KR20160119159A - Optical film roll-body and method for manufacturing same, polarizing plate, and liquid crystal display device - Google Patents

Abstract

An object of the present invention is to provide a roll of an optical film in which deformation of a roll is suppressed and increase in haze is suppressed. The roll of the optical film of the present invention is a roll of an optical film obtained by winding an optical film having an embossed portion at both ends in the width direction and having a thickness of 15 to 45 탆 in the longitudinal direction of the film and the optical film is composed of a cellulose ester and 0.05 To 5% by mass of a compound represented by the following formula (1), and both side surfaces of axially opposite ends of the rolled body are wavy.

Description

TECHNICAL FIELD [0001] The present invention relates to a roll of an optical film, a method of manufacturing the same, a polarizing plate, and a liquid crystal display device.

The present invention relates to a roll of an optical film, a manufacturing method thereof, a polarizing plate, and a liquid crystal display device.

2. Description of the Related Art In recent years, the demand for liquid crystal displays in mobile devices such as smart phones and tablet terminals is increasing. Such a liquid crystal display device is required to be thin, and an optical film such as a polarizing plate protective film constituting it is required to be thin.

As the polarizing plate protective film, for example, a cellulose ester film is used. Such a film is generally produced by producing a film having a long shape by a solution casting method or the like; The film is stored as a roll obtained by winding the film on a winding core in a roll form. Then, embossed portions are formed at both end portions in the width direction of the wound-up film in order to suppress the displacement of the wound end of the film (winding displacement).

It is known that when a long film having embossed portions at both ends in the width direction is wound by a normal method, the roll body is liable to be deformed. On the other hand, a method of winding the film or winding core while periodically vibrating the film or the winding core in the width direction of the film (osylate winding) has been proposed (for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2010-150041

The inventors of the present invention have found that a rolled body is liable to be deformed particularly when a thin film is wound in a usual manner. Specifically, the deformation of the rolled body in the present invention means that the winding diameter at both end portions in the width direction of the film overlapping each other at the embossed portions is significantly larger than the winding diameter at the center portion in the widthwise direction of the film and large wrinkles are generated in the vertical direction .

The reason why the deformation of the roll body becomes remarkable particularly when the film thickness of the optical film is thin is not necessarily clear, but is considered to be as follows. That is, the thinner the film thickness of the optical film, the larger the ratio of the height of the embossed portion to the film thickness of the optical film becomes, and the difference in the winding diameter between the center portion in the width direction and both ends in the width direction becomes larger; 2) the strength of the optical film is low, and it is difficult to support the weight of the optical film.

The deformation of such a roll can be improved by performing a winding (osylate winding) method while imparting vibration as described above.

However, in the method of winding while imparting vibration, in order to vibrate the film periodically in the width direction, In particular, the film surface on which the embossing portion and the embossing portion are not formed is likely to be skewed. As a result, there is a problem that the film surface on which the embossed portion is not formed is prone to residual scratches, and the haze tends to increase. A film with increased haze tends to deteriorate the display performance such as the contrast of a liquid crystal display device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a roll of an optical film in which deformation of a roll is suppressed and increase in haze is suppressed.

[1] A roll of an optical film obtained by winding an optical film having an embossed portion at both ends in the width direction and having a thickness of 15 to 45 탆 in the longitudinal direction of the film, wherein the optical film contains cellulose ester and 100 parts by mass of the cellulose ester 0.05 to 5 parts by mass of a compound represented by the following formula (1)

(In the formula (1)

L is a combination of at least one member selected from the group consisting of ester bond, amide bond, carbonyl group, ester bond, amide bond or carbonyl group and alkylene group, nitrogen atom, oxygen atom, sulfur atom, zinc atom, calcium atom and magnesium atom A bivalent group;

R ₁ represents an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms;

R ₂ represents a hydrogen atom, an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms)

And a side surface shape of both end portions in the axial direction of the roll body is wavy.

L in Formula (1) is -C (= O) -O-, -C (= O) NH-,

_{-C (= O) -OR 3 -OC} (= O) -, -C (= O) -NH-R 3 -NH-C (= O) - (R 3 is an alkylene group having 1 to 5 carbon atoms),

C (= O) - O-M-O-C (= O) - (M is a zinc atom, a calcium atom or a magnesium atom)

_{-C (= O) -R 4 -OR} 4 -C (= O) -, -C (= O) -R 4 -SR 4 -C (= O) -, -C (= O) -R 4 - NH-R ₄ -C (= O) - (R ₄ is an alkylene group having 1 to 5 carbon atoms) and

Is a group selected from the group consisting of -C (= O) -R ₅ -C (= O) - (R ₅ is an alkylene group having 1 to 5 carbon atoms).

[3] R ₁ and R ₂ in the formula (1) are each independently a linear alkyl group having 8 to 26 carbon atoms or a straight chain alkenyl group having 8 to 26 carbon atoms [1 ] Or the optical film according to [2].

[4] The optical film roll according to any one of [1] to [3], wherein L in the formula (1) contains a sulfur atom.

[5] The optical film roll according to any one of [1] to [4], wherein the optical film further comprises an aliphatic polyester compound obtained by polycondensing an aliphatic diol and an aliphatic dicarboxylic acid.

[6] The retardation in the in-plane direction of the optical film defined by the following formula (I) and measured at a measurement wavelength of 590 nm is defined as Ro (590) (590) |? 5 nm and | Rth (590) |? 5 nm when the retardation in the thickness direction measured at 590 nm is Rth (590) A roll of the optical film described.

(I) Ro = (nx-ny) x t (nm)

Rth = {(nx + ny) / 2-nz} x t (nm)

(In the formulas (I) and (II)

nx represents a refractive index in the slow axis direction x at which the refractive index becomes the maximum in the in-plane direction of the film; ny represents a refractive index in an in-plane direction of the film in a direction orthogonal to the slow axis direction x; nz represents the refractive index in the thickness direction z of the film; t (nm) denotes the thickness of the film)

[7] A cellulose acylate film comprising a cellulose ester and 0.05 to 5 parts by mass of a compound represented by the following formula (1) based on 100 parts by mass of the cellulose ester, Preparing a film,

(In the formula (1)

L is a combination of at least one member selected from the group consisting of ester bond, amide bond, carbonyl group, ester bond, amide bond or carbonyl group and alkylene group, nitrogen atom, oxygen atom, sulfur atom, zinc atom, calcium atom and magnesium atom A bivalent group;

R ₁ represents an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms;

R ₂ represents a hydrogen atom, an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms)

And winding the optical film on the winding core in a roll form,

Wherein the step of winding includes a step of winding at least one of the optical film and the winding core on the winding core while periodically vibrating at least one of the optical film and the winding core in the width direction of the optical film Gt;

[8] A polarizing plate comprising an optical film obtained from the roll described in any one of [1] to [6].

[9] A liquid crystal display device comprising an optical film obtained from the roll described in any one of [1] to [6].

[10] A liquid crystal display comprising a first polarizing plate, a liquid crystal cell, a second polarizing plate, and a backlight in this order, wherein the first polarizing plate has a first polarizer and a second polarizer, And a protective film (F2) disposed on the side of the liquid crystal cell side of the first polarizer, wherein the second polarizer comprises a second polarizer and a liquid crystal cell side And a protective film (F4) disposed on a surface of the second polarizer opposite to the liquid crystal cell, wherein at least one of the protective films (F2 and F3) The liquid crystal display device according to [9], wherein the liquid crystal display device comprises an optical film.

[11] The liquid crystal display according to [10], wherein the liquid crystal cell is a liquid crystal cell of IPS mode or FFS mode.

[12] The liquid crystal display device according to any one of [9] to [11], wherein the length of the display area in the diagonal direction is 10 inches or less.

[13] The liquid crystal display device according to [12], further comprising a rechargeable battery.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a roll of an optical film in which deformation of a roll is suppressed and increase in haze is suppressed.

1 is a schematic diagram showing an example of a roll of an optical film of the present invention.
2 is a schematic view showing an example of the cross-sectional shape of the embossed portion.
3 is a schematic view showing an example of a winding device used in the winding process of the optical film.
4 is a graph for explaining the vibration in the vibration winding step.
5 is a schematic view showing an example of the simulation result of the integrated embossing height in the width direction of the roll of the optical film.
6 is a schematic diagram showing an example of a small-sized liquid crystal display device.
7 is a graph showing the vibration conditions in the vibration winding step in the embodiment.

As described above, deformation of the roll of the optical film can be improved by winding the optical film while oscillating the film or winding core periodically in the width direction of the film (oscillating winding). However, in the case of the oscillatory rewinding, since the optical film is periodically vibrated in the width direction, the film tends to be mutually intertwined and easily scratches on the film surface on which the embossed portion is not formed, and the haze tends to increase.

On the contrary, the inventors of the present invention have found that good slipperiness can be imparted to the film while satisfactory compatibility with the cellulose ester is caused by containing the compound represented by the formula (1) in the optical film. Thus, it has been found that the increase in the haze of the optical film can be suppressed while suppressing deformation of the roll. The present invention has been made based on this finding.

That is, the optical film of the present invention preferably contains a cellulose ester and a compound represented by the formula (1).

1. Optical film

As described above, the optical film of the present invention includes a cellulose ester and a compound represented by the formula (1).

≪ About cellulose ester >

The cellulose ester is a compound obtained by esterifying at least one of cellulose, an aliphatic carboxylic acid having 2 to 22 carbon atoms and an aromatic carboxylic acid.

Examples of cellulose esters include cellulose triacetate, cellulose diacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose benzoate, cellulose acetate benzoate and the like. Among them, cellulose acetate triacetate is preferable because of low retardation manifestation.

The total substitution degree of the acyl group of the cellulose ester is about 2.0 to 3.0, preferably 2.5 to 3.0, more preferably 2.7 to 3.0, still more preferably 2.8 to 2.95. In order to lower the phase difference manifestation, it is preferable that the total substitution degree of the acyl group is increased.

The number of carbon atoms of the acyl group contained in the cellulose ester is preferably 2 to 7, more preferably 2 to 4. From the standpoint of obtaining good heat resistance and the like, the acyl group contained in the cellulose ester preferably contains an acetyl group. The degree of substitution of the acyl group having 3 or more carbon atoms is preferably 0.9 or less, more preferably 0.

The substitution degree of the acyl group of the cellulose ester can be measured by the method described in ASTM-D817-96.

The weight average molecular weight of the cellulose ester is preferably 5.0 x 10 ⁴ to 5.0 x 10 ⁵ , more preferably 1.0 x 10 ⁵ to 3.0 x 10 ⁵ , and more preferably 1.5 10 ⁵ to 2.9 X 10 < ^{5 &} gt ;. The molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of the cellulose ester is preferably 1.0 to 4.5.

The weight average molecular weight and the molecular weight distribution of the cellulose ester can be measured by gel permeation chromatography (GPC). The measurement conditions are as follows.

Solvent: methylene chloride

Column: Three shodex K806, K805 and K803G (manufactured by Showa Denko K.K.) are connected and used.

Column temperature: 25 ° C

Sample concentration: 0.1 mass%

Detector: RI Model 504 (manufactured by GL Science)

Pump: L6000 (manufactured by Hitachi Seisakusho Co., Ltd.)

Flow rate: 1.0 ml / min

Calibration curve: standard polystyrene STK standard A calibration curve of 13 samples with polystyrene (manufactured by TOSO CORPORATION) Mw = 1.0 × 10 ⁶ to 5.0 × 10 ² is used. 13 samples are preferably selected at substantially equal intervals.

≪ Regarding the compound represented by the formula (1)

The compound represented by the formula (1) may have a function of increasing the slidability of the film.

L in formula (1) is a divalent group comprising at least an ester bond (-C (= O) O-), an amide bond (-C (= O) NH-) or a carbonyl group (-C Lt; / RTI > These carbonyl groups can impart a good affinity with the cellulose ester to the compound represented by the formula (1). Specifically, L is a group selected from the group consisting of an ester bond, an amide bond, a carbonyl group or an ester bond, an amide bond or a carbonyl group and an alkylene group, a nitrogen atom, an oxygen atom, a sulfur atom, a zinc atom, a calcium atom and a magnesium atom A divalent group obtained by combining one or more "; Amide bond or a carbonyl group and a group consisting of an alkylene group, a nitrogen atom, an oxygen atom, a sulfur atom, a zinc atom, a calcium atom and a magnesium atom from the viewpoint of obtaining a good affinity with the cellulose ester Represents a divalent group obtained by combining one or more selected from "

Examples of the "bivalent group obtained by combining one or more selected from the group consisting of an ester bond, an amide bond or a carbonyl group and an alkylene group, a nitrogen atom, an oxygen atom, a sulfur atom, a zinc atom, a calcium atom and a magnesium atom"

-C (= O) -OR ₃ -OC (= O) -, -C (= O) -NH-R ₃ -NH-C (= O) - (R ₃ is an alkylene group having 1 to 5 carbon atoms);

-C (= O) -O-M-O-C (= O) - (M is a zinc atom, a calcium atom or a magnesium atom);

_{-C (= O) -R 4 -OR} 4 -C (= O) -, -C (= O) -R 4 -SR 4 -C (= O) -, -C (= O) -R 4 - NH-R ₄ -C (= O) - (R ₄ is an alkylene group having 1 to 5 carbon atoms); And

-C (= O) -R ₅ -C (= O) - (R ₅ represents an alkylene group having 1 to 5 carbon atoms), and the like. Among them, L is preferably a group containing a sulfur atom from the viewpoint of enhancing thermal durability of the optical film, and more preferably -C (= O) -R ₄ -SR ₄ -C (= O) - .

R ₁ in the formula (1) represents an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms. The number of carbon atoms in the alkyl group and the alkenyl group is more preferably 10 or more and 26 or less, from the viewpoint of obtaining good slipperiness. The alkyl group and the alkenyl group may be linear or branched, and preferably straight-chain in that good slipperiness is easily obtained.

R ₂ in the formula (1) represents a hydrogen atom, an alkyl group having from 8 to 26 carbon atoms, or an alkenyl group having from 8 to 26 carbon atoms; In order to obtain good slipperiness, it is preferably an alkyl group of 8 to 26 carbon atoms or an alkenyl group of 8 to 26 carbon atoms. The number of carbon atoms in the alkyl group and the alkenyl group is more preferably 10 or more and 26 or less, from the viewpoint of obtaining good slipperiness. The alkyl group and the alkenyl group may be linear or branched, and preferably straight-chain in that good slipperiness is easily obtained.

When R ₂ is a hydrogen atom, -LR ₂ may be -C (= O) OH, -C (= O) NH _2, or the like.

R ₁ and R ₂ may further have a substituent such as OH group, if necessary. R ₁ and R ₂ may be the same or different.

Examples of the compound represented by the formula (1) include the following.

The content of the compound represented by the formula (1) is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the cellulose ester. When the content of the compound represented by the formula (1) is more than a certain level, sufficient slidability can be imparted to the film. Thereby, it is possible to suppress the increase of the external haze of the obtained film even if the vibration-winding step to be described later is performed. On the other hand, if the content of the compound represented by the general formula (1) is less than a certain value, it is possible to suppress the deterioration of the roll shape due to the excessively slip of the optical film.

The optical film of the present invention may further comprise a polyester compound from the viewpoint of adjusting the plasticity and phase difference of the film.

≪ Polyester compound >

The polyester compound is a compound obtained by polycondensation of a dicarboxylic acid and a diol. The dicarboxylic acid may be at least one selected from the group consisting of an aliphatic dicarboxylic acid, an alicyclic dicarboxylic acid and an aromatic dicarboxylic acid. The diol may be at least one selected from the group consisting of an aliphatic diol, an alkyl ether diol, an alicyclic diol and an aromatic diol. Among them, a dicarboxylic acid selected from the group consisting of an aliphatic dicarboxylic acid and an alicyclic dicarboxylic acid, and a group consisting of an aliphatic diol, an alkyl ether diol and an alicyclic diol Is preferably a polyester compound obtained by polycondensation of a diol selected from the group consisting of: A polyester compound (aliphatic polyester compound) obtained by polycondensing an aliphatic dicarboxylic acid and an aliphatic diol is more preferable.

That is, the polyester compound is preferably represented by the formula (2) or (3).

(2):

G in the formula (2) represents a group derived from an aliphatic diol or an alkyl ether diol. The aliphatic diol preferably has 2 to 12 carbon atoms. Examples of aliphatic diols include ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, , 1,5-pentanediol, 1,6-hexanediol, 1,5-pentylene glycol and the like, preferably ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2 Butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, and 1,6-hexanediol.

The alkyl ether diol preferably has 4 to 12 carbon atoms. Examples of the alkyl ether diol include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol and the like. The aliphatic diol or alkyl ether diol may be used alone or in combination of two or more.

A in the formula (2) represents a group derived from an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid. The number of carbon atoms of the aliphatic dicarboxylic acid is preferably 4 to 12. Examples of aliphatic dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandicarboxylic acid, dodecanedicarboxylic acid and the like . The aliphatic dicarboxylic acid or the alicyclic dicarboxylic acid may be used alone or in combination of two or more.

B ₁ in the formula (2) represents a group derived from an aliphatic monocarboxylic acid or an alicyclic monocarboxylic acid. The number of carbon atoms of the aliphatic monocarboxylic acid is preferably 1 to 12. Examples of aliphatic monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2- ethylhexanecarboxylic acid, But are not limited to, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, Saturated fatty acids such as montanic acid, melissic acid and lactic acid, unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid, and are excellent in compatibility with cellulose esters, Preferably acetic acid.

It is preferable that B ₁ , G and A in the formula (2) do not include an aromatic ring because they make it difficult to develop a phase difference. m represents a repetition number, and is preferably 1 or more and 170 or less.

Examples of the polyester compound represented by the formula (2) include those shown in Table 1.

(3):

G and A in the formula (3) are defined similarly to G and A in the formula (2), respectively. B ₂ in the formula (3) represents a group derived from an aliphatic monoalcohol or an alicyclic monoalcohol. The number of carbon atoms of the aliphatic monoalcohol is preferably 1 to 12. Examples of aliphatic monoalcohols include methanol, ethanol, propanol, isopropanol and the like; Examples of the alicyclic monoalcohols include cyclohexyl alcohol and the like.

B ₂ , G and A in the formula (3) are preferably all free of an aromatic ring from the viewpoint of making it difficult to develop a retardation. n represents the number of repeats and is preferably 1 or more and 170 or less.

Examples of the polyester compound represented by the formula (3) include those shown in Table 2.

The weight average molecular weight Mw of the polyester compound may preferably be 20,000 or less, more preferably 5000 or less, and still more preferably 3,000 or less, from the viewpoint of improving compatibility with the cellulose ester. On the other hand, the weight average molecular weight Mw of the polyester compound may be 400 or more, preferably 700 or more, and more preferably 1000 or more, from the viewpoint of inhibiting the volatilization of the polyester compound in the film.

The content of the polyester compound is preferably 1 to 45% by mass, more preferably 2 to 30% by mass, and more preferably 5 to 25% by mass, based on the cellulose ester, from the viewpoint of easy adjustment of the plasticity and retardation of the film. , And most preferably from 10 to 20 mass%.

The optical film of the present invention may further contain various additives such as an ultraviolet absorber, a plasticizer, a release aid, a matting agent (fine particle), and an impact reinforcement as necessary.

≪ About ultraviolet absorber >

The ultraviolet absorber may be a benzotriazole-based compound, a 2-hydroxybenzophenone-based compound, or a salicylic acid phenyl ester-based compound. Specific examples thereof include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis , Triazole compounds such as 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy- Phenone, and 2,2'-dihydroxy-4-methoxybenzophenone.

Examples of the ultraviolet absorber may include a commercially available tinuvin series such as Tinuvin 109, Tinuvin 171, Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328 and Tinuvin 928 from BASF Japan, (1,1,3,3-tetramethylbutyl) phenol] (Molecular Weight 659; commercially available products of ADEKA manufactured by Kabushiki Kaisha) were used in place of 2'-methylenebis [6- (2H-benzotriazol- LA31).

In the case where the optical film is used as a protective film (135 (F2) or 153 (F3) in Fig. 6 to be described later) disposed on the side of the liquid crystal cell of the polarizer, the ultraviolet ray inhibitor is not essential, The content may be about 0 to about 0.5 mass% with respect to the cellulose ester. On the other hand, in the case of being disposed on the side opposite to the liquid crystal cell of the polarizer (when used as the protective film 133 (F1) or 155 (F4) in FIG. 6 to be described later), the content of the ultraviolet ray- And may be about 1 to 5.0% by mass, preferably about 0.5 to 3.0% by mass.

≪ Matting agent >

The matting agent can impart more slidability to the optical film. The matting agent does not impair the transparency of the obtained film, and may be an inorganic compound having heat resistance in a film-forming step or a fine particle containing an organic compound.

Examples of the inorganic compound constituting the matting agent include silicon dioxide (silica), titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, Magnesium silicate and calcium phosphate. Of these, silicon dioxide and zirconium oxide are preferable, and silicon dioxide is more preferable in order to reduce an increase in haze of the resulting film.

Specific examples of the silicon dioxide include, but are not limited to, Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600, NAX50 (manufactured by Nippon Aerosil Co., (Manufactured by Nippon Silicas Co., Ltd.), Nippon Silica (manufactured by Nippon Silica Co., Ltd.), Admapine SO (Admate Inc., Tex.).

The particle shape of the matting agent is preferably amorphous, acicular, flat or spherical, and preferably spherical in that the transparency of the obtained film is easy to be improved.

The matting agent may be used alone or in combination of two or more. Further, by using particles having different particle diameters or shapes (for example, acicular and spherical shapes) in combination, highly transparent and slidable properties can be achieved at the same time.

The particle size of the matting agent is preferably smaller than the wavelength of the visible light and is preferably not more than 1/2 of the wavelength of the visible light, because the light is scattered and the transparency is lowered when the size is close to the wavelength of visible light. However, if the particle size is too small, the effect of improving the sliding property may not be exhibited. Therefore, the particle size is preferably in the range of 80 to 180 nm. The particle size means the size of the aggregate when the particles are aggregates of primary particles. When the particle is not spherical, the particle size means the diameter of the circle corresponding to the projected area.

The content of the mat agent may be about 0.05 to 1.0% by mass, preferably 0.1 to 0.8% by mass, based on the cellulose ester.

<Physical Properties of Optical Film>

(Hayes)

As described above, the optical film of the present invention includes a compound represented by the general formula (1). Thereby, the slipperiness of the film when the optical film is wound up by the oscillation winding can be increased. Thereby, it is possible to suppress an increase in haze due to the generation of residual scratches on the film surface by intertwining the films with each other.

That is, the haze of the optical film is preferably 0.5% or less, more preferably 0.3% or less. The haze of the optical film means the total haze sum of the external haze and the internal haze. If the haze of the optical film is in the above range, a good contrast tends to be obtained in the display device.

The haze of the optical film can be measured by the following procedure. That is, the film is loosened from the roll of the optical film, and cut at a uniform size in the width direction at a size of 10 points, 4 cm x 4 cm, and humidity conditioned at 23 ° C and 55% RH, respectively. The haze of the obtained film is measured with a haze meter (turbidity meter) (model: NDH 2000, manufactured by Nippon Denshoku Co., Ltd.) according to JIS K-7136. The average value of the ten measured values obtained is defined as &quot; haze &quot;.

The haze of the optical film can be adjusted depending on the kind and content of the compound represented by the formula (1). In order to lower the haze, it is preferable that the number of carbon atoms of the alkyl group or alkenyl group represented by R ₁ and R ₂ in the formula (1) is set to a certain value or more, or linearly.

(Retardation)

The in-plane retardation Ro of the optical film measured under conditions of a measurement wavelength of 590 nm and 23 占 폚 at 55% RH is preferably -10 nm or more and 10 nm or less, more preferably -5 nm or more and 5 nm or less. The retardation Rth in the thickness direction of the optical film measured under conditions of a measurement wavelength of 590 nm and 23 캜 55% RH is preferably -10 nm or more and 10 nm or less, more preferably -5 nm or more and 5 nm or less. The optical film having such a retardation value is suitable, for example, as a retardation film (F2 or F3) of an IPS mode liquid crystal display device or the like. In particular, by setting the retardation within the above range, it is possible to improve the contrast and the viewing angle of the IPS mode liquid crystal display device.

The retardations Ro and Rth are respectively defined by the following formulas.

(I): Ro = (nx-ny) xd (nm)

Rth = {(nx + ny) / 2-nz} xd (nm)

(In the formulas (I) and (II)

nx represents a refractive index in the slow axis direction x at which the refractive index becomes the maximum in the in-plane direction of the film;

ny represents a refractive index in an in-plane direction of the film in a direction orthogonal to the slow axis direction x;

nz represents the refractive index in the thickness direction z of the film;

d (nm) denotes the thickness of the film)

The retardation Ro and Rth can be determined, for example, by the following methods.

1) Humidify the optical film at 23 ° C and 55% RH. The average refractive index of the optical film after the humidity control is measured by an Abbe refractometer or the like.

2) The Ro when the light having a wavelength of 590 nm is incident on the optical film after humidity control parallel to the normal line of the surface of the film is measured with KOBRA 21ADH, Oji Keisuke Co., Ltd.

3) When light having a measurement wavelength of 590 nm is incident from an angle (incident angle (?)) With respect to the normal line of the surface of the film, the slow axis in the plane of the optical film is set as a tilting axis (rotation axis) by KOBRA 21ADH And the retardation value R ([theta]) is measured. The measurement of the retardation value R ([theta]) can be performed at six points every 10 degrees within the range of 0 DEG to 50 DEG. The in-plane slow axis is the axis at which the medium refractive index in the film plane is maximized, and can be confirmed by KOBRA 21ADH.

4) From the measured values of Ro and R (?) And the above-described average refractive index and film thickness, nx, ny and nz are calculated by KOBRA 21ADH to calculate Rth at a measurement wavelength of 590 nm. The measurement of the retardation can be performed under conditions of 23 占 폚 and 55% RH.

(thickness)

The thickness of the optical film is preferably 15 to 45 占 퐉, and preferably 15 to 28 占 퐉 in terms of thinning of the polarizing plate, roll shape, and haze of the film.

2. Roll of optical film

The roll of the optical film of the present invention is obtained by winding a long optical film in the longitudinal direction of the film.

1 is a schematic diagram showing an example of a roll of an optical film of the present invention. Fig. 1 (a) is a view showing an example of the appearance of a roll body; 1 (b) is a partial sectional view (A-A line sectional view) along the axial direction in Fig. 1 (a). 1 (a), a roll 10 of an optical film includes a winding core 11, an elongated optical film 12 wound around the winding core 11 and having an embossed portion 13A at both ends in the width direction, Film (13).

In the present invention, the optical film is wound while vibrating at least one of the film or the winding core in the width direction of the film. Therefore, the obtained rolled body 10 includes the laminated portion so that the embossed portions 13A after winding do not completely overlap each other. As a result, the side surfaces of both end portions in the axial direction of the roll body 10 are wavy. As shown in Fig. 1 (b), when the side surfaces of the both ends in the axial direction of the roll body 10 are wavy, the axial end portions of the cross section along the axial direction of the roll body are wavy .

The embossed portions 13A are formed at both ends of the optical film 13 in the width direction. The width of the embossed portion 13A may be, for example, 0.2 to 6%, preferably 0.3 to 2% with respect to the entire width of the optical film 13. [ Specifically, it may be about 0.5 to 30 mm, preferably 5 to 30 mm, and more preferably 6 to 20 mm. If the width of the embossed portion 13A is too small, there is a tendency that the transportability of the optical film 13 is not sufficiently improved or the winding deviation can not be suppressed sufficiently. On the other hand, if the width of the embossed portion 13A is excessively large, the ratio that can be used as the optical film tends to be small.

The height of the convex portion constituting the embossed portion 13A may be about 5 to 60% of the film thickness of the optical film 13. Specifically, the height of the convex portion constituting the embossed portion 13A may be preferably 1.0 to 10.0 mu m, and more preferably 1.0 to 6.0 mu m. The height of the convex portion refers to the height from the film surface on which the embossing is not formed to the apex of the convex portion. If the height of the embossed portion 13A is excessively low, there is a possibility that winding displacement in the rolled body can not be sufficiently suppressed. If the embossed portion 13A is too high, the area where the embossed portion of the roll is superimposed tends to be thicker than the other area. Therefore, even if the above-described vibration-winding step is carried out, there is a fear that the deformation of the rolled body can not be sufficiently suppressed.

2 is a schematic diagram showing an example of the cross-sectional shape of the embossed portion 13A. Examples of the cross-sectional shape of the embossed portion 13A include a rectangular shape (Fig. 2 (a)); A shape in which a widthwise central portion of the embossed portion 13A is formed with a concave portion a lower than both widthwise ends is formed (Fig. 2 (b)); The convex portion b in the widthwise central portion of the embossed portion includes a plurality of convex portions b and c and the convex portion b in the widthwise middle portion includes a shape do. As described above, by reducing the central portion in the width direction of the embossed portion, the overlapping of the central portion in the width direction of the embossed portion can be reduced. Thus, it is considered that the increase in the thickness of the embossed portion of the rolled body can be reduced and the deformation of the rolled body can be further suppressed.

The width of the optical film 13 may be, for example, 1000 to 6000 mm, preferably 1400 to 4000 mm. The winding length of the optical film 13 may be, for example, 100 to 10000 m.

3. Method for manufacturing roll of optical film

The roll of the optical film of the present invention comprises the steps of 1) preparing a long optical film having embossed portions at both ends in the width direction, and 2) winding the optical film. And 2) the step of winding the optical film includes a step of winding the optical film on the winding core while vibrating at least one of the optical film and the winding core periodically in the width direction of the film (vibration winding step) desirable.

&Lt; Regarding the step of preparing an optical film having a long shape >

The elongated optical film is produced by a solution casting method (casting) or a melt casting method (melt); In order to reduce the failure of the striped pattern, and the like, preferably, it can be produced by the solution casting method (casting).

A method of producing an elongated optical film by a solution casting method (casting) comprises the steps of: 1-1) obtaining a dope containing a cellulose ester, 1-2) softening the dope on a support, 1-3) a step of peeling the film-like material from the support; and 1-5) a step of forming an embossed portion at both ends in the width direction of the peeled film-like material; The method may further comprise the step of (1-4) stretching the film-like material between (1-3) above and (1-5) as necessary.

1-1) Dissolution Process

The organic solvent used for preparing the dope may be any solvent as long as it dissolves each of the above components such as cellulose ester. Examples of the chlorinated organic solvent include methylene chloride. Examples of the non-chlorine-based organic solvent include methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate and the like. Among them, methylene chloride is preferable.

The dope preferably further comprises, in addition to the organic solvent, 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. By containing an aliphatic alcohol, the film-like material is gelled, and peeling from the metal support is facilitated. Examples of the straight chain or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol. Of these, methanol and ethanol are preferable in that the dope is relatively stable, the boiling point is relatively low, and the drying property is also good.

The dissolution of the cellulose ester and the like may be carried out by a method of performing the reaction at normal pressure, a method of performing the reaction at the boiling point or lower of the main solvent, a method of performing the reaction at the boiling point of the main solvent or the like.

1-2) Flexible process

The dope liquid is fed by a pressure die through a liquid delivery pump (for example, a pressurized metering gear pump). Then, the dope liquid is plied from the slit of the pressure die to the flexible position of an endless metal support body (for example, a stainless steel belt, a rotating metal drum, or the like)

1-3) Solvent evaporation and peeling process

The softened dope liquid on the metal support is heated on the metal support to evaporate the solvent in the dope liquid to obtain a film-like product.

In order to evaporate the solvent, there are a method of blowing air from the side of the dope liquid surface, a method of transferring heat from the back surface of the support through liquid, a method of transferring heat from the front and rear sides by radiant heat, Do. Particularly, when a film is formed using a stainless steel belt, it is preferable to dry the dope liquid on the metal support under an atmosphere within the range of 40 to 100 占 폚. In order to maintain the atmosphere within the range of 40 to 100 DEG C, it is preferable to heat the warm air at this temperature to the dope liquid surface on the metal support or to heat it by means of infrared rays or the like. Further, in the case of film formation using a metal drum, it is preferable that the surface temperature of the metal drum is set to -20 to 10 캜, and the film is peeled off without drying on the metal drum.

The film-like material obtained on the metal support is peeled off at the peeling position. When a film is formed using a stainless steel belt, the temperature of the metal support at the peeling position is preferably in the range of 10 to 40 占 폚, and more preferably in the range of 11 to 30 占 폚. In the case of film formation using a metal drum, the temperature of the metal support at the peeling position is preferably in the range of -20 to 10 占 폚.

The amount of residual solvent of the film-like material on the metal support at the time of peeling may be, for example, in the range of 50 to 120 mass%. The amount of the residual solvent in the film-like product is defined by the following formula.

Residual solvent amount (%) = (mass before heat treatment of film material-mass after heat treatment of film material) / (mass after heat treatment of film material) 占 100

The heat treatment at the time of measuring the residual solvent amount means that the heat treatment is performed at 140 占 폚 for 1 hour.

The peeling tension at the time of peeling the metal support and the film is usually in the range of 196 to 245 N / m, but it is preferable to peel off with a tensile force of 190 N / m or less when wrinkles tend to enter at peeling, It is more preferable to peel off with a tensile force of.

1-4) Drying and drawing process

The peeled film-like material is dried while being conveyed in the tenter stretching device, or dried while being conveyed by a plurality of rollers arranged in the drying device. The drying method is not particularly limited, but a method of blowing hot air on both surfaces of the film-like material is generally used.

It is preferable that the rapid drying is performed under the condition that the residual solvent is not more than 8% by mass, since the planarity of the resulting film is liable to be impaired. Through the entire drying process, the drying temperature is preferably in the range of 40 to 190 占 폚, more preferably in the range of 40 to 170 占 폚.

The film-like material obtained after drying may be further stretched if necessary. The film-like material is preferably stretched in at least one direction of the film width direction (TD direction), the transport direction (MD direction), or the oblique direction; And more preferably in the width direction (TD direction). When the film is stretched in both the width direction (TD direction) and the transport direction (MD direction), the stretching in the width direction (TD direction) and the stretching in the transport direction (MD direction) You can do it.

The stretching ratio may be, for example, 1.01 to 1.5 times, preferably 1.01 to 1.3 times in each direction.

When stretching is carried out in the tenter stretching apparatus, the amount of the residual solvent in the film material at the start of the tenter stretching is preferably 2 to 30% by mass. The drying is preferably carried out until the residual solvent amount of the film-like material becomes 10 mass% or less, preferably 5 mass% or less. The drying temperature is preferably in the range of 30 to 160 ° C, more preferably in the range of 50 to 150 ° C. The tenter system includes a clip tenter and a pin tenter, but in the present invention, a pin tenter is preferable from the viewpoint of productivity.

1-5) Embossing forming process

It is preferable to form embossed portions at both end portions in the width direction of the film in order to facilitate winding of the obtained film. The method of forming the embossed portion is not particularly limited, and examples thereof include a method of forming an embossed portion by pressing a roller such as an embossing ring on the film, and a method of forming an embossed portion in a noncontact manner. Examples of the method of forming the embossed portion in a noncontact manner include a method of forming an embossed portion by irradiating the film with laser light; A method in which a liquid material is applied by an inkjet method to form an embossed portion.

&Lt; About winding process >

The winding step preferably includes a step of winding at least one of the optical film and the winding core on the winding core while vibrating the film periodically in the width direction of the film (vibration winding step).

3 is a schematic view showing an example of the winding device 20 used in the winding process of the optical film. 3 (a) is a side view of the winding device 11 taken along the axial direction of the winding device 20, and FIG. 3 (b) is a plan view of the optical film 13 as viewed from above.

The winding device 20 includes a vibration control device 21 for controlling the vibration of the winding core 11, a guide roller 23 for guiding the optical film 13 to the winding core 11, And a touch roller 25 for pressing the optical film 13 wound on the optical film 11.

The winding core 11 is rotatably provided by a rotating device (not shown). The vibration control device 21 is configured to impart vibration that changes the relative position between the optical film 13 and the winding core 11 and to control the vibration state thereof.

The guide roller 23 is a member which is driven to rotate by the running of the optical film 13. Thereby, the running optical film 13 is guided to the winding core 11, the wobbling of the traveling position of the optical film 13 is reduced by the guide roller 23, and the optical film 13 is wound around the winding core 11. [ (11).

The touch roller 25 is a member that is driven to rotate by the rotation of the winding core 11. Thereby, the optical film 13 wound on the winding core 11 is pressed so that the wound optical film 13 can be prevented from being separated from the winding core 11.

In the winding device 20 constructed as described above, the optical film 13 is guided to the surface of the winding core 11 by the guide roller 23. [ Then, the winding core 11 is rotated by a rotating device (not shown), and the guided optical film 13 is wound around the winding core 11.

In the present invention, it is preferable that the winding step of winding the optical film (13) on the winding core (11) includes a vibration winding step. In the vibration-winding step, vibration that changes the relative positions of the optical film 13 and the winding core 11 in the width direction of the optical film 13 is applied. The vibration condition can be controlled by the vibration control device 21. [ 3B shows an example in which the winding core 11 is vibrated. However, the optical film 13 and the winding core 11 need only a vibration whose relative position in the width direction changes, and the optical film 13 ); Both the optical film 13 and the winding core 11 may be vibrated.

4 is a graph for explaining vibration in the vibration winding step. The x-axis in the graph of Fig. 4 represents the integrated thickness (mm) of the wound optical film at the position of the optical film to be wound on the winding core. That is, the distance between the outermost surface of the wound optical film 13 and the surface of the winding core 11 corresponds to the integrated thickness (x) of the optical film 13 in FIG. The y-axis of the graph of Fig. 4 indicates the distance between the center position in the width direction of the optical film 13 and the center position in the width direction of the winding core 11 (the distance between the centers of the optical film 13 and the winding core 11 (mm); Corresponds to the center-to-center distance y in Fig.

The vibration in the vibration winding step may be sinusoidal vibration as indicated by the curve 52 in Fig. 4; A square-wave vibration as indicated by a curve 53; Or may be a vibration as indicated by the curve 51. Above all, the vibration as indicated by the curve 51 is preferable from the viewpoint of making the side surface of the roll body less prone to scratches and the like. Specifically, a function representing a sine wave oscillation of an amplitude A and a period T as represented by a curve 52 is a (x); B (x) is a function representing the square wave oscillation of amplitude (A) and period (T) as indicated by curve 53; The function f (x) and the area enclosed by the x axis correspond to the function a (x), where a function representing the vibration of the amplitude A and the period T as represented by the curve 51 is f ) And a function f (x) which is larger than the area surrounded by the x-axis and smaller than the area surrounded by the function b (x) and the x-axis. In the case where no vibration is applied, it is a function represented by the straight line 54 on the x-axis in Fig.

Fig. 5 is a schematic view showing an example of the simulation result of the integrated embossing height in the width direction of the roll of the optical film. Fig. The x-axis in Fig. 5 indicates the position in the width direction of the roll of the optical film; The y-axis represents the integrated embossing height.

As shown in Fig. 5, when vibration is not applied, the graph is represented by a line 57; (In the case where the amplitude A is equal to or smaller than the width of the embossed portion), the graph is represented by the line 56; In the case of oscillating so as to be the function f (x), the graph is represented by the line 55. [

In the case where no vibration is applied, the embossing portion is laminated at the same position in the width direction of the film as indicated by a line 57, so that the integrated embossing height becomes a value obtained by integrating the number of times the embossing portion is wound up to the height of the embossing portion . On the other hand, in the case where vibration is imparted to the function a (x), although the overlap of the embossed portions increases in the vicinity of the center position of the amplitude A of vibration as indicated by the line 56, The integrated embossing height can be reduced. In addition, when the vibration is imparted to the function f (x), the residence time when the absolute value of the y displacement of the vibration is large becomes relatively long, so that the overlap of the embossed portion in the roll body can be effectively Can be reduced. As described above, the roll of the optical film wound by the vibration winding process can sufficiently suppress the occurrence of deformation even after long-term storage.

The function f (x) may be a function in which the period T of the vibration or the amplitude A periodically fluctuates. Specifically, the function f (x) may be a periodic function that f (x) = f (x + T) holds; The function f (x) may be a function in which the period T of oscillation gradually decreases as the integrated thickness x of the optical film increases; The function f (x) may be a function that the amplitude (A) of the vibration gradually increases as the integrated thickness (x) of the optical film increases.

In particular, from the viewpoint of obtaining a roll of an optical film in which the occurrence of deformation is further suppressed, it is preferable that the amplitude A of the vibration is increased gradually as the integrated thickness of the optical film 13 increases. If the amplitude of the vibration is large, it is considered that the overlapping of the embossed portion can be further suppressed and the occurrence of deformation can be further suppressed. The deformation of the rolled body can be sufficiently suppressed even when a vibration having a small amplitude is applied because the total thickness at the beginning of winding is small at the beginning of winding and deformation of the rolled body is difficult to occur. On the other hand, if the integrated thickness of the wound optical film increases as the optical film is wound around the winding core, deformation of the rolled body tends to occur. In this way, when the integrated thickness of the wound optical film is large and deformation of the roll is likely to occur, by applying a large amplitude vibration, the superimposition of the embossed portion can be effectively reduced and deformation of the rolled body can be further suppressed I think.

Further, it is preferable that the period T of vibration is made smaller gradually as the thickness of the integration of the optical film becomes larger. If the cycle of vibration is small, it is considered that the load applied to the optical film can be reduced. When the integrated thickness of the wound optical film increases as the optical film is wound, the deformation of the rolled body tends to occur. In this way, when the integrated thickness of the wound optical film is large and deformation of the rolled body is likely to occur, the load on the optical film can be effectively reduced by applying a vibration with a small cycle, It can be suppressed.

The amplitude (A) of the vibration is preferably 0.1 to 1.0%, more preferably 0.35 to 0.70% of the film width. Specifically, it may be about 2 to 15 mm, preferably about 4 to 10 mm. If the amplitude A is equal to or larger than a predetermined value, overlapping of the embossings can be easily reduced, and deformation of the roll body can be suppressed well. If the amplitude A is less than a predetermined value, the sides of both end portions in the axial direction of the roll body do not wobble largely, and the movement distance of the film per unit time does not excessively increase, and excessive increase in haze can be suppressed.

The period (T) of vibration is preferably 0.2 to 10%, more preferably 0.3 to 6% of the film width. Concretely, it can be set to about 3 to 120 mm. If the period T is equal to or larger than a predetermined value, the lateral sides of both end portions in the axial direction of the roll do not wobble largely, and the moving distance of the film per unit time does not excessively increase, and excessive increase in haze can be suppressed. If the period T is less than a predetermined value, deformation of the roll body can be suppressed well.

The winding step may include the above-described vibration winding step, and all of the winding steps may be a vibration winding step; Another winding process may be further included. Another example of the winding process includes a process (nonvibrating winding process) for winding the center-to-center distance y without fluctuation. The non-vibrating winding process and the vibration winding process can be arbitrarily combined.

For example, it is preferable to perform the non-vibrating winding step at the beginning of winding, the vibration winding step at the middle, and the non-vibration winding step at the end of winding. That is, in the initial stage of winding, the non-vibrating winding step can be performed in that the total thickness of the optical film is small and deformation of the roll body is difficult to occur. On the other hand, as the optical film is wound up and the integrated thickness of the wound optical film becomes larger, the wound roll body is liable to be deformed. In such a case, deterioration of the roll shape can be effectively reduced by carrying out the vibration winding step. Further, by performing the non-vibrating winding step at the end of winding, the optical film can be smoothly released when the optical film is unwound from the roll. For example, when the winding stage is a vibrated winding stage, when the optical film is started to be unwound from the obtained roll, the optical film may not smoothly loosen due to snaking or the like. On the other hand, by performing the non-vibrating winding step at the end of winding, the optical film can be smoothly released immediately after the optical film starts to be unwound from the roll.

As described above, the rolled body of the optical film of the present invention is obtained through a step (a vibration winding step) of winding at least one of the optical film and the winding core on the winding core while vibrating the film periodically in the width direction of the film. Thereby, the overlapping of the embossed portions can be reduced and the difference in the winding diameter between the both end portions in the width direction and the central portion in the width direction can be reduced, as compared with the roll body obtained only by the non- As a result, the optical film of the present invention can suppress the deformation of the rolled body even though the film thickness is very thin. By suppressing the deformation of the rolled body, it is possible to suppress the deterioration of the optical characteristics due to uneven tension applied to the optical film or non-uniform film thickness.

Particularly, when the optical film contains an aliphatic polyester compound, the strength of the optical film tends to be lowered, and deformation of the roll is liable to occur. Even in such a case, deformation of the rolled body can be preferably suppressed by performing the above-described vibration-winding step.

Further, in the vibration winding step, the optical films; In particular, the surface of the optical film on which the embossed portion and the embossed portion are not formed is likely to be stuck to each other, whereby the surface of the optical film on which the embossed portion is not formed tends to be scratched. On the other hand, the optical film of the present invention contains the compound represented by the general formula (1), so that it can have good slidability. Thereby, even if the embossed portion and the optical film surface on which the embossed portion is not formed are stuck to each other, the optical film surface on which the embossed portion is not formed is prevented from being scratched, and the increase in haze (external haze) can be suppressed. As a result, the yield of optical films and polarizing plates can be increased.

4. Polarizer

The polarizing plate of the present invention comprises a polarizer and two protective films for holding the polarizer.

<About Polarizer>

The polarizer is a device that passes only light of a polarization plane in a certain direction, and a typical polarizer currently known is a polyvinyl alcohol polarizing film. The polyvinyl alcohol polarizing film includes a polyvinyl alcohol film stained with iodine and a dichroic dye stained.

The polyvinyl alcohol polarizing film may be a film obtained by uniaxially stretching a polyvinyl alcohol film and then dyed with iodine or a dichroic dye (preferably a film subjected to further durability treatment with a boron compound); The film may be a uniaxially stretched film (preferably a film obtained by further durability treatment with a boron compound) after dyeing a polyvinyl alcohol film with iodine or dichromatic dye.

The thickness of the polarizer is preferably from 2 to 30 占 퐉, and more preferably from 5 to 15 占 퐉, from the viewpoint of thinning the polarizing plate.

&Lt; Protective film >

At least one of the two protective films sandwiching the polarizer is preferably an optical film obtained from the roll of the optical film of the present invention. The other of the two protective films may be another protective film.

Examples of other protective films include a (meth) acrylic resin film, a polyester film, a cellulose ester film and the like, preferably a cellulose ester film. The cellulose ester contained in the cellulose ester film is defined similarly to the cellulose ester contained in the above-mentioned optical film, and may be preferably cellulose triacetate.

The retardation Ro in the in-plane direction, which is measured under the conditions of a measurement wavelength of 590 nm and 23 占 폚 and 55% RH, is preferably 0 to 20 nm, more preferably 0 to 10 nm. The retardation Rt in the thickness direction of the protective film measured under the conditions of a measurement wavelength of 590 nm and 23 占 폚 55% RH is preferably 0 to 80 nm, more preferably 0 to 50 nm.

The thickness of the other protective film may be about 10 to 100 mu m, preferably 10 to 80 mu m.

The polarizing plate of the present invention can be obtained, for example, by a step of bonding the optical film of the present invention to at least one side of a polarizer with an adhesive. The adhesive to be used for bonding may be a completely saponified polyvinyl alcohol aqueous solution (water-soluble) or an active energy ray-curable adhesive. It is preferable to use an active energy ray-curable adhesive because the elasticity of the obtained adhesive layer is high and the dimensional change of the polarizing plate is easily suppressed.

The active energy ray curable adhesive composition may be a photo radical polymerization type composition using photo radical polymerization, a photo cation polymerization type composition using photo cation polymerization or a hybrid type composition using photo radical polymerization and photo cation polymerization in combination.

The photo-radical polymerization type composition can be a composition containing a radical polymerizing compound containing a polar group such as a hydroxyl group or a carboxyl group and a radical polymerizing compound containing no polar group in a specific ratio as disclosed in Japanese Patent Application Laid-Open No. 2008-009329 have. The radical polymerizing compound is preferably a compound having a radically polymerizable ethylenically unsaturated bond. Preferable examples of the compound having a radically polymerizable ethylenically unsaturated bond include a compound having a (meth) acryloyl group. Examples of the compound having a (meth) acryloyl group include N-substituted (meth) acrylamide-based compounds, (meth) acrylate-based compounds and the like. (Meth) acrylamide means acrylamide or methacrylamide.

The cationic cationically polymerizable composition is a cationically polymerizable composition comprising (a) a cationic polymerizable compound, (b) a cationic photopolymerization initiator, (γ) a maximum cationic polymerization initiator in light having a wavelength longer than 380 nm as disclosed in Japanese Patent Application Laid- A photosensitizer exhibiting absorption, and a composition containing each component of (?) Naphthalene-based photosensitizer or the like.

Such a polarizing plate includes, for example, a step of performing an adhesion facilitating treatment (corona treatment, plasma treatment, or the like) on the surface of the optical film; Applying an active energy ray-curable adhesive to at least one of the polarizer and the optical film; Bonding the polarizer and the optical film via the obtained adhesive layer; And then curing the adhesive layer in a state in which the polarizer and the optical film are bonded to each other.

5. Liquid crystal display

A liquid crystal display device of the present invention includes a first polarizing plate, a liquid crystal cell, a second polarizing plate, and a backlight in this order. At least one of the first and second polarizing plates may be a polarizing plate of the present invention. In the polarizing plate of the present invention, it is preferable that the optical film of the invention is disposed on the liquid crystal cell side.

Specifically, the first polarizing plate comprises a first polarizer, a protective film F1 disposed on a surface opposite to the liquid crystal cell of the first polarizer, a protective film F2 disposed on a surface of the first polarizer facing the liquid crystal cell ). The second polarizer includes a second polarizer, a protective film (F3) disposed on the side of the liquid crystal cell side of the second polarizer, and a protective film (F4) disposed on the side opposite to the liquid crystal cell of the second polarizer . At least one of the protective films F1, F2, F3 and F4; Preferably, at least one of F2 and F3 is an optical film obtained from a roll of the optical film of the present invention.

The liquid crystal display device of the present invention may be a medium or large liquid crystal display device such as a television or a notebook computer; Or a small liquid crystal display device such as a smart phone. Among them, a liquid crystal display device is preferably a small-sized liquid crystal display device in which the length in the diagonal direction of the display region (not shown) is 10 inches or less, preferably 5 inches or less in that the effect of the present invention is easily obtained Do.

6 is a schematic diagram showing an example of a small-sized liquid crystal display device. 6, the small liquid crystal display device 100 includes a liquid crystal cell 110, a first polarizer plate 130 and a second polarizer plate 150 sandwiching the liquid crystal cell 110, and a backlight 170; A touch panel unit 210 disposed between the first polarizing plate 130 and the liquid crystal cell 110 and a backlight 170 disposed between the first polarizing plate 130 and the liquid crystal cell 110. The cover glass 190 is disposed on the viewing side of the first polarizing plate 130, And a rechargeable battery 230 disposed on the back side of the rechargeable battery.

The display mode of the liquid crystal cell 110 may be various display modes such as STN, TN, OCB, HAN, VA (MVA, PVA), IPS and FFS (Fringe Field Switching) , An IPS mode, or an FFS mode.

The first polarizing plate 130 is disposed on the viewer-side surface of the liquid crystal cell 110; A protective film 133 (F1) disposed on the side opposite to the liquid crystal cell 110 of the first polarizer 131 and a protective film 133 (F1) disposed on the opposite side of the liquid crystal cell 110 of the first polarizer 131, And a protective film 135 (F2) disposed on the side of the protective film 135 (F2). The second polarizing plate 150 is disposed on the backlight side surface of the liquid crystal cell 110; The protective film 153 (F3) disposed on the side of the liquid crystal cell 110 side of the second polarizer 151 and the liquid crystal cell 110 of the second polarizer 151 And a protective film 155 (F4) disposed on the opposite side. In Fig. 6, both of the protective films 135 (F2) and 153 (F3) may include an optical film obtained from the roll of the present invention.

The touch panel unit 210 is disposed between the liquid crystal cell 110 and the first polarizer 130 (on-cell type). However, the arrangement of the touch panel unit 210 is not limited to that shown in Fig. 6, and the touch panel unit 210 may be integrally provided (cover glass integral type) on the cover glass 190; Or may be provided inside the liquid crystal cell 110 (in-cell type).

The rechargeable battery 230 may be, for example, a lithium ion secondary battery.

As described above, both of the protective films 135 (F2) and 153 (F3) may include an optical film obtained from the roll of the present invention. In the roll of the present invention, the deformation of the roll is suppressed even though the film thickness of the optical film is extremely small. Therefore, uneven tension is applied to the optical film due to the deformation of the roll, thereby suppressing a deterioration in display performance caused by uneven phase difference in the optical film or non-uniform film thickness.

Further, in a liquid crystal display device, a high temperature is liable to be caused by the heat of the backlight. In particular, the small liquid crystal display device as shown in Fig. 6 includes a rechargeable battery 230 that emits heat at the time of charging and discharging, and since the apparatus volume is small, the apparatus tends to have a high temperature of 50 DEG C or more. In the present invention, the compound represented by the general formula (1) further contains a sulfur atom, so that the thermal durability of the film can be increased. Thereby, the protective films 135 (F2) and 153 (F3) also have good durability and can maintain good display performance even in a small-sized liquid crystal display device in which the device temperature is 50 DEG C or higher. Further, it is preferable that the compound represented by the general formula (1) contains a sulfur atom in addition to the heat of the backlight and the heat at the time of charging / discharging as well as in a high temperature environment because the durability of the film can be enhanced.

<Examples>

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

1. Material of optical film

<Cellulose Ester>

Cellulose triacetate (acetyl group degree of substitution: 2.85, weight average molecular weight Mw: 285000)

&Lt; Compound represented by the formula (1) >

&Lt; Comparative compound >

&Lt; Polyester compound >

2. Fabrication of optical film

&Lt; Example 1 >

(Preparation of fine particle addition liquid)

11 parts by mass of fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) and 89 parts by mass of ethanol were mixed with a dissolver for 50 minutes with stirring, and then dispersed in mannitol to obtain a fine particle dispersion.

Subsequently, 99 parts by mass of methylene chloride was added to the dissolution tank, and 5 parts by mass of the prepared fine particle dispersion was slowly added while sufficiently stirring. The resulting solution was dispersed by an attritor so that the particle size of the secondary particles became a predetermined size, and then filtered with Fine Mat NF manufactured by Nippon Segasenk Co., Ltd. to obtain a particulate addition liquid.

(Preparation of dope solution)

Using the obtained particulate additive liquid, a dope liquid having the composition shown below was prepared. First, the following components were put in a sealed container, heated to 70 DEG C, and the cellulose ester was completely dissolved while stirring. The obtained solution was filtered using Azumi filter paper No. 244 manufactured by Azumi Co., Ltd. to obtain a dope solution.

(Composition of Dope Solution)

Cellulose ester (cellulose triacetate having an acetyl substitution degree of 2.85, Mw: 285000): 100 parts by mass

Polyester compound K1: 15 parts by mass

Compound 1-1 (compound represented by the formula (1)): 1 part by mass

Fine particle addition liquid: 0.2 mass part (solid content)

Methylene chloride: 475 parts by mass

Ethanol: 50 parts by mass

The obtained dope was uniformly softened on a stainless steel band support at 22 DEG C at a dope temperature of 35 DEG C by using a belt softener. Thereafter, the dope liquid on the support was dried to a releasable range, and then peeled off from the stainless band support to obtain a film-like product. The residual solvent amount of the dope at the time of peeling was 25%.

The film-like material thus obtained was dried at 120 DEG C while being stretched in the transverse direction (TD direction) at a draw ratio 1.01 times with a tenter. Then, the film was dried at 120 DEG C while being conveyed in a plurality of rolls, and then knurled at both ends of the film to a width of 10 mm and a height of 5 mu m to produce a film having a width of 1400 mm and a film thickness of 20 mu m.

The knurled film thus obtained was wound into a rolled form while the wound core was vibrated in the film width direction using a winding device as shown in Fig. 3 to obtain a rolled body. Specifically, the roll 101 was obtained by winding 2900 m of the film 101 at a speed of 80 m / min, a tension of 140 N at the beginning of winding, a tension of 90 N at the end of winding, and a nip force of 20 N of the touch roller. The vibration condition in the vibration winding step was set to a condition of a period T = 80 mm and an amplitude A = 5 mm (Oscillation A) satisfying the function f (x) shown by the curve 61 in Fig. The side surfaces of both end portions in the axial direction of the obtained roll were wavy. The curve 62 in Fig. 7 also shows sinusoidal oscillations in which the period T and A are the same as above.

&Lt; Example 2 >

Except that the vibration condition of the vibration winding step was changed to a condition (oscillation B) of a period T = 5 mm and an amplitude A = 8 mm satisfying a function f (x) represented by a curve 51 in Fig. , A roll 102 of a film was obtained.

&Lt; Comparative Example 1 &

A roll 103 of a film was obtained in the same manner as in Example 1 except that the produced film was wound (straightened) without winding the wound core.

&Lt; Comparative Example 2 &

A film was prepared in the same manner as in Example 1 except that the compound represented by the formula (1) was not added. A film roll 104 was obtained in the same manner as in Example 1, except that the obtained film was wound by straight winding without causing the winding core to vibrate.

&Lt; Comparative Example 3 &

A film was produced in the same manner as in Example 1 except that the compound represented by the formula (1) was not contained, and a roll 105 was obtained.

&Lt; Comparative Example 4 &

A film was prepared in the same manner as in Example 1 except that the compound represented by the formula (1) was not contained and the content of the silica particles as a matting agent was changed to 2 mass%, and a roll 106 was obtained.

&Lt; Examples 3 to 6 and Comparative Example 5 >

A film was prepared in the same manner as in Example 1 except that the film thickness of the obtained film was changed as shown in Table 4, and rolls 107 to 111 were obtained.

&Lt; Example 7 >

A film was prepared in the same manner as in Example 1 except that the content of the polyester compound K1 was changed to 5 parts by mass to obtain a roll 112.

&Lt; Examples 8 to 12 and Comparative Example 6 >

A film was produced in the same manner as in Example 4 except that the content of the compound represented by the formula (1) was changed as shown in Table 4, and the rolls 113 to 118 were obtained.

&Lt; Comparative Example 7 &

A film was produced in the same manner as in Comparative Example 2 except that the polyester compound was not added, and a roll 119 was obtained.

&Lt; Examples 13 to 25 and Comparative Examples 8 to 9 >

A film was produced in the same manner as in Example 1 except that the kind of the compound represented by the formula (1) was changed as shown in Table 5, and the rolls 120 to 134 were obtained.

The production conditions of the films of Examples 1 to 12 and Comparative Examples 1 to 7 are shown in Table 4; The production conditions of the films of Examples 13 to 25 and Comparative Examples 8 to 9 are shown in Table 5.

The shape of the obtained roll, the haze, the retardation and the heat durability of the film were evaluated by the following methods.

(The shape of the roll)

The surface morphology of the obtained roll was visually observed and evaluated according to the following criteria.

◎: No wrinkles appear on the surface of the roll

○: Weak wrinkles appear on a part of the surface of the roll

?: Wrinkles and concave portions are seen on the entire surface of the roll surface

X: There is noticeable deterioration in the vicinity of the roll surface, and wrinkles and depressions are seen on the entire surface

XX: The roll surface has a remarkable shape deterioration, and wrinkles and concave portions are seen on the entire surface, and the shape of the roll is degraded to the inside thereof

&Lt; / RTI &gt; were judged to be substantially problem-free levels.

(Hayes)

The film was loosened from the obtained rolls and cut into 10-point size, 4 cm x 4 cm, at regular intervals in the width direction, and each was humidity-conditioned at 23 ° C and 55% RH. The haze of the obtained film was measured with a haze meter (turbidimeter) (model: NDH 2000, manufactured by Nippon Denshoku Co., Ltd.) in accordance with JIS K-7136, and the average value of ten points was determined.

?: Haze value is not more than 0.3%

○: The haze value is more than 0.3% and less than 0.4%

?: Haze value is more than 0.4% and not more than 0.5%

X: Haze value exceeded 0.5%

&Lt; / RTI &gt; were judged to be substantially problem-free levels.

(Phase difference Ro, Rth)

1) The film was loosened from the obtained roll, and the film cut out from the central portion in the width direction was humidity-conditioned at 23 DEG C and 55% RH. The average refractive index of the film after humidity control was measured with an Abbe refractometer or the like.

2) Ro was measured with KOBRA 21ADH, Oji Keisuke Co., Ltd. when light having a measurement wavelength of 590 nm was incident on the film after humidity control parallel to the normal line of the surface of the film.

3) The retardation value (a value when the light with a measurement wavelength of 590 nm was incident from an angle (incident angle (?)) With respect to the normal line of the film surface with the slow axis in the plane of the film as a tilting axis (rotation axis) by KOBRA 21ADH R ([theta]) was measured. The retardation value R ([theta]) was measured at 6 points every 10 DEG in the range of 0 DEG to 50 DEG. The surface axis in the plane of the film was confirmed by KOBRA 21ADH.

4) From the measured values of Ro and R (?) And the above-described average refractive index and film thickness, nx, ny and nz were calculated by KOBRA 21ADH to calculate Rth at a measurement wavelength of 590 nm. The measurement of the retardation was carried out under conditions of 23 캜 and 55% RH.

(Heat durability)

The film was loosened from the obtained rolls and cut into 10-point size, 4 cm x 4 cm, at regular intervals in the width direction, and the obtained film was stored in a thermostatic chamber at 50 ° C for 2000 hours. The film after storage was humidity-conditioned at 23 deg. C and 55% RH, and haze was measured in the same manner as described above, and the average value of ten points was determined. Then, the haze value (average value) before storage and the haze value (average value) after storage were applied to the following equations to calculate the change ratio of haze.

Change ratio of haze = (haze after storage - haze before storage) / (haze before storage) x 100 (%)

&Amp; cir &amp;: Change ratio of haze is less than 3%

○: Change ratio of haze is 3% or more and less than 5%

?: Change ratio of haze is 5% or more and less than 15%

X: Change ratio of haze is 15% or more

A polarizing plate was produced by the following method using the film obtained from the roll thus prepared, and the yield of the polarizing plate was evaluated.

(Yield of polarizing plate)

1) Production of polarizer

A polyvinyl alcohol film having a thickness of 30 占 퐉 was swelled in water at 35 占 폚. The obtained film was immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds and immersed in an aqueous solution at 45 캜 containing 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water. The resulting film was uniaxially stretched under the conditions of a stretching temperature of 55 캜 and a draw ratio of 3. The uniaxially stretched film was washed with water and then dried to obtain a polarizer having a thickness of 5 탆.

2) Preparation of active energy ray-curable adhesive liquid

The following components were mixed and defoamed to prepare a radical polymerization type active energy ray curable adhesive liquid.

(Composition of active energy ray curable adhesive liquid)

Radical Polymerizable Compound 1: Hydroxyethyl acrylamide (HEAA, Tg of homopolymer 123 deg. C, manufactured by Sojun Kogyo Co., Ltd.): 39.1 mass%

Radopolymerizable compound 2: 19.0% by mass of tripropylene glycol diacrylate (Aronix M-220, Tg of the homopolymer: 69 ° C, manufactured by Toagosei Co., Ltd.)

Radical Polymerizable Compound 3: acryloylmorpholine (ACMO, Tg of homopolymer: 150 占 폚, manufactured by Sojun Kogyo Co., Ltd.): 39.1 mass%

Radical polymerization initiator 1: 1.4 mass% Diethyl thioxanthone (KAYACURE DETX-S, manufactured by Nippon Kayaku Co., Ltd.)

Radical polymerization initiator 2: 1.4 mass% of 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (IRGACURE 907,

3) Production of Polarizer

Two films (films obtained from rolls of the same number) obtained from the rolls manufactured under the same manufacturing conditions were prepared, and the surfaces were subjected to corona discharge treatment. The conditions of the corona discharge treatment were a corona output power of 2.0 kW and a line speed of 18 m / min. Subsequently, the prepared active energy ray-curable adhesive liquid was coated and applied on the corona discharge treated surface of the film by a bar coater so that the film thickness after curing became about 3 mu m, to form an active energy ray curable adhesive layer.

Subsequently, the prepared polarizer was sandwiched between the two films to obtain a laminate of a film / active energy ray curable adhesive layer / polarizer / active energy ray curable adhesive layer / film.

Ultraviolet light (gallium-encapsulated metal halide lamp) was irradiated onto one side of this laminate using an ultraviolet irradiation device (Light HAMMER 10, Bulb: V bulb, peak illuminance: 1600 mW / cm 2) equipped with a belt conveyor , And a total irradiation dose of 1000 / mJ / cm 2 (wavelength: 380 to 440 nm) to cure the active energy ray curable adhesive layer to obtain a polarizing plate.

4) Evaluation

The yield of the obtained polarizing plate was evaluated by the following method.

The surface of the polarizing plate was visually observed, and the transmittance due to the planar failure and the haze was evaluated. The transmittance due to the haze of the polarizing plate was confirmed by sensory evaluation when the polarizing plate was placed on a white sheet or the like and whether there was any residual scratches. In addition, the flatness failure and the permeability caused by the haze are all good, which is called good. The ratio of good and defective products when 50 sheets of polarizing plates were prepared was calculated.

◎: 95% or more of good polarizer

○: 80% or more and less than 95% of good polarizer

?: 60% or more and less than 80% of good polarizer

X: less than 60% of good polarizer

The evaluation results of Examples 1 to 12 and Comparative Examples 1 to 7 are shown in Table 6; The evaluation results of Examples 13 to 25 and Comparative Examples 8 to 9 are shown in Table 7.

As shown in Tables 6 and 7, in the rolls of Examples 1 to 25, deformation of the rolls is suppressed and the haze is also low.

On the other hand, in the roll of Comparative Example 1, deformation of the roll occurred and the roll shape was bad. It is considered that this is because the winding diameter is increased at both end portions in the width direction of the roll body because of the non-vibration winding method (straight winding), and wrinkles are generated in the entire roll body. On the other hand, in the rolls of Comparative Examples 3 and 4, deformation of the roll was suppressed, but the haze was increased. This is presumably because the slidability of the film is low, and the films are mutually crossed to each other and residual scratches are formed on the surface of the film. It is considered that the film of Comparative Example 5 is extremely thin, and thus the deformation of the roll can not be sufficiently suppressed. The film of Comparative Example 6 could not suppress deformation of the roll. This is presumably because the content of the compound represented by the formula (1) is excessively large, so that the film tends to slide excessively and winding displacement occurs. In addition, an increase in haze due to the shedding (precipitation) of the additive caused by a large amount of additive added was observed.

It can be seen from the contrast of Examples 1, 13 and 14 and Comparative Example 8 that the haze of the film can be reduced by setting the number of carbon atoms of the alkyl group of R ₁ and R _{2 in} the formula (1) to 8 or more. From the contrast between Example 13 and Example 15, it can be seen that the haze of the film can be reduced by making the alkyl group of R ₁ and R ₂ of the formula (1) straight chain. Further, from the comparison between Example 24 and Comparative Example 9, it can be seen that the L of Formula (1) contains a carbonyl group, the compatibility with the cellulose ester increases and the internal haze can be reduced. From the comparison between Example 16 and Example 23, it can be seen that the haze of the film can be reduced by using an alkyl group as both of R ₁ and R _{2 in} the formula (1) .

From the comparison between the comparative example 2 and the comparative example 7, the film obtained from the roll of the comparative example 2 including the aliphatic polyester compound is superior to the film obtained from the roll of the comparative example 7 containing no aliphatic polyester compound, The deformation of the roll is remarkable when straight winding is carried out. From this point of view, it is suggested that by applying the present invention, even a film containing an aliphatic polyester compound can well suppress the deformation of the roll.

An optical film and its roll were obtained in the same manner as in Comparative Example 1 except that the thickness of the optical film was changed to 50 탆. The shape of the obtained roll was evaluated in the same manner as described above, and the result was &quot;? &Quot;, and deformation of the roll did hardly occur. In view of this, it is suggested that &quot; deformation of the roll body &quot;, which is a problem of the present invention, occurs remarkably when the film thickness is thinner than 50 탆.

This application claims priority based on Japanese Patent Application No. 2014-047539 filed on March 11, 2014. The contents of the present specification and drawings are all incorporated herein by reference.

&Lt; Industrial applicability >

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a roll of an optical film in which deformation of a roll is suppressed and increase in haze is suppressed.

10: Roll body
11: Winding core
13: Optical film
13A: Embossing section
20: winding device
21: Vibration control device
23: guide roller
25: touch roller
100: Small liquid crystal display
110: liquid crystal cell
130: first polarizing plate
131: first polarizer
133, 135, 153, 155: protective film
150: second polarizer plate
151: second polarizer
170: Backlight
190: Cover glass
210: touch panel section
230: Rechargeable battery

Claims (13)

A roll of an optical film obtained by winding an optical film having a thickness of 15 to 45 占 퐉 and having embossed portions at both ends in the width direction,
Wherein the optical film comprises a cellulose ester and 0.05 to 5 parts by mass of a compound represented by the following formula (1) based on 100 parts by mass of the cellulose ester,

(In the formula (1)
L is a combination of at least one member selected from the group consisting of ester bond, amide bond, carbonyl group, ester bond, amide bond or carbonyl group and alkylene group, nitrogen atom, oxygen atom, sulfur atom, zinc atom, calcium atom and magnesium atom A bivalent group;
R ₁ represents an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms;
R ₂ represents a hydrogen atom, an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms)
And a side surface shape of both end portions in the axial direction of the roll body is wavy. The compound according to claim 1, wherein L in the formula (1)
-C (= O) -O-, -C (= O) NH-,
_{-C (= O) -OR 3 -OC} (= O) -, -C (= O) -NH-R 3 -NH-C (= O) - (R 3 is an alkylene group having 1 to 5 carbon atoms),
-C (= O) -OMOC (= O) - (M is a zinc atom, a calcium atom or a magnesium atom)
_{-C (= O) -R 4 -OR} 4 -C (= O) -, -C (= O) -R 4 -SR 4 -C (= O) -, -C (= O) -R 4 - NH-R ₄ -C (= O) - (R ₄ is an alkylene group having 1 to 5 carbon atoms) and
Is a group selected from the group consisting of -C (= O) -R ₅ -C (= O) - (R ₅ is an alkylene group having 1 to 5 carbon atoms). The compound according to Claim 1, wherein R ₁ and R ₂ in Formula (1) are each independently a linear alkyl group having 8 to 26 carbon atoms or a straight chain alkenyl group having 8 to 26 carbon atoms , A roll body of an optical film. The roll of an optical film according to claim 1, wherein L in the formula (1) comprises a sulfur atom. The optical film roll according to claim 1, wherein the optical film further comprises an aliphatic polyester compound obtained by polycondensing an aliphatic diol and an aliphatic dicarboxylic acid. The optical film according to claim 1, wherein the retardation in the in-plane direction of the optical film defined by the following formula (I) and measured at a measurement wavelength of 590 nm is defined as Ro (590) Satisfies | Ro (590) |? 5 nm and | Rth (590) |? 5 nm when the retardation in the thickness direction measured at a measurement wavelength of 590 nm is Rth (590).
(I) Ro = (nx-ny) x t (nm)
Rth = {(nx + ny) / 2-nz} x t (nm)
(In the formulas (I) and (II)
nx represents a refractive index in the slow axis direction x at which the refractive index becomes the maximum in the in-plane direction of the film; ny represents a refractive index in an in-plane direction of the film in a direction orthogonal to the slow axis direction x; nz represents the refractive index in the thickness direction z of the film; t (nm) denotes the thickness of the film) A long shaped optical film having a thickness of 15 to 45 탆 and containing a compound represented by the following formula (1) and having an embossed portion at both ends in the width direction is prepared in an amount of 0.05 to 5 parts by mass with respect to 100 parts by mass of the cellulose ester ;

(In the formula (1)
L is a combination of at least one member selected from the group consisting of ester bond, amide bond, carbonyl group, ester bond, amide bond or carbonyl group and alkylene group, nitrogen atom, oxygen atom, sulfur atom, zinc atom, calcium atom and magnesium atom A bivalent group;
R ₁ represents an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms;
R ₂ represents a hydrogen atom, an alkyl group having 8 to 26 carbon atoms or an alkenyl group having 8 to 26 carbon atoms)
And winding the optical film on the winding core in a roll form,
Wherein the step of winding includes a step of winding at least one of the optical film and the winding core on the winding core while periodically vibrating at least one of the optical film and the winding core in the width direction of the optical film Gt; A polarizing plate comprising an optical film obtained from the roll of claim 1. A liquid crystal display device comprising an optical film obtained from the roll of claim 1. The liquid crystal display device according to claim 9, comprising a first polarizing plate, a liquid crystal cell, a second polarizing plate, and a backlight in this order,
Wherein the first polarizer comprises a first polarizer, a protective film (F1) disposed on a surface of the first polarizer opposite to the liquid crystal cell, and a protective film disposed on a surface of the first polarizer facing the liquid crystal cell F2)
The second polarizer includes a second polarizer, a protective film (F3) disposed on the side of the liquid crystal cell side of the second polarizer, and a protective film (F3) disposed on a surface of the second polarizer opposite to the liquid crystal cell F4)
And at least one of the protective films (F2 and F3) comprises the optical film. The liquid crystal display of claim 10, wherein the liquid crystal cell is a liquid crystal cell of an IPS mode or an FFS mode. The liquid crystal display device according to claim 9, wherein a length of the display area in the diagonal direction is 10 inches or less. 13. The liquid crystal display according to claim 12, further comprising a rechargeable battery.

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