KR20130141380A - Optical film, retardation film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

The present invention provides optical films in which the outer surface of the rolls are outstanding and have desired retardation or the desired retardation of dependence on humidity or has small changes in sizes so that the optical films can be used for polarizing plates or display devices. Therefore the optical films of the present invention prevents the optical films from being recessed and embossed and provides good quality polarizing plates that has excellent adhesion. In addition, when viewed at a front side and inclinedly, it provides a liquid crystal panel or device that prevents uneven light from being generated on the surface. Therefore, the optical film has at least one or more additives with cellulose ester. The total amount of the additives (Unit : Ct, the mass to the cellulose ester inside the additives) and the film thickness (Unit: d, μm) satisfy the equation of Ct/d >= 0.375. The optical film has one or more linear concave and/or convex images having a height of 3 to 30 nm within 1000 mm and does not have or has one or less linear concave and/or convex image having a height of 30 to 300 nm within 1000 mm.

Description

Optical film, retardation film, polarizer and liquid crystal display device {OPTICAL FILM, RETARDATION FILM, POLARIZING PLATE, AND LIQUID CRYSTAL DISPLAY DEVICE}

This invention relates to the optical film which is excellent in adhesiveness with a polarizing film, and contains the cellulose ester which can be bonded directly to a polarizing film, and also the retardation film using this optical film, and this optical film It relates to a polarizing plate, a liquid crystal panel, and a liquid crystal display device which are excellent in used surface shape and have high reliability.

The polymer film represented by a cellulose ester, polyester, a polycarbonate, a cycloolefin polymer vinyl polymer, a polyimide, etc. is used for a silver halide photosensitive material, a retardation film, a polarizing plate, and an image display apparatus. Since these polymers can produce more excellent films from the point of planarity and uniformity, they are widely employed as films for optical applications.

Among these, the optical film containing the cellulose acylate which has a suitable water vapor transmission rate can be directly bonded online with the polarizing film which consists of the most common polyvinyl alcohol (PVA) / iodine. Therefore, the optical film containing cellulose acylate (especially the optical film containing cellulose acetate) is widely employ | adopted as a protective film of a polarizing plate.

When such a film is used for optical applications such as a retardation film, a support of a retardation film, a protective film of a polarizing plate, and a liquid crystal display device, control of the optical anisotropy determines the performance (eg, visibility) of the display device. It is a very important factor. With the recent wide viewing angle demands of liquid crystal display devices, the compensation of retardation is required to be improved, and the retardation value (Re; in the in-plane direction of the retardation film disposed between the polarizing film and the liquid crystal cell is simply described below. It may be called "Re") and the retardation value (Rth; may just be called "Rth" hereafter) of the film thickness direction suitably. For example, in the liquid crystal display device of the IPS mode widely used for liquid crystal television use, it is required to reduce both Re and Rth. For example, patent document 1 has polyester which both ends are hydroxyl groups with respect to cellulose acylate. The technique which contains 5 mass% or more of diols is disclosed. Moreover, in the VA mode liquid crystal display device, it is required to raise both Re and Rth, and in order to adjust to appropriate Re and Rth, adjustment of the material which comprises a film, adjustment of the film forming method, and extending | stretching of a film are also required. The technique which performs an operation is disclosed (for example, refer patent documents 2-5).

On the other hand, as the liquid crystal display device has been slimmer, it has been found that circular light irregularities occur when the display surface is observed from the front under specific conditions. Although the mechanism of occurrence of this light nonuniformity is still unclear, as one cause, the backlight member and the liquid crystal panel (particularly, the backlight side polarizer) partially contact each other, and the luminance or color taste at the portion that did not contact the contacted portion. ) Changes. Therefore, Patent Document 6 discloses a method of preventing contact with the backlight member by forming irregularities on the surface of the backlight side protective film of the backlight side polarizing plate to suppress the occurrence of light nonuniformity.

Japanese Unexamined Patent Publication No. 2009-098674 European Patent 0911656 Japanese Patent Laid-Open No. 5-257014 Japanese Laid-Open Patent Publication 2005-138358 Japanese Unexamined Patent Publication No. 2001-100039 Japanese Unexamined Patent Publication No. 2009-169393

However, when using a polyethylene terephthalate film as a protective film of a polarizing plate like patent document 6, there exists a difficulty in polarizing plate workability, causing the fall of the production speed of a polarizing plate, or in the liquid crystal panel using such a polarizing plate. It has become clear that warpage occurs or light irregularities occur on the outer periphery of the display surface under specific conditions.

Then, in order to solve such a subject of the prior art, the present inventors manufacture the optical film which is excellent in polarizing plate workability, and does not generate circular light nonuniformity or light nonuniformity of the outer periphery on the display surface of a liquid crystal display device, and a polarizing plate. The study was advanced for the purpose of the present invention. And as an optical film containing a cellulose ester, elasticity modulus, photoelasticity, moisture absorption rate, and humidity of Rth are controlled by suitably controlling (Ct / d ≧ 0.375) the relationship between the total content of the one or two or more additives in the optical film and the film thickness. By using the optical film which controlled dependency, it discovered that these subjects could be solved.

By the way, when such a film is manufactured continuously, when the film | membrane (stripe-shaped) unevenness | corrugation arises in a film, and the transmission and observation of the polarizing plate using this film, the new subject that the contrast derived from this structure may be visualized became clear. .

An object of the present invention is to provide an optical film that is excellent in the appearance of a roll, has a desired retardation and a humidity dependency of a desired retardation, and is excellent in planar shape and can be used for a polarizing plate or a liquid crystal display device. Moreover, generation | occurrence | production of the stripe-shaped unevenness | corrugation using such an optical film is suppressed, and it is providing the polarizing plate excellent in adhesiveness. Moreover, it is providing the liquid crystal panel by which the light nonuniformity generate | occur | produced in the display surface at the time of observing front and obliquely using the retardation film and polarizing plate manufactured using the said optical film, and a liquid crystal display device.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, it was related with the problem of the said linear unevenness | corrugation and discovered that what has a specific uneven | corrugated shape among linear unevenness is recognized also in the state of a polarizing plate. In addition, the formation of the specific linear irregularities causes the dope discharge port to rapidly become contaminated when the film satisfying the relationship between the total content of one or two or more additives in the optical film and the film thickness (Ct / d? 0.375) is soft. It is estimated that this is caused by a shape such as a scratch mark on the discharged dope surface, and is difficult to level because the drying speed of the web is increased, and it is estimated that it is facilitated by unevenness.

The dope discharge port is contaminated because the discharge pressure from the die decreases when the film satisfying the relationship between the total content of one or two or more kinds of additives in the optical film and the film thickness (Ct / d? 0.375) is lowered. It was estimated that the resultant dope was caused by a disturbance such as mechanical vibration or wind unevenness, which made it easy to vibrate, and thus increased probability of being attached to the discharge port. In addition, the faster the drying rate, the lower the glass transition temperature of the web (film) accompanying the increase in the total content (that is, the molecular mobility in the web (film) increases, and the diffusion rate of the solvent also increases) and the film thickness decreases. It was assumed that this resulted from an increase in the solvent diffusion distance accompanying the process.

Therefore, in order to eliminate this contamination, it is considered that the response to increase the discharge pressure is effective, and by combining the following appropriately, it is found that a film which solves the problems of light irregularity and linear irregularities can be produced to complete the present invention. Reached.

That is, this invention can be achieved by the following means.

[One]

As an optical film containing 1 or 2 or more types of additives, and a cellulose ester,

The total content (Ct; unit: mass% of the cellulose ester) and the film thickness (d; unit µm) of the additive satisfy the relationship of Ct / d ≧ 0.375,

Has one or more linear concave and / or convex shapes having a height of 3 to 30 nm in any 1000 mm section,

An optical film having a linear concave and / or convex shape of more than 30 nm in height and 300 nm or less in any 1000 mm section, or having one or less.

[2]

The optical film as described in [1] in which the said optical film contains a thickener further.

[3]

The optical film as described in [1] or [2] whose viscosity average degree of polymerization of the said cellulose ester is 180-550.

[4]

The optical film in any one of [1]-[3] whose acyl substitution degree with respect to the hydroxyl group of the said cellulose ester is 2.60-3.00.

[5]

The laminated body which has a film laminated part formed by winding or bending of the optical film in any one of [1]-[4] of 1 sheet, or by overlapping two or more said optical films.

[6]

Retardation film containing the optical film as described in any one of [1]-[4], or the laminated body as described in [5] at least.

[7]

The polarizing plate containing at least the optical film as described in any one of [1]-[4], the laminated body as described in [5], or the retardation film as described in [6].

[8]

The image display apparatus containing at least the optical film as described in any one of [1]-[4], the laminated body as described in [5], the retardation film as described in [6], or the polarizing plate as described in [7].

[9]

The image display device according to [8], wherein the image display device is a liquid crystal display device in an IPS mode or a VA mode.

It is preferable that this invention is further the following structures.

[10]

The optical film as described in any one of [1]-[4] whose said additive is a compound which has a repeating unit.

[11]

The optical film as described in [10] whose compound which has the said repeating unit is a condensate of polyhydric alcohol and polybasic acid.

[12]

The optical film as described in [11] whose said condensate of polyhydric alcohol and polybasic acid is a condensate of glycol of 2 to 12 carbon atoms and dibasic acid of 4 to 12 carbon atoms.

[13]

The optical film as described in any one of [1]-[4] and [10]-[12] containing the compound represented by following General formula (1) or (2).

In general formula (1)

[Formula 1]

(In general formula (1), Ra is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted heterocyclic group, or a substituted or unsubstituted aryl group. X ¹ , X ² , X ³ and X ⁴ each independently represent a single bond or a divalent linking group R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group , Substituted or unsubstituted alkenyl group, substituted or unsubstituted alkynyl group, substituted or unsubstituted aryl group, substituted or unsubstituted acyl group, or substituted or unsubstituted heterocyclic group)

In general formula (2)

(2)

(In General Formula (2), Rb and Rc are each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted heterocyclic group, or a substituted or Unsubstituted aryl X ⁵ and X ⁶ each independently represent a single bond or a divalent linking group R ⁵ and R ⁶ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkene Or a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted acyl group, or a substituted or unsubstituted heterocyclic group)

[14]

The optical film in any one of [1]-[4] and [10]-[13] whose thickness is 5-120 micrometers.

[15]

1 or 2 or more types of additives and a cellulose ester,

As a manufacturing method of the optical film in which the total content (Ct; unit: mass% with respect to the said cellulose ester) of this additive, and film thickness (d; unit micrometer) satisfy | fill a relationship of Ct / d≥0.375,

And a step of extruding a fluid containing at least the additive and the cellulose ester from the die, and the liquid supply pressure to the die is 0.5 MPa or more.

[16]

The manufacturing method of the optical film as described in [15] whose clearance of the said die to discharge is 0.2-1.5 mm.

The optical film containing the cellulose ester of this invention is excellent in the external appearance of a roll, has a desired retardation, and the humidity dependence of a desired retardation, and can be used for a polarizing plate and a liquid crystal display device as an optical film excellent in planar shape. Generation | occurrence | production of the stripe-shaped unevenness | corrugation using such an optical film can be suppressed, and the polarizing plate excellent in adhesiveness can be provided. Moreover, the liquid crystal panel using the retardation film and polarizing plate which are manufactured using the optical film of this invention, and the liquid crystal display device have improved the light nonuniformity of the display surface at the time of oblique observation, and show the outstanding reliability.

Hereinafter, the present invention will be described in detail. In addition, in this specification, when a numerical value shows a physical property value, a characteristic value, etc., description of "(numerical value 1)-(numerical value 2)" and "(numerical value 1)-(numerical value 2)" refers to "(numerical value 1). ) Or more (value 2) or less ”.

The optical film of this invention is a film containing an additive and a cellulose ester at least, and contains 1 or 2 or more types of additives with the quantity which satisfy | fills the relationship of Ct / d≥0.375 with respect to a cellulose ester.

 As the additive, an additive (for example, KIPO 2001-1745) commonly used for cellulose ester can be used, and a compound having a repeating unit as described later can be used for bleed-out suppression or film production process. It is preferable from a viewpoint of volatilization suppression.

In this invention, the said additive is a component different from the high molecular compound different from the said cellulose ester and the cellulose ester mentioned later, and when calculating the total content (Ct) of 1 or 2 or more types of additives, a cellulose ester and later mentioned A high molecular compound different from a cellulose ester shall not be included in an "additive."

The optical film of this invention can improve the light nonuniformity of a liquid crystal display device by containing an additive (preferably the compound which has a repeating unit) with respect to a cellulose ester.

In addition, the relationship between the total content of the one or two or more additives (preferably a compound having a repeating unit) and the film thickness satisfies Ct / d ≧ 0.563, and more preferably Ct / d ≧ 0.750. Do.

Although there is no restriction | limiting in particular as an upper limit of Ct / d, It is preferable that Ct / d <= 3.0, It is more preferable that Ct / d <= 2.0, It is still more preferable that Ct / d <= 1.5.

In this invention, content (mass%) of the additive with respect to a cellulose ester shall be represented by "phr."

20-200 phr is preferable, as for the total content (Ct) of 1 or 2 or more types of additives (preferably the compound which has a repeating unit), 30-180 phr is more preferable, 45-150 phr is more preferable. However, in a range satisfying Ct / d ≧ 0.375, the content of the additive is preferably 2 to 100 phr, more preferably 5 to 50 phr, and even more preferably 6 to 30 phr in some cases. The latter preferable aspect can be preferably applied from the viewpoint of light nonuniformity improvement, especially when the film thickness is thin. The total content and film thickness satisfying such conditions are preferable because they can improve the light unevenness, and if it is 200 phr or less, the bleed out from the film is easily suppressed and preferable. In the case of a film having a thin film thickness, the upper limit of the total content is set low because of the tendency of bleeding out from the film to be promoted. On the other hand, from the viewpoint of increasing the viscosity of the dope, increasing the discharge pressure from the die described later to suppress linear irregularities, the total content is preferably small, and is preferably set appropriately while checking these balances.

In the present invention, the light unevenness is improved by including an additive that satisfies the condition of Ct / d ≥ 0.375. However, if the total content (Ct) is increased or the film thickness (d) is decreased, dope discharge from the die is unstable. It turned out that drying speed at the time of film-forming or film forming becomes high. In addition, since the problem that the linear unevenness | corrugation visually recognized also generate | occur | produces also in a polarizing plate state by the continuous manufacture on such conditions, by measuring these in accordance with this invention, the film without a specific linear unevenness | corrugation and the linear uneven | corrugated trace | derived from a film are not found. It turned out that a polarizing plate is obtained.

In addition, when including 2 or more types of additives, in the optical film of this invention, the total content of the 2 or more types of additives should just be included in the said range. In addition, when the optical film of this invention contains polymers other than a cellulose ester (for example, a polymer blend), polymers other than this cellulose ester shall not be included in an additive.

[Compound having repeating unit]

It is preferable that the optical film of this invention contains the compound which has a repeating unit.

It is preferable that it is 600-50000, as for the number average molecular weight (Mn) of the compound which has a repeating unit in this invention, it is more preferable that it is 1000-10000, and 1000-5000 are still more preferable. If the number average molecular weight of the compound which has a repeating unit is 600 or more, volatility will become low, and the film failure and process contamination by volatilization under the high temperature conditions at the time of forming or extending the optical film of this invention will not produce easily, and the molecular weight By raising, it is possible to suppress the change in retardation when maintained in a moist heat environment. Moreover, if it is 50000 or less, compatibility with a cellulose ester can be ensured, the humidity dependence of retardation considered to originate from a cellulose ester molecule can be reduced effectively, and bleed-out can be suppressed. However, the compound which has a repeating unit in this invention is not limited to what consists only of the compound which has such a repeating unit part, and may be a mixture with the compound which does not have a repeating unit.

The number average molecular weight of the compound which has a repeating unit in this invention can be measured and evaluated by gel permeation chromatography.

Moreover, the compound which has a repeating unit of this invention may be a liquid, or a solid may be sufficient as the environment temperature or humidity (generally room temperature conditions, so-called 25 degreeC, relative humidity 60%) to be used. It is preferable that the color tone is better as the color tone is smaller, and particularly, it is colorless. It is preferable that it is thermally stable at a higher temperature, and the decomposition initiation temperature is 150 ° C or more, and preferably 200 ° C or more.

Hereinafter, although the compound which has a repeating unit used for this invention is demonstrated in detail, giving the specific example, the compound which has a repeating unit which can be used by this invention is not limited to these.

(Types of Compounds Having Recurring Units)

Although it does not specifically limit as a compound which has a repeating unit which can be used for the optical film of this invention, A condensate or an addition product is mentioned, As a condensate, the condensate of a polyhydric alcohol and a polybasic acid, and a polyhydric ether alcohol and a polybasic acid Condensates, condensates of polyhydric alcohols and polybasic acids, and condensates of isocyanate compounds are preferable, and examples of the adduct include adducts of acrylic acid esters and adducts of methacrylic acid esters. Moreover, the number average molecular weight of at least 1 sort (s) chosen from a polyether type compound, a polyurethane type compound, a polyether polyurethane type compound, a polyamide type compound, a polysulfone type compound, a polysulfonamide type compound, the other high molecular compound mentioned later The compound which is 600 or more can also be used.

At least one of them is preferably a condensate of a polyhydric alcohol and a polybasic acid, a condensate of a polyhydric ether alcohol and a polybasic acid, an adduct of an acrylate ester, and an adduct of a methacrylic acid ester, and a polyhydric product of the polyhydric alcohol and a polybasic acid. It is more preferable that it is a condensate of ether alcohol and polybasic acid, and it is still more preferable that it is a condensate of polyhydric alcohol and polybasic acid.

Below, the compound which has a repeating unit used preferably by this invention is described for each kind.

 (Condensates of polyhydric alcohols and polybasic acids)

First, the condensate of a polyhydric alcohol and a polybasic acid used in the present invention will be described. Although it does not specifically limit as a preferable condensate of polyhydric alcohol and polybasic acid, It is obtained by reaction of dibasic acid and glycol, Although both ends of a reactant may be a reactant state, Furthermore, monocarboxylic acid and monoalcohol are made to react, When the so-called terminal sealing is performed, the retardation change at the time of holding in a wet heat environment can be suppressed, and it is preferable. In such a condensate, it is preferable that a hydroxyl value falls, and that a hydroxyl value is less than 40 mgKOH / g, It is more preferable that it is 20 mgKOH / g or less, and 10 mg compared with the condensate which the terminal is unsealed. It is more preferable that it is KOH / g or less.

In the condensate of a polyhydric alcohol and a polybasic acid used in the present invention, the polyhydric alcohol preferably contains a polyhydric alcohol having at least 3 carbon atoms or more from the viewpoint of suppressing contamination of the flexible support.

It is preferable to synthesize | combine the condensate of the polyhydric alcohol and polybasic acid used by this invention with the C2-C12 glycol and C4-C12 dibasic acid.

As a dibasic acid used for the condensate of the polyhydric alcohol and polybasic acid of this invention, it is a C3-C12 aliphatic dicarboxylic acid residue or an alicyclic dicarboxylic acid residue, or a C8-C12 aromatic dicarboxylic acid residue. It is preferable. And in order to raise the grade of the bleed out with heat processing, it is more preferable to contain an aliphatic polybasic acid of at least 4 carbon atoms, and / or to contain an aromatic polybasic acid. Moreover, as glycol, it is preferable that they are a C2-C12 aliphatic or alicyclic glycol residue and a C6-C12 aromatic glycol residue. These can be suitably selected and used according to a desired retardation, and may contain only one type, and may contain two or more types. For example, when it is desired to produce a film with reduced retardation, it is preferable to select aliphatic or alicyclic dicarboxylic acid residues or phthalic acid residues, and aliphatic or alicyclic glycol residues. Moreover, when it is desired to manufacture the film which raised the retardation, it is preferable to contain an aromatic dicarboxylic acid residue and / or an aromatic glycol residue.

Hereinafter, the dibasic acid and glycol which can be used suitably for the synthesis | combination of the condensate of polyhydric alcohol and polybasic acid in this invention are demonstrated.

As the dibasic acid, both aliphatic dicarboxylic acid and aromatic dicarboxylic acid can be used.

As aliphatic dicarboxylic acid, for example, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, suberic acid, azelaic acid, cyclohexanedicarboxylic acid, sebacic acid, dode And candicarboxylic acid. Especially, it is preferable to contain malonic acid, succinic acid, and adipic acid from a viewpoint of compatibility improvement.

Examples of the aromatic dicarboxylic acid include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalene dicarboxylic acid and 1,4-naphthalene dicarboxylic acid. Especially, phthalic acid and terephthalic acid are preferable and terephthalic acid is especially preferable.

It is preferable that carbon number of the dibasic acid used for this invention is 3-12, It is more preferable that it is 4-8, It is preferable that it is 4-6. In this invention, you may use the mixture of 2 or more types of dibasic acids, In this case, it is preferable that the average carbon number of 2 or more types of dibasic acids becomes the said range. If carbon number of a dibasic acid is the said range, in addition to the improvement of a light nonuniformity, since it is excellent in compatibility with a cellulose ester, and a bleed out does not generate | occur | produce well at the time of film forming of a optical film, and heat extension, it is preferable.

It is also preferable to use an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid in combination. Specifically, the combination of adipic acid and phthalic acid, the combination of adipic acid and terephthalic acid, the combination of succinic acid and phthalic acid, the combination of succinic acid and terephthalic acid, and the combination of succinic acid and phthalic acid, and the combination of succinic acid and terephthalic acid are more preferable. When using an aliphatic dicarboxylic acid and aromatic dicarboxylic acid together, the ratio (molar ratio) of both is not specifically limited, 95: 5-40: 60 are preferable and 55: 45-45: 55 is more preferable.

Aliphatic diols and aromatic diols are mentioned as glycol (diol), and aliphatic diol is preferable.

Examples of the aliphatic diols include alkyldiols and alicyclic diols, and examples thereof include ethylene glycol (ethanediol), 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1, 3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentylglycol), 2,2- Diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1 , 5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1 , 3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol and the like.

Preferred aliphatic diols are at least one species of ethylene glycol, 1,2-propanediol, and 1,3-propanediol, and particularly preferably at least one species of ethylene glycol and 1,2-propanediol. When using 2 types, it is preferable to use ethylene glycol and 1, 2- propanediol.

It is preferable that carbon number of glycol is 2-10, It is more preferable that it is 2-6, It is especially preferable that it is 2-4. When using 2 or more types of glycols, it is preferable that the 2 or more types of average carbon numbers become the said range. If the carbon number of glycol is the said range, since it is excellent in compatibility with a cellulose ester in addition to the improvement of a light nonuniformity, and bleed-out does not generate | occur | produce well also at the time of film forming and heat extending of a film, it is preferable.

Moreover, it is preferable to protect the both ends of the condensate of the polyhydric alcohol and polybasic acid of this invention with a monoalcohol residue or a monocarboxylic acid residue. In this case, the monohydric alcohol residue is preferably a substituted or unsubstituted monohydric alcohol residue having 1 to 30 carbon atoms, and may be selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, isopentanol, There may be mentioned alcohols such as cyclohexyl alcohol, cyclohexyl alcohol, octanol, isooctanol, 2-ethylhexyl alcohol, nonyl alcohol, isononyl alcohol, tert-nonyl alcohol, decanol, dodecanol, dodecahexanol, Aliphatic alcohols such as methanol and ethanol, substituted alcohols such as benzyl alcohol and 3-phenylpropanol, and the like.

In the case of encapsulating with a monocarboxylic acid residue, the monocarboxylic acid used as the monocarboxylic acid residue is preferably a substituted or unsubstituted monocarboxylic acid having 1 to 30 carbon atoms. These may be aliphatic monocarboxylic acids or aromatic carboxylic acids. Examples of the aromatic aliphatic monocarboxylic acid include aliphatic monocarboxylic acids such as acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid and oleic acid. Benzoic acid, p-tert-butylbenzoic acid, orthotoluenic acid, meta-toluic acid, paratoluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid and acetoxybenzoic acid, Can be used as the above mixture.

At this time, when the carbon number of the monocarboxylic acid residue at both ends is 3 or less, volatility falls, and the weight loss by heating the condensate of the polyhydric alcohol and polybasic acid does not become large, and the occurrence of process contamination and the occurrence of surface failure are reduced. You can. From such viewpoints, aliphatic monocarboxylic acids are preferable as monocarboxylic acids to be used for encapsulation. It is more preferable that monocarboxylic acid is a C2-C22 aliphatic monocarboxylic acid, It is still more preferable that it is a C2-C3 aliphatic monocarboxylic acid, It is especially preferable that it is a C2 aliphatic monocarboxylic acid residue. For example, acetic acid, propionic acid, butanoic acid, benzoic acid and derivatives thereof are preferable, acetic acid or propionic acid is more preferable, and acetic acid (whose terminal is acetyl group) is most preferable. The monocarboxylic acid used for sealing may mix 2 or more types.

Moreover, when the both ends of the condensate of polyhydric alcohol and a polybasic acid are unsealed, it is preferable that the condensate is polyester polyol.

As mentioned above, as a preferable condensate of polyhydric alcohol and polybasic acid, a poly (ethylene glycol / adipic acid) ester, a poly (propylene glycol / adipic acid) ester, a poly (1, 3- butanediol / adipic acid) ester, Poly (propylene glycol / sebacic acid) ester, poly (1, 3- butanediol / sebacic acid) ester, poly (1, 6- hexanediol / adipic acid) ester, poly (propylene glycol / phthalic acid) ester, poly (1 2-butanediol / phthalic acid) ester, poly (propylene glycol / terephthalic acid) ester, poly (propylene glycol / 1,5-naphthalene-dicarboxylic acid) ester, and poly (propylene glycol / terephthalic acid) ester 2-ethyl-hexyl alcohol ester, the acetylated poly (butanediol / adipic acid) ester, etc. are mentioned at the both ends of ethyl-hexyl alcohol ester / poly (propylene glycol, adipic acid) ester.

Synthesis of such condensates of polyhydric alcohols and polybasic acids is a thermal melt condensation method by a (poly) esterification reaction or transesterification reaction of the dibasic acids or their alkyl esters and glycols by conventional methods, or these It can be synthesize | combined easily by any method of the interfacial condensation method of the acid chloride of an acid, and glycols. Condensates of polyhydric alcohols and polybasic acids are described in detail in Korai Murai, "Theory and Application of Plasticizers" (Showa, Saiwai, First Edition, March 1, 1973). Japanese Laid-Open Patent Publication Nos. 05-155809, 05-155810, 5-197073, 2006-259494, and 07-330670 , Japanese Unexamined Patent Application Publication No. 2006-342227, Japanese Unexamined Patent Publication No. 2007-003679, and the like can be used.

Moreover, the compound (oligomer) whose molecular weight is the said preferable range among what is sold from each company as a commodity can be used as an additive. Specifically, ADEKA Co., Ltd. can be used as a condensate of a polyhydric alcohol and a polybasic acid, such as the adecaser described in DIARY 2007, pages 55 to 27, which are various as adecaser P series and adecaser PN series. Various products of polylite described in page 25 of Dainippon Ink and Chemicals Co., Ltd. "2007 List of Polymer Related Products" and pages 2 to 5 of Dainippon Ink and Chemicals Co., Ltd. Various kinds of polysizers can be used. Further, it can be obtained as Plasthall P series manufactured by CP HALL, USA. Benzoyl functionalized polyethers are commercially available from Belsicol Chemicals, Rosemont, Ill. Under the tradename BENZOFLEX (eg, BENZOFLEX400, polypropylene glycol dibenzoate).

(Condensate of polyhydric ether alcohol and polybasic acid)

Next, the condensate of polyhydric ether alcohol and polybasic acid used in the present invention will be described. The condensate of polyhydric ether alcohol and polybasic acid of the present invention represents a condensation oligomer of dicarboxylic acid and polyetherdiol. As dicarboxylic acid, the C4-C12 aliphatic dicarboxylic acid residue or C8-C12 aromatic dicarboxylic acid residue described in the condensate of polyhydric alcohol and polybasic acid is used as it is.

In the present invention, in order to suppress contamination of the flexible support, in the condensate of a polyhydric ether alcohol and a polybasic acid, at least one of the carbon atoms adjacent to the hydroxyl group of the polyvalent ether alcohol is preferably secondary carbon or tertiary carbon. Do.

Next, as polyether which has a C2-C12 aliphatic glycol, polyethylene ether glycol, polypropylene ether glycol, polytetramethylene ether glycol, and a combination thereof are mentioned. Commercially available polyetherglycols that are typically useful include Carbowax resins, Pluronics resins, and Niax resins. In the production of the polyester polyether plasticizer used in the present invention, a commonly used polymerization method well known to those skilled in the art can be used.

Examples of the condensate of polyhydric ether alcohol and polybasic acid include condensates of polyhydric ether alcohol and polybasic acid described in US Patent No. 4,349,469. Basically, for example, a condensate of polyhydric ether alcohol and polybasic acid synthesized from 1,4-cyclohexanedicarboxylic acid as dicarboxylic acid and 1,4-cyclohexanedimethanol and polytetramethylene ether glycol as polyether to be. As a condensate of other useful polyhydric ether alcohol and a polybasic acid, the compound (oligomer) whose molecular weight is the said preferable range among the things shown below can be used, for example. Specific examples thereof include commercially available resins such as copolymers such as Hytrel copolyesters manufactured by DuPont and Galflex polymers manufactured by GAF. These can use the material of Unexamined-Japanese-Patent No. 5-197073. It is commercially available from ADEKA Co., Ltd. as an adadecaser RS series, and can be used. Moreover, the polyester ether type plasticizer which is an alkyl-functionalized polyalkylene oxide is commercially marketed under the brand name PYCAL from ICI Chemicals, Wilmington, Delaware (for example, PYCAL94 and phenyl ester of polyethylene oxide). .

(Condensate of polyhydric alcohol and polybasic acid and condensate of isocyanate compound)

Moreover, the condensate of the polyhydric alcohol, polybasic acid, and the condensate of an isocyanate compound used by this invention are demonstrated. The condensate can be obtained by condensation of a condensate of a polyhydric alcohol with a polybasic acid and an isocyanate compound. First, as a condensate of a polyhydric alcohol and a polybasic acid, the condensate of a polyhydric alcohol and a polybasic acid before sealing both ends can be used as it is, and the above-mentioned raw material can be preferably used in the condensate of a polyhydric alcohol and a polybasic acid. .

A diisocyanate component to form a polyurethane structure include ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, etc. represent _{OCN (CH 2) p NCO (} p = 2 ~ 8) polymethylene is a Isocyanates, and aromatic diisocyanates such as p-phenylenedi isocyanate, tolylene diisocyanate, p, p'-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, and further, m-xylylene diisocyanate are used. However, the present invention is not limited thereto. Among these, tolylene diisocyanate, m-xylylene diisocyanate, and tetramethylene diisocyanate are especially preferable.

In the present invention, the synthesis of a condensate of a polyhydric alcohol and a polybasic acid and an isocyanate compound can be easily obtained by a synthesis method of a conventional method of mixing polyester diols and diisocyanates as raw materials and heating them under stirring. These can use the material described in Unexamined-Japanese-Patent No. 5-197073, Unexamined-Japanese-Patent No. 2001-122979, Unexamined-Japanese-Patent No. 2004-175971, Unexamined-Japanese-Patent No. 2004-175972, etc., for example.

(High Polymer Compounds Other Than Cellulose Ester)

In this invention, in addition to a cellulose ester, other high molecular compounds can also be used together. As the high molecular compound, acrylic polymers such as aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, polyacrylic acid esters, and polymethacrylic acid esters (as ester groups include methyl group, ethyl group, propyl group, butyl group, isobutyl group, Pentyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, nonyl, isononyl, tert-nonyl, dodecyl, tridecyl, stearyl, oleyl, benzyl, phenyl, etc. ), Vinyl polymers such as polyvinyl isobutyl ether and polyN-vinylpyrrolidone, styrene polymers such as polystyrene and poly4-hydroxystyrene, polyethers such as polyethylene oxide and polypropylene oxide, polyamide, poly Urethane, polyurea, phenol-formaldehyde condensates, urea-formaldehyde condensates, vinyl acetate and the like.

These polymer compounds may be homopolymers composed of one type of repeating unit, or may be a copolymer having a plurality of repeating structures. Moreover, you may use together and use 2 or more types of said polymers. These polymer compounds may be used alone, or a mixture thereof may be used to obtain the same effects. Among these, copolymers with polyacrylic acid esters, polymethacrylic acid esters or other vinyl monomers are preferable, and acrylic polymers such as polyacrylic acid esters and polymethacrylic acid esters (as ester groups include methyl group, ethyl group, propyl group, A high molecular compound based on butyl group, hexyl group, cyclohexyl group, 2-ethylhexyl group, isononyl group, and oleyl group) is preferable.

[Thickener]

It is preferable that the optical film of this invention contains a thickener further in addition to said additive. As a result, since the viscosity of the dope can be increased, and the discharge pressure from the die described later can be increased to suppress linear irregularities, the amount of addition can be appropriately set within a range that does not impair fluidity, and the temperature dependence on the dope viscosity is observed. Compounds are more preferably used. The thickener can be used without particular limitation as long as it is a compound that increases the viscosity of the dope, and can be appropriately used while checking the balance with other required properties.

Examples of thickeners include gelling agents, and specifically, oil gelling agents (for example, described in JP-A-2002-322294), organic gelling agents (for example, JP-A-A). 2006-96821), a food gelling agent (for example, described in Unexamined-Japanese-Patent No. 2003-180265), etc. can be used suitably. Specific examples of the food gelling agent (thickener) include aureobacidium culture solution, agrobacterium succinoglycan, amarse gum, arabic gum, arabinogalactan, alginic acid, welllan gum, elemi resin, cassia gum , Gati gum, curdlan, carrageenan, karaya gum, carob bean gum, xanthan gum, chitin, chitosan, guar gum, guar gum enzyme lysate, glucosamine, yeast cell wall, siliumside gum, artemisia halidedendroturtzide Gum, gellan gum, tamarind gum, tamarind seed gum, tara gum, dextran, tragacanth gum, toro aoi, naphtha bacterium, microfibrous cellulose, percelane, ferulic acid, gloiofeltis purkata extract, Pullulan, pectin, macrohomosis gum, peach resin, lsamsan gum, levan, met, glucomannan, hemicellulose, soybean hemicellulose, fermented cellulose, gelatin, carboxymethylcellulose, okra extract, seaweed cellulose, brown algae Extracts, gluten, gluten breakdown products, konjac sweet potato extract, sweet potato cellulose, soybean polysaccharides, natadeco, rennet casein and the like, and the like, and Japanese Patent Application Laid-Open No. 2003-180265 and the like.

[Humidity dependency reducing agent]

In addition to the above additives, the optical film of the present invention may further contain a humidity dependency reducing agent in which ΔRth (A) defined by the following formula (A) is -100 or more and less than 0 nm as a compound that reduces the humidity dependency. . When such an additive is used in combination, the humidity dependency of Rth can be reduced more efficiently, so that the total amount of the additive can also be reduced. Therefore, it is preferable from the viewpoint of contamination suppression of the flexible support.

Formula (A) ΔRth (A) = (ΔRth (rh, A)-ΔRth (rh, 0)) / Q [wherein, ΔRth (rh, A) is 25 ° C. Relative humidity of the film to which the compound is added. The value which subtracted Rth in 25 degreeC and relative humidity 80% from Rth in 10% is shown, (DELTA) Rth (rh, 0) shows the 25 degreeC and relative humidity of 10% of the film in which the compound is not added. Represents the value obtained by subtracting Rth at 25 ° C and a relative humidity of 80% from Rth of Q, and Q represents the mass of the compound when the mass of the cellulose ester in the film is 100.]

When such a compound is used, ΔRth can be effectively reduced even with a small amount of addition, so that the total amount of the additive to the cellulose ester can be reduced, for example, to suppress volatilization of the additive in the film forming process or to convey the film. Can be improved or the bleed out of the film can be suppressed. As for (DELTA) Rth (A), -50-10 nm is more preferable, and -30-0 nm is still more preferable.

As such a compound, the compound which has a hydrogen bondable group and has high hydrogen bondable group density per molecular weight is mentioned. The hydrogen bonding group is preferably a group containing at least one -OH group or -NH group, and for example, hydroxyl group (-OH), carboxyl group (-COOH), carbamoyl group (-CONHR), More preferred are pamoyl group (-SONHR), ureido group (-NHCONHR), amino group (-NHR), urethane group (-NHCOOR), and amide group (-NHCOR). R represents a hydrogen atom, a hydroxyl group, an amino group, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms or a heterocyclic group, preferably a hydrogen atom. More preferably, they are an amino group, a hydroxyl group, a carboxyl group, a carbamoyl group, a sulfamoyl group, or a ureido group, More preferably, they are an amino group and a hydroxyl group. And it is further more preferable that at least 1 is a phenolic hydroxyl group among hydroxyl groups.

As a compound which reduces the temperature dependency of retardation, the following compounds are mentioned as a specific example, for example.

(Compound having a hydroxyl group)

As a compound containing the hydroxyl group used preferably by this invention, More preferably, as a compound containing a phenolic hydroxyl group, it is described in pages 13-19 of Unexamined-Japanese-Patent No. 2008-89860, for example. Compound A and the compound represented by general formula (I) described in the pages 7-9 of Unexamined-Japanese-Patent No. 2008-233530 can be used preferably.

(Compound Having Amino Group)

Although it does not specifically limit as a compound containing the amino group used preferably by this invention, It is preferable that it is a compound represented by following General formula (1) or (2).

In general formula (1)

(3)

(In General Formula (1), Ra represents an alkyl group, an alkenyl group, an alkynyl group, a heterocyclic group or an aryl group. X ¹ , X ² , X ³ and X ⁴ each independently represent a single bond or a divalent linking group. R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group or a heterocyclic group)

In general formula (2)

[Formula 4]

(In General Formula (2), Rb and Rc each independently represent an alkyl group, an alkenyl group, an alkynyl group, a heterocyclic group, or an aryl group. X ⁵ and X ⁶ each independently represent a single bond or a divalent linking group. R ⁵ and R ⁶ each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group or a heterocyclic group)

Said X <^1> -X <^6> represents a single bond or a bivalent coupling group, respectively, may be same or different, and it is preferable that it is selected from the group represented by following General formula (3) as a bivalent coupling group.

In general formula (3)

[Chemical Formula 5]

Hereinafter, the compound which can be used suitably for this invention as a compound which has an amino group is shown.

[Chemical Formula 6]

[Formula 7]

[Formula 8]

Moreover, as a compound which has an amino group, it is also preferable to set it as a pyridine or a pyrimidine parent nucleus, to have an amino group as a substituent in any position which can be substituted, and it is also preferable that it is a compound represented by following General formula (3).

In general formula (3)

[Chemical Formula 9]

In the general formula (3), Y represents a methine group or a nitrogen atom. Qa, Qb and Qc each independently represent a single bond or a divalent linking group. Ra, Rb, and Rc are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, a cyano group, a halogen atom, A substituted or unsubstituted heterocyclic group or -N (Rd) (Rd '), Rd and Rd' may each independently represent a hydrogen atom or a substituent, and Rd and Rd 'may be linked to each other to form a ring; . Ra and Rb may be connected to each other to form a ring. X ¹ represents a single bond or a divalent linking group selected from the following divalent linking group (L). X ² represents a single bond or a divalent linking group. R ¹ and R ² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted complex It may represent a ring group, and R <^1> and R <^2> may mutually connect and form a ring.

Connected group (L)

[Formula 10]

(In each formula, * side is a connection site with the nitrogen atom substituted by the nitrogen-containing aromatic ring in the compound represented by the said General formula (3), and ^Rg is a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkene. Or a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group)

In General Formula (3), Y represents a methine group or a nitrogen atom. In view of increasing hydrogen bonding, Y preferably represents a nitrogen atom.

In General Formula (3), Qa, Qb, and Qc each independently represent a single bond or a divalent linking group.

When Qa, Qb, and Qc represent a bivalent coupling group, an oxygen atom, a sulfur atom, or -N (Rf)-is preferable as the bivalent coupling group (Rf represents a hydrogen atom or an alkyl group).

When Rf represents an alkyl group, a C1-C10 alkyl group is preferable and a C1-C5 alkyl group is more preferable.

Qa preferably represents a single bond, an oxygen atom, or -NH-, and more preferably represents a single bond or an oxygen atom.

Qb preferably represents a single bond.

Qc preferably represents a single bond.

In general formula (3), Ra, Rb, and Rc are respectively independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group , A cyano group, a halogen atom, a substituted or unsubstituted heterocyclic group, or -N (Rd) (Rd '), Rd and Rd' each independently represent a hydrogen atom or a substituent, Rd and Rd 'each other You may connect and form a ring. Ra and Rb may be linked to each other to form a ring.

When Ra, Rb, and Rc represent an alkyl group, it is preferable that it is C1-C12, It is more preferable that it is C1-C8, It is further more preferable that it is C1-C6, It is especially preferable that it is C1-C4 .

When Ra, Rb, and Rc represent an alkenyl group, it is preferable that it is C2-C12, It is more preferable that it is C2-C6, It is especially preferable that it is C2-C4.

When Ra, Rb, and Rc represent an alkynyl group, it is preferable that it is C2-C12, It is more preferable that it is C2-C6, It is especially preferable that it is C2-C4.

When Ra, Rb, and Rc represent an aryl group, it is preferable that it is C6-C18, It is more preferable that it is C6-C12, It is especially preferable that it is C6 (phenyl group).

When Ra, Rb, and Rc represent a heterocyclic group, a morpholinyl group etc. are mentioned.

When Ra, Rb, and Rc represent -N (Rd) (Rd '), it is preferable that Rd or Rd' is a hydrogen atom.

Ra, Rb, and Rc may have a substituent and are the same as the substituent which Ra in said General formula (1) may have.

Ra and Rb may be linked to each other to form a ring. The ring in the case of forming the ring is preferably a nitrogen-containing aromatic ring, and more preferably an imidazole ring.

It is preferable that Ra is a hydrogen atom, an alkyl group, or an aryl group, and it is more preferable that it is a hydrogen atom or an alkyl group.

It is preferable that Rb is a hydrogen atom.

Rc is preferably -N (Rd) (Rd ').

Rd and Rd 'each independently represent a hydrogen atom or a substituent, and Rd and Rd' may be linked to each other to form a ring. When Rd and Rd 'represent a substituent, the substituent is the same as the substituent which said Ra, Rb, and Rc may have. In addition, Rd and Rd 'may further have a substituent and are the same as the substituent which said Ra, Rb, and Rc may have as said further substituent.

In General Formula (3), X ¹ represents a single bond or a divalent linking group selected from the linking group group (L).

X ¹ is more preferably any of the following three types of linking groups, and still more preferably a carbonyl group.

[Formula 11]

In General Formula (3), X ² represents a single bond or a divalent linking group. Specific examples and preferred ranges when X ² represents a divalent linking group are the same as specific examples and preferred ranges when Qa, Qb and Qc represent a divalent linking group.

X ² preferably represents a single bond.

In General Formula (3), R ¹ and R ² each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, Or a substituted or unsubstituted heterocyclic group may be represented, and R ¹ and R ² may be linked to each other to form a ring.

When R <^1> and R <^2> represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group, As a specific example and preferable range of an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group, it is said Ra It is the same as the specific example and the preferable range at which Rb, and Rc represent an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group. Moreover, the example of the substituent which R <^1> and R <^2> may have is also the same as the example of the substituent which said Ra, Rb, and Rc may have.

R ¹ preferably represents a substituted or unsubstituted aryl group. As the substituent which the aryl group may have, an alkyl group, an alkoxy group, a cyano group, a nitro group, a halogen atom, a substituted or unsubstituted carbamoyl group, or a substituted or unsubstituted sulfamoyl group is preferable, and the number of carbon atoms is 1 More preferred are an alkyl group of 8 to 8, an alkoxy group of 1 to 8 carbon atoms, a halogen atom, a substituted or unsubstituted carbamoyl group, or a substituted or unsubstituted sulfamoyl group. As a substituent which the said carbamoyl group or sulfamoyl group may have, an alkyl group is preferable.

R ² preferably represents a hydrogen atom.

It is preferable that the compound represented by the said General formula (3) is a compound represented with the following general formula (4).

In general formula (4)

[Chemical Formula 12]

Formula (4) in the Y, Qa, Qb, Ra, Rb, X ^1, X ^2, R ^1, and R ² is Y, Qa, Qb, Ra, Rb, X ¹ in each of the general formula (3), It has the same meaning as X ² , R ¹ , and R ² . X ³ represents a single bond or a linking group selected from the divalent linking group (L). X ⁴ represents a single bond or a divalent linking group. R ³ and R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted complex It may represent a ring group, and R <^3> and R <^4> may mutually connect and form a ring.

Formula (4) in the Y, Qa, Qb, Ra, Rb, X ^1, X ^2, R ^1, and R ² is Y, Qa, Qb, Ra, Rb, X ¹ in each of the general formula (3), It is synonymous with X <^2> , R <^1> , and R <^2> , and a specific example and a preferable range are also the same.

In general formula (4), X <^3> represents a single bond or the said bivalent coupling group group. Specific examples and preferred ranges of X ³ are the same as the specific examples and preferred ranges of X ¹ in General Formula (3).

In General Formula (4), X ⁴ represents a single bond or a divalent linking group. Specific examples and preferred ranges of X ⁴ are the same as the specific examples and preferred ranges of X ² in General Formula (1).

In general formula (4), R <^3> and R <^4> is respectively independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, Or a substituted or unsubstituted heterocyclic group, and R ³ and R ⁴ may be linked to each other to form a ring. Specific examples and preferred ranges of R ³ and R ⁴ are the same as those of R ¹ and R ² in the general formula (3).

It is preferable that the compound represented by the said General formula (4) is a compound represented by the following General formula (5).

In general formula (5)

[Chemical Formula 13]

Y, Qa, and Ra in General formula (5) have the same meaning as Y, Qa, and Ra in General formula (4), respectively. Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group.

Y, Qa, and Ra in General formula (5) are synonymous with Y, Qa, and Ra in General formula (4), respectively, and a specific example and a preferable range are also the same.

In General Formula (5), Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group. The specific example and preferable range of this aryl group are the same as the specific example and preferable range in the case where R <^1> in the said General formula (3) represents an aryl group.

It is preferable that the compound represented by the said General formula (5) is a compound represented by the following General formula (6).

In general formula (6)

[Formula 14]

Formula (6), Qa, Ra, Ar ^1, and Ar ² is of the same meaning as Qa, Ra, Ar ¹ and Ar ² in the general formula (5), respectively.

And general formula (6) in Qa, Ra, Ar ¹ and Ar ² are each the formula (5) as defined in Qa, Ra, Ar ¹ and Ar ^2, specific examples and preferred ranges are also the same.

It is preferable that the compound represented by the said General formula (6) is a compound represented with the following general formula (7).

General formula (7)

[Formula 15]

In the general formula (7), Q ^d represents a single bond, an oxygen atom, or -NH-. R ^a8 represents an alkyl group having 1 to 8 carbon atoms. R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, and carbon atoms having 1 to An alkyl group of 8 or an alkoxy group having 1 to 8 carbon atoms is represented.

In the general formula (7), Q ^d represents a single bond, an oxygen atom, or -NH-. Q ^d is preferably a single bond or an oxygen atom.

In formula (7), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamomo A diary, a C1-C8 alkyl group, or a C1-C8 alkoxy group is shown. R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ represent a hydrogen atom, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, an alkyl group having 1 to 8 carbon atoms, or carbon It is preferable that it is a C1-C8 alkoxy group, and it is more preferable that it is a hydrogen atom or a C1-C8 alkyl group.

Hereinafter, the compound which can be used suitably for this invention as a compound represented by General formula (3) is shown.

[Chemical Formula 16]

[Chemical Formula 17]

[Chemical Formula 18]

[Chemical Formula 19]

[Chemical Formula 20]

[Chemical Formula 21]

[Chemical Formula 22]

(23)

&Lt; EMI ID =

(25)

(26)

Moreover, it is also preferable that it is a compound represented by following General formula (8) as a compound which has an amino group.

General formula (8)

(27)

In General Formula (8), Qa ₈ and Qc ₈ each independently represent a single bond or a divalent linking group. Ra ₈ and Rc ₈ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, a cyano group, a halogen atom, a substituted Or an unsubstituted heterocyclic group or -N (Rd) (Rd '), Rd and Rd' each independently represent a hydrogen atom or a substituent, and Rd and Rd 'may be linked to each other to form a ring. X ⁸¹ represents a single bond or a divalent linking group selected from the divalent linking group (L). X ⁸² represents a single bond or a divalent linking group. R ⁸¹ and R ⁸² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted complex It may represent a ring group, and R ⁸¹ and R ⁸² may be linked to each other to form a ring.

In the general formula (8), specific examples of Qa and Qc _{8 8} is identical to the Qa in the general formula (3).

In General Formula (8), specific examples of Ra ₈ and Rc ₈ are the same as Ra in General Formula (3).

In general formula (8), the preferable range of X ⁸¹ is the same as X <^1> in general formula (3).

In General Formula (8), the preferable range of X ⁸² is the same as X ² in General Formula (3).

In General Formula (8), the preferable range of R ⁸¹ is the same as that of R ¹ in General Formula (3).

In General Formula (8), the preferable range of R ⁸² is the same as that of R ² in General Formula (3).

Moreover, as a compound which has an amino group, it is also preferable that it is a compound represented by following General formula (9).

General formula (9)

(28)

In General Formula (9), Qa ₉ represents a single bond or a divalent linking group. Ra ₉ is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, a cyano group, a halogen atom, a substituted or unsubstituted heterocyclic ring Group or -N (Rd) (Rd '), Rd and Rd' respectively independently represent a hydrogen atom or a substituent, and Rd and Rd 'may mutually connect and form a ring. X ⁹¹ represents a single bond or a linking group selected from the divalent linking group (L). X ⁹² to X ⁹⁴ each independently represent a single bond or a divalent linking group. R ⁹¹ to R ⁹⁴ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkynyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted complex. It represents a cyclic group. R ⁹¹ and R ⁹² , and R ⁹³ and R ⁹⁴ may be linked to each other to form a ring.

In the general formula (9), specific examples of Qa Qa ₉ is the same as in the general formula (3).

In general formula (9), the specific example of Ra ₉ is the same as Ra in general formula (3).

In the general formula (9), a preferable range of X ⁹¹ are the same as X ¹ in the general formula (3).

In general formula (9), the preferable range of X <^92> -X <^94> is the same as X <^2> in general formula (3).

In General Formula (9), the preferable range of R ⁹¹ is the same as that of R ¹ in General Formula (3).

In general formula (9), the preferable range of R <^92> -R <^94> is the same as that of R <^2> in general formula (3).

Although the specific example of a compound represented by General formula (8) or (9) is shown below, it is not limited to these.

[Formula 29]

(30)

The compound having an amino group is also preferably a compound represented by the following general formula (10).

General formula (10)

(31)

In the general formula (10), X ²¹ to X ²⁶ each independently represent a single bond or a divalent linking group. R ²¹ to R ²⁶ each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group or a heterocyclic group.

In General Formula (10), the specific example in the case where X ²¹ to X ²⁶ represent a divalent linking group is the same as the specific example in the case where X ¹ in General Formula (1) represents a divalent linking group. In General Formula (10), it is preferable that X ²¹ to X ²⁶ are a single bond.

In General Formula (10), the specific examples of X ²¹ to X ²⁶ are the same as the specific examples of R ¹ in General Formula (1). In general formula (10), it is preferable that R <^21> , R <^23> and R <^25> is a hydrogen atom and R <^22> , R <^24> and R <^26> are an aryl group.

As a specific example of a compound represented by General formula (10), although the following compounds are mentioned, for example, it is not limited to these.

(32)

[Compounds to Improve Durability of Retardation]

The optical film of this invention can also contain the compound which improves the durability of retardation. The durability of retardation includes the durability observed as the retardation change when the film is kept in a moist heat environment, and the retardation change when the film is kept in a moist heat environment after the film is in the form of a polarizing plate. The former can be improved by using a condensate containing the polyhydric alcohol component having at least 3 carbon atoms or more described above, and / or controlling the rate of dimensional change described later. Moreover, regarding the latter, it is within the range of the preferable (number average) molecular weight of the compound which has the above-mentioned condensate containing the polyhydric alcohol component of C3 or more of above-mentioned, and / or the compound which has the above-mentioned repeating unit (600-50000 It can be improved by setting to a high molecular weight at) and / or by adding a compound that improves the durability of the retardation. As such a compound, the compound which has a basic functional group in a molecule | numerator can be used, For example, the following compound is mentioned as a specific example.

(33)

(34)

[Cellulose ester]

Next, the cellulose ester in this invention is demonstrated.

The optical film of this invention contains a cellulose ester, It is preferable that cellulose ester content is 30-98 mass%, It is more preferable that it is 50-95 mass%, It is still more preferable that it is 70-92 mass%, 80- Most preferably, it is 90 mass%. Thereby, suitable moisture permeability can be provided to a film, and the optical film excellent in polarizing plate workability can be manufactured.

The cellulose ester used for the optical film of this invention is ester of the cellulose which is a raw material, and an acid, It is preferable that it is a C2-C22 carboxylic acid ester (so-called cellulose acylate), and is a C6 or less lower fatty acid ester It is more preferable. In the cellulose acylate of the present invention, as a method for measuring the degree of substitution of acetic acid and / or fatty acid having 3 to 22 carbon atoms substituted with a hydroxyl group of cellulose, the method according to ASTM D-817-91 or the NMR method Can be mentioned. And in the case of C2-C22 cellulose acylate, the condensate which has a repeating unit is used, Especially when it is C2 cellulose acetate, In addition to this, the adduct which has a repeating unit is also used preferably, a liquid crystal display device Can improve the light unevenness.

Examples of the cellulose of the cellulose ester raw material used in the present invention include cotton linter and wood pulp (softwood pulp, softwood pulp), and the like, and cellulose esters obtained from any raw material cellulose may be used. For detailed descriptions of these raw celluloses, for example, plastic material courses (17) fibrinous resins (Maruzawa, Utazer, Japan Industrial Newspaper, 1970). Cellulose described in the above) can be used, and the optical film of the present invention is not particularly limited.

In the cellulose acylate of the present invention, the degree of substitution of the cellulose with respect to the hydroxyl group is not particularly limited. From the viewpoint of increasing the viscosity of the dope, increasing the discharge pressure from the die described later to suppress linear irregularities, the dissolution is poor. It is preferable that substitution degree is high in the range which does not produce | generate. Moreover, in order to provide suitable moisture permeability and hygroscopicity to a film, it is preferable that the acyl substitution degree with respect to the hydroxyl group of a cellulose is 2.60-3.00. Furthermore, it is preferable that substitution degree is 2.70-2.98, It is more preferable that it is 2.80-2.96, It is still more preferable that it is 2.87-2.94. Moreover, the acyl substitution degree (DSs) of the cellulose acylate contained in 1 micrometer area | region from the film surface, and the acyl substitution degree (DSc) of the cellulose acylate contained in 1 micrometer area | region from the thickness direction center of an optical film, It is preferable to satisfy the relationship DSs ≤ DSc. DSs can measure, for example, a powder obtained by cutting a 1 µm area from a film surface with a razor blade or the like by a known method, and DSc similarly scrapes the film to the center in the thickness direction (for example, 50 If it is a micrometer film, after shaving to 25 micrometers, the area | region of 1 micrometer is further scraped off) can be measured.

The acyl group having 2 to 22 carbon atoms may be an aliphatic group or an aromatic group in the acetic acid and / or fatty acid having 3 to 22 carbon atoms substituted with a hydroxyl group of cellulose, and is not particularly limited, and may be a single type or a mixture of two or more types. They are alkylcarbonyl ester, alkenylcarbonyl ester, aromatic carbonyl ester, aromatic alkylcarbonyl ester, etc. of cellulose, for example, and may have a group substituted further, respectively. Preferred examples of these acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, Nonyl, t-butanoyl, cyclohexanecarbonyl, oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like. Of these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, t-butanoyl, oleoyl, benzoyl, naphthylcarbonyl and cinnamoyl are preferable, and acetyl, propionyl and butanoyl desirable.

Among these, from the viewpoints of ease of synthesis, cost, and easy control of substituent distribution, a mixed ester of an acetyl group, an acetyl group, and a propyl group is preferable, and an acetyl group is particularly preferable.

It is preferable that it is 180-550, as for the polymerization degree of the cellulose acylate used preferably in this invention, 200-500 are more preferable, 250-450 are more preferable. If the polymerization degree is too high, the viscosity of the dope solution of cellulose acylate tends to be high, and film production tends to be difficult due to flexibility. If the polymerization degree is too low, the strength of the produced film tends to be lowered. The average degree of polymerization can be measured by extreme viscosity method (Uta Kazuo, Saito Hideo, Textile Journal, Vol. 18, No. 1, pp. 105-120, 1962) by Uta et al. And is described in detail in Japanese Patent Application Laid-Open No. 9-95538.

The molecular weight distribution of the cellulose acylate preferably used in the present invention is evaluated by gel permeation chromatography, and its polydispersity index Mw / Mn (Mw is the mass average molecular weight, Mn is the number average molecular weight) It is preferable that the distribution is narrow. As a specific value of Mw / Mn, it is preferable that it is 1.0-4.0, It is more preferable that it is 2.0-3.5, It is most preferable that it is 2.3-3.4.

When the low molecular weight component is removed, the average molecular weight (polymerization degree) is increased, but the viscosity is useful because it is lower than the usual cellulose acylate. The cellulose acylate with few low molecular weight components can be obtained by removing the low molecular weight component from the cellulose acylate synthesized by a conventional method. Removal of the low molecular weight component can be performed by washing a cellulose acylate with a suitable organic solvent. Moreover, when manufacturing the cellulose acylate with few low molecular components, it is preferable to adjust the amount of sulfuric acid catalysts in an acetalization reaction to 0.5-25 mass parts with respect to 100 mass parts of cellulose. When the amount of the sulfuric acid catalyst is in the above range, cellulose acylate (which has a low molecular weight distribution) that is preferable also in terms of molecular weight distribution can be synthesized. When used at the time of manufacture of the cellulose acylate film of this invention, it is preferable that the moisture content of a cellulose acylate is 2 mass% or less, More preferably, it is 1 mass% or less, Especially preferably, it is 0.7 mass% or less. Generally cellulose acylate contains water, and the water content is 2.5-5 mass%. In order to make the water content of cellulose acylate as mentioned above in this invention, it is necessary to dry, and the method will not be specifically limited if it becomes the target water content. Regarding these cellulose acylates of the present invention, the raw material surface and the synthesis method thereof are detailed in pages 7 to 12 in the Invention Association Publication (Publication No. 2001-1745, issued March 15, 2001, Invention Association). It is described.

In the present invention, the cellulose acylate can be used by mixing two or more kinds of cellulose acylates, which are single or different, from the viewpoints of substituents, substitution degree, polymerization degree, molecular weight distribution, and the like.

[Retardation adjusting agent]

Although the optical anisotropy of the optical film of this invention can be controlled by addition of the compound which has a repeating unit mentioned above, you may add a different optical anisotropy modifier further according to the retardation made into the objective. For example, the compound which reduces Rth described in page 23 from page 23 of Unexamined-Japanese-Patent No. 2006-30937 can also be added, The compound which raises Rth, specifically, the compound which has one or more aromatic rings is preferable, It is more preferable to have 2-15 pieces, and it is still more preferable to have 3-10 pieces. It is preferable that each atom other than the aromatic ring in a compound is arrangement | positioning near the same plane as an aromatic ring, and, when it has two or more aromatic rings, it is preferable that aromatic rings also arrange | position near to the same plane. Moreover, in order to raise Rth selectively, it is preferable that the presence state in the film of an additive exists in the direction in which an aromatic ring plane is parallel to a film surface.

The said additive may be used independently and may be used in combination of 2 or more types of additives.

As an additive which has the effect of raising Rth, the plasticizer as described in pages 33-34 of Unexamined-Japanese-Patent No. 2005-104148, and the optically anisotropic control agent as described in pages 38-89 of Unexamined-Japanese-Patent No. 2005-104148 specifically, are mentioned. Etc. can be mentioned. Although the detailed reason is unknown, in this invention, in order to suppress the visibility of the circular light nonuniformity visually observed when the liquid crystal display device is observed obliquely, it is preferable to contain the low molecular compound which has an effect which raises Rth.

[Retardation]

It is important for the optical film of this invention to adjust Re and Rth (it is defined by following formula (I) and formula (II)) measured by wavelength 590nm suitably according to a use, and this value is a thing of the substituent of a cellulose ester. Kind and substitution can also be controlled by the kind and addition amount of the compound which has the repeating unit mentioned above, the film thickness of a film, the process conditions at the time of film forming, an extending process, etc.

When reducing the retardation of the optical film of this invention and using it for the liquid crystal panel use of IPS mode, for example, it is preferable to satisfy following formula (IIIa) and (IVa), and is also used as a protective film The functional layer mentioned later can also be formed using a film as a support body. Thereby, for example, contrast of the display screen of a liquid crystal display device can be improved, a viewing angle characteristic, or a color taste can be improved.

Formula (I) Re = (nx-ny) × d (nm)

Formula (II) Rth = {(nx + ny) / 2-nz} × d (nm)

Formula (IIIa) Re <10

Formula (IVa) | Rth | <25

(Wherein nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the thickness (nm) of the film)

In this case, although the orientation of the in-plane slow axis is not specifically limited, It is preferable that it is substantially parallel or substantially orthogonal with respect to the orientation in which the elasticity modulus of a film becomes largest in surface. Re is more preferably 0 to 5 nm. Moreover, as for Rth, -20-5 nm is more preferable, and -10-0 nm is still more preferable. When using the cellulose acylate film of this invention as a liquid crystal cell side protective film of the polarizing plate of a liquid crystal display device, when Re and Rth are in the said range, the light leakage from a diagonal direction can be improved more and display quality can be improved. .

In the case of actively expressing the retardation of the optical film of the present invention and using it for a liquid crystal panel use of, for example, VA mode, it is preferable to satisfy the following formulas (IIIb) and (IVb), and also use it as a protective film. The functional layer mentioned later can also be formed using the liquid crystal film used as a support body. Thereby, for example, contrast of the display screen of a liquid crystal display device can be improved, a viewing angle characteristic, or a color taste can be improved.

Formula (IIIb): 30 ≤ Re ≤ 85

Formula (IVb): 80 ≤ Rth ≤ 300

In this case, although the orientation of the in-plane slow axis is not specifically limited, It is preferable that it is substantially parallel or substantially orthogonal with respect to the orientation in which the elasticity modulus of a film becomes largest in surface, and it is more preferable that it is substantially parallel.

Moreover, when expressing retardation of the optical film of this invention actively and using it for the liquid crystal panel use of IPS mode, for example, it is preferable to satisfy following formula (IIIc) and (Vc), and also it is protection. The functional layer mentioned later can also be formed using the optical film used as a film as a support body. Thereby, for example, contrast of the display screen of a liquid crystal display device can be improved, a viewing angle characteristic, or a color taste can be improved.

Formula (IIIc): 60 ≤ Re ≤ 400

Equation (IVc): -0.5 ≤ Rth / Re ≤ 0.5

In this case, although the orientation of the in-plane slow axis is not specifically limited, It is preferable that it is substantially parallel or substantially orthogonal with respect to the orientation in which the elasticity modulus of a film becomes largest in surface.

Re and Rth can be measured in the following manner.

(Retardation)

In the present specification, Re and Rth (unit: nm) are obtained by the following method. First, after humidifying a film at 25 degreeC and 60% of a relative humidity for 24 hours, using a prism coupler (MODEL20l0 Prism Coupler by Metricon), using a 532 nm solid laser at 25 degreeC and 60% of a relative humidity, The average refractive index n shown by Formula (B) is calculated | required.

Formula (B): n = (n _TE × 2 + n _TM ) / 3

_Wherein n _TE is the refractive index measured in the polarized light in the film plane direction and n _TM is the refractive index measured in the polarized light in the film plane normal direction,

In the present specification, Re (? Nm) and Rth (? Nm) indicate in-plane retardation and retardation in the thickness direction in the wavelength? (Unit: nm), respectively. Re (? Nm) is measured by introducing light having a wavelength of? Nm in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Instruments Co., Ltd.).

When the film to be measured is represented by a monoaxial or biaxial refractive index ellipsoid, Rth (? Nm) is calculated by the following method.

Rth (λ nm) is the Re (λ nm) as the in-plane slow axis (determined by KOBRA 21ADH or WR) as the inclination axis (rotation axis) (when there is no ground axis, any direction within the film plane is Rotation axis) 6 points of light are measured by injecting light having a wavelength of λ nm from the inclined direction, respectively, in a step of 0 ° from the normal direction to 50 ° on the one side from the normal direction of the film, and measuring the total retardation value and the average refractive index. And KOBRA 21ADH or WR is calculated based on the input film thickness value.

In the above, there is no description about?, And when only Re and Rth are described, a value measured using light having a wavelength of 590 nm is shown. In the case of a film having a direction in which the value of retardation becomes zero at any inclination angle from the normal plane as the rotation axis as the rotation axis, the retardation value at the inclination angle greater than the inclination angle is negative. After changing to i), KOBRA 21ADH or WR is calculated.

In addition, with the slow axis as the inclination axis (rotation axis) (when there is no ground axis, any direction in the film plane is the rotation axis), the retardation value is measured from any inclined two directions, and the value and the average refractive index and Based on the input film thickness value, Rth can also be computed by following formula (3) and formula (4).

Equation (3)

[In the formula, Re (&amp;thetas;) represents the retardation value in the oblique direction from the normal direction. Nx represents the index of refraction in the direction of the slow axis in the plane, ny represents the index of refraction in the direction perpendicular to nx in the surface, nz represents the index of refraction in the thickness direction perpendicular to nx and ny, Film thickness.

(4): Rth = ((nx + ny) / 2 - nz) xd

When the film to be measured is a film which can not be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis, Rth (? Nm) is calculated by the following method.

Rth (λ nm) is 10 degrees from -50 degrees to +50 degrees with respect to the film normal direction using Re (λ nm) as the in-plane slow axis (judged by KOBRA 21ADH or WR) as the inclination axis (rotation axis). In each step, 11 points of light are incident from the inclined direction and measured, and KOBRA 21ADH or WR is calculated based on the measured retardation value, the average refractive index, and the input film thickness value. By inputting these average refractive indices and film thickness, KOBRA 21ADH or WR calculates nx, ny, nz. From the calculated nx, ny and nz, Nz = (nx-nz) / (nx-ny) is further calculated.

In addition, in said measurement, the average refractive index can also use the value of the catalog of a polymer handbook (JOHN WILEY & SONS, INC) and various optical films. About the mean refractive index whose value is not already known, it can measure by the method mentioned above. The value of the average refractive index of a main optical film is illustrated below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), polystyrene (1.59).

(Humidity dependence)

In the present invention, the humidity dependency (ΔRe) of Re and the humidity dependency (ΔRth) of Rth are the retardation values of the in-plane direction and the film thickness direction when the relative humidity is H (unit:%): Re (H%). And Rth (H%) are calculated based on the following formula.

ΔRe = Re (10%)-Re (80%)

ΔRth = Rth (10%)-Rth (80%)

Re (H%) and Rth (H%) bond a film to a glass plate through an adhesive at 25 degreeC and 60% of a relative humidity after 24-hour humidity control at 25 degreeC and 60% of a relative humidity. After humidifying for 48 hours at 60 degreeC and 90% of the relative humidity, after 24 hours of humidity control at 25 degreeC and the relative humidity H%, it carried out similarly to the method mentioned above in 25 degreeC and the relative humidity H%, and made it into relative humidity H%. The retardation value when the measurement wavelength in 590 nm is measured and calculated. In addition, in the case where it is simply expressed as Re without specifying the relative humidity, the value measured at the relative humidity of 60% described above is shown.

It is preferable that the retardation value at the time of changing the humidity of the cellulose acylate film of this invention satisfy | fills the following relational formulas.

ΔΔ Re <30, and

ΔΔRth <30

Moreover, it is more preferable to satisfy the following relational formula.

ΔΔRe 15 and

ΔΔRth <15

Moreover, it is more preferable to satisfy the following relational formula.

| Re |

ΔΔRth <10

Moreover, it is most preferable to satisfy the following relationship.

| ΔRe | <5, and,

ΔΔRth <5

By controlling the retardation value when the humidity is changed, the retardation change when the external environment changes can be reduced, and a highly reliable liquid crystal display device can be provided. Moreover, the preferable effect that the circular color nonuniformity visually recognized when the display surface is observed obliquely by a liquid crystal display device under specific conditions is also obtained by reducing (DELTA) Rth of the optical film of this invention. In order to reduce ΔRe and ΔRth effectively, it is also preferable to use the above-mentioned humidity dependency reducing agent together.

[Dimension Change Rate of Film]

The dimensional change rate of the optical film of this invention can be measured as the absolute value of the value which divided | segmented the dimensional change at the time of standing for 24 hours on 60 degreeC and 90% RH conditions, and reduced this, and rolled over time by reducing this By suppressing deterioration in appearance or using such a film as a protective film for a polarizing plate, peeling and curling during polarizing plate processing can be suppressed, and furthermore, curl and dimensional change rate of the obtained polarizing plate can be suppressed. At this time, it is especially effective to suppress the rate of dimensional change in the width direction of the roll. It is preferable that the dimension change of the optical film of this invention is 3% or less, but when it considers compatibility with productivity, it is preferable that it is 0.05-2%, It is more preferable that it is 0.1-1%, It is more preferable that it is 0.1-0.5% desirable.

The dimension change rate of the optical film of this invention can be specifically measured by the following method. First, the film sample which cut out length 12cm (measurement direction), the width | variety 3cm film sample, and the direction orthogonal to this as the longitudinal direction was cut out and made the direction which the elasticity modulus of a film becomes the largest direction, and the A pin hole was drilled at intervals of 10 cm at the sample, and after 24 hours of humidity at 25 ° C. and 60% of relative humidity, the pin hole interval was measured with a pin gauge (a measurement value is referred to as L ₀ ). Subsequently, after holding a sample for 24 hours in 60 degreeC and a humid heat environment of 90% of a relative humidity, after 2 hours of humidity control at 25 degreeC and 60% of a relative humidity, the pinhole space | interval is measured by a pin gauge (measured value is L1 _). I say). Using these measured values, a dimensional change rate is computed by the following formula.

Dimensional rate of change [%] = ｜ (L ₁ -L ₀ ) / L ₀ | × 100

[Coefficient of Humidity Expansion of Film]

In the present invention, the circular color nonuniformity seen when the liquid crystal display device is observed obliquely is not more visually recognized by bringing the humidity expansion coefficient of the film closer to the humidity expansion coefficient of the polarizing film in addition to the above-described humidity dependency of Rth. It turned out. However, since a polarizing plate curl may be influenced by the balance with the optical film used on the opposite side across a polarizing film, it is preferable to set the humidity expansion coefficient of the optical film of this invention suitably. In the present invention, the humidity expansion coefficient is a length of 25 cm (measurement direction), a film sample having a width of 5 cm, and a sample cut out by making the direction perpendicular to the rectangular shape cut out with the direction in which the modulus of elasticity becomes the maximum, respectively. After preparing, the sample drills a pin hole at an interval of 20 cm, and after 24 hours of humidification at 25 ° C. and a relative humidity of 10%, the pin hole interval is measured by a pin gauge (measured value is referred to as L ₀ ). Then, the sample 25 ℃, after 24 hours at a relative humidity of 80% humidity, the length-measuring the distance between the pin holes with the pin gauge (the measurement is referred to as L _1). Using these measured values, the humidity expansion coefficient is calculated by the following equation.

Humidity Expansion Coefficient [ppm /% RH] = {(L _l -L ₀ ) / L ₀ } / 70 × 10 ⁶

The said 70 is the difference (%) of the measured temperature.

Although the humidity expansion coefficient of the film of this invention changes with kinds of the polarizing film and opposing optical film which are used, it is preferable that it is 55 ppm /% RH or less, 3-50 ppm /% RH is more preferable, 5 45 ppm /% RH is more preferable. The humidity expansion coefficient of this invention can be reduced by raising the crystallinity degree of the cellulose acylate contained in the optical film of this invention, extending | stretching the optical film of this invention, etc., for example.

Tensile Modulus of Film

In addition, the circular color nonuniformity visually recognized when the liquid crystal display device is observed obliquely becomes less visible even by reducing the elastic modulus of the film. It is preferable that the tensile elasticity modulus of the optical film of this invention is less than 3.0 GPa, It is more preferable that it is 1.0-3.0 GPa, It is still more preferable that it is 1.2-2.8 GPa. However, in a range satisfying Ct / d ≥ 0.375, it is preferably 3.0 kPa or more, more preferably 3.0-10.0 kPa, still more preferably 3.1-5.0 kPa, most preferably 3.2-4.5 kPa desirable. The latter preferable embodiment can be suitably applied particularly in the case of a film having a thin film thickness, and a preferable effect of particularly improving the appearance when the film is made over time in a rolled state is also obtained. As a specific measuring method, the film sample of length 200mm (measurement direction) and width 10mm is cut out, the distance between chucks is set to 100mm, and it is 25 degreeC using the universal tension tester "STM T50BP" made by Toyo Baldwin Co., Ltd. And the stress in 0.1% stretching and 0.5% stretching at a tensile rate of 10% / min in a 60 RH% atmosphere were measured, and the elastic modulus was calculated | required from the inclination. In the measurement of the elastic modulus, the anisotropy of the elastic modulus can be determined by changing the orientation in which the sample is cut out, and the angle θ between the conveyance direction at the time of manufacture and the orientation in which the elastic modulus is maximum is not particularly limited, but is 0 ± 10 ° or It is preferable that it is 90 +/- 10 degree. In addition, the orientation in which the elastic modulus is maximized may be evaluated as the direction in which the sound wave propagation speed described later is maximized, and in the present invention, unless otherwise specified, the direction in which the sound wave propagation speed is maximized. When there is no description in particular, the value of the elasticity modulus in this invention shows the value of the elasticity modulus in the orientation in which an elasticity modulus becomes the largest.

The relationship between the humidity expansion coefficient and the tensile modulus of the film and the visibility of the color unevenness when the liquid crystal display is observed obliquely is not detailed, but the film has a high rigidity such as glass by adjusting the humidity expansion coefficient and the tensile modulus of the film. It is thought that the internal stress which arises when the environmental humidity changes in the state fixed to the support body can be reduced, As a result, the retardation change of a film can be suppressed more, and color nonuniformity can be reduced.

[Matte Particles]

In the optical film of the present invention, it is preferable to add fine particles as a matting agent. The fine particles used in the present invention include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, calcium silicate hydrate, aluminum silicate, magnesium silicate and calcium phosphate. have. It is preferable that the fine particles contain silicon in view of turbidity reduction, and silicon dioxide is particularly preferable. The fine particles of silicon dioxide preferably have a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more. It is more preferable that the average diameter of a primary particle is 5-16 nm as small as it can lower the haze of a film. 90-200 g / liter or more is preferable, and, as for apparent specific gravity, 100-200 g / liter or more is more preferable. The larger the apparent specific gravity is, the more preferable it is to be able to produce a high concentration dispersion, and the haze and aggregates are quantified.

These fine particles usually form secondary particles having an average particle diameter of 0.1 to 3.0 占 퐉. These fine particles exist as agglomerates of primary particles in the film, and form irregularities of 0.1 to 3.0 占 퐉 on the surface of the film. The secondary average particle size is preferably 0.2 µm or more and 1.5 µm or less, more preferably 0.4 µm or more and 1.2 µm or less, and most preferably 0.6 µm or more and 1.1 µm or less. Primary and secondary particle diameters observed the particle | grains in a film with the scanning electron microscope, and made the diameter of the circle circumscribed to particle | grains a particle diameter. Moreover, the place was changed and 200 particles were observed and the average value was made into the average particle diameter.

As microparticles | fine-particles of silicon dioxide, a commercial item, such as aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd. product) can be used, for example. have. Fine particles of zirconium oxide are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.).

Among these, aerosil 200V and aerosil R972V are fine particles of silicon dioxide having a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more, and the friction coefficient is maintained while keeping the haze of the optical film low. It is especially preferable because the effect of lowering is large.

In this invention, in order to obtain the optical film which has a particle | grain with small secondary average particle diameter, some methods can be considered when preparing the dispersion liquid of microparticles | fine-particles. For example, there is a method in which a fine particle dispersion in which a solvent and fine particles are mixed and stirred is prepared in advance, the fine particle dispersion is added to a separately prepared small amount of solution, stirred and dissolved, and further mixed with the main dope. This method is a preferable preparation method in that the dispersibility of the silicon dioxide fine particles is good and the silicon dioxide fine particles are difficult to be further re-agglomerated. In addition, a small amount of cellulose ester is added to the solvent, followed by stirring and dissolving. Then, fine particles are added to the solvent and dispersed in a disperser to form a fine particle addition liquid, and the fine particle addition liquid is sufficiently mixed with the dope liquid with an in-line mixer. There is also. The present invention is not limited to these methods, but the concentration of silicon dioxide in mixing and dispersing silicon dioxide fine particles with a solvent or the like is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, more preferably 15 to 20% % Is most preferable. The higher the dispersion concentration, the lower the liquid turbidity with respect to the added amount, and the haze and aggregates are positive, which is preferable.

As for the addition amount of the mat agent in a final dope solution, many things are preferable in the range with which the haze of a film is permissible, 0.01-1.0 g per 1 m <2> is preferable, 0.03-0.3g is more preferable, 0.08-0.16g is Most preferred. Moreover, when a cellulose acylate film is formed in a multilayer by the film forming method like a covalent lead, for example, it is preferable to add only to a surface layer side, without adding to an inner layer, in this case, As addition amount, 0.001-2.0 mass% is preferable with respect to solid content contained in dope for surface layers, 0.01-1.0 mass% is more preferable, 0.02-0.5 mass% is more preferable, 0.03-0.3 mass% is the most preferable. Do.

The solvent used for the dispersion is preferably a lower alcohol, and examples thereof include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol and butyl alcohol. Although it does not specifically limit as solvent other than lower alcohol, It is preferable to use the solvent used at the time of film forming of a cellulose acylate.

[Other additives]

In addition to the compound having a repeating unit, the retardation regulator, and the matte particles, the optical film of the present invention includes various additives (for example, a plasticizer, an ultraviolet absorber, a deterioration inhibitor, a release agent, an infrared absorber, a wavelength dispersion regulator, and the like). You may add and they may be solid or oily matter may be sufficient as them. That is, it is not specifically limited in the melting point or boiling point. For example, it is mixing of the ultraviolet absorbing material of 20 degrees C or less and 20 degrees C or more, similarly the plasticizer mixing, etc., for example, are described in Unexamined-Japanese-Patent No. 2001-151901. Furthermore, as an infrared absorbing dye, it is described, for example in Unexamined-Japanese-Patent No. 2001-194522. In addition, although the addition time may be added at any time in a dope manufacturing process, you may add and implement the process of adding and preparing an additive to the last preparation process of a dope preparation process. Furthermore, the addition amount of each material is not particularly limited as long as the function is expressed. Moreover, when an optical film is formed in multiple layers, the kind and addition amount of the additive of each layer may differ. For example, although it is described in Unexamined-Japanese-Patent No. 2001-151902 etc., these are the techniques known conventionally. For details of these, the materials described in detail on pages 16 to 22 are preferably used in the Invention Association Publication (Publication No. 2001-1745, issued March 15, 2001, Invention Association).

[Total Content of Additives (Ct)]

In the optical film of this invention, when adding another additive in addition to the compound which has the above-mentioned repeating unit, it is preferable that the total content (Ct) of an additive is 20-200 phr, and it is more preferable that it is 30-180 phr. It is more preferable that it is 45-150 phr. However, as mentioned above, in the range which satisfy | fills Ct / d≥0.375, 2-100 phr is preferable, as for the total content of an additive, 5-50 phr is more preferable, 6-30 phr is more preferable In some cases, it is desirable.

[Surface Layer Addition of Additives (Cs)]

In the manufacturing method of the optical film of the present invention, from the viewpoint of suppressing the contamination of the dope discharge port, it is preferable to covalently flame as described later. It is preferable to reduce the addition amount Cs) than the inner layer. Therefore, the surface content of the additive is preferably 50 phr or less. However, when the difference between the surface content and the total content described above is too large, for example, a fine wrinkled plane failure may occur, so that the difference between Ct and Cs is 1 to 40. It is preferable that it is phr, It is more preferable that it is 3-35 phr, It is further more preferable that it is 5-30 phr.

[Method of Manufacturing Optical Film]

In order to satisfy the relationship between the addition amount and the film thickness, which is preferable for the purpose of improving the light unevenness, it was estimated that when the addition amount is increased or the film thickness is lowered, the discharge pressure from the die is lowered and linear irregularities are more likely to occur. Moreover, when the addition amount was increased, it was estimated that since the affinity of the material of a die discharge port and dope became high, and die adhesion became high, it became easy to be contaminated. And the manufacturing method of the film of this invention WHEREIN: It turned out that the manufacturing method mentioned later for the purpose of raising the discharge pressure from a die, and the manufacturing method which lowers the addition amount of a surface layer for the purpose of lowering die adhesion are effective for suppressing linear unevenness. .

(Organic solvent in dope solution)

In this invention, it is preferable to manufacture the film containing a cellulose ester by the solvent cast method, and a film is manufactured using the solution (dope) which melt | dissolved the polymer containing cellulose ester in the organic solvent. The organic solvent which is preferably used as the main solvent of the present invention is not particularly limited as long as the polymer containing the cellulose ester is dissolved, but an ester having 3 to 12 carbon atoms, a ketone, an ether, and a carbon atom having 1 to 7 carbon atoms. Preference is given to solvents selected from halogenated hydrocarbons. The esters, ketones and ethers may have a cyclic structure. Compounds having two or more functional groups of esters, ketones and ethers (ie, -0-, -CO- and -CO0-) can also be used as the main solvent, and may have other functional groups such as, for example, alcoholic hydroxyl groups. do.

As for the optical film of the present invention, a chlorinated halogenated hydrocarbon may be the main solvent, or as described in the Invention Association Publication No. 2001-1745 (pages 12 to 16), the non-chlorine solvent may be the main solvent. It does not specifically limit about the optical film of this invention.

In addition, the solvent for the dope solution and film of the present invention is disclosed in the following patents, including the dissolution method thereof, and is a preferred embodiment. They are, for example, Japanese Unexamined Patent Application Publication No. 2000-95876, Japanese Unexamined Patent Application Publication No. 12-95877, Japanese Unexamined Patent Application Publication No. 10-324774, Japanese Unexamined Patent Application Publication No. 8-152514, Japanese Unexamined Patent Application Publication No. 10-330538, Japan Japanese Patent Laid-Open No. 9-95538, Japanese Patent Laid-Open No. 9-95557, Japanese Patent Laid-Open No. 10-235664, Japanese Patent Laid-Open No. 12-63534, Japanese Patent Laid-Open No. 11-21379, Japanese Patent Laid-Open No. 10 Japanese Patent Application Laid-Open No. Hei 10-278056, Japanese Patent Application Laid-open No. Hei 10-279702, Japanese Patent Application Laid-open No. Hei 10-323853, Japanese Patent Application Laid-open No. Hei 10-237186, Japanese Patent Application Laid-open No. Hei 11-60807 It describes in Unexamined-Japanese-Patent No. 11-152342, Unexamined-Japanese-Patent No. 11-292988, Unexamined-Japanese-Patent No. 11-60752, etc. are described. According to these patents, not only the preferable solvent for the cellulose ester of the present invention but also the physical properties of the solution and coexisting substances to coexist are described, which is also a preferred embodiment of the present invention.

(Dissolution step)

The preparation method of the dope solution of the present invention is not particularly limited and may be carried out at room temperature or further by a cooling dissolution method or a high-temperature dissolution method, or a combination thereof. Preparation of the dope solution in this invention, Furthermore, about each process of solution concentrating and filtration accompanying a dissolution process, the invention association published report (air number 2001-1745, issued March 15, 2001, invention association) The manufacturing processes described in detail on pages 22 to 25 are preferably used. Moreover, it is preferable that solid content concentration of a dope is high from a viewpoint of the discharge pressure rise from a die in the range which does not produce melt | dissolution defect.

(Flexible, dry, winding process)

Next, a method for producing a film using the dope solution of the present invention will be described. As the method and equipment for producing the optical film of the present invention, a conventional solution casting film forming method and a solution casting film forming apparatus used for producing a cellulose triacetate film can be used. The dope solution prepared from the dissolver (kiln) is once stored in a storage kiln, the air bubbles contained in dope are defoamed and final preparation is carried out. The dope is fed from the dope outlet to a pressure die through a pressure metering gear pump capable of metering fluid with high precision at high speed, for example, by rotation speed, and the dope is endless from the detention (slit) of the pressure die. The less dry dope film (also called a web) is peeled off from the metal support at a peeling point where the metal support is uniformly flexible on the metal support which is running. Both ends of the web obtained are clipped and conveyed by a tenter while maintaining the width, and dried, the film obtained is then removed from the clip, mechanically conveyed by a roll group in a heating apparatus, and wound up to a predetermined length in roll form by a winder. . The combination of a tenter and a drying apparatus of a roll group changes with the objective. In another embodiment, the above-described metal support is a drum cooled to 5 ° C. or lower, and after gelling the dope extruded from the die on the drum, the film is peeled off at about 1 week and then conveyed while stretching in a pin-shaped tenter. It is possible to take various methods of forming a film by the solvent cast method, such as a drying method.

At this time, in view of the increase in the discharge pressure from the die, the area of the die discharge port is preferably narrow, particularly preferably a narrow width in the web (film) thickness direction. Moreover, it is preferable that a dope temperature is low in the range which a problem does not appear in fluidity from a viewpoint of raising dope viscosity and raising discharge pressure. On the other hand, it is preferable that the temperature of the dope film | membrane on a support body is high in the range which does not interfere with a peeling process from a viewpoint of leveling a less dry dope film | membrane and relieving linear unevenness | corrugation.

In addition, from the viewpoint of increasing the discharge pressure from the die, the dope flow rate discharged from the die is preferably large.

It is preferable that the manufacturing method of the optical film of this invention includes the process of extruding the fluid containing at least the said additive and a cellulose ester from a die, and it is preferable that the liquid supply pressure with respect to a die is 0.5 Mpa or more, and it is 0.7 Mpa or more. It is preferable and it is more preferable that it is 0.8 Mpa or more. Although there is no restriction | limiting in particular as an upper limit, It is preferable that it is 5.0 Mpa or less, It is more preferable that it is 3.0 Mpa or less, It is still more preferable that it is 1.0 Mpa or less.

Moreover, it is preferable that it is 0.2-1.5 mm, and, as for the clearance of the die to discharge, it is more preferable that it is 0.5-1.2 mm.

Moreover, it is effective to raise a casting | flow_spread rate, to cast thicker than desired film thickness, and to reduce film thickness by extending | stretching, for example. The stretching may be wet stretching performed in a state where the amount of residual solvent is large, or dry stretching performed in the absence of residual solvent, and it is preferable that the stretching is performed in-line from the viewpoint of brittleness and productivity. The stretching direction may be longitudinal stretching stretching in the conveying direction, transverse stretching orthogonal to the conveying direction may be used, or diagonal stretching stretching in the inclined direction may be used, and characteristics of the desired film (for example, retardation, elastic modulus, and humidity) may be used. Depending on the coefficient of expansion), these may be performed alone or in combination.

Moreover, it is preferable to be flexible by a covalent smoke method from a viewpoint of suppressing die adhesion. That is, the casting | flow_spread of multiple layers is performed by extruding two or more types of dope from which addition amount differs at least simultaneously or sequentially from the die | dye of die | dye. It is also preferable to adjust the thickness of each layer. At this time, since contamination of the dope discharge port can be suppressed by arrange | positioning the layer with few addition amounts as a surface layer, raising solid content concentration of a surface layer, and raising a film thickness of a surface layer, these factors require a different request | requirement. It can adjust suitably, checking the balance with a characteristic.

In the case of co-linking, for example, a feed block method that can easily adjust the number of layers or a multi-manifold method that is excellent in thickness accuracy of each layer can be used. In the present invention, the feed block method is more preferable. Can be used.

In the solution casting film forming method used for the functional polarizing plate protective film which is the optical member for electronic displays which is the main use of the optical film of this invention, and a silver halide photographic photosensitive material, in addition to a solution casting film forming apparatus, it is the lower layer and the charging In many cases, a coating device is added for surface processing on films such as a protective layer, an anti-halation layer, and a protective layer. These are described in detail in pages 25 to 30 of the Invention Association published report (air number 2001-1745, published March 15, 2001, Invention Association), flexible (including covalent lead), metal supports, It is classified into drying, peeling, etc., and can be used preferably in this invention.

[Heat treatment process]

In the manufacturing method of the optical film of this invention, the process of further heat-processing the said optical film can also be applied as needed. Although the effect of a heat processing process is not specifically limited, By making heat-treatment which temperature and tension control according to the kind of film, it is possible to change the orientation and crystallization of the cellulose ester molecule contained, for example, to change a humidity expansion coefficient. I think.

[Film thickness]

5-120 micrometers is preferable, as for the thickness of the optical film of this invention, 20-90 micrometers is more preferable, 30-80 micrometers is especially preferable. However, in the range which satisfy | fills said Formula (2), 5-80 micrometers is preferable, as for the thickness of a film, 10-60 micrometers is more preferable, and 15-50 micrometers may be more preferable. The latter preferable embodiment is preferably applicable in the case of a film having a relatively low total content of additives from the viewpoint of improving light unevenness and productivity. Moreover, when using as a polarizer protective film bonded to a liquid crystal panel, in order to improve the curvature of a panel, 5-80 micrometers is preferable, 15-65 micrometers is more preferable, It is especially preferable that it is 20-50 micrometers. Do. Moreover, if it exists in this range, the curvature of the panel accompanying a temperature-humidity change can be made small. In addition, when the thickness is too thin than the above-mentioned range, for example, handling property in a manufacturing process may deteriorate, or when the polarizing plate is exposed to a moist heat environment, minute wrinkles may occur on the surface of the polarizing plate, which is not preferable. When the thickness is too thick than the above-mentioned range, for example, a large amount of time is required for a drying time in the manufacturing process, or when the panel is exposed to a moist heat environment, the warpage may increase and light leakage may occur. Not desirable

[Hayes of film]

It is preferable that the haze of the optical film of this invention is small, and it is preferable that it is 0.01 to 2.0%. Or less, more preferably 1.0% or less, and further preferably 0.5% or less. However, even if haze value higher than these preferable ranges, since the haze of the film of this invention dominates the surface haze component which originates in surface shape, it adhere | attaches with a polarizing film using an adhesive agent, for example, If the surface shape is changed, it disappears and there is no influence on the display characteristics of the liquid crystal display device. The measurement of haze can be measured according to JIS K-6714 using a haze meter (HGM-2DP, Suga tester) etc. at 40 degreeC and 60% RH of 40 mm x 80 mm of the optical film sample of this invention.

[Board irregularities]

In this invention, linear unevenness | corrugation of a film shows linear unevenness extended in the film conveyance direction at the time of film forming in substantially parallel or substantially orthogonal direction. The number of linear irregularities represents a value calculated by visually reflecting or transmitting the film with the naked eye, and the number of counts is calculated as the number per 1000 mm section, and the height of the irregularities relates to each linear irregularities. An optical interference microscope (non-contact surface shape measuring instrument VertScan, Height measured using Ryoka Systems Co., Ltd.).

The linear irregularities are divided into three types: concave and / or convex, having a height of 3 to 30 nm, concave and / or convex, having a height exceeding 30 nm and 300 nm or less, and having a height exceeding 300 nm. Can be. Among them, the height of 3 to 30 nm is not visually recognized when the polarizing plate is bonded, but the number is not particularly limited in view of the appearance of the polarizing plate. However, when one or more is contained in the 100 mm section, the adhesion with the polarizing film is improved. Since the effect to be expected is anticipated, it is preferable, 1-50 individual is more preferable, and 3-10 individual are more preferable. The height exceeding 30 nm and 300 nm or less may be visually recognized by transmission observation even in a state where the polarizing plate is bonded, and the polarizing plate appearance and the display characteristics of the image display device may be deteriorated. It is preferable to have one or less, and it is especially preferable that it is substantially not contained. Moreover, since the height exceeding 300 nm adversely affects the external appearance of a film roll, it is preferable not to contain substantially.

[Spectroscopic characteristics, spectral transmittance]

The transmittance | permeability in wavelength 300-450 nm can be measured with the spectrophotometer "U-3210" {Hitachi Corporation} at 25 degreeC and 60% RH of the sample of 13 mm x 40 mm of an optical film. Inclined width can be calculated | required at 72% of wavelength -5% of wavelength. The limit wavelength can be represented by the wavelength of (inclined width / 2) + 5%, and the absorption edge can be represented by the wavelength of 0.4% of the transmittance. From this, the transmittance of 380 nm and 350 nm can be evaluated.

When using the optical film of this invention on the opposite side of the protective film which contacted the liquid crystal cell of a polarizing plate, the spectral transmittance in wavelength 380nm measured by the said method is 45% or more and 95% or less, and also wavelength 350 It is preferable that the spectral transmittance in nm is 10% or less.

[Glass transition temperature (Tg) and crystallization temperature (Tc)] [

In the present invention, the glass transition temperature (Tg) is the boundary temperature at which the mobility of the polymer constituting the web or film of the present invention changes greatly. In this invention, 20 mg of webs or a film is put into the sealed type measuring pan of a differential scanning calorimetry device (DSC), and this is heated up from -100 degreeC to 120 degreeC at 10 degreeC / min in nitrogen stream, and a baseline is a low temperature side. The temperature at which the knitting starts from is taken as Tg, and the start temperature of the exothermic peak observed in the process of increasing the temperature to 230 ° C is set to Tc.

[Equilibrium moisture content of film]

Although the water content (equilibrium water content) of the optical film of the present invention is not particularly limited, in order to avoid impairing the adhesion to water-soluble polymers such as polyvinyl alcohol when used as a protective film of the polarizing plate, regardless of the film thickness, 25 It is preferable that the moisture content in 80 degreeC and 80% RH is 0.1-6 mass%. It is more preferable that it is 1-4.5 mass%, and it is especially preferable that it is 2-4 mass%. When equilibrium moisture content is 6 mass% or less, when using as a support body of retardation film, since the dependence by the humidity change of retardation does not become large too much, it is preferable.

The measurement method of the moisture content measured 7 mm x 35 mm of the optical film sample of this invention with the Karl Fischer method by the moisture meter, sample drying apparatus "CA-03", and "VA-05" (all are the Mitsubishi Chemical Corporation make). The water content (g) was calculated by dividing the sample mass (g).

[Water vapor permeability of film]

The water vapor transmission rate of a film is measured on 40 degreeC and the conditions of 90% RH based on JISZ-0208. Although the water vapor transmission rate of the optical film of this invention is not specifically limited, It is preferable that it is 50-1500 g / m <2> * 24h. It is more preferable that it is 100-1000 g / m <2> * 24h, and it is especially preferable that it is 200-800 g / m <2> * 24h. When the moisture permeability is within this range, both the polarizing plate workability and the durability of the polarizing plate against humidity or moist heat can be satisfied, which is preferable.

[Sound wave propagation velocity (sound velocity)]

In the present invention, the direction in which the sound wave propagation speed is maximized is obtained by using an orientation measuring instrument (SST-2500: Nomura Corporation Co., Ltd.) after humidifying the film for 24 hours at 25 ° C. and 60% relative humidity. It calculated | required as the direction which propagates the longitudinal wave vibration maximum. In the present invention, the direction in which the elastic modulus is maximum and the direction in which the sound wave propagation speed is maximum can be considered to be substantially parallel.

[Photoelastic coefficient]

When using the optical film of this invention as a polarizing plate protective film, birefringence (Re, Rth) may change by stress etc. by shrinkage of a polarizer. The change in birefringence caused by the stress is the same, but can be measured as the photoelastic coefficient, the range is 15 × 10 ^-12 Pa ^-1 or less is preferable (15 Br or less) ^{and, -5 × 10 - l2 Pa -l} ~ 12 × 10 ^-12 Pa ^{- 1,} and more ^{preferably, -2 × 10 -12 Pa -1 ~} 11 × 10 -12 Pa - more preferably ^1.

[Contact angle of film surface by alkali saponification treatment]

Since the optical film of this invention contains cellulose acylate, alkali saponification treatment is mentioned as one of the effective means of the surface treatment at the time of using as a polarizing plate protective film. In this case, it is preferable that the contact angle of the film surface after alkali saponification process is 55 degrees or less. More preferably, it is 50 degrees or less, and it is still more preferable that it is 45 degrees or less.

[Surface treatment]

By performing the surface treatment as occasion demands, the optical film can be improved in adhesion between the optical film and each functional layer (for example, the undercoat layer and the back layer). For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment herein may be a low temperature plasma generated under a low pressure gas of 10 ⁻³ to 20 Torr, and further preferably a plasma treatment under atmospheric pressure. Plasma-excited gas means a plasma-excited gas under the above-mentioned conditions, and examples thereof include argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, fluorine such as tetrafluoromethane and mixtures thereof. These details are described in detail in pages 30 to 32 of the Invention Association Publication (Publication No. 2001-1745, issued March 15, 2001, Invention Association), and can be preferably used in the present invention. .

[Functional layer]

The optical film of this invention is applied to an optical use and a photosensitive material as the use, for example. It is preferable that especially an optical use is a liquid crystal display device, The liquid crystal cell in which a liquid crystal display device carries a liquid crystal between two electrode substrates, two polarizing elements arrange | positioned at both sides, this liquid crystal cell, and its polarizing element It is more preferable that it is the structure which arrange | positioned at least 1 optical compensation sheet in between. As these liquid crystal display devices, TN, IPS, FLC, AFLC, OCB, STN, ECB, VA and HAN are preferable.

In that case, when using the optical film of this invention for the above-mentioned optical uses, providing various functional layers is performed. They are antistatic layer, cured resin layer (transparent hard coat layer), antireflection layer, an easily bonding layer, an anti-glare layer, an optical compensation layer, an orientation layer, a liquid crystal layer, etc., for example. These functional layers and materials thereof include surfactants, slippers, matting agents, antistatic layers, hard coat layers, and the like, and are disclosed in the Invention Association Publication (Air No. 2001-1745, issued March 15, 2001). Association), which is described in detail on pages 32 to 45, and can be preferably used in the present invention.

<< Phase difference film >>

The retardation film of this invention contains at least 1 optical film of this invention.

Moreover, the optical film of this invention can be used as retardation film. In addition, a "phase difference film" generally means an optical material which is used for display apparatuses, such as a liquid crystal display device, and has optical anisotropy, and has the same meaning as a retardation plate, an optical compensation film, an optical compensation sheet, etc. In a liquid crystal display device, a retardation film is used for the purpose of improving the contrast of a display screen, or improving viewing angle characteristic and color taste.

By using the optical film of this invention, retardation is freely controlled and the retardation film excellent in adhesiveness with a polarizing film can be manufactured.

Moreover, it is also possible to laminate | stack a plurality of optical films of this invention, or to laminate | stack the optical film of this invention and films other than this invention, and to adjust Re and Rth suitably, and to use as retardation film. Lamination | stacking of a film can be performed using an adhesive or an adhesive agent.

Moreover, depending on the case, the optical film of this invention can be used as a support body of retardation film, the optical anisotropic layer which consists of a liquid crystal etc. can be formed on it, and can also be used as retardation film. The optically anisotropic layer to be applied to the retardation film of the present invention may be formed of, for example, a composition containing a liquid crystalline compound, a polymer film having birefringence, or an optical film of the present invention.

As said liquid crystalline compound, a discotic liquid crystalline compound or a rod-like liquid crystalline compound is preferable.

[Discotic liquid crystalline compound]

Examples of discotic liquid crystalline compounds which can be used as the liquid crystalline compounds in the present invention include various documents (for example, C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111). (1981): Japanese Chemical Sculpture, Quarterly Chemistry Summary, No. 22, Chemistry of Liquid Crystals, Chapter 5, Chapter 10, Section 2 (1994); B. Kohne et al., Angew.Chem.Soc.Chem. Comm., Page 1794 (1985); J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page 2655 (1994)).

In the optically anisotropic layer, the discotic liquid crystalline molecules are preferably fixed in an alignment state, and most preferably, are fixed by a polymerization reaction. The polymerization of discotic liquid crystal molecules is described in JP-A-8-27284. In order to fix a discotic liquid crystalline molecule by superposition | polymerization, it is necessary to couple a polymeric group as a substituent to the disk-shaped core of a discotic liquid crystalline molecule. However, when a polymeric group is directly connected to a disk-shaped core, it becomes difficult to maintain an orientation state in a polymerization reaction. Thus, a linking group is introduced between the discotic core and the polymerizable group. Discotic liquid crystalline molecules having a polymerizable group are disclosed in Japanese Patent Laid-Open No. 2001-4387.

[Rod-shaped liquid crystalline compound]

Examples of the rod-like liquid crystalline compound which can be used as the liquid crystalline compound in the present invention include azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, Cyanophenylcyclohexane, cyano substituted phenylpyrimidines, alkoxy substituted phenylpyrimidines, phenyldioxane, tolans and alkenylcyclohexylbenzonitriles. Moreover, as said rod-like liquid crystalline compound, not only the low molecular liquid crystalline compound mentioned above but a polymeric liquid crystalline compound can also be used.

In the optically anisotropic layer, the rod-like liquid crystalline molecules are preferably fixed in an aligned state, and most preferably fixed by a polymerization reaction. Examples of the polymerizable rod-like liquid crystalline compound usable in the present invention include, for example, Makromol. Chem., 190, page 2255 (1989), Advanced Materials 5, page 107 (1993), US Pat. No. 4,683,327, US Pat. No. 5,622,648, US Pat. No. 5,770,107, International Publication 95 / 22586 pamphlet, international publication 95/24455 pamphlet, international publication 97/00600 pamphlet, international publication 98/23580 pamphlet, international publication 98/52905 pamphlet, Japanese Unexamined-Japanese-Patent No. 1-272551 , JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, JP-A-2001-328973 and the like.

<< polarizing plate >>

The polarizing plate of this invention contains at least 1 optical film of this invention or retardation film of this invention.

The optical film or retardation film of this invention can be used as a protective film of a polarizing plate (polarizing plate of this invention). The polarizing plate of this invention consists of a polarizing film and two polarizing plate protective films (optical films) which protect both surfaces, and it is especially preferable to use the optical film or retardation film of this invention as at least one polarizing plate protective film.

When using the optical film of this invention as the said polarizing plate protective film, the said optical film of this invention is given the said surface treatment (it also describes Unexamined-Japanese-Patent No. 6-94915, Unexamined-Japanese-Patent No. 6-118232), It is preferable to make it hydrophilic, for example, it is preferable to perform a glow discharge process, a corona discharge process, or an alkali saponification process. As the surface treatment, an alkali saponification treatment is most preferably used.

As the polarizing film, for example, a polyvinyl alcohol film immersed in an iodine solution and stretched can be used. When a polarizing film obtained by immersing a polyvinyl alcohol film in an iodine solution and stretching it is used, the surface-treated surface of the optical film of the present invention can be directly bonded to both surfaces of the polarizing film by using an adhesive. In the production method of the present invention, it is preferable that the optical film is directly bonded to the polarizing film. As the adhesive, an aqueous solution of polyvinyl alcohol or polyvinyl acetal (for example, polyvinyl butyral) or latex of a vinyl polymer (for example, polybutyl acrylate) can be used. Particularly preferred adhesives are aqueous solutions of fully saponified polyvinyl alcohol.

Generally, since a liquid crystal cell is formed between two polarizing plates, a liquid crystal display device has four polarizing plate protective films. Although the optical film of this invention may be used for any of four polarizing plate protective films, the optical film of this invention is especially glass as a protective film arrange | positioned between the polarizing film and liquid crystal layer (liquid crystal cell) in a liquid crystal display device. Can be used. In addition, a transparent hard coat layer, an antiglare layer, an antireflection layer, and the like can be formed on the protective film disposed on the opposite side of the optical film of the present invention with the polarizing film interposed therebetween. In particular, It is preferably used as a protective film.

A polarizing plate is comprised by the polarizer and the protective film which protects both surfaces, Moreover, it is comprised by bonding a protective film to one surface of this polarizing plate, and a separate film to the opposite surface. A protective film and a separate film are used for the purpose of protecting a polarizing plate at the time of polarizing plate shipment, a product inspection, etc. In this case, a protective film is bonded for the purpose of protecting the surface of a polarizing plate, and is used for the opposite surface side of the surface which bonds a polarizing plate to a liquid crystal plate. In addition, a separate film is used for the purpose of covering the contact bonding layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

In a liquid crystal display device, a substrate including a liquid crystal is usually disposed between two polarizing plates. However, the polarizing plate protective film to which the optical film of the present invention is applied has excellent display properties even if it is disposed at any position. In particular, since a transparent hard coat layer, an antiglare layer, an antireflection layer, etc. are formed in the polarizing plate protective film of the display side outermost surface of a liquid crystal display device, it is especially preferable to use this polarizing plate protective film for this part.

<< liquid crystal display device >>

The optical film, retardation film, and polarizing plate of this invention can be used for the liquid crystal display device of various display modes. Each liquid crystal mode in which these films are used will be described below. Among these modes, although the optical film, retardation film, and polarizing plate of this invention can be used suitably in all modes, it is especially used for the liquid crystal display device of VA mode and IPS mode. These liquid crystal display devices may be either transmissive, reflective or transflective.

(TN type liquid crystal display device)

The optical film of this invention is used suitably as a support body of the retardation film of the TN type liquid crystal display device which has a liquid crystal cell of TN mode. The TN mode liquid crystal cell and the TN type liquid crystal display device are well known from the past. About retardation film used for a TN type liquid crystal display device, Unexamined-Japanese-Patent No. 3-9325, Unexamined-Japanese-Patent No. 6-148429, Unexamined-Japanese-Patent No. 8-50206, and Unexamined-Japanese-Patent No. 9- In addition to the publications of 26572, Mori et al. (Jpn. J. Appl. Phys. Vo 1.36 (1997) p. 143 or Jpn. J. Appl. Phys. Vo 1.36 (1997) p. 1068 ) Is described.

(STN type liquid crystal display device)

The optical film of the present invention may be used as a support of a retardation film of an STN type liquid crystal display device having a liquid crystal cell of STN mode. Generally in STN type liquid crystal display devices, the rod-like liquid crystalline molecules in the liquid crystal cell are twisted in the range of 90 to 360 degrees, and the product (Δnd) of the refractive index anisotropy (Δn) and the cell gap (d) of the rod-shaped liquid crystalline molecules is 300. It is in the range of-1500 nm. Japanese Patent Laid-Open Publication No. 2000-105316 discloses a retardation film used in an STN type liquid crystal display device.

(VA type liquid crystal display device)

The optical film of this invention is used especially advantageously as a support body of the retardation film and retardation film of VA type liquid crystal display device which has a liquid crystal cell of VA mode. The VA type liquid crystal display device may be an orientation-divided system as described, for example, in JP-A-10-123576. In these aspects, the polarizing plate using the optical film of the present invention contributes to enlarged viewing angle and quantity of contrast.

(IPS type liquid crystal display device and ECB type liquid crystal display device)

The optical film of this invention is used especially advantageously as a protective film of the retardation film, the support body of retardation film, or polarizing plate of IPS type liquid crystal display device and ECB type liquid crystal display device which have a liquid crystal cell of IPS mode and ECB mode. These modes are a mode in which the liquid crystal material is oriented in a substantially parallel manner during black display, and a liquid crystal molecule is aligned in parallel with the substrate surface in a voltage unapplied state to perform black display. In these aspects, the polarizing plate using the optical film of the present invention contributes to enlarged viewing angle and quantification of contrast.

Moreover, although | Rth | <25nm is preferable, in the area of 450-650 nm, it is especially preferable that the change of color taste is small, and that Rth is 0 nm or less.

In this aspect, using the polarizing plate using the optical film of this invention for the protective film (protective film of a cell side) arrange | positioned between a liquid crystal cell and a polarizing plate among the protective films of the said polarizing plate up and down of a liquid crystal cell above and below a liquid crystal cell. desirable. Moreover, More preferably, it is preferable to arrange | position the optically anisotropic layer which set the value of the retardation of the optically anisotropic layer to 2 times or less of the value of (DELTA) n * d of a liquid crystal layer between the protective film of a polarizing plate, and a liquid crystal cell on one side. Do.

(OCB type liquid crystal display device and HAN type liquid crystal display device)

The optical film of this invention is advantageously used also as a support body of the retardation film of the OCB type liquid crystal display device which has a liquid crystal cell of OCB mode, or the HAN type liquid crystal display device which has a liquid crystal cell of HAN mode. In the retardation film used for an OCB type liquid crystal display device or an HAN type liquid crystal display device, it is preferable that the direction which the absolute value of retardation becomes minimum does not exist in the surface of a retardation film nor a normal direction. The optical properties of the retardation film used for the OCB type liquid crystal display device or the HAN type liquid crystal display device are also determined by the optical properties of the optically anisotropic layer, the optical properties of the support, and the arrangement of the optically anisotropic layer and the support. The retardation film used for an OCB type liquid crystal display device or an HAN type liquid crystal display device is described in Unexamined-Japanese-Patent No. 9-197397. Mori et al. (Jpn. J. Appl. Phys. Vol. 38 (1999) p. 2837).

(Reflective liquid crystal display)

The optical film of this invention is advantageously used also as a retardation film of a TN type, STN type, HAN type, and GH (Guest-Host) type reflection type liquid crystal display device. These display modes are well known from the example. The TN type reflection type liquid crystal display device is described in Japanese Patent Laid-Open Publication No. 10-123478, International Publication No. 98/48320, and Japanese Patent Publication No. 3022477. The retardation film used in the reflection type liquid crystal display device is described in WO 00/65384.

(Other liquid crystal display device)

The optical film of this invention is advantageously used also as a support body of the retardation film of the ASM type liquid crystal display device which has a liquid crystal cell of ASM (Axially Symmetric Aligned Microcell) mode. The liquid crystal cell of ASM mode has the characteristic that the thickness of the cell is hold | maintained by the resin spacer which can be adjusted. The other property is the same as that of the liquid crystal cell of TN mode. A liquid crystal cell of the ASM mode and an ASM type liquid crystal display are described in Kume et al., SID 98 Digest 1089 (1998).

Moreover, the optical film of this invention can also be used as a retardation film used preferably in the video display panel which can display 3D stereoscopic image display, or a support body of retardation film. Specifically, (lambda) / 4 layer can be formed in the whole surface of the optical film of this invention, or a patterned retardation layer from which birefringence differs can be formed alternately on a line, for example. The optical film of the present invention can be suitably used in the latter, in particular, because it has a smaller dimensional change ratio with respect to humidity change than a conventional cellulose acylate film.

(Hard coat film, antiglare film, antireflection film)

The optical film of this invention can be applied to a hard-coat film, an anti-glare film, and an antireflection film. For the purpose of improving the visibility of flat panel displays such as LCD, PDP, CRT, EL, etc., one or both of a hard coat layer, an antiglare layer, and an antireflection layer can be provided on one or both surfaces of the optical film of the present invention. Preferred embodiments as such an antiglare film and an antireflection film are described in detail in pages 54 to 57 of the Invention Association Publication (Publication No. 2001-1745, issued March 15, 2001, Invention Association). The optical film of the invention can be preferably used.

(Transparent substrate)

The optical film of the present invention may make optical anisotropy close to zero, has excellent transparency, and has a small retardation change even when kept in a moist heat environment, so that the liquid crystal cell glass substrate of the liquid crystal display device, that is, the driving liquid crystal It can also be used as a transparent substrate encapsulating the.

Since the transparent substrate which encloses a liquid crystal needs to be excellent in gas barrier property, you may provide a gas barrier layer on the surface of the optical film of this invention as needed. The form and material of the gas barrier layer is not particularly limited, and depositing SiO ₂ or the like at least one side of the optical film of the present invention, or of a vinylidene chloride polymer or a vinyl alcohol-based polymer, such as relatively high gas barrier polymer A method of forming a coat layer or laminating these inorganic layers and organic layers can be considered, and these can be used suitably.

Moreover, in order to use as a transparent substrate which encloses a liquid crystal, you may form the transparent electrode for driving a liquid crystal by voltage application. The transparent electrode is not particularly limited, but a transparent electrode can be formed by laminating a metal film, a metal oxide film, or the like on at least one surface of the optical film of the present invention. Especially, a metal oxide film is preferable at the point of transparency, electroconductivity, and a mechanical characteristic, Especially, the thin film of indium oxide containing 2-15% of zinc oxide mainly using tin oxide can be used preferably. Details of these techniques are disclosed in, for example, Japanese Patent Laid-Open No. 2001-125079, Japanese Patent Laid-Open No. 2000-227603, and the like.

Example

The features of the present invention will be described in more detail with reference to the following Examples. The materials, amounts, ratios, processing contents, processing procedures and the like shown in the following examples can be appropriately changed as long as they do not depart from the gist of the present invention. Accordingly, the scope of the present invention should not be construed as being limited by the following specific examples.

<Measurement >>

First, the measuring method and the evaluation method of the characteristics are shown below.

[Degree of substitution]

Acyl substitution degree of a cellulose acylate is Carbohydr. Res. By the method described in 273 (1995) 83-91 (Tezuka, etc.) were determined by ¹³ C-NMR.

[Board irregularities]

1000 mm of samples were cut out from the produced film in the full width and conveyance direction, parallel light was irradiated to the film, the transmitted image was reflected on the screen, and the number of linear irregularities was visually counted. The height of the obtained linear unevenness | corrugation was measured by the method mentioned above, and the number of linear unevenness | corrugation was classified for every height, and it showed in Table 1.

[Retardation]

5 points in the width direction of the film (the center of the film, the ends (positions of 5% of the total width respectively from both ends), and two points of the middle part of the center and the end) were sampled every 100 m in the longitudinal direction, and 5 A sample of cm × 5 cm size was taken out, and the average value of each point evaluated according to the method described above was calculated, and Re, Rth, and ΔRth were calculated, respectively.

[Photoelastic coefficient]

A 1 cm × 5 cm sample was cut out from the prepared optical film, and a retardation value in the film plane was measured while applying a stress to the sample at 25 ° C. using a spectroscopic ellipsometer (M-220, manufactured by Nippon Spectroscopy). And it computed from the inclination of the relationship of retardation value and a stress.

[Elasticity rate]

Using a universal tension tester "STM T50BP" manufactured by Toyo Baldwin Co., Ltd., the stress at 0.1% elongation and 0.5% elongation was measured at a tensile rate of 10% / min in a 25 ° C and 60 RH% atmosphere, and from the slope Elastic modulus was calculated | required. In addition, the measurement was performed about arbitrary 2 directions orthogonal, respectively, and the rising average of them is shown in Table 1.

[Water content]

7 mm x 35 mm sample was cut out from the manufactured optical film, and after 24 hours-humidification at 25 degreeC and 60% of a relative humidity, moisture meter, a sample drying apparatus, "CA-03" and "VA-05" {both Mitsubishi Chemical Moisture content was measured by the Karl Fischer method.

<< 1 >> Preparation and Evaluation of Optical Film

The optical film of this invention selected and manufactured the thing of Table 1 from the material and manufacturing method shown below.

<< material >> to use for filmmaking

1] cellulose acylate

The thing of Table 1 was selected from the following cellulose acylate. Each cellulose acylate was heated to 120 ° C and dried, and the water content was 0.5 mass% or less, and then 20 parts by mass was used.

Cellulose acylate A:

A powder of cellulose acetate having a degree of substitution of 2.86 was used. The cellulose acylate A had a viscosity average degree of polymerization of 300, an acetyl group substitution degree at the 6 position of 0.89, an acetone extract content of 7% by mass, a mass average molecular weight / number average molecular weight ratio of 2.3, a water content of 0.2% Methane solution had a viscosity of 305 mPa.s, a residual amount of acetic acid of 0.1 mass% or less, a Ca content of 65 ppm, an Mg content of 26 ppm, an iron content of 0.8 ppm, a sulfuric acid ion content of 18 ppm, a yellow index of 1.9, The amount of acetic acid was 47 ppm. The average particle size of the powder was 1.5 mm and the standard deviation was 0.5 mm.

Cellulose Acylate B:

The powder of cellulose acetate whose substitution degree is 2.92 and the viscosity average degree of polymerization is 290 and the acetyl group substitution degree of 0.96 position was used.

Cellulose acylate C:

The powder of the cellulose acetate whose substitution degree is 2.86 and the viscosity average degree of polymerization is 350 and the acetyl group substitution degree of 0.89 in 6-position was used.

Cellulose acylate D:

20 mass parts of cellulose acetate propionate powder derived from a linter having an acetyl substitution degree of 1.90, a propionyl substitution degree of 0.90, and a viscosity average degree of polymerization of 270.

2] solvent

The following solvent A or B 80 parts by mass was used. The water content of each solvent was 0.2 mass% or less.

Solvent A dichloromethane / methanol / butanol = 81/18/1 (mass ratio)

Solvent B dichloromethane / methanol = 85/15 (mass ratio)

3] additive

Among the following additive groups, those listed in Table 1 were selected. However, in Table 1, "mass part" of each additive shows the mass part at the time of making cellulose acylate 100 mass parts.

(A compound having a repeating unit)

A-1: condensate of ethanediol / adipic acid (1/1 molar ratio), number average molecular weight 1000, hydroxyl value 112 mgKOH / g

A-2: Acetic ester body of both ends of condensate of ethanediol / 1,2-propanediol / adipic acid (7/3/10 molar ratio), a number average molecular weight 1000, and a hydroxyl value are 0 mgKOH / g

(Thickener)

G: the compound of the following structure.

(35)

(Retardation adjustment agent)

(36)

L: a compound having the structure

(Made by Matt)

M1:

Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.02 parts by mass)

M2:

Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.15 parts by mass)

4] melting

The above solvent and additives were added to a 4000 liter stainless steel dissolution tank having a stirring blade, and the cellulose acylate was gradually added while stirring and dispersing. After completion of the addition, the mixture was stirred at room temperature for 2 hours, swelled for 3 hours and then stirred again to obtain a cellulose acylate solution.

In addition, for the stirring, an eccentric stirring shaft and a central shaft of a dissolver type which are stirred at a circumferential speed of 5 m / sec (shear stress 5 × 10 ⁴ kgf / m / sec ² [4.9 × 10 ⁵ N / m / sec ² ]) to have an anchor blade was used for agitation by stirring shaft peripheral speed of 1 m / sec (shear stress ^{1 × 10 4 ㎏f / m /} sec 2 [9.8 × 10 4 N / m / sec 2]). Swelling was performed by stopping a high speed stirring shaft and making the circumferential speed of the stirring shaft which has an anchor blade into 0.5 m / sec.

The swollen solution was heated to 50 ° C. from the tank to a pipe with a jacket, and further heated to 90 ° C. by 1.2 MPa pressurization to completely dissolve it. The heating time was 15 minutes. At this time, the filter, housing | casing, and piping which were exposed to high temperature used what was excellent in Hastelloy alloy (trademark) zero corrosion resistance, and used the thing which has the jacket which distribute | circulates the fruit for heat insulation.

Next, the temperature was lowered to 36 캜 to obtain a cellulose acylate solution.

The condensation dope thus obtained was flashed in an atmospheric pressure tank at 80 DEG C, and the evaporated solvent was recovered by a condenser. The solid concentration of the dope after flashing was 24.8 mass%. In addition, the condensed solvent is returned to the recovery process (the recovery is performed by the distillation process and the dehydration process) in order to be reused as a solvent in the preparation process. In the flash tank, it stirred and defoamed by rotating the shaft which has an anchor vane in a center axis | shaft at a circumferential speed of 0.5 m / sec. The temperature of the dope in a tank was 25 degreeC, and the average residence time in a tank was 50 minutes.

5] Filtration

Next, a sintered fiber metal filter having an initial nominal pore diameter of 10 µm was passed through, followed by passing a 10 µm sintered fiber filter in the same manner. The dope temperature after filtration was adjusted to 36 degreeC, and it stored in the 2000 L stainless steel stock tank.

(Production A of Film)

In the following table, films 1-18 were manufactured by (Manufacture A of film) using the solvent A mentioned above.

1] flexible process

Subsequently, the dope in the stock tank was fed. The casting die was equipped with a feed block having a width of 2.1 m and adjusted for common lead, and was used to form a three-layer film by laminating on both sides in addition to the mainstream. In the following description, the layer formed from the mainstream is called an intermediate | middle layer, the layer of a support surface side is called a support surface, and the surface on the opposite side is called an air surface. In addition, the dope liquid supply flow path used three flow paths for an intermediate | middle layer, a support surface, and an air surface, and each solid content concentration was adjusted by adding a solvent, or raising and adding a solution with a high solid content concentration, and adjusting it suitably. . In addition, in manufacture of the film in which the item of a "support surface" and an "air surface" is described as "-" in the following table | surface, the die for co-combustion is not used but the film forming is carried out using the die for flexible in a single layer. Was carried out.

Then, the casting width was adjusted to be 2000 mm and the clearance in the direction orthogonal to it was appropriately adjusted within the range of 0.2 to 1.5 mm in Example 1, and the liquid feeding pressure to the die was adjusted so as to be the values shown in Table 1 to perform the casting. It was. In order to adjust the temperature of dope to 29 degreeC, the inlet temperature of the heat transfer medium which forms a jacket in the casting die | dye and supplies in a jacket was 29 degreeC.

All die, feed block and piping were kept at 29 ℃ during the working process.

2) flexible die

The die is made of a two-phase stainless steel having a mixed composition of austenite and ferrite phases, and has a coefficient of thermal expansion of 2 × 10 ⁻⁶ (° C. ⁻¹ ) or less, and is approximately equivalent to SUS316 in a forced corrosion test in an aqueous electrolyte solution. Corrosive materials were used. The finishing precision of the liquid contact surface of a casting die and a feed block was 1 micrometer or less in surface roughness.

In addition, what formed the WC coating by the thermal spraying method was used for the lip | tip tip of a casting die. Further, a mixed solvent (dichloromethane / methanol / butanol (83/15/2 parts by mass)) as a solvent for solubilizing the dope was supplied to the gas-liquid interface between the bead end and the slit at 0.5 ml / min on one side.

3) metal support

The dope extruded from the die was a mirror-polished stainless steel support having a width of 2.1 m and a diameter of 3 m as a support. The surface was nickel plated and hard chrome plated. The surface roughness of the drum was polished to 0.01 μm or less, and a support having no pinholes of 50 μm or more at all, and having pinholes of 10 μm to 50 μm and pinholes of 10 μm or less at 2 / m 2 or less was used. At this time, the temperature of the drum was set to -5 ° C, and the rotation speed of the drum was set so that the drum's main speed was 80 m / min. Further, when the surface of the drum was contaminated with the softening, cleaning was properly performed.

4) flexible drying

Subsequently, the dope which was cast, cooled, and gelled on the drum disposed in the space set at 15 ° C. was peeled off as a gelling film (web) at the point of rotation of 320 ° on the drum. At this time, the peeling rate was set to 106% with respect to the support body speed.

5) Tenter conveying and drying process conditions

The peeled web was conveyed in a drying zone, fixing both ends with the tenter which has a pin clip, and it dried by the drying wind.

6) Post-drying process conditions

The polymer film obtained by the above method was further dried in a roller conveying zone. The roller was made of aluminum or carbon steel, and the surface was hard chrome plated. The surface shape of the roller used the thing flat and the thing matted by blasting.

7) Post-treatment, winding condition

The polymer film after drying was cooled to 30 degrees C or less, and both edges were cut | disconnected. In the edge cutting, two devices for slitting the film end portion were provided on both left and right ends of the film (the number of slit devices per side was 2), and the end portion of the film was slit. Both ends of the film were knurled. Knurling was provided by embossing from one side. In this way, the film with a final product width of 1400 mm was obtained and wound up by the winding machine.

The winding chamber was kept at a room temperature of 25 ° C. and a humidity of 60%. The diameter of the winding core was 169 mm, the winding start tension was 200 N / width, the winding end was set to the tension pattern which became 175 N / width, and the winding length was set as the roll shape of 3900 m. At this time, the external appearance of the roll was inspected and shown in Table 1 as "right after the external appearance of roll." In addition, the roll was stored in 25 degreeC and the storage rack of 55% of a relative humidity for 1 month, the same test | inspection was performed, and the result was shown in Table 1 as "roll appearance time progress."

(Roll appearance)

The roll appearance was inspected and the following references | standards evaluated.

A: Loosely wound, no wrinkles

B: Slightly loosely wound, glued or wrinkled on the ends, but no practical problem

C: Slightly loose wound, adhesion or wrinkles are confirmed, but practically no problem

D: Loosely wound, adhered to, or wrinkled, and cannot be applied as an optical film.

In addition, after film formation, the peeling residual of the cast film formed from dope was not observed at all on the drum which is a metal support body.

(Production B of Film)

In the manufacture of the films 1 and 2, the films 21 and 22 were produced in the same manner as the films 1 and 2, except that the solvent A was changed from the solvent A to the solvent B, and the film forming method was changed to the following method. A film equivalent to 2 was obtained.

1) Flexible process

The dope in the stock tank was fed. The flexible die was equipped with a feed block having a width of 1.8 m and adjusted for shared lead, and was used to form a three-layer film by laminating on both sides in addition to the mainstream. Three flow paths for an intermediate layer, a support surface, and an air surface were used for the dope feeding flow path, and each solid content density | concentration was reduced by adding a solvent, or the solution of a high solid content concentration was raised and adjusted suitably.

The flow rate of the dope of the die protrusion was adjusted by setting the casting width to 1700 mm, and casting was performed. In order to adjust the temperature of dope to 29 degreeC, the inlet temperature of the heat transfer medium which forms a jacket in the casting die | dye and supplies in a jacket was 29 degreeC.

All die, feed block and piping were kept at 29 ℃ during the working process.

2) flexible die

The die is made of a two-phase stainless steel having a mixed composition of austenite and ferrite phases, and has a coefficient of thermal expansion of 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less, and is approximately equivalent to SUS316 in a forced corrosion test in an aqueous electrolyte solution. Corrosive materials were used. The finishing precision of the liquid contact surface of a casting die and a feed block was 1 micrometer or less in surface roughness.

In addition, what formed the WC coating by the thermal spraying method was used for the lip | tip tip of a casting die. Moreover, the mixed solvent (dichloromethane / methanol (87/13 mass part)) which is a solvent which solubilizes dope was supplied at 0.5 ml / min from the one side to the gas-liquid interface of a bead edge part and a slit.

3) metal support

The dope extruded from the die covalently flamed three layers of dope from the die using an endless band made of stainless steel having a width of 2.1 m and a length of 70 m as a support. The drum of a flexible part used what has the installation which circulates a heat transfer medium (refrigerant) inside to cool a support body. In addition, since the other drum supplies heat for drying, the heat transfer medium can pass through. The temperature of each heat transfer medium was set at 5 ° C (flexible die side) and 40 ° C. The surface temperature of the support center part immediately before casting was l5 degreeC. The temperature difference at both ends was 6 ° C or less.

4) flexible drying

The temperature of the flexible chamber in which the flexible die and the support were formed was maintained at 35 占 폚. The dope cast on the band first sent the drying wind of parallel flow, and was dried. The temperature of the drying wind made 135 degreeC the upstream of the upper band, and 140 degreeC of the downstream. Moreover, the lower band part was 65 degreeC.

For 5 seconds after the casting, the wind blowing device prevented the dry wind from directly contacting the dope and peeled off as a film from the flexible support when the solvent ratio in the dope became 150% by mass on a dry basis. The peeling speed (peel roll draw) was set so that it may peel suitably in 100.1%-105% of range with respect to the support body speed at this time. Moreover, the surface temperature of the peeled film was 15 degreeC.

The peeled film was conveyed to the moving part in which the many rollers are formed. The moving part was provided with three rollers, and the temperature of the moving part was maintained at 40 degreeC.

5) Tenter conveying and drying process conditions

The peeled film was conveyed in the drying zone of a tenter, fixing both ends with the tenter which has a clip, and it dried by the drying wind. The tenter was divided into four zones (stretching zone, axial width zone, heating zone, cooling zone), and the drying wind temperature of each zone was able to be controlled independently. Stretching and axial width were also performed in the width direction, conveying in a tenter.

And after edge cutting process, it carried out similarly to (Manufacture A of film), and wound up in roll shape of 3900m.

6) Post-drying process conditions

It carried out similarly to (Manufacture A of film).

7) Post-treatment, winding condition

It carried out similarly to (Manufacture A of film), and evaluated the roll.

(Production C of Film)

In the production of the film 1, a film 31 was produced in the same manner as in the film 1 except for changing from cellulose acylate A to cellulose acylate D and without using the solvent A and changing the film forming method to the following method. As a result, a film having a film equivalent to that of Film 1 was obtained except that ΔRth was 8 nm, the water content was 2.1 wt%, and the elastic modulus was 3.3 GPa.

1) Preparation of Pellets

After drying a cellulose acylate with a 90 degreeC vacuum dryer and making water content 0.03% or less, 0.3 mass% of said additives and stabilizer (Irganox 1010 (made by Chiba-Geigi Co., Ltd.)) are added, and nitrogen is 230 degreeC. In the airflow, it extruded in water using the twin-screw kneading extruder with a vent, and made it into strand shape, and it cut and obtained the pellet of diameter 3mm length 5mm.

2) melt film forming

The obtained pellets were dried in a vacuum dryer at 90 ° C. to have a water content of 0.03% or less, and then kneaded and extruded at a feed section 210 ° C., a compression section 230 ° C. and a metering section 230 ° C. using a single screw kneading extruder. At this time, a 300 mesh screen filter, a gear pump, and a leaf disk filter having a filtration accuracy of 7 µm were disposed in this order between the extruder and the die, and these were connected by melt piping. In addition, the static mixer was installed in the melt pipe immediately before the die, and extruded from the hanger coat die while adjusting the temperature difference between the die ends and the center temperature of the die, the temperature difference between the die lip temperature and the die temperature, and the C / T ratio.

Thereafter, melt (molten resin) was extruded on three cast rolls. At this time, the touch roll was made to contact the cast roll (chill roll) of the most upstream. The touch roll used what was described in Example 1 of Unexamined-Japanese-Patent No. 11-235747 (it has a base material with a double suppression roll, but the thickness of the thin metal outer cylinder was 2 mm). In addition, the temperature of the series of three cast rolls containing a chill roll was touch roll temperature +3 degreeC, touch roll temperature -2 degreeC, and touch roll temperature -7 degreeC in order from an upstream.

And after edge cutting process, it carried out similarly to (Manufacture A of film), and wound up in roll shape of 3900m.

<< 2 >> Manufacturing and evaluation of a polarizing plate

(Production of polarizing plate)

1] saponification of film

After immersing each film prepared in the Examples and Comparative Examples and Fuji-Tack TD60UL (manufactured by Fuji Film Co., Ltd.) at 37 ° C. in a 4.5 mol / L sodium hydroxide aqueous solution (saponifying solution) for 1 minute, The film was washed with water and then immersed in 0.05 mol / L sulfuric acid aqueous solution for 30 seconds, and then further washed with water. And water removal by the air knife was repeated 3 times, and after removing water, it was made to dry for 15 second in the 70 degreeC dry zone, and the saponified film was produced.

2] Preparation of Polarizing Film

According to Example 1 of Unexamined-Japanese-Patent No. 2001-141926, the peripheral speed difference was provided between two pairs of nip rolls, it extended | stretched in the longitudinal direction, and prepared the polarizing film of 20 micrometers in thickness.

3] bonding

After selecting two pieces from the polarizing film obtained in this way and the said saponified film, and inserting the said polarizing film between them, PVA (Kuraray Co., Ltd. product, PVA-117H) 3% aqueous solution was used as an adhesive agent. It bonded together by the roll-to-roll so that the polarization axis and the longitudinal direction of a film may orthogonally cross, and manufactured the polarizing plate. Here, one film of a polarizing film was made into the film which saponified one piece selected from the film group of Table 1, and the other film was made into the film which saponified Fujitaek TD60UL.

(Evaluation of Polarizer)

Parallel light was irradiated to the obtained polarizing plate, the transmission image was reflected on the screen, and the presence or absence of the stripe-shaped contrast derived from the linear unevenness | corrugation of an optical film was visually examined. Table 1 shows A when not recognized, B is acknowledged slightly (1 to 5 of the 10 examiners), and B is acknowledged (6 or more among 10 examiners). ) Is described in C.

[Polarization degree]

The transmittance | permeability Tp at the time of superimposing the absorption axes and the absorption axis orthogonally orthogonally superposed the two produced polarizing plates was measured, and the polarization degree P was computed from the following formula.

Polarization degree P = ((Tp-Tc ') / (Tp + Tc')) ^0.5

1] initial polarization degree

As a result of calculating the degree of polarization of the polarizing plate by the above-mentioned method, the degree of polarization of all the polarizing plates was 99.9%.

2] time-lapse polarization degree

The film (film manufactured in the said Example and a comparative example) side of the said polarizing plate was bonded together to the glass plate with an adhesive, it was left to stand for 500 hours on 60 degreeC and 90% of relative humidity, and the polarization degree after leaving (time As a result of calculating the progressive polarization degree) by the method mentioned above, the polarization degree of all the polarizing plates was 99.9%.

At this time, in the polarizing plate using the film of Table 1, peeling was not observed at all except the polarizing plate using the film 7, whereas in the polarizing plate using the film 7, slight peeling was confirmed in the vicinity of the interface of the polarizing film and the film 7.

3] Evaluation of mounting on liquid crystal display

(Mounting on IPS type liquid crystal display device)

In a commercially available liquid crystal television (LED slim type 42 type liquid crystal television in IPS mode), among the pair of polarizing plates sandwiching the liquid crystal cell, the polarizing plate on the backlight side is peeled off, and the film side of Table 1 shows the produced polarizing plate as the liquid crystal. It was rebonded to the liquid crystal cell via an adhesive so that it might be arrange | positioned at the cell side. When the display characteristics of the recombined liquid crystal television were confirmed, and the luminance and color taste from the front and the inclination were confirmed, the same characteristics as those before peeling off the polarizing plate were shown. Moreover, the luminance nonuniformity at the time of black display when observed from the front of an apparatus was observed, and the following references | standards evaluated (initial evaluation). The evaluation results are shown in Table 1.

(Light non-uniformity in the front direction)

The luminance nonuniformity at the time of black display when observed from the front of an apparatus was observed, and the following references | standards evaluated.

A: Nonuniformity is not recognized at all in the environment of roughness 1001x.

B: Nonuniformity is hardly recognized under the environment of roughness 1001x

C: Faint nonuniformity is visualized in an environment of roughness 1001x

D: Clear nonuniformity is recognized in the environment of roughness 1001x.

E: Under the environment of roughness 3001x, a clear nonuniformity is recognized.

Furthermore, after holding for 10 days in an environment of 50 ° C and a relative humidity of 80%, the solution was transferred to an environment of 25 ° C and a relative humidity of 60%, continuously lit in a black display state, and visually observed after 48 hours to evaluate light non-uniformity. (Forced evaluation). The evaluation results are shown in Table 1.

(Light non-uniformity in the oblique direction)

The luminance nonuniformity and the color taste nonuniformity at the time of black display in 45 degrees of azimuth directions and 70 degrees of polar angle directions from the front of an apparatus were observed, and the following references | standards evaluated.

A: Nonuniformity is not recognized at all in the environment of roughness 1001x.

B: Nonuniformity is hardly recognized under the environment of roughness 1001x

C: Faint nonuniformity is visualized in an environment of roughness 1001x

D: Clear nonuniformity is recognized in the environment of roughness 1001x.

E: Under the environment of roughness 3001x, a clear nonuniformity is recognized.

In Table 1 below, the total amount (Ct) is the content in the three-layer total, and the film thickness (d) is the total thickness of the three-layer total.

As is apparent from the results shown in Table 1, the optical films 4 and 5 of the comparative examples having a linear concave and / or convex shape having a height exceeding 30 nm and 300 nm or less in an interval of any 1000 mm are When the polarizing plate which fell to the external appearance of the roll after elapse of time, and used this as a protective film, streaks generate | occur | produce, it is understood that the light nonuniformity generate | occur | produces when the liquid crystal display device which inserted this is observed from the front. Moreover, as for the optical film 7 of the comparative example which does not have linear concave and / or convex shape whose height is 3-30 nm, as mentioned above, some peeling generate | occur | produced in the vicinity of the interface of a polarizing film and the film 7. Film 8 of the comparative example which does not satisfy Ct / d≥0.375 shows that the light nonuniformity at the time of obliquely observing the liquid crystal display device using this is generated.

On the other hand, all of the optical films of the examples were excellent in the appearance of the roll, and the polarizing plate using this as a protective film had little generation of streaks, and the liquid crystal display device incorporating this had little light unevenness when observed from the front and obliquely. Able to know.

Claims (9)

As an optical film containing 1 or 2 or more types of additives, and a cellulose ester,
The total content of the additive (Ct; unit: mass% relative to the cellulose ester) and the film thickness (d; unit µm) satisfy a relationship of Ct / d ≧ 0.375,
Has one or more linear concave and / or convex shapes having a height of 3 to 30 nm in any 1000 mm section,
The optical film which has a linear concave and / or convex shape whose height exceeds 30 nm and is 300 nm or less in arbitrary 1000 mm sections, or has one or less. The method of claim 1,
The optical film of which the said optical film contains a thickener further. 3. The method according to claim 1 or 2,
The optical film whose viscosity average degree of polymerization of the said cellulose ester is 180-550. 3. The method according to claim 1 or 2,
The optical film whose acyl substitution degree with respect to the hydroxyl group of the said cellulose ester is 2.60-3.00. The laminated body which has a film laminated part formed by winding or bending of the optical film of Claim 1 or 2, or by overlapping 2 or more of the said optical films. Retardation film containing the optical film of Claim 1 or 2 at least. The polarizing plate containing at least the optical film of Claim 1 or 2. The image display apparatus containing the optical film of Claim 1 or 2 at least. The method of claim 8,
An image display device, wherein the image display device is a liquid crystal display device in an IPS mode or a VA mode.