KR20040075682A - Polarized film, polarized plate, oval shape polarized plate, and circle shape polarized plate - Google Patents

Abstract

PURPOSE: A polarizing film having improved durability, a polarizing plate, an elliptical polarizing plate, and a circular polarizing plate are provided to enhance the durability by using the polarizing film including a boron compound. CONSTITUTION: A polarizing film is formed with a polyvinyl alcohol film including a boron compound. The chemical shift is observed at -3ppm and -11ppm when the polarizing film is measured with the 11B-NMR by using a boron saturated aqueous solution as a standard material. When the peak intensity of the chemical shift -3ppm is divided by the peak intensity of the chemical shift -11ppm, the divided value is more than 4. The boron compound is formed with boric acid and the amount of the boric acid is 6g/m¬2 to 12g/m¬2.

Description

Polarizing film, polarizing plate, elliptical polarizing plate, and circular polarizing plate {POLARIZED FILM, POLARIZED PLATE, OVAL SHAPE POLARIZED PLATE, AND CIRCLE SHAPE POLARIZED PLATE}

TECHNICAL FIELD This invention relates to the polarizing film, polarizing plate, elliptical polarizing plate, and circular polarizing plate which are used suitably for a liquid crystal display device and are excellent in durability.

With the spread of liquid crystal display devices (hereinafter, LCDs), the demand for polarizers is rapidly increasing. In general, a polarizing plate has a protective film attached to both surfaces or one side of a polarizing layer having polarizing ability through an adhesive layer.

Polyvinyl alcohol (hereinafter referred to as PVA) is mainly used as a material of the polarizing layer, and the PVA film is uniaxially stretched, and then dyed with iodine or dichroic dye or dyed and stretched, and further polarized by crosslinking with a boron compound. A layered polarizing film is formed (see, for example, Japanese Unexamined Patent Publication No. 2002-86554).

Cellulostriacetate is mainly used as the protective film because it is optically transparent and has a small birefringence (see Japanese Laid-Open Patent Publication No. 2002-86554).

However, since PVA is hygroscopic, the polarizing film which consists of a PVA film is inferior in durability, and it is outstanding especially in a high temperature and high humidity environment.

Therefore, the objective of this invention is providing the polarizing film which consists of polyvinyl alcohol, and is excellent in durability, and the polarizing plate using this polarizing film.

1 is a schematic plan view illustrating an example of a method of obliquely stretching a PVA film.

2 is a schematic plan view showing an example of a method of obliquely stretching a PVA film.

3 is a schematic plan view showing an example of a method of diagonally stretching a PVA film.

4 is a schematic plan view showing an example of a method of diagonally stretching a PVA film.

5 is a schematic plan view illustrating an example of a method of diagonally stretching a PVA film.

6 is a schematic plan view illustrating an example of a method of obliquely stretching a PVA film.

7 is a schematic plan view showing a state of punching a conventional polarizing plate.

8 is a schematic plan view showing a state of punching out the polarizing plate of the present invention.

Fig. 9 is a schematic plan view showing the layer structure of the liquid crystal display in Example 2;

Fig. 10 is a schematic plan view showing the layer structure of the transflective liquid crystal display in Example 3;

Explanation of symbols on the main parts of the drawings

(A) Film introduction direction

(B) Film conveyance direction to the next step

(a) step of introducing the film

(b) drawing a film

(c) Process to send stretched film to next process

A1: The bite position to the support means of a film, and the starting point position of film stretch (real support starting point: right side)

B1: bite position to the support means of the film (left side)

C1: starting position of film stretching (substantial support starting point: left side)

Cx: film release position and the end point reference position of the film stretching (substantial support release point: left)

Ay: End point reference position of film extension (substantial support release point: right side)

| L1-L2 |: Stroke difference of left and right film support means

W: Actual width at the end of the stretching step of the film

θ: angle formed between the stretching direction and the film traveling direction

11, 21: center line of the introduction side film

12, 22: center line of film sent to next process

13, 23, 33, 43, 53, 63: the trajectory of the film support means (left side)

14, 24, 34, 44, 54, 64: the trajectory of the film support means (right side)

15, 25, 35, 45, 55, 65: introduction side film

16, 26, 36, 46, 56, 66: film sent to next process

17, 17 ', 27, 27': left and right film support start (bite) points

18, 18 ', 28, 28': Breakaway from left and right film support means

71, 81: absorption axis (stretch axis)

72, 82: longitudinal direction

91, 91 ', 101, 101': polarizing film

92: lower polarizer

93: upper polarizer

94, 94 ': optically anisotropic layer

95: anti-glare antireflection film

96, 106, 106 ': Shield (Fuji-taek)

97 and 107: liquid crystal cell

98, 108: Backlight

99: liquid crystal display device

102, 102 ': λ / 4 plate

103, 103 ': circular polarizer

99: transmissive liquid crystal display device

109: transflective liquid crystal display device

According to this invention, the polarizing film and polarizing plate of the following structure are provided, and the said objective of this invention is achieved.

1. In a polarizing film made of polyvinyl alcohol hardened with a boron compound, when the polarizing film is measured by ¹¹ B-NMR using a saturated aqueous solution of boric acid as a standard substance, chemical shifts are observed at -3 ppm and 11 ppm. And a value obtained by dividing the peak intensity of the chemical shift -3 ppm by the peak intensity of 11 ppm is 4 or more.

2. Said boron compound is boric acid, and boric acid content of polarizing film is 6 g / m <2> or more and less than 12 g / m <2>, The polarizing film of said 1 description characterized by the above-mentioned.

3. Polarizing plate with protective film on at least one side of polarizing film of said 1 or 2 base material.

4. An elliptical polarizing plate, characterized in that an optical compensation film formed of discotic liquid crystalline molecules is attached to the polarizing plates of the three substrates.

5. (a) The optical compensation film formed from liquid crystalline molecules is affixed to the polarizing plates of said 3 base material,

(b) this optical compensation film contains two layers of a 1st optically anisotropic layer and a 2nd optically anisotropic layer containing the horizontally aligned rod-like liquid crystalline compound,

(c) At least one of the rod-shaped liquid crystalline compounds contained in the first optically anisotropic layer and the second optically anisotropic layer is represented by general formula (I),

(d) the phase difference at a measurement wavelength of 550 nm of the first optically anisotropic layer is substantially?, the phase difference at a measurement wavelength of 550 nm of the second optically anisotropic layer is substantially? / 2, and

(e) The angle of the in-plane slow axis of a 2nd optically anisotropic layer and the in-plane slow axis of a 1st optically anisotropic layer is 60 +/- 5 degrees, The circular polarizing plate characterized by the above-mentioned.

General formula (I): Q1-L1-A1-L3-M-L4-A2-L2-Q2

In the general formula (I):

Q1 and Q2 each independently represent a polymerizable group.

L1, L2, L3 and L4 each independently represent a single bond or a divalent linking group, and at least one of L3 and L4 represents an -O-CO-O- group.

A1 and A2 represent a spacer group having 2 to 20 carbon atoms.

M represents a mesogenic group.

[Embodiment of the Invention]

The polarizing film of this invention consists of polyvinyl alcohol (PVA) hard-bonded (crosslinked) with a boron compound, Preferably boric acid. And when the said polarizing film was measured by ^11B -NMR (boron NMR) using saturated boric acid aqueous solution as a standard substance, chemical shift is observed in -3 ppm and 11 ppm, and peak intensity of -3 ppm of chemical shift is observed. The value divided by the peak intensity of 11 ppm is 4 or more, preferably 5 or more, more preferably 6 or more.

It is well known what crosslinking structure forms when PVA is bridge | crosslinked with a boron compound, and it is described, for example in "Application of a polarizing film" by Nagata Makoto Editing and CMC Publishing. The chemical shift of -3 ppm of the polarizing film is based on boron atoms in which the boron atoms form a crosslinking point by the hydroxyl group of PVA and the number of crosslinking points is 4 per boron atom. In addition, the chemical shift of 11 ppm is based on the boron atom whose number of crosslinking points is three per boron atom.

According to the findings of the present inventors, when the number of crosslinking points is 4 per boron atom, the number of crosslinking points is higher than the number of boron atoms having 3 crosslinking points per boron atom in the initial optical performance (especially contained in the polarizing film The orientation state of PVA) improves and it becomes the thing excellent in the durability of a polarizing film. In the present invention, the value obtained by dividing the peak intensity of the chemical shift -3 ppm by the peak intensity of 11 ppm is 4 or more, and the durability of the polarizing film is aimed at. In the present invention, this is defined as the four crosslinking ratio. The value obtained by dividing the peak intensity of the chemical shift -3 ppm by the peak intensity of the chemical shift of 11 ppm is preferably 5 or more, more preferably 6 or more.

The intensity ratio of the chemical shift can be made into the said range by raising a draw ratio by 4.5 to 5.5 times in 32-80 degreeC liquid temperature in the extending process for obtaining the polarizing film mentioned later, when the boron compound as a hard film to use is boric acid, for example. . At this time, the concentration of the boric acid in the polarizing film is preferably 6 g / m 2 or more and 12 g / m 2 or less. When a boron compound other than boric acid is used, a person skilled in the art can easily find out the appropriate range of the draw ratio and the concentration of the boron compound depending on the boron compound.

EMBODIMENT OF THE INVENTION Hereinafter, the polarizing film of this invention, the protective film which concerns on the polarizing plate of this invention, further a circular polarizing plate, an elliptical polarizing plate, etc. are demonstrated.

[Polarizing Film]

In this invention, although the thickness before extending | stretching of the PVA film used for a polarizing film is not specifically limited, From a stability of film support and the homogeneity of extending | stretching, 1 micrometer-1 mm are preferable and 20-200 micrometers is especially preferable. 2-100 micrometers is preferable and, as for the film thickness of the PVA film after extending | stretching, 10-25 micrometers is preferable for light leakage improvement.

Moreover, although the extending | stretching method of the polarizing film of this invention is not specifically limited, When extending | stretching with the "tilt stretching method" described in <stretching method> mentioned later, a long polarizing film in which an absorption axis is not parallel or perpendicular to the longitudinal direction can be obtained. desirable.

PVA saponifies polyvinyl acetate, and may contain components copolymerizable with vinyl acetate, such as unsaturated carboxylic acid, unsaturated sulfonic acid, olefins, and vinyl ethers, for example. Moreover, modified PVA containing an acetoacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group, etc. can also be used.

Although the saponification degree of PVA is not specifically limited, From a viewpoint of solubility, etc., 80-100 mol% is preferable and 90-100 mol% is especially preferable. Moreover, although the polymerization degree of PVA is not specifically limited, 1000-10000 are preferable and 1500-5000 are especially preferable.

<PVA dyeing prescription and method>

PVA is dyed with a polarizer to obtain a polarizing film. The dyeing step is performed by gas phase or liquid phase adsorption. When performing in a liquid phase and using iodine as a polarizer, dyeing is performed by immersing a PVA film in the iodine-potassium iodide aqueous solution. As for the mass ratio of 0.1-20 g / l of iodine, 1-200 g / l of potassium iodide, and potassium iodide, 1-200 are preferable. The dyeing time is preferably 10 to 5000 seconds, and the liquid temperature is preferably 5 to 60 ° C.

As a dyeing method, arbitrary means, such as application | coating or spraying of iodine or a dye solution, as well as dipping, are possible. The dyeing step may be placed before or after the stretching step described later, but is particularly preferably dyed in a liquid phase before the stretching step in that the film swells appropriately and the stretching becomes easy.

<Polarizers other than iodine>

It is also preferable to dye with a dichroic dye other than iodine. Specific examples of the dichroic dyes include dye compounds such as azo dyes, stilbene dyes, pyrazolone dyes, triphenylmethane dyes, quinoline dyes, oxazine dyes, thiazine dyes, and anthraquinone dyes. Can be mentioned. It is preferable to be water-soluble, but it is not limited to this. Moreover, it is preferable that hydrophilic substituents, such as a sulfonic acid group, an amino group, and a hydroxyl group, are introduce | transduced into these dichroic molecules. Specific examples of dichroic molecules include, for example, C. I. Direct. Yellow 12, C. I. Direct. Orange 39, C. I. Direct. Orange 72, C. I. Direct. Red 39, C. I. Direct. Red 79, C. I. Direct. Red 81, C. I. Direct. Red 83, C. I. Direct. Red 89, C. I. Direct. Viloet 48, C. I. Direct. Blue 67, C. I. Direct. Blue 90, C. I. Direct. Green 59, C. I. Acid. Red 37, etc., Japanese Unexamined Patent Publication No. 62-70802, Japanese Unexamined Patent Publication No. Hei 1-61202, Japanese Unexamined Patent Publication No. Hei 1-72907, Japanese Unexamined Patent Publication No. Hei 1-72907, The dye etc. which were respectively described in Unexamined-Japanese-Patent No. 1-183602, Unexamined-Japanese-Patent No. 1-248105, Unexamined-Japanese-Patent No. 1-265205, and Unexamined-Japanese-Patent No. 7-261024 are mentioned. These dichroic molecules are used as free acids or as salts of alkali metal salts, ammonium salts and amines. These dichroic molecules can produce polarizers having various colors by blending two or more kinds. It is preferable to mix | blend the compound (color) which has a black color, or mix | blend various dichroic molecules so that it may have black when a polarizing axis orthogonally crosses as a polarizing element or a polarizing plate because it is excellent in both single-sheet transmittance and polarization rate.

<Extension method>

Hereinafter, the method of diagonal stretch used preferably by this invention is demonstrated in detail. 1 and 2 show, in schematic plan view, a typical example of a method of diagonally stretching a PVA film. The diagonal stretching method is a step of introducing the raw film represented by (a) in the direction of arrow (a), the widthwise stretching step represented by (b), and the stretched film represented by (c) in the following steps, namely ( B) sending in the direction of the direction. Hereinafter, when referring to a "stretching process", the whole process for performing a diagonal stretch method including these (a)-(c) process is pointed out. The film is continuously introduced from the (a) direction and is initially supported at the point B1 by the support means on the left side as viewed from the upstream side. At this time, one film end is not supported at this time, and no tension is generated in the width direction. In short, the point B1 is not equivalent to the actual starting point of support of the present invention (hereinafter, referred to as "the actual starting point of support"). In the present invention, the actual support starting point is defined as the point where the film is supported at both ends. The actual support starting point is the support starting point A1 on the downstream side, and a straight line drawn approximately perpendicular to the center line 11 (FIG. 1) or the center line 21 (FIG. 2) of the introduction-side film from A1. 1) or two points of the point C1 intersecting the trajectory 23 (FIG. 2). Starting from this point, if the support means at both ends are conveyed at substantially constant speed, A1 is A2, A3... Move to An, and C1 is the same as C2, C3... Go to Cn. In other words, the straight line connecting the points An and Cn through which the support means, which is the reference point passes, becomes the stretching direction at that point.

In this stretching method, as An gradually lags behind Cn as in FIGS. 1 and 2, the stretching direction gradually inclines from the conveyance direction perpendicular. Substantial support release points (hereinafter referred to as "substantial support release points") are Cx points deviating from the support means upstream and the centerline 12 (FIG. 1) or centerline 22 of the film sent from Cx to the next process. A straight line drawn approximately perpendicular to FIG. 2) is defined as two points of point Ay at which the trajectory 14 (FIG. 1) or trajectory 24 (FIG. 2) of the opposite support means intersects. The angle in the direction of stretching of the final film is determined by the difference between the stroke Ay-Ax (i.e. | L1-L2 |) of the left and right support means at the end point (the actual support release point) of the actual stretching process and the distance W (Cx) of the actual support release point. And Ay's distance). Therefore, the inclination angle θ that the stretching direction makes with respect to the conveyance direction to the next step is an angle that satisfies tanθ = W / (Ay-Ax), that is, tanθ = W / | L1-L2 |. 1 and 2 is supported up to 18 (FIG. 1) or 28 (FIG. 2) even after the Ay point, but since the other end is not supported, no new widthwise stretching occurs, and 18 and 28 It is not the actual support release point of the present invention.

As described above, the actual support starting point at both ends of the film is not a simple biting point to each of the left and right supporting means. The two actual support starting points are more strictly described above, and the straight line connecting one of the left and right support points with the other support point is approximately orthogonal to the center point of the film introduced in the process of supporting the film, and these two support points are also It is defined as located most upstream. Equally, the two actual support release points are those at which the straight line connecting one of the left and right support points and the other support point is approximately orthogonal to the center line of the film which is sent to the next process, and these two points are also defined as located most downstream. Here, substantially orthogonal means that the straight line which connects the center line of a film, right and left real support starting point, or a real support release point is 90 +/- 0.5 degrees.

In order to have a left and right stroke difference using a tenter type stretching machine, due to mechanical constraints such as rail length, a large deviation often occurs between the bite point to the support means and the actual support start point, or the deviation from the support means. There are cases where a large deviation occurs between the point and the actual support releasing point. When the process between the actual support starting point and the actual support releasing point defined above satisfies the relationship of the following formula (1), oblique stretching is achieved.

Equation (1): | L2-L1 |> 0.4W

In the above, the inclination angle of the orientation axis in the obtained stretched film can be controlled and adjusted at the ratio of the exit width W of the step (c) and the stroke difference | L1-L2 | of the two left and right substantially supporting means. In polarizing plates and retardation films, films which are often 45 ° aligned in the longitudinal direction are required. In this case, in order to obtain an orientation angle close to 45 °, it is preferable to satisfy the following formula (2),

Equation (2): 0.9 W <| L1-L2 | <1.1 W

More preferably, it is preferable to satisfy the following formula (3).

Formula (3): 0.97 W <| L1-L2 | <1.03 W

The structure of a specific extending process is shown by the specific example illustrated in FIGS. 1-6 which obliquely stretches a polymer film by satisfying Formula (1), These can be arbitrarily designed in consideration of installation cost and productivity.

The angle formed by the film introduction direction (a) to the stretching step and the film conveyance direction (b) to the next step can be any number, but from the viewpoint of minimizing the total design area of the facility including the step before and after stretching, It is preferable that the angle is smaller, preferably within 3 °, and more preferably within 0.5 °. For example, this value can be achieved in the structure as illustrated in FIGS. 1 and 4. Thus, in the method in which the film advancing direction does not substantially change, it is difficult to obtain the orientation angle of 45 degrees with respect to the longitudinal direction preferable as a polarizing plate and a retardation film only by enlarging the width | variety of a support means. Therefore, | L1-L2 | can be enlarged by providing the process of extending | stretching once and shrinking like FIG. In this invention, when using a diagonal stretch method, 1.1-10.0 times are preferable, and, as for a draw ratio, 2-10 times are more preferable, Especially preferably, it is 4.5-5.5 times. The shrinkage rate after that is preferably 10% or more. Moreover, as shown in FIG. 4, it is also preferable to repeat | stretch plural-times contraction several times, because | L1-L2 | can be enlarged.

In addition, from the viewpoint of minimizing the equipment cost of the stretching step, the smaller the number of times of bending and the angle of bending of the path of the support means, the better. From this point of view, as shown in Figs. 2, 3 and 5, the film advancing direction so that the angle between the advancing direction of the film at the exit of the step of supporting the both ends of the film and the actual drawing direction of the film is inclined 20 to 70 °. It is preferable to bend in the state which supported both ends of a film.

As a device which extends a film by providing tension while supporting both ends, what is called a tenter device like FIGS. 1-5 is preferable. In addition to the conventional two-dimensional tenter, as shown in FIG. 6, a stretching step of allowing the gripping means at both ends to have a stroke difference in a spiral shape may be used.

In the case of a tenter type drawing machine, there are many structures in which a chain in which a clip is fixed travels along a rail, and this uneven stretching method is adopted as a result, as illustrated in FIGS. 1 and 2. There is a case that the end is shifted and left and right at the same time so as not to be separated. In this case, the actual process lengths L1 and L2 are not merely the distance between the bite-off as described above, but the stroke lengths of the portions where both ends of the film are supported by the support means as described above.

If there is a difference in advancing speed on the right and left sides of the film at the exit of the stretching step, wrinkles and blurring occur at the exit of the stretching step, so that the conveyance speed differences of the left and right film holding means are required to be substantially the same speed. The speed difference is preferably 1% or less, more preferably less than 0.5%, most preferably less than 0.05%. The speed described here refers to the length of the trajectory of each of the left and right supporting means per minute. In general tenter stretching machines, there are speed unevennesses which are generated by orders of seconds or less, and often several% of unevenness, depending on the period of the sprocket driving the chain, the frequency of the driving motor, and the like. It does not correspond to the speed difference described in the invention.

In addition, as the left and right stroke difference occurs, wrinkles and blurring occur in the film. In order to solve this problem, the supportability of a PVA film is maintained, a volatile fraction exists in the state which extends 5% or more, and after extending | stretching, a volatile fraction is reduced, shrinking. Here, "maintaining the supportability of a PVA film" means that the film can be supported on both sides without impairing the film property. In addition, "stretching with a state where the volatility fraction is 5% or more exists" does not necessarily mean maintaining the state where the volatility fraction is 5% or more through the whole process of the stretching process. As long as the effect is expressed, it means that a part of the process may have a portion having a volatile content of 5% or less. The method of containing volatile matter in this form includes casting a film, containing volatile matter such as water or non-aqueous solvent, immersing, applying and spraying volatile matter such as water or non-aqueous solvent before stretching, and water or non-aqueous solvent during stretching. The method of apply | coating the volatile matter of this etc. is mentioned. Since hydrophilic polymer films, such as polyvinyl alcohol, contain water in a high temperature, high humidity atmosphere, it can contain volatile matter by extending | stretching after humidity control in high humidity atmosphere, or extending | stretching under high humidity conditions. In addition to these methods, any means may be used as long as the volatile content of the film can be 5% or more.

The maximum volatile fraction is possible as long as the supportability of the film is maintained. In polyvinyl alcohol, the volatile fraction is preferably 10% to 100%.

In addition, you may perform shrinkage | contraction of the stretched PVA film in any process at the time of extending | stretching and after extending | stretching. As a means for shrinking a film, a method of removing volatile matter by heating may be used. However, any means may be used as long as the film is shrunk. The volatilization amount after drying is preferably 3% or less, more preferably 2% or less, and even more preferably 1.5% or less.

Thus, (i) at least 1.1 to 20.0 times in the film width direction, (ii) the longitudinal traveling speed difference of the supporting device at both ends of the film is 1% or less, and (iii) at the exit of the step of supporting both ends of the film. The film advancing direction was bent while supporting both ends of the film such that the angle formed between the advancing direction of the film and the substantially extending direction of the film was inclined 20 to 70 °, and (iv) the supportability of the polymer film was maintained, and the volatile fraction was The extending | stretching method which consists of reducing the volatile fraction while shrink | contracting after extending | stretching while extending | stretching with a state which is 5% or more is a preferable aspect of the diagonal stretch method.

Rails regulating the trajectory of the support means often require large bending rates. For the purpose of avoiding interference between the film holding means or sudden stress concentration by the sudden bending, it is preferable that the trajectory of the holding means draws an arc at the bent portion.

Although the thickness of the film before extending | stretching is not specifically limited, From a viewpoint of the stability of film support and the homogeneity of extending | stretching, 1 micrometer-1 mm are preferable, and 20-200 micrometers is especially preferable.

The stretched film of PVA obtained in this way is dyed from the characteristic in which the orientation axis | shaft is inclined with respect to the longitudinal direction, and is used suitably as a polarizing film. In particular, a polarizing film whose inclination angle (azimuth angle) of the absorption axis (orientation axis) is 45 ± 5 ° with respect to the longitudinal direction is preferably used as a polarizing plate for LCD. More preferred azimuth is 45 ± 1 °.

〈Coverage (bridge)〉

In this invention, in the process of extending | stretching a PVA film and manufacturing a polarizing film, the film hardening agent containing a boron compound is added to a PVA film, and it dries (crosslinks).

As the boron compound, those described in US Reissue Patent No. 232897, specifically, boric acid and borax can be preferably used, but boric acid can be most preferably used. Moreover, metal salts, such as zinc, cobalt, zirconium, iron, nickel, and manganese, can also be added to a film film.

The means for containing the film-forming agent in the PVA film is not particularly limited, and any method such as dipping, applying, or spraying the film into the liquid can be used, and in particular, the dipping method and the coating method are preferable. As the coating means, any conventionally known means such as a roll coater, a die coater, a bar coater, a slide coater, a curtain coater and the like can be selected. Moreover, the method of contacting a film with cloth, cotton, a porous raw material, etc. which contained the solution are also preferable.

The timing for imparting the film-forming agent is not particularly limited, and may be performed before stretching, or after stretching, or until the end of the step (b) of the example in FIGS. 1 and 2 in which the widthwise stretching is substantially terminated. It is preferable to perform in a process. Most of the dura mater by crosslinking advances between the drying process immediately after application of this dura mater.

Moreover, you may provide the washing | cleaning and washing process after adding a hardening agent.

It is most preferable to perform the process of providing a film to a PVA film by the immersion process using a boric acid containing aqueous solution to the boron compound as a film.

In that case, it is preferable to contain 1 mass% or more and 3 mass% or less of potassium iodide in this boric acid containing aqueous solution. When the potassium iodide content in the boric acid-containing aqueous solution is less than 1% by mass, the light transmittance in the short wavelength region of the polarizing plate increases, but the amount of polyiodine ions generated decreases, and the absorption of the long wave side decreases and yellows. This becomes difficult. When the potassium iodide content exceeds 3 mass%, the light transmittance in the short wavelength region of a polarizing plate will fall.

In addition, the amount of boric acid in boric-acid containing aqueous solution is not specifically limited. For example, it is about 2-15 mass parts of boric acid with respect to 100 mass parts of water, Preferably it is about 4-10 mass parts with respect to 100 mass parts of water.

Moreover, as conditions for immersion treatment, the immersion treatment temperature in boric acid containing aqueous solution becomes like this. Preferably it is 32 degreeC-80 degreeC, More preferably, it is 35 degreeC-72 degreeC. The treatment time is preferably 60 seconds to 1200 seconds.

Moreover, when boric acid is used as a boron compound, it is preferable to make content of boric acid in a polarizing film 6 g / m <2> or more and 12 g / m <2> or less, More preferably, it is 6.5 g / m <2> or more and 9 g / m <2> or less.

In addition, in this invention, when the polarizing film of this invention is measured by ^11B -NMR by adjusting the addition amount to the PVA film of a film film, and the draw ratio in the said diagonal stretch process, chemical shift is -3 ppm and 11 ppm. It is observed and controlled so that the value obtained by dividing the peak intensity of the chemical shift -3 ppm by the peak intensity of the chemical shift of 11 ppm is 4 or more, preferably 5 or more, more preferably 6 or more. That is, the draw ratio and the concentration of the boron compound are controlled so that the number of boron atoms when the number of crosslinking points is 4 per boron atom is satisfied so that the number of crosslinking points satisfies the above strength ratio than the number of boron atoms having 3 boron atoms per atom. do.

[Shield]

The polarizing film is used as a polarizing plate by attaching a protective film to both surfaces or one side through an adhesive layer or an adhesive layer. The kind of protective film is not specifically limited, Cellulose acylates, such as cellulose acetate and cellulose acetate butyrate, polycarbonate, a polyolefin, polystyrene, polyester, etc. can be used. Physical properties such as transparency, proper moisture permeability, low birefringence, and proper rigidity are required for the protective film of the polarizing plate. Overall, cellulose acylates are preferable, and cellulose acetate is particularly preferable.

Although the physical property of a protective film can be arbitrary value according to a use, the typical preferable value at the time of using for a normal reflective LCD is shown below. As for a film thickness, 5-500 micrometers is preferable from a viewpoint of handleability and durability, 20-200 micrometers is more preferable, 20-100 micrometers is especially preferable. 30-85 micrometers is preferable for the purpose of light leakage improvement. As for retardation value, 0-150 nm is preferable in 632.8 nm, 0-20 nm is more preferable, 0-5 nm is especially preferable.

In the present invention, in order to improve the light transmittance in the short wave region, the absorption axis of the polarizing film has an azimuth angle of preferably 45 ± 5 ° and more preferably 45 ± 3 ° with respect to the slow axis of the protective film. The absorption axis of a polarizing plate and the slow axis of a protective film can take arbitrary angles in each case, such as having a function which changes a polarizing property to a protective film.

The visible light transmittance of the protective film is preferably at least 60%, particularly preferably at least 90%. It is preferable that it is 0.3 to 0.01%, and, as for the dimension reduction after 90 degreeC 120-hour process, it is especially preferable that it is 0.15 to 0.01%. 50-1000 Mpa is preferable and, as for the tensile strength value by the tension test of a film, 100-300 Mpa is especially preferable. As for the water vapor transmission rate, 100-1000 g / m <2> * day is preferable, and 300-900 g / m <2> * day is especially preferable.

Of course, the application to the present invention is not limited to the above values.

The detail of the cellulose acylate which is preferable as a protective film is shown below. Preferable cellulose acylate is that degree of substitution of cellulose with a hydroxyl group satisfies all of the following formulas (I) to (IV).

(I): 2.6 ≤ A '+ B' ≤ 3.0

(II): 2.0 ≤ A '≤ 3.0

(III): 0 ≤ B '≤ 0.8

(IV): 1.9 <A'- B '

Here, A and B represent the substituent of the acyl group substituted by the hydroxyl group of cellulose, A 'is a substitution degree of an acetyl group, and B' is a substitution degree of the acyl group of 3-5 carbon atoms. In cellulose, there are three hydroxyl groups in one glucose unit, and the said number shows substitution degree with respect to three hydroxyl groups, and maximum substitution degree is 3.0. In general, cellulose triacetate is a case where A's substitution degree A 'is 2.6 or more and 3.0 or less (in this case, the maximum number of unsubstituted hydroxyl groups is 0.4), and B' = 0 is the cellulostriacetate. The cellulose acylate used as the polarizing plate protective film is preferably a cellulose group acetate in which all of the acyl groups are acetyl groups, and an acetyl group of 2.0 or more, an acyl group having 3 to 5 carbon atoms of 0.8 or less and an unsubstituted hydroxyl group of 0.4 or less. In the case of an acyl group having 3 to 5 carbon atoms, 0.3 or less is particularly preferable in view of physical properties. In addition, substitution degree is obtained by calculation by measuring the binding degree of acetic acid substituted by the hydroxyl group of cellulose, and a C3-C5 fatty acid. As a measuring method, it can carry out based on ASTMD-817-91.

Other acyl groups of 3 to 5 carbon atoms of the acetyl group are propionyl group (C ₂ H ₅ CO-), butyryl group (C ₃ H ₇ CO-) (n-, iso-), valeryl group (C ₄ H ₉ CO -) (n-, iso-, sec-, tert-), of which n-substituted ones are preferred in terms of mechanical strength and ease of dissolution, and particularly n-propionyl groups. Moreover, when the substitution degree of an acetyl group is low, mechanical strength and heat-and-moisture resistance will fall. When the degree of substitution of the acyl group having 3 to 5 carbon atoms is high, the solubility in an organic solvent is improved. However, when each degree of substitution is the above range, good physical properties are shown.

As for the polymerization degree (viscosity average) of cellulose acylate, 200-700 are preferable and 250-550 are especially preferable. A viscosity average polymerization degree can be measured with an Ostwald viscometer and is calculated | required by the following formula from the intrinsic viscosity [(eta)] of the measured cellulose acylate.

DP = [η] / Km (where DP is viscosity average degree of polymerization and Km is an integer 6 × 10 ^-4 )

As the cellulose of the cellulose acylate raw material, there are cotton linter, wood pulp, and the like. The cellulose acylate obtained from any raw cellulose may be used, or may be mixed and used.

The cellulose acylate is usually produced by the sorbent cast method. The sorbent cast method dissolves cellulose acylate and various additives in a solvent to prepare a concentrated solution (hereinafter referred to as dope), which is cast on an endless support such as a drum or a band, and the solvent is evaporated to form a film. . It is preferable that dope adjusts concentration so that solid content may be 10-40 mass%. It is preferable to finish the surface of a drum or a band in a mirror state. For the casting and drying method in the sorbent cast method, U.S. Pat.Nos. 2,336,310, 2,367,603, 2,492,078, 2,492,977, 2,492,978, 2,607,704, 2,739,069, 2,739,070, and British Patent 640731, Each specification of Unexamined-Japanese-Patent No. 736892, Unexamined-Japanese-Patent No. 45-4554, 49-5614, Unexamined-Japanese-Patent No. 60-176834, 60-203430, 62-115035 is described.

A method of casting two or more layers of dope is also preferably used. In the case of casting a plurality of dope, a film may be produced while flexibly laminating and laminating a solution containing the dope from a plurality of oil studies formed at intervals in the advancing direction of the support, for example. The method described in Japanese Patent Laid-Open No. 61-158414, Japanese Unexamined Patent Publication No. Hei 1-22419, Japanese Patent Application Laid-Open No. Hei 11-198285, and the like can be applied. Moreover, you may make it film by casting a cellulose acylate solution from two oil studies, For example, Unexamined-Japanese-Patent No. 60-27562, Unexamined-Japanese-Patent No. 61-94724, Unexamined-Japanese-Patent No. 61-947245, Japan It can implement by the method of Unexamined-Japanese-Patent No. 61-104813, Unexamined-Japanese-Patent No. 61-158413, and Unexamined-Japanese-Patent No. 6-134933. Moreover, the casting method of wrapping the flow of the high viscosity dope of Unexamined-Japanese-Patent No. 56-162617 with the low viscosity dope, and simultaneously extruding the high viscosity and the low viscosity dope can also be used preferably.

Examples of organic solvents that dissolve cellulose acylate include hydrocarbons (eg benzene, toluene), halogenated hydrocarbons (eg methylene chloride, chlorobenzene), alcohols (eg methanol, ethanol, diethylene glycol), ketones (eg acetone) ), Esters (e.g. ethyl acetate, propyl acetate), ethers (e.g. tetrahydrofuran, methylcellosolve) and the like. Hydrogen halides having 1 to 7 carbon atoms are preferably used, and methylene chloride is most preferably used. From the viewpoints of physical properties such as solubility of cellulose acylate, peelability from the support, mechanical strength of the film, and the like, it is preferable to mix one or several alcohols having 1 to 5 carbon atoms in addition to methylene chloride. 2-25 mass% is preferable with respect to the whole solvent, and, as for content of alcohol, 5-20 mass% is more preferable. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, and the like, and methanol, ethanol, n-butanol, or a mixture thereof is preferably used.

In addition to cellulose acylate, components that become solid after drying include plasticizers, heat stabilizers such as ultraviolet absorbers, inorganic fine particles, salts of alkaline earth metals such as calcium and magnesium, antistatic agents, flame retardants, lubricants, emulsions, and peelings from supports. It may optionally contain an accelerator, a hydrolysis inhibitor of cellulose acylate, and the like.

Phosphoric acid ester or carboxylic acid ester is used as a plasticizer added preferably. Examples of the phosphate ester include triphenyl phosphate (TPP) and tricresyl phosphate (TCP), cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like. Phthalic acid ester and citric acid ester are typical as carboxylic acid ester. Examples of phthalate esters include dimethylphthalate (DMP), diethylphthalate (DEP), dibutylphthalate (DBP), dioctylphthalate (DOP), diphenylphthalate (DPP) and diethylhexylphthalate (DEHP). Examples of citrate esters include O-acetyl triethyl citrate (OACTE) and O-acetyl citrate tributyl (OACTB), acetyl triethyl citrate, and acetyl tributyl citrate.

Examples of other carboxylic acid esters include trimellitic acid esters such as butyl oleate, methylacetyl ricinoleate, dibutyl sebacate and trimethyl trimellitate. Examples of glycolic acid esters include triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, and the like.

Among the plasticizers exemplified above, triphenyl phosphate, biphenyl diphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diethylhexyl phthalate and tria It is preferable to use cetine, ethyl phthalyl ethyl glycolate, trimethyl trimellitate and the like. Especially triphenyl phosphate, biphenyl diphenyl phosphate, diethyl phthalate, ethyl phthalyl ethyl glycolate, and trimethyl trimellitate are preferable. These plasticizers may be one type, or may use 2 or more types together. 5-30 mass% is preferable with respect to cellulose acylate, and, as for the addition amount of a plasticizer, 8-16 mass% or less is especially preferable. These compounds may be added together with cellulose acylate and a solvent at the time of preparation of a cellulose acylate solution, and may be added in solution preparation or after preparation.

According to the objective, a ultraviolet absorber can select arbitrary types, and can use absorbers, such as a salicylic acid ester type, a benzophenone type, a benzotriazole type, a benzoate type, a cyanoacrylate type, and a nickel complex salt type, and can use a benzophenone type. , Benzotriazole type and salicylic acid ester type are preferable. Examples of benzophenone ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-acetoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2'-di-hydride Hydroxy-4-methoxybenzophenone, 2,2'-di-hydroxy-4,4'-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4- Dodecyloxy benzophenone, 2-hydroxy-4- (2-hydroxy-3- methacryloxy) propoxy benzophenone, etc. are mentioned. As the benzotriazole ultraviolet absorber, 2 (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorbenzotriazole and 2 (2'-hydroxy-5'-tert-butylphenyl ) Benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) benzotriazole, 2 (2'-hydroxy-3', 5'-di-tert-butylphenyl ) -5-chlorbenzotriazole, 2 (2'-hydroxy-5'-tert-octylphenyl) benzotriazole, etc. are mentioned. Examples of the salicylic acid ester include phenyl salicylate, p-octylphenyl salicylate, p-tert-butylphenyl salicylate, and the like. Among these exemplified ultraviolet absorbers, 2-hydroxy-4-methoxybenzophenone, 2,2'-di-hydroxy-4,4'-methoxybenzophenone and 2 (2'-hydroxy-3'- tert-butyl-5'-methylphenyl) -5-chlorbenzotriazole, 2 (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5' Particular preference is given to -di-tert-amylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorbenzotriazole.

It is particularly preferable to use a plurality of absorbents having different absorption wavelengths in combination so that a high blocking effect can be obtained in a wide wavelength range. 0.01-5 mass% is preferable with respect to cellulose acylate, and, as for the quantity of a ultraviolet absorber, 0.1-3 mass% is especially preferable. A ultraviolet absorber may be simultaneously added at the time of cellulose acylate melt | dissolution, and may be added to the dope after melt | dissolution. In particular, the form which adds a ultraviolet absorber solution to dope just before casting using a static mixer etc. is preferable.

As the inorganic fine particles to be added to the cellulose acylate, silica, kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide, alumina and the like can be optionally used according to the purpose. It is preferable to disperse | distribute these microparticles | fine-particles in a binder solution by arbitrary means, such as a high speed mixer, a ball mill, an atomizer, an ultrasonic disperser, before adding to dope. As the binder, cellulose acylate is preferable. It is also preferable to disperse | distribute with other additives, such as a ultraviolet absorber. Although a dispersion solvent is arbitrary, it is preferable that it is a composition close to a dope solvent. 0.01-100 micrometers is preferable and, as for the number average particle diameter of a dispersed particle, 0.1-10 micrometers is especially preferable. The dispersion may be added at the same time to the cellulose acylate dissolving step or may be added to the dope in any step. However, a form in which the dispersion is added immediately before casting using a static mixer like an ultraviolet absorber is preferable.

As a peeling accelerator from a support body, surfactant is effective and it does not specifically limit, such as a phosphoric acid type, a sulfonic acid type, a carboxylic acid type, a nonionic type, and a cationic type. These are described, for example, in Japanese Patent Laid-Open No. 61-243837.

When using the said cellulose acylate film for a protective film, as a means of providing hydrophilicity in order to improve adhesiveness with PVA system resin, a flame treatment and a glow discharge treatment are mentioned to a film surface besides a corona treatment. Moreover, you may disperse | distribute hydrophilic resin in the solvent which has affinity with cellulose acylate, and may apply | coat thin layer.

On the protective film surface of the polarizing plate of this invention, the optically anisotropic layer for viewing angle compensation of LCD as described in Unexamined-Japanese-Patent No. 4-229828, Unexamined-Japanese-Patent No. 6-75115, 8-50206, etc., Anti-glare layer or anti-reflection layer for improving the visibility of display, or layer having PS wave separation function by anisotropic scattering or anisotropic optical interference for improving LCD brightness (polymer dispersed liquid crystal layer, cholesteric liquid crystal layer, etc.) Arbitrary functions such as a hard coat layer for improving the scratch resistance of the polarizing plate, a gas barrier layer for suppressing the diffusion of moisture and oxygen, a polarizing film or an adhesive, an easy-adhesive layer for improving adhesion to the pressure-sensitive adhesive, and a layer for providing slipperiness. A layer can be formed.

A functional layer may be formed in the polarizing film side, may be formed in the surface opposite to a polarizing film, and can be suitably selected according to the objective.

[Circular Polarizer, Elliptical Polarizer]

Retardation film is affixed to the polarizing plate of this invention through an adhesion layer and an adhesive layer, and it can be set as a circular polarizing plate or an elliptical polarizing plate.

When the linearly polarized light is incident on the circularly polarizing plate, at 400 to 700 nm of the measurement wavelength, almost complete circularly polarized light is applied at any wavelength; on the contrary, when the totally circularly polarized light is incident on the laminated retardation film, the wavelength is 400 to 700 nm. In almost any wavelength, almost complete linearly polarized light can be obtained.

The circularly polarizing plate is formed such that the angle between the λ / 4 plate or λ / 2 plate and the polarizing plate and the slow axis in the plane of these λ / 4 plate or λ / 2 plate and the absorption axis (polarization axis) of the polarizing plate is substantially 45 °. It is obtained by attaching. Substantially 45 degrees means the range of 40 degrees-50 degrees, Preferably it is 43 degrees-47 degrees, More preferably, it is the range of 44 degrees-46 degrees.

The elliptical polarizing plate is formed of a λ / 4 plate and a λ / 2 plate and the polarizing plate, and the angle between the slow axis in the plane of the λ / 4 plate and the λ / 2 plate and the absorption axis (polarization axis) of the polarizing film is substantially 75 ° or 15 degrees. It can also be obtained by adhering so that it becomes °. Substantially 75 degrees means the range of 70 degrees-80 degrees, Preferably it is 73 degrees-78 degrees, More preferably, it is the range of 74 degrees-76 degrees. Substantially 15 degrees means the range of 11 degrees-19 degrees, Preferably it is 13 degrees-17 degrees, More preferably, it is the range of 14 degrees-16 degrees.

In addition, an elliptical polarizing plate and a circular polarizing plate can also be obtained by adhering the optical compensation film formed of liquid crystalline molecules to the polarizing plate. Hereinafter, the elliptical polarizing plate and circular polarizing plate with an optical compensation film are demonstrated. In addition, elliptically polarizing plate and circularly polarizing plate are referred to below simply as this type of polarizing plate, respectively.

(Ellipse polarizer)

The elliptical polarizing plate of the present invention is formed by attaching an optical compensation film formed of discotic liquid crystalline molecules to the polarizing plate. As a preferable embodiment of an optical compensation film, what laminated | stacked the optically anisotropic layer formed from the orientation layer and the discotic liquid crystalline molecule on the transparent base film is mentioned.

An example in which an alignment layer, an optically anisotropic layer, and the polarizing film and the protective film (the polarizing plate is composed of the polarizing film and the protective film) are laminated in this order on a transparent base film as a preferable example of the configuration of the elliptical polarizing plate of this type. It may include, but is not limited to. In the above example, the angle between the absorption axis of the polarizing film and the slow axis of the optically anisotropic layer is preferably substantially parallel.

<Liquid crystalline compound>

It is preferable that the optical compensation film which comprises the elliptically polarizing plate of this invention has an optically anisotropic layer which consists of a liquid crystalline compound. In addition, a discotic compound (discotic liquid crystal) is preferably used for this liquid crystalline compound.

Examples of discotic liquid crystals include C. Destrade et al., Mol. Cryst. 71, page 111 (1981), Benzene Derivatives, C. Destrade et al., Mol. Cryst. Torkisen derivatives described in Vol. 122, page 141 (1985), Physics lett, A, Vol. 78, page 82 (1990), B. Kohne et al., Angew, Chem. The cyclohexane derivatives described in Volume 96, page 70 (1984) and J. M. Lehn et al., J. Chem. Commun., Page 1794 (1985), by J. Zhang et al., J. Am. Chem. Soc. Azacrown-type, phenylacetylene-type macrocycle etc. which are described in volume 116, page 2655 (1994) are mentioned.

Discotic liquid crystals generally have a molecular nucleus as a nucleus, and have a structure in which a linear alkyl group, an alkoxy group, a substituted benzoyloxy group, or the like is radially substituted as the linear chain, and shows liquid crystallinity. However, as long as the molecule itself has negative uniaxiality and can provide a constant orientation, it is not limited to the above description.

In addition, in the optically anisotropic layer which comprises the polarizing plate of this invention, the "liquid crystalline compound" of the optically anisotropic layer which consists of a liquid crystalline compound does not need to be liquid crystalline, for example, the group which the said low molecular weight discotic liquid crystal reacts with heat, light, etc. As a result, they may be polymerized or crosslinked by a reaction by heat, light, or the like, and may be high molecular weight to lose liquid crystallinity to form an optically anisotropic layer.

Preferable examples of the discotic liquid crystal are described in Japanese Patent Laid-Open No. Hei 8-50206.

The optically anisotropic layer constituting the elliptically polarizing plate of the present invention is preferably a layer having a negative birefringence consisting of a compound having a discotic structure, and the surface of the discotic structure is inclined with respect to the transparent substrate, and the discotic It is preferable that the angle which the surface of a structure and the transparent base material surface make changes to the depth direction of an optically anisotropic layer.

The angle (inclined angle) of the face of the discotic structure is generally increasing or decreasing in the depth direction of the optically anisotropic layer and with increasing distance from the bottom of the optically anisotropic layer. The inclination angle preferably increases with increasing distance. Further, the change in the inclination angle includes a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, and an intermittent change including an increase and a decrease. The intermittent change includes a region in which the inclination angle does not change in the thickness direction. It is preferable that the inclination angle is increased or decreased as a whole even if it includes the region which does not change. In addition, the inclination angle is preferably increased as a whole, and particularly preferably continuously changed.

The optically anisotropic layer is generally applied by applying a solution in which a discotic compound and other compounds are dissolved in a solvent onto an alignment film, followed by drying to a discotic nematic phase formation temperature, and then maintaining an orientation state (discotic nematic phase). It is obtained by cooling. Alternatively, the optically anisotropic layer is applied by applying a solution in which a discotic compound and other compounds (such as a polymerizable monomer and a photopolymerization initiator) are dissolved in a solvent, onto an alignment film, followed by drying to a discotic nematic phase forming temperature followed by polymerization (UV By irradiation with light or the like). As a discotic nematic liquid crystal phase-solid-state transition temperature of the discotic liquid crystalline compound used for this invention, 70-300 degreeC is preferable, and 70-170 degreeC is especially preferable.

The inclination angle of the discotic structure on the transparent base film side of the optically anisotropic layer can generally be adjusted by selecting the material of the discotic compound or the alignment film, or by selecting the rubbing treatment method. Incidentally, the inclination angle of the discotic structure on the reflective surface side (air side) can generally be adjusted by selecting a discotic compound or other compounds (eg, plasticizers, surfactants, polymerizable monomers and polymers) used with the discotic compound. . The degree of change of the inclination angle can also be adjusted by the above selection.

As the plasticizer, the surfactant, and the polymerizable monomer, any compound may be used as long as it has compatibility with the discotic compound and can change the inclination angle of the liquid crystalline discotic compound or does not inhibit the orientation. Among these, polymerizable monomers (eg, compounds having a vinyl group, vinyloxy group, acryloyl group, and methacryloyl group) are preferable. The compound is generally used in an amount of 1 to 50% by mass, preferably 5 to 30% by mass relative to the discotic compound.

As the polymer used together with the discotic compound, any polymer can be used as long as it has compatibility with the discotic compound and can change the tilt angle of the liquid crystalline discotic compound. Examples of the polymer include cellulose esters. Preferred examples of the cellulose esters include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose and cellulose acetate butyrate. The polymer is generally in an amount of 0.1 to 10% by mass (preferably 0.1 to 8% by mass, particularly preferably 0.1 to 5% by mass) with respect to the discotic compound so as not to inhibit the orientation of the liquid crystalline discotic compound. Is used.

A preferred embodiment of the optically anisotropic layer composed of a discotic liquid crystalline compound is composed of a cellulose acetate film as a transparent base film, an alignment film formed thereon, and a layer composed of a discotic liquid crystal formed on the alignment film, and an alignment film is a crosslinked polymer. It is an optically anisotropic layer which is a rubbing process film | membrane formed.

<Alignment Film>

Preferable examples of the alignment film used in the present invention include the alignment film described in JP-A-9-152509. Moreover, the orientation film used for the circularly polarizing plate mentioned later is also used preferably.

<Transparent base film>

As a cellulose acetate film as said transparent base film, the cellulose acetate film for protective films mentioned above in detail can be used. Moreover, the transparent base film used for the circularly polarizing plate mentioned later can also be used. Especially, the cellulose acetate whose acelation degree is 59.0-61.5% is preferable. As for thickness, 20-200 micrometers is preferable.

<Use of elliptical polarizing plate>

The elliptical polarizing plate of the present invention described above has a function of optically compensating the viewing angle characteristic of liquid crystal cell birefringence, and is preferably used for expanding the viewing angle of a TFT liquid crystal display device.

(Circular polarizer)

Circular polarizer of the present invention,

(a) an optical compensation film formed of liquid crystalline molecules is attached to the polarizing plate,

(b) this optical compensation film contains two layers of a 1st optically anisotropic layer and a 2nd optically anisotropic layer containing the horizontally aligned rod-like liquid crystalline compound,

(c) At least one of the rod-shaped liquid crystalline compounds contained in the first optically anisotropic layer and the second optically anisotropic layer is represented by the following general formula (I),

(d) the phase difference at the measurement wavelength of 550 nm of the first optically anisotropic layer is substantially?, the phase difference at the measurement wavelength of 550 nm of the second optically anisotropic layer is substantially? / 2, and

(e) The angle between the in-plane slow axis of the second optically anisotropic layer and the in-plane slow axis of the first optically anisotropic layer is 60 ± 5 °.

Moreover, the angle which the absorption axis of a polarizing film and the longitudinal direction of a transparent base film make is 45 degrees, and the rod-shaped liquid crystalline compound is oriented horizontally, respectively. The long axis direction of the rod-like liquid crystal compound corresponds to the slow axis in the plane of the optically anisotropic layers (first and second).

General formula (I): Q1-L1-A1-L3-M-L4-A2-L2-Q2

In the above general formula (I):

Q1 and Q2 each independently represent a polymerizable group.

L1, L2, L3 and L4 each independently represent a single bond or a divalent linking group, and at least one of L3 and L4 represents a -O-CO-O- group.

A1 and A2 represent spacer groups having 2 to 20 carbon atoms.

M represents a mesogenic group.

<Optical anisotropic layer composed of rod-like liquid crystal compound>

In the circular polarizing plate of the present invention, the rod-like liquid crystal compound of the general formula (I) is used as a rod-like liquid crystal compound oriented in at least one of the first optically anisotropic layer and the second optically anisotropic layer.

Hereinafter, a polymeric rod-like liquid crystal compound is demonstrated.

In general formula (I), Q1 and Q2 are each independently a polymeric group. The polymerization reaction of the polymerizable group is preferably addition polymerization (including ring-opening polymerization) or condensation polymerization. That is, it is preferable that a polymeric group is a functional group in which addition polymerization reaction or condensation polymerization reaction is possible. Hereinafter, the example of a polymeric group is shown.

Divalent linking groups represented by L1, L2, L3 and L4 include -O-, -S-. -CO-, -NR ^2- , -CO-O-, -O-CO-O-, -CO-NR ^2- , -NR ² -CO-, -O-CO-, -O-CO-NR ² It is preferably a divalent linking group or a single bond selected from the group consisting of-, -NR ² -CO-O-, -NR ² -CO-NR ^2- . R ² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom. In this case, at least one of L3 or L4 is -O-CO-O- (carbonate group).

Among the groups represented by the combination of Q1 and L1 or Q2 and L2, CH ₂ = CH-CO-O-, CH ₂ = C (CH ₃ ) -CO-O-, and CH ₂ = C (Cl) -CO- O- is preferred, and most preferably CH ₂ = CH-CO-O-.

A1 and A2 represent a spacer group having 2 to 20 carbon atoms, and an aliphatic group having 2 to 12 carbon atoms is preferable. The spacer group is more preferably in the form of a chain, and may contain oxygen atoms or sulfur atoms which are not adjacent to each other. Moreover, a halogen atom (fluorine, chlorine, bromine), a cyano group, a methyl group, and an ethyl group may be substituted as a substituent.

As the mesogenic group represented by M, all known mesogenic groups can be used. In particular, group represented by the following general formula (II) is preferable.

General formula (II):-(-W1-L5) n-W2-

Here, W1 and W2 represent a divalent cyclic aliphatic group, a divalent aromatic group, a divalent heterocyclic group, L5 represents a group represented by L1 to L4, and -CH ₂ -O-, -O-CH _2-. , n represents 1, 2 or 3; W1 and W2 include 1,4-cyclohexanediyl, 1,4-phenylene, pyrimidine-2,5-diyl, pyridine-2,5-diyl, 1,3,4-thiadiazole-2,5- Diyl, 1,3,4-oxadiazole-2,5-diyl, naphthalene-2,6-diyl, naphthalene-1,5-diyl, thiophene-2,5-diyl, pyridazine-3,6- Dile is mentioned. In the case of 1,4-cyclohexanediyl, there are structural isomers of the trans and cis, and in the present invention, any isomer may be used or a mixture of any ratio may be used. It is more preferable that it is a trans body. W1 and W2 may have a substituent, and examples of the substituent include a halogen atom (fluorine, chlorine, bromine and iodine), a cyano group, an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, etc.), and 1 to 10 carbon atoms. Alkoxy groups (methoxy groups, ethoxy groups, etc.), acyl groups having 1 to 10 carbon atoms (formyl group, acetyl group, etc.), alkoxycarbonyl groups having 1 to 10 carbon atoms (methoxycarbonyl group, ethoxycarbonyl group, etc.), carbon atoms The acyloxy group (acetyloxy group, propionyloxy group etc.) of 1-10, a nitro group, a trifluoromethyl group, a difluoromethyl group, etc. are mentioned. Preferable examples of the basic skeleton of the mesogenic group represented by General Formula (II) are as follows. These substituents may be substituted by these.

Although the specific example of a compound represented by general formula (I) of this invention below is shown, this invention is not limited to these. In addition, the compound represented by general formula (I) can be synthesize | combined by the method of Unexamined-Japanese-Patent No. 11-513019.

In the optically anisotropic layer, the rod-shaped liquid crystalline compound is preferably oriented substantially uniformly, more preferably fixed in a substantially uniform oriented state, and the liquid crystalline compound is fixed by a polymerization reaction. Most preferably. It is preferable to make the rod-shaped liquid crystalline compound of this invention into homogeneous orientation.

In the circular polarizing plate of the present invention, a rod-like liquid crystalline compound represented by General Formula (I) and another rod-like liquid crystalline compound may be used in combination. Other rod-shaped liquid crystalline compounds include azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, and cyano substitutions. Phenylpyrimidines, alkoxy substituted phenylpyrimidines, phenyldioxanes, transs and alkenylcyclohexylbenzonitriles are preferably used.

Not only the low molecular liquid crystalline molecules described above, but also the high molecular liquid crystalline molecules can be used. It is more preferable to fix the orientation of the rod-like liquid crystalline molecules by polymerization, and as the polymerizable rod-like liquid crystalline molecules, Makromol. Chem., 190, 2255 pages (1989), 5 Advanced Materials, 107 pages (1993), US Patents 4,683,327, 5,622,648, 5,770,107, World Patent (WO) 95/22586, 95 / 24455, 97/00600, 98/23580, 98/52905, JP 1-272551, 6-16616, 7-110469, 11-80081, And the compounds described in Japanese Patent Application No. 2001-64627.

In order to form the two-layer optically anisotropic layer containing the above liquid crystal compound on the said polarizing plate, the orientation film mentioned later, a 1st optically anisotropic layer, and a 2nd optically anisotropic layer are laminated on this transparent base film in this order, and (lambda) / 4 After forming a plate, it can carry out by attaching this (lambda) / 4 plate to the single side | surface of the polarizing film which consists of said PVA.

<Formation of the first and second optically anisotropic layers>

The two-layer optically anisotropic layer is first coated with a coating liquid for a first optically anisotropic layer containing a rod-like liquid crystalline compound and the following polymerization initiator or other additives on the alignment film on the transparent base film, and then the first optically anisotropic layer. It can form by apply | coating the coating liquid for 2nd optically anisotropic layers which has the same composition on it.

At this time, the angle between the in-plane slow axis of the first optically anisotropic layer and the longitudinal direction of the transparent base film is such that the left side 30 ° ± 5 ° or the right side 30 ° ± 5 ° and the in-plane slow axis of the second optically anisotropic layer. It is preferable to orient the rod-like liquid crystal compound contained in the optically anisotropic layer so that the angle of the in-plane slow axis of the first optically anisotropic layer is left 60 ° ± 5 ° or right 60 ° ± 5 °. In addition, a well-known method can be used as a method of making the in-plane slow axis of a 1st optically anisotropic layer and the in-plane slow axis of a 2nd optically anisotropic layer into such a relationship, but the surface of a 1st optically anisotropic layer is rubbed, The coating liquid for 2nd optically anisotropic layers can be apply | coated on it, and a 2nd optically anisotropic layer can be formed.

As a solvent used for preparation of the coating liquid for optically anisotropic layers, an organic solvent is used preferably. Examples of organic solvents include amides (eg N, N-dimethylformamide), sulfoxides (eg dimethylsulfoxide), heterocyclic compounds (eg pyridine), hydrocarbons (eg benzene, hexane), alkyl halides (eg , Chloroform, dichloromethane), esters (eg methyl acetate, butyl acetate), ketones (eg acetone, methyl ethyl ketone), ethers (eg tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. You may use together 2 or more types of organic solvents. Application of the coating liquid can be carried out by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

It is preferable to maintain the orientation state and to fix the oriented liquid crystalline compound. It is preferable to perform fixation by the polymerization reaction of the polymeric group introduce | transduced into a liquid crystalline compound. Although the polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator, a photopolymerization reaction is more preferable. Examples of photopolymerization initiators include α-carbonyl compounds (described in the specifications of US Pat. Nos. 2,367,661 and 2,367,670), acyloinethers (described in the specification of US Pat. Nos. 2,448,828), α-hydrocarbon substituted aromatic acyl compounds (US Pat. No. 2,722,512). ), Polynuclear quinone compounds (described in the specifications of US Pat. No. 3,046,127, US Pat. No. 2,951,758), combinations of triarylimidazole dimers and p-aminophenylketones (described in US Pat. No. 3,549,367), acridine and phena Gin compounds (Japanese Laid-Open Patent Publication No. 60-105667, described in US Pat. No. 4,239,850) and oxadiazole compounds (described in US Pat. No. 4,212,970).

It is preferable that it is 0.01-20 mass% of solid content of a coating liquid, and, as for the usage amount of a photoinitiator, it is more preferable that it is 0.5-5 mass%. It is preferable to use ultraviolet-ray for the light irradiation for superposition | polymerization of a liquid crystalline compound. The irradiation energy is preferably 20 mJ / cm 2 to 50 mJ / cm 2, more preferably 100 to 800 mJ / cm 2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. It is preferable that it is 0.1-10 micrometers, and, as for the thickness of an optically anisotropic layer, it is more preferable that it is 0.5-5 micrometers.

<Additive for orientation control on the air interface side>

In the homogeneous orientation (horizontal orientation) of a polymeric rod-shaped liquid crystal compound, it is horizontal at the orientation film side, but is inclined (tilt) orientation at the air interface side. In order to suppress this phenomenon, it is preferable to use an additive, and it is especially preferable to use the additive represented by following formula (V-1) (V-3).

<Alignment Film>

In order to orient the rod-shaped liquid crystal compound, it is preferable to use an alignment film. The alignment film is an organic compound (e.g., ω) by rubbing treatment of an organic compound (preferably a polymer), evaporation of an inorganic compound, formation of a layer having microgroups, or by a Langer-Belget method (LB film). -Trichoic acid, dioctadecyldimethylammonium chloride, methyl stearyl acid, etc.), and the like. Moreover, the orientation film which an orientation function produces by provision of an electric field, provision of a magnetic field, or light irradiation is also known. The alignment film formed by the rubbing process of a polymer is especially preferable. The rubbing treatment is performed by rubbing the surface of the polymer layer several times in a predetermined direction using paper or cloth.

The kind of polymer used for an oriented film is determined according to the orientation (especially average inclination angle) of a liquid crystalline compound.

In order to orientate a liquid crystal compound horizontally, the polymer (normally an alignment polymer) which does not reduce the surface energy of an oriented film is used. About the kind of specific polymer, it mentions in various literature about a liquid crystal cell or an optical compensation sheet.

In any alignment film, it is preferable to have a polymerizable group for the purpose of improving the adhesiveness of a liquid crystal compound and a transparent support body. A polymerizable group can introduce the repeating unit which has a polymeric group in a side chain, or can introduce as a substituent of a cyclic group. It is more preferable to use the alignment film which forms a chemical bond with a liquid crystalline compound at an interface, and it is described in Unexamined-Japanese-Patent No. 9-152509 as such an alignment film.

It is preferable that it is 0.01-5 micrometers, and, as for the thickness of an oriented film, it is more preferable that it is 0.05-1 micrometer.

In addition, after aligning the rod-like liquid crystal compound using the alignment film, the rod-like liquid crystal compound is fixed in the alignment state to form an optical anisotropic layer, and only the optical anisotropic layer may be transferred onto the polarizing film (or transparent support). .

The rod-like liquid crystal compound in which the alignment state is fixed can maintain the alignment state even without the alignment film. Therefore, in the circular polarizing plate of the present invention, the alignment film is not essential (although essential in the production of the λ / 4 plate).

<Transparent base film>

It is preferable to use a polymer film with a small wavelength dispersion as a transparent base film. It is also preferable that a transparent base film is small in optical anisotropy. Transparent substrate means that the light transmittance is 80% or more. It is preferable that ratio of Re400 / Re700 is less than 1.2 specifically that wavelength dispersion is small. Specifically, it is preferable that in-plane retardation (Re) is 20 nm or less, and, as for an optical anisotropy is small, it is more preferable that it is 10 nm or less. It is preferable that the elongate transparent base film has a roll shape, and after laminating | stacking an optically anisotropic layer using a roll-shaped transparent base film, it cut | disconnects to a required size. Examples of polymers include cellulose esters, polycarbonates, polysulfones, polyethersulfones, polyacrylates and polymethacrylates. Cellulose esters are preferred, acetyl cellulose is more preferred, and triacetyl cellulose is most preferred. It is preferable to form a polymer film by the sorbent cast method. It is preferable that it is 20-50 micrometers, and, as for the thickness of a transparent base film, it is more preferable that it is 50-200 micrometers.

In order to improve the adhesion of the transparent substrate film and the layer (adhesive layer, vertical alignment film or optically anisotropic layer) formed thereon, the transparent substrate film is subjected to surface treatment (e.g., glow discharge treatment, colonna discharge treatment, ultraviolet (UV) treatment, Flame treatment). You may form an adhesion layer (undercoat layer) on a transparent base film.

<Use of circularly polarizing plate>

The circularly polarizing plate of the present invention described above has the characteristic of making non-polarized light circularly polarized, and is preferably used for a reflective liquid crystal display device, a transflective liquid crystal display device, or the like.

EXAMPLE

Example 1

<Production of Polarizing Plate A>

After immersing and washing both sides of a PVA film having an average degree of polymerization of 2400 and a film thickness of 75 μm in ion-exchanged water, the PVA film was immersed in an aqueous solution of 1.0 g / L of iodine and 120.0 g / L of potassium iodide at 25 ° C. for 60 seconds. It was. Further, after immersion in an aqueous solution of 75 g / L boric acid and 30 g / L of potassium iodide at 45 ° C. for 90 seconds, excess water was removed from both sides of the film, and introduced into a tenter stretching machine of the form shown in FIG. 1.

The conveyance speed was sent out at 4 m / min using a tenter drawing machine, and after extending | stretching to 5.0 times in the temperature of 60 degreeC humidity 98% atmosphere, the width was kept constant and it dried at 70 degreeC for 4 minutes.

Subsequently, a protective film (a saponification-treated Fuji Photo Film Co., Ltd.) Fuji-Tak (cellulose cellulose acetate, retardation value 3.0 nm) was made by using a 4% aqueous solution of PVA (PVA-124H) by Kuraray Co., Ltd. as an adhesive agent on both surfaces of a PVA film. Film thickness: 80 µm)) was further heated at 70 ° C. for 30 minutes. Then, it separated from the tenter and cut | disconnected the edge with 3 cm and a cutter from the width direction, and produced the polarizing plate A of the roll form of effective width 500mm and length 50m.

In the obtained polarizing plate, the absorption axis direction of the polarizing film was inclined 45 ° with respect to the slow axis of the protective film.

(Measurement of Single Plate Transmittance and Polarization Degree)

The polarizing plate A was sample-cut at 2x5 cm, and the transmittance | permeability was measured with Shimadzu magnetic spectrophotometer UV3100. The polarization degree P (%) was calculated | required by following Formula, making the transmittance | permeability in case of overlapping by overlapping the two absorption plates of polarizing plates as H0 (%), and making the transmittance | permeability in case of overlapping by orthogonal absorption axis.

P = [(H0-H1) / (H0 + H1)] ^1/2 × 100

In addition, single-sheet transmittance | permeability was calculated | required by correcting visibility of the transmittance | permeability of 400-700 nm using one sample.

The single plate transmittance of the polarizing plate A was 43.2%, and the polarization degree was 99.97%.

(Measurement of Boric Acid Content)

The protective film of polarizing plate A was peeled off, the liquid extracted with the ascorbic acid aqueous solution (0.1 mass%) was diluted (20 times), and it measured by ICP-AES. Boric acid content of the polarizing plate A was 8.6 g / m <2>.

(Measurement of 4 Crosslinking Point Ratio by ¹¹ B-NMR Measurement)

The protective film was removed on both sides (chloroform swelled), cut into rectangular shapes and mounted on a 7 mm diameter rotor. ¹¹ B-NMR measurement (MAS method, rotation 3000 Hz, pulse 1.0 microsec) was performed using Brucker solid NMR (300 MHz). It was 7.2 when the ratio of 4 bridge | crosslinking points of boric acid was computed from ratio (① / 2) of peak intensity (1) of chemical shift -3 ppm and peak intensity (2) of 11 ppm of obtained NMR spectrum.

<Production of Comparative Polarizing Plate B>

After immersing and washing both sides of a PVA film having an average degree of polymerization of 2400 and a film thickness of 75 μm in ion-exchanged water, the PVA film was immersed in an aqueous solution of 1.0 g / L of iodine and 120.0 g / L of potassium iodide at 25 ° C. for 60 seconds. It was. Further, after immersion in an aqueous solution of 42 g / L boric acid and 30 g / L of potassium iodide at 25 ° C. for 90 seconds, excess water was removed from both sides of the film, and introduced into the tenter stretching machine in the form of FIG. 1.

The conveying speed was sent out at 4 m / min using a tenter drawing machine, and after extending | stretching to 4.0 times in the temperature of 60 degreeC humidity 98% atmosphere, the width was kept constant and it dried at 70 degreeC for 4 minutes.

Subsequently, a protective film (a saponification-treated Fuji Photo Film Co., Ltd.) Fuji-Tak (cellulose cellulose acetate, retardation value 3.0 nm) was made by using a 4% aqueous solution of PVA (PVA-124H) by Kuraray Co., Ltd. as an adhesive agent on both surfaces of a PVA film. Film thickness: 80 µm)) was further heated at 70 ° C. for 30 minutes. Then, it separated from the tenter and cut | disconnected the edge with 3 cm and the cutter from the width direction, and produced the comparative polarizing plate B of the roll form of 500 mm of effective width and length 50m.

The single plate transmittance of the comparative polarizing plate B was 42.2%, and the degree of polarization was 99.92%. In addition, the boric acid content of the comparative polarizing plate B was 5.2 g / m <2>, and the 4 bridge | crosslinking point ratio of boric acid was 3.8.

(Endurance test)

The polarizing plate A and the comparative polarizing plate B mentioned above were put into the following two types of constant temperature and humidity tanks, the durability test was done, and the single-plate transmittance and polarization degree after a test were measured.

(1) wet durability: 80 ℃ 90% RH environment, left for 24 hours

(2) dry durability: 100 ℃ dry environment, left for 24 hours

The results are shown in Table 1.

Wet durability (90% at 80 ℃ 24 hours) Single Plate Transmittance T (%) Polarization degree P (%) Before the test After the test ΔT Before the test After the test ΔP Polarizing film A 43.20 43.90 0.70 99.97 99.85 -0.12 Comparative Polarizing Film B 42.20 44.98 2.78 99.92 97.10 -2.82

Dry durability (100 ℃ dry 24 hours)

Single Plate Transmittance T (%) Polarization degree P (%) Before the test After the test ΔT Before the test After the test ΔP Polarizing film A 43.20 43.37 0.17 99.97 99.87 -0.10 Comparative Polarizing Film B 42.20 43.59 1.39 99.92 99.41 -0.51

Example 2

<Production of Optical Compensation Film A>

To 30 g of linear alkyl-modified PVA (MP-203, manufactured by Kuraray Co., Ltd.), 130 g of water and 40 g of methanol were added, stirred, and dissolved, followed by filtration with a polypropylene-made filter having a pore diameter of 30 µm and a coating liquid for an alignment layer. Was prepared.

On the other hand, a triacetyl cellulose film (manufactured by Fuji Photo Film Co., Ltd.), which is a support having a thickness of 100 μm having an undercoat layer of a gelatinous thin film (0.1 μm), was prepared, and the coating liquid for alignment layer was applied on the support using a bar coater. Applied. After application | coating, after drying at 60 degreeC, the rubbing process was performed to the 45 degree direction with respect to MD direction, and the orientation layer of thickness 0.5micrometer was formed.

Next, 1.6 g of compound LC-1 having the following structure as a liquid crystalline discotic compound, 0.4 g of phenoxydiethylene glycol acrylate (M-101, manufactured by Toagose Co., Ltd.), cellulose acetate butyrate (CAB531-1, Eastman Chemical) Co., Ltd.) 0.05 g and 0.01 g of a photopolymerization initiator (Irgacure-907, manufactured by Chiba Co., Ltd.) were dissolved in 3.65 g of methyl ethyl ketone, followed by filtration with a polypropylene-made filter having a pore diameter of 1 μm. Was prepared.

On the alignment layer, the coating liquid for optical anisotropic layer was applied using a bar coater, and dried at 120 ° C. Then, it heated at 120 degreeC again for 3 minutes, aged liquid crystal, and orientated the discotic compound. In addition, ultraviolet rays were irradiated at 120 ° C. using an air-cooled metal halide lamp of 160 W (manufactured by IGraphics Co., Ltd.) so as to have an irradiation intensity of 400 mW / cm 2 and an amount of irradiation energy of 300 mJ / cm 2 to cure the coating layer, and the thickness was 1.8. The optical compensation film A was produced by forming the optically anisotropic layer of micrometers.

<Production of Elliptical Polarizing Plate A>

In <Manufacture of Polarizing Plate A> of Example 1 mentioned above, after extending | stretching and drying at 70 degreeC for 4 minutes after extending | stretching, the process of sticking a protective film using PVA as an adhesive agent on both surfaces of a PVA film was replaced by the following process. That is, after extending | stretching for 4 minutes at 70 degreeC after extending | stretching, the protective film (Fujitak, Cellulose Street manufactured by Fuji Photo Film Co., Ltd.) which saponified one side using PVA (PVA-124A mentioned above) as an adhesive agent on both surfaces of a PVA film | membrane. Acetate, retardation value 3.0 nm, film thickness 80 micrometers) was affixed using the optical compensation film A which saponified the other surface, and heated at 70 degreeC for 30 minutes. At this time, the support surface on the opposite side to the side on which the optically anisotropic layer was formed was attached to the polarizing film so that the rubbing direction of the alignment layer of the optical compensation film A coincided with the stretching direction of the polarizing film.

Then, it separated from the tenter and cut | disconnected the edge with 3 cm and a cutter from the width direction, and produced the elliptical polarizing plate A of roll shape of 500 mm of effective width and length 50m.

The absorption axis direction of the obtained elliptical polarizing plate was inclined at 45 ° with respect to the longitudinal direction.

<Production of Comparative Elliptical Polarizing Plate B>

The comparative elliptically polarizing plate B was produced similarly to the elliptically polarizing plate A by combining the polarizing plate B for a comparative example, and the optical compensation film A.

<Production of transmissive liquid crystal display device>

Elliptical polarizing plates A 'and B' were produced in the above-mentioned elliptical polarizing plates A and B using commercially available anti-glare antireflection film (Sanritsu Co., Ltd. product) instead of Fuji Photo Film Co., Ltd. product Fujitag.

As shown in FIG. 9, the elliptical polarizing plate A is made into the lower polarizing plate 92 of the backlight 98 side in the two polarizing plates 92 and 93 which sandwich the liquid crystal cell 97 of the transmissive liquid crystal display device 99. , The elliptically polarizing plate A 'was used as the upper polarizing plate 93 to attach the surface side of the optically anisotropic layers 94 and 94' of the viewing angle compensation film to the liquid crystal cell 97 through an adhesive, thereby producing a transmissive liquid crystal display device I. . In addition, the thing for 20 inches was used for the liquid crystal cell.

As a comparative example, a transmissive liquid crystal display device II was fabricated in the same manner as the liquid crystal display device I using the elliptical polarizing plate B as the lower polarizing plate 92 and the elliptical polarizing plate B 'as the upper polarizing plate 93.

About the liquid crystal display device produced above, the light leakage of the liquid crystal display device was evaluated by the following method. The results are shown in Table 2.

(Light Leakage Evaluation of Liquid Crystal Display)

After using the produced liquid crystal display device at 40 degreeC and 30% RH for 1 month, the backlight of the liquid crystal display device was lighted and the light leak was visually observed by making the whole surface into black display one hour later. It was evaluated in four steps as follows.

◎: no light leakage

○: slight light leakage at the edge of the quadrilateral

△: sure light leakage at edge

X: There is light leakage to around film center

Light leakage rating Liquid Crystal Display I ◎ LCD Display II ×

From the results shown in Table 2, it was found that the liquid crystal display device I using the elliptic polarizing plate using the polarizing plate of the present invention has less light leakage than the liquid crystal display device II using the comparative elliptic polarizing plate.

Example 3

<Production of λ / 4 edition>

(Formation of the first optically anisotropic layer)

An optically isotropic triacetylcellulose film (degree of acemination 60.9%) having a thickness of 80 µm, a width of 680 mm, and a length of 500 m was used as the transparent support. After saponifying both surfaces of this transparent support body, the alignment film application liquid of the following composition was apply | coated continuously to the single side | surface of the transparent support body, and it dried, and the alignment film of 1 micrometer in thickness was formed. Next, the rubbing process was performed on the alignment film continuously in the left 30 ° direction with respect to the longitudinal direction of the transparent support.

(Orientation film coating liquid composition)

10 mass% of the following modified polyvinyl alcohols

371 mass% of water

119% by mass methanol

Glutalaldehyde 0.5 mass%

On the alignment layer, the coating liquid for the first optically anisotropic layer having the following composition was continuously applied, dried, and heated (oriented aging) using a bar coater, and further irradiated with ultraviolet light to form a first optically anisotropic layer having a thickness of 2.0 μm. . The first optically anisotropic layer had a slow axis in the direction of 30 ° with respect to the longitudinal direction of the transparent support. In addition, the retardation (Re550) in 550 nm of the 1st optically anisotropic layer was 265 nm (Moreover, retardation was measured using Oji Measurement Co., Ltd. product KOBRA21DH).

(Coating Liquid Composition for First Optically Anisotropic Layer)

Rod-shaped liquid crystalline compound (example compound I-2) 38.1 mass%

0.38 mass% of the following sensitizers

1.14 mass% of following photoinitiators

0.38 mass% of the following additives

Glutalaldehyde 0.04 mass%

Methyl ethyl ketone 60.0 mass%

(Formation of Second Optically Anisotropic Layer)

The rubbing process was performed on the 1st optically anisotropic layer continuously so that it might become 60 degrees to the right with respect to the slow axis of the 1st optically anisotropic layer produced above.

On the first optically anisotropic layer subjected to the rubbing treatment, the coating liquid for the second optically anisotropic layer having the following composition was continuously applied, dried, and heated (orientation aged) using a bar coater. Furthermore, ultraviolet irradiation was carried out to form a second optically anisotropic layer having a thickness of 1.0 μm, thereby producing a phase difference plate (λ / 4 plate A).

(Coating Liquid Composition for Second Optically Anisotropic Layer)

Rod-shaped liquid crystalline compound (example compound I-2) 38.4 mass%

0.38 mass% of sensitizer used for the coating liquid for 1st optically anisotropic layers

1.15 mass% of photoinitiators used for the coating liquid for 1st optically anisotropic layers

0.06 mass% of Exemplary Compound (V-1)

Methyl ethyl ketone 60.0 mass%

The retardation (in-plane phase difference) of (lambda) / 4 plate A of this invention was 144 nm in 111 nm, measurement wavelength 550 nm, 135 nm, and measurement wavelength 630 nm in 450 nm of measurement wavelengths.

<Production of Circular Polarizer A>

In the polarizing plate A of Example 1 mentioned above, after extending | stretching and drying at 70 degreeC for 4 minutes, the process of sticking a protective film using PVA as an adhesive agent on both surfaces of a PVA film was substituted as follows. In other words, λ / 4 obtained by saponification of Fuji Photo Film Co., Ltd. manufactured by Fuji Photo Film Co., Ltd. (cellulose cellulose acetate, retardation value of 3.0 nm, film thickness of 80 µm) and the other side of the PVA film. Plate A was affixed and heated again at 70 degreeC for 30 minutes. At this time, the support surface on the opposite side to the side where the 1st optically anisotropic layer and the 2nd optically anisotropic layer of (lambda) / 4 plate A are formed was made to adhere to a polarizing film. Then, it separated from the tenter and cut | disconnected the edge with 3 cm and a cutter from the width direction, and produced the circularly polarizing plate A of the roll form of 500 mm of effective width and length 50m.

<Production of Circular Polarizer B>

According to Example 3 of WO 00/26705, a polycarbonate copolymer stretched film (λ / 4 plate B) was produced.

The in-plane phase difference was 162.9 nm in 148.5 nm and wavelength 650 nm at 148.5 nm, wavelength 550 nm, and wavelength 450 nm.

In addition, K value was defined by the following equation.

K = (n _z- (n _x + n _y ) / 2) × d

In the above formula, n _x and n _z are three-dimensional refractive indices of the film, and the refractive indices of the x-axis, y-axis, and z-axis directions are respectively, and d is the thickness of the film. The K value at the wavelength of 450 nm was -73.8, the K value at the wavelength of 550 nm was -80.5, and the K value at the wavelength of 650 nm was -81.5.

(Formation of Adhesive Layer)

18 parts by mass of an isocyanate-based curing agent solution (Toyo Morton, Inc. "trade name; CAT-561") was added to 100 parts by mass of a polyester resin solution (Toyo Morton Corporation "brand name; TM-593"), followed by ethyl acetate. It diluted so that solid content concentration might be 20 mass%, and the polyurethane adhesive solution A was obtained. This adhesive solution A was apply | coated with the bar coater on the surface of the said (lambda) / 4 plate B which carried out the colonnade discharge treatment.

(Production of Circularly Polarizing Plate B Integrated with λ / 4 Plate B)

In the polarizing plate A of Example 1 mentioned above, after extending | stretching at 70 degreeC after extending | stretching for 4 minutes, the process of sticking a protective film using PVA as an adhesive agent on both surfaces of a PVA film was replaced as follows. That is, λ / in which an adhesive bond layer was formed on the other side of the PVA film, the Fuji Photo Film Co., Ltd. manufacture Fuji Taek (Cellulostriacetate, retardation value 3.0 nm, film thickness of 80 µm) and the other side of the PVA film were saponified. Four plates B were attached and heated at 70 ° C. for 30 minutes. At this time, the adhesive bond layer of (lambda) / 4 plate B was made to adhere to a polarizing film. Then, it separated from the tenter and cut | disconnected the edge with 3 cm and the cutter from the width direction, and produced the circularly polarizing plate B of the roll form of 500 mm of effective width and length 50m.

<Production of Comparative Polarizing Plates C and D>

In the combination of polarizing plate B and (lambda) / 4 plate A, the comparative circular polarizing plate C was produced similarly to the circular polarizing plate A, and was produced. In addition, in the combination of polarizing plate B and (lambda) / 4 plate B, the comparative circular polarizing plate D was produced similarly to the circular polarizing plate B, and was produced.

<Production of Semi-Transmissive Liquid Crystal Display Using Circle Polarizing Plates A to D>

The surface sides of the λ / 4 plates 102 and 102 'of the two circular polarizing plates 103 and 103' are attached to the liquid crystal cell 107 via an adhesive, and the protective film 106, the polarizing film 101 and the λ / 4 plate are displayed from the display surface side. The liquid crystal cell 107, the λ / 4 plate 102 ', the polarizing film 101', and the protective film 106 'are stacked in this order, and the backlight 108 is placed on the side opposite to the display surface side. The formed transflective liquid crystal display device A was produced. In addition, semi-transmissive liquid crystal display devices AD were produced similarly using circularly polarizing plates B-D. In addition, the thing for 2 inches was used for the liquid crystal cell.

(Evaluation of LCD)

(1) Display quality in reflection mode

Using the spectrophotometer CM-2002 manufactured by Minolta Co., Ltd., the reflectance of the white display and the monochrome display of the liquid crystal display device were measured before and after the wet heat endurance test to calculate the contrast ratio. The results are shown in Table 3.

(2) Display quality in transmission mode

The brightness of the white display and the black display of the liquid crystal display device at the time of backlight lighting were measured before and after a wet heat endurance test using the luminance meter BM-5A manufactured by TOPCOM Corporation, and the contrast ratio was calculated. The results are shown in Table 3.

(3) moist heat endurance test

It left for 500 hours at 60 degreeC and 90% of a relative humidity.

Transflective Liquid Crystal Display A B C D The present invention For comparison ① Contrast ratio in reflection mode (initial) 14: 1 12: 1 8: 1 7: 1 (After endurance test) 12: 1 11: 1 4: 1 3: 1 ② Contrast ratio in transmission mode (initial) 110: 1 100: 1 80: 1 75: 1 (After endurance test) 105: 1 95: 1 40: 1 35: 1

Through the results shown in Table 3, the transflective liquid crystal display devices A and B using the circular polarizers A and B of the present invention are compared with the transflective liquid crystal display devices C and D using the circular polarizers C and D for comparison. It was found that the initial contrast in the transmission mode was excellent and the durability was also excellent.

The polarizing film of the present invention is excellent in durability because it is made of a polyvinyl alcohol having a high film ratio of boron atoms having a boron compound and having four crosslinking points.

Claims (5)

As a polarizing film which consists of polyvinyl alcohol hardened with the boron compound, When the polarizing film was measured by ¹¹ B-NMR using a saturated aqueous solution of boric acid as a standard, a chemical shift was observed at -3 ppm and 11 ppm, and the peak intensity of the chemical shift -3 ppm was changed to a peak intensity of 11 ppm. The division value is four or more, The polarizing film characterized by the above-mentioned. The polarizing film according to claim 1, wherein the boron compound is boric acid, and the boric acid content is 6 g / m 2 or more and less than 12 g / m 2. The protective film was affixed on at least one side of the polarizing film of Claim 1 or 2, The polarizing plate characterized by the above-mentioned. An optical compensation film formed of discotic liquid crystalline molecules is attached to the polarizing plate according to claim 3, wherein the elliptical polarizing plate is characterized in that it is attached. (a) an optical compensation film formed of liquid crystal molecules is attached to the polarizing plate of claim 3, (b) the optical compensation film comprises two layers of a first optically anisotropic layer and a second optically anisotropic layer containing a horizontally aligned rod-like liquid crystalline compound, (c) At least one of the rod-shaped liquid crystalline compounds contained in the first optically anisotropic layer and the second optically anisotropic layer is represented by the following general formula (I), General formula (I): Q1-L1-A1-L3-M-L4-A2-L2-Q2 (In the general formula (I), Q1 and Q2 each independently represent a polymerizable group, L1, L2, L3 and L4 each independently represent a single bond or a divalent linking group, and at least one of L3 and L4 is- Represents an O-CO-O- group, A1 and A2 represent a spacer group having from 2 to 20 carbon atoms, and M represents a mesogenic group.) (d) the phase difference at a measurement wavelength of 550 nm of the first optically anisotropic layer is substantially?, and the phase difference at a measurement wavelength of 550 nm of the second optically anisotropic layer is substantially? / 2, (e) An angle between the in-plane slow axis of the second optically anisotropic layer and the in-plane slow axis of the first optically anisotropic layer is 60 ± 5 °.