KR20000011493A - Polarizing plate unit - Google Patents

Abstract

PURPOSE: A polarizing plate unit equipped with a polarizing plate and a separate film is to have the first separate film and the second separate film. CONSTITUTION: A polarizing plate unit(16) comprises: the first separate film(10) attached to one side of a polarizing plate(14) by an adherence layer(11); the second separate film(12) attached to the other side of the polarizing plate(14) by an adherence layer(8). The first and second separate films(10,12) are separated due to a low adhesive strength of the adherence layers(8,11). The polarizing plate(14) consists of the first protection film(3) and the second protection film(7). Accordingly, the protection film and the separate film for polarizing plate which has a remarkable optical characteristic due to a low optical anisotropy and interference non-uniformity are provided.

Description

Polarizing Plate Unit

The present invention relates to a polarizing plate unit having a polarizing plate and a separate film, and more particularly to a polarizing plate unit having a first separate film and a second separate film.

The polarizing plate is usually colored with a dichroic dye having a polarizing function, and is completed by sandwiching a uniaxially stretched polyvinyl alcohol film (polarizing film) with two cellulose triacetate (TAC) films, which are the first and second protective films, from both sides. do. The completed polarizing plate is shipped in the form (polarizing plate unit) which provided the separate film which can peel easily on the surface (it may be possible to re-bond after peeling). And after the shipment of a polarizing plate or a polarizing plate is received, the product inspection of a polarizing plate is performed. As a product inspection method, when a polarizing plate is orthogonal and the whole is seen in darkness, there exists a method of examining the presence and the number of the defect part which a light leaks.

Conventionally, the biaxially stretched polyethylene terephthalate (polyethylene terephthalate) film was mainly used for this separator film. In the case of using the biaxially stretched polyethylene terephthalate film-separated film, when the polarizing plate was orthogonal, the normal part was not entirely displayed in the dark, and the interference unevenness appeared strongly, which was unsuitable for inspection such as visual inspection. Therefore, there existed a problem that peeling a separate film at the time of a test | inspection and performing a complicated process of bonding a separate film again for the protection of a polarizing plate after a test | inspection.

Therefore, the subject of this invention is providing the polarizing plate unit which has the separate film which can test | inspect in the adhered state and is excellent in the workability of defect detection of a polarizing plate. Moreover, the subject of this invention is reducing the troublesome process at the time of the inspection of a polarizing plate, and increasing the freedom of process design. Moreover, the subject of this invention is providing the separate film excellent in optical characteristics, with few optical anisotropy, interference nonuniformity, etc.

Moreover, when using a film which does not have interference nonuniformity as a separate film, TAC, cast polycarbonate (PC), polyether sulfone (PES), etc. are mentioned as an example, However, these are expensive and are cheaper and optically There was a demand for a film having excellent properties and easy handling.

1 is a cross-sectional view of a polarizing plate unit having a first separate film and a second separate film.

<Summary of invention>

1. A polarizing film having a first surface and a second surface, a first protective film provided on a first surface of the polarizing film, a second protective film provided on a second surface of the polarizing film, and provided on the first protective film. A polarizing plate unit having a polarizing plate comprising a first separate film and a second separate film provided on the second protective film, wherein an orientation angle of the first separate film and / or the second separate film is 80 degrees or more.

2. The polarizing plate unit according to item 1, wherein the first separator film and / or the second separator film is a resin film stretched 1.0 to 2.5 times in one direction and stretched 2.5 to 7.0 times in a direction orthogonal thereto. .

As polarizing plate unit of 3.1, the absolute value of the difference of the refractive index of a longitudinal direction of a said 1st separate film and / or the said 2nd separate film and a transverse refractive index is 0.02 or more.

4. Polarizing plate unit of 1 WHEREIN: The surface specific resistance in 23 degreeC and 25% RH of the said 1st separator film and / or the said 2nd separator film is 1x10 <^12> /? Or less.

5. The polarizing plate unit according to item 1, wherein the first separator film and / or the second separator film is a resin film heat-set in a temperature range of (Tm-150) to (Tm-25) ° C.

6. The polarizing plate unit according to item 1, wherein the first separator film and / or the second separator film have a phase difference of 50 nm or more and a deviation of 50 nm or less.

7. The polarizing plate unit according to item 1, wherein the first separator film and / or the second separator film has a haze of 80% or less in terms of 80 µ.

8. The polarizing plate unit according to 8. 1, wherein the first and second separator films have a tear strength of 40 g or more in terms of 80 µ.

9. The polarizing plate unit according to 9. 1, wherein the first separator film and / or the second separator film has a tensile strength of 13 kg / mm 2 or more.

The polarizing plate unit according to 10. 1, wherein the first separator film and / or the second separator film has a coefficient of kinetic friction of 0.40 or less.

The polarizing plate unit according to 11.1, wherein the difference between the orientation angles of both ends and the center portion of the first and / or second separator films is 0 to 10 degrees.

12. The polarizing plate unit described in 1 .1, wherein the first separator film and / or the second separator film have a heat shrinkage at 80 ° C. for 30 minutes in 5% or less in both longitudinal and transverse directions.

13. The polarizing plate unit according to item 1, wherein the first separator film and / or the second separator film is at least one selected from a polypropylene film, a polystyrene film, a polyethylene film, and a polyester film.

The polarizing plate unit according to 14. 2, wherein the first separator film and / or the second separator film is at least one selected from polypropylene film, polystyrene film, polyethylene film, and polyester film.

Other embodiments will be described below.

A protective film and a separate film are bonded to one side of a polarizer and a polarizing plate on which both surfaces are covered with a protective film, and the protective film and / or the separate film are surfaces of polyester films stretched and formed only in one direction. There is this protected polarizer.

A protective film and a separate film are bonded to one side of a polarizer and a polarizing plate whose both surfaces are covered with a protective film, and the protective film and / or the separate film have a draw ratio of 1.0 to 2.0 times in one direction, and There exists a polarizing plate in which the surface ratio which is a polyester film in which the draw ratio of the direction orthogonal to and is biaxially stretched-film-formed at 2.5-7.0 times is protected.

A protective film and a separate film are bonded to one side of a polarizer and a polarizing plate whose both surfaces are covered with a protective film, and the protective film and / or the separate film have a stretching ratio in the longitudinal direction of 1.0 to 2.0 times and transverse There exists a polarizing plate with which the surface which is a polyester film biaxially stretched-film-formed at the draw ratio of 2.5-7.0 times in the direction is protected.

A protective film and a separate film are bonded to one side of a polarizer and a polarizing plate whose both surfaces are covered with a protective film, and the protective film and / or the separate film have a refractive index in the transverse direction (nTD) and a longitudinal refractive index. There is a polarizing plate whose surface is a polyester film whose absolute value | nTD-nMD | of the difference of (nMD) is 0.03 or more.

The surface resistivity of the protective film and / or the separate film at 23 ° C., 25% RH is 1 × 10 ¹² Ω /? There exists a polarizing plate in which the said surface below is protected.

A protective film and a separate film are bonded to one side of a polarizer and a polarizing plate whose both surfaces are covered with a protective film, and the protective film and / or the separate film are surfaces of polyester films stretched and formed only in one direction. There is this protected polarizer.

It was found that the above film had no optical anisotropy and was superior in optical properties as compared with the biaxially stretched polyester film that has been used so far. As a result, when used as a 3rd protective film and / or a separate film of a polarizing plate, in the state which orthogonally crossed the polarizing plate (Cross Nicole state), the leakage of light in the whole dark is small, and the interference nonuniformity occurrence of light Since it is very small, it is possible to test, without peeling a 3rd protective film and a separate film, without peeling, and it turned out that workability was excellent in the bright point foreign material failure test etc. at the time of a product inspection.

<Embodiment of invention>

Hereinafter, the present invention will be described in detail.

The structural example of the polarizing plate unit which concerns on this invention is demonstrated using FIG. The polarizing plate unit which concerns on this invention is not limited to the structure shown in FIG.

The structure shown in FIG. 1 is an example of the polarizing plate unit which has a 1st separate film and a 2nd separate film. In the polarizing plate unit 16 of FIG. 1, the first separate film 10 is adhered to one side of the polarizing plate 14 by the adhesive layer 11, and the adhesive layer 8 is attached to the other side of the polarizing plate 14. The 2nd separate film 12 is adhere | attached by this. Since the adhesive force of the adhesion layers 8 and 11 is comparatively weak, the 1st separator film 10 and the 2nd separator film 12 can be peeled.

The configuration of the polarizing plate 14 will be described below. The first protective film 3 is adhered to one side of the polarizing film 5 by the adhesive layer 4 having a stronger adhesive force than that of the adhesive layer 8, and on the other side of the polarizing plate 14, the polarizing film ( The second protective film 7 is bonded to the other side of 5) by the adhesive layer 6.

When the first separator film 10 is provided on the side opposite to the surface on which the polarizing plate is bonded to the liquid crystal cell, the adhesive layer 11 remains on the first protective film 3 when the first separator film 10 is peeled off. It is desirable to avoid.

The first protective film 3 and the second protective film 7 preferably have the same material and thickness. Moreover, you may provide an antistatic layer, a protective layer, etc. further on the 1st protective film 3 and the 2nd protective film 7, and may provide an adhesive layer and an adhesion layer on it. Moreover, you may provide an antistatic layer, a protective layer, etc. on the 1st separator film 10 and the 2nd separator film 12. FIG. Moreover, you may take the structure which the adhesion layer 8 remains after peeling the 1st separator film 10 and the 2nd separator film 12. FIG. In this case, the adhesion layer 8 is made into the two-layered constitution of an adhesion layer (for example, 2nd separator film side) and an adhesion layer (for example, 2nd protective film side), or the material of the adhesion layer 8 is peeled off. The remaining material may be considered afterwards. When an adhesion layer remains after peeling a separator film, it can adhere to a liquid crystal cell by the adhesion layer which remained.

In addition, when the adhesive layer remains after peeling, the adhesive force is preferably 400 to 1000 g / 25 mm in the method described in JIS Z 0237, and when the adhesive layer does not remain after peeling, the adhesive force is 10 to 100 g / It is preferred that it is 25 mm.

The first protective film 3 and the second protective film 7 may be provided on the polarizing film 5 by lamination or may be provided by coating without providing the adhesive layers 4 and 6. Moreover, you may provide the 1st separator film 10 to the 1st protective film 3 by lamination, or may be provided by application | coating. Moreover, the 2nd separate film 12 may also be provided in the 2nd protective film 7 by lamination, or may be provided by application | coating. Moreover, you may provide a separate film without providing an adhesion layer. The preferable adhesive force in that case is also as mentioned above.

Each film and each layer is demonstrated.

The separate film satisfies the condition that the orientation angle is 80 degrees or more. Moreover, it is preferable that orientation angles are 80 degrees or more and 90 degrees or less, and it is more preferable that orientation angles are 82 degrees or more and 90 degrees or less. Orientation angle is the dimension which measured the orientation of the crystallized and immobilized polymer molecule at the time of extending | stretching and heat setting of a film by the polarization, and puts a sample between two polarizing plates, and measures the intensity of the light which permeates, and various apparatuses It can be measured easily.

Generally this orientation angle becomes the largest in resin film center part and edge part, such as a polyester film formed into a film, and it is especially preferable for the resin film as the separator film of this invention that this difference is small. In the present invention, the separator film preferably has a difference in the orientation angles of both ends and the center portion of the film from 0 to 10 degrees, more preferably 0 to 5 degrees, and more preferably 0 to 3 degrees.

The measurement of the orientation angle was performed as follows.

After film formation, the film was measured using a "automatic birefringence meter" (model KOBURA-21DH of Shin-Oji Paper Co., Ltd.) at 360 wavelengths at a measurement wavelength of 590 nm for 360 degrees, and an orientation angle (inclination of the optical principal axis: Incline )

It is preferable that the resin film used as a separator film of this invention contains at least 1 sort (s) of polypropylene, polystyrene, polyethylene, and polyester. Or at least 1 sort (s) of a polypropylene film, a polystyrene film, a polyethylene film, and a polyester film may be sufficient. In particular, the resin film containing polyester, especially the film which has a polyester component 50 weight% or more are preferable. Moreover, the polyester film itself may be sufficient. Although the polyester which comprises a polyester film is not specifically limited, The polyester which has film formability which uses a dicarboxylic acid component and a diol component as a main structural component is preferable.

As the dicarboxylic acid component of the main constituent components, terephthalic acid, isophthalic acid, phthalic acid, 2,6 naphthalenedicarboxylic acid, 2,7 naphthalenedicarboxylic acid, diphenylsulfondicarboxylic acid, diphenyl ether dicarboxylic acid , Diphenyl ethanedicarboxylic acid, cyclohexanedicarboxylic acid, diphenyldicarboxylic acid, diphenylthioetherdicarboxylic acid, diphenylketone dicarboxylic acid, phenyl indane dicarboxylic acid, etc. are mentioned. have. Moreover, as a diol component, ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexane dimethanol, 2, 2-bis (4-hydroxyphenyl) propane, 2, 2-bis (4-hydroxyethoxyphenyl) propane, Bis (4-hydroxyphenyl) sulfone, bisphenol fluorene dihydroxy ethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol, etc. are mentioned.

Among polyesters having these as main constituents, terephthalic acid and / or 2,6naphthalenedicarboxylic acid as dicarboxylic acid components and ethylene glycol and / or diol components as diol components in terms of transparency, mechanical strength, dimensional stability, etc. Preference is given to polyesters having ethylene glycol as the main constituent. Among them, polyesters mainly composed of polyethylene terephthalate or polyethylene 2-6 naphthalate and copolyesters composed of terephthalic acid, 2-6 naphthalenedicarboxylic acid and ethylene glycol, and a mixture of two or more kinds of these polyesters Polyester which makes a component is preferable.

If it contains 70 weight% or more of ethylene terephthalate units or ethylene 2-6 naphthalate units with respect to polyester, the film excellent in transparency, mechanical strength, dimension stability, etc. can be obtained.

As for the polyester which comprises the polyester film of this invention, another copolymerization component may be copolymerized as long as it is a range which does not impair the effect of this invention, and other polyester may be mixed. As an example of these, the dicarboxylic acid component and diol component which were illustrated above, or polyester which consists of them are mentioned.

The polyester constituting the polyester film of the present invention includes an aromatic dicarboxylic acid having a sulfonate group or an ester forming derivative thereof, a dicarboxylic acid having an polyoxyalkylene group or an ester forming derivative thereof, and a polyoxyalkylene group. You may copolymerize diol etc. which have. In view of the polymerization reactivity of the polyester and the transparency of the film, 5-sodium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 4-sodium sulfophthalic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid and their Compounds in which sodium is substituted with other metals (e.g., potassium, lithium, etc.) and ammonium salts, phosphonium salts, or ester-forming derivatives thereof, polyethylene glycol, polytetramethylene glycol, polyethylene glycol-polypropylene glycol copolymers and the like Preferred are compounds carboxylated by a method such as oxidizing a hydroxyl group at both ends. Moreover, in order to improve the heat resistance of a film, the compound which has a bisphenol type compound, a naphthalene ring, or a cyclohexane ring can be copolymerized.

The polyester used for this invention may contain antioxidant. In particular, the effect becomes remarkable when the polyester contains a compound having a polyoxyalkylene group. The kind of antioxidant to contain is not specifically limited, Various antioxidant can be used, For example, antioxidant, such as a hindered phenol type compound, a phosphite type compound, and a thioether type compound, is mentioned. . Especially, the antioxidant of a hindered phenol type compound is preferable at the point of transparency. Content of antioxidant is 0.01 to 2 weight% normally with respect to polyester, Preferably it is 0.1 to 0.5%.

If necessary, the polyester film of the present invention can also be given an active activity. Although it does not specifically limit as this activity provision means, The external particle addition method which adds inert inorganic particle to polyester, The internal particle precipitation method which precipitates the catalyst added in the synthesis | combination of polyester, The method of apply | coating surfactant etc. to the film surface Etc. are common.

The synthesis | combining method of polyester which is a raw material of the polyester film of this invention is not specifically limited, It can manufacture according to the manufacturing method of conventionally well-known polyester. For example, a direct esterification method in which a dicarboxylic acid component is directly esterified with a diol component, a dialkyl ester is first used as a dicarboxylic acid component and transesterified with the diol component, which is then subjected to reduced pressure. The transesterification method which superposes | polymerizes by heating and removing excess diol component can be used. At this time, if necessary, a transesterification catalyst or a polymerization reaction catalyst may be used or a heat stabilizer may be added. Moreover, you may add a coloring inhibitor, antioxidant, a crystal nucleating agent, a lubricating agent, a stabilizer, an antiblocking agent, a ultraviolet absorber, a viscosity modifier, an antifoamer, a transparent agent, an antistatic agent, a pH adjuster, dye, a pigment, etc. in each process at the time of synthesis | combination.

<Definition of Glass Transition Temperature Tg, Crystallization Temperature Tc, and Melting Point Tm of the Present Invention>

10 mg of film or pellets are melted at 300 ° C. in a 300 ml nitrogen stream every minute and immediately quenched in liquid nitrogen. This quench sample is set in a differential scanning calorimeter (manufactured by Rika Denki Co., Ltd., DSC 8230 type), and heated up at a temperature increase rate of 10 ° C per minute in a nitrogen stream of 100 ml per minute, and Tg, Tc, and Tm are detected. Tg was the average value between the temperature at which the baseline began to slope and the temperature newly returned to the baseline, Tc was the peak temperature of the exothermic peak, and Tm was the peak temperature of the endothermic peak. Measurement start temperature shall be 50 degreeC or more lower than Tg measured.

As for the separator film of this invention, the resin film which carried out the film-forming of the draw ratio of one direction to 1.0-2.5 times, and the draw ratio of the direction orthogonal to it is 2.5-7.0 times is preferable. More preferably, it is the resin film which carried out the film-forming of the draw ratio of the longitudinal direction in 1.0-2.5 times, and the draw ratio of the lateral direction in 2.5-7.0 times.

More preferably, it is the resin film which carried out the film-forming of the draw ratio of 1.0-1.8 times, and the draw ratio of the direction orthogonal to it to 3.5-6.0 times in one direction. More preferably, it is the resin film which carried out the film-forming of the draw ratio of 1.0-1.8 times in the longitudinal direction, and 3.5-6.0 times the draw ratio in the lateral direction.

More preferably, it is the resin film which carried out the film-forming of the draw ratio in one direction of 1.0 to 1.1 times, and the draw ratio of the direction orthogonal to it to 3.5 to 6.0 times. More preferably, it is the resin film which carried out the film-forming of the draw ratio of 1.0-1.1 times in the longitudinal direction, and 3.5-6.0 times of the draw ratio in the lateral direction.

In order to obtain the said resin film, Especially preferably, a polyester film, it can carry out by a conventionally well-known method, It does not specifically limit but can carry out by the following method. In this case, a longitudinal direction means the film forming direction (length direction) of a film, and a horizontal direction means the direction perpendicular to the film forming direction of a film. An example of the manufacturing method of a polyester film is described below.

First, polyester as a raw material is molded into pellets, hot-air dried or vacuum dried, and then melt-extruded to extrude from a T die into a sheet, closely adhered to a cooling drum by an electrostatic application method, and cooled to solidify the unstretched sheet. Get Subsequently, the obtained non-stretched sheet is heated in a range of Tg + 100 ° C. at the glass transition temperature (Tg) of the polyester through a plurality of roll groups and / or heating devices such as infrared heaters, and then subjected to one or several step species. It is a way of drawing.

In the present invention, the stretching ratio in the longitudinal direction is preferably 1.0 to 2.0 times, more preferably 1.0 to 1.8 times. More preferably, it is 1.0 to 1.1 times.

Subsequently, the longitudinally stretched polyester film obtained as described above is transversely stretched in the temperature range of Tm-20 占 폚 to Tg and then heat set. In the present invention, the stretching ratio in the transverse direction is preferably 2.5 to 7.0 times, more preferably 3.0 to 6.0 times, still more preferably 4.0 to 6.0 times.

In the case of lateral stretching, when the lateral stretching is performed while the temperature difference is sequentially raised in a range of 1 to 50 ° C. in the stretching region divided into two or more, the physical property distribution in the width direction can be reduced. In addition, when the film is held for 0.01 to 5 hours after the transverse stretching in the range of Tg 40 ° C. or higher at the final transverse stretching temperature or lower, the physical property distribution in the width direction can be further reduced, which is preferable.

The heat setting is preferably higher than the final transverse stretching temperature, and heat setting is usually performed for 0.5 to 300 seconds within the temperature range of Tm 150 ° C to Tm 25 ° C. The heat setting temperature is more preferably in the temperature range of Tm 140 ° C to Tm 60 ° C, and more preferably in the temperature range of Tm 130 ° C to Tm 70 ° C. At this time, it is more preferable to heat-set while raising a temperature difference sequentially in the range of 1-100 degreeC in the area | region divided into two or more.

The heat-fixed film is usually cooled to Tg or less, and is cut by winding the clip holding portions at both ends of the film. At this time, it is preferable to perform 0.1 to 10% relaxation treatment in the transverse direction and / or the longitudinal direction within the temperature range below the final heat setting temperature and Tg or more. Moreover, it is preferable to cool slowly to cooling Tg from the final heat setting temperature at the cooling rate of 100 degrees C or less every second. The cooling and relaxation treatment means is not particularly limited and can be performed by conventionally known means, but it is particularly preferable to perform these treatments while sequentially cooling in a plurality of temperature ranges in view of improving the dimensional stability of the film. In addition, a cooling rate is the value calculated | required by (Tl-Tg) / t, when letting time until T1 and a film reach Tg from a final heat setting temperature as final heat setting temperature is t.

Since more preferable conditions of these heat setting conditions, cooling, and relaxation processing conditions differ with the polyester which comprises a film, what is necessary is just to determine by measuring the physical property of the obtained biaxially stretched film and adjusting suitably to have a preferable characteristic.

Moreover, in the said film manufacture, you may apply functional layers, such as an antistatic layer, an active layer, an adhesive layer, a barrier layer, before extending | stretching and / or after extending | stretching. At this time, various surface treatments, such as a corona discharge treatment and a drug treatment, can be performed as needed. Clip-holding portions at both ends of the cut film are pulverized or, if necessary, subjected to granulation treatment, polymerization dismantling and repolymerization, or the like. You may reuse as a raw material. The above film forming method can be applied in addition to polyester.

Moreover, with respect to the refractive index of a plane direction, in a separate film, the absolute value | nTD-nMD | of the difference between the refractive index nMD of a longitudinal direction, and the refractive index nTD of a horizontal direction is 0.02 or more. More preferably, it is 0.03 or more, More preferably, it is 0.04 or more, More preferably, it is 0.05 or more.

Moreover, as for a separate film, it is preferable that the heat shrink rate in 80 degreeC and a 30 minute process is 5% or less in both a longitudinal and a lateral direction. More preferably, it is 2% or less in both a longitudinal and a lateral direction, More preferably, it is 1% or less in both a longitudinal and a lateral direction.

It is preferable that a phase difference of a separate film is 50 nm or more, and it is preferable that a deviation is 50 nm or less further. Moreover, it is preferable that phase difference is 50-500 nm. More preferably, it is 100-400 nm. It is preferable that there is no deviation, but it is substantially 50 nm or less, preferably 40 nm or less.

The retardation was measured under the condition of 23 ° C. and 55% RH using an automatic birefringence meter KOBRA-21DH (manufactured by KS Systems Co., Ltd.). Ten were measured and expressed as the average value. Deviation is expressed as the difference between the maximum and minimum values.

Moreover, it is preferable that the haze converted into a thickness of 80 micrometers is 0.6% or less. More preferably, it is 0.5% or less, More preferably, it is 0.4% or less. More preferably, it is 0.3% or less. The lower the value of the haze is, the more preferable it is, but about 0.1% is the lower limit.

The haze was measured using a haze system (for example, 1001DP type, manufactured by Nippon Denshoku Kogyo Co., Ltd.). The measurement result was converted into the haze value in case film thickness is 80 micrometers.

The separator film preferably has a tear strength of 40 g or more in terms of a thickness of 80 µm. More preferably, it is 45 g or more, More preferably, it is 50 g or more. Although larger tear strength value is so preferable, about 100 g is an upper limit according to manufacturing conditions.

The tear strength is obtained by weighting a sample cut to 50 mm x 64 mm according to ISO6383 / 2-1983. It measures in the casting | flow_spread direction of a film and the direction perpendicular | vertical to it, and makes these average values the tear strength. From the measurement result, it converted into the tear strength in case the thickness of a film is 80 micrometers.

It is preferable that the separator film has a tensile strength of 13 kg / mm 2 or more. More preferably, it is 13.5 kg / mm <2> or more, More preferably, it is 14 kg / mm <2> or more. Most preferably, it is 15 kg / mm <2> or more. Although the value of tensile strength is so preferable that it is large, about 50 kg / mm <2> is an upper limit according to manufacturing conditions.

Tensile strength is obtained by weighting the sample cut to 50 mm x 64 mm according to ISO6383 / 2-1983. It measures in the casting direction of a film and the direction perpendicular | vertical to it, and makes these average values the tensile strength. From the measurement result, it converted into the tensile strength in the case where the thickness of a film is 80 micrometers.

Moreover, it is preferable that a separator coefficient has a dynamic friction coefficient of 0.40 or less. More preferably, it is 0.35 or less, More preferably, it is 0.30 or less. Most preferably, it is 0.25 or less. Although the value of a dynamic friction coefficient is so preferable that it is low, about 0.10 is a lower limit from manufacturing conditions etc. The dynamic friction coefficient can be easily measured using an iron ball in accordance with the methods specified by JIS and ASTM.

The thickness of the separator film of the present invention is preferably 10 to 100 µm, particularly preferably 20 to 60 µm, more preferably 20 to 50 µm.

Film used for the separator film of this invention Especially preferably, Tg of a polyester film is 50 degreeC or more, More preferably, 60 degreeC or more is preferable. Tg is calculated | required as an average value of the temperature which the baseline measured with the differential scanning calorimeter starts to incline, and the temperature which returns to a baseline newly.

In the present invention, the surface of the separate film preferably has conductivity, and the surface specific resistance (23 ° C., 25% RH) is preferably 1 × 10 ¹² Ω /? Or less. More preferably, it is 1x10 <^{11> (} ohm) /? Or less, More preferably, it is 1x10 <^{10> (} ohm) /? Or less.

In the present invention, the conductivity is not particularly limited, but may be formed by containing a hygroscopic material or a conductive material. As a substance which gives these conductivity, surfactant, a conductive polymer, an inorganic metal oxide are mentioned, for example.

Surfactants that can be used may be any of anionic, cationic, amphoteric and nonionic. As anionic surfactant, for example, alkyl carboxylate, alkyl sulfonate, alkylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl sulfate ester, alkyl phosphate ester, N-acyl-N-alkyl tauric acid ester, sulfosuccinic acid ester It is preferable to include acidic groups, such as a carboxy group, a sulfo group, a phospho group, a sulfuric acid ester group, and a phosphate ester group, such as these, a sulfoalkyl polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl phosphate ester.

As the cationic surfactant, for example, alkylamine salts, aliphatic or aromatic quaternary ammonium salts, heterocyclic quaternary ammonium salts such as pyridinium and imidazolium and phosphonium or sulfonium salts containing aliphatic or heterocycles This is preferred.

As the amphoteric surfactant, for example, amino acids, aminoalkylsulfonic acids, aminoalkylsulfuric acids or phosphate esters, alkylbetaines, amine oxides and the like are preferable.

As the nonionic surfactant, for example, saponins (steroids), alkylene oxide derivatives (for example, polyethylene glycol, polyethylene glycol / polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkylaryl ethers, polyethylene glycol esters) , Polyethylene glycol sorbitan esters, polyalkylene glycol alkylamines or amides, polyethylene oxide adducts of silicone), glycidol derivatives (e.g. alkenylsuccinic acid polyserides, alkylphenol polyglycerides), polyvalent Alkyl esters, such as alcohol fatty acid ester, are preferable.

The conductive polymer is not particularly limited, and any anionic, cationic, amphoteric or nonionic one may be used, but preferred are anionic and cationic. More preferably, they are sulfonic acid type, carboxylic acid type in anionic, tertiary amine type, quaternary ammonium type polymer or latex in cationic.

These conductive polymers are, for example, anionic polymers or latexes described in Japanese Patent Application Nos. 52-25251, 51-29923, 60-48024, Specialty 57-18176, 57-56059, Cationic polymers or latexes described in US Pat. No. 58-56856, US Pat. No. 4,118,231, and the like.

Although the cellulose triacetate is mainly used for the film used as the 1st, 2nd protective film which protects both surfaces of the polarizing film of this invention, It is not specifically limited, Cellulose, such as cellulose diacetate, cellulose acetate butyrate, cellulose propionate, etc. An ester, a polycarbonate film, a norbornene-based resin film, a polystyrene film, a syndiotactic polystyrene film, a polyester film, a polyarylate film, and the like can also be applied. Although the thickness is not specifically limited, 10-500 micrometers, especially 25-300 micrometers are preferable for a functional and easy handling. A protective film may contain a ultraviolet absorber, a plasticizer, a lubricating agent, a mat agent, etc. according to the objective.

Moreover, it is preferable that retardation of a 1st, 2nd protective film is 30 nm or less. Moreover, it is preferable that the dimension shrinkage rate after heat-processing at 90 degreeC for 60 hours is 0.06% or less--0.06% or more.

The manufacturing method of the polarizing film and protective film of this invention is not specifically limited, It can manufacture by a general method. For example, there exists a method of bonding to a polarizing film both surfaces which alkali-treated a cellulose triacetate film and immersing and extending a polyvinyl alcohol film in the iodine solution using the fully saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, the easy adhesion processing methods described in Japanese Patent Application Laid-Open Nos. 6-94915 and 6-118232 may be used.

As an adhesive agent used for bonding the 1st, 2nd protective film process surface of this invention, and a polarizing film, For example, polyvinyl alcohol adhesives, such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes, such as butyl acrylate Etc. can be mentioned. Moreover, it is preferable to bond together so that the extending | stretching direction at the time of polarizing film preparation, and the lateral extending | stretching direction of a 1st, 2nd protective film and a separate film go straight.

<Example>

Hereinafter, although an Example demonstrates this invention further more concretely, embodiment of this invention is not limited to these.

<Example 1>

[Production of Separate Film] (Production of Polyethylene Terephthalate Film No.1)

To 100 parts by weight of dimethyl terephthalate, 65 parts by weight of ethylene glycol, and 2 parts by weight of diethylene glycol, 0.05 parts by weight of magnesium acetate hydrate was added as a transesterification catalyst, and a transesterification reaction was carried out according to a conventional method. 0.05 weight part of antimony trioxide and 0.03 weight part of trimethyl phosphates were added to the obtained product. Subsequently, the mixture was gradually heated and depressurized to polymerize at 280 ° C and 0.5 mmHg to obtain polyethylene terephthalate having an intrinsic viscosity of 0.70.

The polyethylene terephthalate was then vacuum dried at 150 ° C. for 8 hours, melt extruded at 285 ° C. using an extruder, adhered to the 30 ° C. cooling drum with electrostatic application, and cooled and solidified to obtain an unstretched sheet. This unstretched sheet was stretched 1.2 times in the longitudinal direction at 85 ° C. using a roll type drawing machine. The temperature difference between front and back was within 5 degreeC.

The obtained uniaxially stretched film was stretched 4.5 times in the transverse direction at 95 ° C using a tenter-type transverse stretching machine. Then heat treated at 70 ° C. for 2 seconds, again heat fixed at 150 ° C. for 10 seconds in the first heat fixation zone, heat fixed at 180 ° C. for 15 seconds in the second heat fixation zone, and then transverse (width) at 160 ° C. It relaxed and wound in the direction, and produced the biaxially stretched polyethylene terephthalate (polyethylene terephthalate) film No. 1 of length 1500mm of a lateral direction, and 40 micrometers in thickness.

(Production of polyethylene terephthalate films No. 2 to 9)

Polyethylene terephthalate films No. 2 to 9 were produced in a similar manner except that the longitudinal and lateral stretching ratios were prepared as shown in Table 1 at the time of film formation of polyethylene terephthalate film No. 1.

(Production of Polyethylene Terephthalate Film Nos. 10 to 12)

Except for producing polyethylene terephthalate film No. 1, the film was not stretched in the longitudinal direction (and thus the stretching ratio in the longitudinal direction was 1.0 times), except that it was produced by changing the stretching ratio as shown in Table 1 only in the transverse direction. In the same manner, Nos. 10 to 12 were produced.

[Production of Polarizing Film and Protective Film]

A polyvinyl alcohol film having a thickness of 120 μm was immersed in an aqueous solution containing 1 part by weight of iodine, 2 parts by weight of potassium iodide, and 4 parts by weight of boric acid, and stretched 4 times at 50 ° C. to prepare a polarizing film.

Konica TAC film having a thickness of 80 µm (Konica Taek KC80UVS was alkali treated with a 40 N 2.5 N sodium hydroxide aqueous solution for 60 seconds, washed again and dried to obtain an alkali treated TAC film).

On both sides of the polarizing film film, an alkali-treated surface of the TAC base was bonded on both sides using a 5% aqueous soap-type polyvinyl alcohol solution as an adhesive to prepare a polarizing plate.

[Production of Polarizing Plate Sample Nos. 1 to 12]

After performing light adhesion processing to one side of the polarizing plate produced above, the said polyethylene terephthalate film No. 1 was bonded as a separate film. After similarly performing adhesive processing on the opposite surface of a polarizing plate, the said polyethylene terephthalate film No. 1 was bonded as a separate film.

At this time, it bonded together so that the extending | stretching direction at the time of polarizing film preparation and the lateral stretching direction of a polyethylene terephthalate film may orthogonally cross. Similarly, polyethylene terephthalate films Nos. 2 to 12 were bonded together on both sides of the polarizing plates, and polarizing plate samples Nos. 1 to 12 were produced.

The polarizing plate samples No. 1 to 12 produced as described above were evaluated as described below. The results are shown in Table 1.

(Assessment Methods)

<Measurement of Refractive Index>

The refractive index of the produced polyethylene terephthalate film was measured using an Abbe refractometer (4-T) manufactured by Atago. From this value, the difference nTD-nMD between the transverse refractive index nTD and the longitudinal refractive index nMD was obtained.

<Measurement of cross nicol concentration>

Two samples were piled up so that the optical axis of a polarizing plate might be orthogonal (cross nicol state), and the optical density was measured using the densitometer (DM500 by the Dainippon screen manufacturer). The higher the optical density in the cross nicol state, the easier the spot failure at the time of inspecting the product of the polarizing plate is and the better the workability is. As optical density, it is preferable that it is 3.0 or more.

<Evaluation of interference nonuniformity>

Two samples were superimposed so that the optical axis of a polarizing plate might be orthogonal (cross nicol state), it was placed on an observation table, and the interference nonuniformity seen on a polarizing plate was visually observed. The occurrence of interference non-uniformity interferes with the inspection of the foreign matter on the bright spot of the polarizing plate, and the less, the better the workability during product inspection.

A: The interference nonuniformity is not seen at all.

B: Slight interference interference is seen, but no problem

C: Difficult to work due to many interference unevenness

If it is B or higher, it is a problem without problem.

As can be seen from Table 1, it was found that when the polyester film of the present invention was used as the separator film of the polarizing plate, the optical properties were excellent and the workability of failure detection during product inspection was excellent.

<Example 2>

Polarizing plate samples No. 13 to 15 were produced in the same manner except that the following conductive layer was applied to the opposite side to the surface to be bonded to the polarizing plate of polyethylene terephthalate film No. 1 prepared in Example 1.

[Application of Conductive Layer]

After apply | coating an auxiliary layer to polyethylene terephthalate film No. 1, the following conductive layer was apply | coated.

(Secondary layer)

An acrylic copolymer latex (30 wt% butyl acrylate / 20 wt% t-butyl acrylate / 25 wt% hydroxyacrylate / 25 wt% styrene) was applied to a thickness of 0.2 탆.

(Conductive layer)

Samples Nos. 12 to 14 were prepared by coating the following conductive layers on the auxiliary layer, respectively.

Sample 13

3.1 g of compound (A)

0.2 g of compound (B)

0.3 g of compound (C)

0.1 g of silica fine particles (2-3 μm)

Quantity to become 1000 ml of distilled water

The processing liquid was applied to a thickness of 0.1 mu m.

Sample 14

23.0 g of compound (D)

50.0 g of compound (E) (solid content 20% latex liquid)

5.0 g of compound (F)

0.1 g of compound (G)

Quantity to become 1000 ml of distilled water

The processing liquid was applied to a thickness of 0.5 mu m.

Sample 15

200 g equivalent of tin oxide sol dispersion liquid (manufactured by Takasaki Chemical Co., Ltd.)

10.0 g of gelatin

0.1 g of compound (G)

0.8 g of hexamethylene-1,6-bis (ethyleneurea)

Quantity to become 1000 ml of distilled water

The processing liquid was applied to a thickness of 0.2 탆.

Evaluation described below was performed about polarizing plate sample No. 1 and the polarizing plate sample numbers 13-15 produced as mentioned above. The results are shown in Table 2.

(Assessment Methods)

<Measurement of surface specific resistance>

For polarizing plate samples 1 and 13 to 15, moisture was adjusted for 24 hours under the conditions of 23 ° C. and 25% RH, and then applied to a voltage of 100 V using a terahometer (VE-30) manufactured by Kawaguchi Denki Corporation under the same conditions. Surface resistivity was measured.

<Dust adhesion test>

The following dust adhesion performance evaluation was performed about the polarizing plate samples 1 and 13-15. After controlling the humidity for 24 hours at 23 ° C. and 25% RH, the surface of the sample was rubbed several times with a rubber roller under the same conditions, and the cigarette ashes were stuck to each other to determine whether they adhered to the polarizing plate sample according to the following evaluation.

A: No attachment even when taken up to 1 cm

AB: Attaches when taken from 1 to 4 cm

B: attached when brought to 4-10 cm

C: It adheres even more than 10 cm, If it is more than B, it is a level without technical problems.

The results shown in Table 2 show that when the conductive processed polyester film of the present invention is used as the separator film of the polarizing plate, the optical properties are excellent and dust adhesion can be prevented, so that the workability of failure detection in the product inspection is prevented. It shows excellent.

<Example 3>

[Production of separate film]

(Production of polyethylene terephthalate film No.1)

To 100 parts by weight of dimethyl terephthalate, 65 parts by weight of ethylene glycol, and 2 parts by weight of diethylene glycol, 0.05 parts by weight of magnesium acetate hydrate was added as a transesterification catalyst, and a transesterification reaction was carried out according to a conventional method. 0.05 weight part of antimony trioxide and 0.03 weight part of trimethyl phosphates were added to the obtained product. Subsequently, the mixture was gradually heated up and reduced in pressure to polymerize at 280 ° C and 0.5 mmHg to obtain polyethylene terephthalate having an intrinsic viscosity of 0.70, melting point (Tm) of 261 ° C, and glass transition temperature (Tg) of 76 ° C.

The polyethylene terephthalate was then vacuum dried at 150 ° C. for 8 hours, melt extruded at 285 ° C. using an extruder, adhered to the 30 ° C. cooling drum with electrostatic application, and cooled and solidified to obtain an unstretched sheet. This unstretched sheet was stretched 1.2 times in the longitudinal direction at 85 ° C. using a roll type drawing machine. The temperature difference between front and back was within 5 degreeC.

The obtained uniaxially stretched film was stretched 4.5 times in the transverse direction at 95 ° C using a tenter-type transverse stretching machine. It was then heat treated at 70 ° C. for 2 seconds and again heat set at 180 ° C. for 25 seconds in the heat fixation zone. Subsequently, it relaxed and wound up at 150 degreeC in the lateral (width) direction, and produced the biaxially-stretched polyethylene terephthalate (polyethylene terephthalate) film No. 1 of 1500 mm in width and 40 micrometers in thickness.

(Production of Polyethylene Terephthalate Film Nos. 2 to 16)

Polyethylene terephthalate films No. 2 to 16 were produced in the same manner except that the stretching ratios of longitudinal and lateral and heat setting temperatures were changed and produced as shown in Table 1 during film formation of polyethylene terephthalate film No. 1.

[Production of Polarizer and Protective Film]

A polyvinyl alcohol film having a thickness of 120 μm was immersed in an aqueous solution containing 1 part by weight of iodine, 2 parts by weight of potassium iodide, and 4 parts by weight of boric acid, and stretched 4 times at 50 ° C. to prepare a polarizing film.

Konica TAC film (Konica Tak KC80UVS) having a thickness of 80 µm was alkali treated with a 40 N 2.5 N sodium hydroxide aqueous solution for 60 seconds, washed again and dried to obtain a TAC film having an alkali treated surface.

On both sides of the polarizing film film, an alkali-treated surface of the TAC base was bonded on both sides using a 5% aqueous soap-type polyvinyl alcohol solution as an adhesive to prepare a polarizing plate.

[Production of Polarizing Plate Sample Nos. 1 to 16]

After performing light adhesion processing to one side of the polarizing plate produced above, the said polyethylene terephthalate film No. 1 was bonded as a separate film. After similarly performing adhesive processing on the opposite surface of a polarizing plate, the said polyethylene terephthalate film No. 1 was bonded as a separate film.

At this time, it bonded together so that the extending | stretching direction at the time of polarizing film preparation and the lateral stretching direction of a polyethylene terephthalate film may orthogonally cross. Similarly, polyethylene terephthalate film Nos. 2 to 16 were bonded together on both sides of the polarizing plate, and polarizing plate samples No. 1 to 16 were produced.

Evaluation was performed as described below about the polarizing plate samples No. 1-16 produced as mentioned above. The results are shown in Table 1.

(Assessment Methods)

〈Heat Shrinkage〉

150 mm x 150 mm samples are cut out with respect to polyethylene terephthalate films Nos. 1 to 16, and moisture is controlled for one day under conditions of 23 ° C. and 55% RH, followed by 100 mm intervals. Then, the heat treatment was performed at 80 ° C. for 30 minutes, and the gap interval after adjusting moisture for one day under 23 ° C. and 55% RH conditions was measured. The gap between the gaps before and after the heat treatment is determined and expressed as a percentage of the gap before the heat treatment. In addition, the direction contracted with respect to heat processing was +, and the direction extended | stretched was-.

<Orientation angle>

After film forming or slitting of polyethylene terephthalate films No. 16-16, it samples in the width direction 7 cm and the longitudinal direction 10 cm centering on the place which becomes 5 cm from the center part of a film, and a film edge part. The orientation angle | corner was measured using this "autobirefringence meter" (KOBURA-21DH type of Shin-Oji Paper Co., Ltd.). And the average value of the absolute value of the difference of the orientation angles of a center part and both ends was made into "the difference of orientation angles."

<Measurement of cross nicol concentration>

Two sheets of polarizing plate samples No. 1 to 16 were stacked so that the optical axis of the polarizing plate became orthogonal (cross nicol state), and the optical density was measured using a densitometer (DM500, manufactured by Dainippon Screen, Inc.).

The higher the optical density in the cross nicol state, the easier the spot failure at the time of inspecting the product of the polarizing plate is and the better the workability is. As optical density, 3.0 or more are preferable.

<Evaluation of interference nonuniformity>

The two sheets of polarizing plates samples No. 1 to 16 were stacked so that the optical axes of the polarizing plates became orthogonal (cross nicol state), placed on the observation table, and the interference nonuniformity seen on the polarizing plates was visually observed. The occurrence of interference non-uniformity interferes with the inspection of the foreign matter on the bright spot of the polarizing plate, and the less, the better the workability during product inspection.

A: The interference nonuniformity is not seen at all.

B: Slight interference interference is seen, but no problem

C: Difficult to work due to many interference unevenness

If it is B or higher, it is a problem without problem.

Planarity Assessment

Polarizing plate samples No. 1 to 16 were cut out at 60 cm x 100 cm (width direction x length direction), and placed on a die excellent in planarity to visually evaluate the bending of the base.

A: It is flat and sticks to the die.

B: Base shrinkage is seen everywhere.

C: The overall wave shape due to the contraction of the base.

As can be seen from Table 3, it was found that when the polyester film of the present invention was used as a separate film, the optical properties were excellent and the planarity was good even after the bonding of the polarizing plate. .

According to the present invention, the cost is low, the optical anisotropy, the interference nonuniformity, etc. are excellent, the optical characteristics are excellent, the workability of the defect detection of the polarizing plate is excellent, and the inspection can be performed in the bonded state, thus making it difficult to inspect the polarizing plate. Can be reduced. Furthermore, the separator film for polarizing plates and a polarizing plate unit can be provided.

Claims (29)

A polarizing film having a first side and a second side, A first protective film provided on the first surface of the polarizing film, A second protective film provided on the second surface of the polarizing film, A third protective film provided on the first protective film, and Separate film installed on the second protective film The polarizing plate unit which has a polarizing plate containing and the orientation angle of the said 3rd protective film or the said separate film is 80 degree or more. The polarizing plate unit according to claim 1, wherein the third protective film or the separate film is a resin film stretched 1.0 to 2.5 times in one direction and stretched 2.5 to 7.0 times in a direction orthogonal thereto. The polarizing plate unit according to claim 1, wherein the absolute value of the difference between the refractive index in the longitudinal direction of the third protective film and the separate film and the refractive index in the transverse direction is 0.02 or more. The polarizing plate unit according to claim 1, wherein a surface specific resistance at 23 ° C. and 25% RH of the third protective film or the separate film is 1 × 10 ¹² Ω /? Or less. The polarizing plate unit according to claim 2, wherein the third protective film or the separate film is a resin film heat-set in a temperature range of (Tm-150) to (Tm-25) ° C. The polarizing plate unit according to claim 1, wherein the third protective film or the separate film has a phase difference of 50 nm or more and a deviation of 50 nm or less. The polarizing plate unit of claim 1, wherein the third protective film or the separate film has a haze of 0.6% or less in an 80 μ conversion. The polarizing plate unit according to claim 1, wherein the third protective film or the separate film has a tear strength of 40 g or more in terms of 80 µ. The polarizing plate unit of claim 1, wherein the third protective film or the separate film has a tensile strength of 13 kg / mm 2 or more. The polarizing plate unit of claim 1, wherein the third protective film or the separate film has a coefficient of kinetic friction of 0.40 or less. The polarizing plate unit according to claim 1, wherein the third protective film or the separate film has a difference in the orientation angles of both ends and the center portion from 0 to 10 degrees. The polarizing plate unit according to claim 1, wherein the third protective film or the separate film has a heat shrinkage ratio of 80 ° C. for 30 minutes in both longitudinal and transverse directions. The polarizing plate unit according to claim 1, wherein the third protective film or the separate film is at least one selected from a polypropylene film, a polystyrene film, a polyethylene film, and a polyester film. The polarizing plate unit according to claim 2, wherein the third protective film or the separate film is at least one selected from a polypropylene film, a polystyrene film, a polyethylene film, and a polyester film. A polarizing film having a first side and a second side, A first protective film provided on the first surface of the polarizing film, A second protective film provided on the second surface of the polarizing film, A first separator film provided on the first protective film, and A second separate film provided on the second protective film The polarizing plate unit which has a polarizing plate containing and whose orientation angle of a said 1st separate film or a said 2nd separate film is 80 degrees or more. The polarizing plate unit according to claim 15, wherein the first separator film or the second separator film is stretched from 1.0 to 2.5 times in one direction and stretched 2.5 to 7.0 times in a direction orthogonal thereto. The polarizing plate unit according to claim 15, wherein the absolute value of the difference between the refractive index in the longitudinal direction and the cross-direction refractive index of the first or second separator film is 0.02 or more. The polarizing plate unit according to claim 15, wherein a surface specific resistance of 23 ° C. and 25% RH of the first or second separator film is 1 × 10 ¹² Ω /? Or less. The polarizing plate unit according to claim 15, wherein the first separator film or the second separator film is a resin film heat-set in a temperature range of (Tm-150) to (Tm-25) ° C. The polarizing plate unit according to claim 15, wherein the first separator film or the second separator film has a phase difference of 50 nm or more and a deviation of 50 nm or less. The polarizing plate unit according to claim 15, wherein the first separator film or the second separator film has a haze of 0.6% or less in a 80 μ conversion. The polarizing plate unit according to claim 15, wherein the first separator film or the second separator film has a tear strength of 40 g or more in terms of 80 µ. The polarizing plate unit of claim 15, wherein the first separator film or the second separator film has a tensile strength of 13 kg / mm 2 or more. The polarizing plate unit of claim 15, wherein the first separator film or the second separator film has a coefficient of kinetic friction of 0.40 or less. The polarizing plate unit of claim 15, wherein a difference between the alignment angles of both ends and the center portion of the first separator film or the second separator film is 0 to 10 degrees. The polarizing plate unit according to claim 15, wherein the first separator film or the second separator film has a heat shrinkage ratio of 80 ° C. for 30 minutes in both longitudinal and transverse directions. The polarizing plate unit of claim 15, wherein the first separator film or the second separator film is at least one selected from a polypropylene film, a polystyrene film, a polyethylene film, and a polyester film. The polarizing plate unit of claim 16, wherein the first separator film or the second separator film is at least one selected from a polypropylene film, a polystyrene film, a polyethylene film, and a polyester film. A liquid crystal cell having a first side and a second side, A first polarizing plate provided on the first surface of the liquid crystal cell, A second polarizing plate provided on a second surface of the liquid crystal cell, The first polarizer is on the outside compared to the second polarizer, The first polarizing plate includes a polarizing film having a first surface and a second surface, a first protective film provided on a first surface of the polarizing film, a second protective film provided on a second surface of the polarizing film, and the first protective film. A third protective film installed on the substrate, The third protective film has an orientation angle of 80 degrees or more.