JP5255859B2 - Cellulose body composition, cellulose body film, retardation film, optical compensation film, antireflection film, polarizing plate and image display device - Google Patents

Description

  The present invention relates to a cellulose composition, a cellulose film, a retardation film, an optical compensation film, an antireflection film, a polarizing plate and a liquid crystal display device, and more specifically, in-plane retardation (Re) and retardation in the thickness direction. The present invention relates to a cellulose film having a large value of (Rth) and low dependency of Re and Rth on humidity and having an appropriate glass transition temperature and mechanical properties, an optical compensation film, a polarizing plate and an image display device using them.

  In recent years, with the widespread use of liquid crystal display devices, demands for display performance and durability have increased, and response speeds have been improved, and a wider viewing angle such as contrast and color balance when viewed from an oblique direction with respect to the display image. It has become a problem to compensate with. In order to solve these problems, VA (Vertical Alignment), OCB (Optical Compensated Bend), or IPS (In-Plane Switching) display elements have been developed. There is a demand for an optical film material having a foundation development property. In particular, the retardation film is required to control the in-plane retardation (Re) and the thickness direction retardation (Rth) according to each of various liquid crystal systems.

  Cellulose acylate films are widely used as polarizing plate protective films for liquid crystal display devices because of their transparency and toughness. For example, an optical film in which a fatty acid cellulose ester such as cellulose acetate propionate or cellulose acetate butyrate is formed has been proposed (see, for example, Patent Document 1). However, Re and Rth obtained with these films are limited and are not sufficient as retardation films. Recently, a film that can widely control retardation using cellulose acylate substituted with a long-chain acyl group having a large carbon number has been proposed (see, for example, Patent Documents 2 to 4). However, these films have a low glass transition temperature (Tg), have a problem in mechanical strength, and lack practicality as an optical film. Recently, a highly stretched film of a mixed acylate of a linear carboxylic acid having 5 to 22 carbon atoms and acetic acid has been proposed (for example, see Patent Document 5). However, this film was an optical film showing low birefringence. Furthermore, it is difficult for films using cellulose acylates substituted with these linear acyl groups to achieve both an appropriate glass transition temperature (Tg) and a reduction in retardation humidity dependency.

JP 2000-352620 A International Publication No. 05/062085 Pamphlet International Publication No. 06/090700 Pamphlet International Publication No. 05/022215 Pamphlet JP 2006-249221 A

  In view of the above problems, the present invention has little change in in-plane retardation (Re) and thickness direction retardation (Rth) due to humidity fluctuation, has an appropriate glass transition temperature (Tg), and Re, Rth. An object of the present invention is to provide a cellulosic film capable of controlling a wide range of values, a retardation film, an optical compensation film, an antireflection film, a polarizing plate and an image display device using the same.

（一般式（２）中、Ｒ ⁴ 、Ｒ ⁵ 、Ｒ ⁶ 、Ｒ ⁷ およびＲ ⁸ はそれぞれ独立に水素原子またはアル キル基を表す。ただし、Ｒ ⁶ 、Ｒ ⁷ およびＲ ⁸ のうち、少なくとも２つはアルキル基である 。なお、＊の部分はセルロース骨格との結合手を表す。）
[２] 前記セルロース体が下記式（Ｉ）を満たす [１]に記載のセルロース体組成物。
式（Ｉ）：０．１≦ＤＳＡ＜１．５４（式中、ＤＳＡはセルロースの水酸基の水素原子 を置換している前記アシル基（Ａ）の置換度を表す。）
[３] 前記セルロース体が更に炭素数２〜４の脂肪族アシル基（Ｂ）を有し、下記式（Ｉ Ｉ）を満たす[１]または[２]に記載のセルロース体組成物。
式（ＩＩ）：２．０≦ＤＳＡ＋ＤＳＢ≦３．０（式（ＩＩ）中、ＤＳＡはセルロースの 水酸基の水素原子を置換している前記アシル基（Ａ）の置換度、ＤＳＢは前記アシル基（ Ｂ）の置換度を表す。）
[４] 前記アシル基（Ｂ）がアセチル基である[３]に記載のセルロース体組成物。
[５] 前記アシル基（Ａ）が２−エチルヘキサノイル基またはｔ−ブチルアセチル基であ る[１]〜[４]のいずれか１項に記載のセルロース体組成物。
[６] [１]〜[５]のいずれか１項に記載のセルロース体組成物により形成されたセルロー ス体フィルム
[７] [６]記載のセルロース体フィルムからなる位相差フィルム。
[８] [６]に記載のセルロース体フィルムまたは [７]に記載の位相差フィルム上に、液 晶性化合物を配向させて形成した光学異方性層を有する光学補償フィルム。
[９] [６]に記載のセルロース体フィルムまたは[7]に記載の位相差フィルム上に、反射 防止層を有する反射防止フィルム。
[１０] 偏光膜と該偏光膜を挟持する２枚の保護フィルムとからなる偏光板であって、２ 枚の保護フィルムの少なくとも一方が、[６]に記載のセルロース体フィルム、[７]に記載 の位相差フィルム、[８]に記載の光学補償フィルム、[９]に記載の反射防止フィルムのい ずれかを少なくとも１枚含む偏光板。
[１１] [６]に記載のセルロース体フィルム、[７]に記載の位相差フィルム、[８]に記載 の光学補償フィルム、[９]に記載の反射防止フィルム、[１０]に記載の偏光板のいずれか を少なくとも１枚含む画像表示装置。
本発明は、上記[１]〜[１１]に関するものであるが、その他の事項についても参考のた めに記載した。
〔１〕炭素数５から炭素数３０の分岐構造を含む脂肪族アシル基（Ａ）を有するセルロース体を含有するセルロース体組成物。
〔２〕前記アシル基（Ａ）が下記一般式（１）で表される基である上記〔１〕に記載のセルロース体組成物。
一般式（１）： The above object of the present invention has been achieved by the following means.
[1] A cell containing a cellulose body having a branched structure and having an aliphatic acyl group (A) having 5 to 30 carbon atoms ( including carbonyl carbon of an acyl group) represented by the following general formula (2) Loin body composition.
General formula (2):

(In the general formula (2) represents R ^4, R ^5, R ^6, R ⁷ and R ⁸ each independently represent a hydrogen atom or aralkyl kill group. However, of R ^6, R ⁷ and R ^8, at least 2 Is an alkyl group, where the part * represents a bond to the cellulose skeleton.)
[2] The cellulose body composition according to [1], wherein the cellulose body satisfies the following formula (I).
Formula (I): 0.1 ≦ DSA <1.54 (wherein DSA represents the degree of substitution of the acyl group (A) substituting the hydrogen atom of the hydroxyl group of cellulose )
[3] The cellulose body composition according to [1] or [2], wherein the cellulose body further has an aliphatic acyl group (B) having 2 to 4 carbon atoms and satisfies the following formula ( II).
Formula (II): 2.0 ≦ DSA + DSB ≦ 3.0 (In Formula (II), DSA represents the substitution degree of the acyl group (A) substituting the hydrogen atom of the hydroxyl group of cellulose , and DSB represents the acyl group ( Represents the degree of substitution of B).)
[4] The cellulose composition according to [3], wherein the acyl group (B) is an acetyl group.
[5] The acyl group (A) is Ru 2-ethyl hexanoyl group or t- butyl acetyl der [1] to cellulosic composition according to any one of [4].
[6] [1] cellulose scan substance film formed by cellulose composition according to any one of to [5]
[7] A retardation film comprising the cellulose film according to [6].
[8] on the retardation film according to the cellulosic substance film or [7] according to [6], an optical compensation film having an optical anisotropic layer formed by orienting a liquid crystalline compound.
[9] An antireflection film having an antireflection layer on the cellulose film according to [6] or the retardation film according to [7] .
[10] A polarizing plate comprising a polarizing film and two protective films sandwiching the polarizing film, wherein at least one of the two protective films is the cellulose body film according to [6], [7] the retardation film according, optical compensation film as described in [8], a polarizing plate comprising at least one or have displacement of an antireflection film as described in [9].
[11] Cellulosic film according to [6], retardation film according to [7], optical compensation film according to [8], antireflection film according to [9], polarized light according to [10] An image display device including at least one plate .
The present invention is concerned with the above-mentioned [1] to [11], described in order references were also for other matters.
[1] A cellulose composition containing a cellulose body having an aliphatic acyl group (A) containing a branched structure having 5 to 30 carbon atoms.
[2] The cellulose composition according to [1], wherein the acyl group (A) is a group represented by the following general formula (1).
General formula (1):

(In General Formula (1), R ¹ represents an alkyl group. R ² and R ³ each independently represent a hydrogen atom or an alkyl group, provided that at least one of R ² and R ³ is an alkyl group. (Note that the * part represents a bond with the cellulose skeleton.)
[3] The cellulose composition according to [1], wherein the acyl group (A) is a group represented by the following general formula (2).
General formula (2):

(In the general formula (2), R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group, provided that at least two of R ⁶ , R ⁷ and R ⁸ Is an alkyl group, where * represents a bond to the cellulose skeleton.)
[4] The cellulose composition according to any one of [1] to [3], wherein the cellulose body satisfies the following formula (I).
Formula (I): 0.1 ≦ DSA <1.54
(In the formula, DSA represents the degree of substitution of the acyl group (A) substituting the hydrogen atom of the hydroxyl group of cellulose.)
[5] The cellulose composition according to any one of [1] to [4], wherein the cellulose further has an aliphatic acyl group (B) having 2 to 4 carbon atoms and satisfies the following formula (II): .
Formula (II): 2.0 ≦ DSA + DSB ≦ 3.0
(In formula (II), DSA represents the degree of substitution of the acyl group (A) substituting the hydrogen atom of the hydroxyl group of cellulose, and DSB represents the degree of substitution of the acyl group (B).)
[6] The cellulose composition according to [5], wherein the acyl group (B) is an acetyl group.
[7] The cellulose composition according to [1] to [6], wherein the acyl group (A) is a 2-ethylhexanoyl group or a t-butylacetyl group.
[8] A cellulose film formed from the cellulose composition according to any one of [1] to [7] [9] A retardation film comprising the cellulose film according to [8].
[10] An optical compensation film having an optically anisotropic layer formed by orienting a liquid crystalline compound on the cellulose film according to [8] or the retardation film according to [9].
[11] An anti-reflection film having an antireflection layer on the cellulose film according to [8] or the retardation film according to [9].
[12] A polarizing plate comprising a polarizing film and two protective films sandwiching the polarizing film, wherein at least one of the two protective films is the cellulose body film according to the above [8], [9] A polarizing plate comprising at least one of the retardation film according to [10], the optical compensation film according to [10], and the antireflection film according to [11].
[13] The cellulose film described in [8], the retardation film described in [9], the optical compensation film described in [10], the antireflection film described in [11], and the film described in [12] An image display device including at least one polarizing plate.

  The cellulose body composition of the present invention forms a cellulose body film having a moderate glass transition temperature (Tg) with little change in in-plane retardation (Re) and thickness direction retardation (Rth) due to humidity fluctuations. be able to. The cellulose film of the present invention can be suitably used for a retardation film, an optical compensation film, an antireflection film, a polarizing plate, an image display device and the like, and can exhibit excellent display performance.

The contents of the present invention will be described in detail below.
The present invention relates to a cellulose composition containing a cellulose having an aliphatic acyl group (A) containing a branched structure having 5 to 30 carbon atoms.
In the present invention, “having an aliphatic acyl group (A)” means that oxygen is bonded to the aliphatic acyl group (A) in any one of the hydroxyl groups of the glucose unit of cellulose. Means.

<Cellulose body>
The aliphatic acyl group (A) having a branched structure in the present invention (hereinafter sometimes referred to as “acyl group (A)”) is an acyl group having 5 to 30 carbon atoms and containing an unsaturated bond. Preferably, it is an acyl group having 5 to 20 carbon atoms, more preferably 6 to 18 carbon atoms, and most preferably 8 to 18 carbon atoms.

In the present invention, the acyl group (A) is preferably a group represented by the following general formula (1).
General formula (1):

(In General Formula (1), R ¹ represents an alkyl group. R ² and R ³ each independently represent a hydrogen atom or an alkyl group, provided that at least one of R ² and R ³ is an alkyl group. (Note that the * part represents a bond with the cellulose skeleton.)
In the present invention, the group represented by the general formula (1) is bonded to the oxygen atom of the hydroxyl group of the glucose unit of cellulose by a bond represented by *.
Examples of the alkyl group represented by R ^{1 to} R ³ include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, Vinyl group, allyl group, 2-butenyl group, 3-pentenyl group, tert-butyl group, 2-methylbutyl group, isobarrel group, 2-ethylbutyl group, 2,2-dimethylbutyl group, 2-methylbarrel group, 3- Methyl barrel group, 4-methyl barrel group, 2-propylpentyl group, 2-methylhexyl group, 2-ethylhexyl group, 2-methyl-2-pentyl group, 2,2 Dimethylpentyl group, 2-Okuchiiru like can be mentioned groups, these groups may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. Preferably, methyl group, ethyl group, propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group A group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, and n-nonadecyl group.

The cellulose body film formed from the cellulose body composition containing the cellulose body in which the acyl group (A) is a group represented by the general formula (1) is retardationd while maintaining an appropriate glass transition temperature (Tg). This is preferable because it can reduce the humidity dependence.
If the glass transition temperature of the cellulosic film is too low, the film may be softened by heating in the drying step or the like during the production process. Since the cellulose body film of the present invention has an appropriate glass transition temperature, there is an advantage in production in that such a problem can be avoided.

In the present invention, the acyl group (A) is preferably a group represented by the following general formula (2).
General formula (2):

(In the general formula (2), R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or an alkyl group, provided that at least two of R ⁶ , R ⁷ and R ⁸ Is an alkyl group, where * represents a bond to the cellulose skeleton.)
In the present invention, the group represented by the general formula (2) is bonded to the oxygen atom of the hydroxyl group of the glucose unit of cellulose by a bond represented by *.
Examples of the alkyl group represented by R ^{4 to} R ⁸ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, Vinyl group, allyl group, 2-butenyl group, 3-pentenyl group, tert-butyl group, 2-methylbutyl group, isobarrel group, 2-ethylbutyl group, 2,2-dimethylbutyl group, 2-methylbarrel group, 3- Methyl barrel group, 4-methyl barrel group, 2-propylpentyl group, 2-methylhexyl group, 2-ethylhexyl group, 2-methyl-2-pentyl group, 2,2 Dimethylpentyl group, 2-Okuchiiru like can be mentioned groups, these groups may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. Preferably, methyl group, ethyl group, propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group A group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, and n-nonadecyl group.

  The cellulose body film formed from the cellulose body composition containing the cellulose body in which the acyl group (A) is a group represented by the general formula (2) is retardationd while maintaining an appropriate glass transition temperature (Tg). This is preferable because it can reduce the humidity dependence.

  Specific examples of the aliphatic acyl group (A) having a branched structure include 2-methylbutanoyl group, isovaleryl group, 2-ethylbutanoyl group, t-butylacetyl group, 2-methylvaleryl group, 3-methylvaleryl group, 4-methylvaleryl group, 2-propylpentanoyl group, 2-methylhexanoyl group, 2-ethylhexanoyl group, isostearoyl group, tiglinoyl group, 3,3-dimethylacrylic group, 2-methyl-2-pentenoyl group, citronellyl Group, and the like.

  Among these, t-butylacetyl group, 2-methylvaleryl group, 3-methylvaleryl group, 4-methylvaleryl group, 2-propylpentanoyl group, 2-methylhexanoyl group, 2-ethylbutanoyl group, 2-ethyl are preferable. Examples include hexanoyl group, isostearoyl group, tiglinoyl group, 3,3-dimethylacrylic group, 2-methyl-2-pentenoyl group, citronellyl group, and the like.

  More preferably, t-butylacetyl group, 2-methylvaleryl group, 3-methylvaleryl group, 4-methylvaleryl group, 2-propylpentanoyl group, 2-methylhexanoyl group, 2-ethylbutanoyl group, 2-ethylhexayl group A noyl group, an isostearoyl group, and a citronellyl group.

  Most preferred are 2-ethylhexanoyl group and t-butylacetyl group.

It is preferable that the cellulose body composition of this invention contains the cellulose body which satisfy | fills following formula (I).
Formula (I) 0.1 <DSA <1.54
In the formula, DSA represents the degree of substitution of the acyl group (A) substituting the hydrogen atom of the hydroxyl group of cellulose.

Preferably the following formula (Ia) is satisfied, more preferably the formula (Ib) is satisfied.
Formula (Ia) 0.1 <DSA ≦ 1.0
Formula (Ib) 0.1 ≦ DSA ≦ 0.85
By setting DSA within the above range, it is preferable because Tg can be kept at a certain value and the humidity dependency of retardation can be reduced. If DSA is too large, Tg will be small, and if DSA is too small, the humidity dependency of retardation will be large.

The cellulose body of the present invention preferably includes a cellulose body having an aliphatic acyl group (B) having 2 to 4 carbon atoms and satisfying the following formula (II) in addition to the acyl group (A).
Specific examples of the acyl group (B) include an acetyl group, a propionyl group, a butyryl group, and an isobutyryl group. More preferably, an acetyl group, a propionyl group, and a butyryl group can be mentioned, and an acetyl group can be particularly preferably mentioned.

Formula (II) 2.0 ≦ DSA + DSB ≦ 3.0
In the formula, DSA represents the degree of substitution of the acyl group (A) substituting the hydrogen atom of the hydroxyl group of cellulose, and DSB represents the degree of substitution of the aliphatic acyl group (B) having 2 to 4 carbon atoms.

Preferably the following formula (IIa) is satisfied, more preferably the formula (IIb) is satisfied.
Formula (IIa) 2.0 <DSA + DSB ≦ 3.0
Formula (IIb) 2.2 <DSA + DSB ≦ 3.0
By setting DSA + DSB within the above range, solubility in organic solvents such as methylene chloride and acetone is improved, which is preferable.

Here, DSA and DSB represent the degree of substitution of the acyl group (A) and the acyl group (B), respectively. Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. In the present invention, the degree of substitution indicates a ratio in which any one of hydroxyl groups at the 2-position, 3-position and 6-position is substituted with a specific substituent. When the hydroxyl groups at the 2nd, 3rd and 6th positions are all substituted with substituents, the degree of substitution is 3.0. Further, in the present invention, DSA + DSB represents the total degree of substitution, and represents the degree of substitution of all substituents substituting the 2-position, 3-position and 6-position hydroxyl groups. In the present invention, the substitution degree and substitution degree distribution of substituents are determined by ¹³ C-NMR using the method described in Cellulose Communication 6, 73-79 (1999) and Carbohydrate Research 273, 83-91 (1995). Can be determined.

  Although the preferable example of the cellulose body which satisfy | fills Formula (I) and Formula (II) is shown in following Table 1, this invention is not limited to these specific examples.

  In the present invention, the cellulose body refers to a compound having a cellulose skeleton obtained by introducing a functional group biologically or chemically using cellulose as a raw material, and cellulose acylate is preferred.

  The raw material cotton of cellulose acylate used in the present invention has a low degree of polymerization obtained by acid hydrolysis of wood pulp such as microcrystalline cellulose as well as natural cellulose such as cotton linter and wood pulp (hardwood pulp, conifer pulp). (Polymerization degree 100-300) A cellulose can also be used and may be mixed and used depending on the case. Detailed descriptions of these raw material celluloses can be found in, for example, “Plastic Materials Course (17) Fibrous Resin” (Marusawa, Uda, Nikkan Kogyo Shimbun, published in 1970) and Invention Association Publication Technical Report 2001-1745 ( 7 to 8) and “Encyclopedia of Cellulose (page 523)” (edited by Cellulose Society, Asakura Shoten, published in 2000) can be used, and is not particularly limited.

  The viscosity average degree of polymerization of cellulose acylate is preferably 300 to 700, more preferably 350 to 500, and most preferably 400 to 500. By setting the average degree of polymerization to 500 or less, the viscosity of the dope solution of the cellulose body does not become too high, and the film production by casting tends to be easy. Moreover, it is preferable for the degree of polymerization to be 140 or more because the strength of the produced film tends to be further improved. The average degree of polymerization can be measured by the intrinsic viscosity method of Uda et al. (Kazuo Uda, Hideo Saito, “Journal of the Textile Society”, Vol. 18, No. 1, pages 105-120, 1962). Specifically, it can be measured according to the method described in JP-A-9-95538.

  Cellulose bodies used in the present invention include, for example, cellulose acetate manufactured by Aldrich (acetyl substitution degree 2.45), or cellulose acetate manufactured by Daicel Corporation (acetyl substitution degree 2.41 (trade name: L-70), 2.15 ( The product name: FL-70)) can be used as a starting material and can be obtained by reaction with the corresponding acid chloride. In addition, cellulose acetate having a low degree of acetyl substitution is obtained by synthesizing an intermediate having a degree of acetyl substitution of 1.80 by the method described in Synthesis Example 1 described later using Aldrich microcrystalline cellulose as a starting material, and then corresponding acid chloride. It can obtain by reaction with.

  The degree of substitution of the acyl group (A) can be controlled by the temperature in the acylation reaction, the reaction time, the type and amount of acid chloride and base. The degree of substitution of the acyl group (A) can be adjusted depending on the type of cellulose acetate used as the starting material.

<Cellulose body composition>
The cellulose body composition of the present invention preferably contains 70% by weight or more of the whole cellulose composition, more preferably 80% by weight or more, and most preferably 90% by weight or more.
The cellulose composition of the present invention can take various shapes such as particles, powders, fibers, lumps, solutions, melts, and films.
Since the raw material for film production is preferably in the form of particles or powder, the cellulose acylate composition after drying is subjected to pulverization and sieving for uniform particle size and improved handling. Also good. When the cellulose acylate composition is in the form of particles, 90% by mass or more of the particles used preferably have a particle size of 0.5 to 5 mm. Moreover, it is preferable that 50 mass% or more of the particle | grains to be used have a particle size of 1-4 mm. The cellulose acylate composition particles preferably have a shape as close to a sphere as possible. The cellulose acylate composition of the present invention preferably has an apparent density of 0.5 to 1.3 g / cm ³ , more preferably 0.7 to 1.2 g / cm ³ , and particularly preferably 0.8 to 1. .15 g / cm ³ . The method for measuring the apparent density is defined in JIS K-7365.

  In the present invention, only one type of cellulose body may be used, or two or more types may be mixed and used. Moreover, polymer components other than the cellulose body of the present invention and various additives can be appropriately mixed. The component to be mixed is preferably one having excellent compatibility with the cellulose body, and the transmittance when formed into a film is preferably 80% or more, more preferably 90% or more, and particularly preferably 92% or more. Is desirable.

  In the present invention, the cellulose body generally contains various additives that can be added to cellulose acylate (for example, an ultraviolet ray preventive agent, a plasticizer, a deterioration preventing agent, fine particles, an optical property adjusting agent, etc.) and a composition. can do. In addition, the additive may be added to the cellulose body in any of the dope preparation steps, and these additives may be added as a preparation step at the end of the dope preparation step.

  These additives may be solid or oily. That is, the melting point and boiling point are not particularly limited. For example, an ultraviolet absorber at 20 ° C. or lower and an ultraviolet absorber at 20 ° C. or higher can be mixed and used, and similarly, a plasticizer can be mixed and used. Specifically, the method described in JP 2001-151901 A can be employed.

(Stabilizer)
In the present invention, it is effective to add a stabilizer in order to maintain the stability of the cellulose body during high-temperature melt film formation. In particular, it is preferable to add at least one selected from a phenol-based stabilizer having a molecular weight of 500 or more and a phosphite-based stabilizer or a thioether-based stabilizer having a molecular weight of 500 or more. As the preferred phenol-based stabilizer, any known phenol-based stabilizer can be used. Preferable phenolic stabilizers include hindered phenolic stabilizers. In particular, it is preferable to have a substituent at a site adjacent to the phenolic hydroxyl group. In this case, the substituent is preferably a substituted or unsubstituted alkyl group having 1 to 22 carbon atoms, such as a methyl group, an ethyl group, a propionyl group, An isopropionyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, an isopentyl group, a t-pentyl group, a hexyl group, an octyl group, an isooctyl group, and a 2-ethylhexyl group are more preferable. Moreover, the stabilizer which has a phenol group and a phosphite group in the same molecule is also mentioned as a preferable material.

  These are readily available as commercial products and are sold by the following manufacturers. From Ciba Specialty Chemicals, Irganox 1076, Irganox 1010, Irganox 3113, Irganox 245, Irganox 1135, Irganox 1330, Irganox 259, Irganox 565, Irganx 565, Ir35x1025 Moreover, it can obtain from Asahi Denka Kogyo Co., Ltd. as ADK STAB AO-50, ADK STAB AO-60, ADK STAB AO-20, ADK STAB AO-70, and ADK STAB AO-80. Furthermore, from Sumitomo Chemical Co., Ltd., it can obtain as Sumilizer BP-76, Sumilizer BP-101, Sumilizer GA-80. In addition, it is also possible to obtain as Sinox 326M and Sinox 336B from Sipro Kasei Co., Ltd.

  It is also preferable to contain a phosphite stabilizer having a molecular weight of 500 or more that has an antioxidant effect. Examples of these compounds include the compounds described in JP-A No. 2004-182979, [0023] to [0039], JP-A No. 51-70316, JP-A No. 10-306175, JP-A No. 57-. No. 78431, JP-A-54-157159, and JP-A-55-13765. In addition, as other stabilizers, it is selected from the materials described in detail on pages 17 to 22 of the Japan Institute of Invention Information (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention). Can be used. These are commercially available from Asahi Denka Kogyo Co., Ltd. as ADK STAB 1178, 2112, PEP-8, PEP-24G, PEP-36G, HP-10, and Sandostab P-EPQ from Clariant. Is possible.

  As the thioether stabilizer, any known thioether stabilizer can be used. It is commercially available from Sumitomo Chemical Co. as Sumilizer TPL, TPM, TPS and TDP. It is also available from Asahi Denka Kogyo Co., Ltd. as ADK STAB AO-412S. In the use of these stabilizers, at least one phenol-based stabilizer and at least one selected from a phosphite-based stabilizer or a thioether-based stabilizer are each 0.02 to 3% by mass with respect to cellulose acylate. It is preferable to contain, Especially preferably, it is 0.05-1 mass% containing. The ratio of the content of the phenol stabilizer and the phosphite stabilizer or thioether stabilizer is not particularly limited, but is preferably 1/10 to 10/1 (parts by mass), more preferably 1 / 5 to 5/1 (parts by mass), more preferably 1/3 to 3/1 (parts by mass), and particularly preferably 1/3 to 2/1 (parts by mass).

  In the present invention, a stabilizer having a phenol group and a phosphite group in the same molecule is also recommended. Those materials are described in JP-A-10-273494. As a commercially available product, Sumilizer GP (Sumitomo Chemical Co., Ltd.) can be mentioned. Further, a long chain aliphatic amine described in JP-A-61-63686, a compound containing a sterically hindered amine group described in JP-A-6-329830, and a hindered dye described in JP-A-7-90270. Peridinyl light stabilizers and organic amines described in JP-A-7-278164 may also be used. Preferred amine stabilizers are ADK STAB LA-57, LA-52, LA-67, LA-62, LA-77 from Asahi Denka, and TINUVIN 765, 144 from Ciba Specialty Chemicals. It is commercially available. The use ratio of amines to phosphites is usually about 0.01 to 25% by mass.

(Plasticizer)
If a plasticizer is added to molten cellulose acylate, the crystal melting temperature (Tm) of cellulose acylate can be lowered. Although the molecular weight of the plasticizer used for this invention is not specifically limited, Preferably a high molecular weight plasticizer is mentioned, For example, molecular weight is preferable 500 or more, More preferably, it is 550 or more, Furthermore, 600 or more is preferable. Examples of the plasticizer include phosphate esters, alkylphthalyl alkyl glycolates, carboxylic acid esters, and fatty acid esters of polyhydric alcohols. These plasticizers may be solid or oily. That is, the melting point and boiling point are not particularly limited. When performing melt film formation, those having non-volatility can be particularly preferably used.

  Examples of phosphate esters include triphenyl phosphate, tricresyl phosphate, and phenyl diphenyl phosphate.

  Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl Ethyl glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl Glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalate Ethyl glycolate, and the like.

  Examples of carboxylic acid esters include phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, and diethylhexyl phthalate, and acetyltrimethyl citrate, acetyltriethyl citrate, and acetyltributyl citrate. Citric acid esters of In addition, it is also preferable to use butyl oleate, methyl acetyl linoleate, dibutyl sebacate, triacetin or the like alone or in combination.

  The amount of these plasticizers added is preferably 0% by mass to 15% by mass, more preferably 0% by mass to 10% by mass, and particularly preferably 0% by mass to 8% by mass of the cellulose acylate used for melt film formation. . These plasticizers may be used in combination of two or more as required.

(UV absorber)
An ultraviolet inhibitor may be added to the cellulose composition used for melt film formation. With respect to the ultraviolet ray inhibitor, JP-A-60-235852, JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107854, JP-A-6-118233. 6-148430, 7-11056, 7-11055, 7-11056, 8-29619, 8-239509, and JP-A-2000-204173. . The addition amount is preferably 0.01 to 2% by mass, more preferably 0.01 to 1.5% by mass of the melt (melt) to be prepared.

  These ultraviolet absorbers are available as the following commercial products. As benzotriazoles, TINUBIN P (Ciba Specialty Chemicals), TINUBIN 234 (Ciba Specialty Chemicals), TINUBIN 320 (Ciba Specialty Chemicals), TINUBIN 326 (Ciba Specialty Chemicals) TINUBIN 327 (Ciba Specialty Chemicals), TINUBIN 328 (Ciba Specialty Chemicals), Sumisorb 340 (Sumitomo Chemical), Adekas Type LA-31 (Asahi Denka Kogyo Co., Ltd.), etc. . In addition, as benzophenone-based ultraviolet absorbers, Seasorb 100 (manufactured by Sipro Kasei Co., Ltd.), Seasorb 101 (manufactured by Sipro Kasei Co., Ltd.), Seasorb 101S (manufactured by Sipro Kasei Co., Ltd.), Seasorb 102 (manufactured by Sipro Kasei Co., Ltd.), Seasorb 103 (Sipro Kasei) Kasei Co., Ltd.), Adekas Type LA-51 (Asahi Denka Kogyo Co., Ltd.), Chemisorp 111 (Chemipro Kasei Co., Ltd.), UVINUL D-49 (BASF Corp.), and the like. Examples of oxalic acid anilide UV absorbers include TINUBIN 312 (manufactured by Ciba Specialty Chemicals) and TINUBIN 315 (manufactured by Ciba Specialty Chemicals). In addition, as a salicylic acid ultraviolet absorber, Seasorb 201 (manufactured by Sipro Kasei) and Seasorb 202 (manufactured by Sipro Kasei) are marketed, and as a cyanoacrylate ultraviolet absorber, Seasorb 501 (manufactured by Sipro Kasei), UVINUL N-539 (BASF) is available.

(Fine particles)
In the present invention, it is also preferable to add fine particles to the cellulose acylate composition used for melt film formation.
In the present invention, the fine particles include inorganic compound fine particles or organic compound fine particles, and either one or both of them may be included. The average primary particle size of the fine particles contained in the cellulose body in the present invention is preferably 5 nm to 3 μm, more preferably 5 nm to 2.5 μm, and particularly preferably 20 nm to 2.0 μm. The addition amount of the fine particles is preferably 0.005 to 1.0% by mass, more preferably 0.01 to 0.8% by mass, and further 0.02 to 0.4% by mass with respect to the cellulose acylate. Is particularly preferred. In the present invention, the “average primary particle size” refers to the particle size of fine particles in a dispersed state (non-aggregated state). The average primary particle size is determined by dynamic light scattering (several nm-1 μm), laser diffraction (0 0.1 μm to several thousand μm) and a laser diffraction / scattering method (several tens nm to 1 μm) based on Mie theory.

Preferable examples of the inorganic compound fine particles include SiO ₂ , ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , ZrO ₂ , In ₂ O ₃ , MgO, BaO, MoO ₂ , V ₂ O ₅ , talc, clay, Examples include calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate. Preferably, at least one of SiO ₂ , ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , ZrO ₂ , In ₂ O ₃ , MgO, BaO, MoO ₂ , and V ₂ O ₅ is preferable, and SiO 2 is more preferable. ₂ , TiO ₂ , SnO ₂ , Al ₂ O ₃ , ZrO ₂ .

As the SiO ₂ fine particles, for example, commercially available products such as Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above, manufactured by Nippon Aerosil Co., Ltd.) can be used. As the ZrO ₂ fine particles, for example, commercially available products such as Aerosil R976 and R811 (above, manufactured by Nippon Aerosil Co., Ltd.) can be used. Seahoster KE-E10, E30, E40, E50, E50, E70, E150, W10, W30, W50, P10, P30, P50, P100, P150, P250 ) Etc. are also used. Silica microbeads P-400 and 700 (catalyst chemical industry Co., Ltd. products) can also be used. SO-G1, SO-G2, SO-G3, SO-G4, SO-G5, SO-G6, SO-E1, SO-E2, SO-E3, SO-E4, SO-E5, SO-E6, SO- C1, SO-C2, SO-C3, SO-C4, SO-C5, and SO-C6 (manufactured by Admatechs Co., Ltd.) can also be used. Furthermore, silica particles (a powdered water dispersion) 8050, 8070, 8100, and 8150 manufactured by Moritex Corporation can also be used.

  Preferable examples of the organic compound fine particles include polymers such as silicone resins, fluorine resins, and acrylic resins, and silicone resins are particularly preferable. The silicone resin preferably has a three-dimensional network structure, such as Tospearl 103, 105, 108, 120, 145, 3120, and 240 (above, manufactured by Toshiba Silicone Co., Ltd.). Commercial products having a trade name can be used.

Furthermore, the fine particles comprising an inorganic compound are preferably surface-treated in order to stably exist in the cellulose composition and the film. The inorganic fine particles are preferably used after being subjected to a surface treatment. The surface treatment method includes chemical surface treatment using a coupling agent and physical surface treatment such as plasma discharge treatment and corona discharge treatment. In the present invention, the use of a coupling agent is preferred. As the coupling agent, an organoalkoxy metal compound (for example, a silane coupling agent, a titanium coupling agent, etc.) is preferably used. When inorganic fine particles are used as the fine particles (especially when SiO ₂ is used), treatment with a silane coupling agent is particularly effective. An organosilane compound can be used as the silane coupling agent. Although the usage-amount of the said silane coupling agent is not specifically limited, It is recommended to use 0.005-5 mass% preferably with respect to an inorganic fine particle, Furthermore, 0.01-3 mass% is preferable.
The fine particles may be mixed with the cellulose body in any step of film formation. In the step of producing cellulose acylate, the fine particles are added in any step before reprecipitation, and the fine particles are contained. Reprecipitation is also preferred.

(Release agent)
It is also preferable that the cellulose composition used for melt film formation contains a compound having a fluorine atom. The compound having a fluorine atom can exhibit an action as a release agent, and may be a low molecular weight compound or a polymer. Examples of the polymer include the polymers described in JP-A No. 2001-269564. A polymer having a fluorine atom is preferably a polymer obtained by polymerizing a monomer containing an ethylated unsaturated monomer containing a fluorinated alkyl group as an essential component. The fluorinated alkyl group-containing ethylenically unsaturated monomer related to the polymer is not particularly limited as long as it is a compound having an ethylenically unsaturated group and a fluorinated alkyl group in the molecule. A surfactant having a fluorine atom can also be used, and a nonionic surfactant is particularly preferable.

(Pelletization)
The cellulose body and the additive are preferably mixed and pelletized prior to melt film formation.
Pelletization can be made by melting the cellulose body and the additive at 150 ° C. to 250 ° C. using a biaxial or uniaxial kneading extruder and then solidifying and cutting the noodle-shaped extrudate. Pelletization may be performed by an underwater cut method in which the material is cut while being extruded directly into water. More preferably, the kneading and extruding machine is a vent type and is pelletized while decompressing. Further, it is more preferable to pelletize the inside of the kneading extruder while substituting with nitrogen.
Preferably, the pellet size is such cross-sectional area is 1 mm ² to 300 mm ^2, a length 1Mm～30mm, and more preferably the cross-sectional area of 2 mm ² 100 mm ^2, length 1.5Mm～10mm.
The number of revolutions of the extruder is preferably 10 rpm to 1000 rpm, more preferably 30 rpm to 500 rpm. The extrusion residence time in pelletization is 10 seconds to 30 minutes, preferably 30 seconds to 3 minutes.

[Cellulose body film]
The present invention also relates to a cellulosic film.
The cellulose body film in the present invention is a cellulose body film formed from the cellulose composition of the present invention.
The cellulose body film of the present invention preferably contains 50% by weight or more, more preferably 80% or more, and most preferably 95% or more of the cellulose body.

  Although the manufacturing method of the cellulose body film of this invention is not specifically limited, It is preferable to manufacture with the melt film forming method or the solution film forming method described below.

<Melting film formation>
The preferable form in the case of manufacturing the cellulose body film of this invention by a melt film forming method is demonstrated.

  The melt viscosity at 230 ° C. of the cellulose composition used for melt film formation (the melt viscosity at 230 ° C. of the cellulose acylate film produced) is preferably 150 Pa · sj to 1000 Pa · s. . Such a melt viscosity can be realized by setting the substituent composition within the range of the present invention and adjusting the molecular weight. If the molecular weight is larger than the preferred range, the melt viscosity becomes too high and film formation may be difficult. On the other hand, if the degree of polymerization is too smaller than the preferred range, the strength as a film will be too low, and the melt viscosity will be too low to allow sufficient shearing during kneading, resulting in insufficient kneading.

(Specific method of melt film formation)
Below, the specific method of melt film forming is demonstrated.
(1) Drying It is preferable to dry the moisture in the pellets prior to melt film formation. A preferable moisture content is 0.1 mass% or less, More preferably, it is 0.01 mass% or less.

(2) Melt extrusion The dried cellulosic resin is fed into the cylinder from the feed port of the extruder.
The screw compression ratio of the extruder is preferably 2.5 to 4.5, more preferably 3.0 to 4.0. L (screw length) / D (screw diameter) is preferably 20 to 70. More preferably, it is 24-50. The melting temperature is preferably performed at the above-described temperature.
In order to prevent the oxidation of the resin, it is more preferable to carry out the inside of the extruder in an inert (nitrogen or the like) air stream or while evacuating it using a vented extruder.

(3) Filtration It is preferable to perform breaker plate type filtration at the exit of the extruder.
For high-precision filtration, it is preferable to provide a leaf type disk filter type filtration device after passing through the gear pump. Filtration may be performed in a single stage or in multiple stages.

(4) Gear pump It is preferable to install a gear pump between the extruder and the die in order to improve the thickness accuracy (reduction in fluctuations in the discharge amount). Moreover, it is preferable for the extrusion pressure stabilization to reduce the temperature fluctuation of the adapter connecting the extruder and the gear pump, the gear pump and the die, and the like.

(5) Die As long as the molten resin stays in the die, any type of commonly used T-die, fishtail die, and hanger coat die may be used. It is also preferable to insert a static mixer for improving the uniformity of the resin temperature immediately before the T die.
The preferred residence time of the resin from the supply port through the extruder until it exits the die is 2 minutes to 60 minutes, more preferably 4 minutes to 30 minutes.

(6) Casting The molten resin extruded from the die onto the sheet is cooled and solidified on the casting drum to obtain a film. At this time, it is also preferable to use a touch roll.
It is preferable to use 1 to 8 casting drums, more preferably 2 to 5 casting drums, and slowly cool them. Then, it peels off from a casting drum, winds up after passing through a nip roll. The thickness of the unstretched film thus obtained is preferably 30 μm to 400 μm, more preferably 50 μm to 200 μm.

(7) Winding It is preferable to trim both ends before winding. The trimmed portion may be reused as a film raw material. The take-up tension may be taken up with a constant take-up tension, but it is more preferable that the take-up tension is tapered and taken up according to the take-up diameter. It is also possible to adjust the draw ratio between the nip rolls so that the film is not subjected to a tension higher than the specified tension in the middle of the line.
Prior to winding, a laminate film may be attached to at least one side.

The residual organic solvent amount of the cellulose film of the present invention is preferably 0.03% by mass or less, more preferably 0.02% or less, and particularly preferably 0.01% or less. When the residual solvent is in such a range, it is preferable that the odor of the solvent is not generated and the characteristic change of the film due to the evaporation of the solvent hardly occurs. The melt film forming method is an effective method for reducing the residual solvent.
The amount of the residual solvent can be measured by a gas chromatography method or the like.

<Solution casting>
Next, the preferable form in the case of manufacturing the cellulose body of this invention with a solution casting method is demonstrated.
In the present invention, the solvent of the cellulose body is not particularly limited as long as the cellulose body can be dissolved and cast and formed, and the object can be achieved. Preferred solvents include chlorinated organic solvents such as dichloromethane, chloroform, 1,2-dichloroethane, tetrachloroethylene, and non-chlorinated organic solvents.
The non-chlorine organic solvent used in the present invention is preferably a solvent selected from esters, ketones and ethers having 3 to 12 carbon atoms. Esters, ketones and ethers may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO— and —COO—) can also be used as a main solvent, such as an alcoholic hydroxyl group. It may have a functional group of In the case of the main solvent having two or more kinds of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

  The non-chlorine organic solvent used in the present invention is not particularly limited as long as the object can be achieved as long as the cellulose body can be dissolved, cast, and formed into a film. These chlorinated organic solvents are preferably dichloromethane and chloroform. Particularly preferred is dichloromethane. In addition, there is no particular problem in mixing an organic solvent other than the chlorinated organic solvent. In that case, it is necessary to use at least 50% by mass of dichloromethane. The non-chlorine organic solvent used in combination with the present invention is described below. That is, as a preferable non-chlorine organic solvent, a solvent selected from esters, ketones, ethers, alcohols, hydrocarbons and the like having 3 to 12 carbon atoms is preferable. Esters, ketones, ethers and alcohols may have a cyclic structure. A compound having two or more functional groups of esters, ketones and ethers (that is, —O—, —CO— and —COO—) can also be used as a solvent. For example, other functional groups such as alcoholic hydroxyl groups can be used. You may have group simultaneously. In the case of a solvent having two or more types of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.

  The alcohol used in combination with the chlorinated organic solvent may be linear, branched or cyclic, and among them, saturated aliphatic hydrocarbon is preferable. The hydroxyl group of the alcohol may be any of primary to tertiary. Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. As the alcohol, fluorine-based alcohol is also used. Examples thereof include 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol and the like. Furthermore, the hydrocarbon may be linear, branched or cyclic. Either aromatic hydrocarbons or aliphatic hydrocarbons can be used. The aliphatic hydrocarbon may be saturated or unsaturated. Examples of hydrocarbons include cyclohexane, hexane, benzene, toluene and xylene.

  The non-chlorine organic solvent used in combination with the chlorine-based organic solvent that is the main solvent used in the cellulose body is not particularly limited, but methyl acetate, ethyl acetate, methyl formate, ethyl formate, acetone, dioxolane, dioxane, It is selected from ketones or acetoacetates having 4 to 7 carbon atoms, alcohols or hydrocarbons having 1 to 10 carbon atoms. Preferred non-chlorine organic solvents used in combination are methyl acetate, acetone, methyl formate, ethyl formate, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl acetyl acetate, methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol. , 2-butanol, and cyclohexanol, cyclohexane, and hexane.

  It is preferable to dissolve 10 to 35% by mass of the cellulose body of the present invention in an organic solvent. More preferably, it is 13-30 mass%, and it is especially preferable that it is the cellulose acylate solution which melt | dissolved 15-28 mass%. The method of carrying out the cellulose body at these concentrations may be carried out so that the cellulose body has a predetermined concentration at the stage of dissolution, or a concentration step which will be described later after being prepared in advance as a low concentration solution (for example, 9 to 14% by mass) May be adjusted to a predetermined high concentration solution. Furthermore, after the high-concentration cellulose body solution is added in advance, various additives may be added to obtain a predetermined low-concentration cellulose body solution, and the cellulose body solution concentration of the present invention is achieved by any method. If there is no problem.

  About the preparation of the cellulose body solution (dope) of this invention, the melt | dissolution method is not specifically limited, Room temperature may be sufficient, Furthermore, it implements by the cooling melt | dissolution method or the high temperature melt | dissolution method, Furthermore, these combinations. Regarding these, for example, JP-A-5-163301, JP-A-61-106628, JP-A-58-127737, JP-A-9-95544, JP-A-10-95854, JP-A-10-45950, JP 2000-53784, JP 11-322946, JP 11-322947, JP 2-276830, JP 2000-273239, JP 11-71463, JP 04-259511, Special JP-A-2000-273184, JP-A-11-323017, JP-A-11-302388 and the like describe methods for preparing a cellulose acylate solution. The above-described method for dissolving cellulose acylate in an organic solvent is applicable to the present invention as long as it is within the scope of the present invention. The details of these methods, particularly for non-chlorine-based solvent systems, are described in detail on pages 22 to 25 of the Japan Institute of Invention Technology (Publication No. 2001-1745, published on March 15, 2001, Japan Society of Invention). Will be implemented. Further, the cellulose body solution of the present invention is usually subjected to solution concentration and filtration, and similarly described in detail on page 25 of the Japan Society for Invention and Technology (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society of Invention). Has been. In addition, when it melt | dissolves at high temperature, it is the case where it is more than the boiling point of the organic solvent to be used, and in that case, it uses in a pressurized state.

  It is preferable that the cellulose body solution of this invention is the range with the viscosity and dynamic storage elastic modulus of the solution. 1 mL of the sample solution was measured with a rheometer (CLS 500) using a Steel Cone having a diameter of 4 cm / 2 ° (both manufactured by TA Instruments). Measurement conditions were measured by varying the range from 40 ° C. to −10 ° C. at 2 ° C./min using an Oscillation Step / Temperature Ramp, static non-Newtonian viscosity n * (Pa · s) at 40 ° C., and storage at −5 ° C. The elastic modulus G ′ (Pa) was determined. Note that the measurement was started after the sample solution was kept warm until the liquid temperature became constant at the measurement start temperature. In the present invention, the viscosity at 40 ° C. is 1 to 400 Pa · s, the dynamic storage elastic modulus at 15 ° C. is preferably 500 Pa or more, more preferably the viscosity at 40 ° C. is 10 to 200 Pa · s, The dynamic storage elastic modulus at 15 ° C. is preferably 1 to 1,000,000. Furthermore, it is preferable that the dynamic storage elastic modulus at a low temperature is large. For example, when the casting support is −5 ° C., the dynamic storage elastic modulus is preferably 10,000 to 1,000,000 Pa at −5 ° C. When a body is -50 degreeC, it is preferable that the dynamic storage elastic modulus in -50 degreeC is 10,000-5 million Pa.

(Specific method of solution casting)
Next, the manufacturing method of the cellulose body of this invention is described. As a method and equipment for producing the cellulose acylate film of the present invention, a solution casting film forming method and a solution casting film forming apparatus conventionally used for producing a cellulose acylate film are used. The dope (cellulose body solution) prepared from the dissolving machine (kettle) is temporarily stored in a storage kettle, and the foam contained in the dope is defoamed for final preparation. The dope is fed from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the number of revolutions, and the dope is run endlessly from the die (slit) of the pressure die. The dry-dried dope film (also referred to as web) is peeled off from the metal support at a peeling point that is uniformly cast on the metal support and substantially rounds the metal support. Both ends of the obtained web are sandwiched between clips, transported by a tenter while keeping the width, dried, then transported by a roll group of a drying device, dried, and wound up to a predetermined length by a winder. The combination of the tenter and the roll group dryer varies depending on the purpose. In the solution casting film forming method used for silver halide photographic light-sensitive materials and functional protective films for electronic displays, in addition to the solution casting film forming apparatus, an undercoat layer, an antistatic layer, an antihalation layer, a protective layer, etc. In many cases, a coating device is added to the surface processing of the film. Each of these manufacturing processes is described in detail on pages 25 to 30 of the Japan Society of Invention Public Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society of Invention). Including), metal support, drying, peeling, stretching and the like.

  Here, although the space temperature of a casting part is not specifically limited in this invention, It is preferable that it is -50-50 degreeC. Furthermore, it is preferable that it is -30-40 degreeC, and it is especially preferable that it is -20-30 degreeC. In particular, the cellulose body solution cast by the space temperature at a low temperature can hold the film containing the organic solvent by instantaneously cooling on the support and increasing the gel strength. Thereby, it becomes possible to peel off from a support body in a short time, without evaporating an organic solvent from a cellulose body, and high-speed casting can be achieved. The means for cooling the space may be normal air, nitrogen, argon, helium or the like, and is not particularly limited. In that case, the relative humidity is preferably 0 to 70%, more preferably 0 to 50%. Moreover, in this invention, the temperature of the support body of the casting part which casts a cellulose body solution is -50-130 degreeC, Preferably it is -30-25 degreeC, Furthermore, it is -20-15 degreeC. In order to keep the casting part at the temperature of the present invention, it may be achieved by introducing a cooled gas into the casting part, or a cooling device may be arranged in the casting part to cool the space. At this time, it is important to take care not to attach water, and it can be carried out by a method such as using dry gas.

  In the present invention, the following configurations are particularly preferred for the contents and casting of each layer. That is, the cellulose body solution is a cellulose acylate solution containing 0.1 to 20% by mass of at least one liquid or solid plasticizer with respect to cellulose acylate at 25 ° C. and / or at least It is a cellulose body solution containing 0.001 to 5% by mass of one liquid or solid ultraviolet absorber with respect to the cellulose body, and / or an average particle size of 5 to 5 of at least one solid. A cellulose acylate solution containing 0.001 to 5% by mass of fine particle powder of 3000 nm with respect to the cellulose body, and / or at least one fluorosurfactant to the cellulose acylate A cellulose acylate solution containing 0.001 to 2% by mass, and / or at least It is a cellulose body solution containing 0.0001 to 2% by mass of a seed release agent with respect to cellulose acylate, and / or 0.0001 to at least one kind of deterioration inhibitor with respect to cellulose acylate. A cellulose body solution containing 2% by mass and / or containing at least one optical anisotropy control agent in an amount of 0.1 to 15% by mass with respect to cellulose acylate; and / or It is a cellulose body solution containing 0.1 to 5% by mass of at least one infrared absorber with respect to the cellulose body, and a cellulose body film produced therefrom. Is preferred.

  In the casting step, one type of cellulose acylate solution may be cast as a single layer, or two or more types of cellulose body solutions may be cast simultaneously and / or sequentially. In the case of having a casting process consisting of two or more layers, in the cellulose body solution and the cellulose body film to be produced, the composition of the chlorinated solvent in each layer is either the same or different, and the addition of each layer The additive is either one type or a mixture of two or more types, the addition position of the additive to each layer is either the same layer or a different layer, in the additive solution The concentration of each layer is either the same concentration or a different concentration, the aggregate molecular weight of each layer is either the same or a different aggregate molecular weight, and the temperature of the solution in each layer is Either the same or different temperature, the coating amount of each layer is either the same or different, the viscosity of each layer is the same or different It is either one, the thickness of each layer after drying is either the same or different, and the materials present in each layer are in the same state or distribution, or in different states or distributions A cellulose body solution characterized in that the physical properties of each layer are either the same or different physical properties, and the physical properties of each layer are either uniform or a distribution of different physical properties, and It is also preferable that it is a cellulose body film produced from a solution. Here, the physical properties include physical properties described in detail on pages 6 to 7 of the Japan Society of Invention Public Technical Report (Public Technical Number 2001-1745, issued on March 15, 2001, Japan Society of Inventions). Haze, transmittance, spectral characteristics, retardation Re, Rth, molecular orientation axis, axial misalignment, tear strength, folding strength, tensile strength, roll-in / out Rt difference, creaking, dynamic friction, alkali hydrolysis, curl value, moisture content , Residual solvent amount, heat shrinkage rate, high humidity dimensional evaluation, moisture permeability, base flatness, dimensional stability, heat shrinkage start temperature, elastic modulus, and measurement of bright spot foreign matter, and base evaluation The impedance and surface shape used in the above are also included. In addition, the Yellow Index, Transparency, Thermophysical Properties (Tg, Crystallization) of Cellulosic Body, which is described in detail on page 11 of the Japan Institute of Invention Technology (public technical number 2001-1745, published on March 15, 2001, Japan Society of Invention). Heat).

<Treatment of cellulosic film>
(Stretching)
The cellulose body film of the present invention produced by the melt film forming method or the solution film forming method as described above is stretched for the purpose of improving the surface shape, expressing Re, Rth, improving the linear expansion coefficient, and the like. Is preferred.
Stretching may be performed on-line during the film forming process, or may be performed off-line after winding up once after film formation is completed. That is, in the case of melt film formation, stretching may be performed at a stage where cooling during film formation is not completed, or may be performed after completion of cooling.
Stretching is preferably performed at Tg to (Tg + 50 ° C.), more preferably (Tg + 1 ° C.) to (Tg + 30 ° C.), and particularly preferably (Tg + 2 ° C.) to (Tg + 20 ° C.). A preferable draw ratio is 0.1% to 500%, more preferably 10% to 300%, and particularly preferably 30% to 200%. These stretching operations may be performed in one stage or in multiple stages. The draw ratio here is determined using the following equation.
Stretch ratio (%) = 100 × {(Length after stretching) − (Length before stretching)} / Length before stretching

Such stretching is performed by longitudinal stretching, lateral stretching, and combinations thereof. Longitudinal stretching includes (1) roll stretching (stretching in the longitudinal direction using two or more pairs of nip rolls with increased peripheral speed on the outlet side), (2) fixed end stretching (holding both ends of the film, And the like can be used. Further, for the transverse stretching, tenter stretching (stretching by stretching both sides of the film with a chuck and stretching it in the transverse direction (perpendicular to the longitudinal direction)) can be used. These longitudinal stretching and lateral stretching may be performed alone (uniaxial stretching) or in combination (biaxial stretching). In the case of biaxial stretching, it may be carried out in the longitudinal and transverse sequential manners (sequential stretching) or simultaneously (simultaneous stretching).
The stretching speed of longitudinal stretching and lateral stretching is preferably 10% / min to 10000% / min, more preferably 20% / min to 1000% / min, particularly preferably 30% / min to 800% / min. In the case of multistage stretching, the average value of the stretching speed of each stage is indicated.

Following such stretching, it is also preferable to relax by 0% to 10% in the longitudinal or transverse direction. Furthermore, it is also preferable to heat-fix at 150-250 degreeC for 1 second-3 minutes following extending | stretching.
The film thickness after stretching in this manner is preferably 10 to 300 μm, more preferably 20 μm to 200 μm, and particularly preferably 30 μm to 100 μm.

  The angle θ formed by the film forming direction (longitudinal direction) and the slow axis of Re of the film is preferably closer to 0 °, + 90 °, or −90 °. That is, in the case of longitudinal stretching, the closer to 0 °, the better, preferably 0 ± 3 °, more preferably 0 ± 2 °, and particularly preferably 0 ± 1 °. In the case of transverse stretching, 90 ± 3 ° or −90 ± 3 ° is preferable, 90 ± 2 ° or −90 ± 2 ° is more preferable, and 90 ± 1 ° or −90 ± 1 ° is particularly preferable.

  In order to suppress light leakage when the polarizing plate is viewed obliquely, it is necessary to arrange the transmission axis of the polarizing film and the slow axis in the plane of the cellulose film in parallel. Since the transmission axis of the roll film-like polarizing film produced continuously is generally parallel to the width direction of the roll film, the protection comprising the roll film-like polarizing film and the roll film-like cellulose body film In order to continuously bond the films, the in-plane slow axis of the roll film-like protective film needs to be parallel to the width direction of the film. Therefore, it is preferable to stretch more in the width direction. The stretching process may be performed in the middle of the film forming process, or the original fabric that has been formed and wound may be stretched. In the former case, stretching may be performed in a state containing a residual solvent, and the stretching can be preferably performed at a residual solvent amount of 2 to 30% by mass.

  The thickness of the cellulosic film preferably used in the present invention obtained after drying varies depending on the purpose of use, is preferably in the range of 5 to 500 μm, more preferably in the range of 20 to 300 μm, and 30 to 150 μm. More preferably, it is the range. Moreover, it is preferable that it is 40-110 micrometers for optical use, especially for VA liquid crystal display devices. The film thickness may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the metal support speed, and the like so as to obtain a desired thickness.

  The width of the cellulose body film obtained as described above is preferably 0.5 to 3 m, more preferably 0.6 to 2.5 m, and still more preferably 0.8 to 2.2 m. The length is preferably 100 to 10,000 m per roll, more preferably 500 to 7000 m, and still more preferably 1000 to 6000 m. When winding, it is preferable to give knurling to at least one end, the knurling width is preferably 3 mm to 50 mm, more preferably 5 mm to 30 mm, and the height is preferably 0.5 to 500 μm, more preferably 1 to 200 μm. is there. This may be a single push or a double push.

  The above-mentioned unstretched or stretched cellulose film may be used alone, or may be used in combination with a polarizing plate, a liquid crystal layer or a layer with a controlled refractive index (low reflective layer) or A hard coat layer may be provided for use.

(Optical properties of cellulose film)
In the present invention, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at the wavelength λ, respectively. Re (λ) is measured in “KOBRA 21ADH” (manufactured by Oji Scientific Instruments Co., Ltd.) by making light having a wavelength of λ nm incident in the normal direction of the film. Rth (λ) is the direction inclined by + 40 ° with respect to the film normal direction, with Re (λ) and the in-plane slow axis (determined by “KOBRA 21ADH”) as the tilt axis (rotation axis). With the retardation value measured by making light of wavelength λnm incident from the light and the slow axis in the plane as the tilt axis (rotation axis), the light of wavelength λnm from the direction tilted by −40 ° with respect to the film normal direction “KOBRA 21ADH” is calculated based on the retardation values measured in a total of three directions, the assumed value of the average refractive index, and the input film thickness value.
Here, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). By inputting the assumed value of the average refractive index and the film thickness, nx, ny, and nz can be calculated by “KOBRA 21ADH”.

  Re of the cellulosic film of the present invention, in the case of an oriented film sample, is obtained by multiplying the thickness by the value obtained by subtracting the refractive index in the MD direction (direction perpendicular to the TD direction) from the refractive index in the TD direction (alignment direction). Value (ie, Re = (nx−ny) d). Therefore, when Re is positive, it means that the refractive index (nx) in the TD direction is larger than the refractive index (ny) in the MD direction.

  Rth is the refractive index in the thickness direction from the average value of the refractive index in the longitudinal direction and the refractive index in the width direction (in the case of an oriented film described later, the average value of the refractive index in the TD direction and the refractive index in the MD direction). The value obtained by subtracting the rate is multiplied by the thickness (that is, Rth = {(nx + ny) / 2−nz} d). Therefore, when Rth is positive, it means that the average value ((nx + ny) / 2) of the in-plane refractive index is larger than the refractive index (nz) in the thickness direction.

  In the cellulose film of the present invention, Re and Rth can be adjusted by the total substitution degree, the substitution degree distribution of the 2-position, 3-position and 6-position of the substituent and the draw ratio.

  The variation in Re (590) value in the width direction of the film is preferably ± 5 nm, more preferably ± 3 nm. Further, the variation in the Rth (590) value in the width direction is preferably ± 10 nm, and more preferably ± 5 nm. Moreover, it is preferable that the variation in the Re value and the Rth value in the length direction is also within the range of the variation in the width direction.

(Equilibrium moisture content)
The moisture content was measured by the Karl Fischer method using a cellulose acylate film sample of 7 mm × 35 mm of the present invention with a moisture meter and a sample drying apparatus (Aqua Counter AQ-200, LE-20S, both Hiranuma Sangyo Co., Ltd.). taking measurement. It is calculated by dividing the amount of water (g) by the sample mass (g).

  The equilibrium moisture content of the cellulose acylate film of the present invention is preferably 0 to 3% at 25 ° C. and 80% RH. It is more preferably 0.1 to 2%, and particularly preferably 0.3 to 1.5%. An equilibrium water content of 3% or more is not preferable because the dependency of retardation on humidity change is large when used as a support for an optical compensation film, and the optical compensation performance is lowered.

When the cellulosic film of the present invention is used in the VA mode and the OCB mode, it is used only on either one of the top and bottom sides of the cell (two-sheet type) in which one sheet is used on each side of the cell. There are two forms (one-sheet type).
In the case of the two-sheet type, Re (590) is preferably 20 to 100 nm, and more preferably 30 to 70 nm. Rth (590) is preferably from 70 to 300 nm, more preferably from 100 to 200 nm.
In the case of a single sheet type, Re (590) is preferably 30 to 150 nm, and more preferably 40 to 100 nm. Rth (590) is preferably from 100 to 300 nm, more preferably from 150 to 250 nm.

(Haze)
The cellulosic film of the present invention preferably has a value measured using, for example, a haze meter (1001DP type, manufactured by Nippon Denshoku Industries Co., Ltd.) of 0.1 or more and 0.8 or less. It is more preferably 0.7 or more and 0.7 or less, and particularly preferably 0.1 or more and 0.60 or less. By controlling the haze within the above range, a high-contrast image can be obtained when incorporated in a liquid crystal display device as an optical compensation film.

(Photoelastic coefficient)
The cellulose-based film of the present invention is preferably used as a polarizing plate protective film or a retardation plate. When used as a polarizing plate protective film or a retardation plate, birefringence (Re, Rth) may change due to stress due to expansion and contraction due to moisture absorption. The change in birefringence due to such stress can be measured as a photoelastic coefficient, and the range is preferably 5 × 10 ⁻⁷ (cm ² / kgf) to 30 × 10 ⁻⁷ (cm ² / kgf), and 6 More preferably, it is preferably 10 × 10 ⁻⁷ (cm ² / kgf) to 25 × 10 ⁻⁷ (cm ² / kgf), and 7 × 10 ⁻⁷ (cm ² / kgf) to 20 × 10 ⁻⁷ (cm ² / kgf). It is particularly preferred.

(surface treatment)
The unstretched or stretched cellulose body film can be subjected to surface treatment in some cases to achieve improved adhesion between the cellulose body 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 here may be low-temperature plasma that occurs in a low-pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferable. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Details of these are described in detail on pages 30 to 32 of the Japan Society of Invention Disclosure Technical Bulletin (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society of Invention). Note that, in the plasma treatment at atmospheric pressure which has been attracting attention in recent years, for example, irradiation energy of 20 to 500 Kgy is used under 10 to 1000 Kev, and more preferably irradiation energy of 20 to 300 Kgy is used under 30 to 500 Kev. Among these, alkali saponification treatment is particularly preferable, and it is extremely effective as the surface treatment of the cellulose body film.

  The alkali saponification treatment may be immersed in a saponification solution or coated with a saponification solution. In the case of the dipping method, it can be achieved by passing an aqueous solution of pH 10 to 14 such as NaOH or KOH through a bath heated to 20 ° C. to 80 ° C. for 0.1 to 10 minutes, and then neutralizing, washing with water and drying. .

  In the case of the coating method, a dip coating method, a curtain coating method, an extrusion coating method, a bar coating method, and an E-type coating method can be used. The solvent of the alkali saponification coating solution has good wettability because it is applied to the transparent support of the saponification solution, and the surface state remains good without forming irregularities on the surface of the transparent support by the saponification solution solvent. It is preferred to select a solvent to keep. Specifically, an alcohol solvent is preferable, and isopropyl alcohol is particularly preferable. An aqueous solution of a surfactant can also be used as a solvent. The alkali of the alkali saponification coating solution is preferably an alkali that dissolves in the above solvent, and more preferably KOH or NaOH. The pH of the saponification coating solution is preferably 10 or more, more preferably 12 or more. The reaction conditions during the alkali saponification are preferably 1 second to 5 minutes at room temperature, more preferably 5 seconds to 5 minutes, and particularly preferably 20 seconds to 3 minutes. After the alkali saponification reaction, it is preferable to wash the surface on which the saponification solution is applied with water or acid, and then with water. Moreover, the coating-type saponification treatment and the alignment film coating described later can be performed continuously, and the number of steps can be reduced. Specific examples of these saponification methods are described in JP 2002-82226 A and WO 02/46809 pamphlet.

It is also preferable to provide an undercoat layer for adhesion to the functional layer. This layer may be applied after the above surface treatment or may be applied without the surface treatment. Details of the undercoat layer are described on page 32 of the Japan Institute of Invention and Innovation (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention).
These surface treatment and undercoating processes can be incorporated at the end of the film forming process, can be performed alone, or can be performed in the functional layer application process described later.

[Phase difference film]
The cellulose body film of the present invention can be used as a retardation film.
In addition, the functional layer described in detail on pages 32 to 45 of the Invention Association public technical bulletin (public technical number 2001-1745, issued March 15, 2001, Invention Association) on the cellulose body film of the present invention. It is preferable to combine them. Among these, application of a polarizing film (formation of a polarizing plate), application of an optical compensation layer (optical compensation film), and application of an antireflection layer (antireflection film) are preferable.

[Optical compensation film]
The present invention also relates to an optical compensation film having an optically anisotropic layer formed by aligning a liquid crystalline compound on a cellulose film or a retardation film.

<Application of optical compensation layer (production of optical compensation film)>
The optically anisotropic layer is for compensating the liquid crystal compound in the liquid crystal cell in the black display of the liquid crystal display device, and forms an alignment film on the cellulose body film and further provides the optically anisotropic layer. Is formed.

(Alignment film)
An alignment film is provided on the surface-treated cellulose body film. This film has a function of defining the alignment direction of liquid crystalline molecules. However, if the alignment state is fixed after the alignment of the liquid crystalline compound, the alignment film plays the role and is not necessarily an essential component. That is, it is also possible to produce a polarizing plate using the cellulose body film of the present invention by transferring only the optically anisotropic layer on the alignment film in which the alignment state is fixed onto the polarizer.

  The alignment film is an organic compound (for example, ω-tricosanoic acid) formed by rubbing treatment of an organic compound (preferably polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). , Dioctadecylmethylammonium chloride, methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known.

The alignment film is preferably formed by polymer rubbing treatment. In principle, the polymer used for the alignment film has a molecular structure having a function of aligning liquid crystal molecules.
In the present invention, in addition to the function of aligning liquid crystalline molecules, the crosslinkability of bonding side chains having a crosslinkable functional group (for example, a double bond) to the main chain or aligning liquid crystalline molecules. It is preferable to introduce a functional group into the side chain.

  As the polymer used for the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used. Examples of the polymer include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylolacrylamide) described in paragraph [0022] of JP-A-8-338913, for example. ), Polyester, polyimide, vinyl acetate copolymer, carboxymethyl cellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (for example, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol) are preferable, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are more preferable, and polyvinyl alcohol and modified polyvinyl alcohol are particularly preferable. . It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization. The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

  A side chain having a function of aligning liquid crystal molecules generally has a hydrophobic group as a functional group. The specific type of functional group is determined according to the type of liquid crystal molecule and the required alignment state.

  For example, the modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Examples include substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy groups, dialkoxy groups, monoalkoxy groups), and the like. Specific examples of these modified polyvinyl alcohol compounds include those described in paragraph numbers [0022] to [0145] of JP-A No. 2000-155216 and paragraph numbers [0018] to [0022] of JP-A No. 2002-62426, for example. Etc.

  When the side chain having a crosslinkable functional group is bonded to the main chain of the alignment film polymer or the crosslinkable functional group is introduced into the side chain having the function of aligning liquid crystal molecules, the alignment film polymer and optical anisotropy are obtained. The polyfunctional monomer contained in the layer can be copolymerized. As a result, not only between the polyfunctional monomer and the polyfunctional monomer, but also between the alignment film polymer and the alignment film polymer and between the polyfunctional monomer and the alignment film polymer is firmly bonded by a covalent bond. Therefore, the strength of the optical compensation film can be remarkably improved by introducing the crosslinkable functional group into the alignment film polymer.

  The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] of JP-A No. 2000-155216. Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent.

  Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole, and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] of JP-A No. 2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.

  0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high-temperature and high-humidity atmosphere for a long time, sufficient durability without generation of reticulation can be obtained.

  The alignment film can basically be formed by applying a solution containing the above-mentioned polymer, which is an alignment film forming material, and a crosslinking agent onto a transparent support, followed by drying by heating (crosslinking) and rubbing treatment. . As described above, the crosslinking reaction may be performed at any time after coating on the transparent support. When a water-soluble polymer such as polyvinyl alcohol is used as the alignment film forming material, the coating liquid is preferably a mixed solvent of an organic solvent (for example, methanol) having a defoaming action and water. The ratio of water: methanol is preferably 0: 100 to 99: 1, and more preferably 0: 100 to 91: 9. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an alignment film and also an optically anisotropic layer reduces remarkably.

  The alignment film is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, or roll coating. A rod coating method is particularly preferable. The film thickness after drying is preferably 0.1 to 10 μm. Heat drying can be normally performed at 20 degreeC-110 degreeC. In order to form sufficient cross-linking, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is more preferable. The drying time can usually be 1 minute to 36 hours, but is preferably 1 minute to 30 minutes. The pH is also preferably set to an optimum value for the crosslinking agent to be used. When glutaraldehyde is used, the pH is usually 4.5 to 5.5, and 5 is particularly preferable.

The alignment film is provided on the transparent support or the undercoat layer. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above.
For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment step performed when manufacturing a liquid crystal display device can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth or the like in which fibers having a uniform length and thickness are planted on average.

When industrially implemented, this is achieved by bringing a rotating rubbing roll into contact with the film with the polarizing film being transported. However, the roundness, cylindricity, and deflection (eccentricity) of the rubbing roll can be any. Is preferably 30 μm or less. The film wrap angle on the rubbing roll is preferably 0.1 to 90 °. However, as described in JP-A-8-160430, a stable rubbing treatment can be obtained by winding 360 ° or more. As for the conveyance speed of a film, 1-100 m / min is preferable. It is preferable to select an appropriate rubbing angle in the range of 0 to 60 °. When used for a liquid crystal display device, 40 to 50 ° is preferable. 45 ° is particularly preferred.
The thickness of the alignment film thus obtained is preferably in the range of 0.1 to 10 μm.

(Optically anisotropic layer)
Next, the liquid crystalline molecules of the optically anisotropic layer are aligned on the alignment film. Thereafter, if necessary, the alignment film polymer is reacted with the polyfunctional monomer contained in the optically anisotropic layer, or the alignment film polymer is crosslinked using a crosslinking agent.
The liquid crystalline molecules used in the optically anisotropic layer include rod-like liquid crystalline molecules and discotic liquid crystalline molecules. The rod-like liquid crystal molecules and the disk-like liquid crystal molecules may be high-molecular liquid crystals or low-molecular liquid crystals, and further include those in which low-molecular liquid crystals are cross-linked and no longer exhibit liquid crystallinity.

1) Rod-like liquid crystalline molecules As rod-like liquid crystalline molecules, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines Alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used.

The rod-like liquid crystalline molecule includes a metal complex. In addition, a liquid crystal polymer containing a rod-like liquid crystalline molecule in a repeating unit can also be used as the rod-like liquid crystalline molecule. In other words, the rod-like liquid crystal molecule may be bonded to a (liquid crystal) polymer.
For rod-like liquid crystalline molecules, see Chapter 4, Chapter 7 and Chapter 11 of the Chemistry of the Quarterly Chemistry Vol. 22 (1994) The Chemical Society of Japan, and the 142th Committee of the Japan Society for the Promotion of Science. Described in Chapter 3.
The birefringence of the rod-like liquid crystal molecule is preferably in the range of 0.001 to 0.7.

  The rod-like liquid crystalline molecule preferably has a polymerizable group in order to fix its alignment state. The polymerizable group is preferably a radically polymerizable unsaturated group or a cationically polymerizable group. Specifically, for example, the polymerizable group and the polymerization described in paragraphs [0064] to [0086] of JP-A-2002-62427 are exemplified. Liquid crystal compounds.

2) Discotic liquid crystalline molecules The discotic liquid crystalline molecules include benzene derivatives described in the research report of C. Destrade et al., Mol. Cryst. 71, 111 (1981), C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990), Torxene derivatives described in B. Kohne et al., Angew Chem. 96, 70 (1984), cyclohexane derivatives and JM Lehn et al., J. Chem. Commun., 1794 (1985), J. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994) includes azacrown and phenylacetylene macrocycles.

  As a discotic liquid crystalline molecule, a compound having liquid crystallinity having a structure in which a linear alkyl group, an alkoxy group, and a substituted benzoyloxy group are radially substituted as a side chain of the mother nucleus with respect to the mother nucleus at the center of the molecule Is also included. The molecule or the assembly of molecules is preferably a compound having rotational symmetry and imparting a certain orientation. In the optically anisotropic layer formed from the discotic liquid crystalline molecules, the compound finally contained in the optically anisotropic layer does not need to be a discotic liquid crystalline molecule. Also included are compounds having a group that reacts with heat or light and, as a result, polymerized or cross-linked by reaction with heat or light, resulting in a high molecular weight and loss of liquid crystallinity. Preferred examples of the discotic liquid crystalline molecules are described in JP-A-8-50206. The polymerization of discotic liquid crystalline molecules is described in JP-A-8-27284.

  In order to fix the discotic liquid crystalline molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline molecules. A compound in which the discotic core and the polymerizable group are bonded via a linking group is preferable, whereby the orientation state can be maintained even in the polymerization reaction. Examples thereof include compounds described in paragraph numbers [0151] to [0168] of JP-A No. 2000-155216.

  In the hybrid alignment, the angle between the major axis (disk surface) of the discotic liquid crystalline molecule and the surface of the polarizing film increases or decreases in the depth direction of the optically anisotropic layer and with increasing distance from the surface of the polarizing film. doing. The angle preferably decreases with increasing distance. Further, the change in angle can be a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, or an intermittent change including an increase and a decrease. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if the angle includes a region where the angle does not change, the angle only needs to increase or decrease as a whole. Furthermore, it is preferable that the angle changes continuously.

  The average direction of the major axis of the discotic liquid crystalline molecules on the polarizing film side can be generally adjusted by selecting a discotic liquid crystalline molecule or an alignment film material or by selecting a rubbing treatment method. In addition, the major axis (disk surface) direction of the surface-side (air-side) discotic liquid crystalline molecules is generally adjusted by selecting the type of additive used together with the discotic liquid crystalline molecules or discotic liquid crystalline molecules. be able to. Examples of the additive used together with the discotic liquid crystalline molecule include a plasticizer, a surfactant, a polymerizable monomer and a polymer. The degree of change in the orientation direction of the major axis can also be adjusted by selecting liquid crystalline molecules and additives as described above.

(Other composition of optically anisotropic layer)
Along with the liquid crystal molecules, a plasticizer, a surfactant, a polymerizable monomer, and the like can be used in combination to improve the uniformity of the coating film, the strength of the film, the orientation of the liquid crystal molecules, and the like. It is preferable that the compound has compatibility with the liquid crystal molecules and can change the tilt angle of the liquid crystal molecules or does not inhibit the alignment.

  Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. Preferably, it is a polyfunctional radically polymerizable monomer, and the thing which shows copolymerizability with respect to the liquid crystal compound which has said polymeric group is preferable. Examples thereof include those described in paragraph numbers [0018] to [0020] of JP-A No. 2002-296423. The amount of the compound added is generally in the range of 1% by mass to 50% by mass and preferably in the range of 5% by mass to 30% by mass with respect to the discotic liquid crystalline molecules.

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specific examples include compounds described in paragraph numbers [0028] to [0056] of JP-A No. 2001-330725.

  The polymer used together with the discotic liquid crystalline molecule is preferably capable of changing the tilt angle of the discotic liquid crystalline molecule.

  Examples of the polymer include cellulose acylate. Preferable examples of cellulose acylate include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1% by mass to 10% by mass with respect to the liquid crystalline molecule so as not to inhibit the alignment of the liquid crystal molecules. It is more preferable that it is in the range.

  The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline molecules is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

(Formation of optically anisotropic layer)
The optically anisotropic layer can be formed by applying a coating liquid containing liquid crystalline molecules and, if necessary, a polymerization initiator described later and optional components on the alignment film.
As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg N, N-dimethylformamide), sulfoxides (eg dimethyl sulfoxide), heterocyclic compounds (eg pyridine), hydrocarbons (eg benzene, hexane), alkyl halides (eg , Chloroform, dichloromethane, tetrachloroethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.

The coating liquid can be applied by a known method (for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, or a die coating method).
The thickness of the optically anisotropic layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and particularly preferably 1 to 10 μm.

(Fixing alignment state of liquid crystalline molecules)
The aligned liquid crystal molecules can be fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred.

  Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (US Pat. No. 2,448,828). Description), α-hydrocarbon substituted aromatic acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (US Pat. Nos. 3,046,127 and 2,951,758). ), A combination of triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3,549,367), acridine and phenazine compound (Japanese Patent Laid-Open No. 60-105667), U.S. Pat. No. 4,239,850) and oxadiazole compounds (described in U.S. Pat. No. 4,212,970).

The amount of the photopolymerization initiator used is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 0.5 to 5% by mass, based on the solid content of the coating solution.
It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules.
The irradiation energy is preferably in the range of ^{20mJ / cm 2 ~50J / cm 2} , more preferably in the range of 20~5000mJ / cm ^2, and particularly preferably in the range of 100 to 800 mJ / cm ² . In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.
A protective layer may be provided on the optically anisotropic layer.

(Combination with polarizing film)
It is also preferable to combine this optical compensation film and a polarizing film. Specifically, the optically anisotropic layer is formed by applying the coating liquid for the optically anisotropic layer as described above to the surface of the polarizing film. As a result, without using a polymer film between the polarizing film and the optically anisotropic layer, a thin polarizing plate having a small stress (strain × cross-sectional area × elastic modulus) associated with the dimensional change of the polarizing film is produced. . When a polarizing plate using the cellulose film of the present invention is attached to a large liquid crystal display device, an image with high display quality can be displayed without causing problems such as light leakage.

  The tilt angle of the polarizing film and the optical compensation layer may be stretched so as to match the angle formed by the transmission axis of the two polarizing plates bonded to both sides of the liquid crystal cell constituting the LCD and the vertical or horizontal direction of the liquid crystal cell. preferable. A normal inclination angle is 45 °. Recently, however, devices that are not necessarily 45 ° have been developed for transmissive, reflective, and transflective LCDs, and it is preferable that the stretching direction can be arbitrarily adjusted in accordance with the design of the LCD.

[Antireflection film]
The present invention relates to an antireflection film having an antireflection layer on a cellulose body film or a retardation film.

<Applying an antireflection layer (production of an antireflection film)>
In general, the antireflection film transparently supports a low refractive index layer which is also an antifouling layer, and at least one layer having a higher refractive index than that of the low refractive index layer (ie, a high refractive index layer and a medium refractive index layer). It is provided on the body.
As a method of forming a multilayer film in which transparent thin films of inorganic compounds (metal oxides, etc.) having different refractive indexes are laminated, a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method, or a sol-gel method of a metal compound such as a metal alkoxide. Examples thereof include a method of forming a thin film after forming a colloidal metal oxide particle film by post-processing (ultraviolet irradiation: JP-A-9-157855, plasma processing: JP-A-2002-327310).

On the other hand, various antireflection films in which thin films are laminated by applying a dispersion in which inorganic particles are dispersed in a matrix have been proposed as antireflection films having high productivity. Examples of the antireflection film by application include an antireflection film in which a layer provided with an antiglare property having fine irregularities on the surface is formed on the uppermost layer.
The cellulose acylate film of the present invention can be applied to the antireflection film produced by any of the above methods, but is particularly preferably applied to the antireflection film produced by a coating method (coating type).

(Layer structure of coating type antireflection film)
An antireflection film consisting of a layer structure in which at least a middle refractive index layer, a high refractive index layer, and a low refractive index layer (outermost layer) are sequentially formed on a transparent support is designed so that the refractive index satisfies the following relationship: The
The refractive index of the high refractive index layer> The refractive index of the medium refractive index layer> The refractive index of the transparent support> The refractive index of the low refractive index layer Further, a hard coat layer is provided between the transparent support and the medium refractive index layer. May be. Further, it may be composed of a medium refractive index hard coat layer, a high refractive index layer and a low refractive index layer. Examples thereof include those described in JP-A-8-122504, JP-A-8-110401, JP-A-10-300902, JP-A-2002-243906, JP-A-2000-11706, and the like.

Other functions may be imparted to each layer, for example, an antifouling low refractive index layer or an antistatic high refractive index layer (for example, JP-A-10-206603, JP-A-2002). -243906 etc.) etc. are mentioned.
The haze of the antireflection film is preferably 5% or less, and more preferably 3% or less. Further, the strength of the film is preferably H or more, more preferably 2H or more, and particularly preferably 3H or more in a pencil hardness test according to JIS K5400.

(High refractive index layer and medium refractive index layer)
The layer having a high refractive index of the antireflection film is composed of a curable film containing at least an inorganic compound ultrafine particle having a high refractive index having an average particle size of 100 nm or less and a matrix binder.
The inorganic compound fine particles having a high refractive index include inorganic compounds having a refractive index of 1.65 or more, preferably inorganic compounds having a refractive index of 1.9 or more. Examples thereof include oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and composite oxides containing these metal atoms.

  In order to obtain such ultrafine particles, a technique for treating the surface of the particles with a surface treatment agent (for example, described in JP-A Nos. 11-295503, 11-153703, and 2000-9908). Technology that treats with a silane coupling agent, technology that treats with an anionic compound or organometallic coupling agent described in JP 2001-310432 A, etc., technology that makes a core-shell structure with high refractive index particles as a core (For example, a technique described in JP-A-2001-166104), a technique using a specific dispersant (for example, JP-A-11-153703, US Pat. No. 6,210,858B1, JP-A-2002) Technology described in Japanese Patent Application Publication No. 2776069, etc. can be used. Examples of the material forming the matrix include conventionally known thermoplastic resins and curable resin films.

Further, the composition is selected from a composition containing a polyfunctional compound having at least two radically polymerizable and / or cationically polymerizable groups, an organometallic compound having a hydrolyzable group, and a composition of a partial condensate thereof. At least one composition is preferred. Examples of the compound used in these compositions include compounds described in JP-A Nos. 2000-47004, 2001-315242, 2001-31871, and 2001-296401.
A curable film obtained from a colloidal metal oxide obtained from a hydrolyzed condensate of metal alkoxide and a metal alkoxide composition is also preferred. For example, a curable film described in JP-A No. 2001-293818 can be exemplified.

The refractive index of the high refractive index layer is generally 1.70 to 2.20. The thickness of the high refractive index layer is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm.
The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.50 to 1.70.

(Low refractive index layer)
The low refractive index layer is a layer formed by sequentially laminating on the high refractive index layer. The refractive index of the low refractive index layer is generally 1.20 to 1.55. Preferably it is 1.30-1.50.
The low refractive index layer is preferably constructed as an outermost layer having scratch resistance and antifouling properties. In order to greatly improve the scratch resistance, it is effective to impart slipperiness to the surface. Specifically, a conventionally known method for forming a thin film layer into which a silicone compound or a fluorine-containing compound is introduced can be applied. .

  The refractive index of the fluorine-containing compound is preferably 1.35 to 1.50. More preferably, it is 1.36-1.47. Moreover, it is preferable that a fluorine-containing compound is a compound containing the crosslinkable or polymerizable functional group which contains a fluorine atom in 35-80 mass%.

For example, paragraph numbers [0018] to [0026] in JP-A-9-222503, paragraph numbers [0019] to [0030] in JP-A-11-38202, and paragraph number [0027] in JP-A-2001-40284. To [0028], and compounds described in JP-A No. 2000-284102.
The silicone compound is a compound having a polysiloxane structure, and preferably has a curable functional group or a polymerizable functional group in the polymer chain and forms a crosslinked structure in the film. For example, reactive silicone (for example, Silaplane (manufactured by Chisso Corporation), polysiloxane having silanol groups at both ends (JP-A-11-258403, etc.) and the like can be mentioned.

The crosslinking or polymerization reaction of the fluorine-containing and / or siloxane polymer having a crosslinking or polymerizable group is carried out by light irradiation at the same time as or after coating the coating composition for forming the outermost layer containing a polymerization initiator or a sensitizer. It is preferable to carry out by heating or heating.
A sol-gel cured film obtained by curing a condensation reaction between an organometallic compound such as a silane coupling agent and a silane coupling agent having a specific fluorine-containing hydrocarbon group in the presence of a catalyst is also preferable.

  For example, a polyfluoroalkyl group-containing silane compound or a partially hydrolyzed condensate thereof (Japanese Patent Laid-Open Nos. 58-142958, 58-147483, 58-147484, Japanese Patent Laid-Open Nos. 9-157582, 11) -106704 and the like), silyl compounds containing a poly (perfluoroalkyl ether) group which is a fluorine-containing long chain group (Japanese Patent Application Laid-Open Nos. 2000-117902, 2001-48590, 2002-53804). Etc.) and the like.

The low refractive index layer has an average primary particle diameter of 1 to 150 nm such as a filler (for example, silicon dioxide (silica), fluorine-containing particles (magnesium fluoride, calcium fluoride, barium fluoride)) as an additive other than the above. Low refractive index inorganic compounds, organic fine particles described in paragraphs [0020] to [0038] of JP-A-11-3820, etc.), silane coupling agents, slip agents, surfactants, and the like can be contained.
When the low refractive index layer is located below the outermost layer, the low refractive index layer may be formed by a vapor phase method (vacuum deposition method, sputtering method, ion plating method, plasma CVD method, etc.). The coating method is preferable because it can be manufactured at a low cost.
The film thickness of the low refractive index layer is preferably 30 to 200 nm, more preferably 50 to 150 nm, and particularly preferably 60 to 120 nm.

(Hard coat layer)
The hard coat layer can be provided on the surface of the transparent support in order to impart physical strength to the antireflection film. In particular, it is preferably provided between the transparent support and the high refractive index layer.
The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of a light and / or heat curable compound. The curable functional group is preferably a photopolymerizable functional group, and the organometallic compound having a hydrolyzable functional group is preferably an organic alkoxysilyl compound.
Specific examples of these compounds are the same as those exemplified for the high refractive index layer.

Specific examples of the constituent composition of the hard coat layer include those described in JP-A Nos. 2002-144913, 2000-9908 and WO 00/46617.
The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form fine particles dispersed in the hard coat layer using the method described in the description of the high refractive index layer.
The hard coat layer can also serve as an antiglare layer (described later) provided with particles having an average particle size of 0.2 to 10 μm to provide an antiglare function (antiglare function).
The film thickness of the hard coat layer can be appropriately designed depending on the application. The film thickness of the hard coat layer is preferably 0.2 to 10 μm, more preferably 0.5 to 7 μm.
The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and particularly preferably 3H or higher, in a pencil hardness test according to JIS K5400. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

(Forward scattering layer)
The forward scattering layer is provided in order to give a viewing angle improvement effect when the viewing angle is inclined in the vertical and horizontal directions when applied to a liquid crystal display device. By dispersing fine particles having different refractive indexes in the hard coat layer, it can also serve as a hard coat function.

  For example, Japanese Patent Application Laid-Open No. 11-38208 specifying a forward scattering coefficient, Japanese Patent Application Laid-Open No. 2000-199809 having a relative refractive index of a transparent resin and fine particles in a specific range, and Japanese Patent Application Laid-Open No. 2002 specifying a haze value of 40% or more. The technique described in -107512 gazette etc. can be used.

(Other layers)
In addition to the above layers, a primer layer, an antistatic layer, an undercoat layer, a protective layer, and the like may be provided.

(Application method)
Each layer of the antireflection film is formed by dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, micro gravure method or extrusion coating method (US Pat. No. 2,681,294). According to the specification, it can be formed by coating.

(Anti-glare function)
The antireflection film may have an antiglare function that scatters external light. The antiglare function can be obtained by forming irregularities on the surface of the antireflection film. When the antireflection film has an antiglare function, the haze of the antireflection film is preferably 3 to 30%, more preferably 5 to 20%, and most preferably 7 to 20%.

  As a method for forming irregularities on the surface of the antireflection film, any method can be applied as long as these surface shapes can be sufficiently retained. For example, a method of forming irregularities on the film surface using fine particles in the low refractive index layer (for example, JP 2000-271878 A), a lower layer of the low refractive index layer (high refractive index layer, medium refractive index layer) Alternatively, a small amount (0.1 to 50% by mass) of relatively large particles (particle size 0.05 to 2 μm) is added to the hard coat layer to form a surface uneven film, and these shapes are maintained thereon. A method of providing a low refractive index layer (for example, JP 2000-281410 A, JP 2000-95893 A, JP 2001-100004 A, 2001-281407, etc.), an uppermost layer (antifouling layer) A method of physically transferring an uneven shape onto the surface after coating (for example, as an embossing method, JP-A-63-278839, JP-A-11-183710, JP-A-2000-275401) Wherein) and the like.

〔Polarizer〕
The polarizing plate of the present invention is a polarizing plate comprising a polarizing film and two protective films sandwiching the polarizing film, and at least one of the two protective films is a cellulose body film or a retardation film of the present invention. Or at least one of an optical compensation film and an antireflection film.

<Polarizing film>
(Polarized film material)
At present, commercially available polarizing films are generally produced by immersing a stretched polymer in a solution of iodine or dichroic dye in a bath and allowing the iodine or dichroic dye to penetrate into the binder. is there. The polarizing film is manufactured by Optiva Inc. A coating type polarizing film typified by can also be used.
Iodine and dichroic dye in the polarizing film exhibit polarizing performance by being oriented in the binder. As the dichroic dye, an azo dye, a stilbene dye, a pyrazolone dye, a triphenylmethane dye, a quinoline dye, an oxazine dye, a thiazine dye or an anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (for example, sulfo, amino, hydroxyl). For example, the compounds described in page 58 of the Japan Society for Invention Disclosure Technique (Public Technical No. 2001-1745, published on March 15, 2001, Japan Society for Invention) are mentioned.

  As the binder of the polarizing film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used. Examples of the binder include methacrylate copolymer, styrene copolymer, polyolefin, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylolacrylamide) described in paragraph No. [0022] of JP-A-8-338913, Polyester, polyimide, vinyl acetate copolymer, carboxymethyl cellulose, polycarbonate and the like are included. Silane coupling agents can be used as the polymer.

Among these, water-soluble polymers (for example, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol) are preferable, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are more preferable, and polyvinyl alcohol and modified polyvinyl alcohol are preferable. Further preferred. It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization. The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%.
It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

The modified polyvinyl alcohol is described in JP-A-8-338913, JP-A-9-152509 and JP-A-9-316127. Two or more kinds of polyvinyl alcohol and modified polyvinyl alcohol may be used in combination.
The lower limit of the binder thickness is preferably 10 μm. The upper limit of the thickness is preferably as thin as possible from the viewpoint of light leakage of the liquid crystal display device. It is preferably not more than a commercially available polarizing plate (about 30 μm), more preferably 25 μm or less, and particularly preferably 20 μm or less.

  The binder of the polarizing film may be cross-linked. A polymer or monomer having a crosslinkable functional group may be mixed in the binder, or a crosslinkable functional group may be imparted to the binder polymer itself. Crosslinking can be performed by light, heat, or pH change, and a binder having a crosslinked structure can be formed. The crosslinking agent is described in US Reissue Patent 23297. Boron compounds (for example, boric acid and borax) can also be used as a crosslinking agent. The addition amount of the crosslinking agent in the binder is preferably 0.1 to 20% by mass with respect to the binder. The orientation of the polarizing element and the wet heat resistance of the polarizing film are improved.

  After the crosslinking reaction is completed, the unreacted crosslinking agent is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By doing in this way, a weather resistance improves.

(Stretching of polarizing film)
The polarizing film is preferably dyed with iodine or a dichroic dye after the polarizing film is stretched (stretching method) or rubbed (rubbing method).
In the stretching method, the stretching ratio is preferably 2.5 to 30.0 times, and more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air. Moreover, you may implement by the wet extending | stretching in the state immersed in water. The stretch ratio of dry stretching is preferably 2.5 to 5.0 times, and the stretch ratio of wet stretching is preferably 3.0 to 10.0 times. The stretching ratio here represents (length of polarizing film after stretching / length of polarizing film before stretching). Stretching may be performed in parallel to the MD direction (parallel stretching) or may be performed in an oblique direction (oblique stretching). These stretching operations may be performed once or divided into several times. By dividing into several times, it is possible to stretch more uniformly even at high magnification. More preferred is oblique stretching in which the film is stretched with an inclination of 10 to 80 degrees in the oblique direction.

(A) Parallel stretching method Prior to stretching, the PVA film is swollen. The degree of swelling is usually 1.2 to 2.0 times (mass ratio before swelling and after swelling). Thereafter, the film is stretched at a bath temperature of usually 15 to 50 ° C., preferably 17 to 40 ° C. in an aqueous medium bath or a dye bath for dissolving a dichroic substance while being continuously conveyed through a guide roll or the like. Stretching can be performed by gripping with two pairs of nip rolls and increasing the conveyance speed of the subsequent nip rolls to be higher than that of the preceding nip rolls. The stretching ratio (after stretching / length ratio in the initial state: hereinafter the same) is preferably 1.2 to 3.5 times, more preferably 1.5 to 3.0 times from the viewpoint of the above-described effects. Thereafter, the film is dried at 50 ° C. to 90 ° C. to obtain a polarizing film.

(B) Diagonal stretching method The oblique stretching method can be carried out by stretching using a tenter projecting in an oblique direction, as described in JP-A-2002-86554. Since this stretching is performed in the air, it is necessary to make the film easy to stretch by adding water in advance. The preferred water content is 5% to 100%, more preferably 10% to 100%.
The temperature during stretching is preferably 40 ° C to 90 ° C, more preferably 50 ° C to 80 ° C. The relative humidity is preferably 50% to 100%, more preferably 70% to 100%, and particularly preferably 80% to 100%. The traveling speed in the longitudinal direction is preferably 1 m / min or more, more preferably 3 m / min or more.

After the end of stretching, the film is preferably dried at 50 ° C to 100 ° C, more preferably 60 ° C to 90 ° C, preferably 0.5 minutes to 10 minutes, more preferably 1 minute to 5 minutes.
The absorption axis of the polarizing film thus obtained is preferably 10 ° to 80 °, more preferably 30 ° to 60 °, and particularly preferably 45 ° (40 ° to 50 °).

(Lamination)
The cellulose body film after saponification and the polarizing film formed by stretching are bonded to produce a polarizing plate. The laminating direction is preferably such that the casting axis direction of the cellulosic film and the stretching axis direction of the polarizing plate are 45 °.
The adhesive for bonding is not particularly limited, but examples thereof include PVA resins (including modified PVA such as acetoacetyl group, sulfonic acid group, carboxyl group, oxyalkylene group) and boron compound aqueous solution. preferable. The thickness of the adhesive layer is preferably 0.01 to 10 μm after drying, and particularly preferably 0.05 to 5 μm.

  The polarizing plate thus obtained preferably has a higher light transmittance, and preferably has a higher degree of polarization. The transmittance of the polarizing plate is preferably in the range of 30 to 50%, more preferably in the range of 35 to 50%, and particularly preferably in the range of 40 to 50% in the light with a wavelength of 550 nm. . The degree of polarization is preferably in the range of 90 to 100%, more preferably in the range of 95 to 100%, and particularly preferably in the range of 99 to 100% in light having a wavelength of 550 nm.

  Furthermore, the polarizing plate thus obtained can be laminated with a λ / 4 plate to produce a circularly polarizing plate. In this case, lamination is performed so that the slow axis of the λ / 4 plate and the absorption axis of the polarizing plate are 45 degrees. At this time, the λ / 4 plate is not particularly limited, but a λ / 4 plate having a wavelength dependency such that the retardation becomes smaller as the wavelength becomes lower is more preferable. Furthermore, it is preferable to use a polarizing film having an absorption axis inclined by 20 ° to 70 ° with respect to the longitudinal direction and a λ / 4 plate made of an optically anisotropic layer made of a liquid crystalline compound.

(Image display device)
The present invention relates to an image display device including at least one of a cellulose body film, a retardation film, a polarizing plate, an optical compensation film, and an antireflection film.
As the image display device, a liquid crystal display device can be preferably exemplified.

<Liquid crystal display device>
The cellulose-based film of the present invention, the polarizing plate using the cellulose-based film, the retardation film and the optical film can be preferably incorporated in a liquid crystal display device. Examples of the liquid crystal display device include TN type, IPS type, FLC type, AFLC type, OCB type, STN type, ECB type, VA type and HAN type display devices. In addition, the cellulose film of the present invention can be preferably used in any of transmissive, reflective, and transflective liquid crystal display devices. Each liquid crystal mode will be described below.

(TN type liquid crystal display device)
The cellulose film of the present invention may be used as a support for an optical compensation film of a TN type liquid crystal display device having a TN mode liquid crystal cell. TN mode liquid crystal cells and TN type liquid crystal display devices have been well known for a long time. The optical compensation film used in the TN type liquid crystal display device can be produced according to the descriptions in JP-A-3-9325, JP-A-6-148429, JP-A-8-50206, and JP-A-9-26572. it can. In addition, according to the description of Mori et al. (Jpn. J. Appl. Phys. Vol. 36 (1997) p. 143 and Jpn. J. Appl. Phys. Vol. 36 (1997) p. 1068). Can be produced.

(STN type liquid crystal display device)
The cellulose-based film of the present invention may be used as a support for an optical compensation film of an STN type liquid crystal display device having an STN mode liquid crystal cell. In general, in a STN type liquid crystal display device, rod-like liquid crystalline molecules in a liquid crystal cell are twisted in the range of 90 to 360 degrees, and the refractive index anisotropy (Δn) and cell gap (d) of the rod-like liquid crystalline molecules. Product (Δnd) is in the range of 300 to 1500 nm. The optical compensation film used in the STN type liquid crystal display device can be produced according to the description in JP-A No. 2000-105316.

(VA type liquid crystal display device)
The cellulose-based film of the present invention is particularly advantageously used as a support for an optical compensation film of a VA liquid crystal display device having a VA mode liquid crystal cell. The Re value of the optical compensation film used in the VA liquid crystal display device is preferably 0 to 150 nm and the Rth value is preferably 70 to 400 nm. When two optically anisotropic polymer films are used for the VA liquid crystal display device, the Rth value of the film is preferably 70 to 250 nm. When one optically anisotropic polymer film is used for the VA liquid crystal display device, the Rth value of the film is preferably 150 to 400 nm. The VA-type liquid crystal display device may be an alignment-divided system as described in, for example, JP-A-10-123576.

(IPS liquid crystal display device, ECB liquid crystal display device)
The cellulose film of the present invention is also suitably used as an optical compensation film for an IPS liquid crystal display device or an ECB liquid crystal display device having an IPS mode or ECB mode liquid crystal cell, or as a protective film for a polarizing plate. In these modes, the liquid crystal material is aligned substantially in parallel during black display, and black is displayed by aligning liquid crystal molecules in parallel with the substrate surface in the absence of applied voltage. In these embodiments, the polarizing plate using the cellulosic film of the present invention contributes to improving the color tone, widening the viewing angle, and improving the contrast. In this aspect, the cellulose body film of the present invention was used for the protective film (the protective film on the cell side) disposed between the liquid crystal cell and the polarizing plate among the protective films of the polarizing plate above and below the liquid crystal cell. It is preferable to use a polarizing plate on at least one side. More preferably, an optically anisotropic layer is disposed between the protective film of the polarizing plate and the liquid crystal cell, and the retardation value of the disposed optically anisotropic layer is not more than twice the value of Δn · d of the liquid crystal layer. It is preferable to set to.

(OCB type liquid crystal display device, HAN type liquid crystal display device)
The cellulose film of the present invention is also advantageously used as a support for an optical compensation film of an OCB type liquid crystal display device having an OCB mode liquid crystal cell or a HAN type liquid crystal display device having a HAN mode liquid crystal cell. In the optical compensation film used for the OCB type liquid crystal display device or the HAN type liquid crystal display device, it is preferable that the direction in which the absolute value of the retardation value is minimum does not exist in the plane of the optical compensation film or in the normal direction. The optical properties of the optical compensation film used in the OCB type liquid crystal display device or the HAN type liquid crystal display device are the same as the optical properties of the optical anisotropic layer, the optical properties of the support, and the optical anisotropic layer and the support. Is determined by the arrangement of The optical compensation film used for the OCB type liquid crystal display device or the HAN type liquid crystal display device can be produced according to the description in JP-A-9-197397. It can also be prepared according to the description of Mori et al. (Jpn. J. Appl. Phys. Vol. 38 (1999) p. 2837).

(Reflective liquid crystal display)
The cellulose-based film of the present invention is also advantageously used as an optical compensation film for TN type, STN type, HAN type and GH (Guest-Host) type reflective liquid crystal display devices. These display modes have been well known since ancient times. The TN-type reflective liquid crystal display device can be manufactured according to the descriptions in JP-A-10-123478, WO98-48320 pamphlet, and Japanese Patent No. 3022477. About the optical compensation film used for a reflection type liquid crystal display device, it can produce according to description of the international publication 00-65384 pamphlet.

(Other liquid crystal display devices)
The cellulose-based film of the present invention is also advantageously used as a support for an optical compensation film of an ASM type liquid crystal display device having a liquid crystal cell of ASM (Axial Symmetrical Microcell) mode. The ASM mode liquid crystal cell is characterized in that the thickness of the cell is maintained by a resin spacer whose position can be adjusted. Other properties are the same as those of the TN mode liquid crystal cell. The ASM mode liquid crystal cell and the ASM type liquid crystal display device can be manufactured according to the description of Kume et al. (Kume et al., SID 98 Digest 1089 (1998)).

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

[Synthesis Example 1: Synthesis of Exemplary Compound A-1]
In a 3 L three-necked flask equipped with a mechanical stirrer, thermometer, condenser, and dropping funnel, 40 g of diacetylcellulose having a substitution degree of 2.15 and 400 ml of pyridine were weighed and stirred at room temperature. 100 mL of isovaleryl chloride (manufactured by Aldrich) was slowly added dropwise thereto, and the mixture was further stirred at 70 ° C. for 5 hours after the addition. After the reaction, the mixture was allowed to cool to room temperature, and the reaction solution was poured into 10 L of methanol with vigorous stirring, whereby a white solid was precipitated. The white solid was filtered off by suction filtration and washed with a large amount of methanol three times. The obtained white solid was dried at 60 ° C. overnight and then vacuum-dried at 90 ° C. for 6 hours to obtain 45 g of the intended exemplified compound A-1 as a white powder. The average degree of polymerization was 250.

[Synthesis Example 2: Synthesis of Exemplary Compound A-2]
In the production of the above exemplified compound A-1, except that isovaleryl chloride was changed to t-butylacetyl chloride (manufactured by Aldrich), 43 g of the desired exemplified compound A-2 was obtained as a white powder. . The average degree of polymerization was 258.

[Synthesis Example 3: Synthesis of Exemplary Compound A-3]
41 g of the target exemplified compound A-3 was obtained as a white powder in the same manner as in the production of the exemplified compound A-1, except that isovaleryl chloride was changed to 2-ethylbutanoyl chloride (manufactured by Aldrich). It was. The average degree of polymerization was 257.

[Synthesis Example 4: Synthesis of Comparative Compound B-1]
41 g of the target comparative compound B-1 was obtained as a white powder in the same manner as in the production of the exemplified compound A-1, except that isovaleryl chloride was changed to hexanoyl chloride (manufactured by Aldrich). The average degree of polymerization was 256.

[Synthesis Example 5: Synthesis of Exemplified Compound A-5]
41 g of the target exemplified compound A-5 was obtained as a white powder in the same manner as in the production of the exemplified compound A-1, except that 100 mL of isovaleryl chloride was changed to 50 mL. The average degree of polymerization was 256.

[Synthesis Example 6: Synthesis of Exemplified Compound A-6]
In the production of the exemplified compound A-1, 40 g of the desired exemplified compound A-6 was obtained as a white powder in the same manner except that 100 mL of isovaleryl chloride was changed to 50 mL of t-butylacetyl chloride. The average degree of polymerization was 256.

[Synthesis Example 7: Synthesis of Exemplary Compound A-7]
In the production of the exemplified compound A-1, 40 g of the desired exemplified compound A-7 was obtained as a white powder in the same manner except that 100 mL of isovaleryl chloride was changed to 50 mL of 2-ethylbutanoyl chloride. . The average degree of polymerization was 256.

[Synthesis Example 8: Synthesis of Exemplary Compound A-8]
In the production of the above exemplified compound A-1, except that 100 mL of isovaleryl chloride is changed to 50 mL of 3,5,5-trimethylhexanoyl chloride, the target exemplified compound A-8 is treated as a white powder. As a result, 40 g was obtained. The average degree of polymerization was 256.

[Synthesis Example 9: Synthesis of Comparative Compound B-2]
40 g of the intended comparative compound B-2 was obtained as a white powder in the same manner as in the production of the exemplified compound A-1, except that 100 mL of isovaleryl chloride was changed to 35 mL of butyryl chloride. The average degree of polymerization was 256.

[Synthesis Example 10: Synthesis of Comparative Compound B-3]
41 g of the target comparative compound B-3 was obtained as a white powder in the same manner as in the production of the exemplified compound A-1, except that 100 mL of isovaleryl chloride was changed to 50 mL of hexanoyl chloride. The average degree of polymerization was 256.

[Synthesis Example 11: Synthesis of Exemplary Compound A-15]
Into a 5 L three-necked flask equipped with a mechanical stirrer, thermometer, condenser, and dropping funnel, 40 g of cellulose acetate having a substitution degree of 2.15, 40 mL of pyridine, and 400 mL of acetone were weighed and stirred at room temperature. 75 mL of 2-ethylhexanoyl chloride (manufactured by Aldrich) was slowly added dropwise thereto, and the mixture was further stirred at 50 ° C. for 2 hours after the addition. After the reaction, the mixture was allowed to cool to room temperature, and the reaction solution was poured into 20 L of methanol with vigorous stirring, whereby a white solid was precipitated. The white solid was filtered off by suction filtration and washed with a large amount of methanol three times. The obtained white solid was dried at 60 ° C. overnight, and then vacuum dried at 90 ° C. for 6 hours to obtain 41 g of the intended exemplified compound A-15 as a white powder. The average degree of polymerization was 257.

[Synthesis Example 12: Synthesis of Comparative Compound B-4]
In the production of the exemplified compound A-15, 75 mL of 2-ethylhexanoyl chloride (Aldrich) was changed to 65 mL of hexanoyl chloride (Aldrich) in the same manner, and the target comparative compound B-4 Was obtained as white powder. The average degree of polymerization was 256.

[Synthesis Example 13: Synthesis of Comparative Compound B-5]
In the production of Exemplified Compound A-15, 2-ethylhexanoyl chloride (manufactured by Aldrich) was changed to octanoyl chloride (manufactured by Aldrich) in the same manner, and the target comparative compound B-5 was converted into white powder. 42g was obtained as a body. The average degree of polymerization was 257.

[Synthesis Example 14: Synthesis of Exemplified Compound A-16]
In the production of the exemplified compound A-1, except that 100 mL of isovaleryl chloride is changed to 80 mL of 2-ethylhexanoyl chloride, diacetyl cellulose having a substitution degree of 2.15 is changed to acetyl cellulose having a substitution degree of 2.44. Similarly, 41 g of the target exemplified compound A-16 was obtained as a white powder. The average degree of polymerization was 258.

[Synthesis Example 15: Synthesis of Comparative Compound B-6]
In the production of the exemplified compound A-1, the same procedure except that 100 mL of isovaleryl chloride is changed to 70 mL of hexanoyl chloride, diacetyl cellulose having a substitution degree of 2.15 is changed to acetyl cellulose having a substitution degree of 2.44. 42 g of the target comparative compound B-6 was obtained as a white powder. The average degree of polymerization was 256.

[Synthesis Example 16: Synthesis of Comparative Compound B-7]
In the production of the above exemplified compound A-1, except that 100 mL of isovaleryl chloride is changed to 80 mL of octanoyl chloride, diacetyl cellulose having a substitution degree of 2.15 is changed to acetyl cellulose having a substitution degree of 2.44. 42 g of the target comparative compound B-7 was obtained as a white powder. The average degree of polymerization was 256.

[Synthesis Example 17: Synthesis of Exemplary Compound A-17]
In the production of the exemplified compound A-1, except that 100 mL of isovaleryl chloride is changed to 30 mL of 2-ethylhexanoyl chloride, diacetyl cellulose having a substitution degree of 2.15 is changed to acetyl cellulose having a substitution degree of 2.80. Similarly, 41 g of the target exemplified compound A-17 was obtained as a white powder. The average degree of polymerization was 258.

[Synthesis Example 18: Synthesis of Comparative Compound B-8]
In the production of the exemplified compound A-1, the same procedure was performed except that 100 mL of isovaleryl chloride was changed to 25 mL of hexanoyl chloride, diacetyl cellulose having a substitution degree of 2.15 was changed to acetyl cellulose having a substitution degree of 2.80. 42 g of the target comparative compound B-8 was obtained as a white powder. The average degree of polymerization was 256.

[Synthesis Example 19: Synthesis of Exemplary Compound A-18]
In the production of the exemplified compound A-1, except that 100 mL of isovaleryl chloride is changed to 30 mL of 2-ethylhexanoyl chloride, diacetyl cellulose having a substitution degree of 2.15 is changed to acetyl cellulose having a substitution degree of 2.93. Similarly, 43g of target exemplary compound A-18 was obtained as white powder. The average degree of polymerization was 258.

[Synthesis Example 20: Synthesis of Comparative Compound B-9]
46 g of the target comparative compound B-9 was obtained as a white powder in the same manner as in the production of the exemplified compound A-1, except that isovaleryl chloride was changed to lauryl chloride (manufactured by Aldrich). The average degree of polymerization was 250.

[Synthesis Example 21: Synthesis of Comparative Compound B-10]
43 g of the target comparative compound B-10 was obtained as a white powder in the same manner as in the production of the exemplified compound A-1, except that 100 mL of isovaleryl chloride was changed to 50 mL of lauryl chloride. The average degree of polymerization was 250.

[Example 1]
<Preparation of cellulose body solution>
The following raw materials were put into a mixing tank, stirred while heating, dissolved, and a solution having a cellulose body was prepared.

(Composition of cellulose body solution)
Cellulose acetate with a substitution degree of 2.80 100 parts by weight Methylene chloride (first solvent) 402 parts by weight Methanol (second solvent) 60 parts by weight

<Preparation of Cellulose Film Samples S-1 to 38>
562 parts by mass of the cellulose body solution was cast using a band casting machine. A film having a residual solvent amount of 15% by mass was stretched by 30% using a tenter under the condition of 160 ° C. to produce a film sample S-38 (comparative example, thickness: 80 μm).
Further, in the preparation of the cellulose body solution, films S-1, S-2, S-3, S- were prepared by the same production method except that cellulose acetate having a substitution degree of 2.80 was changed to the cellulose ester described in Table 2 below. 4, S-5, S-6, S-7, S-8, S-9, S-10, S-11, S-12, S-25 to S-32, S-34, S-37, S-38 was produced. All of these films have a thickness of 80 μm.

  A part (120 mm × 120 mm) of each film sample obtained above was taken out, and the retardation value was measured by “KOBRA 21ADH” (manufactured by Oji Scientific Instruments) at a wavelength of 590 nm at 25 ° C. and 60% RH. Re and Rth were measured. Furthermore, ΔRe and ΔRth, which are the difference between Re and Rth for light with a wavelength of 590 nm at 25 ° C. and 80% RH and Re and Rth for light with a wavelength of 590 nm at 25 ° C. and 10% RH, were measured. The results are shown in Table 2 below.

  As can be seen from the results in Table 2, it can be seen that the stretched film samples obtained from the conventional cellulose acylate and the comparative example express very small Re, Rth or negative Re, Rth. On the other hand, it can be seen that the stretched film of the present invention expresses positive Re and Rth and has improved humidity dependency. In addition, Comparative Examples S-4 and S-5 into which a long chain acyl group was introduced had a low Tg, and therefore, there was a lot of unevenness during film production, and optical property evaluation was not achieved. From the above, it can be seen that the branched acyl structure of the present invention is useful for reducing the humidity dependency of retardation while maintaining an appropriate Tg.

[Example 2: Polarizing plate protective film]
Sample of Example 1 (Films S-1, S-2, S-3, S-7, S-8, S-9, S-10, S-25, S-28, S-31, S-34 ) Were used to prepare and evaluate elliptically polarizing plate samples 001 to 011 by the method described in Example 1 of JP-A-11-316378. The optical properties of the elliptically polarizing plate obtained from the cellulose film of the present invention were excellent.

[Example 3: Liquid crystal display device]
An optical system including the polarizing plate described in Example 1 of JP-A-10-48420 and the discotic liquid crystal molecules described in Example 1 of JP-A-9-26572 using the samples 001 to 011 of Example 2. An anisotropic layer, an alignment film coated with polyvinyl alcohol, a VA type liquid crystal display device described in FIGS. 2 to 9 of JP 2000-154261 A, and an OCB described in FIGS. 10 to 15 of JP 2000-154261 A A HAN type liquid crystal display device was fabricated and evaluated. In the device obtained using the cellulose body film of the present invention, good performance was obtained in any case.

Claims (11)

A branched structure seen including, cellulosic substance containing cellulose having an aliphatic acyl group of 30 carbon atoms from 5 carbon atoms represented by the following general formula (2) (including mosquitoes carbonyl carbon of the acyl group) (A) Composition.
General formula (2)

(In the general formula (2) represents R ^4, R ^5, R ^6, R ⁷ and R ⁸ each independently represent a hydrogen atom or aralkyl kill group. However, of R ^6, R ⁷ and R ^8, at least 2 Is an alkyl group, where the part * represents a bond to the cellulose skeleton.) The cellulose body composition according to claim 1, wherein the cellulose body satisfies the following formula (I).
Formula (I): 0.1 ≦ DSA <1.54 (wherein DSA represents the degree of substitution of the acyl group (A) substituting the hydrogen atom of the hydroxyl group of cellulose) The cellulose body composition according to claim 1 or 2 , wherein the cellulose body further has an aliphatic acyl group (B) having 2 to 4 carbon atoms and satisfies the following formula (II).
Formula (II): 2.0 ≦ DSA + DSB ≦ 3.0 (In Formula (II), DSA represents the substitution degree of the acyl group (A) substituting the hydrogen atom of the hydroxyl group of cellulose, and DSB represents the acyl group ( Represents the degree of substitution of B).) The cellulose composition according to claim 3 , wherein the acyl group (B) is an acetyl group. The acyl group (A) cellulose composition according to any one of claims 1 to 4 which is 2-ethyl hexanoyl group or t- butyl acetyl group. The cellulose body film formed with the cellulose body composition of any one of Claims 1-5. A retardation film comprising the cellulose film according to claim 6 . An optical compensation film having an optically anisotropic layer formed by aligning a liquid crystalline compound on the cellulose body film according to claim 6 or the retardation film according to claim 7 . An antireflection film having an antireflection layer on the cellulose body film according to claim 6 or the retardation film according to claim 7 . A polarizing plate comprising a polarizing film and two protective films sandwiching the polarizing film, wherein at least one of the two protective films is the cellulose body film according to claim 6 , and the rank according to claim 7. A polarizing plate comprising at least one of a phase difference film, an optical compensation film according to claim 8, and an antireflection film according to claim 9 . Cellulosic substance film according to claim 6, the phase difference film according to claim 7, the optical compensation film of claim 8, antireflection film according to claim 9, one of the polarizing plate according to claim 10 An image display device including at least one of these.