JP2009204834A - Optical film, optical functional film, polarizing plate and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film with superior scratch resistance and which is improved in tearing strength and folding strength, a functional film using an optical film such as a substrate, and to provide a polarizing plate and an image display device provided with the functional film. <P>SOLUTION: The optical film is formed of a polymer mainly composed of cellulose ester and containing polyrotaxane. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical film containing a polyrotaxane. In particular, the present invention relates to an optical film mainly composed of cellulose acylate, a functional film based thereon, and a polarizing plate and an image display device using such a functional film.

Cellulose acylate films are widely used as optical films by taking advantage of excellent properties such as transparency, mechanical strength, and optical isotropy.
For example, in a liquid crystal display device, a cellulose acylate film is used as a base material for a retardation film or an antireflection film, and as a protective film for a polarizing plate.
By the way, such an optical film is required to have high productivity as the price of a liquid crystal display device on which the optical film is mounted is reduced. In order to increase productivity, it is necessary to perform anti-reflection processing (lamination of hard coat layer and anti-reflection layer) and polarizing plate processing at higher speed, and cellulose acylate film has higher handling suitability at higher speed. It has been requested.

  The cellulose acylate film has low tear strength and folding strength as it is, and has a drawback that it becomes very brittle and easily tears particularly under low humidity conditions. Therefore, in order to improve these, a solution casting film forming method of cellulose acylate is used, and a plasticizer (for example, phosphate ester, phthalate ester, etc.) is appropriately selected for the cellulose acylate solution and used alone. Alternatively, the tear strength and folding strength are improved by using a mixed dope composition. However, even these films do not have sufficient tear strength and bending strength, and cause cutting during high-speed handling. Therefore, higher tear strength and bending strength have been demanded.

In recent years, a new type of gel that has not been classified as either a physical gel or a chemical gel using a novel method, that is, a “ringing gel or topological gel” has been proposed, and polyrotaxane is used for such a ringing gel. It has been. A polyrotaxane is a conceptual compound having a structure in which a cyclic compound and a linear polymer that passes through the cyclic compound are plurally capped, and both ends of the linear polymer are capped.
Patent Document 1 discloses a polyrotaxane using α-cyclodextrin as a cyclic compound and polyethylene glycol as a linear polymer.

Patent Document 2 discloses a crosslinked polyrotaxane that can be applied to a oscillating gel by crosslinking a plurality of the polyrotaxanes.
This cross-linked polyrotaxane has viscoelasticity because the cyclic molecule that is skewered through the linear molecule can move along the linear shape (pulley effect). Even if tension is applied, this pulley effect Therefore, unlike the conventional crosslinked polymer, it has an excellent property that cracks and scratches are hardly generated.

  Such polyrotaxanes or crosslinked polyrotaxanes have been studied for application in various fields, but application studies of such polyrotaxanes for optical films, particularly polarizing plate protective films for liquid crystal display devices, have not been promoted.

Further, as an application to a plastic plate, Patent Document 3 discloses a colored plastic plate for automobiles containing polyrotaxane.
Japanese Patent No. 2810264 Japanese Patent No. 3475252 JP 2007-099989 A

  An object of the present invention is to provide a cellulose ester film which has excellent scratch resistance and improved tear strength and folding strength while ensuring the characteristics of optical properties. Furthermore, it is providing the functional film which used such an optical film as a base material, and providing the polarizing plate and image display apparatus which comprised this functional film.

  The present inventor has excellent scratch resistance and improved tear strength and folding strength while maintaining flexibility, high transparency, low haze, and control of optical anisotropy by containing polyrotaxane. It was found that an optical film mainly composed of cellulose ester film, particularly cellulose acylate was obtained.

That is, the present inventor has achieved the above object by the following configurations.
(1) An optical film comprising a polymer containing a cellulose ester as a main component and a polyrotaxane.
(2) The optical film as described in (1), wherein the content of the polyrotaxane is 0.1 to 30 parts by mass with respect to the polymer.
(3) The optical film as described in (1) or (2), wherein the cyclic molecule of the polyrotaxane is cyclodextrin.
(4) When the cyclic molecule of the polyrotaxane is a cyclodextrin in which a hydroxyl group is modified with a hydrophobic modifying group, and the degree of modification with the hydrophobic modifying group is 1, the maximum number of hydroxyl groups of the cyclodextrin that can be modified is It is 0.02 or more, The optical film as described in (3) characterized by the above-mentioned.
(5) The optical film as described in any one of (1) to (4), wherein the polyrotaxane is a crosslinked polyrotaxane.
(6) A part or all of the OH group of cellulose is substituted with an acyl group, and the acyl group substitution degree is in the range of 2.0 to 3.0. (1) to (5) The optical film in any one.
(7) The optical film as described in any one of (1) to (6), wherein at least one of the acyl groups is an acyl group having 3 to 20 carbon atoms.
(8) The optical film as described in any one of (1) to (7) above, wherein the polyrotaxane linear molecule has a polyethylene glycol chain.
(9) An optical functional film characterized in that the optical film described in (1) to (8) is used as a base material and a functional layer is further laminated.
(10) The functional layer is any one of a hard coat layer, an antiglare layer, an antireflection layer, a polymer layer, and an optical compensation layer, or a plurality of layers selected from these (9) ) Optical functional film.
(11) A polarizing plate using the optical film according to any one of (1) to (8) as a polarizing plate protective film.
(12) An image display device comprising the optical film according to any one of (1) to (8).

  According to the present invention, while maintaining flexibility, high transparency, low haze, and control of optical anisotropy, an optical film having excellent scratch resistance and improved tear strength and folding strength is produced. be able to.

Hereinafter, a method for producing the optical film of the present invention will be described. However, the present invention is not limited by the following description.
In addition, in this specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” represents the meaning of “numerical value 1 or more and numerical value 2 or less”.
“Resin” has a meaning including a monomer, an oligomer and a prepolymer.
“(Meth) acrylate” means methacrylate and acrylate.

<Polyrotaxane>
The polyrotaxane, which is an essential component in the present invention, will be described.
The polyrotaxane has an opening portion of a cyclic molecule pierced by a linear molecule, and a plurality of cyclic molecules include the linear molecule at both ends (both ends of the linear molecule). A blocking group is arranged so that the cyclic molecule is not liberated.

(Linear molecule)
The linear molecule contained in the compound of the present invention is not particularly limited as long as it is a molecule or substance that is included in a cyclic molecule and can be integrated non-covalently and is linear. . In the present invention, the “linear molecule” refers to a molecule including a polymer and all other substances satisfying the above requirements.
In the present invention, “linear” of “linear molecule” means substantially “linear”. That is, the linear molecule may have a branched chain as long as the cyclic molecule that is a rotor is rotatable or the cyclic molecule is slidable or movable on the linear molecule. Further, the length of the “straight chain” is not particularly limited as long as the cyclic molecule can slide or move on the linear molecule.

  As the linear molecule of the present invention, hydrophilic polymers such as polyvinyl alcohol and polyvinylpyrrolidone, poly (meth) acrylic acid, cellulose resins (carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, etc.), polyacrylamide, polyethylene oxide, polyethylene Glycol, polyvinyl acetal resin, polyvinyl methyl ether, polyamine, polyethyleneimine, casein, gelatin, starch, etc. and / or copolymers thereof; hydrophobic polymers such as polyethylene, polypropylene, and other olefinic monomers Polyolefin resins such as copolymer resins, polyester resins, polyvinyl chloride resins, polystyrenes such as polystyrene and acrylonitrile-styrene copolymer resins Resins, polymethylmethacrylate, (meth) acrylic acid ester copolymers, acrylic resins such as acrylonitrile-methyl acrylate copolymer resins, polycarbonate resins, polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins, etc. And derivatives or modified products thereof.

  Of these, hydrophilic polymers are preferred.

  Among the hydrophilic polymers, polyethylene glycol, polypropylene glycol, a copolymer of polyethylene glycol and polypropylene glycol, polyisoprene, polyisobutylene, polybutadiene, polytetrahydrofuran, polydimethylsiloxane, polyethylene, and polypropylene are preferable. Polyethylene glycol, polyethylene glycol, and a copolymer of polyethylene glycol and polypropylene glycol are more preferable, and polyethylene glycol is particularly preferable.

The linear molecule of the present invention has a molecular weight of 1,000 or more, such as 1,000 to 1,000,000, preferably 5,000 or more, such as 5,000 to 1,000,000 or 5,000 to 5,000. It is good to be 500,000, more preferably 10,000 or more, for example, 10,000 to 1,000,000, 10,000 to 500,000, or 10,000 to 300,000.
The linear molecule of the present invention is preferably a biodegradable molecule from the viewpoint of “environmentally friendly”.

  The linear molecule of the present invention preferably has reactive groups at both ends. By having this reactive group, it can react easily with a blocking group. The reactive group depends on the block group to be used, and examples thereof include a hydroxyl group, an amino group, a carboxyl group, and a thiol group.

(Cyclic molecule)
The cyclic molecule of the present invention can be any cyclic molecule as long as it is a cyclic molecule that can be included in the linear molecule.
In the present invention, “cyclic molecule” refers to various cyclic substances including cyclic molecules. In the present invention, “cyclic molecule” refers to a molecule or substance that is substantially cyclic. That is, “substantially ring-shaped” means that the letter “C” is not completely closed, such as the letter “C”, and one end and the other end of the letter “C” are not joined. It is intended to include those having overlapping spiral structures. Furthermore, a ring for a “bicyclo molecule” to be described later can be defined in the same manner as “substantially cyclic” in “cyclic molecule”. That is, one or both rings of the “bicyclo molecule” may not be completely closed like the letter “C”, and one end and the other end of the letter “C” are connected to each other. It may have a spiral structure that is not overlapped.

  Examples of the cyclic molecule of the present invention include various cyclodextrins (for example, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, dimethylcyclodextrin and glucosylcyclodextrin, derivatives or modified products thereof), crown ethers, and the like. Benzocrowns, dibenzocrowns, and dicyclohexanocrowns, and derivatives or modified products thereof.

The above-mentioned cyclodextrins and crown ethers differ in the size of the opening of the cyclic molecule depending on the type. Therefore, the type of linear molecule to be used, specifically, when the linear molecule to be used is assumed to be cylindrical, the cyclic molecule to be used depends on the diameter of the cross section of the cylinder, the hydrophobicity or hydrophilicity of the linear molecule, etc. Can be selected. When a cyclic molecule having a relatively large opening and a cylindrical linear molecule having a relatively small diameter are used, two or more linear molecules can be included in the opening of the cyclic molecule. .
Among these, cyclodextrins are preferable from the above-mentioned “environmentally friendly” point because they have biodegradability.

It is preferable to use α-cyclodextrin as the cyclic molecule.
When the cyclic molecule is cyclodextrin, the number of cyclic molecules included in the linear molecule (inclusion amount) is preferably 0.05 to 0.60, with the maximum inclusion amount being 1. 10-0.50 is still more preferable and 0.20-0.40 is still more preferable. If it is less than 0.05, the pulley effect may not be exhibited. If it exceeds 0.60, cyclodextrin, which is a cyclic molecule, may be arranged too densely, and the mobility of cyclodextrin may be reduced. Insolubility in the organic solvent may be strengthened, and the solubility of the resulting polyrotaxane in the organic solvent may be reduced.

  The cyclic molecule of the present invention preferably has a reactive group outside the ring. When the cyclic molecules are bonded or cross-linked, the reaction can be easily performed using this reactive group. The reactive group depends on the crosslinking agent used, and examples thereof include a hydroxyl group, an amino group, a carboxyl group, a thiol group, and an aldehyde group. Moreover, it is good to use the group which does not react with a blocking group in the above-mentioned blocking reaction.

(Block base)
As the blocking group of the present invention, any group may be used as long as the cyclic molecule maintains a form in which the cyclic molecule is skewered with a linear molecule. Examples of such a group include a group having “bulkiness” and / or a group having “ionicity”. Here, the “group” means various groups including a molecular group and a polymer group. In addition, the “ionicity” of the group having “ionicity” and the “ionicity” of the cyclic molecule influence each other, for example, by repulsion, the cyclic molecule is skewered by linear molecules. It is possible to retain the form.

  The blocking group of the present invention may be a polymer main chain or a side chain as long as it retains the skewered shape as described above. When the blocking group is the polymer A, the matrix of the present invention is included in the matrix A and the compound of the present invention is included in a part thereof. The form in which A is included may be sufficient. Thus, by combining with the polymer A having various properties, a composite material having a combination of the properties of the compound of the present invention and the properties of the polymer A can be formed.

  Specifically, as a blocking group of the molecular group, dinitrophenyl groups such as 2,4-dinitrophenyl group and 3,5-dinitrophenyl group, cyclodextrins, adamantane groups, trityl groups, fluoresceins and pyrene And derivatives or modified products thereof. More specifically, even when α-cyclodextrin is used as a cyclic molecule and polyethylene glycol is used as a linear molecule, cyclodextrins, 2,4-dinitrophenyl group, 3,5-dinitrophenyl group, etc. And dinitrophenyl groups, adamantane groups, trityl groups, fluoresceins and pyrenes, and derivatives or modified products thereof.

  Next, a modified polyrotaxane that can be preferably used in the present invention will be described. In the present invention, a polyrotaxane in which a plurality of modifications described below are used in combination can be preferably used.

<Cross-linked polyrotaxane>
A crosslinked polyrotaxane refers to a compound in which two or more polyrotaxanes are chemically bonded to each other, and the two cyclic molecules may be the same or different. At this time, the chemical bond may be a simple bond or a bond via various atoms or molecules.
In addition, a molecule in which a cyclic molecule has a bridged ring structure, that is, a “bicyclo molecule” having first and second rings can be used. In this case, for example, a “bicyclo molecule” and a linear molecule can be mixed, and the crosslinked polyrotaxane can be obtained by including the linear molecule in a skewered manner in the first and second rings of the “bicyclo molecule”.
This crosslinked polyrotaxane has viscoelasticity because the cyclic molecules penetrating the linear molecule in a skewered manner can move along the linear shape (pulley effect). The tension can be uniformly dispersed by the effect, and the internal stress can be relaxed.

<Hydrophobic modified polyrotaxane>
When the cyclic molecule of polyrotaxane is a cyclodextrin such as α-cyclodextrin, in the present invention, at least one hydroxyl group of cyclodextrin is substituted with another organic group (hydrophobic group). Since the solubility to the solvent contained in a layer forming composition improves, it is used more preferably.
Specific examples of hydrophobic groups include, for example, alkyl groups, benzyl groups, benzene derivative-containing groups, acyl groups, silyl groups, trityl groups, nitrate ester groups, tosyl groups, alkyl-substituted ethylenically unsaturated groups as photocuring sites, and thermosetting sites. Examples thereof include, but are not limited to, an alkyl-substituted epoxy group. Moreover, in said hydrophobic modification polyrotaxane, you may have 1 type of the above-mentioned hydrophobic group individually or in combination of 2 or more types.

The degree of modification by the hydrophobic modifying group is preferably 0.02 or more, more preferably 0.04 or more, and more preferably 0.06 or more, assuming that the maximum number of cyclodextrin hydroxyl groups that can be modified is 1. More preferably.
If it is less than 0.02, the solubility in an organic solvent will not be sufficient, and insoluble bumps (protrusions derived from adhesion of foreign matter, etc.) may be generated.
Here, the maximum number that the hydroxyl groups of cyclodextrin can be modified is, in other words, the total number of hydroxyl groups that cyclodextrin had before modification. In other words, the degree of modification is the ratio of the number of modified hydroxyl groups to the total number of hydroxyl groups.
Although at least one hydrophobic modifying group may be used, in that case, it is preferable to have one hydrophobic modifying group for one cyclodextrin ring.
Further, by introducing a hydrophobic modifying group having a functional group, the reactivity with other polymers can be improved.

The blending amount of the polyrotaxane is preferably 0.1 to 30 parts by weight, more preferably 3 to 25 parts by weight, and still more preferably 3 to 20 parts by weight with respect to 100 parts by weight of the polymer. If the amount is less than 0.1 part by weight, the effect of improving the scratch resistance of the polyrotaxane cannot be obtained, and if it exceeds 30% by weight, the problem of an increase in haze due to aggregation of the polyrotaxanes becomes obvious.
In the present invention, the polyrotaxane used is preferably a hydrophobized modified polyrotaxane.

The optical film of the present invention contains cellulose ester as a main component. The phrase “containing a cellulose ester as a main component” means that the polymer having the highest mass fraction contained in the optical film is a cellulose ester.
Examples of the polymer material that can be used in the optical film of the present invention include polyamide, polycarbonate, polyester (for example, polyethylene terephthalate, polyethylene naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, polyethylene-1,2). -Diphenoxyethane-4,4'-dicarboxylate, polybutylene terephthalate, etc.), polystyrene (eg, syndiotactic polystyrene), polyolefin (eg, polypropylene, polyethylene, polymethylpentene, etc.), polysulfone, polyethersulfone, poly Arylate, polyetherimide, polymethyl methacrylate and polyether ketone are included. Cellulose ester, polycarbonate, polyethylene terephthalate and polyethylene naphthalate are preferred.
In particular, when the optical film of the present invention is used in a liquid crystal display device, a cellulose acylate film is preferable because it is easy to process a polarizing plate and does not generate negative uniform optical anisotropy.

  As the cellulose ester of the present invention, a known cellulose ester can be used. For example, preferable cellulose ester is an ester of a fatty acid having 20 or less carbon atoms, more preferably an ester of a fatty acid having 6 or less carbon atoms. Specific examples include organic acid esters such as cellulose acetate, cellulose propionate, and cellulose butyrate. The cellulose ester is, for example, a mixed organic acid ester (for example, cellulose acetate propionate, cellulose acetate butyrate in which a part of the hydroxyl group of cellulose is substituted with an acetyl group and another part is substituted with a propionyl group. Rate). The cellulose ester is produced by any appropriate method (for example, the method described in JP-A-2001-188128).

  When the cellulose ester of the present invention contains an acetyl group, the degree of acetyl substitution is preferably 2.0 to 2.98, and more preferably 2.2 to 2.96. When the said cellulose ester contains a propionyl group, the propionyl substitution degree becomes like this. Preferably it is 0.5-3.0, More preferably, it is 0.5-2.5. Further, when the cellulose ester is a mixed organic acid ester in which a part of the hydroxyl group of cellulose is substituted with an acetyl group and another part is substituted with a propionyl group, the sum of the degree of acetyl substitution and the degree of propionyl substitution is , Preferably it is 2.0-3.0, More preferably, it is 2.2-3.0. In this case, the degree of acetyl substitution is preferably 1.0 to 2.8, and the degree of propionyl substitution is preferably 1.0 to 2.0.

  In the present specification, the degree of acetyl substitution (or propionyl substitution) refers to the number of hydroxyl groups attached to carbons at 2, 3, and 6 positions in the cellulose skeleton with acetyl groups (or propionyl groups). The acetyl group (or propionyl group) may be biased to any of the carbons at the 2, 3, 6 positions in the cellulose skeleton, or may exist on average. The said acetyl substitution degree can be calculated | required by ASTM-D817-91 (test methods, such as a cellulose acetate). Moreover, the said propionyl substitution degree can be calculated | required by ASTM-D817-96 (test methods, such as a cellulose acetate).

A specific example of a particularly preferable cellulose ester is cellulose acetate satisfying the following formula (I) when the substitution degree of the acetyl group is X.
2.6 ≦ X ≦ 3.0 (I)
Another specific example of the cellulose ester has an acyl group having 2 to 4 carbon atoms as a substituent, the substitution degree of acetyl group is X, and the substitution degree of propionyl group or butyryl group is Y, It is a cellulose ester including a cellulose ester that simultaneously satisfies the formulas (II) and (III).
2.6 ≦ X + Y ≦ 3.0 (II)
0 ≦ X ≦ 2.5 (III)
Among them, cellulose acetate propionate is preferable, and it is particularly preferable that 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9. The portion not substituted with an acyl group usually exists as a hydroxyl group.

The cellulose ester preferably has a weight average molecular weight (Mw) measured by a gel permeation chromatograph (GPC) method using a tetrahydrofuran solvent, preferably 30,000 to 500,000, more preferably 50,000 to 400,000. Most preferably, it is 80,000-300,000. When the weight average molecular weight is in the above range, a material having excellent mechanical strength, good solubility, moldability, and casting operability can be obtained.
The molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of the cellulose ester is preferably 1.5 to 5.5, more preferably 2.0 to 5.0, and particularly preferably 2.5. It is -5.0, Most preferably, it is 3.0-5.0.

Cellulose acylate raw material cellulose used in the present invention includes cotton linter and wood pulp (hardwood pulp, softwood pulp), etc., and any cellulose acylate obtained from any raw material cellulose can be used, optionally mixed. May be. Detailed descriptions of these raw material celluloses can be found in, for example, Marusawa and Uda, “Plastic Materials Course (17) Fibrous Resin”, published by Nikkan Kogyo Shimbun (published in 1970), and the Japan Society of Invention and Innovation Technical Bulletin No. 2001. The cellulose described in No.-1745 (pages 7 to 8) can be used, and the optical film of the present invention is not particularly limited.
These cellulose esters can be used alone or in appropriate combination of two or more. For example, cotton linter-derived cellulose / wood pulp (coniferous) -derived cellulose / wood pulp (hardwood) -derived cellulose may be 100/0/0, 90/10/0, 85/15/0, 50/50/0, 20 / 80/0, 10/90/0, 0/100/0, 0/0/100, 80/10/10, 85/0/15, or 40/30/30.

<Method for forming cellulose ester film>
The cellulose ester film of the present invention is preferably produced by a solvent cast method. The solvent cast method is a method in which a solution (dope) in which a cellulose ester is dissolved in an organic solvent is cast on a support and then dried.
This will be specifically described below.

(1) Dissolution step Examples of the main solvent for dissolving the cellulose ester of the present invention include halogenated hydrocarbons, esters, ketones, ethers, alcohols and hydrocarbons, and these have a branched structure or a cyclic structure. It may be. The main solvent may have two or more functional groups of esters, ketones, ethers and alcohols (that is, —O—, —CO—, —COO—, —OH). Furthermore, the hydrogen atom in the hydrocarbon portion of the ester, ketone, ether and alcohol may be substituted with a halogen atom (particularly a fluorine atom).
In addition, as said halogenated hydrocarbon, a chlorinated hydrocarbon is more preferable, For example, a dichloromethane, chloroform, etc. are mentioned, A dichloromethane is further more preferable.

Examples of the ester include methyl formate, ethyl formate, methyl acetate, and ethyl acetate.
Examples of the ketone include acetone and methyl ethyl ketone.
Examples of the ether include diethyl ether, methyl tert-butyl ether, diisopropyl ether, dimethoxymethane, 1,3-dioxolane, 4-methyldioxolane, tetrahydrofuran, methyltetrahydrofuran, 1,4-dioxane and the like.
As said alcohol, methanol, ethanol, 2-propanol etc. are mentioned, for example.
Examples of the hydrocarbon include n-pentane, cyclohexane, n-hexane, benzene, and toluene.
In addition, the main solvent of the present invention indicates a solvent when it is composed of a single solvent, and when it is composed of a plurality of solvents, it is the solvent having the highest mass fraction among the constituent solvents. It shows that.

Examples of the organic solvent used in combination with these main solvents include halogenated hydrocarbons, esters, ketones, ethers, alcohols and hydrocarbons, which may have a branched structure or a cyclic structure. The organic solvent may have any two or more of ester, ketone, ether and alcohol functional groups (that is, —O—, —CO—, —COO—, —OH). Furthermore, the hydrogen atom in the hydrocarbon portion of the ester, ketone, ether and alcohol may be substituted with a halogen atom (particularly a fluorine atom).
As said halogenated hydrocarbon, a chlorinated hydrocarbon is more preferable, for example, a dichloromethane, chloroform, etc. are mentioned, A dichloromethane is further more preferable.
Examples of the ester include methyl formate, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate.
Examples of the ketone include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone.
Examples of the ether include diethyl ether, methyl tert-butyl ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, 4-methyldioxolane, tetrahydrofuran, methyltetrahydrofuran, anisole, and phenetole. Etc.
Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol, cyclohexanol, and 2-fluoro. Examples include ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol.
Examples of the hydrocarbon include n-pentane, cyclohexane, n-hexane, benzene, toluene, xylene and the like.
Examples of the organic solvent having two or more types of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol, 2-butoxyethanol, and methyl acetoacetate.
Furthermore, it is preferable to contain 5-30 mass% in all the solvents, More preferably, it is 7-25 mass%, More preferably, it contains 10-20 mass%.

  Specific examples of combinations of organic solvents preferably used as the solvent of the present invention are given below, but the combinations of organic solvents that can be employed in the present invention are not limited to these. In addition, the numerical value of a ratio means a mass part.

(A) Dichloromethane / methanol / ethanol / butanol = 80/10/5/5
(B) Dichloromethane / isobutyl alcohol = 90/10
(C) Dichloromethane / acetone / methanol / propanol = 80/5/5/10
(D) Dichloromethane / methanol / butanol / cyclohexane = 80/8/10/2
(E) Dichloromethane / methyl ethyl ketone / methanol / butanol = 80/10/5/5
(F) Dichloromethane / butanol = 90/10
(G) Dichloromethane / cyclopentanone / methanol / pentanol = 80/2/15/3
(H) Dichloromethane / methyl acetate / ethanol / butanol = 70/12/15/3
(I) Dichloromethane / cyclopentanone / ethanol / butanol = 85/7/3/5
(J) Dichloromethane / methanol / butanol = 83/15/2
(K) Dichloromethane = 100
(L) Acetone / ethanol / butanol = 80/15/5
(M) Methyl acetate / acetone / methanol / butanol = 75/10/10/5
(N) 1,3-dioxolane = 100
(O) Dichloromethane / methanol = 92/8
(P) Dichloromethane / methanol = 90/10
(Q) Dichloromethane / methanol = 87/13
(R) Dichloromethane / ethanol = 90/10

  In addition, the case where a non-halogen organic solvent is used as a main solvent is described in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical No. 2001-1745, published on March 15, 2001, Japan Institute of Invention and Innovation) and may be used as appropriate. it can.

  In the preparation of the cellulose ester solution (dope) of the present invention, the dissolution method is not particularly limited, and may be room temperature dissolution, cooling dissolution or high temperature dissolution, or a combination thereof. Regarding the preparation of the cellulose ester solution in the present invention, as well as the solution concentration and filtration steps involved in the dissolution step, the Invention Association Public Technical Bulletin No. 2001-1745 (issued March 15, 2001, Invention Association) The manufacturing processes described in detail on pages 22 to 25 are preferably used.

  The cellulose ester desirably has as few luminescent spots as possible when light is applied between a pair of polarizing plates arranged in crossed Nicols. As a means for reducing the bright spots due to light leakage as much as possible, typically, removal of unacetylated cellulose and filtration of molten cellulose ester to remove impurities can be mentioned. When removing impurities by filtration, it is preferable to melt and filter a composition containing a cellulose ester and a plasticizer described later, rather than melting the cellulose ester alone.

(2) Casting process As the method and equipment for producing the cellulose ester film of the present invention, for example, a known solution casting film forming method and solution casting film forming apparatus used for cellulose triacetate film production are used. As an example, the dope prepared in a dissolving machine (kettle) is temporarily stored in a storage machine, and the foam contained in the dope is defoamed for final preparation. The dope is fed from the dope discharge port to the pressurizing die through a pressurizing quantitative gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the number of rotations, and then the dope is cast from the die (slit) of the pressurizing die onto the support. As the support, a metal support or a metal drum running endlessly is used.
The support is preferably controlled in temperature. The preferred temperature range of the support is usually in the range of -20 ° C to 40 ° C.
Casting may be performed in one layer or in two or more layers (co-casting). In the case of co-casting, the cellulose ester solutions may have the same composition or different compositions. In the case of two or more layers, the polyrotaxane may be contained in at least one layer. A configuration in which the outer two layers contain a polyrotaxane in a configuration of three or more layers is also a preferable embodiment because both hardness and scratch resistance can be achieved.

(3) Drying and winding process Next, the dried or semi-dried dope film (also referred to as web) is peeled from the support. The peeled web is sandwiched between clips, transported by a tenter while maintaining 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. These are described in detail on pages 25 to 30 in the Invention Association Public Technical Bulletin No. 2001-1745 (issued March 15, 2001, Invention Association).

(4) Stretching process The cellulose ester film of the present invention may be stretched as necessary. The stretching direction may be the longitudinal direction or the width direction. The stretching may be single-stage stretching or multi-stage stretching. Any appropriate means (for example, roll, tenter) can be adopted as the stretching means.
Moreover, you may extend | stretch in 2 directions of a longitudinal direction and the width direction as needed. In this case, stretching in the longitudinal direction and the width direction may be performed simultaneously, or stretching in the longitudinal direction and the width direction may be performed in two stages.
The stretching temperature is typically in the range of the glass transition temperature (Tg) to (Tg + 150 ° C.) of the film. As the heating means, any appropriate means (for example, an infrared heater) can be used.
The stretched film is maintained at a temperature not higher than the final stretching temperature and not lower than (Tg−40 ° C.) for 0.01 to 5 minutes as necessary. By performing such heating and holding, it is possible to reduce the distribution of physical properties in the width direction and obtain a uniform film.

If necessary, the stretched film may be heat-set after stretching. Typically, heat setting is performed by holding the film for 0.5 to 300 seconds at a temperature higher than the final stretching temperature and not higher than (Tg-20 ° C).
The heat-set film is usually cooled to Tg or less, and the clip gripping portions at both ends of the film are cut and wound. At this time, it is preferable to perform a relaxation treatment of 0.1 to 10% in the width direction and / or the longitudinal direction at a temperature not higher than the final heat setting temperature and not lower than Tg. Moreover, it is preferable to cool gradually from the final heat setting temperature to Tg. Arbitrary appropriate means is employ | adopted as a means to cool and relax.

(5) Heat treatment step The cellulose ester film of the present invention may be heat treated as necessary.
When heat treatment is performed, the heat treatment temperature is preferably 160 ° C. or higher and lower than the melting point of the cellulose ester film, more preferably 180 ° C. or higher and lower than the melting point of the cellulose ester film −10 ° C.
The heat treatment time is preferably in the range of 5 seconds to 10 minutes, more preferably 10 seconds to 5 minutes.
There is no restriction | limiting in particular in a heating method, Well-known methods, such as a method using a warm air, an infrared heater, and a superheated roller, can be used.
When heat treatment is performed, the film width and / or length are kept constant, the film is stretched in the width and / or length direction, and the film is shrunk in the width and / or length direction using heat shrinkage. Although there is a method, any of the heat treatments of the present invention may be adopted.
The residual solvent amount of the cellulose ester film after the heat treatment is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and more preferably 0.3% by mass or less. More preferably, it is most preferably 0.1% by mass or less.

<Additives>
You may add an appropriate additive to the cellulose-ester film of this invention as needed. Specific examples of the additive include a heat stabilizer, a light stabilizer, a lubricant and the like in addition to the plasticizer, the ultraviolet absorber and the matting agent. The kind and amount of the additive used can be appropriately set according to the purpose. The amount of the additive used is typically 0.1 to 10 (weight ratio) or less with respect to 100 of the total solid content of the polymer film.
Examples of the plasticizer include phosphoric acid esters and carboxylic acid esters. Specific examples of the phosphate ester include triphenyl phosphate (TPP) and tricresyl phosphate (TCP). Representative examples of the carboxylic acid ester include phthalic acid ester and citric acid ester. Specific examples of the phthalic acid ester include dimethyl phthalate (DMP) and diethyl phthalate (DEP). Specific examples of the citrate ester include triethyl o-acetylcitrate (o-ACTE) and tributyl o-acetylcitrate (o-ACTB).
As other additives, for example, those described in JP-A-2006-138120 can be used.

  In the present invention, the thickness of the cellulose ester film is preferably 10 to 500 μm, more preferably 20 to 300 μm, and particularly preferably 30 to 200 μm. Within this range, the film strength and flexibility are compatible.

[surface treatment]
The optical film of the present invention can be appropriately treated with each functional layer (for example, undercoat layer, back layer, optical anisotropic layer, hard coat layer, antiglare layer, antireflection layer). Adhesion can be improved. The surface treatment includes glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, saponification treatment (acid saponification treatment, alkali saponification treatment), and glow discharge treatment and alkali saponification treatment are particularly preferable. The “glow discharge treatment” here is a treatment for subjecting the film surface to a plasma treatment in the presence of a plasma-excitable gas. The details of these surface treatment methods are described in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical No. 2001-1745, issued on March 15, 2001, Japan Institute of Invention) and can be used as appropriate.

  In order to improve the adhesion between the film surface and the functional layer, an undercoat layer (adhesive layer) may be provided on the optical film of the present invention in addition to or in place of the surface treatment. As for the undercoat layer, the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention), page 32 and page 45 (in the literature, “Easily Adhesive Layer” is described. These can be used as appropriate. Moreover, about the functional layer provided on the optical film of this invention, there exists description in 32 to 45 pages of invention association public technical bulletins (public technical number 2001-1745, issued March 15, 2001, invention association). These can be used as appropriate.

《Functional layer》
In some cases, the optical film of the present invention may be applied to a hard coat film, an antiglare film, and an antireflection film. For the purpose of improving the visibility of flat panel displays such as LCD, PDP, CRT, EL, etc., and adjusting the moisture permeability of the film, a hard coat layer, an antiglare layer on one or both sides of the optical film of the present invention, Any or all of the antireflective layer can be applied.

[Hard coat layer]
Embodiments relating to the hard coat layer are described in detail on pages 187 to 189 of JP-A-2005-104148, and can be preferably used in the optical film of the present invention.

[Anti-glare layer]
Embodiments relating to the antiglare layer are described in detail on pages 197 to 199 of JP-A-2005-104148, and can be preferably used in the optical film of the present invention.

[Antireflection layer]
Embodiments relating to the antireflection layer are described in detail in JP-A-2005-104148, pages 189 to 197, and can be preferably used in the optical film of the present invention.

[Polymer layer]
Examples of polymers used as the polymer layer include polyolefins (eg, polyethylene, polypropylene, norbornene-based polymers), polycarbonate, polyarylate, polysulfone, polyvinyl alcohol, polymethacrylic acid ester, polyacrylic acid ester, polyvinylidene chloride, and Cellulose esters (eg, cellulose triacetate, cellulose diacetate) are included, and as the polymer, a copolymer or a polymer mixture of these polymers may be used. These polymer layers can also be formed by applying a polymer solution on the optical film of the present invention. When casting the optical film of the present invention, a sequential casting method or a co-casting method is used. It can also be formed. Moreover, it can also carry out by laminating | stacking the polymer film and the optical film of this invention which were produced beforehand using an adhesive or an adhesive agent.

<Optical compensation film>
The optical film of the present invention can be used as an optical compensation film in some cases. The “optical compensation film” generally means an optical material having optical anisotropy, which is used in a display device such as a liquid crystal display device, and is a retardation film, a retardation plate, an optical compensation film, an optical compensation. Synonymous with sheet. In a liquid crystal display device, an optical compensation film is used for the purpose of improving the contrast of a display screen or improving viewing angle characteristics and color.
The optical film of the present invention can also be used as an optical compensation film as it is. Also, a plurality of optical films of the present invention can be laminated, or an optical film of the present invention and a film outside of the present invention can be laminated to adjust Re and Rth as appropriate, and used as an optical compensation film. Lamination of the film can be performed using a pressure-sensitive adhesive or an adhesive.
In some cases, the optical film of the present invention may be used as a support for an optical compensation film, and an optical anisotropic layer made of liquid crystal or the like may be provided thereon to be used as an optical compensation film. The optically anisotropic layer applied to the optical compensation film of the present invention may be formed from, for example, a composition containing a liquid crystal compound or may be formed from a cellulose acylate film having birefringence.
The liquid crystal compound is preferably a discotic liquid crystal compound or a rod-like liquid crystal compound.

[Discotic liquid crystalline compounds]
Examples of the discotic liquid crystalline compound that can be used as the liquid crystalline compound in the present invention include various documents (for example, C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 ( 1981); Edited by Chemical Society of Japan, Quarterly Chemical Review, No. 22, Chemistry of Liquid Crystal, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm. , page 1794 (1985); J. Zhang et al., J. Am. Chem. Soc., vol. 116, page 2655 (1994)).
In the optically anisotropic layer, the discotic liquid crystalline molecules are preferably fixed in an aligned state, and most preferably fixed by a polymerization reaction. Further, 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. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Discotic liquid crystalline molecules having a polymerizable group are disclosed in JP-A No. 2001-4387.

[Bar-shaped liquid crystalline compound]
Examples of the rod-like liquid crystalline compound that can be used as the liquid crystalline compound in the present invention include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexane. , Cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles. Further, as the rod-like liquid crystal compound, not only the above low molecular liquid crystal compound but also a polymer liquid crystal compound can be used.

  In the optically anisotropic layer, the rod-like liquid crystalline molecules are preferably fixed in an aligned state, and most preferably fixed by a polymerization reaction. Examples of polymerizable rod-like liquid crystalline compounds that can be used in the present invention include, for example, Makromol. Chem., 190, 2255 (1989), Advanced Materials, 5, 107 (1993), US Pat. Nos. 683,327, 5,622,648, 5,770,107, WO 95/22586, 95/24455, 97/00600, 98/23580 pamphlet, 98/52905 pamphlet, JP-A-1-272551, JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, and JP-A-2001-328773. Compounds described in publications and the like are included.

(Optically anisotropic layer made of polymer film)
The optically anisotropic layer may be formed from a polymer film. The polymer film can be formed from a polymer that can exhibit optical anisotropy. Examples of the polymer that can exhibit the optical anisotropy include polyolefin (eg, polyethylene, polypropylene, norbornene-based polymer), polycarbonate, polyarylate, polysulfone, polyvinyl alcohol, polymethacrylic acid ester, polyacrylic acid ester, and Cellulose esters (eg, cellulose triacetate, cellulose diacetate) are included. Moreover, as the polymer, a copolymer or polymer mixture of these polymers may be used. In order to increase optical anisotropy, the film can be stretched after the polymer film layer is formed on the optical film of the present invention.

"Polarizer"
The optical film or optical compensation film of the present invention can be used as a protective film for a polarizing plate (polarizing plate of the present invention). The polarizing plate of the present invention comprises a polarizing film and two polarizing plate protective films (cellulose acylate films) that protect both surfaces thereof, and the optical film or optical compensation film of the present invention is used as at least one polarizing plate protective film. be able to. Moreover, the optical film of this invention can be bonded by a polarizing film and roll-to-roll using an adhesive agent.

  When the optical film of the present invention is used as the polarizing plate protective film, the optical film of the present invention is hydrophilized by applying the surface treatment (also described in JP-A-6-94915 and 6-118232). For example, glow discharge treatment, corona discharge treatment, or alkali saponification treatment is preferably performed. In particular, alkali saponification treatment is most preferably used as the surface treatment.

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

  In general, a liquid crystal display device includes four polarizing plate protective films because a liquid crystal cell is provided between two polarizing plates. The optical film of the present invention can be suitably used for any of the four polarizing plate protective films. Among them, the optical film of the present invention is particularly preferably used as an outer protective film that is not disposed between the polarizing film and the liquid crystal layer (liquid crystal cell) in the liquid crystal display device. In this case, the hard coat layer, the antiglare layer, the reflection A prevention layer or the like can be provided.

<Liquid crystal display device>
The optical film, optical compensation film, and polarizing plate of the present invention can be used for liquid crystal display devices in various display modes.

  Each liquid crystal mode in which these films are used will be described below. These liquid crystal display devices may be any of a transmissive type, a reflective type, and a transflective type.

(TN type liquid crystal display device)
The optical film of the present invention can 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. With respect to the optical compensation film used in the TN type liquid crystal display device, each of JP-A-3-9325, JP-A-6-148429, JP-A-8-50206 and JP-A-9-26572, and Mori. It is described in other papers (Jpn.J.Appl.Phys.Vol.36 (1997) p.143 and Jpn.J.Appl.Phys.Vol.36 (1997) p.1068).

(STN type liquid crystal display device)
The optical 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 for the STN type liquid crystal display device is described in JP-A No. 2000-105316.

(VA type liquid crystal display device)
The optical film of the present invention can be used as an optical compensation film for a VA liquid crystal display device having a VA mode liquid crystal cell or as a support for the optical compensation film. 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 and ECB liquid crystal display device)
The optical film of the present invention can be used as an IPS liquid crystal display device having IPS mode and ECB mode liquid crystal cells, an optical compensation film for an ECB liquid crystal display device, a support for the optical compensation film, or a protective film for a polarizing plate. it can. In these modes, the liquid crystal material is aligned substantially in parallel during black display, and black is displayed by aligning liquid crystal molecules parallel to the substrate surface in the absence of voltage.

(OCB type liquid crystal display device and HAN type liquid crystal display device)
The optical 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 retardation 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 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 An optical compensation film used for an OCB type liquid crystal display device or a HAN type liquid crystal display device is described in JP-A-9-197397. It is also described in Mori et al. (Jpn. J. Appl. Phys. Vol. 38 (1999) p. 2837).

(Reflective liquid crystal display)
The optical 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 is described in JP-A-10-123478, WO98 / 48320 pamphlet, and Japanese Patent No. 3022477. The optical compensation film used in the reflective liquid crystal display device is described in International Publication No. 00/65384 pamphlet.

(Other liquid crystal display devices)
The optical 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 (Axially Symmetric Aligned 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 are described in Kume et al. (Kume et al., SID 98 Digest 1089 (1998)).

  In order to describe the present invention in detail, the following examples are given for explanation, but the present invention is not limited thereto. Unless otherwise specified, “part” and “%” are based on mass.

[Preparation of polyrotaxane and crosslinked polyrotaxane]
The polyrotaxane and the crosslinked polyrotaxane were prepared with reference to the following preparation methods described in Japanese Patent No. 2810264 and Japanese Patent No. 3475252.
“Cyclodextrin as a cyclic molecule, polyethylene glycol as a linear molecule, 2,4-dinitrophenyl group as a blocking group, acetyl group as a hydrophobic group, and acryloyl group as an unsaturated double bond group. The preparation method is described.
For subsequent blocking treatment, both ends of polyethylene glycol are modified with amino groups to obtain polyethylene glycol derivatives. A polyrotaxane is prepared by mixing α-cyclodextrin and a polyethylene glycol derivative. At the time of preparation, when the maximum inclusion amount is 1, for example, the mixing time is 1 to 48 hours so that the inclusion amount is 0.001 to 0.6 with respect to 1, and the mixing temperature is 0 ° C. to It can be 100 degreeC.
Generally, up to 230 α-cyclodextrins can be packaged with respect to an average molecular weight of 20,000 of polyethylene glycol. Therefore, this value is the maximum inclusion amount. The above conditions are such that the average molecular weight of polyethylene glycol is 20,000, and α-cyclodextrin has an average of 60 to 65 (63), that is, a maximum inclusion amount of 0.26 to 0.29 (0.28). This is a condition for inclusion by value. The inclusion amount of α-cyclodextrin can be confirmed by NMR, light absorption, elemental analysis and the like.
By reacting the obtained polyrotaxane with 2,4-dinitrofluorobenzene dissolved in DMF, a blocked polyrotaxane (unmodified polyrotaxane) is obtained.
Next, the resulting unmodified polyrotaxane is modified with a acetyl group, which is a hydrophobic group, using acetic anhydride to obtain a hydrophobized modified polyrotaxane.
Further, the unmodified hydroxyl group of the cyclodextrin ring of the hydrophobized modified polyrotaxane is modified with acryloyl chloride with acryloyl chloride to make the polyrotaxane hydrophobized and have an unsaturated double bond group. "

[Preparation of Unmodified Polyrotaxane (PR-1)]
<Preparation of end-capped polyrotaxane>
4.5 g of polyethylene glycol bisamine having a number average molecular weight of 20,000 and 18.0 g of α-cyclodextrin were added to 150 mL of water and dissolved by heating to 80 ° C. The solution was cooled and allowed to stand at 5 ° C. for 16 hours. The produced white paste-like precipitate was collected and dried.

  To the dried product, a mixed solution of 12.0 g of 2,4-dinitrofluorobenzene and 50 g of dimethylformamide was added and stirred at room temperature for 5 hours. The reaction mixture was dissolved by adding 200 mL of dimethyl sulfoxide (DMSO), and then poured into 3750 mL of water to separate a precipitate. The precipitate was redissolved in 250 mL of DMSO and then poured again into 3500 mL of 0.1% saline to separate the precipitate. The precipitate was washed with water and methanol three times each, and then vacuum-dried at 50 ° C. for 12 hours, whereby polyethylene glycol bisamine was included in α-cyclodextrin in a skewered manner, and both terminal amino groups had 2 Thus, 2.0 g of an inclusion compound to which a 4-dinitrophenyl group was bonded was obtained. This was designated as unmodified polyrotaxane (PR-1).

The obtained inclusion compound (end-blocked blocked polyrotaxane) was subjected to ultraviolet light absorption measurement and ¹ H-NMR measurement, and the inclusion amount of α-cyclodextrin was calculated. The inclusion amount was 72. there were.
The inclusion amount can be calculated from ultraviolet absorption measurement and ¹ H-NMR measurement. Specifically, in the ultraviolet absorption measurement, the molar absorption coefficient at 360 nm of each of the synthesized inclusion compound and 2,4-dinitroaniline is calculated. The inclusion amount of cyclodextrin was calculated by measurement. Moreover, in < ¹ > H-NMR measurement, it computed from the integral ratio of the hydrogen atom of a polyethylene part, and the hydrogen atom of a cyclodextrin part.

[Preparation of Hydrophobized Modified Polyrotaxane (PR-2)]
<Acetyl modification of blocked polyrotaxane with end-capping>
1 g of the unmodified polyrotaxane (PR-1) synthesized above was dissolved in 50 g of an 8% solution of lithium chloride / N, N-dimethylacetamide. Thereto were added 6.7 g of acetic anhydride, 5.2 g of pyridine, and 100 mg of N, N-dimethylaminopyridine, and the mixture was stirred overnight at room temperature. The reaction solution was poured into methanol, and the precipitated solid was separated by centrifugation. The separated solid was dried and then dissolved in acetone. The solution was poured into water, and the precipitated solid was separated by centrifugation and dried to obtain 1.2 g of acetyl-modified hydrophobized modified polyrotaxane (PR-2).

The obtained acetyl-modified polyrotaxane was subjected to ¹ H-NMR measurement, and the amount of acetyl introduced was calculated. The amount introduced was 75%.

[Preparation of Cross-linked Polyrotaxane (PR-3)]
<Introduction of polymerizable group>
[Preparation of Crosslinked Polyrotaxane Compound (PR-3)]
A solution prepared by dissolving 0.18 g of cyanuric chloride in 20 g of acetone was slowly added dropwise to 80 g of vigorously stirred ice water. Thus, a cyanuric chloride dispersion (liquid A) was obtained. Separately, a solution (liquid B) was prepared by dissolving 2.4 g of α-cyclodextrin and 0.53 g of sodium carbonate in 200 g of water.
The liquid A was added dropwise to the liquid B being slowly stirred.
Thereafter, the temperature of the liquid was raised to 50 ° C., and stirring was continued for 6 hours. Thereafter, the solution temperature was lowered to 25 ° C. to obtain a solution (Liquid C). Liquid C was mixed with a solution obtained by dissolving 10 g of polyethylene glycol (average molecular weight 20000) in 700 g of water, and the mixture was slowly stirred at 25 ° C. for 24 hours. Furthermore, this liquid was concentrated using an evaporator until the whole became 500 g to obtain a solution (liquid D). A solution (liquid E) in which 0.46 g of 1-aminododecane was dissolved in 500 g of tetrahydrofuran was mixed with the liquid D and stirred at 80 ° C. for 6 hours. Further, 0.21 g of sodium carbonate was dissolved in this liquid to obtain a solution (liquid F).
A solution obtained by dissolving 0.21 g of methacrylic acid chloride in 20 g of tetrahydrofuran was added to the liquid F containing triethylamine, and the mixture was reacted at 50 ° C. for 6 hours with stirring. The produced triethylamine hydrochloride was filtered off to obtain a solution (liquid G). The solvent of this liquid G was removed using an evaporator to obtain a crosslinked polyrotaxane compound (PR-3).

[Preparation of Hydrophobized Modified Crosslinked Polyrotaxane (PR-4)]
<Acetyl modification of blocked polyrotaxane with end-capping>
1 g of the crosslinked polyrotaxane (PR-3) synthesized above was dissolved in 50 g of an 8% solution of lithium chloride / N, N-dimethylacetamide. Thereto were added 6.7 g of acetic anhydride, 5.2 g of pyridine, and 100 mg of N, N-dimethylaminopyridine, and the mixture was stirred overnight at room temperature. The reaction solution was poured into methanol, and the precipitated solid was separated by centrifugation. The separated solid was dried and then dissolved in acetone. The solution was poured into water, and the precipitated solid was separated by centrifugation and dried to obtain 1.2 g of acetyl-modified hydrophobized modified crosslinked polyrotaxane (PR-4).

The obtained acetyl-modified polyrotaxane was subjected to ¹ H-NMR measurement, and the amount of acetyl introduced was calculated. The amount introduced was 75%.

[Cellulose ester]
In Examples-1 to 20 and Comparative Example-1, the following cellulose esters were used. Each cellulose ester was heated to 120 ° C. and dried to adjust the water content to 0.5% by mass or less before use.

-Cellulose acylate C-1:
A cellulose acetate powder having a substitution degree of 2.85 was used. Cellulose ester C-1 has a viscosity average degree of polymerization of 300, a substitution degree of acetyl group at the 6-position of 0.89, an acetone extract of 7% by mass, a mass average molecular weight / number average molecular weight ratio of 2.3, and a water content of 0. .2% by mass, 6% by mass Viscosity in dichloromethane solution is 305 mPa · s, residual acetic acid content is 0.1% by mass or less, Ca content is 65 ppm, Mg content is 26 ppm, iron content is 0.8 ppm, sulfuric acid The ion content was 18 ppm, the yellow index was 1.9, and the amount of free acetic acid was 47 ppm. The average particle size of the powder was 1.5 mm, and the standard deviation was 0.5 mm.

-Cellulose acylate C-2:
A cellulose ester powder having a substitution degree of 2.25 was used. Cellulose 5rw. The viscosity average polymerization degree of C-2 was 300.
-Cellulose acylate C-3:
A cellulose ester powder having a total substitution degree of 2.25, an acetyl substitution degree of 1.45, and a purpionyl substitution degree of 0.8 was used. Cellulose 5rw. The viscosity average polymerization degree of C-3 was 320.
-Cellulose acylate C-4:
A cellulose ester powder having a total substitution degree of 3.0, an acetyl substitution degree of 2.2, and a purpionyl substitution degree of 0.8 was used. Cellulose 5rw. The viscosity average polymerization degree of C-4 was 300.

-Cellulose acylate C-5:
A cellulose ester powder having a total substitution degree of 3.0, an acetyl substitution degree of 2.25, and a benzoyl substitution degree of 0.75 was used. Cellulose 5rw. The viscosity average polymerization degree of C-5 was 280.
-Cellulose acylate C-6:
A cellulose ester powder having a total substitution degree of 3.0, an acetyl substitution degree of 2.25, and a long-chain alkyl substitution degree of 6 carbon atoms of 0.75 was used. Cellulose 5rw. The viscosity average polymerization degree of C-6 was 315.
-Cellulose acylate C-7:
A cellulose ester powder having a total substitution degree of 3.0, an acetyl substitution degree of 2.25, and a long chain alkyl substitution degree of 12 carbon atoms of 0.75 was used. Cellulose 5rw. The viscosity average polymerization degree of C-7 was 310.

-Cellulose acylate C-8:
Cellulose ester powder having a total substitution degree of 3.0, an acetyl substitution degree of 2.25, and a long-chain alkyl substitution degree of 18 carbon atoms of 0.75 was used. Cellulose 5rw. The viscosity average polymerization degree of C-8 was 320.

[Replacement degree]
The acyl substitution degree of cellulose acylate was determined by ¹³ C-NMR by the method described in Carbohydr. Res. 273 (1995) 83-91 (Tezuka et al.).

[Degree of polymerization]
After the produced cellulose acylate was absolutely dried, about 0.2 g was precisely weighed and dissolved in 100 mL of a mixed solvent of dichloromethane: ethanol = 9: 1 (mass ratio). This was measured with an Ostwald viscometer at 25 ° C. for the number of seconds to drop, and the degree of polymerization DP was determined by the following equation.
ηrel = T / T0 [η] = ln (ηrel) / C
DP = [η] / Km
[In the formula, T is the number of seconds that the sample is dropped, T0 is the number of seconds that the solvent is dropped, ln is the natural logarithm, C is the concentration (g / L), and Km is 6 × 10 ⁻⁴ . ]

[Example-1]
<Preparation of polymer solution (dope)>
1) Cellulose ester: C-1 15.0 parts by mass 2) Plasticizer: Dibutyl phosphate 0.9 part by mass 3) Plasticizer: Triphenyl phosphate 0.9 part by mass 4) Solvent: Dichloromethane / methanol / butanol ( 83/15/2 parts by mass) Mixed solvent 85.0 parts by mass 5) Fine particles: Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7)
0.08 part by mass 6) 3.0 parts by mass of polyrotaxane compound (PR-1)

A solvent and fine particles were put into a 400 ml stainless container that had a stirring blade and could be sealed, stirred and dispersed, and then the cellulose ester and two types of plasticizer were gradually added. After the addition, the mixture was stirred at room temperature for 2 hours. Thereafter, stirring was stopped and swelling was performed for 3 hours.
The sample was then heated to 50 ° C., further sealed and heated to 90 ° C., and stirred for 15 minutes for complete dissolution. Next, the temperature was lowered to room temperature, a polyrotaxane compound was added, and the mixture was stirred for 30 minutes. Subsequently, the obtained cellulose ester solution was filtered through a filter paper (# 63, manufactured by Toyo Filter Paper Co., Ltd.) having an absolute filtration accuracy of 10 μm to obtain a polymer solution.

<Production of film (casting method A)>
The obtained polymer solution was heated to 30 ° C., and cast on a mirror surface stainless steel support set to 15 ° C. using a casting Giesser. The casting speed was 50 cm / min, and the coating width was 200 mm. The temperature of the entire casting part was set to 15 ° C. After casting, the film was peeled from the support.
The volatile content at the time of peeling was about 27% by mass with respect to the dry film. Thereafter, a drying air of 45 ° C. was blown. Next, it was dried at 110 ° C. for 5 minutes and further at 140 ° C. for 10 minutes to obtain a transparent cellulose ester film having a thickness of 80 μm. The amount of residual solvent was 0.4 mass%.

[Evaluation of optical film]
(1) Scratch resistance evaluation: Steel wool test After the cellulose ester film was conditioned for 2 hours under the conditions of a temperature of 25 ° C. and a relative humidity of 60%, the steel wool was reciprocated twice at a ground contact area of 1 cm ² and a load of 20 g. The scratches were determined visually under a fluorescent lamp, and the following four-level evaluation was performed.
4: No scratches are observed 3: Slight scratches are observed 2: Scratches are observed 1: Clear scratches are observed

(2) Tear strength A 50mm x 64mm sample was conditioned at 23 ° C and 65% relative humidity for 2 hours, and the load required for tearing according to ISO 6383 / 2-1983 using a light load tear strength tester (Toyo Seiki Seisakusho). Measured and averaged in the MD and TD directions for evaluation.

(3) Folding strength The sample 120 mm × 120 mm was conditioned at 23 ° C. and relative humidity 65% for 2 hours, and the number of reciprocations until it was cut by bending according to ISO8776-1988 was measured.

(4) Measurement of haze The haze of the obtained cellulose ester film was measured using a haze meter MODEL1001DP (manufactured by Nippon Denshoku Industries Co., Ltd.).
The results are shown in Table-1.

[Examples 2 to 10, Comparative Example 1]
Examples 2 to 10 and Comparative Example 1 were carried out in the same manner as Example 1 except that the type and amount of the polyrotaxane compound were changed as shown in Table-1. The results are shown in Table-1.

[Examples 11 to 17]
Examples 11 to 17 were carried out in the same manner as Example-6 except that the type of cellulose ester was changed as shown in Table-1. The results are shown in Table-1.

[Example-18]
Examples 11 to 17 were carried out in the same manner as Example-6 except that the casting method was changed as follows. The results are shown in Table-1.

[Production of Film (Casting Method B)]
The polymer solution of Example-1 was heated to 30 ° C., and cast on a mirror surface stainless steel support set to −7 ° C. using a casting Giesser. The casting speed was 50 cm / min, and the coating width was 200 mm. The temperature of the entire casting part was set to 15 ° C. After casting, the film was peeled from the support before drying.
The volatile content at the time of peeling was about 270% by mass with respect to the dry film. Thereafter, a drying air of 45 ° C. was blown. Next, it was dried at 110 ° C. for 15 minutes and further at 140 ° C. for 10 minutes to obtain a transparent cellulose ester film having a thickness of 80 μm. The residual solvent amount was 0.5% by mass.

[Example-19]
The cellulose ester film obtained in Example-6 was 30% fixed-end uniaxially stretched in the casting direction and the orthogonal direction, and then 4% fixed-end uniaxially stretched in the casting direction. The film temperature during stretching was 140 ° C., and the stretching speed was 10% / second.
The cellulose ester film thus obtained was evaluated in the same manner as in Example-1. The results are shown in Table-1.

[Example-20]
The cellulose ester film obtained in Example-13 was uniaxially stretched by 40% free end in the casting direction at 140 ° C. and a stretching speed of 10% / second, and then the four sides of the sample film were fixed and fixed at 230 ° C. for 2 minutes. Heat treated.
The cellulose ester film thus obtained was evaluated in the same manner as in Example-1. The results are shown in Table-1.

From the results shown in Table 1, the following is clear.
By introducing polyrotaxane into the cellulose acylate film, the scratch resistance, tear resistance and folding strength can be improved. (Example 1 and Comparative Example 1)
Polyrotaxane can suppress an increase in haze by introducing a hydrophobic modification. (Example 2 with respect to Example 1)
The amount of polyrotaxane introduced is 0.1 to 40%, which can improve the significant scratch resistance, tear resistance, and folding strength. (Examples 3 to 8)
Similarly, the cross-linked polyrotaxane can improve the scratch resistance, tear resistance, and folding strength. (Example 9, Example 10)
By introducing the same polyrotaxane in various cellulose ester films, the scratch resistance, tear resistance, and folding resistance can be improved. (Examples 11 to 17)
In both the stretching methods A and B, the introduction of polyrotaxane can improve the scratch resistance, tear resistance, and folding strength. (Example 6 and Example 18)
It is a cast film and a film that has been heat-treated after casting, and even when polyrotaxane is introduced, the tear resistance and folding resistance can be improved. (Examples 19 and 20)

  Next, the present invention will be described with reference to an example of an antireflection hard coat film obtained by laminating a hard coat layer and an antireflection layer (low refractive index layer) as a base material containing polyrotaxane prepared as described above.

[Example-21]
[Preparation of hard coat coating solution (HCL-1)]
PET-30 292.5 parts Irgacure 907 7.5 parts MIBK 490.0 parts MEK 210.0 parts

The compounds other than those used in the hard coat coating solution are shown below.
PET-30: A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (manufactured by Nippon Kayaku Co., Ltd.)
Irgacure 907: Photopolymerization initiator (manufactured by Ciba Japan Co., Ltd.)
MIBK: Methyl isobutyl ketone MEK: Methyl ethyl ketone

<Preparation of coating solution for low refractive index layer>
[Preparation of Sol Solution a]
In a reactor equipped with a stirrer and a reflux condenser, 120 parts by mass of methyl ethyl ketone, 100 parts by mass of acryloxypropyltrimethoxysilane “KBM-5103” (manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts by mass of diisopropoxyaluminum ethyl acetoacetate After adding a part and mixing, 30 mass parts of ion-exchange water was added, and it was made to react at 60 degreeC for 4 hours, Then, it cooled to room temperature and obtained the sol liquid a. The mass average molecular weight was 1800, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100% by mass. From the gas chromatography analysis, the raw material acryloxypropyltrimethoxysilane did not remain at all.

[Preparation of Hollow Silica Fine Particle Dispersion (A-1)]
Hollow silica fine particle sol (particle size of about 40 to 50 nm, shell thickness of 6 to 8 nm, refractive index of 1.31, solid content concentration of 20% by mass, main solvent isopropyl alcohol, according to Preparation Example 4 of JP 2002-79616 A Prepared by changing the particle size) 500 parts by mass, 30 parts by mass of acryloyloxypropyltrimethoxysilane “KBM-5103” {manufactured by Shin-Etsu Chemical Co., Ltd.}, and diisopropoxyaluminum ethyl acetoacetate “Kelope EP-12 “{Hope Pharmaceutical Co., Ltd.} 1.5 parts by mass was added and mixed, and then 9 parts by mass of ion-exchanged water was added. After making it react at 60 degreeC for 8 hours, it cooled to room temperature, 1.8 parts of acetylacetone was added, and the hollow silica dispersion liquid (A-1) was obtained. The resulting hollow silica dispersion had a solid content concentration of 18% by mass and a refractive index after solvent drying of 1.31.

[Preparation of coating solution for low refractive index layer (LL-1)]
44.0 parts by mass of a fluorine-containing copolymer (P-3) (weight average molecular weight of about 50000) described in JP-A-2004-45462, dipentaerythritol pentaacrylate and dipentaerythritol with respect to 100 parts by mass of methyl ethyl ketone Hexaacrylate mixture “DPHA” {manufactured by Nippon Kayaku Co., Ltd.} 6.0 parts by mass, terminal methacrylate group-containing silicone “RMS-033” (manufactured by Gelest) 3.0 parts by mass, “Irgacure 907” {Ciba Japan Co., Ltd.} was added and dissolved in an amount of 3.0 parts by mass. Thereafter, 195 parts by mass of the hollow silica fine particle dispersion (A-1) (39.0 parts by mass as the solid content of silica + surface treatment agent) and 17.2 parts by mass of the sol liquid a (5.0 parts by mass as the solid part) were added. Added. The coating liquid for low refractive index layer (LL-1) was prepared by diluting with cyclohexane and methyl ethyl ketone so that the solid content concentration of the entire coating liquid was 6% by mass and the ratio of cyclohexane and methyl ethyl ketone was 10:90.
In addition, the refractive index after hardening of the coating film obtained by apply | coating this coating liquid was 1.38.

<Preparation of hard coat film>
[Coating of hard coat layer]
Using the slot die coater described in FIG. 1 of Japanese Patent Application Laid-Open No. 2003-211052, the 80 μm thick triacetyl cellulose film produced in Example 1 was unwound in a roll form and coated with a hard coat layer. The liquid (HCL-1) was applied to a dry film thickness of 6 μm, dried at 30 ° C. for 15 seconds and at 90 ° C. for 20 seconds, and further purged with nitrogen to 160 W / cm in an atmosphere with an oxygen concentration of 100 ppm or less. The “air-cooled metal halide lamp” {manufactured by Eye Graphics Co., Ltd.} was used to produce a hard coat film (HC-1) in which the coating layer was cured by irradiating with an ultraviolet ray with an irradiation amount of 70 mJ / cm ^2. I took it.

  Next, the substrate was changed to those shown in Example-1 to Example-6, Example-9, Example-10, and Comparative Example-1, and hard coat films (HC-2) to ( HC-5) was prepared.

[Coating of low refractive index layer]
The coating liquid for low refractive index layer (LL-1) is further applied on the hard coat layers of the hard coat films (HC-1) to (HC-5) produced as described above, as shown in Japanese Patent Application Laid-Open No. 2003-211052. Using the slot die coater described in No. 1, wet coating was performed so that the dry film thickness of the low-refractive index layer was 100 nm, drying at 60 ° C. for 50 seconds, and nitrogen purge to further reduce the oxygen concentration to 100 ppm or less. Using a 240 W / cm “air-cooled metal halide lamp” {manufactured by Eye Graphics Co., Ltd.}, irradiating with an ultraviolet ray with an irradiation amount of 400 mJ / cm ² to form a low refractive index layer and winding it up, antireflection properties Hard coat film sample No. 101-105 were produced.

[Evaluation of antireflection film]
The antireflection hard coat film was evaluated by the following method, and the results are shown in Table 2.
In addition, evaluation of haze was measured by the method similar to said [evaluation of an optical film] (3).

(1) Average reflectance After the surface of the antireflection hard coat film on which the hard coat layer is not laminated is roughened with sandpaper, light absorption treatment with black ink (transmittance at 380 to 780 nm is less than 10%) ) Was performed on a black table under the following conditions.
A spectrophotometer “V-550” (manufactured by JASCO Corporation) is fitted with an adapter “ARV-474” and has a specular reflectance with an output angle of −5 ° at an incident angle of 5 ° in the wavelength region of 380 to 780 nm. The average reflectance of 450 to 650 nm was used for the result.

(2) Pencil hardness evaluation Pencil hardness evaluation described in JIS K 5400 was performed as an index of scratch resistance. After conditioning the anti-reflective hard coat film at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, using a pencil for testing of 2H to 5H specified in JIS S 6006, with a load of 4.9 N with a pencil The scratch test was repeated 5 times, and the sample was allowed to stand for 24 hours under conditions of a temperature of 25 ° C. and a humidity of 60% RH, and then evaluated according to the following criteria.
OK: No more than 2 scratches in the evaluation of n = 5 NG: No less than 3 scratches in the evaluation of n = 5

(3) Thickness of hard coat layer Using a micro gauge thickness meter manufactured by Mitutoyo Corporation, the thickness of the entire hard coat film and the thickness of the transparent plastic film substrate are measured. The thickness of the hard coat layer was calculated by subtracting the thickness.

From the results shown in Table 2, the following is clear.
Antireflective hard coat film using cellulose ester film containing polyrotaxane as a base material has higher pencil hardness and reflective than antireflective hard coat film using cellulose ester film not containing polyrotaxane as a base material. Also excellent in prevention.

<Production of polarizing plate, liquid crystal display device>
Examples 11-1 to 11-4
Iodine is adsorbed on polyvinyl alcohol and stretched on one side of a polarizer prepared by dipping in a 1.5 mol / L, 55 ° C. NaOH aqueous solution for 2 minutes, neutralized, washed with water, and 80 μm thick triacetyl. A cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd.) was adhered, and the antireflection film sample Nos. 101 to 104 were bonded to each other to prepare a polarizing plate with antireflection.
Using this polarizing plate, a liquid crystal display device having an antireflection layer disposed on the outermost layer was produced. The reflectance was low, the reflection of external light was small, the reflected image was not noticeable, and excellent visibility was obtained. Yes.

Claims (12)

  An optical film comprising a cellulose ester as a main component and a polyrotaxane.   The optical film according to claim 1, wherein the content of the polyrotaxane is 0.1 to 30 parts by mass with respect to the polymer.   The optical film according to claim 1 or 2, wherein the cyclic molecule of the polyrotaxane is cyclodextrin.   The cyclic molecule of the polyrotaxane is a cyclodextrin in which a hydroxyl group is modified by a hydrophobic modifying group, and the degree of modification by the hydrophobic modifying group is 0.02 when the maximum number of hydroxyl groups of the cyclodextrin that can be modified is 1. It is the above, The optical film of Claim 3 characterized by the above-mentioned.   The optical film according to claim 1, wherein the polyrotaxane is a crosslinked polyrotaxane.   The OH group of cellulose is partially or entirely substituted with an acyl group, and the acyl group substitution degree is in the range of 2.0 to 3.0. Optical film.   The optical film according to claim 1, wherein at least one of the acyl groups is an acyl group having 3 to 20 carbon atoms.   The optical film according to claim 1, wherein the polyrotaxane linear molecule has a polyethylene glycol chain.   An optical functional film comprising the optical film according to claim 1 as a base material, and further having a functional layer laminated thereon.   The functional layer is any one of a hard coat layer, an antiglare layer, an antireflection layer, a polymer layer, and an optical compensation layer, or a plurality of layers selected from these layers. Optical functional film.   A polarizing plate, wherein the optical film according to claim 1 is used as a polarizing plate protective film.   An image display device comprising the optical film according to claim 1.