JP2008149577A - Sheet, laminate, polarization plate, liquid crystal display device, and manufacturing thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide a film for optical compensation without requiring a troublesome step, provide a sheet capable of forming the film for optical compensation by a transfer method which does not cause damage to an optical device component, provide the film for optical compensation which contains cellulose N-substituted carbamate and the value represented by (n<SB>x</SB>+n<SB>y</SB>)/2-n<SB>z</SB>(where: n<SB>x</SB>: the maximum one of the refraction index in the surface of the film, n<SB>y</SB>: the minimum one, n<SB>z</SB>: the refraction index in the thickness direction) is negative, and provide the laminated body manufactured by using the film. <P>SOLUTION: The sheet is characterized in that it has the film containing cellulose N-substituted carbamate on a peelable substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet on which a film that can be suitably used for an optical device such as a liquid crystal display device can be formed by transfer. Or it is related with the laminated body which transferred the film | membrane on this sheet | seat, and also the polarizing plate and liquid crystal display device using this. Or it is related with the manufacturing method of a laminated body.

  Various optical devices such as liquid crystal display devices use various films together with a liquid crystal cell, a polarizer, etc. (in this application, a film is a layer formed directly on another substrate, which is peeled off from the substrate) And a film formed by direct solution casting, melt casting, etc.). In particular, a film for optical compensation for compensating birefringence caused by other components in the apparatus is generally used (for example, for use in applications such as widening the viewing angle and preventing color leakage during black display). Is). As a material for forming such a film for optical compensation, for example, a polymer such as polycarbonate, polyester, polystyrene, polyamide, polyimide, polyethersulfone, etc. is used. ), A stretching process (phase difference imparting), and a bonding process. However, these methods require complicated steps such as film formation and stretching, and a simple method has been demanded. Furthermore, when the retardation is applied by stretching in the thickness direction of the film (stretching by shrinking the shrinkable film, etc.), the width of the film becomes narrow, so that a wide product having equivalent performance is manufactured. A method was also sought.

In order to solve these problems, a thin film forming method in which a polyimide paste is applied has been proposed (see, for example, Patent Document 1). However, this method _{is <although} it is possible to form a system having the optical properties of _{n x = n y, n z} > n z those with optical properties of _{n x} ≧ _{n y,} in other words, [ It was not possible to form a film having a negative thickness retardation value represented by (n _x + _ny ) / 2− _nz ] × d.

On the other hand, a polymer compound solution having a functional group capable of photoisomerization is applied, dried, and then irradiated with light to control the orientation of the polymer, or a liquid crystal polymer solution or a liquid crystal polymer melt the coating, after drying, to align the liquid crystal was heat-treated at the glass transition temperature of the polymer, by fixing the orientation by cooling, to form a film having an optical property of n _z> n _x ≧ n _y (For example, refer to Patent Document 2).

  However, in these methods, compared to the formation of a retardation layer by applying a polyimide paste, when a polymer compound having a functional group capable of photoisomerization is used, light irradiation must be performed, and a liquid crystal polymer is used. In some cases, the liquid crystal is generally expensive, resulting in a high cost.

Further, in the film formation by coating and drying as described above, the solvent at the time of coating and the temperature (heat) at the time of drying may damage the optical device constituent members, and improvement is desired.
JP 2001-290023 A JP-A-7-13022

An object of the present invention is to provide an optical compensation film at a low cost without requiring a complicated process and to form an optical compensation film by a transfer method that does not damage optical device components. Is to provide a secure sheet. Furthermore, it provides a film for optical compensation containing cellulose N-substituted carbamate and having a negative value represented by (n _x + _ny ) / 2- _nz , and a laminate produced using the film Is to provide.

  In order to solve such a problem, the present inventors have been able to solve the above problem by a sheet characterized by having a film comprising cellulose N-substituted carbamate on a peelable substrate as a result of intensive studies. And found the present invention.

That is, the present invention
A sheet comprising a film containing cellulose N-substituted carbamate on a peelable substrate is provided (claim 1).

The maximum one of n _x of the in-plane refractive index of claim 1 wherein the _film, the smallest ones and n _y, the refractive index n _z in the thickness _direction, when the film thickness is d, the following The sheet according to claim 1, wherein Formula 1 is satisfied (claim 2).

[(N _x + n _y ) / 2−n _z ] × d <0 (Formula 1)
In the cellulose N-substituted carbamate, at least one hydroxyl group of cellulose is N-substituted carbamate, and at least one hydrogen atom bonded to a nitrogen atom of the carbamate group is represented by the following general formulas (1) to ( 3) (substituent bonded to N), and the substituents bonded to N of the plurality of N-substituted carbamate groups are the same or different and are represented by the following general formulas (1) to ( The sheet according to any one of claims 1 and 2, wherein the sheet is a group selected from 3) (claim 3).

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or 1 to 20 carbon atoms. Halogenated alkyl groups, C6-C20 aryl groups, C6-C20 aryloxy groups, C7-C20 aralkyl groups, C7-C20 aralkyloxy groups, C1-C21 Represents an acyloxy group, a halogen atom, or a nitro group.)

(Wherein R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Represents a halogenated alkyl group having 1 to 20 carbon atoms, an acyloxy group having 1 to 21 carbon atoms, a halogen atom, or a nitro group.)

(In the formula, R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Represents a halogenated alkyl group having 1 to 20 carbon atoms, an acyloxy group having 1 to 21 carbon atoms, a halogen atom, or a nitro group.)
In addition, an adhesive sheet is provided in which an adhesive layer is provided on the film surface of the sheet according to any one of claims 1 to 3 (claim 4).

  Moreover, after adhering the adhesive sheet according to claim 4 to at least one surface of the translucent substrate via an adhesive layer, a method for producing a laminate is provided, wherein the peelable substrate is peeled off. (Claim 5).

  Moreover, the said translucent board | substrate is a film which has controlled birefringence, The manufacturing method of the laminated body of Claim 5 characterized by the above-mentioned (Claim 6) is provided.

  The method for producing a laminate according to claim 6, wherein the film having controlled birefringence is a film made of a material having positive birefringence (Claim 7). ).

  Moreover, the laminated body manufactured using the method of Claim 5 thru | or 7 is provided (Claim 8).

  In addition, a polarizing plate is provided in which the laminate according to claim 8 is mounted on at least one surface of the polarizer as a protective material for the polarizer (claim 9).

  Moreover, the liquid crystal display device provided with the 1 or more structure chosen from the laminated body of Claim 8, and the polarizing plate of Claim 9 is provided (Claim 10).

When the sheet of the present invention is used, a complicated process is not required, and an optical compensation film can be formed without damaging the optical device constituent members. In addition, a laminate having the optical compensation film can be produced, and in particular, a laminate having an optical compensation layer of [(n _x + _ny ) / 2− _nz ] × d <0 can be produced industrially. Very useful.

  Hereinafter, the present invention will be described in detail.

  In the present invention, the alkyl group having 1 to 20 carbon atoms is, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, isobutyl group, n-pentyl group. N-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, cyclopentyl group, cyclohexyl group and the like.

  Examples of the alkoxy group having 1 to 20 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentyloxy group, and an n-hexyloxy group. Can be given.

  Examples of the halogenated alkyl group having 1 to 20 carbon atoms include fluoromethyl group, difluoromethyl group, trifluoromethyl group, chloromethyl group, dichloromethyl group, trichloromethyl group, bromomethyl group, dibromomethyl group, tribromomethyl group, 2-fluoroethyl group, 2,2-difluoroethyl group, 2,2,2-trifluoroethyl group, 2-chloroethyl group, 2,2-dichloroethyl group, 2,2,2-trichloroethyl group, 2- Examples include bromoethyl group, 2,2-dibromoethyl group, 2,2,2-tribromoethyl group, and the like.

  Examples of the aryl group having 6 to 20 carbon atoms include phenyl group, 2-tolyl group, 3-tolyl group, 4-tolyl group, xylyl group, naphthyl group, and biphenylyl group.

  Examples of the aryloxy group having 6 to 20 carbon atoms include a phenoxy group, a 2-tolyloxy group, a 3-tolyloxy group, a 4-tolyloxy group, a xylyloxy group, a naphthyloxy group, and a biphenylyloxy group.

  Examples of the aralkyl group having 7 to 20 carbon atoms include a benzyl group and a phenethyl group.

  Examples of the aralkyloxy group having 7 to 20 carbon atoms include a benzyloxy group and a phenethyloxy group.

  Examples of the acyloxy group having 1 to 21 carbon atoms include an acetoxy group, a propionyloxy group, and a benzoyloxy group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  The cellulose N-substituted carbamate used in the present invention (hereinafter sometimes referred to as component (A)) is made from cellulose obtained from, for example, various wood pulps, cotton linters, cotton lints, and the like, and bases such as pyridine and triethylamine. It can be produced by a known method in which an isocyanate compound is reacted in the presence of a catalyst (see, for example, JP-A-62-64801). In addition, by subjecting the reaction product to partial hydrolysis with an alkali such as sodium hydroxide or potassium hydroxide, one having a controlled N-substituted carbamate conversion rate can be produced. In addition, the base catalyst used at the time of the said reaction can also be used as a solvent. As other solvents at the time of synthesis, amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide can be suitably used. Furthermore, an inorganic salt such as lithium chloride can be added to improve the solubility of cellulose in a solvent. Examples of the isocyanate compound include compounds represented by the following general formulas (4) to (6).

(In the formula, R ²⁰ , R ²¹ , R ²² , R ²³ and R ²⁴ are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or 1 to 20 carbon atoms. Halogenated alkyl groups, C6-C20 aryl groups, C6-C20 aryloxy groups, C7-C20 aralkyl groups, C7-C20 aralkyloxy groups, C1-C21 Represents an acyloxy group, a halogen atom, or a nitro group.)

(In the formula, R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ , R ³¹ are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Represents a halogenated alkyl group having 1 to 20 carbon atoms, an acyloxy group having 1 to 21 carbon atoms, a halogen atom, or a nitro group.)

(Wherein R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ³⁷ , R ³⁸ are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Represents a halogenated alkyl group having 1 to 20 carbon atoms, an acyloxy group having 1 to 21 carbon atoms, a halogen atom, or a nitro group.)
These isocyanate compounds may be used alone or in combination of two or more.

In the present invention, R ²⁰ , R ²¹ , R ²² , R ²³ , and R ²⁴ are the same or different from the viewpoint of availability of the isocyanate compound, and are a hydrogen atom, an alkyl group having 1 to 16 carbon atoms, or a carbon number. An alkoxy group having 1 to 16 carbon atoms, a halogenated alkyl group having 1 to 16 carbon atoms, an aryl group having 6 to 16 carbon atoms, an aryloxy group having 6 to 16 carbon atoms, an aralkyl group having 7 to 16 carbon atoms, and 7 to 7 carbon atoms The isocyanate compound represented by the general formula (4), which is 16 aralkyloxy group, acyloxy group having 1 to 17 carbon atoms, halogen atom or nitro group, is reacted, and at least one hydroxyl group of the cellulose is N-substituted. carbamate of cellulose N- substituted carbamate or ^{R 25, R 26, R 27} , R 28, R 29, R 30, R 31, R 32, R 33, R ^{4, R 35, R 36,} R 37, R 38 are the same or different, a hydrogen atom, an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, alkyl halides having 1 to 16 carbon atoms Group, an acyloxy group having 1 to 17 carbon atoms, a halogen atom, and a nitro group are reacted with an isocyanate compound represented by general formulas (5) and (6), and at least one hydroxyl group of the cellulose is N-substituted. It is preferred to use a carbamateized cellulose N-substituted carbamate. R ²⁰ , R ²¹ , R ²² , R ²³ , R ²⁴ are the same or different and are a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a halogenated group having 1 to 12 carbon atoms. An alkyl group, an aryl group having 6 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aralkyloxy group having 7 to 12 carbon atoms, an acyloxy group having 1 to 13 carbon atoms, It is more preferable to use a cellulose N-substituted carbamate in which an isocyanate compound represented by the general formula (4) which is a halogen atom or a nitro group is reacted and at least one of the hydroxyl groups of the cellulose is N-substituted carbamate. . Or R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ , R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ³⁷ , R ³⁸ are the same or different and hydrogen General formula which is an atom, a C1-C12 alkyl group, a C1-C12 alkoxy group, a C1-C12 halogenated alkyl group, a C1-C13 acyloxy group, a halogen atom, and a nitro group It is more preferable to use a cellulose N-substituted carbamate in which the isocyanate compound represented by (5) or (6) is reacted and at least one of the hydroxyl groups of the cellulose is N-substituted carbamate.

  Specific examples of the isocyanate compounds represented by the general formulas (4) to (6) include phenyl isocyanate, o-tolyl isocyanate, m-tolyl isocyanate, p-tolyl isocyanate, 2-ethylphenyl isocyanate, 3-ethyl. Phenyl isocyanate, 4-ethylphenyl isocyanate, 2-propylphenyl isocyanate, 3-propylphenyl isocyanate, 4-propylphenyl isocyanate, 2-butylphenyl isocyanate, 3-butylphenyl isocyanate, 4-butylphenyl isocyanate, 2,3-dimethyl Phenyl isocyanate, 2,4-dimethylphenyl isocyanate, 2,5-dimethylphenyl isocyanate, 2,6-dimethylphenyl isocyanate, 3,4-dimethylphenol Nyl isocyanate, 3,5-dimethylphenyl isocyanate, 2,3-diethylphenyl isocyanate, 2,4-diethylphenyl isocyanate, 2,5-diethylphenyl isocyanate, 2,6-diethylphenyl isocyanate, 3,4-diethylphenyl isocyanate 3,5-diethylphenyl isocyanate, 2,4,6-trimethylphenyl isocyanate, 2-methoxyphenyl isocyanate, 3-methoxyphenyl isocyanate, 4-methoxyphenyl isocyanate, 2-ethoxyphenyl isocyanate, 3-ethoxyphenyl isocyanate, 4 -Ethoxyphenyl isocyanate, 2- (fluoromethyl) phenyl isocyanate, 3- (fluoromethyl) phenyl isocyanate, 4- (full (Romethyl) phenyl isocyanate, 2- (chloromethyl) phenyl isocyanate, 3- (chloromethyl) phenyl isocyanate, 4- (chloromethyl) phenyl isocyanate, 2- (bromomethyl) phenyl isocyanate, 3- (bromomethyl) phenyl isocyanate, 4- (Bromomethyl) phenyl isocyanate, 2- (iodomethyl) phenyl isocyanate, 3- (iodomethyl) phenyl isocyanate, 4- (iodomethyl) phenyl isocyanate, 2- (difluoromethyl) phenyl isocyanate, 3- (difluoromethyl) phenyl isocyanate, 4- (Difluoromethyl) phenyl isocyanate, 2- (dichloromethyl) phenyl isocyanate, 3- (dichloromethyl) phenyl isocyanate, 4- (dichloromethyl) phenyl isocyanate, 2- (dibromomethyl) phenyl isocyanate, 3- (dibromomethyl) phenyl isocyanate, 4- (dibromomethyl) phenyl isocyanate, 2- (diiodomethyl) phenyl isocyanate, 3- (diiodomethyl) phenyl Isocyanate, 4- (diiodomethyl) phenyl isocyanate, 2- (trifluoromethyl) phenyl isocyanate, 3- (trifluoromethyl) phenyl isocyanate, 4- (trifluoromethyl) phenyl isocyanate, 2- (trichloromethyl) phenyl isocyanate, 3 -(Trichloromethyl) phenyl isocyanate, 4- (trichloromethyl) phenyl isocyanate, 2- (tribromomethyl) phenyl isocyanate, 3 (Tribromomethyl) phenyl isocyanate, 4- (tribromomethyl) phenyl isocyanate, 2- (triiodomethyl) phenyl isocyanate, 3- (triiodomethyl) phenyl isocyanate, 4- (triiodomethyl) phenyl isocyanate, 2- Biphenylyl isocyanate, 3-biphenylyl isocyanate, 4-biphenylyl isocyanate, 2-phenoxyphenyl isocyanate, 3-phenoxyphenyl isocyanate, 4-phenoxyphenyl isocyanate, 2′-benzylphenyl isocyanate, 3′-benzylphenyl isocyanate, 4 ′ -Benzylphenyl isocyanate, 2-benzyloxyphenyl isocyanate, 3-benzyloxyphenyl isocyanate, 4-benzyloxyphenyl Nyl isocyanate, 2-acetoxyphenyl isocyanate, 3-acetoxyphenyl isocyanate, 4-acetoxyphenyl isocyanate, 2-fluorophenyl isocyanate, 3-fluorophenyl isocyanate, 4-fluorophenyl isocyanate, 2-chlorophenyl isocyanate, 3-chlorophenyl isocyanate, 4 -Chlorophenyl isocyanate, 2-bromophenyl isocyanate, 3-bromophenyl isocyanate, 4-bromophenyl isocyanate, 2-iodophenyl isocyanate, 3-iodophenyl isocyanate, 4-iodophenyl isocyanate, 2,4-difluorophenyl isocyanate, 2, 5-difluorophenyl isocyanate, 2,6-difluorophenyl isocyanate 3,4-difluorophenyl isocyanate, 3,5-difluorophenyl isocyanate, 2,4-dichlorophenyl isocyanate, 2,5-dichlorophenyl isocyanate, 2,6-dichlorophenyl isocyanate, 3,4-dichlorophenyl isocyanate, 3,5- Dichlorophenyl isocyanate, 2,4-dibromophenyl isocyanate, 2,5-dibromophenyl isocyanate, 2,6-dibromophenyl isocyanate, 3,4-dibromophenyl isocyanate, 3,5-dibromophenyl isocyanate, 2,4-diiodophenyl Isocyanate, 2,5-diiodophenyl isocyanate, 2,6-diiodophenyl isocyanate, 3,4-diiodophenyl isocyanate, 3,5-diiod Phenyl isocyanate, 2,3,4-trifluorophenyl isocyanate, 2,3,4-trichlorophenyl isocyanate, 2,3,4-tribromophenyl isocyanate, 2,3,4-triiodophenyl isocyanate, 2-fluoro- 5-methylphenyl isocyanate, 2-fluoro-6-methylphenyl isocyanate, 3-fluoro-2-methylphenyl isocyanate, 3-fluoro-4-methylphenyl isocyanate, 4-fluoro-2-methylphenyl isocyanate, 4-fluoro- 3-methylphenyl isocyanate, 5-fluoro-2-methylphenyl isocyanate, 2-chloro-5-methylphenyl isocyanate, 2-chloro-6-methylphenyl isocyanate, 3-chloro-2-methylphenol Isocyanate, 3-chloro-4-methylphenyl isocyanate, 4-chloro-2-methylphenyl isocyanate, 4-chloro-3-methylphenyl isocyanate, 5-chloro-2-methylphenyl isocyanate, 2-bromo-5-methyl Phenyl isocyanate, 2-bromo-6-methylphenyl isocyanate, 3-bromo-2-methylphenyl isocyanate, 3-bromo-4-methylphenyl isocyanate, 4-bromo-2-methylphenyl isocyanate, 4-bromo-3-methyl Phenyl isocyanate, 5-bromo-2-methylphenyl isocyanate, 2-iodo-5-methylphenyl isocyanate, 2-iodo-6-methylphenyl isocyanate, 3-iodo-2-methylphenyl isocyanate, 3- Iodo-4-methylphenyl isocyanate, 4-iodo-2-methylphenyl isocyanate, 4-iodo-3-methylphenyl isocyanate, 5-iodo-2-methylphenyl isocyanate, 2-nitrophenyl isocyanate, 3-nitrophenyl isocyanate, 4-nitrophenyl isocyanate, 1-naphthyl isocyanate, 2-naphthyl isocyanate, 1-methyl-2-naphthyl isocyanate, 2-methyl-1-naphthyl isocyanate, 1-methoxy-2-naphthyl isocyanate, 2-methoxy-1-naphthyl Isocyanate, 1- (trifluoromethyl) -2-naphthyl isocyanate, 2- (trifluoromethyl) -1-naphthyl isocyanate, 1- (trichloromethyl) -2-naphthyl isocyanate 2- (trichloromethyl) -1-naphthyl isocyanate, 1- (tribromomethyl) -2-naphthyl isocyanate, 2- (tribromomethyl) -1-naphthyl isocyanate, 1- (triiodomethyl) -2-naphthyl isocyanate 2- (triiodomethyl) -1-naphthyl isocyanate, 1-acetoxy-2-naphthyl isocyanate, 2-acetoxy-1-naphthyl isocyanate, 1-fluoro-2-naphthyl isocyanate, 2-fluoro-1-naphthyl isocyanate, 1-chloro-2-naphthyl isocyanate, 2-chloro-1-naphthyl isocyanate, 1-bromo-2-naphthyl isocyanate, 2-bromo-1-naphthyl isocyanate, 1-iodo-2-naphthyl isocyanate, 2-iodo-1 -Naphth Isocyanate, 1-nitro-2-naphthyl isocyanate, 2-nitro-1-naphthyl isocyanate, and the like. The cellulose N-substituted carbamates obtained by reacting these and the isocyanate compounds may be used alone or in combination of two or more.

  Cellulose has three hydroxyl groups per glucose residue, which is its structural unit. Therefore, when these hydroxyl groups are substituted, the degree of substitution per glucose residue (hereinafter referred to as DS) is 3 at maximum. In the present invention, the lower limit of DS is preferably 0.05, more preferably 1.0, still more preferably 1.9, and the upper limit is preferably 3, more preferably 2.95, and even more preferably 2.9. It is. When DS is lower than 0.05, for example, when forming a film for optical compensation by solution casting, it tends to be difficult to dissolve in a solvent. In the present invention, two or more cellulose N-substituted carbamates having different DSs may be used in combination, or may be used alone.

  Furthermore, the lower limit of the number average molecular weight of the component (A) is preferably 5000, more preferably 8000, and still more preferably 10,000, and the upper limit is preferably 500,000, more preferably 300,000, still more preferably 200,000. When the number average molecular weight is less than 5,000, the strength of the film tends to decrease, and when the number average molecular weight is more than 500,000, the film tends to be hardly soluble in a solvent (hereinafter sometimes referred to as component (B)). The number average molecular weight is a value measured by a gel permeation chromatography (GPC) method. In the present invention, two or more cellulose N-substituted carbamates having different number average molecular weights may be used in combination, or may be used alone.

  Hereinafter, the sheet of the present invention (in the present application, the sheet refers to a thin plate regardless of the thickness) will be described. This sheet | seat has a film | membrane formed by containing the said cellulose N-substituted carbamate on a peelable board | substrate. Examples of the film forming method include a method of solution casting on the substrate, a melt casting method of the substrate using an extruder or the like, and the like. A solution casting method is preferred because of the simplicity of the film formation method. As a specific example of the method by solution casting, a coating liquid for forming a film (hereinafter sometimes simply referred to as a coating liquid) is prepared, applied to the substrate, and then dried or applied. And a method of annealing and drying after coating on the substrate.

  Next, the film forming coating solution will be described. The coating liquid contains (A) the cellulose N-substituted carbamate and (B) a solvent in which the component (A) can be dissolved.

The solvent for the component (B) is not particularly limited as long as the component (A) is soluble. Specific examples include benzene, toluene, o-xylene, m-xylene, and p-xylene. Hydrocarbon solvents such as isomer mixtures of ethylbenzene, isopropylbenzene and diethylbenzene; methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, furfuryl alcohol, Alcohol solvents such as benzyl alcohol; ethyl ether, isopropyl ether, 1,3-dioxolane, 1,4-dioxane, tetrahydropyran, tetrahydrofuran, 1,2-dimethoxyethane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol Ether solvents such as coal monopropyl ether and ethylene glycol monobutyl ether; ketone solvents such as acetone, 2-butanone, 4-methyl-2-pentanone and cyclohexanone; methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, hexachloroethane, 1-chloropropane, 2 -Chloropropane, 1,1-dichloropropane, 1,2-dichloropropane, 1,3-dichloropropane, 2,2-dichloropropane, 1,2,3-trichloropropane, chlorobenzene, 1,2-dichlorobenzene, 1 , 3-Dichlorobenzene, 1,4-dichloro Halogen solvents such as benzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n acetate -Butyl, isobutyl acetate, sec-butyl acetate, tert-butyl acetate, n-pentyl acetate, n-hexyl acetate, n-heptyl acetate, n-octyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene Ester solvents such as glycol monopropyl ether acetate and ethylene glycol monobutyl ether acetate; amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and 1-methyl-2-pyrrolidinone; pyrrolidine, piperi Examples thereof include amine solvents such as gin and pyrrole. Among these, ether solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether have an absolute value represented by (n _x + _ny ) / 2− _nz. This is preferable because the value can be easily increased, that is, the absolute value of the thickness retardation can be easily increased with a thinner film. Further, from the viewpoint of easily reducing the haze of the film, ester solvents, particularly n-butyl acetate, n-pentyl acetate, and n-hexyl acetate are preferable. These solvents may be used alone or in combination of two or more.

  In the present invention, the amount of the solvent is preferably such that the ratio of the component (A) to the total weight of the components (A) and (B) is 1% by weight lower limit and 70% by weight upper limit, 2% by weight lower limit, More preferably, the upper limit is 60% by weight, and the lower limit is 3% by weight and the upper limit is 50% by weight. When the proportion of the component (A) is less than 1% by weight, the coating film thickness tends to be thin and the required film thickness tends to be difficult to obtain, and when it is greater than 70% by weight, the viscosity of the coating liquid increases. , Workability tends to be inferior.

  Next, the formation method of the coating film using the said coating liquid on a peelable board | substrate is demonstrated. The coating film can be suitably prepared on a peelable substrate by applying a coating liquid on one or both sides of the substrate to form a coated substrate, and then drying the coated substrate. As coating methods, gravure roll coating method, Mayer bar coating method, doctor blade coating method, reverse roll coating method, dip coating method, air knife coating method, calendar coating method, skies coating method, kiss coating method, bar coating method , Slot die coating method, spin coating method and the like.

  As a drying method, the coated substrate is left (air dried) in an inert gas such as air or nitrogen, a method of heat drying in a hot air oven, an infrared heating furnace, or the like, and vacuum drying with a vacuum dryer or the like. It can carry out by the method to carry out, etc. or combining these.

As the drying temperature condition, either constant temperature or multistage temperature increase can be used. In the case of constant temperature, a temperature range of a lower limit of −30 ° C. and an upper limit of 300 ° C. is preferable, a lower limit of 0 ° C. and an upper limit of 280 ° C. are more preferable, and a lower limit of 10 ° C. and an upper limit of 260 ° C. are more preferable. When the drying temperature is lower than −30 ° C., the drying time tends to be longer. Although the above temperature range is relatively wide, in order to increase the absolute value of the value represented by (n _x + n _y ) / 2− _nz , it is desirable to perform at a low temperature close to the lower limit (painting). The formation of the internal structure of the film proceeds more). However, since the drying time becomes very long at such a low temperature, the range in which a desired value represented by ( _nx + _ny ) / 2- _nz can be obtained in consideration of the boiling point of the solvent. It is necessary to select the temperature at. Although such constant temperature drying can be used, in order to dry effectively, it is preferable to raise the temperature in multiple stages, and from the economical viewpoint, primary drying and secondary drying are particularly preferable.

When performing two-stage drying, the primary drying preferably has a temperature range of a lower limit of 0 ° C and an upper limit of 40 ° C, more preferably a lower limit of 5 ° C and an upper limit of 35 ° C, and even more preferably a lower limit of 10 ° C and an upper limit of 30 ° C. The drying time is preferably 3 minutes or more. The primary drying is effective for the foundation formation of the internal structure of the coating film for increasing the absolute value of the value represented by (n _x + _ny ) / 2− _nz . When the primary drying temperature is lower than 0 ° C., the drying time required for the basic formation of the inner structure of the coating film tends to be longer. When the primary drying temperature is higher than 40 ° C., it is expressed by (n _x + _ny ) / 2− _nz. There is a tendency that it becomes difficult to form the foundation of the internal structure of the coating film necessary for increasing the absolute value of the value to be determined.

In secondary drying, a temperature range of a lower limit of 80 ° C. and an upper limit of 300 ° C. is preferred, a lower limit of 90 ° C. and an upper limit of 280 ° C. are more preferred, and a lower limit of 100 ° C. and an upper limit of 260 ° C. are more preferred. In addition to completely removing the solvent, the secondary drying has developed the foundation of the internal structure of the coating film formed by the primary drying, and actually has a value expressed by (n _x + _ny ) / 2− _nz. This is effective for increasing the absolute value. If the secondary drying temperature is lower than 80 ° C., the establishment of the internal structure of the coating film tends to be insufficient, and if it is higher than 300 ° C., the coating film or the peelable substrate tends to be thermally deteriorated.

  Furthermore, the present invention provides a method for forming a film by applying a coating liquid to a peelable substrate to form a coated substrate, exposing the coating film to the vapor of component (B), and further drying the coating film. You can also.

  Annealing is preferably performed in order to improve the leveling property of the coating film and to relieve stress. For example, it is effective for reducing in-plane retardation and reducing in-plane retardation. Annealing is preferably carried out by leaving the coating film of the coating substrate in the steam of the component (B) horizontally. The temperature at the time of annealing can be variously set, but the lower limit is preferably −30 ° C. and the upper limit [(B) component boiling point (° C.)], and the lower limit is −15 ° C. and the upper limit [(B) component boiling point (° C.) −5 ° C] is more preferable, and the lower limit is 0 ° C, and the upper limit [the boiling point (° C) of the component (B) -10 ° C] is more preferable. If the temperature during annealing is lower than −30 ° C., the annealing time tends to be longer, and if the temperature during annealing is higher than the boiling point (° C.) of the component (B), the coating film tends to flow out from the peelable substrate. Tend to be. The pressure at the time of annealing can be set variously and can be performed under atmospheric pressure, pressurization, or reduced pressure, but atmospheric pressure is preferable in terms of workability.

  Next, the peelable substrate will be described. The peelable substrate is not particularly limited as long as it has the peelability of the film of the present invention and does not impair the physical properties of the substrate during film formation. Specific examples of compounds that form a release substrate include polycarbonate polymers; polyacrylic esters such as polymethyl acrylate and polymethyl methacrylate; adipic acid, phthalic acid, isophthalic acid, terephthalic acid, 1, Condensates of dibasic acids such as 4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and glycols such as ethylene glycol, diethylene glycol, propylene glycol, tetramethylene glycol, and neopentyl glycol Polyester polymers obtained by ring-opening polymerization of lactones; Styrene polymers such as polystyrene and poly (α-methylstyrene); Copolymers of acrylates and styrene; Polyethylene, polypropylene, norbornene resins, poly Isoprene Polyolefin polymers such as hydrogenated additives and polybutadienes; polyamides such as nylon 6 and nylon 66; polyimides; polyamideimides; polyetherimides; polyvinyl alcohol; polyvinyl chloride; Polyether ether ketone, polyphenylene sulfide, polyphenylene oxide, polyarylate, polyacetal, epoxy resin, phenol resin, silicone resin, metal such as iron, aluminum, and copper, glass, and the like.

  These materials are formed into a sheet shape by, for example, a solution casting method, a melt casting method, an extrusion method, a calendar method, rolling, melt molding, and the like, and are stretched by a non-stretching method, a uniaxial stretching method, a biaxial stretching method, or the like. It can be used as a peelable substrate. Among these compounds, the molded article has a low or relatively low heat shrinkage rate when used at high temperatures and good stability. Therefore, polyethylene terephthalate (condensate of terephthalic acid and ethylene glycol), polyethylene-2,6- Naphthalenedicarboxylate (condensate of 2,6-naphthalenedicarboxylic acid and ethylene glycol), polyimide, polyamideimide, polyetherimide, polysulfone, polyethersulfone, polyetherketone; polyetheretherketone; polyphenylenesulfide; polyarylate; Epoxy resin; phenol resin; metal such as iron, aluminum and copper, glass and the like are preferable.

  In addition, after preparation of the peelable substrate, fluorine surfactant, silicone surfactant, alkyl quaternary ammonium salt, phosphate ester, liquid paraffin, wax, higher fatty acid and higher fatty acid metal salt, higher fatty acid ester, higher fatty acid By applying an external release agent such as alcohol, bisamides, polysiloxanes, aliphatic amine ethylene oxide adducts or the like on one or both sides, a peelable substrate with improved film peelability can be obtained. Furthermore, after the external release agent is added as an internal release agent to the peelable substrate preparation compound, the above-described molding can be performed to provide a peelable substrate with improved film peelability.

  As described above, in the sheet of the present invention, since the substrate has peelability, the adhesive layer is provided on the film surface and bonded to the optical device constituent member, and then the peelable substrate is easily peeled to transfer the film. Alternatively, after the adhesive layer is provided on the optical device constituent member and the film surfaces are bonded together, the peelable substrate is peeled off and the film can be transferred onto the optical device constituent member. Since transfer is performed using a sheet on which a film has already been formed and the optical device constituent member is not affected by a solvent, heating, or the like, the sheet can be preferably used.

  In addition, it is preferable to use an adhesive sheet in which an adhesive layer is provided in advance on the film surface of the sheet, because the transfer operation becomes easier. Examples of the adhesive that can be used at this time include a rubber-based pressure-sensitive adhesive, an acrylic-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a vinyl alkyl ether-based pressure-sensitive adhesive, Polyvinyl alcohol pressure sensitive adhesive, polyvinyl pyrrolidone pressure sensitive adhesive, polyacrylamide pressure sensitive adhesive, cellulose pressure sensitive adhesive, UV curable adhesive, emulsion type adhesive, one-part curable adhesive, two Examples thereof include liquid curable adhesives.

  Next, resins that can be added for the purpose of modifying the characteristics of the membrane containing the cellulose N-substituted carbamate of the present invention will be described. The resins that can be added include polycarbonate resin, acrylic resin, polyester resin, polystyrene resin, polyolefin resin, polyamide resin, polyimide resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyethersulfone resin, polyarylate resin, epoxy. Resins, silicone resins, phenol resins, urethane resins and the like are exemplified, but these can be added within a range that does not impair the object and effect of the present invention.

  Next, additives that can be added for the purpose of modifying the properties of the film and coating solution of the present invention will be described. Additives include antioxidants (eg, hindered phenols such as IRGANOX 1010, IRGANOX 1135, IRGANOX 1330, etc. manufactured by Ciba Specialty Chemicals), processing stabilizers (eg, HP-136, IRGANOX manufactured by Ciba Specialty Chemicals). E201, IRGAFOS 168, etc.), light stabilizers (eg, hindered amines such as Sanol LS-765 and Sanol LS-770 manufactured by Sankyo Lifetech), ultraviolet absorbers (eg, TINUVIN P, TINUVIN 213 manufactured by Ciba Specialty Chemicals) Benzotriazoles such as TINUVIN 326), adhesion improvers (eg, silane compounds such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane) Coupling agent), silanol condensation catalyst (for example, aluminum tris (ethyl acetoacetate) manufactured by Kawaken Fine Chemicals, aluminum chelate M, etc.), plasticizer (for example, dimethyl adipate, diethyl adipate, dipropyl adipate, adipine) Dibutyl acid, bis (2-ethylhexyl) adipate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dipentyl phthalate, dihexyl phthalate, diheptyl phthalate, di-n-octyl phthalate, bis phthalate (Esters such as 2-ethylhexyl)), surfactants (for example, fluorine compounds such as Fluorad FC-430 and Fluorad FC-4430 manufactured by Sumitomo 3M), antistatic agents (for example, Ciba Specialty Chemi) Kalz IRGASTAT P18, IRGASTAT P22, etc.) and the like, and these can be added within a range that does not impair the object and effect of the present invention.

  Resins and additives added for the purpose of modifying the properties of the film and / or coating solution are, for example, mixing the above-mentioned components in the coating solution at a temperature not lower than the melting point and not higher than the boiling point of the solvent in the coating solution. It is obtained by standing still or stirring and mixing.

  Next, the translucent substrate to which the film of the present invention is transferred will be described. Various substrates can be used as long as they are transparent. Examples of specific compounds that form the substrate include polycarbonate polymers; polyacrylic acid esters such as polymethyl acrylate and polymethyl methacrylate; adipic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4 -Condensates or lactones of dibasic acids such as naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and glycols such as ethylene glycol, diethylene glycol, propylene glycol, tetramethylene glycol, and neopentyl glycol Polymers obtained by ring-opening polymerization of polymers; styrene polymers such as polystyrene and poly (α-methylstyrene); copolymers of acrylic acid esters and styrene; polyethylene, polypropylene, norbornene resins, cycloolefins Poly -Polyolefin polymers such as hydrogenated polyisoprene and hydrogenated polybutadiene; Cellulose resins such as cellulose acetate having a substitution degree of 2 to 3 by acetyl groups; Polyamides such as nylon 6 and nylon 66; Polyimides; Polyvinylimide; Polyvinyl alcohol; Polyvinyl chloride; Polysulfone; Polyethersulfone; Polyarylate; Epoxy resin; Silicone resin; Compounds described in International Publication No. 01/37007 pamphlet.

  In addition, these materials are formed by, for example, a solution casting method, a melt casting method, an extrusion method, a calendering method, and the like, and are contracted by using a non-stretching method, a uniaxial stretching method, a biaxial stretching method, or a shrinkable film. It can be stretched by a method or the like and used as a translucent substrate. On the other hand, a glass plate, a color filter, a liquid crystal cell, or the like can be used as the substrate. These translucent substrates should be at least one easy-adhesion treatment selected from corona treatment, plasma treatment, frame treatment, primer coating treatment, saponification treatment, etc., to be a translucent substrate with improved adhesion. You can also. The translucent substrate used in the present invention may be formed by transferring a film (either on one side or on both sides) to form a film on the substrate and then incorporating this laminated state into various optical devices as it is. good. According to this method, an element having a film for optical compensation can be formed more easily. For example, a polarizing plate or the like having an optical compensation function, in which the translucent substrate itself is attached to a polarizer as a protective material, can be used.

  Next, a film having controlled birefringence (in the present invention, a film is formed on a light-transmitting substrate, and this laminated structure is used as an element having a film for optical compensation or a part thereof as it is. In particular, when the birefringence of the translucent substrate is controlled, the substrate will be described in this way). The “film having controlled birefringence” can be obtained by newly imparting birefringence by, for example, uniaxial stretching, biaxial stretching, or shrinking using a shrinkable film. As a film having controlled birefringence, various films can be used as long as the birefringence is controlled to a desired birefringence, regardless of whether the film is positive birefringence, negative birefringence, or zero birefringence. In particular, from the viewpoint of viewing angle compensation, a film made of a material having positive birefringence can be preferably used. Specific examples of materials having positive birefringence include polycarbonate, polyethylene terephthalate, polypropylene, norbornene resin, cycloolefin polymer, cellulose resin, polyimide, polyvinyl alcohol, polysulfone, polyethersulfone, polyarylate, and the like. It is done. Incidentally, when a film having a positive birefringence is subjected to general longitudinal uniaxial stretching or the like to form a film, it has optically positive uniaxiality and its optical axis is parallel to the film surface. When an A plate is used together with the film of the present invention, an optical compensation function such as reduction of light leakage in the dark state of the liquid crystal display device is manifested and useful.

Preferred in-plane retardation of a film having controlled birefringence ((n _{xf −ny f} ) × d _f , where n _{xf is the} largest in the in-plane refractive index of the film, and x is the smallest n _yf , when the film thickness is d _f (nm)), when measured with 590 nm light, the in-plane retardation is preferably controlled such that the lower limit is 0 nm and the upper limit is 600 nm, and the lower limit is 0 nm and the upper limit is It is more preferable that the thickness is controlled to be 500 nm, and it is more preferable that the lower limit is 0 nm and the upper limit is 400 nm. When the in-plane retardation is larger than 600 nm, the retardation compensation effect of the laminate obtained by forming the film of the present invention on the film surface tends to be lowered.

On the other hand, the film of the present invention, largest of the n _x of the in-plane refractive _index, minimum one of the n _y, the refractive index in the thickness direction n _z, when the film thickness is d, [(n _x + n _y ) / 2−n _z ] × d <0. Further, when the membrane thickness and d (nm), the in-plane retardation _{is, (n} x -n _y) is represented by × d, the thickness retardation, _{[(n x + n y) /} 2-n z ] The lower limit of 0 nm and the upper limit of 300 nm is preferable, the lower limit of 0 nm and the upper limit of 200 nm are more preferable, and the lower limit of 0 nm and the upper limit of 100 nm are more preferable. If the in-plane retardation is larger than 300 nm, it tends to be difficult to compensate for the retardation due to birefringence in a liquid crystal cell or the like. In addition, the thickness retardation is preferably lower limit −1000 nm and upper limit −1 nm, more preferably lower limit −800 nm and upper limit −10 nm, and further preferably lower limit −600 nm and upper limit −20 nm in the measurement with 590 nm light. If the thickness phase difference is smaller than −1000 nm, it tends to be difficult to compensate for the phase difference due to birefringence in a liquid crystal cell or the like.

  Next, the laminated body of this invention is demonstrated. The laminate of the present invention is formed by adhering the film of the present invention to at least one surface of the translucent substrate via an adhesive layer. As described above, the translucent substrate is positively birefringent. A film having controlled birefringence formed from a material having a property is preferable.

  Next, the polarizing plate of the present invention will be described. As a polarizing plate, for example, a protective material is bonded to both surfaces of a polarizer using an adhesive such as a polyester adhesive, a polyacrylic adhesive, an epoxy adhesive, a cyanoacrylic adhesive, or a polyurethane adhesive. And the like. Examples of polarizers include polarizers made by adsorbing and orienting iodine and / or dichroic dyes on hydrophilic polymer films, and polyenes formed by dehydration treatment of polyvinyl alcohol-based films. Examples include polarizers and polyvinyl chloride films prepared by dehydrochlorination treatment to form polyene and orientation. Examples of the hydrophilic polymer film used for the polarizer include a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, a saponified film of an ethylene-vinyl acetate copolymer, and the like. As the protective material, those exemplified above as the translucent substrate can be used. In particular, the above-described laminate can also be used. In this case, an optical compensation function can be added to the polarizing plate in addition to the polarizing plate function. When the laminate of the present invention is used as a protective material, it can be used on both sides of a polarizer, the laminate of the present invention is used on one side, and the light-transmitting substrate or the like is simply used on the opposite side. You can also. In addition, the film of the present invention can be separately provided by transfer after preparing these polarizing plates.

  Next, the liquid crystal display device of the present invention will be described. Examples of the liquid crystal display device include a display device configured in the order of light source / light guide plate / light diffusion film / lens film / brightness enhancement film / polarizing plate / liquid crystal cell / polarizing plate. The liquid crystal of the present invention is mounted by mounting the laminate of the present invention on the side and / or the outgoing light side and / or mounting the polarizing plate of the present invention on the polarizing plate on the incident light side and / or outgoing light side of the liquid crystal cell. It can be a display device. Examples of the liquid crystal cell method include a VA (Vertical Alignment) method, an IPS (In-Plane Switching) method, an OCB (Optically Compensated Birefringence) method, and the like.

  Note that the film of the present invention, an element having a film for optical compensation manufactured using the film, and a laminate are used for expanding the viewing angle of a liquid crystal display device using a liquid crystal cell of VA mode, IPS mode, OCB mode, etc. Can be used for In order to sufficiently exhibit the performance of the optical characteristics of the film in the present invention, the IPS system is particularly preferable. The film of the present invention, the element having the film for optical compensation manufactured using the film, and the laminate are liquid crystal display device production parts such as a video, a camera, a mobile phone, a personal computer, a TV, a monitor, and an instrument panel of an automobile. Etc. can be suitably used.

  Examples are shown below to describe the present invention in more detail, but the present invention is not limited to these examples.

(1) The three-dimensional refractive indexes _{[(n x, n y, n} z) or _{(n xf, n yf, n} zf) ] using the calculated Oji Scientific Instruments Ltd. automatic birefringence meter KOBRA-WR of under 25 ° C. Was measured with 590 nm light, and the three-dimensional refractive index was calculated. From the results obtained, it was determined by an in-plane retardation _(n x -n _y) × d or _{(n xf -n yf) × d} f. It was also determined by the thickness retardation _{[(n x + n y) /} 2-n z ] × d or _{[(n xf + n yf) /} 2-n zf ] × _{d f.} However, when the phase difference is measured with the slow axis as the tilt center axis, the in-plane phase difference is 10 nm or less, and when the phase difference increases with the tilt angle, the sign of the phase difference is determined. The following method was used in combination. After overlaying the polycarbonate λ / 4 plate on the laminate and attaching it to the automatic birefringence meter KOBRA-WR so that the orientation angle of the λ / 4 plate is 0 ± 1 degree, the slow axis is the center of inclination. The phase difference was measured with 590 nm light at 25 ° C. with the axis. If the measurement result is higher than the phase difference of the λ / 4 plate alone, it is considered that the phase difference of the laminated body also increases in the positive direction as the tilt angle increases, and is lower than the phase difference of the λ / 4 plate alone. In this case, it is assumed that the phase difference of the single layer of the laminate decreases in the negative direction as the tilt angle increases, and a positive / negative sign is given to the phase difference of the single layer of the laminate previously measured, and the three-dimensional refractive index is set. Calculated. From the results obtained, it was determined by an in-plane retardation _(n x -n _y) × d or _{(n xf -n yf) × d} f. It was also determined by the thickness retardation _{[(n x + n y) /} 2-n z ] × d or _{[(n xf + n yf) /} 2-n zf ] × _{d f.}

(2) Haze measurement Measured according to JIS K 7136.

(Synthesis Example 1) Synthesis of cellulose N-phenyl carbamate (1) Cellulose (manufactured by Asahi Kasei Chemicals) was vacuum-dried at 60 ° C. for 7 hours in a 500 ml four-necked flask equipped with a cooling tube, a nitrogen introduction tube, a stirrer, and a thermometer. Avicel TG-F20) (3.0 g) was added, 300 ml of pyridine was added to form a suspension, and then 23.1 g of phenyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. Nitrogen was introduced, and the temperature was raised to 110 ° C. with stirring, followed by reaction for 7 hours. Then, after cooling to 25 degreeC, the reaction liquid was dripped in 1200 ml of ethanol, and the precipitation was produced | generated. After separation by filtration, the obtained polymer was dissolved by adding 90 ml of acetone, and then dropped into 1200 ml of pure water to cause precipitation. After separation by filtration, washing with water and vacuum drying at 60 ° C. for 8 hours, the polymer was put into a Soxhlet extractor. After performing Soxhlet extraction with methanol 20 times and vacuum-drying at 25 ° C. for 8 hours, 5.7 g of cellulose N-phenylcarbamate (1) was obtained (hereinafter sometimes referred to as synthetic product (1)). .) DS of the synthesized product (1) was 3 as a result of proton NMR analysis. In addition, DS was determined by comparing the chemical shift (3.4 to 5.5 ppm) area of proton derived from the cellulose skeleton with the chemical shift (6.7 to 7.8 ppm) area of the proton of the phenyl group.

(Example 1)
To 0.6 g of the synthesized product (1), 1.96 g of n-pentyl acetate, 1.96 g of n-hexyl acetate, 0.49 g of ethylene glycol monobutyl ether and 0.06 g of dimethyl phthalate were added and dissolved at 25 ° C. Next, this coating solution was coated on a 50 μm-thick polyethylene terephthalate film using a bar coater to obtain a coated substrate. Thereafter, the coated substrate was dried while being blown in air at 25 ° C. for 15 minutes, and further dried in air at 160 ° C. for 5 minutes to produce a sheet on which an optical compensation film was formed. Subsequently, an acrylic pressure-sensitive adhesive layer was formed on the film surface to obtain an adhesive sheet. The adhesive sheet is bonded to a glass substrate (average refractive index: 1.52, in-plane retardation: 0 nm, thickness retardation: 1 nm) by pressure bonding through a pressure-sensitive adhesive layer, and then the polyethylene terephthalate film is peeled off. By doing so, the laminated body was able to be produced easily. The thickness (d (nm)) of the optical compensation film of the laminate is measured by measuring the thickness of the entire sheet on which the optical compensation film is formed, and subtracting the thickness of the polyethylene terephthalate film. The obtained value was used as it was. The film thickness was 12000 nm. As a result of measuring the physical properties of the obtained laminate, the in-plane retardation was 1 nm, the thickness retardation was -89 nm, and the haze was 1.0%.

(Example 2)
Example except that a cellulose acetate film (41 μm thickness, in-plane retardation: 1 nm, thickness retardation: 30 nm, glass transition temperature: 153 ° C.) having a degree of substitution with acetyl groups of 2.5 was used instead of the glass substrate The same operation as 1 was performed. As a result of measuring the physical properties of the obtained laminate, the in-plane retardation was 2 nm, the thickness retardation was -55 nm, and the haze was 0.9%.

(Example 3)
The same operation as in Example 1 was performed except that a 87 μm-thick cycloolefin polymer uniaxially stretched film (in-plane retardation: 215 nm, thickness retardation: 100 nm, glass transition temperature: 138 ° C.) was used instead of the glass substrate. went. As a result of measuring the physical properties of the obtained laminate, the in-plane retardation was 211 nm, the thickness retardation was 20 nm, and the haze was 1.1%.

(Comparative Example 1)
A cellulose acetate film (41 μm thickness, in-plane retardation: 1 nm, thickness retardation: 30 nm, glass transition temperature: 153) having a substitution degree of 2.5 with an acetyl group was applied to the coating solution prepared in Example 1 using a bar coater. C.) to obtain a coated substrate. Thereafter, the coated substrate was dried while being blown in the air at 25 ° C. for 15 minutes, and further dried in the air at 160 ° C. for 5 minutes. As a result, the cellulose acetate film contracted, and the film for optical compensation was reduced. Only a laminate with varying thickness was obtained.

(Comparative Example 2)
The coating liquid prepared in Example 1 was applied to a uniaxially stretched film (in-plane retardation: 215 nm, thickness retardation: 100 nm, glass transition temperature: 138 ° C.) of 87 μm thickness using a bar coater. A coated substrate was obtained. Thereafter, the coated substrate was dried while being blown in air at 25 ° C. for 15 minutes, and further dried in air at 160 ° C. for 5 minutes. As a result, the uniaxially stretched film of the cycloolefin polymer contracted and wrinkled. Thus, only a laminate was obtained.

Example 4
A polyvinyl alcohol film was impregnated with iodine and stretched to prepare a polarizer. A cellulose acetate film (80 μm thick) having a degree of substitution with an acetyl group of 2.5 was bonded to one side of the polarizer using a polyacrylic adhesive. Further, the laminate produced in Example 2 was bonded to the opposite surface of the polarizer using a polyacrylic adhesive so that the coating film surface was on the outside, and a polarizing plate having an optical compensation layer was produced.

(Example 5)
A liquid crystal display device equipped with an IPS liquid crystal cell was prepared, and a display device was produced in which the laminate produced in Example 2 was superimposed on the outgoing light side of the liquid crystal cell. As a result of observing the display screen, a good image was obtained without changing the color display when viewed from the front or from an oblique direction.

(Example 6)
Prepare a liquid crystal display device equipped with an IPS liquid crystal cell, remove the polarizing plate on the outgoing light side, and replace the polarizing plate produced in Example 4 with the coating film surface facing the outgoing light side of the liquid crystal cell. A display device bonded to a liquid crystal cell was manufactured. As a result of observing the display screen, a good image was obtained without changing the color display when viewed from the front or from an oblique direction.

(Comparative Example 3)
The same operation as in Example 5 was performed except that the laminate produced in Example 2 was not used. As a result, when viewed from an oblique direction, the color display was different from that viewed from the front due to the birefringence of the liquid crystal display device constituent members.

(Comparative Example 4)
The same operation as in Example 6 was performed except that the polarizing plate produced in Example 4 was not used and the polarizing plate on the outgoing light side was used as it was. As a result, when viewed from an oblique direction, the color display was different from that viewed from the front due to the birefringence of the liquid crystal display device constituent members.

Claims (10)

  A sheet having a film containing cellulose N-substituted carbamate on a peelable substrate. Largest of the n _x of the in-plane refractive index of claim 1 wherein the _film, the smallest ones and n _y, the refractive index in the thickness direction n _z, the thickness is taken as d, the following formula 1 The sheet according to claim 1, wherein:
[(N _x + n _y ) / 2−n _z ] × d <0 (Formula 1) In the cellulose N-substituted carbamate, at least one hydroxyl group of cellulose is N-substituted carbamate, and at least one hydrogen atom bonded to the nitrogen atom of the carbamate group is represented by the following general formulas (1) to (3). (The substituent bonded to N), and the substituents bonded to N of the plurality of N-substituted carbamate groups are the same or different and are represented by the following general formulas (1) to (3). The sheet according to claim 1, wherein the sheet is a group selected from the group consisting of:

(Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or 1 to 20 carbon atoms. Halogenated alkyl groups, C6-C20 aryl groups, C6-C20 aryloxy groups, C7-C20 aralkyl groups, C7-C20 aralkyloxy groups, C1-C21 Represents an acyloxy group, a halogen atom, or a nitro group.)

(Wherein R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Represents a halogenated alkyl group having 1 to 20 carbon atoms, an acyloxy group having 1 to 21 carbon atoms, a halogen atom, or a nitro group.)

(In the formula, R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Represents a halogenated alkyl group having 1 to 20 carbon atoms, an acyloxy group having 1 to 21 carbon atoms, a halogen atom, or a nitro group.)   The adhesive sheet provided with the adhesive bond layer on the film | membrane surface containing the cellulose N-substituted carbamate of the sheet | seat of Claim 1 thru | or 3.   A method for producing a laminate, comprising: bonding an adhesive sheet according to claim 4 to at least one surface of a light-transmitting substrate via an adhesive layer, and then peeling the peelable substrate.   The method for producing a laminate according to claim 5, wherein the translucent substrate is a film having controlled birefringence.   The method for producing a laminate according to claim 6, wherein the film having controlled birefringence is a film made of a material having positive birefringence.   A laminate manufactured using the method according to claim 5.   A polarizing plate comprising the laminate according to claim 8 mounted on at least one surface of a polarizer as a protective material for the polarizer.   A liquid crystal display device comprising at least one structure selected from the laminate according to claim 8 and the polarizing plate according to claim 9.