound, a persulfide, a redox type compound, an azo and a diazo compound, a halogen compound, a photoreducing dye etc. are mentioned, for example. When mix | blending a photosensitizer, the quantity is about 0.1-20 weight part with respect to 100 weight part of epoxy compounds.

Moreover, as a thermal cationic polymerization initiator which generate | occur | produces cationic species or Lewis acid by heating, and starts the polymerization reaction of an epoxy group, For example, a benzyl sulfonium salt, a thiophenium salt, a thiornium salt, a benzyl ammonium salt, a pyridinium salt, Hydrazinium salt, carboxylic acid ester, sulfonic acid ester, amineamide, etc. are mentioned. These thermal cationic polymerization initiators can also be easily obtained as commercially available products. For example, "Adekaoptone CP77", "Adekaoptone CP66" (see above, manufactured by ADEKA Corporation), " CI-2639 "," CI-2624 "[Reference: Nihon Soda Co., Ltd.]," San-Aid SI-60L "," San-Aid SI-80L "," San-Aid SI-100L " And Sanshin Kagaku Kogyo Co., Ltd.]. These thermal cationic polymerization initiators may be used independently, respectively and may mix and use 2 or more types. Moreover, it is also preferable to use a photocationic polymerization initiator and a thermal cationic polymerization initiator together.

The solvent-free epoxy adhesive may further contain a compound for promoting cationic polymerization, such as oxetane and polyols.

In the case of using a solvent-free epoxy adhesive, the polarizing film 21 and the polypropylene resin film 25 or the transparent resin film 23 are bonded to the polarizing film 21 or the polypropylene resin film 25. Can be performed by apply | coating an adhesive agent to the adhesive surface of the () and the application surface of the polarizing film 21 and the transparent resin film 23, and bonding each film together. There is no particular limitation on the method of applying a solvent-free epoxy adhesive to the polarizing film 21, the polypropylene resin film 25, and the transparent resin film 23, for example, a doctor blade, a wire bar, a die coater, Various coating methods, such as a comma coater and a gravure coater, can be used. In addition, since each coating method has an optimum viscosity range, respectively, you may adjust viscosity using a small amount of solvent. The solvent used for this purpose should just melt | dissolve an epoxy adhesive well, without reducing the optical performance of the polarizing film 21, For example, hydrocarbons represented by toluene, esters represented by ethyl acetate, etc. An organic solvent can be used.

After bonding the polypropylene resin film 25 or the transparent resin film 23 to the polarizing film 21 via the adhesive layer which consists of an uncured epoxy adhesive, an active energy ray is irradiated or heated, The adhesive layer is cured to fix the polypropylene resin film 25 or the transparent resin film 23 on the polarizing film 21. When hardening | curing by irradiation of an active energy ray, the active energy ray which has a light emission distribution in wavelength 400nm or less, among these, an ultraviolet-ray is used preferably. As a specific ultraviolet light source, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, etc. are mentioned. Irradiation intensity and irradiation amount of an active energy ray, such as an ultraviolet-ray, can fully activate a cationic polymerization initiator, and will not adversely affect the film, such as the adhesive bond layer and the polarizing film 21 after hardening (for example, a polarizing film ( The polarization degree, transmittance and color of 21), and transparency of the transparent resin film 23 and the polypropylene resin film 25, such as the function of the polarizing plate 20, are appropriately selected.

Specifically, light irradiation intensity to a photocurable adhesive agent is suitably determined by the composition of the said photocurable adhesive agent, Although it does not specifically limit, The irradiation intensity of the wavelength range effective for activation of a polymerization initiator is 0.1-6000mW / cm <2>. desirable. When the irradiation intensity is 0.1 mW / cm 2 or more, the reaction time is not too long, and when 6000 mW / cm 2 or less, the yellowing or the polarizing film of the photocurable epoxy resin due to the heat radiated from the light source and the heat generated during curing of the photocurable adhesive There is little possibility of causing deterioration of (21). Although the light irradiation time to a photocurable adhesive agent is controlled for every photocurable adhesive agent to harden, it is not specifically limited, It is preferable to set so that the accumulated light quantity represented by the product of said irradiation intensity and irradiation time may be set to 10-10000mJ / cm <2>. . When the accumulated light amount to the photocurable adhesive agent is 10 mJ / cm 2 or more, a sufficient amount of active species derived from a polymerization initiator can be generated to advance the curing reaction more reliably, and when it is 10000 mJ / cm 2 or less, the irradiation time does not become too long, so that good productivity Can be maintained.

Moreover, when hardening by heating, it can heat by a generally known method, and fully activates the temperature and time at that time, a cationic polymerization initiator, and also films, such as the adhesive bond layer and the polarizing film 21 after hardening, It is appropriately selected so as not to adversely affect it.

The thickness of the adhesive bond layer which consists of an epoxy adhesive after hardening is 50 micrometers or less normally, Preferably it is 20 micrometers or less, More preferably, it is 10 micrometers or less, and is usually 1 micrometer or more.

As the adhesive, from the viewpoint of thinning the adhesive layer 29, an aqueous adhesive, that is, an adhesive in which the adhesive component is dissolved in water or the adhesive component is dispersed in water may be used. For example, the aqueous composition using polyvinyl alcohol-type resin or urethane resin as a main component is mentioned as a preferable aqueous adhesive agent.

The polyvinyl alcohol-based resin as a main component of the adhesive is, in addition to partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, amino group-modified polyvinyl alcohol Modified polyvinyl alcohol-based water such as alcohol may be used. The aqueous adhesive whose main component of an adhesive agent is polyvinyl alcohol-type resin is often prepared as an aqueous solution of polyvinyl alcohol-type resin. The concentration of the polyvinyl alcohol-based resin in the water-based adhesive agent is usually about 1 to 10 parts by weight, and preferably 1 to 5 parts by weight with respect to 100 parts by weight of water.

In order to improve adhesiveness, it is preferable to add curable components, such as glyoxal and a water-soluble epoxy resin, or a crosslinking agent to the water-based adhesive agent containing polyvinyl alcohol-type resin as a main component. As a water-soluble epoxy resin, it is obtained by making epichlorohydrin react with the polyamide polyamine obtained by reaction of polyalkylene polyamine like diethylene triamine and triethylene tetramine, and dicarboxylic acid like adipic acid, for example. Polyamide polyamine epoxy resin is mentioned. Commercially available products of such polyamide polyamine epoxy resin include `` Sumirez resin 650 '' and `` Sumirez resin 675 '' sold by Sumika Chemtex Co., Ltd., and `` WS-525 '' sold by Nippon PMC Corporation. These can be used suitably. The addition amount of these curable components or a crosslinking agent is 1-100 weight part normally with respect to 100 weight part of polyvinyl alcohol-type resins, Preferably it is 1-50 weight part. When there is little addition amount, the adhesive improvement effect becomes small, and when there is much addition amount, there exists a tendency for the adhesive bond layer 29 to weaken.

When using urethane resin as a main component of an adhesive agent, the mixture of the polyester-type ionomer type urethane resin and the compound which has glycidyloxy group is mentioned as an example of a suitable aqueous adhesive agent. The polyester ionomer-type urethane resin here is a urethane resin which has a polyester frame | skeleton, and a small amount of ionic component (hydrophilic component) is introduce | transduced in it. Such ionomer-type urethane resin is suitable as an aqueous adhesive, since it is emulsified in water and becomes an emulsion directly, without using an emulsifier. Polyester-type ionomer type urethane resin itself is well-known. For example, JP-A-7-97504 discloses a polyester ionomer-type urethane resin as an example of a polymer dispersant for dispersing a phenolic resin in an aqueous medium. Japanese Unexamined Patent Publication No. 2005-070140 and Japanese Unexamined Patent Publication No. 2005-181817 disclose a cyclone to a polarizing film made of a polyvinyl alcohol-based resin using a mixture of a polyester ionomer-type urethane resin and a compound having a glycidyloxy group as an adhesive. The aspect which joins an olefin resin film is disclosed.

As a method of bonding the polypropylene resin film 25 and the transparent resin film 23 to the surface of the polarizing film 21 using an aqueous adhesive, a conventionally known method can be used. For example, of the film bonded to the polarizing film 21 and / or this by the casting method, the Meyer bar coating method, the gravure coating method, the comma 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 an adhesive surface and superimposing both is mentioned. The casting method is a method in which an adhesive is dipped and expanded on the surface of the film to be coated while moving in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between them.

After apply | coating an aqueous adhesive agent by the said method, both are bonded together by sandwiching and bonding together the polarizing film 21 and the film bonded to it with a nip roll etc. Moreover, after dripping an adhesive agent between the polarizing film 21 and the film bonded to it, the method of pressurizing this laminated body with a roll etc. and spreading it uniformly can also be used suitably. In this case, it is possible to use a metal, rubber | gum, etc. as a material of a roll. Moreover, after dripping an adhesive agent between the polarizing film 21 and the film bonded to it, the method of making this laminated body pass between a roll and a roll, and pressing and spreading is also preferably employ | adopted. In this case, these rolls may be the same material or may be different materials.

Moreover, it is preferable that the thickness of the adhesive bond layer 29 which consists of an aqueous adhesive agent after bonding together using a nip roll etc. before drying or hardening is 5 micrometers or less, and it is preferable that it is 0.01 micrometers or more.

The adhesive surface of the polarizing film 21 and / or the film bonded thereto may be appropriately subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, frame (flame) treatment or saponification treatment in order to improve the adhesiveness. good. As a saponification process, the method of immersing in alkaline aqueous solution, such as sodium hydroxide and potassium hydroxide, is mentioned.

The laminated body bonded through the water-based adhesive agent is usually subjected to a drying treatment to dry and cure the adhesive layer 29. A drying process can be performed by spraying hot air, for example. Drying temperature is normally selected in the range of about 40-100 degreeC, Preferably it is 60-100 degreeC. Drying time is about 20 to 1,200 second, for example. The thickness of the adhesive bond layer 29 after drying is about 0.001-5 micrometers normally, Preferably it is 0.01 micrometer or more, More preferably, it is 2 micrometers or less, More preferably, it is 1 micrometer or less. If the thickness of the adhesive bond layer 29 becomes large too much, the polarizing plate 20 will become a bad appearance.

After the drying treatment, curing at least half a day, usually one or more days, at a temperature of room temperature or more may be obtained to obtain sufficient adhesive strength. Such curing is typically carried out in a rolled state. Preferable curing temperature is the range of 30-50 degreeC, More preferably, it is 35 degreeC or more and 45 degrees C or less. When curing temperature exceeds 50 degreeC, what is called "a phenomenon in which winding becomes hard" easily arises in the state wound with a roll. In addition, the humidity at the time of curing is not particularly limited, but is preferably selected so that the relative humidity is in the range of about 0% RH to about 70% RH. Curing time becomes like this. Preferably it is about 1 to 10 days, More preferably, it is about 2 to 7 days.

<Method for producing polypropylene resin film>

4-6 is schematic which shows the example of the film manufacturing apparatus which can be used suitably for manufacture of the polypropylene resin film 25 of this invention. Hereinafter, with reference to FIGS. 4-6, the structure of the film manufacturing apparatus which can be used suitably for manufacture of the polypropylene resin film 25 of this invention, and the manufacturing method of the polypropylene resin film 25 using the same. Explain about.

(Extruder)

In manufacture of the polypropylene resin film 25 using the film manufacturing apparatus 100 shown in FIG. 4 (it is the same also about the film manufacturing apparatuses 200 and 300 shown in FIG. 5 and FIG. 6), the hopper first Said polypropylene resin is thrown into the extruder 11 from (not shown). At this time, in order to suppress deterioration, decomposition, etc. of the polypropylene resin in kneading | mixing, before supplying resin to the extruder 11, it is polypropylene system at 40 degreeC or more and temperature below (Tm-20 degreeC) in nitrogen gas. It is preferable to pre-dry the pellet of resin for about 1 to 10 hours (Tm [degreeC] is melting peak temperature of polypropylene resin in the differential scanning calorimetry prescribed | regulated by JISK7121). In the extruder 11, gas substitution is preferably performed with an inert gas such as nitrogen gas or argon gas at 20 to 120 ° C. In addition, the extruder 11 is an apparatus which extrudes the injected polypropylene resin while melt-kneading and conveys the molten polypropylene resin to the T die 12.

When melt-kneading a polypropylene resin in the extruder 11, a screw is used. As the screw, when the extruder 11 is a single screw extruder, a full flight type of L / D = 24 to 36 and a compression ratio of 1.5 to 4 , A type having a kneading portion of a barrier type or an abrasion type can be used. It is preferable to use the barrier type screw of L / D = 28-36 and compression ratio 2.5-3.5 from a viewpoint of suppressing deterioration and decomposition of a polypropylene resin, and melt-kneading uniformly.

In addition, in order to remove volatile gas generated when the polypropylene resin deteriorates or decomposes, an orifice of 1 mm or more and 5 mmφ or less is formed at the tip of the extruder 11 to increase the resin pressure at the tip of the extruder 11. It is also preferable. Increasing the resin pressure at the tip of the extruder 11 means increasing the back pressure at the tip, whereby the stability of the extrusion can be improved. The orifice to be used is more preferably 2 mmφ or more and 4 mmφ or less. Moreover, it is preferable to mount a gear pump through the adapter between the extruder 11 and the T die 12 from a viewpoint of suppressing the extrusion fluctuation | variation of polypropylene resin. Moreover, in order to remove the foreign material in a polypropylene resin, it is preferable to attach a leaf disc filter (not shown).

(T die)

The T die 12 is connected to the extruder 11, and has a manifold 12b therein for expanding the molten polypropylene resin conveyed from the extruder 11 in the lateral direction. Further, a discharge port 12a is formed in the lower portion of the T die 12 to communicate with the manifold 12b and to discharge the molten polypropylene-based resin that is laterally expanded by the manifold 12b. For this reason, the molten polypropylene resin discharged | emitted from the discharge port 12a of the T die 12 will be shape | molded in the sheet form (Hereinafter, the molten polypropylene resin shape | molded in this sheet form is also called a "molten sheet." Is called).

It is preferable that the temperature of the molten phase sheet discharged is 180 degreeC or more and 300 degrees C or less. The temperature of this molten resin is measured using the resin thermometer in the discharge port 12a part of T die 12. As shown in FIG. When the temperature of a molten phase sheet is less than 180 degreeC, since electroconductivity falls, there exists a tendency for thickness unevenness to arise by the nonuniformity of extending | stretching in an air gap. On the other hand, when the temperature of the molten phase sheet exceeds 300 ° C, the resin is deteriorated, and the discharge port 12a portion is dirty, for example, to generate a decomposition gas, resulting in a die line or the like, and thus the polypropylene resin film 25 There is a tendency for appearance defects to occur.

In addition, it is preferable that the T die 12 is free of minute steps and scratches on the channel wall surface of the molten polypropylene resin. The part (lip part) of the discharge port 12a of the T die 12 is a material having a small coefficient of friction with the molten polypropylene resin, and is made of a hard material, such as plating, coating, or the like (for example, tungsten carbide or fluorine). If the special plating is used, the radius of curvature of the distal end portion of the discharge port 12a can be reduced (the distal end portion of the discharging port 12a has a shape called a so-called sharp edge), which is preferable.

As for the tip part of the discharge port 12a of the T die 12, the sharp edge shape whose curvature radius of the opening part formed in the flow path wall surface of molten polypropylene resin is 0.1 mm or less is preferable. The radius of curvature of the tip portion of the discharge port 12a is more preferably 0.05 mm or less, and even more preferably 0.03 mm or less. By using such a T die 12, generation | occurrence | production of the "fog" in the discharge port 12a can be suppressed, and a die line can also be suppressed at the same time. For this reason, the uniformity of the external appearance of the polypropylene resin film 25 manufactured can be improved more.

However, when the radius of curvature becomes 0.01 mm or less, such an effect is improved, but the strength at the tip portion of the discharge port 12a is lowered, resulting in breakage of the discharge port 12a. It may occur.

Length from the discharge port 12a of molten resin in T-die 12, until the molten-phase sheet is pinched by the elastic roll 13 and metal roll 14 provided in the lower part. It is preferable that it is about 50-250 mm, and, as for (length of an air gap), it is more preferable that it is about 50-180 mm. When the length H of the air gap exceeds 250 mm, the cooling efficiency tends to be lowered by being exposed to air for a long time, while the orientation occurs in the air gap, and a large phase difference is produced in the produced polypropylene resin film 25. Tends to occur. The lower limit of the air gap length H depends on the size of the T die 12, the diameters of the elastic rolls 13 and the metal rolls 14, and the like.

(Elastic roll)

An elastic roll means the metal roll and rubber roll which can be elastically deformed. As the metal roll which can be elastically deformed, the elastic roll 13 of the structure shown in FIG. 4 can be used suitably. The elastic roll 13 with which the film manufacturing apparatus 100 shown in FIG. 4 is equipped is equivalent to the shaping | molding roll described in Unexamined-Japanese-Patent No. 342798, Specifically, the metal strip-shaped body of cylindrical shape ( 13a of rubber | dies (also called an endless belt), the rubber roll 13b (one in the example of FIG. 4) arrange | positioned inside the band body 13a, and the band body 13a. ) And a roll of elastically deformable metal having a liquid L filling the space between the rubber roll 13b and a temperature adjusting means (not shown) for adjusting the temperature of the liquid L.

The strip | belt-shaped body 13a is formed in cylindrical shape by the metal thin film which can be elastically deformed, such as spring steel, stainless steel, and nickel steel, and the seam does not exist in the surface. Both sides of the band-like body 13a are closed by a blocking member (not shown). As the band body 13a, the thickness is about 100-1500 micrometers, the diameter is about 200-600 mm, and surface roughness 0.5S or less can be used, Preferably surface roughness is 0.2S or less. In addition, although the diameter of the strip | belt-shaped body 13a is set to an appropriate magnitude | size according to the processing speed of the polypropylene resin film 25, when the diameter of the strip | belt-shaped body 13a is the said range, the polypropylene resin film 25 As a processing speed of), it is possible to cope with a range of several m / min to hundreds of ten m / min.

The rubber roll 13b has a circumferential shape, and is elastically deformable and rotatable inside the band-like body 13a. The rubber roll 13b can be formed of EPDM (ethylene-propylene-diene rubber), neoprene or silicone having a hardness of about 30 to 90 degrees. The diameter of the rubber roll 13b can be about 100-250 mm.

As the liquid L, water, ethylene glycol, oil, etc. can be used, for example. By controlling the temperature of the liquid L by a temperature control means (not shown), the surface temperature of the band-like body 13a is indirectly controlled.

It is preferable that the thickness of the strip | belt-shaped body 13a is about 350-500 micrometers, and the hardness of the rubber roll 13b is about 60-75. When the thickness of the band-like body 13a is less than 350 µm and the hardness of the rubber roll 13b is less than 60, the elasticity of the elastic roll 13 becomes too low to uniformly press in the width direction of the elastic roll 13. It tends to be difficult. Moreover, when the thickness of the strip | belt-shaped body 13a exceeds 500 micrometers and the hardness of the rubber roll 13b exceeds 75, the rigidity as the elastic roll 13 will become high too much, and there exists a tendency for the effect to smoothly tighten. .

Moreover, it is also preferable to use the elastic roll 16 of the structure shown in FIG. 5 as an elastic roll. The elastic roll 16 which the film manufacturing apparatus 200 shown in this figure is equipped with is equivalent to the shaping | molding belt means described in Unexamined-Japanese-Patent No. 7-40370. Specifically, the elastic roll 16 is arranged along the outer circumferential surface of the metal roll 14 in the cylindrical metal band-shaped body (also called an endless belt) 16a and the band-shaped body 16a inside. At the same time, it is an elastically deformable metal roll having two rolls 16b and 16c arranged so that the longitudinal directions thereof become parallel, and temperature adjusting means (not shown) for adjusting the surface temperature of the band-like body 16a. The roll 16b is a rubber roll, and the roll 16c is a metal roll. The surface temperature of the strip 16a is adjusted by adjusting the surface temperature of the roll 16c with a temperature adjusting means.

The strip | belt-shaped body 16a is formed in the tubular shape by the metal thin film which can be elastically deformed, such as spring steel, stainless steel, and nickel steel, and the seam does not exist in the surface. The band-like body 16a spans the rubber roll 16b and the metal roll 16c, and the tension (tension) of the band-shaped body 16a is obtained by bringing the distance between the rolls 16b and 16c close or apart. ) Can be adjusted. As the band-shaped body 16a, the thickness is about 300-800 micrometers, and when the cylindrical shape is used, the thing about 200-600 mm in diameter can be used, Preferably surface roughness is 0.2S or less.

The rolls 16b and 16c have a columnar shape, and are rotatable inside the strip-shaped body 16a. The rubber roll 16b can be formed of EPDM (ethylene-propylene-diene rubber), neoprene or silicone having a hardness of about 30 to 90 degrees. As the rolls 16b and 16c, those having a diameter of about 80 to 200 mm can be used.

When the elastic roll 16 is used, the position where the molten-phase sheet discharged from the discharge port 12a of the T die 12 is initially fitted by the band-like body 16a and the metal roll 14 becomes a starting point of the pinching pressure. The position where the pinched resin falls from the strip 16a and the metal roll 14 becomes the end point of pinching.

It is preferable that the thickness of the strip | belt-shaped body 16a is about 350-600 micrometers, and the hardness of the rubber roll 16b is about 60-80. If the thickness of the strip-shaped body 16a is less than 350 micrometers and the hardness of the rubber roll 16b is less than 60, the elasticity as the elastic roll 16 will become low too much, and it will clamp uniformly in the width direction of the elastic roll 16. It tends to be difficult to do. Moreover, when the thickness of the strip | belt-shaped body 16a exceeds 600 micrometers, and the hardness of the rubber roll 16b exceeds 80, the rigidity as the elastic roll 16 will become high too much, and a bank (resin deposition) will become difficult There exists a tendency which becomes easy to shape | mold and is easy to generate a phase difference in the polypropylene resin film 25 obtained.

Moreover, it is also preferable to use the elastic roll 17 of the structure shown in FIG. 6 as an elastic roll. The elastic roll 17 with which the film manufacturing apparatus 300 shown in FIG. 6 is equipped is equivalent to the press roll described in Unexamined-Japanese-Patent No. 11-235747. Specifically, the elastic roll 17 includes a highly rigid metal inner cylinder 17a, a thin metal outer cylinder 17b disposed outside the metal inner cylinder 17a, and a metal inner cylinder. A fluid L cylinder 17c disposed inside 17a, a space between the metal inner cylinder 17a and the thin metal outer cylinder 17b, and a liquid L filling the inside of the fluid shaft cylinder 17c; It is an elastically deformable metal roll having temperature control means (not shown) for adjusting the temperature of the liquid L.

The metal inner cylinder 17a, the thin metal outer cylinder 17b, and the fluid shaft cylinder 17c are arrange | positioned so that it may become coaxial. In the metal inner cylinder 17a, a plurality of through holes 17d are formed along the main direction thereof. As a result, the liquid L is circulated inside the elastic roll 17 in the order of the space between the fluid shaft cylinder 17c, the through hole 17d, the metal inner cylinder 17a, and the thin metal outer cylinder 17b. have.

The thin metal outer cylinder 17b is made of stainless steel or the like, and no seam is present on the surface thereof and has flexibility. In order to make the thin metal outer cylinder 17b have flexibility, flexibility, and resilience close to rubber elasticity, the thin metal outer cylinder 17b is designed to be thin within the range in which the thin cylinder theory of elastic mechanics can be applied. As the thin metal outer cylinder 17b, the thickness is about 2000-5000 micrometers, the diameter is about 200-500 mm, and surface roughness 0.5S or less can be used, Preferably surface roughness is 0.2S or less. If the thickness of the thin metal outer cylinder 17b is less than 2000 µm, the tension at the time of narrowing the molten sheet sheet by the elastic roll 17 and the metal roll 14 tends to be nonuniform. There exists a tendency for a bank to generate | occur | produce at the time of pinching the said molten-phase sheet | seat according to the thickness of the molten-sheet sheet | seat discharged from the discharge port 12a of the T die 12, and the elasticity of the outer cylinder 17b becomes large.

As the liquid L, water, ethylene glycol, oil, or the like can be used, for example. By adjusting the temperature of the liquid L by the temperature control means which is not shown in figure, the surface temperature of the thin metal outer cylinder 17b is indirectly adjusted.

Moreover, as mentioned above, a rubber roll can also be used as an elastic roll. When using a rubber roll as an elastic roll, it is preferable that the surface hardness is 65-80, and it is more preferable that it is 70-80. By using the rubber roll of such surface hardness, it becomes easy to maintain the pressure (linear pressure) applied when pinching the molten phase sheet uniformly, and also generate a bank between the metal roll 14 and a rubber roll. It becomes easy to shape a molten phase sheet, without making it become impossible. When a bank generate | occur | produces, it exists in the tendency for the phase difference of the polypropylene resin film 25 obtained to become large, and when it arrange | positions to the liquid crystal display device 1, since visibility may worsen, it is unpreferable.

When using a rubber roll as an elastic roll, it is preferable to insert a support body into the clearance gap between a molten phase sheet and a rubber roll, when pinching a molten phase sheet with a rubber roll and a metal roll. As the support, for example, a biaxially stretched film made of a thermoplastic resin can be used.

It is preferable to use the support body which is excellent in smoothness. In the molten phase sheet, the surface opposite to the surface in contact with the metal roll is pinched between the rolls in a state in contact with the support, so that the surface state of the support is transferred to the obtained polypropylene resin film 25 surface. Therefore, the surface roughness of the support body to be used is small, and the smoother the surface, the smoother the obtained surface becomes. It is preferable that the surface roughness of the support body to be used is 0.01 micrometer or more and 1.5 micrometers or less, More preferably, they are 0.01 micrometer or more and 1.0 micrometer or less. Moreover, the thickness of the support body to be used needs to be 5 micrometers or more and less than 50 micrometers, Preferably they are 10 micrometers or more and 30 micrometers or less. When the support body used is thinner than 5 micrometers, since it causes handling problems, such as being easy to wrinkle, it is unpreferable. On the other hand, when it is 50 micrometers or more, the polypropylene resin film 25 obtained by worsening the cooling efficiency of a molten-sheet sheet | seat (25 ) Is not preferable because the transparency of the deterioration. The thermoplastic resin constituting the support may be a resin which is not strongly thermally fused with a polypropylene resin. Specifically, polyester, polyamide, polyvinyl chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyacryl Nitrile and the like. Among these, polyester with few dimensional changes due to humidity, heat, or the like is most preferred.

After cooling and solidifying, the molten phase sheet clamped together with the support between the rubber roll and the metal roll is slit end as necessary in the state where the support is laminated, and then wound with a winder to wind the polypropylene resin film 25 and A laminate of the support can be obtained. It is also possible to peel a support body in front of a winder, and to wind only the polypropylene resin film 25. When peeling off the support body pinched between the rolls from the polypropylene resin film 25, after the temperature of the said polypropylene resin film 25 is cooled to 60 degrees C or less, Preferably it is 40 degrees C or less, peeling off is carried out. It is preferable. When a support body is peeled off in the state where the temperature of the polypropylene resin film 25 is high, a film may deform | transform, an orientation may arise, and a phase difference may become large.

It is preferable to use the metal roll which can be elastically deformed from the said elastic roll from the point which the smoothness of the surface which contacts an elastic roll is more excellent. It is preferable that the surface of the metal roll which can be elastically deformed is a mirror surface state.

(Metal roll)

The metal roll 14 with which the film manufacturing apparatus 100 shown in FIG. 4 (same with respect to the film manufacturing apparatuses 200 and 300 shown in FIG. 5 and FIG. 6) is equipped is a highly rigid metal outer cylinder 14a. And a fluid L cylinder 14b disposed inside the metal outer cylinder 14a, a liquid L filling the space between the metal outer cylinder 14a and the fluid shaft cylinder 14b and the inside of the fluid shaft cylinder 14b. And temperature adjusting means (not shown) for adjusting the temperature of the liquid L. FIG. A plurality of through holes 14c are formed in the fluid shaft cylinder 14b along the circumferential direction thereof. The diameter of the metal roll 14 can be about 200-600 mm. In the metal roll 14, the surface temperature of the metal outer cylinder 14a is indirectly adjusted by adjusting the temperature of the liquid L by temperature control means (not shown) like the elastic roll 13, and together with an elastic roll. The molten phase sheet discharged from the discharge port 12a of the T die 12 is cooled and solidified.

Here, when one side produces the polypropylene resin film 25 which consists of regular uneven | corrugated surface, such as a prism shape or a lens shape, either one of the said elastic roll 13 and the metal roll 14 is a transfer type | mold. It is preferable to provide a transfer die on the surface of the metal roll 14 in order to transfer the shape of the transfer die more accurately. Hereinafter, the metal roll 14 provided with the transcription | transfer mold in the surface is also called "transfer roll."

The transfer die is provided on the surface of the transfer roll, pressed against the surface of the molten phase sheet, and transferred to the molten phase sheet as its opposite shape. The transfer die consists of a plurality of recesses formed on the transfer roll surface. The shape, groove depth, pitch spacing, and the like of the recesses are determined along the surface irregularities of the desired polypropylene resin film 25. The groove of the transfer die may be parallel to the main direction of the transfer roll, may be parallel to the width direction of the transfer roll, or may be formed at a constant angle with the main direction.

As a manufacturing method of the said transfer type | mold, a well-known method can be employ | adopted. For example, after a plating treatment such as chromium plating, copper plating, nickel plating, nickel-phosphorus plating is applied to the surface of a transfer roll made of stainless steel, iron steel, or the like, a diamond bite or The method of removing a shape using a metal grindstone, laser processing, or chemical etching, and processing a shape is mentioned.

In addition, after the transfer roll is formed, the surface of the transfer roll may be subjected to plating treatment such as chromium plating, copper plating, nickel plating, nickel-phosphorus plating or the like at a level that does not impair the accuracy of the surface shape, for example. .

(Cooling roll)

The cooling roll is a roll for further cooling the molten phase sheet clamped by the elastic roll and the metal roll. The cooling roll 15 with which the film manufacturing apparatus 100 shown in FIG. 4 (same with respect to the film manufacturing apparatuses 200 and 300 shown in FIG. 5 and FIG. 6) is the same as the said metal roll 14, It has a structure, and specifically, between the highly rigid metal outer cylinder 15a, the fluid shaft cylinder 15b arrange | positioned inside the metal outer cylinder 15a, and between the metal outer cylinder 15a and the fluid shaft cylinder 15b. It has a liquid (L) filling the space and the fluid shaft cylinder (15b) and a temperature adjusting means (not shown) for adjusting the temperature of the liquid (L). A plurality of through holes 15c are formed in the fluid shaft cylinder 15b along the circumferential direction thereof. As the cooling roll 15, the mirror surface whose diameter is about 200-600 mm and whose surface roughness is 0.2S or less can be used. Also in the cooling roll 15, the surface temperature of the metal outer cylinder 15a is indirectly adjusted by adjusting the temperature of the liquid L by the temperature control means which is not shown in figure.

The polypropylene resin film 25 is produced by tightly cooling and solidifying the molten phase sheet discharged from the discharge port 12a of the T die 12 by the elastic roll and the metal roll (including the transfer roll). do. The pressure (linear pressure) to pinch is determined by the pressure which presses an elastic roll to a metal roll, It is preferable that it is 1-300 N / mm, More preferably, it is 1-200 N / mm. If the linear pressure is less than 1 N / mm, it becomes difficult to uniformly control the linear pressure to the molten phase sheet, and when the metal roll is a transfer roll, it is difficult to accurately transfer the transfer die. In addition, when the linear pressure exceeds 300 N / mm, the molten-phase sheet is pinched too strongly, so that the phase difference is large in the polypropylene-based resin film 25 obtained by forming a bank formed while the molten-sheet sheet is stacked in the pinched portion. Tends to be expressed.

As a method of controlling the linear pressure, (1) a method of adjusting the roll spacing by providing a "wedge" in the form of a triangular wedge called a coater at a portion to be pinched and adjusting the coater, and (2) an elastic roll and a metal roll It is common to pressurize both until it contacts the coater adjusted to predetermined pressure using hydraulic pressure, air, etc. In addition, the method of controlling the rotation speed of a screw without mechanically using a coater and mechanically crimping to a predetermined position and the method of using a servomotor for a hydraulic system are also mentioned.

Moreover, the distance pinched by an elastic roll and a metal roll is 1-30 mm, Preferably it is 1-15 mm. If the distance to pinch is in this range, when a metal roll is a transfer roll, a transfer die can be accurately transferred. As a method of controlling the distance to be pinched, (1) a method of adjusting the roll spacing by providing a "wedge" in the form of a triangular wedge called a coater at a portion to be pinched, and adjusting the coater, (2) elasticity of the elastic roll How to adjust is common.

Although the surface temperature of an elastic roll and a metal roll at the time of pinching a molten phase sheet is not restrict | limited, The polypropylene resin film 25 which has high transparency becomes easy to be obtained by rapidly cooling a molten phase sheet. As specific surface temperature, it is preferable that the surface temperature of at least one roll of an elastic roll or a metal roll is 0-60 degreeC, More preferably, the surface temperature of at least one roll is 0-40 degreeC, More preferably, it is at least one side The surface temperature of the roll of is 0-30 degreeC.

Moreover, the processing speed of the polypropylene resin film 25 becomes faster, so that the diameter of metal rolls, such as a transfer roll, is large. For example, when the diameter of a metal roll is 600 mm, the processing speed of the polypropylene resin film 25 can be set to about 50 m / min at maximum, and usually about 30 m / min.

The elastic rolls and the metal rolls are arranged so that they are generally lined up below the T die 12. The elastic rolls and the metal rolls are arranged at predetermined intervals, and the melt is discharged from the gap between the elastic rolls and the metal rolls, the rotational speeds of the elastic rolls, the metal rolls and the cooling rolls, and the discharge port 12a of the T die 12. The thickness of the polypropylene resin film 25 is defined according to the discharge amount of the upper sheet or the like.

The edge portion of the polypropylene resin film 25 further cooled by the cooling roll is slit (cut) as necessary, wound around a winding machine, or cut into sheets. Before or after slitting the edges of the polypropylene-based resin film 25, temporary protection to protect the surface on one or both sides of the polypropylene-based resin film 25 for a period of time until it is provided for use. You may laminate | stack a film.

By the above manufacturing method, the polypropylene resin film 25 can be manufactured. The polarizing plate 20 using the polypropylene resin film 25 is bonded to the surface of the liquid crystal cell 40, and is used as the liquid crystal panel 2. As described above, the liquid crystal panel 2 is used as the liquid crystal display device 1 by sandwiching the backlight 10, the light diffusion plate 50, or the like. The mode of the liquid crystal cell 40 to which the polarizing plate 20 is applied is not particularly limited. For example, the liquid crystal cell 40 of various modes, such as VA mode, IPS mode, and TN mode, can be used.

Yes

Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited by these examples.

Example 1

(a) Preparation of polypropylene resin film

Using the film manufacturing apparatus 200 shown in FIG. 5, the polypropylene resin film was produced in the following procedure. First, 50 mmφ extruder 11 (screw) which heated polypropylene resin A [propylene homopolymer, melt flow rate (MFR) = 7 g / 10min, melting point Tm = 164 degreeC] containing isotactic at 270 degreeC : Melt-kneaded with L / D = 32, full flight screw), and from the extruder 11 to a gear pump, an adapter and a T die 12 (all set to 270 ° C), which are installed after the extruder 11, It fed in order, and discharged the polypropylene resin sheet (molten resin) melted from the discharge port 12a (lip ball) of the T die 12. As shown in FIG. The temperature of the molten resin in the discharge port 12a part of the T die 12 was 270 degreeC. And the molten resin is pinched by the elastic roll 16 (no transfer type) and the metal roll 14 (no transfer type) under the manufacturing conditions shown in Table 1, and further cooled by the cooling roll 15, and poly A propylene resin film was produced. In addition, MFR of polypropylene resin A was measured on condition of the temperature of 230 degreeC, and load of 21.18 N according to JISK7110. In addition, melting | fusing point Tm is melting peak temperature obtained by the differential scanning calorimetry based on JISK71121.

The thickness, haze, and in-plane retardation value R ₀ of the polypropylene resin film obtained by the above method were measured by the following apparatus. As a result, the polypropylene resin film had a thickness of 107.1 μm, a haze of 1.3%, and an in-plane retardation value R ₀ of 20.6 nm. The results are shown in Table 1.

(Thickness of Polypropylene Resin Film)

The thickness of 5 points | pieces was measured using the contact thickness meter ("MS-5C" by NIKON Corporation), and the average value was made into the thickness of a polypropylene resin film.

(Haze of polypropylene resin film)

It measured using the haze meter "HM-150" type by Murakami Color Research Institute made in conformity with JIS K 7136.

(In-plane retardation value R ₀ of polypropylene resin film)

By using a phase difference measuring apparatus (manufactured by coming K soku to whether or device "KOBRA-WPR"), the in-plane retardation value R ₀ at a wavelength of 590nm was measured.

In addition, "the pinching distance" shown in Table 1 has shown the length by which molten resin is pinched between the elastic roll 16 and the metal roll 14, and pressure-reduced between the elastic roll 16 and the metal roll 14, Paper ("Prescale LLW" manufactured by FUJIFILM SUPPLIES CO., LTD.) Was sandwiched, and the distance in the MD direction of the color development portion of the pressure-sensitive paper was measured, which was defined as the narrowing distance. In addition, the used elastic roll 16, the metal roll 14, and the cooling roll 15 have the following structures.

(Elastic roll 16)

Band-like body 16a: metal, surface roughness 0.2S, thickness 300micrometer

Roll 16b: made of silicone, diameter 160 mm, hardness 60

Roll 16c: metal, 160 mm diameter

(Metal Roll 14)

Metal outer cylinder 14a: metal, diameter 300 mm

(Cooling roll 15)

Metal outer cylinder 15a: made of metal, diameter 300 mm, surface roughness 0.1 S (mirror surface)

Comparative Example 1

(b) Preparation of polypropylene resin film

The poly of Comparative Example 1 was prepared in the same manner as in Example 1 except that the manufacturing conditions (surface temperature, pinching distance, linear pressure, and line speed of the metal roll 14 and the elastic roll 16) were changed as shown in Table 1. A propylene resin film was produced. As shown in this table, the obtained film had a film thickness of 97.0 µm, a haze of 21.8%, and an in-plane retardation value R ₀ of 55.6 nm.

Manufacture conditions Film properties Metal roll
Surface temperature
℃ Elastic roll
Surface temperature
℃ Narrowing distance
mm Pressure
N / mm line
speed
m / min thickness
㎛ Hayes
% Inside
Phase difference value R ₀
nm Example 1 20 20 4 144 5.0 107.1 1.3 20.6 Comparative Example 1 10 120 10 33 2.5 97.0 21.8 55.6

(c) measurement of surface orientation parameters

The surface orientation parameters by ATR-Raman spectroscopy were measured about each of the polypropylene resin films of Example 1 and Comparative Example 1 obtained in (a) and (b). The measurement of the surface orientation parameter was performed with the following apparatus and measurement conditions.

<Measurement device>

Ramanor T-6400 (manufactured by Jobin Yvon / Atagobutane)

<Measurement Conditions>

Measurement mode: ATR Raman (Ge30 °),

Prism: High Index Glass

Incident angle: 56.5 ° (ATR), 51.0 ° (bulk)

Beam diameter: 100㎛

Light source: Ar laser / 514.5nm

Laser Power: 400mW (At Tube)

Diffraction Grating: Single 1800gr / nm

Slit: 100 μm

Detector: CCD / Jobin Yvon 1024 Channel

Number of measurements: n = 3 (Numeric data such as peak intensity uses an average value of N = 3)

<Measurement method>

The surface of the polypropylene resin film was directly pressed on a high refractive index glass prism to measure the ATR-Raman spectrum. Moreover, the penetration depth of the measurement light was computed based on the following formula. As a result, it was found that the penetration depth was about 100 nm.

Where v is the inverse of the wave number of the incident laser light (v = (1 / 514.5) = 0.001943634 ...), n _s is the refractive index of the polypropylene resin film (n _s : about 1.5), and n _p is the refractive index of the prism (n _p = 1.88: high refractive index glass), and θ is an incident angle (θ = 56.5 °).

About the polypropylene resin film of Example 1 and the comparative example 1, absorption spectrum was measured about each of parallel polarization and perpendicular polarization by said measuring apparatus and measurement conditions, and the surface orientation parameter was calculated | required. The obtained absorption spectra are shown in Fig. 7 (Example 1) and Fig. 8 (Comparative Example 1). In addition, the value of the obtained surface orientation parameter is described in Table 3.

(d) Preparation of adhesive test sample (polarizing plate)

With respect to each of the polypropylene resin films of Comparative Example 1 obtained in Example 1 and (b) obtained in the above (a), a sample for an adhesive test (peel test) was produced in the following procedure. As Example 1 and the comparative example 1, the polarizing plate which has the laminated constitution shown in FIG. 9 was used as a sample.

(1) Preparation of Polarizing Film

After immersing a polyvinyl alcohol film having a thickness of 75 µm with an average degree of polymerization of about 2400 and a saponification degree of 99.9 mol% or more in pure water at 30 ° C, the weight ratio of iodine / potassium iodide / water is 0.02 / 2/100 at 30 ° C. It was immersed. Then, it was immersed at 56.5 degreeC in the aqueous solution whose weight ratio of potassium iodide / boric acid / water is 12/5/100. Subsequently, after wash | cleaning with the pure water of 8 degreeC, it dried at 65 degreeC and obtained the polarizing film in which iodine adsorption-orientated to polyvinyl alcohol. Stretching was mainly performed in the process of iodine dyeing and a boric acid process, and the total draw ratio was 5.3 times.

(2) Preparation of adhesive

Each of the following components was mixed at a blending ratio (unit is part by weight) shown in Table 2, and then degassed to prepare a photocurable adhesive (adhesive A). In addition, the photocationic polymerization initiator (b1) was mix | blended as a 50 weight% propylene carbonate solution, and it showed in Table 2 by the solid content.

(A) epoxy compound

(a1) 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate

(a2) 1,4-butanediol diglycidyl ether

(B) photocationic polymerization initiator (it stands for "initiator" in table)

(b1) 4,4'-bis (diphenyl sulfonio) phenyl sulfide bis (hexafluoro phosphate) type | system | group photo cationic polymerization initiator ["SP-150" by ADEKA Corporation | KK)

(A) epoxy compound (B) initiator (a1) (a2) (b1) Glue A 85.0 15.0 2.25

(3) Preparation of the polarizing plate

The polypropylene resin film obtained in Example 1 or Comparative Example 1 is bonded to one side of the polarizing film so that the measurement surface of the surface orientation parameter is the polarizing film side, and the other side The 75 micrometer-thick cyclic olefin resin film ("ZEONOR" by Nihon Zeon Co., Ltd.) was bonded together using the said adhesive agent A to the following. In addition, in the bonding surface of a polypropylene resin film and a cyclic olefin resin film, a corona treatment apparatus (high frequency power supply; "CT-0212" by Kasuga Denki Co., Ltd., transmitter body; "CT-0212" by Kasga Denki Co., Ltd.) , High pressure transformer; CT-T022 manufactured by Kasuga Denki Co., Ltd., distance of 3 mm between the film surface and the electrode of the corona treatment device, output 280 W, line speed 1.0 m / min, ambient temperature 23 ° C., ambient relative humidity 55 Corona treatment was performed three times in succession under the condition of% RH. Next, the adhesive A is cured by passing it once at a line speed of 1.0 m / min in an ultraviolet irradiation device (ultraviolet lamp uses "HAL400NL" at 80 W and irradiation distance is 50 cm) manufactured by Nihon Denchi Co., Ltd. A polarizing plate was obtained.

(e) Measurement of adhesion

About each of the adhesive test samples (polarizing plate) of Example 1 and Comparative Example 1 obtained above, the 90 degree peeling test was done on the following apparatuses and conditions.

<Evaluation device>

Autograph AG-1 [manufactured by Shimadzu Sesakusho]

<Measurement Conditions>

Test speed: 300mm / min

Test piece: 200mm length * 25mm width (the cyclic olefin resin film side faces down, and sample is fixed to glass plate with pool)

<Measurement method>

As shown in FIG. 10, the edge part of the sample fixed to the glass plate was picked up, and it pulled in the vertical direction (about 90 degrees: arrow direction of drawing) with respect to a glass plate, and peeled between the polypropylene resin film and a polarizing film. The load at the time of peeling was measured with the said evaluation apparatus, and the adhesive force was evaluated.

Table 3 shows the results of the orientation parameter (surface orientation parameter) measurement and the adhesive force measurement of Example 1 and Comparative Example 1. In addition, the orientation parameter of the bulk was also described as a reference. An orientation parameter (bulk) is an orientation parameter calculated based on the Raman spectrum by Raman scattered light from the whole polypropylene resin film. This orientation parameter (bulk) has shown the molecular orientation in the whole thickness direction of a polypropylene resin film unlike the orientation parameter (ATR) which shows the molecular orientation of the surface layer vicinity.

Adhesion
[N / 25mm] Orientation parameter
(ATR) Orientation parameter
(bulk) Example 1 11.6 1.05 1.04 Comparative Example 1 0.5 1.82 1.27

From the results shown in this table, when the orientation parameter (ATR) is 1.05 as in Example 1, the adhesive force may be 11.6 N / 25 mm. On the other hand, when the orientation parameter (ATR) is 1.82 as in Comparative Example 1, the adhesive force is considerably inferior to Example 1. From these results, as shown in Example 1, it can be said that adhesive force is more favorable than the other range within the range whose surface orientation parameter is 0.95 (= 1 / 1.05)-1.05.

Claims (7)

The polypropylene resin film which has a surface whose surface orientation parameter obtained by Raman spectroscopy measurement by attenuation total reflection method exists in the range of 0.66-1.50. The polypropylene resin film according to claim 1, wherein the surface orientation parameter is in the range of 0.95 to 1.05. Polarizing film which consists of uniaxially-stretched polyvinyl alcohol-type resin film by which iodine or dichroic dye was adsorption-oriented,
The polypropylene resin film according to claim 1 laminated on the polarizing film via an adhesive layer.
As a polarizing plate to be provided,
The said polypropylene resin film is a polarizing plate laminated | stacked so that the said surface may contact the said adhesive bond layer. The polarizing plate of Claim 3 in which the said adhesive bond layer consists of hardened | cured material of the active energy ray curable resin composition containing an epoxy resin. The polarizing plate of Claim 3 further equipped with the protective film or optical compensation film laminated | stacked on the surface opposite to the surface on which the said polypropylene resin film is laminated | stacked in the said polarizing film. A liquid crystal panel provided with a liquid crystal cell and the polarizing plate of Claim 3 laminated | stacked on the said liquid crystal cell. A liquid crystal display device comprising the surface light source element and the liquid crystal panel according to claim 6.

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