JP5053583B2 - Cellulose ester film laminate and production method thereof, polarizing plate, optical compensation film, antireflection film, and liquid crystal display device - Google Patents

Description

  The present invention relates to a laminate in which a protective film is laminated on a cellulose ester film and a method for producing the same. The present invention also relates to a polarizing plate, an optical compensation film, an antireflection film, and a liquid crystal display device produced using the cellulose ester film laminate.

  Conventionally, when manufacturing a cellulose triacetate film used in a liquid crystal display device, a solution in which cellulose triacetate is dissolved in a chlorinated organic solvent such as dichloromethane and cast on a substrate and dried to form a film. The casting method is mainly implemented. Among chlorinated organic solvents, dichloromethane is preferably used because it is a good solvent for cellulose triacetate, has a low boiling point (about 40 ° C.), and can be easily dried in a film forming process or a drying process. However, in recent years, from the viewpoint of environmental conservation, it has been strongly demanded to suppress the discharge of organic solvents including chlorinated organic solvents. For this reason, the stricter closed system is adopted to prevent the organic solvent from leaking out of the system, or even if the organic solvent leaks from the film forming process, the organic solvent is adsorbed through the gas absorption tower before being released to the outside air. Measures are taken so that the organic solvent is hardly discharged by performing a process such as burning with thermal power or decomposing with an electron beam. However, even if these measures were taken, further non-emission was not achieved, so further improvement was required.

  Therefore, as a film forming method that does not use an organic solvent, a method of melt-forming cellulose ester has been developed (see, for example, Patent Documents 1 and 2). In these methods, the melting point is lowered by elongating the carbon chain of the acetyl group of cellulose triacetate to facilitate melt film formation. Specifically, melt film formation is enabled by changing the cellulose acetate conventionally used to cellulose acetate propionate, cellulose acetate butyrate, or the like. If cellulose acetate propionate or cellulose acetate butyrate obtained by melt film formation is used instead of the cellulose triacetate film used as a viewing angle compensation film, the effect that the viewing characteristics due to changes in humidity are less likely to fluctuate Is obtained.

Japanese National Patent Publication No. 6-501040 JP 2000-352620 A

  However, when melt film formation is carried out according to the methods described in the examples of these patent documents, the resulting cellulose ester film may be colored or poorly surfaced, or scratched during film winding or processing. Occasionally, optical defects may occur, and care must be taken in managing them.

  In view of the problems of these conventional techniques, an object of the present invention is to provide a cellulose ester film laminate capable of supplying a cellulose ester film having a good surface shape and no scratches. Moreover, an object of this invention is to provide the method of manufacturing such a cellulose-ester film laminated body simply. Another object of the present invention is to provide a polarizing plate, an optical compensation film, and an antireflection film that have good handling properties during processing and excellent optical characteristics. Another object of the present invention is to provide a liquid crystal display device in which a foreign matter failure on a display screen and a change in visibility over time are improved.

These objects have been achieved by the present invention having the following configuration.
[1] A protective film is laminated on at least one surface of a cellulose ester film satisfying the following formulas (S-1) to (S-3) and having a residual solvent amount of 0.01% by mass or less. Cellulose ester film laminate.
Formula (S-1) 2.5 <= A + B <= 3.0
Formula (S-2) 0 ≦ A ≦ 2.2
Formula (S-3) 0.8 ≦ B ≦ 3.0
(In the formula, A represents the substitution degree of the acetyl group to the hydroxyl group of cellulose, and B represents the substitution degree of the acyl group having 3 to 22 carbon atoms to the hydroxyl group of cellulose.)
[2] The cellulose according to [1], wherein the acyl group having 3 to 22 carbon atoms substituted with respect to the hydroxyl group of cellulose in the cellulose ester is at least one of a propionyl group and a butyryl group. Ester film laminate.
[3] The cellulose ester film of [1] or [2], wherein the cellulose ester film contains at least one selected from the group consisting of fine particles, ultraviolet absorbers, plasticizers, and stabilizers. Laminated body.
[4] The cellulose ester film laminate according to any one of [1] to [3], wherein the cellulose ester film is melt-formed using a touch roll.
[5] The protective film comprises a resin base material and an adhesive layer, and the resin base material is selected from the group consisting of polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate and polyimide, polystyrene, polyacrylonitrile, polymethacrylate. [1] to [4], wherein the pressure-sensitive adhesive layer contains at least one selected from the group consisting of an acrylic polymer and an ethylene-vinyl acetate copolymer. The cellulose-ester film laminated body as described in any one.
[6] The front retardation (Re) of the cellulose ester film is 0 to 300 nm, and the retardation (Rth) in the thickness direction is −300 to 700 nm. [1] to [5] ] The cellulose-ester film laminated body as described in any one of.

[7] A step of forming a cellulose ester film by melting a cellulose ester satisfying the following formulas (S-1) to (S-3) at 180 to 230 ° C. and extruding it from a die, and at least the cellulose ester film A method for producing a cellulose ester film laminate, comprising a step of laminating a protective film on one side.
Formula (S-1) 2.5 <= A + B <= 3.0
Formula (S-2) 0 ≦ A ≦ 2.2
Formula (S-3) 0.8 ≦ B ≦ 3.0
(In the formula, A represents the substitution degree of the acetyl group to the hydroxyl group of cellulose, and B represents the substitution degree of the acyl group having 3 to 22 carbon atoms to the hydroxyl group of cellulose.)
[8] The method for producing a cellulose ester film laminate according to [7], wherein melt film formation is performed using a touch roll.
[9] The method for producing a cellulose ester film laminate according to [7] or [8], further comprising a step of saponifying at least one surface of the cellulose ester film.
[10] The method for producing a cellulose ester film laminate according to [9], wherein a step of laminating the protective film is performed after the saponification step.
[11] The method for producing a cellulose ester film laminate according to [10], wherein the protective film is laminated on the saponified surface.

[12] The method for producing a cellulose ester film laminate according to [9], wherein a step of laminating the protective film is performed before the saponification step.
[13] A cellulose ester film laminate produced by the production method according to any one of [8] to [12].

[14] A polarizing plate using a cellulose ester film obtained from the cellulose ester film laminate according to any one of [1] to [6] or [13] as a polarizing film.
[15] An optical compensation film using a cellulose ester film obtained from the cellulose ester film laminate according to any one of [1] to [6] or [13].
[16] An antireflection film using a cellulose ester film obtained from the cellulose ester film laminate according to any one of [1] to [6] or [13].

[17] Using at least one selected from the group consisting of a polarizing plate according to [14], an optical compensation film according to [15], and an antireflection film according to [16], Liquid crystal display device.

  The cellulose ester film laminate of the present invention can easily supply a cellulose ester film having a good surface shape and no scratches by peeling off the protective film. Moreover, according to the manufacturing method of this invention, the damage to the film surface in a process process, etc. can be suppressed significantly, and the cellulose-ester film laminated body which has said characteristic can be provided simply. Furthermore, the polarizing plate, the optical compensation film, and the antireflection film of the present invention are excellent in optical characteristics, and the liquid crystal display device of the present invention suppresses foreign matter failure on the display screen and changes in visibility over time.

  Below, the cellulose-ester film laminated body of this invention, its manufacturing method, etc. are demonstrated in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Cellulose ester]
The cellulose ester used in the present invention satisfies the following formulas (S-1) to (S-3).
Formula (S-1) 2.5 <= A + B <= 3.0
Formula (S-2) 0 ≦ A ≦ 2.2
Formula (S-3) 0.8 ≦ B ≦ 3.0
(In the formula, A represents the substitution degree of the acetyl group to the hydroxyl group of cellulose, and B represents the substitution degree of the acyl group having 3 to 22 carbon atoms to the hydroxyl group of cellulose.)

  The glucose unit which comprises cellulose and has a beta (β) -1,4 bond has free hydroxyl groups at the 2nd, 3rd and 6th positions. The cellulose ester is a polymer (polymer) obtained by esterifying some or all of these hydroxyl groups. The degree of substitution means the total of the ratios of esterification of cellulose for each of the 2nd, 3rd and 6th positions (100% esterification has a degree of substitution of 1). Therefore, the substitution degree is 3 when the hydroxyl groups at the 2-position, 3-position and 6-position are all substituted. In the present invention, A + B is more preferably 2.60 ≦ A + B ≦ 3.0, and further preferably 2.7 ≦ A + B ≦ 3.0. Further, A is preferably 0 ≦ A ≦ 1.8, B is preferably 1.0 ≦ B ≦ 3.0, and more preferably 1.2 ≦ B ≦ 3.0. In the present invention, the substitution degree of the hydroxyl groups at the 2nd, 3rd and 6th positions of the cellulose is not particularly limited, but the substitution degree at the 6th position of the cellulose ester is preferably 0.7 or more, more preferably 0.8. Or more, particularly preferably 0.85 or more, particularly preferably 0.90 or more. Thereby, the solubility and heat resistance of cellulose ester can be improved. The synthesis of a cellulose ester having a high degree of substitution at the 6-position hydroxyl group is described in JP-A-11-5851, JP-A-2002-212338, JP-A-2002-338601, and the like.

  Next, the C3-C22 acyl group represented by the substituent B of the cellulose ester used in the present invention may be either an aliphatic acyl group or an aromatic acyl group. When the acyl group of the cellulose ester used in the present invention is an aliphatic acyl group, the number of carbon atoms is preferably 3-18, more preferably 3-12, and the number of carbons is 3-8. It is particularly preferred that Examples of these aliphatic acyl groups include an alkylcarbonyl group, an alkenylcarbonyl group, and an alkynylcarbonyl group. When the acyl group is an aromatic acyl group, the carbon number is preferably 6-22, more preferably 6-18, and particularly preferably 6-12. Each of these acyl groups may further have a substituent.

  Examples of preferred acyl groups represented by the substituent B include propionyl group, butyryl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group Group, octadecanoyl group, isobutyryl group, pivaloyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthalenecarbonyl group, phthaloyl group, cinnamoyl group and the like. Among these, more preferred are propionyl group, butyryl group, dodecanoyl group, octadecanoyl group, pivaloyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group, and particularly preferred are propionyl group, It is a butyryl group.

  The acyl group constituting the ester of cellulose ester used in the present invention is preferably an aliphatic acyl group having 6 or less carbon atoms, and is selected from the group consisting of an acetyl group, a propionyl group, a butyryl group, a pentanoyl group and a hexanoyl group. The acyl group selected is preferred. More preferred is an acyl group selected from the group consisting of an acetyl group, a propionyl group, a butyryl group and a pentanoyl group, and even more preferred is an acyl group selected from the group consisting of an acetyl group, a propionyl group and a butyryl group. is there. The acyl group which comprises the ester of the cellulose ester used by this invention may be single type, and multiple types may be sufficient as it.

  The raw material cotton and the synthesis method of cellulose ester are described in Invention Technical Disclosure Bulletin (Public Technical No. 2001-1745, published on March 15, 2001, Invention Association), pages 7-12. As the cellulose raw material, those derived from hardwood pulp, softwood pulp and cotton linter are preferably used. As a cellulose raw material, it is preferable to use a high-purity material having an α-cellulose content of 92 mass% to 99.9 mass%. When the cellulose raw material is in the form of a sheet or a lump, it is preferable to pulverize in advance, and it is preferable that the pulverization of the cellulose form proceeds from a fine powder to a feather shape. The water content of the cellulose ester in the present invention is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

  The average degree of polymerization of the cellulose ester preferably used in the present invention is 100 to 700, more preferably 120 to 550, still more preferably 120 to 400, and particularly preferably an average degree of polymerization of 130 to 350.

  In the present invention, only one type of cellulose ester may be used, or two or more types may be mixed and used. Further, the cellulose ester in the present invention may be a mixture of polymer components other than cellulose ester as appropriate. The polymer component to be mixed is preferably one having excellent compatibility with the cellulose ester, and the transmittance when formed into a film is preferably 80% or more, more preferably 90% or more, and further preferably 92% or more.

The cellulose ester used in the present invention preferably has a mass average molecular weight Mw / number average molecular weight Mn ratio of 1.5 to 7.0, particularly preferably 1.5 to 6.0, and more preferably. It is 2.0-5.5, More preferably, it is 2.5-5.5. The cellulose ester is preferably pelletized, and the preferred pellet size is 1 mm ^{3 to} 10 cm ³ , more preferably 5 mm ³ to 5 cm ³ , and even more preferably 10 mm ^{3 to 3} cm ³ . The cellulose ester obtained by drying is preferably stored in a low-temperature dark place in order to be less affected by the environment during storage. Furthermore, it is more preferable to store in a moisture-proof bag made of a moisture-proof material such as aluminum, a SUS drum or a container for storage.

[Additive]
Next, the preferable additive which can be contained in the cellulose-ester film used by this invention is described. In the present invention, various additives such as fine particles, ultraviolet absorbers, plasticizers, (light) stabilizers, and dyes can be used. Below, typical additives are described.

(1) Ultraviolet absorbent In the present invention, it is preferable to add at least one ultraviolet absorbent to the cellulose ester film in order to prevent ultraviolet degradation. By adding an ultraviolet absorber, the light transmittance at a wavelength of 360 nm is preferably 10% or less, more preferably 8% or less, and particularly preferably 5% or less.

  In the present invention, commercially available products may be used as these ultraviolet absorbers. Commercially available benzotriazoles include TINUBIN P (Ciba Specialty Chemicals), TINUBIN234 (Ciba Specialty Chemicals), TINUBIN 320 (Ciba Specialty Chemicals), TINUBIN 326 (Ciba Specialty Chemicals), TINUBIN 327 (Ciba Specialty Chemicals), TINUBIN 328 (Ciba Specialty Chemicals), and Sumisorb 340 (Sumitomo Chemical). Also, as benzophenone ultraviolet absorbers, Seasorb 100 (Cipro Kasei), Seasorb 101 (Cipro Kasei), Seasorb 101S (Cipro Kasei), Seasorb 102 (Cipro Kasei), Seasorb 103 (Cipro Kasei), Adekas Type LA-51 ( Asahi Denka), Chemisorp 111 (Chemipro Kasei), UVINUL D-49 (BASF), etc. Oxalic acid anilide UV absorbers include TINUBIN 312 (Ciba Specialty Chemicals) and TINUBIN 315 (Ciba Specialty Chemicals). In addition, SeaSorb 201 (Cipro Kasei) and Seasorb 202 (Cipro Kasei) are marketed as salicylic acid UV absorbers, and Seasorb 501 (Cipro Kasei) and UVINUL N-539 (BASF) are cyanoacrylate UV absorbers. There is. Examples of the polymeric ultraviolet absorber include the ultraviolet absorbers described in JP-A-2004-148542, [0035] to [0064]. The ultraviolet absorber is preferably used in the range of 0.01 to 10 parts by mass, more preferably in the range of 0.01 to 5 parts by mass, with respect to 100 parts by mass of the cellulose ester. More preferably, it is used in the range of ˜3 parts by mass.

In the present invention, it may be more preferable to use a light stabilizer in combination with the ultraviolet absorber. Along with the ultraviolet absorber, a hindered amine light stabilizer, a hydroxybenzoate light stabilizer, or the like can be preferably used. It is also preferable to use a nickel-based quencher-based stabilizer in combination. The light stabilizer is preferably used in the range of 0.01 to 10 parts by mass, more preferably in the range of 0.01 to 5 parts by mass, with respect to 100 parts by mass of the cellulose ester. More preferably, it is used in the range of ˜3 parts by mass.
(2) Plasticizer By adding a plasticizer to the cellulose ester, the crystal melting temperature (Tm) of the cellulose ester can be lowered. The molecular weight of the plasticizer used in the present invention is not particularly limited, and may be a low molecular weight or a high molecular weight. Examples of the plasticizer include phosphate esters, alkylphthalylalkyl glycolates, carboxylic acid esters, and fatty acid esters of polyhydric alcohols. These plasticizers may be solid or oily. That is, the melting point and boiling point are not particularly limited. When performing melt film formation, those having non-volatility can be particularly preferably used. The plasticizer is preferably used in the range of 0.1 to 15 parts by mass, more preferably in the range of 0.5 to 13 parts by mass, with respect to 100 parts by mass of the cellulose ester, and 3 to 12 parts by mass. More preferably, it is used within the range of parts.

(3) Stabilizer In the present invention, a phosphite compound, a phosphite compound, a phosphor as a stabilizer for preventing thermal deterioration and preventing coloring as required within the range not impairing the required performance. Fate, thiophosphate, weak organic acid, epoxy compound or the like may be added alone or in admixture of two or more. As specific examples of the phosphite stabilizer, compounds described in paragraphs [0023] to [0039] of JP-A No. 2004-182979 can be more preferably used. Specific examples of the phosphite ester stabilizer include JP-A No. 51-70316, JP-A No. 10-306175, JP-A No. 57-78431, JP-A No. 54-157159, and JP-A No. 54-157159. The compounds described in JP-A-55-13765 can be used.

  Moreover, it is also preferable to add a deterioration inhibitor and an antioxidant to the cellulose ester used in the present invention. By adding a phenol compound, a thioether compound, a phosphorus compound or the like as a deterioration inhibitor or an antioxidant, a synergistic effect appears in deterioration and oxidation prevention. Furthermore, as other stabilizers, the materials described in detail on pages 17 to 22 of the Japan Institute of Invention Disclosure Bulletin (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention) are preferably used. Can do. These various additives are preferably used in the range of 0.01 to 10 parts by weight, more preferably in the range of 0.01 to 5 parts by weight, based on 100 parts by weight of the cellulose ester. More preferably, it is used in the range of 0.05 to 3 parts by mass.

(4) Optical adjusting agent An optical adjusting agent can also be added to the cellulose ester used in the present invention. For example, a retardation control agent for controlling optical anisotropy is optionally added. In order to adjust the retardation of the cellulose ester film, it is preferable to use an aromatic compound having at least two aromatic rings as a retardation control agent. The aromatic compound is preferably used in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the cellulose ester. The aromatic compound is more preferably used in the range of 0.05 to 15 parts by mass and more preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the cellulose ester. In the present invention, two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring.

(5) Polymer having a fluorine atom-release agent The cellulose ester in the present invention preferably contains a polymer having a fluorine atom. The polymer having a fluorine atom can exhibit an action as a release agent. As a polymer which has a fluorine atom, the polymer of Unexamined-Japanese-Patent No. 2001-269564 can be mentioned, for example. A polymer having a fluorine atom is preferably a polymer obtained by polymerizing a monomer containing a fluorinated alkyl group-containing ethylenically unsaturated monomer as an essential component. The addition amount is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of the cellulose ester, and 0.05 More preferably, it is used in the range of ˜2 parts by mass.

(6) Dye In the present invention, it is preferable to add a blue dye in order to suppress yellowing of the film and prevent oxidation of the film. These dyes are also additives having the same effect as the plasticizer. Preferred examples of the dye include anthraquinone dyes. The anthraquinone dye can have an arbitrary substituent at positions 1 to 8 of the anthraquinone. Preferable substituents include an anilino group, a hydroxyl group, an amino group, and a nitro group that may be substituted. The addition amount is preferably in the range of 0.000005 to 1 part by weight, more preferably in the range of 0.00005 to 1.5 parts by weight, with respect to 100 parts by weight of the cellulose ester. More preferably, it is in the range of -0.5 parts by mass.

  Specific examples of the anthraquinone dye are shown below, but the anthraquinone dye that can be used in the present invention is not limited thereto. 1,4-diphenylaminoanthraquinone, 1,4-bis (2,4,6-trimethylphenyl) anthraquinone, 1,4-bis (2,4-diethyl-4-methylphenyl) anthraquinone, , 4-bis (2,6-dimethyl-4-cyclohexylsulfonamidophenyl) anthraquinone, 1-methoxyphenylamino-4-hydroxy-5-methoxyphenylamino-8-hydroxyanthraquinone, 1,4-bis (2 , 4,6-Tripropylcyclohexylsulfonamidophenyl) anthraquinone, 1-ethoxyphenylamino-4-hydroxy-5-methoxyphenylamino-8-hydroxyanthraquinone, 1,4-bis (2,4,6-tri Methoxyphenylamino) anthraquinone, 1,4-bis (2,4,6-tri Tilphenyl) anthraquinone, 1,4-bis (2,4-diisopropoxy-6-methylphenyl) anthraquinone, 1,4-bis (2,6-dichloro-4-cyclohexylsulfonamidophenyl) anthraquinone, 1 -(2,4,6-trimethoxyphenylamino) -4-hydroxy-5- (2,4,6-trimethoxyphenylamino) -8-hydroxyanthraquinone, 1,4-bis (2,4,6 -Tripropylcyclohexylsulfonamidophenyl) anthraquinone, 1,5-bis (methoxyphenylamino) -4,8-dihydroxyanthraquinone and the like can be mentioned.

[Melting process]
The cellulose ester film that is the substrate of the cellulose ester film laminate of the present invention is preferably produced by a melt film forming method. In general, the melt film-forming method preheats cellulose ester to a predetermined temperature in advance, and mixes and mixes additives, etc., through a kneading and extrusion process, a casting process, a stretching process, a relaxing process, a cooling process, a winding process, and a processing process. A desired cellulose ester film is obtained. The optimization of melt film forming conditions is described in detail below.

(Pelletized)
In the present invention, the cellulose ester and the additive are preferably pelletized prior to melt film formation. It is preferable to dry the cellulose ester in advance for pelletization. Moreover, when pelletizing, the said additive can also be injected | thrown-in from the raw material input port and vent port in the middle of an extruder. The extrusion residence time in pelletization is 10 seconds to 60 minutes, more preferably 15 seconds to 30 minutes. If sufficient melting is possible, a shorter residence time is preferable in terms of suppressing resin deterioration and yellowing.

(Melting film formation)
(1) Drying In the present invention, it is preferable to use those pelletized by the above-mentioned method, and the moisture content in the pellets is preferably 1% or less, more preferably 0.5% or less, even more preferably, prior to melt film formation. Is 0.01% or less, and then charged into a hopper of a melt extruder. At this time, the hopper is preferably 20 ° C to 110 ° C, more preferably 40 ° C to 100 ° C, and further preferably 50 ° C to 90 ° C. At this time, the hopper is preferably dehumidified air or the like and has a constant air volume and temperature. Further, it is more preferable that the inside of the hopper has a vacuum sealed structure and an inert gas such as nitrogen is enclosed.

(2) Melt extrusion The above-mentioned cellulose ester is supplied into the cylinder through the supply port of the extruder. The inside of the cylinder is composed of a supply unit that quantitatively transports the cellulose ester supplied from the supply port in order from the supply port side, a compression unit that melt-kneads and compresses the cellulose ester, and a weighing unit that measures the melt-kneaded and compressed cellulose ester. Is done. Further, it is more preferable that the inside of the extruder is carried out in an inert (nitrogen or the like) air stream or while being evacuated using a vented extruder. The screw compression ratio of the extruder is preferably set to 2.5 to 4.5, and L / D is preferably set to 20 to 70.

  In the production method of the present invention, the extrusion temperature is 180 ° C to 230 ° C, preferably 190 ° C to 230 ° C, more preferably 195 ° C to 230 ° C. The temperature at this time shows the temperature of the most downstream part of an extruder. In general, single-screw extruders with relatively low equipment costs are often used as the types of extruders, and there are screw types such as full flight, madok and dalmage, but cellulose esters with relatively poor thermal stability. The resin is preferably a full flight type. Biaxial extruders can be broadly classified into two types: the same direction and different directions, and both types can be used.

(3) Casting By the above method, the molten resin extruded from the die onto the sheet is cooled and solidified on a casting drum to obtain a film. At this time, it is preferable to use a method such as an electrostatic application method, an air knife method, an air chamber method, a vacuum nozzle method, or a touch roll method to increase the adhesion between the casting drum and the melt-extruded sheet. Such an adhesion improving method may be performed on the entire surface of the melt-extruded sheet or a part thereof. In particular, a method called “edge pinning”, in which only both ends of the film are brought into close contact with each other, is often used, but the method is not limited to this. The method of using a plurality of casting drums and slowly cooling them is more preferable. In particular, it is relatively common to use three cooling rolls, but this is not restrictive. The diameter of the roll is preferably 50 mm to 5000 mm, more preferably 100 mm to 2000 mm, and still more preferably 150 mm to 1000 mm. The interval between the plurality of rolls is preferably 0.3 mm to 300 mm, more preferably 1 mm to 100 mm, and still more preferably 3 mm to 30 mm. The temperature of the casting drum is preferably 60 ° C to 160 ° C, more preferably 70 ° C to 150 ° C, still more preferably 80 ° C to 140 ° C. Then, it peels off from a casting drum, winds up after passing through a nip roll. The winding speed is preferably 10 m / min to 100 m / min, more preferably 15 m / min to 80 m / min, still more preferably 20 m / min to 70 m / min. The film forming width is preferably 0.7 m to 5 m, more preferably 1 m to 4 m, and still more preferably 1.3 m to 3 m. When the so-called touch roll method is used, the surface of the touch roll may be a resin such as rubber or Teflon (registered trademark), or a metal roll. Further, it is possible to use a roll called a flexible roll because the roll surface is slightly dented by the pressure when touched by reducing the thickness of the metal roll, and the crimping area is widened.

Furthermore, touch roll film formation is described in detail below. In the present invention, as described above, it is more preferable to form a film using a touch roll on a casting drum after extrusion from a die after melting. In this method, the melt discharged from the die is sandwiched between a casting drum and a touch roll to be cooled and solidified. By using this, the fine unevenness formed on the above-described film can be smoothed, and blurring in the liquid crystal display device can be reduced.
Such a touch roll preferably has elasticity in order to reduce residual strain generated when the melt from the die is sandwiched between the rolls. In order to give elasticity to the roll, it is necessary to make the outer cylinder thickness of the roll thinner than a normal roll, and the outer wall thickness Z is preferably 0.05 mm to 7.0 mm, more preferably 0.2 mm to 5.0 mm. More preferably, it is 0.3 mm-2.0 mm. For example, by reducing the thickness of the outer cylinder, an elastic body layer is provided on a metal shaft or an elastic body layer, and the outer cylinder is placed on the elastic body layer, and a liquid medium layer is provided between the elastic body layer and the outer cylinder. The thing which enabled the touch roll film formation by the ultra-thin outer cylinder by satisfy | filling is mentioned. The casting roll and the touch roll preferably have a mirror surface, and the arithmetic average height Ra is 100 nm or less, preferably 50 nm or less, more preferably 25 nm or less. Specifically, for example, JP-A-11-314263, JP-A-2002-36332, JP-A-11-235747, JP-A-2004-216717, JP-A-2003-145609, and International Publication No. 97/28950 pamphlet. The one described in can be used.

  Thus, since the touch roll is filled with the fluid inside the thin outer cylinder, when the touch roll is brought into contact with the casting roll, it is elastically deformed into a concave shape by the pressing. Therefore, since the touch roll and the casting roll are in surface contact with the cooling roll, the pressure is dispersed and a low surface pressure can be achieved. For this reason, the fine unevenness | corrugation of the surface can be corrected, without leaving a residual distortion in the film pinched | interposed between these. The linear pressure of the preferred touch roll is 3 kg / cm to 100 kg / cm, more preferably 5 kg / cm to 80 kg / cm, and still more preferably 7 kg / cm to 60 kg / cm. The linear pressure referred to here is a value obtained by dividing the force applied to the touch roll by the width of the discharge port of the die. If the linear pressure is 3 kg / cm or more, the effect of reducing fine irregularities by pressing the touch roll is likely to be obtained. On the other hand, if it is 100 kg / cm or less, the touch roll is hardly distorted, and it is easy to reduce the fine irregularities over the entire width by uniformly touching the entire casting roll. The touch roll is preferably set to 60 ° C to 160 ° C, more preferably 70 ° C to 150 ° C, and still more preferably 80 ° C to 140 ° C. Such temperature control can be achieved by passing a temperature-controlled liquid or gas through these rolls.

[Stretching process]
It is also preferred that the cellulose ester film formed into a film in the melt film-forming process is stretched as it is in a continuous stretching process or after being rolled up once. Stretching may not be performed. The stretching is preferably performed at Tg to (Tg + 50 ° C.), more preferably (Tg + 1 ° C.) to (Tg + 30 ° C.), and further preferably (Tg + 2 ° C.) to (Tg + 20 ° C.). The preferred draw ratio is preferably -10% to 50% in at least one direction. The draw ratio is more preferably -5% to 50%, further preferably -3% to 45%, particularly preferably 0% to 40%. These stretching operations may be performed in one stage or in multiple stages. The draw ratio here is determined using the following equation.
Stretching ratio (%) = 100 × {(length after stretching) − (length before stretching)} / length before stretching Such stretching is performed by using two or more pairs of nip rolls with increased peripheral speed on the outlet side. The film may be stretched in the longitudinal direction (longitudinal stretching), or both ends of the film may be held by a chuck and spread in the orthogonal direction (longitudinal direction and perpendicular direction) (lateral stretching). Moreover, you may relax after extending | stretching.

[Take-up]
The sheet thus obtained is preferably trimmed at both ends and wound up. After trimming, the trimmed part is recycled as a film raw material of the same type or as a film raw material of a different type after being subjected to a granulation process or a depolymerization / repolymerization process as necessary. May be used. Any type of trimming cutter such as a rotary cutter, shear blade or knife may be used.
As for the material, either carbon steel or stainless steel may be used. In general, it is preferable to use a cemented carbide blade or a ceramic blade because the life of the blade is long and the generation of chips is suppressed. In addition, although knurling (thickening) processing may be given to both ends after trimming, it is not always necessary. The thickness of the cellulose ester film thus obtained is preferably 20 μm to 400 μm, more preferably 40 μm to 200 μm, and particularly preferably 50 μm to 150 μm. In this invention, when the thickness of the obtained cellulose-ester film exceeds 200 micrometers, it can be set as the preferable film thickness of this invention by extending | stretching further.

[surface treatment]
The cellulose ester film used in the present invention may be surface treated. By performing the surface treatment, for example, the adhesion between the cellulose ester film and each functional layer (for example, the undercoat layer and the back layer) can be improved. As the surface treatment, for example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here refers to so-called low-temperature plasma that occurs under a low pressure gas of 10 ^{−3 to} 20 Torr (about 0.13 to 2666 Pa), but may be a glow discharge treatment under atmospheric pressure.

[Saponification process]
The cellulose ester film used in the present invention may be saponified. The cellulose ester film used in the present invention may be subjected to a surface treatment such as an electron beam before or after the saponification treatment. For example, glow discharge treatment (atmospheric pressure or vacuum system), ultraviolet irradiation treatment, and corona treatment can be used. When cellulose ester is used as a protective film for a polarizing film, it is generally performed to saponify with an alkaline aqueous solution, apply polyvinyl alcohol as an adhesive, and bond the polarizing film together. At this time, since the saponified cellulose ester easily adheres to the film surfaces, it was difficult to wind and store the saponified cellulose ester. For this reason, it has been common to incorporate a saponification treatment step into the step of producing a polarizing plate, which has been limited in productivity in producing the polarizing plate. According to the present invention, the saponification process can be incorporated into the production process of the cellulose ester film laminate without being restricted by such productivity. For this reason, according to the present invention, it is possible to produce a polarizing plate quickly and easily using a cellulose ester that has been saponified in advance.

(Alkaline saponification solution)
Next, the alkali saponification process will be described. An alkaline saponification aqueous solution is used in the alkali saponification treatment step. As the alkali agent in the alkali saponification aqueous solution, either an inorganic alkali agent or an organic alkali agent can be used, and it is not particularly limited as long as it has alkali saponification characteristics. Examples of strong inorganic alkali agents include alkali metal hydroxides (for example, NaOH, KOH, LiOH), Group 2 metal hydroxides, tribasic sodium phosphate, tribasic potassium, trivalent ammonium, dibasic sodium phosphate, Potassium, ammonium, sodium borate, potassium and ammonium are preferred.
Examples of the organic alkali agent include ammonium hydroxide, amines (for example, monomethylamine, dimethylamine, trimethylamine, diethanolamine, ethyleneimine, triethylamine), and free bases of complex salts (for example, [Pt (NH ₃ ) ₆ ] (OH) ₄ ) is preferred. Among these, NaOH, KOH, and LiOH, which are alkali metal hydroxides, are more preferable to cause a saponification reaction at a low concentration, and NaOH and KOH are particularly preferable. These alkali agents can be used alone or in combination of two or more.

  The concentration of the alkaline agent in the alkaline saponification aqueous solution is determined according to the type of alkaline agent used, the reaction temperature and the reaction time. In order to complete the saponification reaction in a short time, it is preferable to prepare a solution at a high concentration. However, when the alkali concentration is too high, the stability of the alkali saponification aqueous solution is impaired, and in some cases, it may be deposited in the liquid or gas-liquid interface as a solid content during long-time application. The concentration of the alkali saponification aqueous solution is preferably 0.21 to 5 mol / L, more preferably 0.5 to 5 mol / L, and most preferably 0.5 to 3 mol / L.

(Surfactant)
In some cases, the surfactant used in the alkaline saponification aqueous solution can reduce the surface tension of the alkaline saponification aqueous solution to facilitate coating, prevent cissing failure, The reaction product can be stably present in the alkaline saponification aqueous solution, and precipitation and solidification can be prevented in the subsequent water washing step. The concentration of the surfactant is preferably 0.005 to 15% by mass, and more preferably 0.02 to 1% by mass.

  The surfactant preferably used in the alkali saponification method in the present invention is not particularly limited as long as it can be dissolved or dispersed in the alkali saponification solution. Any of nonionic surfactants (nonionic surfactants, fluorosurfactants), ionic surfactants (anions, cations, amphoteric surfactants) can be suitably used. Among the surfactants, nonionic surfactants and anionic surfactants are preferably used from the viewpoints of solubility and saponification performance. These surfactants may be added alone or in combination of one or more different ionic surfactants or nonionic surfactants. A nonionic surfactant may be added in combination.

Hereinafter, the surfactants that can be used in the present invention will be sequentially described.
(Anionic surfactant)
Examples of the anionic surfactant include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid ester salts, α-olefin sulfonic acid salts, linear alkyl benzene sulfonic acid salts, branched chain. Alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, disodium N-alkylsulfosuccinate monoamide Salts, petroleum sulfonates, sulfated beef tallow oil, sulfates of fatty acid alkyl esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fats Monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates Preferable examples include salts, partially saponified products of styrene / maleic anhydride copolymer, partially saponified products of olefin / maleic anhydride copolymer, and naphthalene sulfonate formalin condensates.

(Cationic surfactant)
Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts such as tetrabutylammonium bromide, polyoxyethylene alkylamine salts, polyethylene polyamine derivatives, and the like.

(Amphoteric surfactant)
Examples of amphoteric surfactants include carboxybetaines, alkylaminocarboxylic acids, sulfobetaines, aminosulfuric acid esters, imidazolines, and the like.
(Nonionic surfactant)
Nonionic surfactants include, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, Sorbitan fatty acid partial esters, pentaerythritol fatty acid (12), partial esters described in JP-A-2004-203964, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, Polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, polyoxyethylenated castor oil, Polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides and the like.

  Specific examples thereof include, for example, polyethylene glycol, polyoxyethylene lauryl ether, polyoxyethylene nonyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene behenyl ether, polyoxyethylene Oxyethylene polyoxypropylene cetyl ether, polyoxyethylene polyoxypropylene behenyl ether, polyoxyethylene phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene stearamide, polyoxy Ethylene oleamide, polyoxyethylene castor oil, polyoxyethylene ethylene abietic Ether, polyoxyethylene nonine ether, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene glyceryl monooleate, polyoxyethylene glyceryl monostearate, polyoxyethylene propylene glycol monostearate, oxyethyleneoxy Propylene block polymer, distyrenated phenol polyethylene oxide adduct, tribenzylphenol polyethylene oxide adduct, octylphenol polyoxyethylene polyoxypropylene adduct, glycerol monostearate, sorbitan monolaurate, polyoxyethylene sorbitan monolaurate, etc. It is done. These nonionic surfactants preferably have a mass average molecular weight of 300 to 50,000, more preferably 500 to 5,000.

(4) Fluorosurfactant A fluorosurfactant refers to a surfactant containing a perfluoroalkyl group in the molecule. Examples of such a fluorosurfactant include an anionic type such as perfluoroalkyl carboxylate and perfluoroalkyl phosphate, an amphoteric type such as perfluoroalkyl betaine, and a cationic type such as perfluoroalkyltrimethylammonium salt. , Perfluoroalkylamine oxide, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl group and hydrophilic group-containing oligomer, perfluoroalkyl group and lipophilic group-containing oligomer, perfluoroalkyl group, hydrophilic group and lipophilic group-containing oligomer And nonionic types such as perfluoroalkyl group and lipophilic group-containing urethane.
Among the above surfactants, those having “polyoxyethylene” can be read as polyoxyalkylenes such as polyoxymethylene, polyoxypropylene and polyoxybutylene, and these are also included in the surfactant. The The surfactants may be used alone or in combination of two or more as long as the effect is not impaired by the combined use.

  In addition, concentrated alkali agents, fatty acid salts, and films can be obtained by adjusting the chloride chloride ion (preferably chloride ion) and the polyvalent metal ions such as calcium ion and magnesium ion in the alkaline saponification aqueous solution to 1000 mg / L or less, respectively. It becomes possible not to deposit extract substances, such as an additive substance, on the film surface. The main solvent of the alkaline saponification aqueous solution is water, but the water used is preferably pure water. The calcium concentration in pure water is preferably 0.001 to 100 mg / L, more preferably 0.001 to 50 mg / L, and particularly preferably 0.001 to 10 mg / L. The magnesium concentration is preferably 0.001 to 50 mg / L, more preferably 0.001 to 30 mg / L, and particularly preferably 0.001 to 10 mg / L.

  Polyvalent metal ions other than calcium and magnesium, such as Be, Sr, Ba, Al, Sn, Pb, Ti, Cr, Mn, Fe, Co, Ni, Ni, Cu (II), Co, and Zn are not included. It is preferable. The concentration of the polyvalent metal ion is preferably 0.002 to 150 mg / L. On the other hand, it is preferable that the alkali saponification solution does not contain anions such as chloride ions and carbonate ions. The chloride ion concentration is preferably 0.001 to 100 mg / L, more preferably 0.001 to 50 mg / L, and particularly preferably 0.001 to 10 mg / L. Moreover, it is preferable that carbonate ions are not included. The carbonate ion concentration is preferably 0.001 to 500 mg / L, more preferably 0.001 to 100 mg / L, and particularly preferably 0.001 to 20 mg / L. The concentration of each of the above ionic species is preferably as low as possible. The lower limit of 0.001 mg / L means that it is below the measurement limit. In these concentration ranges, generation of insoluble matter in the solution is suppressed. In these concentration ranges, generation of insoluble matter in the solution is suppressed.

  The surface tension of the alkaline saponification aqueous solution used in the present invention is preferably 15 to 65 mN / m. More preferably, it is 15-60 mN / m, Most preferably, it is 15-50 mN / m. The viscosity of the alkaline saponification aqueous solution used in the present invention is preferably 0.6 to 20 mPa · s, more preferably 1 to 15 mPa · s. The surface tension of the alkali saponification aqueous solution is preferably as described above. Within this range, the wettability to the film surface, the retention of the solution applied to the film surface, the alkali liquid from the film surface after the saponification treatment Removability is sufficiently performed, and a stable coating operation can be realized.

The density of the alkali saponification solution is preferably 0.9~1.4g / cm ^3, more preferably 0.95~1.3g / cm ^3, 1.0~1.2g / Particularly preferred is cm ³ . If the density of the aqueous alkali saponification solution is too low, wind unevenness due to wind pressure due to conveyance may occur, and the uniformity of processing may be impaired. On the other hand, if the density of the aqueous alkali saponification solution is too high, a coating streak parallel to the transport direction is generated due to its own weight, which also impairs processing uniformity and may cause uneven thickness of the alignment film. Further, the specific conductivity of the alkali saponification aqueous solution of the alkali saponification method is preferably 20 mS / cm to 2 S / cm in order to minimize the load in the washing step described later, and 50 mS / cm to 1.5 S / cm. It is more preferable that it is 100 mS / cm-1 S / cm. By setting the specific conductivity to 2 S / cm or less, a salt that causes a bright spot failure (foreign matter defect) is less likely to occur, and poor adhesion of the optical compensation layer is less likely to occur.

  Further, as the liquid property of the alkali saponification aqueous solution, the absorbance of the liquid at a measurement wavelength of 400 nm is preferably less than 2.0. When a liquid having a high absorbance is used, a reaction product with the cellulose ester film and a film additive dissolved in the liquid adhere to the cellulose ester film and cause a bright spot failure (foreign substance defect). For controlling the absorbance of the alkaline saponified aqueous solution, activated carbon can be used to adsorb and remove the eluted components. Activated carbon is sufficient if it has a function of removing colored components in the saponification solution, and there is no limitation on the form, material, and the like. The method employed may be a method of directly putting activated carbon into an alkaline saponification aqueous solution tank, or a method of circulating a saponification aqueous solution between a saponification aqueous solution tank and a purifier filled with activated carbon.

  The alkali coating amount required for the saponification reaction is the total number of saponification sites obtained by multiplying the number of saponification reaction sites per unit area of the cellulose ester film by the saponification depth necessary to develop adhesion with the alignment film (= theoretical alkali coating) Amount) is a guide. As the saponification reaction proceeds, the alkali is consumed and the reaction rate decreases, so it is actually preferable to apply several times the theoretical alkali coating amount. Specifically, it is preferably 2 to 20 times the theoretical alkali coating amount, and more preferably 2 to 5 times.

(Defoamer)
An antifoaming agent may be added to the alkali saponification aqueous solution and the alkali dilution solution. The additive can be contained in the alkaline saponification aqueous solution at a concentration of preferably 0.0051 to 15% by mass, and more preferably 0.005 to 3% by mass. On the other hand, the alkali diluted solution can contain 0.001 to 2% by mass, particularly preferably 0.005 to 0.5% by mass. Within this range, fine bubbles do not adhere to the film surface, and the saponification by the alkali treatment proceeds uniformly without unevenness.

  Antifoaming agents include oils and fats such as castor oil and linseed oil, fatty acids such as stearic acid and oleic acid, fatty acid esters such as natural wax, alcohols such as polyoxyalkylene monohydric alcohol, di-tert- Amylphenoxyethanol, heptylcellosolve, nonylcellosolve, ethers such as 3-heptylcarbitol, phosphate esters such as tributylphosphate and tris (butoxyethyl) phosphate, amines such as diamylamine, polyalkyleneamide, acylate polyamide, etc. Metal soaps such as amides, aluminum stearate, calcium stearate, potassium oleate, calcium wool oleate, sulfates such as sodium lauryl sulfate, dimethylpolysiloxane, methylphenol Silicone oils such as nylpolysiloxane, methylhydrogen polysiloxane, fluoropolysiloxane, dimethylpolysiloxane and polyalkylene oxide copolymer, and silicone-based antifoaming agents such as solution type, emulsion type, paste type silicone oil, etc. Is mentioned.

An organic solvent other than the organic solvents described above can be added to the alkaline saponification aqueous solution used in the present invention as a solubilizing agent for the surfactant and antifoaming agent in the alkaline saponification aqueous solution. There is no particular limitation as long as it is preferably a solvent having solubility in water. For example, methanol, ethanol, n-propanol, isopropanol, butanol, ethylene glycol, diethylene glycol, ethoxyethanol, butoxyethanol, diethylene glycol monoethyl ether, ethylene glycol monobutyl ether, benzyl alcohol, fluorinated alcohol (for example, C _n F _{2n + 1} (CH ₂ ) _k OH (n is an integer of 3 to 8, k is an integer of 1 or 2), 1,1,1,2,2,3,3-heptafluoropropanol, hexafluorobutanediol, Perfluorocyclohexanol, etc.). The content of these organic solvents is preferably 0.1 to 5% by mass with respect to the total mass of the liquid used.

(Antidepressant / Antimicrobial agent)
An antifungal agent and / or a fungicide may be further added to the alkaline saponification aqueous solution used in the present invention. The antifungal agent and antibacterial agent used in the present invention may be anything as long as they do not adversely affect alkali saponification. Specifically, thiazolylbenzimidazole compounds, isothiazolone compounds, chlorophenol compounds , Bromophenol compounds, thiocyanic acid and isothiocyanic acid compounds, acid azide compounds, diazines and triazine compounds, thiourea compounds, alkylguanidine compounds, quaternary ammonium salts, organic tin and organic zinc compounds, cyclohexylphenol compounds , Imidazole and benzimidazole compounds, sulfamide compounds, active halogen compounds such as chlorinated sodium isocyanurate, chelating agents, sulfites, and various antibacterial and antifungal agents such as antibiotics represented by penicillin .

  Others E. West, "" Water Quality Criteria "" Phot. Sci. and Eng. , Vol9 No. 6 (1965), various antifungal agents described in JP-A-57-8542, 58-105145, 59-126533, 55-111942, and 57-157244, The use of compounds such as those described in “History of antibacterial and antifungal” by Hiroshi Horiguchi, Sankyo Publishing (Sho 57), “Handbook of Antibacterial and Antifungal Technology”, Japanese Society of Antibacterial and Antifungal Society, Gihodo (Sho 61) Can do. The addition amount of the antifungal agent and / or the antibacterial agent is preferably 0.01 to 50 g / L, more preferably 0.05 to 20 g / L in the alkaline saponification aqueous solution.

  An organic solvent can be optionally added to the alkaline saponification aqueous solution used in the present invention. There is no particular limitation as long as it is a solvent having solubility in water. For example, methanol, ethanol, n-propanol, isopropanol, butanol, ethylene glycol, diethylene glycol, ethoxyethanol, butoxyethanol, diethylene glycol monoethyl ether, ethylene glycol monobutyl ether, benzyl alcohol, 3-phenyl-1-propanol, 4 -Phenyl-1-butanol, 4-phenyl-2-butanol, 2-phenyl-1-butanol, 2-phenoxyethanol, 2-benzyloxyethanol, o-methoxybenzyl alcohol, m-methoxybenzyl alcohol, p-methoxybenzyl alcohol Benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-methylcyclohexanol, Alcohols (e.g. 1,1,1,2,2,3,3 hepta fluoroalkyl propanol, hexafluoro-butanediol, perfluoro cyclohexanol), and the like. The content of the organic solvent is preferably 0.1 to 5% by mass with respect to the total mass of the liquid used. The amount used is closely related to the amount of surfactant used, and it is preferable to increase the amount of surfactant as the amount of organic solvent increases. This is because the amount of the surfactant is small, and if the amount of the organic solvent is large, the organic solvent is not completely dissolved, so that it is impossible to expect a good saponification treatment.

  The alkaline saponification aqueous solution used in the present invention preferably contains at least one compound selected from non-reducing sugars because it has a pH buffering action in combination with an alkaline agent. Such non-reducing sugars are saccharides that do not have a free aldehyde group or ketone group and do not exhibit reducing properties, and are trehalose-type oligosaccharides in which reducing groups are bonded to each other, and glycosides in which a reducing group of saccharides and non-saccharides are bonded. These are classified into sugar alcohols reduced by hydrogenation of the body and saccharides, both of which are preferably used in the present invention. Trehalose type oligosaccharides include saccharose and trehalose. Examples of glycosides include alkyl glycosides, phenol glycosides, mustard oil glycosides, and the like. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, durisit and allozulcit. In addition, multibits obtained by hydrogenation of disaccharides and reduced forms (reduced candy) obtained by hydrogenation of oligosaccharides are preferably used. Among these, preferred non-reducing sugars for the present invention are sugar alcohol and saccharose. Particularly, D-sorbite, saccharose, and reduced starch syrup are preferable because they have a buffering action in an appropriate pH region and are inexpensive. These non-reducing sugars can be used alone or in combination of two or more thereof, and the proportion of the non-reducing sugar in the developer is preferably from 0.1 to 30% by mass, and more preferably from 1 to 20% by mass.

(Other additives to alkali saponification solution)
In addition, you may use another additive together for the alkali saponification liquid used by this invention. For example, alkaline solution stabilizers (antioxidants etc.), known pH buffering agents and the like can be mentioned. In the present invention, the additive of the alkaline saponification aqueous solution is not limited to these. The temperature of the alkali saponification aqueous solution is desirably equal to the reaction temperature (= temperature of the cellulose ester film). In order to perform stable coating, the temperature needs to be lower than the boiling point of water, preferably 15 ° C. to 90 ° C., more preferably 15 to 80 ° C., particularly 25 to 25 ° C. It is preferable that it is 70 degreeC.

(Alkaline saponification method)
The surface treatment method of the cellulose ester film used in the present invention is a step of saponifying the surface of the cellulose ester film using an alkaline saponified aqueous solution at a temperature above room temperature using the alkaline saponified aqueous solution, and the alkaline saponified aqueous solution from the cellulose ester film. The alkali saponification treatment is preferably carried out by a washing step, a step of neutralizing the alkaline aqueous solution with an acidic aqueous solution, and a step of washing with water. For the step of treating the cellulose ester film with the aqueous alkali saponification solution, any conventionally known method may be used, and examples thereof include a dipping method, a spraying method, and a coating method.

  A method of immersing a cellulose ester film in a saponification solution bath that is generally performed will be described. The size of the treatment bath is not particularly limited as long as it is a container capable of a predetermined temperature and treatment time. As the arrangement of the treatment process, the process arrangement of a sending-out part- (electron beam treatment part) -alkali saponification treatment tank-water washing tank-acid neutralization tank-water washing tank-drying process part-winding part is common. The temperature of each tank is not particularly limited as long as it is controlled at 5 to 90 ° C. and a processing time of 5 to 1200 seconds. The saponification bath is more preferably 15 to 80 ° C, particularly preferably 25 to 70 ° C. Further, the treatment time is more preferably 10 seconds to 600 seconds, and particularly preferably 10 to 300 seconds. Moreover, as an acidic neutralization tank, it is more preferable that it is 5-80 degreeC, and it is especially preferable that it is 10-50 degreeC. Further, the treatment time is more preferably 10 seconds to 600 seconds, and particularly preferably 10 to 300 seconds. About a water-washing tank, it is more preferable that it is 5-80 degreeC, and it is especially preferable that it is 10-50 degreeC. Further, the treatment time is more preferably 10 seconds to 600 seconds, and particularly preferably 10 to 300 seconds.

  Moreover, 25-150 degreeC is preferable, as for the temperature of a drying process, 30-140 degreeC is more preferable, Especially 40-130 degreeC is further more preferable. The drying time is preferably 5 to 1500 seconds, more preferably 20 to 1200 seconds, and particularly preferably 60 to 1200 seconds. The processing method may be conveyed in a roll shape or may be processed in a sheet shape. In the case of a roll-like cellulose ester film, it may be handled consistently from sending out to drying, or it may be cut at any point in the process and further handled in a roll state of a certain length. However, a post-processing step may be performed in the sheet state. As a conveyance speed, 1-200 m / min is preferable, More preferably, 3-150 m / min is more preferable, Furthermore, 10-150 m / min is further more preferable.

In the process of applying alkali saponification aqueous solution to cellulose ester film, die coater (extrusion coater, slide coater), roll coater (forward roll coater, reverse roll coater, gravure coater), rod coater (rod with thin metal wire wound around it) ) Can be preferably used. The coating method is described in various documents (for example, Modern Coating and Drying Technology, Edward Cohen and Edgar B. Gutoff, Edits., VCH Publishers, Inc, 1992). The coating amount of the alkali saponification solution is then, taking into account the waste treatment to water washing removed as much as possible it is desirable to suppress, preferably ^{1~100ml / m 2, 1~50ml / m} 2 is more preferable. A rod coater, gravure coater, and blade coater that can be stably operated even in a small coating amount range are particularly preferred. Further, it is preferable to apply the alkaline saponification aqueous solution to the lower surface of the cellulose ester film in order to easily wash off the alkaline saponification aqueous solution from the cellulose ester film after applying the alkaline saponification aqueous solution and saponifying the cellulose ester film. The variation in the amount of water sprayed per unit time is preferably controlled to be less than 30% in both the longitudinal direction and the width direction of the cellulose ester film being conveyed. Moreover, a continuous application method can also be adopted.

  When using the coating-type alkaline saponification method, it is recommended to keep the temperature of the electron beam-treated cellulose ester film at room temperature (20 ° C.) or higher until the saponification reaction is completed after applying the alkaline saponification aqueous solution. The heating means is selected in consideration of the fact that one side of the cellulose ester film is wet with the alkaline saponification aqueous solution. Hot air collision (spraying) on the opposite surface of the coating, contact heat transfer with a heating roll, induction heating with a microwave, radiant heat heating with an infrared heater, etc. can be preferably used. Infrared heaters are preferred because they can be heated without contact and without air flow, so that the influence on the surface to which the alkaline saponification aqueous solution is applied can be minimized. As the infrared heater, an electric, gas, oil or steam far infrared ceramic heater can be used. A commercially available infrared heater (for example, manufactured by Noritake Company Limited) may be used. An oil-type or steam-type infrared heater using oil or steam as the heat medium is preferable from the viewpoint of explosion prevention in an atmosphere in which an organic solvent coexists.

  The temperature of the cellulose ester film may be the same as or different from the temperature heated before application of the alkaline saponified aqueous solution. Further, the temperature may be changed continuously or stepwise during the saponification reaction. Film temperature becomes like this. Preferably it is 20 to 150 degreeC, More preferably, it is 25 to 100 degreeC, More preferably, it is 35 to 80 degreeC. For the detection of the film temperature, a commercially available non-contact infrared thermometer can be used, and feedback control may be performed on the heating means in order to control the temperature within the above range. The time for applying the alkaline saponification aqueous solution and keeping it in the above temperature range until washing off is preferably 1 second to 5 minutes, more preferably 2 to 100 seconds, depending on the conveyance speed described later, It is particularly preferred to hold for 3 to 50 seconds.

  It is preferable to carry out each step treatment while carrying the cellulose ester film to carry out the alkali saponification treatment, but the carrying speed of the cellulose ester film is determined by the combination of the composition of the alkali saponification aqueous solution and the coating method. Generally, 10 to 500 m / min is preferable, and 20 to 300 m / min is more preferable.

  In order to remove dust and to make the wettability of the membrane surface more uniform before the step of heating the cellulose ester film to room temperature or higher, or before the step of applying the alkaline saponification aqueous solution to the cellulose ester film. These methods that can also carry out static elimination treatment, dust removal treatment or wet treatment can use generally known methods, and examples of the static elimination method include the method described in JP-A No. 62-131500, As the dust removal method, the method described in JP-A-2-43157 can be used.

  There are generally three methods for slowing or stopping the saponification reaction between the aqueous alkaline saponification solution and the cellulose ester film after the saponification reaction is allowed to proceed while maintaining the temperature of the cellulose ester film at room temperature or higher. The first is to dilute the applied alkaline saponification aqueous solution to lower the alkali concentration and reduce the reaction rate, and the second is to lower the temperature of the cellulose ester film coated with the alkaline saponification aqueous solution to react. The third is a method of reducing the speed, and the third is a method of neutralizing with an acidic liquid.

  In order to dilute the applied aqueous solution of alkali saponification, a method of applying a diluent, a method of spraying the diluent, or a method of immersing the cellulose ester film in a container containing the diluent can be employed. The method of applying the diluting solution and the method of spraying are preferable methods for carrying out the cellulose ester film while being continuously conveyed. The method of applying the diluent is most preferable because it can be carried out using the minimum amount of diluent.

  It is desirable that the dilution liquid is applied in such a manner that the dilution liquid can be applied again on the cellulose ester film already coated with the alkaline saponification aqueous solution. For coating, a die coater (extrusion coater, slide coater), roll coater (forward roll coater, reverse roll coater, gravure coater), and rod coater (rod wound with a thin metal wire) can be preferably used. The application method is described in various documents (for example, Modern Coating and Drying Technology, Edward Cohen and Edgar B. Gutoff, Edits., VCH Publis hers, Inc, 1992). In order to reduce the alkali concentration by quickly mixing the alkali saponification aqueous solution and the diluting solution, the flow is more laminar than the die coater in the micro area where the diluting solution is applied (sometimes called coating bead). However, a roll coater or a rod coater in which the flow is not uniform is preferable.

  The purpose of the alkaline diluting solution is to reduce the alkali concentration and to prevent the extraction material such as the film additive substance from adhering to the film, so it must be a solvent that dissolves the alkaline agent in the alkaline saponification aqueous solution. Therefore, it is preferable to use water or a mixed solution of water and an organic solvent, and two or more organic solvents may be mixed and used. The organic solvent used in the alkali saponification aqueous solution described above can be used advantageously. A preferred solvent is water. Moreover, it is preferable to include a surfactant in the alkaline diluting solution so that an extraction material such as a film additive substance does not adhere to the film. Although there is no limitation in particular as surfactant, the surfactant used for the alkali saponification aqueous solution mentioned above can be utilized advantageously. In addition, the alkaline diluent contains the above-mentioned antifoaming agent to eliminate the adhesion of minute bubbles to the film surface, and the alkaline saponification aqueous solution and the alkaline dilution solution can be uniformly and uniformly washed. preferable.

The coating amount of the diluent is determined according to the concentration of the alkaline saponification aqueous solution. In the case of a die coater in which the flow in the coating bead is a laminar flow, the coating amount is preferably 1.5 to 10 times the original alkali concentration, more preferably 2 to 5 times. In the case of a roll coater or a rod coater, since the flow in the coating bead is not uniform, mixing of the alkaline saponification aqueous solution and the diluting liquid occurs, and the mixed liquid is recoated. Therefore, in this case, since the dilution rate cannot be specified by the application amount of the diluent, it is necessary to measure the alkali concentration after application of the diluent. Also in the roll coater and the rod coater, the coating amount is preferably diluted from the original alkali concentration by 1.5 to 10 times, more preferably from 2 to 5 times.

  An acid can also be used to quickly stop the saponification reaction with alkali. In order to neutralize with a small amount, it is preferable to use a strong acid. Furthermore, considering the ease of washing with water, it is preferable to select an acid having a high solubility in water for the salt produced after the neutralization reaction with the alkali. Hydrochloric acid, nitric acid, phosphoric acid, chromic acid, sulfonic acid, and methanesulfonic acid are particularly preferred. If the carbonate ion concentration or chloride ion concentration in the alkali saponification solution is high, precipitation may occur due to a rapid neutralization reaction. In this case, a buffering weak acid is added to the alkali neutralization solution. It is preferable. Examples of such weak acids include sorbitol, saccharose, glucose, galactose, arabinose, xylose, fructose, ribose, mannose and L-ascorbic acid, etc. Examples include alcohols, aldehydes, compounds having a phenolic hydroxyl group, oximes, and nucleic acid-related substances.

  In order to neutralize the applied alkaline saponification aqueous solution with an acid, a method of applying an acidic solution (alkali neutralizing solution), a method of spraying the acidic solution, or a method of immersing the cellulose ester film together in a container containing the acidic solution Can be adopted. The method of applying an acidic solution and the method of spraying are preferable when the cellulose ester film is continuously conveyed. The method of applying the acidic solution is most preferable because it can be carried out using the minimum necessary acidic solution.

  The application of the alkali neutralizing solution is desirably a continuous application method in which the acidic solution can be applied again onto the cellulose ester film already coated with the alkaline saponification aqueous solution. For coating, a die coater (extrusion coater, slide coater), roll coater (forward roll coater, reverse roll coater, gravure coater), and rod coater (rod wound with a thin metal wire) can be preferably used. The coating method is described in various documents (for example, Modern Coating and Drying Technology, Edward Cohen and Edgar B. Gutoff, Edits., VCH Publishers, Inc, 1992). In order to reduce the alkalinity by quickly mixing the alkali saponification aqueous solution and the neutralizing solution, the die coater in which the flow is laminar in a minute region (sometimes called a coating bead) where the neutralizing solution is applied A roll coater or a rod coater in which the flow is not uniform is more preferable.

  The coating amount of the alkali neutralizing solution is determined according to the type of alkali and the concentration of the alkali saponified aqueous solution. In the case of a die coater in which the flow in the coating bead is a laminar flow, the coating amount of the neutralizing solution is preferably 0.1 to 5 times the original alkali coating amount, and is 0.5 to 2 times. Further preferred. In the case of a roll coater or a rod coater, since the flow in the coating bead is not uniform, mixing of the alkaline saponification aqueous solution and the neutralizing liquid occurs, and the mixed liquid is recoated. Therefore, in this case, since the neutralization rate cannot be specified by the application amount of the neutralization liquid, it is necessary to measure the alkali concentration after application of the neutralization liquid. In a roll coater or a rod coater, the application amount of the acidic solution is preferably determined such that the pH after application of the acidic solution is 4 to 9, and more preferably 6 to 8.

  The purpose of the alkali neutralization solution is to reduce the alkalinity and prevent the extraction materials such as film additive materials from adhering to the film. I must. Therefore, it is preferable to use water or a mixed solution of water and an organic solvent, and two or more organic solvents may be mixed and used. The organic solvent used for the alkali saponification aqueous solution described above can be used significantly. A preferred solvent is water. Moreover, it is preferable to include a surfactant in the alkali neutralization solution so that an extraction material such as a film additive substance does not adhere to the film. Although there is no limitation in particular as surfactant, the surfactant used for the alkali saponification aqueous solution mentioned above can be utilized advantageously. Furthermore, it is preferable to include the above-mentioned buffering agent in the alkali neutralizing solution in order to increase the cleaning efficiency.

  It is also possible to stop the saponification reaction by lowering the temperature of the cellulose ester film. In order to promote the reaction, the saponification reaction is substantially stopped by sufficiently lowering the temperature from a state maintained at room temperature or higher. The means for lowering the temperature of the cellulose ester film is determined in consideration that one side of the cellulose ester film is wet. Collision of cold air with the opposite surface of the coating or contact heat transfer with a cooling roll can be preferably employed. The film temperature after cooling is preferably 5 ° C to 60 ° C, more preferably 10 ° C to 50 ° C, and most preferably 15 ° C to 30 ° C. The film temperature is preferably measured with a non-contact infrared thermometer. It is also possible to adjust the cooling temperature by performing feedback control on the cooling means.

(Washing process)
The washing step is performed in order to remove the alkali saponification aqueous solution, the alkali dilution liquid or the alkali neutralization liquid. If extraction materials such as alkali agents, acids, salts, film additives, etc. remain, the saponification reaction proceeds, the coating film of the alignment film and the liquid crystalline molecular layer to be applied later, and the alignment of the liquid crystal molecules Affects. Cleaning can be carried out by a method of applying cleaning water, a method of spraying cleaning water, or a method of immersing the cellulose ester film together in a container containing cleaning water. The method of applying washing water and the method of spraying are preferable for carrying out the cellulose ester film while continuously conveying it. The method of spraying the washing water is particularly preferable because turbulent mixing of the washing water on the cellulose ester film and the alkaline coating liquid can be obtained by a jet.

  The method of spraying water can be carried out by a method using an application head (for example, a fountain coater or a frog mouth coater) or a method using a spray nozzle used for air humidification, painting, or automatic tank cleaning. The coating method is described in “All about coating” edited by Masayoshi Araki, Research Institute for Processing Technology (1999). Conical or fan-shaped spray nozzles can be arranged in the width direction of the cellulose ester film so that the water flow collides with the entire width. Commercially available spray nozzles (for example, manufactured by Ikeuchi Co., Ltd., manufactured by Spraying Systems) may be used. The higher the water spray speed, the higher the turbulent mixing. However, if the speed is too high, the conveyance stability of the continuously conveyed cellulose ester film may be impaired. The collision speed of spraying is preferably 50 to 1000 cm / second, more preferably 100 to 700 cm / second, and most preferably 100 to 500 cm / second.

  The variation in the amount of water sprayed per unit time is preferably controlled to be less than 30% in both the longitudinal direction and the width direction of the cellulose ester film being conveyed. However, at both ends in the width direction of the cellulose ester film, it is often the case that the coating amount of the alkaline saponification aqueous solution and the coating amount of the acidic solution used for neutralization are large. In order to ensure the cleanability of the portion where the coating amount is large, the amount of water spraying at both ends in the width direction can be increased. When using a coating head, the clearance of the slit from which water is discharged is set wide so that the flow rate at both ends is increased. In addition, a coater having a narrow width may be separately installed in order to locally supply water films to both ends. Multiple coaters with a narrow width can be installed. Also when using a spray nozzle, a nozzle for spraying water locally can be installed at both ends.

  When a certain amount of water is used in the water washing, it is preferable to adopt a batch-type washing method in which the water is divided and applied several times rather than being applied all at once. That is, the amount of water is divided into several parts and supplied to a plurality of water washing means sequentially installed in the transport direction of the cellulose ester film. Appropriate time (distance) is provided between one water washing means and the next water washing means to dilute the alkaline coating liquid by diffusion. More preferably, if the cellulose ester film to be conveyed is inclined so that the water on the film flows along the film surface, mixed dilution by flow can be obtained in addition to diffusion. As a most preferable method, the water washing dilution efficiency can be further enhanced by providing a water draining means for removing the water film on the cellulose ester film between the water washing means and the water washing means. Specific examples of draining means include blades used for blade coaters, air knives used for air knife coaters, rods used for rod coaters, and rolls used for roll coaters. It is advantageous that the number of washing means arranged in sequence is large. However, from the viewpoint of installation space and equipment cost, usually 2 to 10 stages, more preferably 2 to 5 stages are used. The water film thickness after the draining means is preferably thin, but the minimum water film thickness is limited depending on the type of draining means used. In the method of physically contacting a solid with a cellulose ester film such as a blade, rod, or roll, even if the solid is an elastic body with low hardness such as rubber, the film surface is scratched or the elastic body is not Since it is worn out, it is necessary to leave a finite water film as a lubricating fluid. Usually, a water film of preferably several μm or more, more preferably 10 μm or more is left as a lubricating fluid.

  An air knife is preferable as the draining means that can reduce the thickness of the water film to the limit. By setting a sufficient air volume and pressure, the water film thickness can be brought close to zero. However, if the amount of air blown out is too large, it may affect the transport stability of the cellulose ester film, such as flapping of the transport film and deviation to one side, so there is a preferable range. Although depending on the original water film thickness on the cellulose ester film and the film conveyance speed, the wind speed is preferably 10 to 500 m / second, more preferably 20 to 300 m / second, more preferably 30 to 200 m / second. . In order to remove the water film uniformly, the air supply to the air knife outlet and the air knife is adjusted so that the wind speed distribution in the width direction of the cellulose ester film is usually within 10%, preferably within 5%. Adjust the method. The narrower the gap between the surface of the cellulose ester film to be conveyed and the air knife outlet, the better the draining ability, but there is an appropriate range because the possibility of damage due to contact with the cellulose ester film increases. Usually, the air knife is installed with a gap of preferably 10 μm to 10 cm, more preferably 100 μm to 5 cm, and even more preferably 500 μm to 1 cm. Furthermore, by setting up a backup roll on the side opposite to the water-washed surface of the cellulose ester film so as to face the air knife, the setting of the gap can be stabilized and the influence of fluttering, wrinkles, deformation, etc. of the film can be reduced. It is preferable because it is possible.

  It is preferable to use pure water as the washing water. The pure water used in the present invention has a specific electric resistance of at least 0.1 MΩ or more, particularly metal ions such as sodium, potassium, magnesium and calcium are less than 1 mg / L, and anions such as chlorochloro ion and nitrate ion are It is preferably less than 0.1 mg / L. Pure water can be obtained by a reverse osmosis membrane, an ion exchange resin, a simple substance such as distillation, or a combination thereof. The higher the washing water temperature, the higher the washing ability. However, in the method of spraying water on the cellulose ester film to be transported, the area of water that comes into contact with air is large, and the evaporation becomes more significant as the temperature increases, so that the surrounding humidity increases and the risk of condensation increases. For this reason, the temperature of the washing water is preferably set in the range of 5 to 90 ° C, more preferably 20 to 80 ° C, and further preferably 25 to 60 ° C.

  If the components of the alkaline saponification aqueous solution or the product of the saponification reaction are not easily soluble in water, a solvent washing step for removing water-insoluble components may be added before or after the water washing step. In the solvent washing step, the water washing method and draining means described above can be used. As the organic solvent to be used, in addition to the solvents that can be used in the above-mentioned alkaline saponification aqueous solution, the solvents described in the new edition solvent pocket book (Ohm, 1994) can be used.

  A drying step can also be performed after the washing step. Usually, the water film can be sufficiently removed by means of draining water such as an air knife, and a drying step may not be necessary. However, before the cellulose ester film is wound into a roll, it is dried by heating to adjust to a preferred moisture content. May be. Conversely, the humidity can be adjusted with a wind having a set humidity. The temperature of the drying air is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 50 to 120 ° C. The cellulose ester film that has been subjected to electron beam treatment and alkali saponification treatment can be coated with a functional layer continuously after the alkali saponification treatment step described above. By applying a saponification treatment to one side by coating and coating the functional layer on it, even if the film is wound into a roll after the functional layer has been provided, it is between the functional layer surface and the opposite surface of the film. It can prevent sticking.

[Protective film]
The cellulose ester film laminate of the present invention has a structure in which a protective film is laminated on at least one side of the cellulose ester film. The protective film in the present invention is a film having a function of protecting the cellulose ester film, and includes a tape-like film. The protective film in this invention is not necessarily limited to the film laminated | stacked only in order to protect a cellulose-ester film, You may have another function together. The structure of the protective film in the present invention is not particularly limited. For example, a laminated film in which an adhesive layer is provided on one side of a resin base material, a resin film coated with an adhesive, and a coextrusion in which one side is an adhesive layer A film etc. are mentioned as a preferable example. As the resin substrate of the protective film, conventionally used optical protective films can be used without particular limitation. In general, from the viewpoints of inspection properties and manageability of optical films by fluoroscopy, as a resin base material, for example, polyester resin, cellulose resin, acetate resin, polyethersulfone resin, polycarbonate resin It is preferable to use a transparent polymer such as a polyamide resin, a polyimide resin, a polyolefin resin, or an acrylic resin.

  Of these, polyester resins are preferred. As the resin base material, a laminate of one or more kinds of resins can be used, and a stretched resin base material can also be used. The thickness of the base material of the protective film is generally 500 μm or less, preferably 10 to 200 μm. It is preferable to use a resin base material having high heat resistance, and it is preferable to use a film that exhibits a heat distortion temperature of 100 ° C. or higher and is tough. When the heat distortion temperature is 100 ° C. or higher, the cellulose ester film is hardly deformed or curled due to deformation of the protective film substrate even when exposed to high temperature by heat drying or UV irradiation. Preferred resin base materials include polyethylene terephthalate (hereinafter abbreviated as “PET”), polyethylene (hereinafter abbreviated as “PE”), polypropylene, polycarbonate, polyethylene naphthalate, polyimide, and the like.

  The kind of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer applied to the protective film substrate is not particularly limited, and is acrylic, ethylene-vinyl acetate copolymer resin, styrene-ethylene-butylene copolymer resin, styrene-isoprene-styrene. Block copolymer resin, rosin resin, terpene resin, aromatic petroleum resin, polybutene, polyisobutene, coumarone-indene resin, phenol resin, xylene resin, low density polyethylene, medium density polyethylene, linear low density polyethylene, ethylene -Alpha olefin copolymer resin, styrene-butadiene copolymer resin, acrylic rubber, natural rubber, silicone rubber, synthetic rubber, etc. are mentioned, These are used individually or in mixture of 2 or more.

  Since the protective film may be exposed to a high temperature in the drying process, it is preferable to use a pressure-sensitive adhesive that does not develop adhesion even after being exposed to a high temperature in the present invention. Examples of such adhesives include, but are not limited to, acrylic, rubber-based, and silicone-based adhesives. From the viewpoint of transparency, weather resistance, heat resistance, etc., an ethylene-vinyl acetate copolymer (EVA) or an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer is preferably used. In the case of an acrylic polymer, those having a mass average molecular weight of about 300,000 to 2.5 million are preferable.

  Examples of the monomer used for preparing the acrylic polymer include various alkyl (meth) acrylates. For example, (meth) acrylic acid alkyl ester (for example, methyl ester, ethyl ester, propyl ester, butyl ester, 2-ethylhexyl ester, isooctyl ester, isononyl ester, isodecyl ester, dodecyl ester, lauryl ester, tridecyl ester , Pentadecyl ester, hexadecyl ester, heptadecyl ester, octadecyl ester, nonadecyl ester, eicosyl ester, etc. alkyl ester having 1 to 20 carbon atoms), and these may be used alone or in combination. it can.

  In addition, in order to impart polarity to the resulting acrylic polymer, together with the (meth) acrylic acid alkyl ester, carboxyl group-containing monomers such as (meth) acrylic acid and itaconic acid; hydroxyethyl (meth) acrylate, ( Hydroxyl group-containing monomers such as (meth) hydroxypropyl acrylate; Amide group-containing monomers such as N-methylolacrylamide; Cyano group-containing monomers such as (meth) acrylonitrile; Epoxy such as glycidyl (meth) acrylate Group-containing monomers; vinyl esters such as vinyl acetate; styrene monomers such as styrene and α-methylstyrene can be used as copolymer monomers. The polymerization method for the acrylic polymer is not particularly limited, and a known polymerization method such as solution polymerization, emulsion polymerization, suspension polymerization, or UV polymerization can be employed.

  Moreover, the said adhesive may contain the crosslinking agent. Examples of the crosslinking agent include polyisocyanate compounds, polyamine compounds, melamine resins, urea resins, and epoxy resins. Further, the pressure-sensitive adhesive suitably uses a tackifier, a plasticizer, a filler, an antioxidant, a UV absorber, a UV absorber, a light / heat stabilizer, a dye, a silane coupling agent, etc. You can also For example, a fatty acid ester may be added to the pressure-sensitive adhesive layer. In that case, the fatty acid preferably has 11 or more carbon atoms as the ester obtained by the condensation reaction of fatty acid and alcohol, and has an unsaturated bond in the molecule. It may have a functional group such as an isocyanate group or an epoxy group. Examples of the alcohol include monohydric alcohols having 1 to 18 carbon atoms and polyhydric alcohols such as ethylene glycol and glycerin. As for content of fatty acid ester, 0.5-7 mass parts is preferable with respect to 100 mass parts of adhesives. If the amount is 0.5 parts by mass or more, adhesion progress hardly occurs, and if it is 7 parts by mass or less, contamination of the adherend surface after peeling is easily suppressed.

  The method for forming the pressure-sensitive adhesive layer is not particularly limited, and is a method in which a pressure-sensitive adhesive is applied to a release liner, dried and then transferred to a resin substrate (transfer method), and a pressure-sensitive adhesive is directly applied to a resin substrate and dried. Method (direct copy method) and the like. The thickness (dry film thickness) of the pressure-sensitive adhesive layer is determined according to the required adhesive force. Usually, it is about 1-100 micrometers, Preferably it is 5-50 micrometers. Although the thickness of the resin base material of a protective film is not specifically limited, 10-150 micrometers is preferable. If it is 10 μm or more, it has a sufficient supporting ability and is difficult to tear at the time of peeling. If it is 150 μm or less, it is relatively easy to peel off and the cellulose ester film is not easily broken. Although the thickness of the adhesive layer of a protective film is not specifically limited, 0.5-40 micrometers is preferable. If it is 0.5 μm or more, it is difficult to entrain air at the time of lamination, and if it is 40 μm or less, an appropriate peel strength can be easily achieved.

  In order to laminate the protective film on the cellulose ester film in the present invention, it is preferable that the cellulose ester film and the protective film are brought into contact with each other at an appropriate pressure while air is not trapped, and laminated with the adhesiveness of the protective film. . At this time, a nip roll for laminating used when laminating a normal protective film is used. Using a nip roll that combines a rubber roll and a metal roll, or a nip roll that combines a rubber roll and a rubber roll, for example, bring the cellulose ester film and the protective film into a Y shape, and join the nip roll in a state in which both of them are partially aligned. Can be laminated. The thickness variation of the laminate in which the protective film is laminated on the cellulose ester film is preferably 3 μm or less.

  The widths of the cellulose ester film and the protective film used when laminating may be the same or different. In the present invention, the ratio of the width of the cellulose ester film to the width of the protective film is preferably 1: 0.1 to 1.1, more preferably 1: 1.05 to 1.1, and 1: More preferably, it is 0.8-1.0. By setting the ratio between the width of the cellulose ester film and the width of the protective film within a preferable range, advantageous effects can be obtained in terms of film stickability and transportability.

It is preferable that the peeling force required to peel both from the laminate of the protective film and the cellulose ester film is 2 to 35 × 10 ⁻³ N / 25 mm width. The peeling force here refers to the peeling force after coating. If it is 2 × 10 ⁻³ N / 25 mm width or more, it is difficult to peel off during conveyance, and if it is 35 × 10 ⁻³ N / 25 mm width or less, cracks and breakage are not easily generated when peeling, and it is easy to peel off.

[Characteristics of cellulose ester film]
Below, it describes about the characteristic of the cellulose-ester film which comprises the laminated body of this invention.

(Residual solvent amount)
The residual solvent amount of the cellulose ester film constituting the laminate of the present invention is 0.01% by mass or less. The amount of residual solvent is more preferably 0.005% by mass or less, further preferably 0.001% by mass or less, and particularly preferably not detected. If a cellulose ester film is formed by a melt film forming method according to the production method of the present invention, a film having a residual solvent amount of 0.01% by mass or less can be obtained. The amount of residual solvent in the film can be measured using gas chromatography.

(Surface shape)
In the cellulose ester film constituting the laminate of the present invention, no streak-like light leakage is observed with the naked eye. Here, “no streak-like light leakage is observed with the naked eye” means that the cellulose ester film is sandwiched between two orthogonal polarizing films and light leakage observed by visual observation is 0.5 mm or longer. This means that no streak-like light leakage having a thickness is observed. The cellulose ester film constituting the laminate of the present invention is more preferably one in which no streaky light leakage having a length of 0.3 mm or more is observed, and a streaky shape having a length of 0.2 mm or more. More preferably, no light leakage is observed, and particularly preferably no streak-like light leakage is observed.

(Thickness)
The film thickness of the cellulose ester film constituting the laminate of the present invention is preferably 20 to 200 μm, more preferably 20 μm to 160 μm, still more preferably 30 μm to 120 μm, and particularly preferably 40 to 120 μm. The angle θ formed by the film forming direction (longitudinal direction) and the slow axis of Re of the film is preferably as close to 0 °, + 90 °, or −90 °. The thickness unevenness of the cellulose ester film constituting the laminate of the present invention is preferably 0 to 5 μm in both the thickness direction and the width direction, more preferably 0 to 3 μm, and still more preferably 0 to 2 μm.

(optical properties)
The front retardation (Re) at a wavelength of 590 nm of the cellulose ester film constituting the laminate of the present invention is preferably 0 to 300 nm, and the retardation (Rth) in the thickness direction is -300 to 700 nm. preferable. More preferably, the front retardation (Re) is from 0 to 250 nm and the retardation in the thickness direction (Rth) is from -200 to 500 nm. Particularly preferably, the front retardation (Re) is 0 to 250 nm and the retardation (Rth) in the thickness direction is −150 to 300 nm. The Re unevenness is preferably 0 to 10 nm, more preferably 0 to 5 μm, and still more preferably 0 to 3 μm. Rth unevenness is preferably 0 to 10 nm, more preferably 0 to 5 nm, and still more preferably 0 to 2 nm. The cellulose ester film which is the substrate of the cellulose ester film laminate of the present invention is extremely preferable as a protective film for a polarizer when it has these optical properties.

In the present specification, Re and Rth respectively represent in-plane retardation and retardation in the thickness direction at a wavelength of 590 nm. Re is measured in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments) by making light with a wavelength of 590 nm incident in the normal direction of the film unless otherwise specified.
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth is calculated by the following method.
Rth is defined as Re, with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (in the absence of the slow axis, any direction in the film plane is the rotation axis). )) From the normal direction to -50 ° to + 50 ° with respect to the normal direction of the film, and incident light of wavelength 590 nm from each inclined direction in steps of 10 °, measuring a total of 11 points. KOBRA 21ADH or WR calculates based on the retardation value, the average refractive index, and the input film thickness value.
In addition, in the case of a film having a retardation value of zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, the retardation value at a tilt angle larger than that tilt angle. After changing its sign to negative, KOBRA 21ADH or WR calculates.
In addition, the retardation value is measured from two inclined directions with the slow axis as the tilt axis (rotary axis) (in the case where there is no slow axis, the arbitrary direction in the film plane is the rotary axis), Based on the value, the average refractive index, and the input film thickness value, Rth can also be calculated from the following equations (b) and (c).

［式中、Ｒｅ（θ）は法線方向から角度θ傾斜した方向におけるレタ−デーション値をあらわす。また、ｎｘは面内における遅相軸方向の屈折率を表し、ｎｙは面内においてｎｘに直交する方向の屈折率を表し、ｎｚはｎｘおよびｎｙに直交する方向の屈折率を表す。］
式（ｃ）： Ｒｔｈ＝(（ｎｘ＋ｎｙ）／２−ｎｚ)×ｄ
測定されるフィルムが一軸や二軸の屈折率楕円体で表現できないもの、いわゆる光学軸（ｏｐｔｉｃ ａｘｉｓ）がないフィルムの場合には、以下の方法によりＲｔｈは算出される。
Ｒｔｈは前記Ｒｅを、面内の遅相軸（ＫＯＢＲＡ ２１ＡＤＨまたはＷＲにより判断される）を傾斜軸（回転軸）としてフィルム法線方向に対して−５０度から＋５０度まで１０度ステップで各々その傾斜した方向から波長５９０ｎｍの光を入射させて１１点測定し、その測定されたレターデーション値と平均屈折率および入力された膜厚値を基にＫＯＢＲＡ ２１ＡＤＨまたはＷＲが算出する。
これら平均屈折率と膜厚を入力することで、ＫＯＢＲＡ ２１ＡＤＨまたはＷＲはｎｘ、ｎｙ、ｎｚを算出する。この算出されたｎｘ、ｎｙ、ｎｚよりＮｚ＝（ｎｘ−ｎｚ）／（ｎｘ−ｎｙ）がさらに算出される。

[In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. Further, nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, and nz represents the refractive index in the direction perpendicular to nx and ny. ]
Formula (c): Rth = ((nx + ny) / 2−nz) × d
When the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film without a so-called optical axis, Rth is calculated by the following method.
Rth is the Re in 10 degree steps from −50 degrees to +50 degrees with respect to the normal direction of the film, with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis). Eleven light points with a wavelength of 590 nm are incident from the inclined direction, and KOBRA 21ADH or WR is calculated based on the measured retardation value, average refractive index, and input film thickness value.
By inputting these average refractive index and film thickness, KOBRA 21ADH or WR calculates nx, ny, and nz. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

  Moreover, it is preferable that the cellulose ester film which is a board | substrate of the cellulose-ester film laminated body of this invention has a small difference of the optical characteristic of 10% of relative humidity in 25 degreeC, and an optical characteristic of 80%. The cellulose ester film constituting the laminate of the present invention preferably has an optical slow axis parallel or perpendicular to the casting direction or the width direction. In particular, when the stretching treatment is performed, the stretching direction is preferably closer to 0 °, specifically 0 ± 3 °, more preferably 0 ± 1.5 °, and still more preferably. Is 0 ± 0.5 °. When stretched in the width direction, 90 ± 3 ° or −90 ± 3 ° is preferable, more preferably 90 ± 1.5 ° or −90 ± 1.5 °, and still more preferably 90 ± 0.5 ° or − 90 ± 0.5 °.

  The cellulose ester film constituting the laminate of the present invention preferably has a transmittance of 90% or more, more preferably 91% or more, and particularly preferably 92% or more. The cellulose ester film constituting the laminate of the present invention preferably has a haze in the range of 0 to 1.5%, more preferably 0 to 1.2%, and even more preferably 0 to 0.8%. In particular, 0.1 to 0.5% is preferable. From the above viewpoint, the cellulose ester film constituting the laminate of the present invention has a haze of 0.1 to 1.2%, a visible light transmittance of 91% or more, and a 25 ° C./relative humidity 60% environment. It is particularly preferable that the intrinsic birefringence in the in-plane direction at a wavelength of 590 nm is 0 to 0.001, and the absolute value of the intrinsic birefringence in the thickness direction is 0 to 0.003.

[Functionalization of cellulose ester film]
The cellulose ester film that is the substrate of the cellulose ester film laminate of the present invention can be functionalized by various means. For example, a layer having a specific function (functional layer) can be further formed. In particular, each optical film is composed by combining the functional layers described in detail on pages 32 to 45 of the Japan Society of Invention Disclosure Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Japan Association of Inventions). Is preferred. Among these, application of a polarizing film (polarizing plate), application of an optical compensation layer (optical compensation sheet), and application of an antireflection layer (antireflection film) are preferable. The application of these functional layers may be already performed when the cellulose ester film laminate of the present invention is produced, or the cellulose ester film is taken out of the cellulose ester film laminate of the present invention and then applied to the film. You may do it for.
When forming a functional layer, a surfactant is preferably used. The surfactant used for forming the functional layer is classified into a dispersant, a coating agent, a wetting agent, an antistatic agent and the like depending on the purpose of use. In the present invention, any nonionic or ionic (anion, cation, betaine) surfactant can be used. Further, a fluorine-based low molecular surfactant is also preferably used as a coating agent or an antistatic agent in an organic solvent.

(1) Application | coating of an adhesive layer An adhesive layer can be formed in the cellulose-ester film which is a board | substrate of the cellulose-ester film laminated body of this invention. The adhesive layer is formed for the purpose of bonding the cellulose ester film and the functional layer (ultraviolet absorbing layer). For example, there is a method of forming an adhesive layer (undercoat layer) after applying some surface treatment to the cellulose ester film or without applying a surface treatment, and further applying a functional layer thereon. Various arrangements have been made for the composition of the undercoat layer. For example, a single-layer method in which one undercoat layer is composed of one layer, or a first undercoat layer that adheres well to a cellulose ester film as a support. There is a so-called multi-layer method in which an undercoat second layer which is provided and adheres well to the functional layer as a second layer is applied thereon. In order to adhere the functional layer, the adhesive layer is not necessarily formed. For example, it is possible to employ a method in which the cellulose ester film surface is activated and then a functional layer is directly applied on the cellulose ester film to obtain an adhesive force.

(2) Giving a slipping layer A slipping layer can be formed on the cellulose ester film that is the substrate of the cellulose ester film laminate of the present invention. The sliding layer is particularly preferably formed in the outermost layer. The slipping layer can be formed by forming a layer to which a slipping agent is added. The slip agent can be contained in layers other than the slip layer. Examples of the slip agent used include polyorganosiloxanes as disclosed in JP-B-53-292; higher fatty acid amides as disclosed in US Pat. No. 4,275,146; Higher fatty acid esters (fatty acids having 10 to 24 carbon atoms) such as those disclosed in JP-A-58-33541, British Patent No. 927,446 or JP-A-55-126238 and 58-90633. And esters of alcohols having 10 to 24 carbon atoms); higher fatty acid metal salts as disclosed in U.S. Pat. No. 3,933,516; as disclosed in JP-A-58-50534 Esters of linear higher fatty acids and linear higher alcohols; as disclosed in WO 90 / 108115.8 Higher fatty acids containing an alkyl group - higher alcohol esters and the like are known.

(3) Application of conductive layer A conductive layer may be formed on the cellulose ester film constituting the laminate of the present invention. In that case, at least one type of conductive inorganic material and / or at least one type of organic material may be formed. It is a layer containing a conductive material (for example, an ionic conductive material). More preferably, the conductive layer is a layer containing a conductive metal oxide or a conductive polymer. The conductive layer may be a transparent conductive film formed by vapor deposition or sputtering. Examples of preferred metal oxides that are conductive inorganic materials include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₂ , MgO, BaO, MoO ₂ , V ₂ O _5, etc. These composite oxides are preferable, and ZnO, SnO ₂ , Sb ₂ O ₃ , and V ₂ O ₅ are particularly preferable. It is effective that Al, In, Ta, Sb, Nb, Ag, Cl, Br, and I are added to the composite oxide as heterogeneous atoms, and the addition amount ranges from 0.01 mol% to 25 mol%. Is preferred. Preferred examples of the composite oxide containing different atoms include, for example, ZnO with addition of Al, In, etc., SnO ₂ with addition of Sb, Nb, halogen elements, etc., with respect to TiO ₂ . The thing which added Nb, Ta, etc. is mentioned. The amount of these different atoms added is preferably in the range of 0.01 mol% to 30 mol%, but particularly preferably 0.1 mol% to 10 mol%.

The volume resistivity of these conductive metal oxide powders is preferably 10 ⁷ Ω · cm or less, more preferably 10 ⁵ Ω · cm or less, particularly 10 ³ Ω · cm or less. Is preferred. The primary particle size is preferably 50 to 0.2 μm, particularly preferably 50 to 0.1 μm. In addition, the conductive layer contains a powder having a specific structure whose major structure has a major axis of 100 to 6 μm (for example, needle-like) in a volume fraction of 0.01% to 80%. preferable. The amount of the conductive fine particles is preferably 0.001~5.0g / m ^2, in particular 0.005~1g / m ² is preferred. These oxides are described in JP-A Nos. 56-143431, 56-120519, and 58-62647. Furthermore, as described in Japanese Examined Patent Publication No. 59-6235, a conductive material in which the above metal oxide is attached to other crystalline metal oxide particles or fibrous materials (for example, oxidized spherical carbon black) is used. May be. The particle size that can be used is preferably 10 μm or less, but in particular, when it is 2 μm or less, stability after dispersion is good and easy to use.

(4) Application of polarizing film A polarizing film may be applied to the cellulose ester film constituting the laminate of the present invention to form a polarizing plate.
(Material used for polarizing film)
Currently, polarizing films (polarizers) used in commercially available polarizing plates are obtained by immersing the stretched polymer in a solution of iodine or dichroic dye in the bath and penetrating iodine or dichroic dye into the binder. It is common to make it. As the polarizing film, a coating type polarizing film represented by Optiva Inc. can also be used. Iodine and dichroic dye in the polarizing film exhibit polarizing performance by being oriented in the binder. As the dichroic dye, an azo dye, stilbene dye, pyrazolone dye, triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye or anthraquinone dye is used. The dichroic dye is preferably water-soluble. The dichroic dye preferably has a hydrophilic substituent (for example, a sulfo group, an amino group, or a hydroxyl group). For example, the compounds described in page 58 of the Japan Society for Invention Disclosure Technique (Public Technical No. 2001-1745, published on March 15, 2001, Japan Society for Invention) are mentioned.

  The polarizing film is not particularly limited as long as it has a thickness of 35 μm or less, and various types can be used. Examples of the polarizing film include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, ethylene / vinyl acetate copolymer partially saponified films, and dichroic substances such as iodine and dichroic dyes. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizing film composed of a polyvinyl alcohol film and a dichroic substance such as iodine is preferable. Particularly, the dyeability of a polyvinyl alcohol film dyed with iodine is favorable and suitable.

  A polarizing film having a thickness of 30 μm or less can be formed, for example, by dyeing, crosslinking, stretching, and drying a polyvinyl alcohol film having a thickness of 100 μm or less with iodine.

  As the polyvinyl alcohol film, a film formed by any method such as a casting method, a casting method, an extrusion method, etc., in which a stock solution in which a polyvinyl alcohol resin is dissolved in water or an organic solvent is cast is used. be able to. 100-5000 are preferable and, as for the polymerization degree of a polyvinyl alcohol-type resin, 1400-4000 are more preferable. The film thickness of a polyvinyl alcohol-type film is 100 micrometers or less, Preferably it is 20-90 micrometers, More preferably, it is 20-85 micrometers. When the film thickness exceeds 100 μm, the color change of the display panel becomes large when mounted on a liquid crystal display device or the like. On the other hand, when the film thickness is too thin, stretching becomes difficult.

  In the dyeing process, the polyvinyl alcohol film is immersed in a dyeing bath at 20 to 70 ° C. to which iodine is added for 1 to 20 minutes to adsorb iodine. The iodine concentration in the dyeing bath is usually 0.1 to 1 part by mass per 100 parts by mass of water. In order to increase the dyeing efficiency, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide are used in the dye bath. An auxiliary such as iodide such as tin and titanium iodide is preferably added in an amount of 0.02 to 20 parts by mass, more preferably 2 to 10 parts by mass. The dyeing bath may contain a small amount of an organic solvent compatible with water in addition to the water solvent. The polyvinyl alcohol film may be swelled at 20 to 60 ° C. for 0.1 to 10 minutes in a water bath or the like before being dyed in iodine or a dichroic dye-containing aqueous solution.

  In the crosslinking step, the dyed polyvinyl alcohol film is stretched in a boron compound-containing aqueous solution. The boron compound-containing aqueous solution usually contains 1 to 10 parts by mass of a polyvinyl alcohol crosslinking agent such as boric acid, borax, glyoxal, and glutaraldehyde alone or mixed with 100 parts by mass of water. In aqueous solution containing boron compound, in order to obtain in-plane uniform characteristics, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, steel iodide, barium iodide An assistant such as iodide such as calcium iodide, tin iodide and titanium iodide may be added in an amount of preferably 0.05 to 15% by mass, more preferably 0.5 to 8% by mass. The temperature of the boron compound-containing aqueous solution is usually 20 to 70 ° C, preferably 40 to 60 ° C. The immersion time is not particularly limited, but is usually 1 second to 15 minutes, preferably 5 seconds to 10 minutes. The boron compound-containing aqueous solution may contain a small amount of an organic solvent compatible with water in addition to the aqueous solvent.

  In the drying step, the polyvinyl alcohol film subjected to the iodine adsorption alignment treatment is further iodide having a water temperature of preferably 10 to 60 ° C., more preferably 30 to 40 ° C., and a concentration of preferably 0.1 to 10% by mass. After immersing in an aqueous iodide solution such as potassium, usually for 1 second to 1 minute, washed with water, and usually dried at 20 to 80 ° C. for 1 minute to 10 minutes to obtain a polarizing film. In the iodide aqueous solution, auxiliary agents such as zinc sulfate and zinc chloride may be added.

  In the case of the stretching method, the stretching ratio is preferably 3.0 to 20.0 times, more preferably 3.0 to 10.0 times. Stretching can be performed by dry stretching in air (stretching performed in an environment having a relative humidity of 10% or less). Moreover, you may implement wet extending | stretching in the state immersed in water. The stretch ratio of dry stretching is preferably 3.0 to 10.0 times, and the stretch ratio of wet stretching is preferably 3.0 to 7.5 times. When the total stretch ratio of wet stretching is less than 3.0 times, it is difficult to obtain a polarizing plate having a high degree of polarization, and when it exceeds 7.5 times, the film tends to break. The stretching ratio here is (length of polarizing film after stretching) / (length of polarizing film before stretching). The stretching direction may be performed parallel to the longitudinal direction (parallel stretching), or may be performed in an oblique direction (oblique stretching). These stretching methods are not particularly limited with respect to the stretching method, the number of stretchings, and the like, and may be performed in each step of dyeing and crosslinking, or may be performed in any one step. Moreover, you may carry out in multiple times by the same process.

(I) Parallel Stretching Method In the parallel stretching method, it is preferable to swell the PVA film prior to stretching. The degree of swelling is 1.2 to 2.0 times (mass ratio before swelling and after swelling). Thereafter, it is preferably stretched at a bath temperature of 15 to 50 ° C., especially 17 to 40 ° C. in an aqueous medium bath or a dye bath for dissolving a dichroic substance while being continuously conveyed through a guide roll or the like. . Stretching can be achieved by gripping with two pairs of nip rolls and increasing the conveyance speed of the subsequent nip roll to be higher than that of the previous nip roll.

(II) Diagonal Stretching Method In the oblique stretching method, a method of stretching using a tenter protruding in an oblique direction in an oblique direction described in JP-A-2002-86554 can be used. Since this stretching is performed in the air, it is necessary to make it easy to stretch by adding water in advance. The moisture content is preferably 5% to 100%, the stretching temperature is preferably 40 ° C to 90 ° C, and the humidity during stretching is preferably 50% to 100% in terms of relative humidity.
The absorption axis of the polarizing film thus obtained is preferably 10 ° to 80 °, more preferably 30 ° to 60 °, and still more preferably 45 ° (40 ° to 50 °).

  In addition, the moisture content of the polarizing film when bonded to the protective film (the water mass ratio in the polarizing film in the total mass of the polarizing film) is generally less than 20% by mass, although it depends on the thickness of the polarizing film, A range of 5 to 20% by mass, particularly 13 to 17% by mass is preferable. When the moisture content exceeds 20% by mass, the amount of moisture change after the production of the polarizing plate is increased, which adversely affects the decrease in the degree of polarization and the durability in a high temperature and high humidity environment.

(Lamination)
A polarizing plate is produced by laminating a cellulose ester film constituting the laminate of the present invention and a polarizing film prepared by stretching. There are no particular restrictions on the direction of bonding, but it is preferred that the direction of the casting axis of the cellulose ester film and the direction of the stretching axis of the polarizing plate be 0 °, 45 °, or 90 °. The adhesive for bonding is not particularly limited, but examples thereof include PVA resins (including modified PVA such as acetoacetyl group, sulfonic acid group, carboxyl group, oxyalkylene group) and boron compound aqueous solution. preferable. The thickness of the adhesive layer is preferably 0.01 to 10 μm after drying, and particularly preferably 0.05 to 5 μm.
Examples of the laminated layer structure include the following.
B) A / P / A
B) A / P / B
C) A / P / T
D) B / P / B
E) B / P / T
“A” is an unstretched cellulose ester film constituting the laminate of the present invention, “B” is a stretched cellulose ester film constituting the laminate of the present invention, and “T” is a cellulose triacetate film (Fuji Photo Film Co., Ltd.). ), Manufactured by Fujitac TD80U, etc.), “P” indicates a polarizing film.

  In the case of the constitution (b), A and B may be the same composition or different cellulose esters. In the case of the configuration (a), A may be a cellulose ester having the same composition or different, and may be the same or different. In the case of the above-mentioned constitution d), B may be a cellulose ester having the same composition or different, and may be the same or different. When the polarizing plate of the present invention is incorporated in a liquid crystal display device, either may be used as the liquid crystal surface, but in the case of constitution b) or e), it is more preferable that B is on the liquid crystal side. When the polarizing plate of the present invention is incorporated in a liquid crystal display device, a substrate containing liquid crystal is usually disposed between two polarizing plates. In this case, the polarizing plates of the present invention (i) to (e) and normal polarization Plates (T / P / T) can be freely combined. However, it is preferable to provide a transparent hard coat layer, an antiglare layer, an antireflection layer, and the like on the film on the outermost surface of the display side of the liquid crystal display device.

(Characteristics and application of polarizing plate)
The polarizing plate thus obtained preferably has a higher light transmittance and a higher degree of polarization. The transmittance of the polarizing plate of the present invention is preferably 42.0% or more, specifically, preferably 42% to 50%, more preferably 42.5% to 50%, and still more preferably. It is in the range of 43.0% to 50%, most preferably 43.5% to 50%. The degree of polarization is preferably 99.0% or more, specifically, preferably in the range of 99% to 100%, more preferably 99.5% to 100%, and still more preferably 99. It is in the range of 6% to 100%, most preferably 99.9% to 100%. Furthermore, the polarizing plate of the present invention thus obtained can be laminated with a λ / 4 plate to produce circularly polarized light. In this case, lamination is performed so that the slow axis of λ / 4 and the absorption axis of the polarizing plate are 45 °. At this time, λ / 4 is not particularly limited, but more preferably has a wavelength dependency such that the lower the wavelength, the smaller the retardation. Furthermore, it is preferable to use a polarizing film having an absorption axis inclined by 20 ° to 70 ° with respect to the longitudinal direction and a λ / 4 plate made of an optically anisotropic layer made of a liquid crystalline compound. A protective film may be bonded to one surface of these polarizing plates, and a separate film may be bonded to the other surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection.

(5) Preparation of antireflection film (configuration of antireflection film)
The antireflection film of the present invention has at least one hard coat layer and a low refractive index layer located on the outermost layer on one side of the cellulose ester film constituting the laminate of the present invention. As a preferable laminated structure of the antireflection film of the present invention, a structure having layers in the order of a transparent support, a hard coat layer, a medium refractive index layer, a high refractive index layer and a low refractive index layer can be mentioned. The refractive indexes of the transparent support, the middle refractive index layer, the high refractive index layer, and the low refractive index layer satisfy the following relationship.
Refractive index of low refractive index layer <Refractive index of transparent support <Refractive index of medium refractive index layer <Refractive index of high refractive index layer Also, an antiglare hard coat layer between the hard coat layer and the low refractive index layer May be provided. A configuration having layers in the order of a hard coat layer, a light diffusing (internal scattering) hard coat layer, a high refractive index layer, and a low refractive index layer is also preferred.

  As an example of a preferable laminated structure of the antireflection film of the present invention, a cellulose ester film support, a hard coat layer, a light diffusing (internal scattering, antiglare) hard coat layer, and a low refractive index layer are arranged in this order. The thing which has a structure is mentioned. The hard coat layer is also preferably composed of only one light diffusing (internal scattering, anti-glare) hard coat layer. The low refractive index layer is disposed so as to be located on the outermost side. In the light diffusing (internal scattering, antiglare) hard coat layer, particles imparting light diffusing (internal scattering) are dispersed. In the present invention, the hard coat layer may be a combination of a hard coat layer having light diffusibility (internal scattering) and a hard coat layer not having light diffusibility (internal scattering), and has anti-glare properties. A combination of a hard coat layer and a hard coat layer that does not have antiglare properties may be used, one of the hard coat layers may be formed, or a plurality of layers, for example, two to four layers may be formed.

  The strength of the antireflection film of the present invention is preferably H or more, more preferably 2H or more, and most preferably 3H or more in a pencil hardness test according to JIS K5400. The antireflection film of the present invention preferably has a haze value of 3 to 30%, more preferably 4 to 15%, and an average reflectance of 450 nm to 650 nm, preferably 1.8% or less, more preferably It is 1.5% or less, more preferably 1.2% or less. When the haze value and the average reflectance are in the above range, good antiglare property and antireflection property can be obtained without deteriorating the transmission image.

(High refractive index layer and medium refractive index layer)
The layer having a high refractive index of the antireflection film is composed of a curable film containing at least an inorganic compound ultrafine particle having a high refractive index having an average particle size of 100 nm or less and a matrix binder.
Examples of the high refractive index inorganic compound fine particles include inorganic compounds having a refractive index of 1.65 or more, preferably those having a refractive index of 1.9 or more. Examples thereof include oxides such as Ti, Zn, Sb, Sn, Zr, Ce, Ta, La, and In, and composite oxides containing these metal atoms. In order to obtain such ultrafine particles, the surface of the particles is treated with a surface treatment agent (for example, silane coupling agents, etc .: JP-A-11-295503, JP-A-11-153703, JP-A-2000-9908). No., anionic compound or organometallic coupling agent: Japanese Patent Laid-Open No. 2001-310432, etc., core-shell structure with high refractive index particles as a core (Japanese Patent Laid-Open No. 2001-166104, etc.), specific dispersion (For example, JP-A-11-153703, US Pat. No. 6,210,858B1, JP-A-2002-27776069, etc.) and the like.

  Examples of the material forming the matrix include conventionally known thermoplastic resins and curable resin films. Furthermore, a group consisting of a polyfunctional compound-containing composition containing at least two radically polymerizable and / or cationically polymerizable groups, an organometallic compound containing a hydrolyzable group, and a partial condensate composition thereof At least one composition selected from the above is preferred. Examples thereof include compounds described in JP-A Nos. 2000-47004, 2001-315242, 2001-31871, and 2001-296401. A curable film obtained from a colloidal metal oxide obtained from a hydrolyzed condensate of metal alkoxide and a metal alkoxide composition is also preferred. For example, it describes in Unexamined-Japanese-Patent No. 2001-293818. The refractive index of the high refractive index layer is generally 1.70 to 2.20. The thickness of the high refractive index layer is preferably 5 nm to 10 μm, and more preferably 10 nm to 1 μm. The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.50 to 1.70.

(Low refractive index layer)
The low refractive index layer in the present invention is preferably formed from a fluorine-containing compound that is crosslinked by heat or ionizing radiation, inorganic or organic fine particles, a binder, and the like. A refractive index layer or the like can also be used. If the refractive index of the low refractive index layer is low, it is preferable because the antireflection performance is improved, but it is difficult from the viewpoint of imparting strength to the low refractive index layer. Considering this balance, the refractive index of the low refractive index layer is preferably 1.30 to 1.50, and more preferably 1.35 to 1.49. Further, the refractive index of the low refractive index layer needs to be lower in the range of 0.05 to 2.0 than that of the high refractive index layer. As a crosslinkable fluoropolymer compound used for the low refractive index layer, in addition to a perfluoroalkyl group-containing silane compound (for example, (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane), etc. Examples thereof include a fluorine-containing copolymer having a monomer and a monomer for imparting a crosslinkable group as structural units.

  The fluorine-containing polymer is preferably synthesized by a polymerization reaction of an ethylenically unsaturated monomer containing a fluorine atom. Specific examples of the fluorine-containing monomer include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.) , Partially or fully fluorinated alkyl ester derivatives of (meth) acrylic acid (for example, Biscoat 6FM (manufactured by Osaka Organic Chemicals) and M-2020 (manufactured by Daikin)), fully or partially fluorinated vinyl ethers, perfluoropolyether and And derivatives thereof. From these, one or a plurality of monomers can be combined at an arbitrary ratio, and the desired fluorine-containing polymer can be obtained by (co) polymerization. Moreover, you may use the copolymer of the said fluorine-containing monomer and the monomer which does not contain a fluorine atom as a fluorine-containing polymer. There are no particular limitations on the monomers that can be used in combination, such as olefins (ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.), acrylic esters (methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate), Methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.), styrene derivatives (styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.), vinyl ethers (methyl vinyl ether, etc.), Vinyl esters (vinyl acetate, vinyl propionate, vinyl cinnamate, etc.), acrylamides (N-tert-butylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides, acrylonitrile derivatives Mention may be made of the body or the like. As preferred fluorine compounds, paragraph numbers [0018] to [0026] of JP-A-9-222503, paragraph numbers [0019] to [0030] of JP-A-11-38202, paragraph number of JP-A-2001-40284. [0027] to [0028], Japanese Patent Application Laid-Open Nos. 2000-284102 and 2003-26732, paragraph numbers [0012] to [0077], and Japanese Patent Application Laid-Open No. 2004-45462, paragraph numbers [0030] to [0047]. ] Etc. can be mentioned. In addition, it is also preferable to introduce polyorganosiloxane in the fluoropolymer for imparting slipperiness. This can be obtained, for example, by polymerization of a polyorganosiloxane having an acrylic group, a methacryl group, a vinyl ether group, a styryl group or the like at the terminal and the above monomer.

  The monomer for imparting a crosslinkable group has a carboxyl group, a hydroxyl group, an amino group, a sulfonic acid group, etc. in addition to a (meth) acrylate monomer having a crosslinkable functional group in advance in the molecule like glycidyl methacrylate ( And (meth) acrylate monomers (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.). It is known from JP-A-10-25388 and JP-A-10-147739 that the latter can introduce a crosslinked structure after copolymerization. A commercially available material can also be used as the fluoropolymer. Examples of commercially available fluoropolymers include Cytop (Asahi Glass), Teflon AF (DuPont), polyvinylidene fluoride, Lumiflon (Asahi Glass), Opstar (JSR), and the like. The low refractive index layer made of a fluorine material preferably has a dynamic friction coefficient of 0.03 to 0.15 and a contact angle with water of 90 to 120 °.

  Use of inorganic fine particles in the low refractive index layer made of the above-mentioned fluorine material is preferable from the viewpoint of improving the strength. Amorphous particles are preferably used as the inorganic fine particles, and are preferably composed of oxides such as metals, nitrides, sulfides or halides, and oxides are particularly preferable. As atoms such as metals constituting these inorganic compounds, Na, K, Mg, Ca, Ba, Al, Zn, Fe, Cu, Ti, Sn, In, W, Y, Sb, Mn, Ga, V, Nb , Ta, Ag, Si, B, Bi, Mo, Ce, Cd, Be, Pb and Ni are preferable, and Mg, Ca, B and Si are more preferable. An inorganic compound containing two kinds of metals may be used. A particularly preferred inorganic compound is silicon dioxide, ie silica. The average particle size of the inorganic fine particles is preferably 0.001 to 0.2 μm, and more preferably 0.005 to 0.05 μm. The particle size of the fine particles is preferably as uniform as possible (monodispersed or substantially monodispersed). The amount of the inorganic fine particles added is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and particularly preferably 10 to 50% by mass based on the total mass of the low refractive index layer. The inorganic fine particles are preferably used after being subjected to a surface treatment. As the surface treatment method, there are a physical surface treatment such as plasma discharge treatment and corona discharge treatment and a chemical surface treatment using a coupling agent, and a chemical surface treatment using a coupling agent is preferable. As the coupling agent, an organoalkoxy metal compound (for example, a titanium coupling agent or a silane coupling agent) is preferably used. Silane coupling treatment is particularly effective when the inorganic fine particles are silica.

  As the low refractive index layer, it is also preferable to use a layer in which inorganic or organic fine particles are used and microvoids are formed between or within the fine particles. Microvoids between particles can be formed by stacking at least two fine particles. When spherical particles having the same particle size (completely monodispersed) are closely packed, microvoids between particles having a porosity of 26% by volume are formed. When spherical fine particles having the same particle size are filled by simple cubic, microvoids between fine particles having a porosity of 48% by volume are formed. In an actual low refractive index layer, the particle size distribution of the fine particles and the intra-particle microvoids exist, so the porosity varies considerably from the above theoretical value. By increasing the porosity, the refractive index of the low refractive index layer can be lowered. In addition, by stacking microparticles to form microvoids and adjusting the particle size of microparticles, the size of interparticle microvoids is also moderate (does not scatter light and does not cause problems with the strength of the low refractive index layer) Can be easily adjusted to the value. Furthermore, by making the particle size of the fine particles uniform, it is possible to obtain an optically uniform low refractive index layer in which the size of the microvoids between particles is uniform. As a result, the low refractive index layer is microscopically a microvoided porous film, but can be made optically or macroscopically uniform. The interparticle microvoids are preferably closed in the low refractive index layer by fine particles and a polymer. The closed air gap also has an advantage that light scattering on the surface of the low refractive index layer is less than that of an opening opened on the surface of the low refractive index layer. By forming the microvoids, the macroscopic refractive index of the low refractive index layer becomes lower than the sum of the refractive indexes of the components constituting the low refractive index layer. The refractive index of the layer is the sum of the refractive indices per volume of the layer components. The refractive index of the constituent component of the low refractive index layer such as fine particles or polymer is larger than 1, whereas the refractive index of air is 1.00. Therefore, a low refractive index layer having a very low refractive index can be obtained by forming microvoids.

  The average particle size of the fine particles is preferably 0.5 to 200 nm, more preferably 1 to 100 nm, still more preferably 3 to 70 nm, and most preferably in the range of 5 to 40 nm. The particle size of the fine particles is preferably as uniform (monodispersed) as possible. The inorganic fine particles are preferably oxides such as metals, nitrides, sulfides or halides, more preferably oxides or halides, and most preferably oxides or fluorides. As atoms such as metals constituting these inorganic compounds, Na, K, Mg, Ca, Ba, Al, Zn, Fe, Cu, Ti, Sn, In, W, Y, Sb, Mn, Ga, V, Nb , Ta, Ag, Si, B, Bi, Mo, Ce, Cd, Be, Pb and Ni are preferable, and Mg, Ca, B and Si are more preferable. The inorganic fine particles are preferably amorphous. An inorganic compound containing two kinds of metals may be used. A particularly preferred inorganic compound is silicon dioxide, ie silica.

  The microvoids in the inorganic fine particles can be formed, for example, by cross-linking silica molecules forming the particles. Crosslinking silica molecules reduces the volume and makes the particles porous. (Porous) inorganic fine particles having microvoids are prepared by a sol-gel method (described in JP-A Nos. 53-112732 and 57-9051) or a precipitation method (described in APPLIEDOPTICS, pages 27, 3356 (1988)). Can be directly synthesized as a dispersion. Further, the powder obtained by the drying / precipitation method can be mechanically pulverized to obtain a dispersion. Commercially available porous inorganic fine particles (for example, silicon dioxide sol) may be used. The inorganic fine particles having microvoids are preferably used in a state of being dispersed in an appropriate medium in order to form a low refractive index layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol) and ketone (for example, methyl ethyl ketone, methyl isobutyl ketone) are preferable.

  The organic fine particles are preferably polymer fine particles synthesized by polymerization reaction of monomers (for example, emulsion polymerization method). The organic fine particles are also preferably amorphous. The organic fine particle polymer preferably contains a fluorine atom. The proportion of fluorine atoms in the polymer is preferably 35 to 80% by mass, and more preferably 45 to 75% by mass. It is also preferable to form microvoids in the organic fine particles by, for example, cross-linking the polymer forming the particles and reducing the volume. In order to crosslink the polymer forming the particles, it is preferable to use 20 mol% or more of the monomer for synthesizing the polymer as a polyfunctional monomer. The ratio of the polyfunctional monomer is more preferably 30 to 80 mol%, and most preferably 35 to 50 mol%. Examples of the monomer used for the synthesis of the organic fine particles and the fluorine atom used for synthesizing the fluoropolymer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, Perfluoro-2,2-dimethyl-1,3-dioxole), fluorinated alkyl esters of acrylic acid or methacrylic acid and fluorinated vinyl ethers.

  A copolymer of a monomer containing a fluorine atom and a monomer not containing a fluorine atom may be used. Examples of monomers that do not contain fluorine atoms include olefins (eg, ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride), acrylic esters (eg, methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate). , Methacrylates (eg, methyl methacrylate, ethyl methacrylate, butyl methacrylate), styrenes (eg, styrene, vinyl toluene, α-methyl styrene), vinyl ethers (eg, methyl vinyl ether), vinyl esters ( For example, vinyl acetate, vinyl propionate), acrylamides (for example, N-tert-butylacrylamide, N-cyclohexylacrylamide), methacrylamides and acrylonitriles are included. Examples of polyfunctional monomers include dienes (eg, butadiene, pentadiene), esters of polyhydric alcohols and acrylic acid (eg, ethylene glycol diacrylate, 1,4-cyclohexane diacrylate, dipentaerythritol hexaacrylate), Esters of polyhydric alcohol and methacrylic acid (for example, ethylene glycol dimethacrylate, 1,2,4-cyclohexanetetramethacrylate, pentaerythritol tetramethacrylate), divinyl compounds (for example, divinylcyclohexane, 1,4-divinylbenzene), divinyl Sulfones, bisacrylamides (eg, methylene bisacrylamide) and bismethacrylamides are included.

  The low refractive index layer containing voids preferably contains a polymer in an amount of 5 to 50% by mass. The polymer has a function of adhering fine particles and maintaining the structure of a low refractive index layer including voids. The amount of the polymer used is adjusted so that the strength of the low refractive index layer can be maintained without filling the voids. The amount of the polymer is more preferably 10 to 30% by mass of the total amount of the low refractive index layer.

Adhering the polymer and the fine particles is preferable for imparting strength to the low refractive index layer. As the method,
(A) a method of binding a polymer to a surface treatment agent for fine particles,
(A) a method of forming a polymer shell around a fine particle as a core, and (c) a method of using a polymer as a binder between the fine particles,
Can be preferably mentioned.
The polymer to be bonded to the surface treatment agent (a) is preferably a shell polymer (a) or a binder polymer (c).
The polymer (a) is preferably formed around the fine particles by a polymerization reaction before preparing the coating solution for the low refractive index layer.
The above polymer (c) is preferably formed by adding a monomer to the coating solution for the low refractive index layer and polymerization reaction at the same time as or after coating the low refractive index layer. Of (a) to (c), it is preferable to carry out by combining two or three types, (a) and (c) two types, or (a) It is particularly preferred to carry out in combination.
The above method is described in detail in JP-A-11-6902.

Further, as a material for the low refractive index layer, a hydrolyzed partial condensate (so-called sol-gel film) of an organometallic compound such as organosilane is also preferable. Of these, the hydrolyzed partial condensate of organosisilane is preferably low in refractive index and strong in film strength, and more preferably is a hydrolyzed partial condensate of photocurable organosilane. Specific examples of organosilanes include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane. silane, phenyltrimethoxysilane, _{phenyltriethoxysilane, CF 3 CH 2 CH 2 Si} (OCH 3) 3, CF 3 (CF 2) 5 CH 2 CH 2 Si (OCH 3) 3, γ- glycidoxypropyltrimethoxysilane Trimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-trimethoxysilylpropyl isocyanate, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- Acryloxypropyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-aminopropylmethyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-methacryloxypropylmethyldimethoxy Although silane etc. are mentioned, the organosilane which can be used by this invention is not limited to these. In addition, two or more different organosilanes are usually used in a mixed manner, and it is preferable to adjust the hardness, brittleness, and functional group introduction appropriately.

  The hydrolytic condensation reaction of organosilane can be carried out in the absence of a solvent or in a solvent. The solvent is preferably an organic solvent, and examples thereof include acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, methanol, ethanol, isopropyl alcohol, butanol, toluene, xylene, tetrahydrofuran, 1,4-dioxane and the like. The hydrolysis condensation reaction is preferably carried out in the presence of a catalyst. Catalysts include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, organic acids such as oxalic acid, acetic acid, formic acid, methanesulfonic acid and toluenesulfonic acid, inorganic bases such as sodium hydroxide, potassium hydroxide and ammonia, triethylamine, Examples thereof include organic bases such as pyridine, metal alkoxides such as triisopropoxyaluminum and tetrabutoxyzirconium, metal chelate compounds of the metal alkoxides with ethyl acetoacetate, acetylacetone, and the like. In the hydrolysis condensation reaction, usually 0.3 to 2.0 mol, preferably 0.5 to 1.0 mol of water is added to 1 mol of the alkoxy group, and usually 25 to 25 mol in the presence of the solvent and the catalyst. It is carried out by stirring at 100 ° C. The addition amount of the catalyst is usually 0.01 to 10 mol%, preferably 0.1 to 5 mol% with respect to the alkoxy group. The reaction conditions are preferably adjusted as appropriate depending on the reactivity of the organosilane.

  When a hydrolyzate of organosilane and / or a partial condensate thereof, so-called sol-gel component (hereinafter referred to as such) is made photocurable, the sol-gel component contains a compound that generates a reaction accelerator by light. Specifically, a photoacid generator or a photobase generator is preferable, and any of them can promote the condensation reaction of the sol-gel component. Specific examples of photoacid generators include benzoin tosylate, tri (nitrobenzyl) phosphate, diaryliodonium salts, and triarylsulfonium salts. Photobase generators include nitrobenzylcyclohexylcarbamate and di (methoxybenzyl). Examples include hexamethylene dicarbamate. Among these, a photoacid generator is more preferable, and specifically, a triarylsulfonium salt and a diaryliodonium salt are preferable. Sensitizing dyes can also be preferably used in combination with these compounds. The amount of the compound that generates a reaction accelerator by light is preferably 0.1 to 15%, more preferably 0.5 to 5%, based on the total solid content of the low refractive index layer coating solution.

  In the low refractive index layer of the sol-gel component of the present invention, the aforementioned fluorine-containing polymer is preferably used in combination for the purpose of imparting antifouling properties and slipperiness. Among the fluorine-containing polymers, a polymer obtained by polymerizing a fluorine-containing vinyl monomer is preferable, and it is preferable that the polymer has a functional group capable of covalently bonding with the sol-gel component from the viewpoint of compatibility with the sol-gel component and film strength. The film thickness of the low refractive index layer is preferably 30 to 200 nm, more preferably 50 to 150 nm, and most preferably 60 to 120 nm.

(Hard coat layer)
The hard coat layer is provided on the surface of the transparent support (cellulose ester film) in order to impart physical strength to the antireflection film. In particular, it is preferably provided between the transparent support and the high refractive index layer. The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of a light and / or heat curable compound. The curable functional group is preferably a photopolymerizable functional group, and the hydrous functional group-containing organometallic compound is preferably an organic alkoxysilyl compound. Specific examples of these compounds are the same as those exemplified for the high refractive index layer. Specific examples of the constituent composition of the hard coat layer include those described in JP-A Nos. 2002-144913, 2000-9908, and WO 00/46617. The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form fine particles dispersed in the hard coat layer using the method described for the high refractive index layer. The hard coat layer can also serve as an antiglare layer (described later) provided with particles having an average particle size of 0.2 to 10 μm to provide an antiglare function (antiglare function). The film thickness of the hard coat layer can be appropriately designed depending on the application. The film thickness of the hard coat layer is preferably 0.2 to 10 μm, more preferably 0.5 to 7 μm. The strength of the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher in a pencil hardness test according to JIS K5400. Further, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

(Light diffusive or anti-glare hard coat layer)
The hard coat layer is composed of translucent particles for imparting antiglare properties and / or light diffusibility (internal scattering), high refractive index inorganic ultrafine particles, and a matrix for sufficiently strengthening the hard coat properties. Contains at least one each.

  The antiglare or internal scattering hard coat layer is a refractive index nonuniform layer in which translucent particles having an average particle size of 0.3 to 10 μm are dispersed in a matrix. The components other than the above particles forming the antiglare or internal scattering hard coat layer, that is, the refractive index of the matrix in which high-refractive-index inorganic ultrafine particles having a particle size of 100 nm or less, which will be described later, are dispersed, are 1.57 to 2.00. It is preferable that there is, more preferably 1.60 to 1.80, which is a high refractive index. Within this range, the antireflection performance is sufficient as an antireflection film, which is preferable.

  The anti-glare or internal scattering hard coat layer has an internal scattering effect due to the light-transmitting particles having a particle size of 0.3 to 10 μm dispersed in the matrix in which the high refractive index inorganic ultrafine particles are dispersed. There is no influence of optical interference on the dazzling hard coat layer. In the high refractive index antiglare or internal scattering hard coat layer having no translucent particles of the above particle size, optical interference due to the difference in refractive index between the antiglare or internal scattering hard coat layer and the support. In addition, a large amplitude of the reflectance is seen in the wavelength dependency of the reflectance, and as a result, the antireflection effect is deteriorated and color unevenness is generated at the same time.

  As described above, the translucent particles have an average particle size of 0.3 for the purpose of providing antiglare properties and internal scattering properties and preventing deterioration of reflectance due to interference with the transparent support or the hard coat layer, and preventing color unevenness. Transparent particles of 10 μm are preferred. More preferably, it is 1.0-7.0 micrometers, More preferably, it is the range of 1.5-4.0.

The narrower the particle size distribution of the particles, the better. The S value indicating the particle size distribution of the particles is represented by the following formula, preferably 2 or less, more preferably 1.0 or less, and particularly preferably 0.7 or less.
S = [D (0.9) -D (0.1)] / D (0.5)
D (0.1): Particle size equivalent to 10% of the integrated value of the volume converted particle size D (0.5): Particle size equivalent to 50% of the integrated value of the volume converted particle size D (0.9): Volume converted particle Particle size equivalent to 90% of the integrated size

As the shape of the translucent particles, either a true sphere or an indefinite shape can be used. Moreover, you may use together and use 2 or more types of translucent particle | grains from which a shape differs. Moreover, it is preferable that the translucent particles having a particle size smaller than the matrix layer thickness of the antiglare or internal scattering layer is less than 50% of the entire translucent particles. The particle size distribution can be measured by the Coulter counter method, but the distribution is converted to a particle number distribution. The translucent particles are antiglare or internal scattering so that the amount of particles in the formed antiglare hard coat layer is preferably 10 to 1000 mg / m ² , more preferably 30 to 800 mg / m ² . It is contained in the hard coat layer.

  Furthermore, as another preferred embodiment, an antiglare or internal scattering hard coat layer using at least two or more kinds of translucent particles having different particle sizes can be mentioned. The translucent particles are not limited as long as the following requirements are satisfied, regardless of whether the material types are the same or the same.

Examples of the translucent particles include inorganic particles and organic particles. Specific examples of the inorganic particles include silicon dioxide, zirconium oxide, aluminum oxide, tin oxide, ITO (In ₂ O ₃ doped with SnO ₂ ), zinc oxide, titanium oxide containing a specific metal (cobalt, aluminum as a specific metal) And zirconium)), and particles of calcium carbonate, barium sulfate, talc, kaolin, calcium sulfate, and the like. Of these, silicon dioxide and aluminum oxide are preferred.

  The organic particles are preferably resin particles. Examples of the resin particles include silicone resin, polyester resin, polyurethane resin, polyimide resin, melamine resin, benzoguanamine resin, (meth) acrylate resin, polystyrene resin, polyvinyl ether resin, (meth) acrylonitrile resin, (meth). Examples thereof include particles such as acrylamide-based resins and polyvinylidene fluoride resins. Preferably, crosslinked resin particles such as a melamine resin, a benzoguanamine resin, a (meth) acrylate resin, and a polystyrene resin are used. In particular, crosslinked resin fine particles composed of a polymer obtained by emulsion polymerization of a polymerizable monomer and a crosslinking agent, soap-free polymerization, suspension polymerization, seed polymerization, two-stage swelling polymerization, dispersion polymerization, or the like can be suitably used.

Specific examples of the translucent particles include silica particles (for example, Nippon Shokubai Co., Ltd. Seahosta series, refractive index = 1.43), alumina particles (for example, Sumitomo Chemical Co., Ltd. Sumiko Random series, refraction) Rate = 1.64), particles of inorganic compounds such as TiO ₂ particles, or crosslinked acrylic particles (for example, MX series manufactured by Soken Chemical Co., Ltd., refractive index = 1.49), crosslinked styrene particles (for example, Soken Chemical Co., Ltd.) SX series manufactured, refractive index = 1.61), crosslinked melamine particles, crosslinked benzoguanamine particles (for example, Nippon Shokubai Co., Ltd. Eposter series, refractive index = 1.68) and the like. As the shape of the translucent particle, either a true sphere or an indefinite shape can be used, but a spherical particle having a uniform surface protrusion shape is preferable.

(Forward scattering layer)
When applied to a liquid crystal display device, the forward scattering layer is provided to provide an effect of improving the viewing angle when the viewing angle is inclined in the vertical and horizontal directions. By dispersing fine particles having different refractive indexes in the hard coat layer, it can also serve as a hard coat function. For example, Japanese Patent Application Laid-Open No. 11-38208 specifying a forward scattering coefficient, Japanese Patent Application Laid-Open No. 2000-199809 having a relative refractive index of a transparent resin and fine particles in a specific range, and Japanese Patent Application Laid-Open No. 2002 specifying a haze value of 40% or more. -107512 gazette etc. are mentioned.

(Other layers)
The antireflection film of the present invention may further be provided with a primer layer, a moisture proof layer, an undercoat layer, a protective layer, a shield layer, and a sliding layer. The shield layer is provided to shield electromagnetic waves and infrared rays.

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

(6) Application of optical compensation layer (production of optical compensation film)
The optically anisotropic layer is for compensating the liquid crystal compound in the liquid crystal cell in the black display of the liquid crystal display device. It is formed by forming an optically anisotropic layer.

(Alignment film)
The unstretched or stretched cellulose ester film constituting the laminate of the present invention is surface-treated as described above, and an alignment film is further provided thereon. This film has a function of defining the alignment direction of liquid crystalline molecules. However, if the alignment state is fixed after the alignment of the liquid crystalline compound, the alignment film plays the role, and thus is not necessarily an essential component of the optical compensation film of the present invention. That is, it is possible to produce the polarizing plate of the present invention by transferring only the optically anisotropic layer on the alignment film in which the alignment state is fixed onto the polarizer. The alignment film is an organic compound (for example, ω-tricosanoic acid) formed by rubbing treatment of an organic compound (preferably a polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodget method (LB film). , Dioctadecylmethylammonium chloride, methyl stearylate). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known. The alignment film is preferably formed by polymer rubbing treatment. In principle, the polymer used for the alignment film has a molecular structure having a function of aligning liquid crystal molecules. In the present invention, in addition to the function of aligning liquid crystalline molecules, a crosslink having a function of aligning a side chain having a crosslinkable functional group (for example, a double bond) to the main chain or aligning liquid crystalline molecules. It is preferable to introduce a functional functional group into the side chain.

  As the polymer used for the alignment film, either a polymer that can be crosslinked by itself or a polymer that is crosslinked by a crosslinking agent can be used, and a plurality of combinations thereof can be used. Examples of the polymer include methacrylate copolymers, styrene copolymers, polyolefins, polyvinyl alcohol and modified polyvinyl alcohol, poly (N-methylol) described in paragraph No. [0022] of JP-A-8-338913. Acrylamide), polyester, polyimide, vinyl acetate copolymer, carboxymethylcellulose, polycarbonate and the like. Silane coupling agents can be used as the polymer. Water-soluble polymers (for example, poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol) are preferable, gelatin, polyvinyl alcohol, and modified polyvinyl alcohol are more preferable, and polyvinyl alcohol and modified polyvinyl alcohol are most preferable. . It is particularly preferable to use two types of polyvinyl alcohol or modified polyvinyl alcohol having different degrees of polymerization. The saponification degree of polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%. It is preferable that the polymerization degree of polyvinyl alcohol is 100-5000.

  A side chain having a function of aligning liquid crystal molecules generally has a hydrophobic group as a functional group. The specific type of functional group is determined according to the type of liquid crystal molecule and the required alignment state. For example, the modifying group of the modified polyvinyl alcohol can be introduced by copolymerization modification, chain transfer modification or block polymerization modification. Examples of modifying groups include hydrophilic groups (carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, amino groups, ammonium groups, amide groups, thiol groups, etc.), hydrocarbon groups having 10 to 100 carbon atoms, fluorine atoms Substituted hydrocarbon groups, thioether groups, polymerizable groups (unsaturated polymerizable groups, epoxy groups, azirinidyl groups, etc.), alkoxysilyl groups (trialkoxy, dialkoxy, monoalkoxy) and the like can be mentioned. As specific examples of these modified polyvinyl alcohol compounds, for example, paragraph numbers [0022] to [0145] in JP-A No. 2000-155216 and paragraph numbers [0018] to [0018] in JP-A No. 2002-62426 are described. [0022] and the like.

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

  The crosslinkable functional group of the alignment film polymer preferably contains a polymerizable group in the same manner as the polyfunctional monomer. Specific examples include those described in paragraphs [0080] to [0100] in JP-A-2000-155216. Apart from the crosslinkable functional group, the alignment film polymer can also be crosslinked using a crosslinking agent. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole, and dialdehyde starch. Two or more kinds of crosslinking agents may be used in combination. Specific examples include compounds described in paragraphs [0023] to [0024] in JP-A-2002-62426. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred. 0.1-20 mass% is preferable with respect to a polymer, and, as for the addition amount of a crosslinking agent, 0.5-15 mass% is more preferable. The amount of the unreacted crosslinking agent remaining in the alignment film is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. By adjusting in this way, even if the alignment film is used for a long time in a liquid crystal display device or left in a high-temperature and high-humidity atmosphere for a long time, sufficient durability without occurrence of reticulation can be obtained.

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

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

The alignment film is provided on the stretched / unstretched cellulose ester film or on the undercoat layer. The alignment film can be obtained by rubbing the surface after crosslinking the polymer layer as described above. For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of a liquid crystal display device can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are planted on average. When industrially implemented, this is achieved by bringing a rotating rubbing roll into contact with the film with the polarizing film being transported. However, the roundness, cylindricity, and deflection (eccentricity) of the rubbing roll can Is preferably 30 μm or less. The film wrap angle on the rubbing roll is preferably 0.1 to 90 °. However, as described in JP-A-8-160430, a stable rubbing treatment can be obtained by winding 360 ° or more. As for the conveyance speed of a film, 1-100 m / min is preferable. It is preferable to select an appropriate rubbing angle in the range of 0 to 60 °. When used for a liquid crystal display device, 40 to 50 ° is preferable. 45 ° is particularly preferred.
The thickness of the alignment film thus obtained is preferably in the range of 0.1 to 10 μm.

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

(Rod-like liquid crystalline molecules)
Examples of rod-like liquid crystalline molecules include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. The rod-like liquid crystalline molecule includes a metal complex. In addition, a liquid crystal polymer containing a rod-like liquid crystalline molecule in a repeating unit can also be used as the rod-like liquid crystalline molecule. In other words, the rod-like liquid crystal molecule may be bonded to a (liquid crystal) polymer.

  For rod-like liquid crystalline molecules, see Chapter 4, Chapter 7 and Chapter 11 of the Chemistry of the Quarterly Chemistry Vol. 22 (1994) The Chemical Society of Japan, and the 142th Committee of the Japan Society for the Promotion of Science. Described in Chapter 3. The birefringence of the rod-like liquid crystal molecule is preferably in the range of 0.001 to 0.7. The rod-like liquid crystalline molecule preferably has a polymerizable group in order to fix its alignment state. The polymerizable group is preferably a radically polymerizable unsaturated group or a cationically polymerizable group. Specifically, for example, polymerization described in paragraphs [0064] to [0086] of JP-A-2002-62427 is described. And a polymerizable liquid crystal compound.

(Discotic liquid crystalline molecules)
For discotic liquid crystal molecules, C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), azacrown type and phenylacetylene type macrocycles are included.

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

  In order to fix the discotic liquid crystalline molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline molecules. A compound in which the discotic core and the polymerizable group are bonded via a linking group is preferable, whereby the orientation state can be maintained even in the polymerization reaction. Examples thereof include compounds described in paragraph numbers [0151] to [0168] in JP-A 2000-155216. In the hybrid alignment, the angle between the major axis (disk surface) of the discotic liquid crystalline molecule and the surface of the polarizing film increases or decreases in the depth direction of the optically anisotropic layer and with increasing distance from the surface of the polarizing film. doing. The angle preferably decreases with increasing distance. Further, the change in angle can be a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, or an intermittent change including an increase and a decrease. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction. Even if the angle includes a region where the angle does not change, the angle only needs to increase or decrease as a whole. Furthermore, it is preferable that the angle changes continuously.

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

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

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

  Examples of the surfactant include conventionally known compounds, and fluorine compounds are particularly preferable. Specific examples include the compounds described in paragraph numbers [0028] to [0056] in JP-A-2001-330725.

  The polymer used together with the discotic liquid crystalline molecules is preferably capable of changing the tilt angle of the discotic liquid crystalline molecules. A cellulose ester can be mentioned as an example of the polymer. Preferable examples of the cellulose ester include those described in paragraph [0178] of JP-A No. 2000-155216. The addition amount of the polymer is preferably in the range of 0.1 to 10% by mass, and preferably in the range of 0.1 to 8% by mass with respect to the liquid crystal molecule so as not to disturb the alignment of the liquid crystal molecules. It is more preferable. The discotic nematic liquid crystal phase-solid phase transition temperature of the discotic liquid crystalline molecules is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.

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

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

(Fixing the alignment state of liquid crystalline molecules)
The aligned liquid crystalline molecules can be fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (US Pat. No. 2,448,828). Description), α-hydrocarbon-substituted aromatic acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (US Pat. Nos. 3,046,127 and 2,951,758). In each specification), a combination of triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3,549,367), acridine and phenazine compound (Japanese Patent Laid-Open No. 60-105667), U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970). As for the usage-amount of a photoinitiator, it is preferable that the coating liquid solid content exists in the range of 0.01-20 mass%, and it is more preferable that it exists in the range of 0.5-5 mass%.

It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules. The irradiation energy is preferably in the range of ^{20mJ / cm 2 ~50J / cm 2} , more preferably in the range of ^{20mJ / cm 2 ~5000mJ / cm 2} , a range of 100mJ / cm ² ~800mJ / cm ² More preferably. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.

  It is also preferable to combine this optical compensation film and a polarizing film. Specifically, the optically anisotropic layer is formed by applying the coating liquid for the optically anisotropic layer as described above to the surface of the polarizing film. As a result, without using a polymer film between the polarizing film and the optically anisotropic layer, a thin polarizing plate having a small stress (strain × cross-sectional area × elastic modulus) associated with the dimensional change of the polarizing film is produced. . When the polarizing plate according to the present invention is attached to a large liquid crystal display device, an image with high display quality can be displayed without causing problems such as light leakage. The tilt angle between the polarizing film and the optical compensation layer is stretched so as to match the angle formed between the transmission axis of the two polarizing plates bonded to both sides of the liquid crystal cell constituting the liquid crystal display device and the vertical or horizontal direction of the liquid crystal cell. It is preferable to do. A normal inclination angle is 45 °. However, recently, transmissive, reflective, and transflective liquid crystal display devices have been developed that are not necessarily 45 °, and it is preferable that the stretching direction can be arbitrarily adjusted in accordance with the design of the liquid crystal display device.

[Use for liquid crystal display]
The liquid crystal display device of the present invention is formed using the cellulose ester film constituting the laminate of the present invention. Specifically, it is formed using at least one selected from the group consisting of the above polarizing plate, optical compensation film, and antireflection film.

(General liquid crystal display device configuration)
The cellulose ester film constituting the laminate of the present invention is particularly effective when used as an optical compensation sheet for liquid crystal display devices. When the film itself is used as an optical compensation sheet, it is preferable to arrange the transmission axis of a polarizing element (described later) and the slow axis of the optical compensation sheet made of a cellulose ester film so as to be substantially parallel or perpendicular. . Such an arrangement of the polarizing element and the optical compensation sheet is described in JP-A-10-48420. The liquid crystal display device includes a liquid crystal cell having a liquid crystal supported between two electrode substrates, two polarizing elements disposed on both sides thereof, and at least one sheet between the liquid crystal cell and the polarizing element. An optical compensation sheet is arranged.

  The liquid crystal layer of the liquid crystal cell is usually formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive substance. The liquid crystal cell may further be provided with a gas barrier layer, a hard coat layer, or an undercoat layer (used for adhesion of the transparent electrode layer). These layers are usually provided on the substrate. The substrate of the liquid crystal cell generally has a thickness of 80 μm to 500 μm. The optical compensation sheet is a birefringent film for removing the coloration of the liquid crystal screen. In the present invention, the cellulose ester film itself can be used as an optical compensation sheet. Further, the function may be imparted as an antireflection layer, an antiglare layer, a λ / 4 layer or a biaxially stretched cellulose ester film. In addition, in order to improve the viewing angle of the liquid crystal display device, the cellulose ester film laminate constituting the laminate of the present invention and a film exhibiting birefringence (positive / negative relationship) opposite to that are overlapped for optical compensation It may be used as a sheet. The range of the thickness of the optical compensation sheet is the same as the preferable thickness of the cellulose ester film constituting the laminate of the present invention described above.

  Examples of the polarizing film of the polarizing element include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. Any polarizing film is generally manufactured using a polyvinyl alcohol film. The protective film of the polarizing plate preferably has a thickness of 25 μm to 350 μm, and more preferably has a thickness of 40 μm to 200 μm. The liquid crystal display device may be provided with a surface treatment film. The functions of the surface treatment film include hard coat, anti-fogging treatment, anti-glare treatment and antireflection treatment. As described above, there has also been proposed an optical compensation sheet in which an optically anisotropic layer containing a liquid crystal (particularly a discotic liquid crystalline molecule) is provided on a support (Japanese Patent Application Laid-Open Nos. 3-9325 and 6-148429). Nos. 8-50206 and 9-26572). The cellulose ester film constituting the laminate of the present invention can also be used as a support for such an optical compensation sheet.

  The optically anisotropic layer is preferably a layer containing discotic liquid crystal molecules that are tilted and aligned. The angle formed by the disc surface of the discotic liquid crystal molecule and the support surface is preferably changed (hybrid alignment) in the depth direction of the optically anisotropic layer. The optical axis of the discotic liquid crystalline molecule exists in the normal direction of the disk surface. The discotic liquid crystalline molecule has birefringence in which the refractive index in the disc surface direction is larger than the refractive index in the normal direction of the disc surface. The discotic liquid crystalline molecules may be aligned substantially horizontally with respect to the support surface.

(VA type liquid crystal display device)
The cellulose ester film constituting the laminate of the present invention is also effectively used as a support for an optical compensation sheet of a VA liquid crystal display device having a VA mode liquid crystal cell. In the optical compensation sheet used for the VA 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 sheet or in the normal direction. The optical properties of the optical compensation sheet used in the VA liquid crystal display device are determined by the optical properties of the optically anisotropic layer, the optical properties of the support, and the arrangement of the optically anisotropic layer and the support. .

(OCB type liquid crystal display device and HAN type liquid crystal display device)
The cellulose ester film constituting the laminate of the present invention is also advantageously used as a support for an optical compensation sheet 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. It is done. In the optical compensation sheet 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 sheet or in the normal direction. The optical properties of the optical compensation sheet used in the OCB type liquid crystal display device or the HAN type liquid crystal display device are also 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 What is necessary is just to provide the optical characteristic corresponding to the liquid crystal cell of various OCB modes to the cellulose-ester film which comprises the laminated body of this invention. The range is that Re is 20 nm to 100 nm, preferably Re is 30 nm to 80 nm, and particularly 30 nm to 60 nm. Further, Rth is 150 nm to 300 nm, preferably Rth is 160 nm to 260 nm, and particularly 170 nm to 250 nm.

(Other liquid crystal display devices)
The cellulose ester film constituting the laminate of the present invention is also advantageously used as a support for an optical compensation sheet of an ASM type liquid crystal display device having an ASM (Axially Symmetric Alligned Microcell) mode liquid crystal cell. 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 a paper by Kume et al. (Kume et al., SID 98 Digest 1089 (1998)). The cellulose ester film constituting the laminate of the present invention may be used as a support for an optical compensation sheet of a TN type liquid crystal display device having a TN mode liquid crystal cell. TN mode liquid crystal cells and TN type liquid crystal display devices have been well known for a long time. The optical compensation sheet used for the TN liquid crystal display device is described in JP-A-3-9325, JP-A-6-148429, JP-A-8-50206, and JP-A-9-26572. The cellulose ester film constituting the laminate of the present invention may be imparted with preferable optical characteristics for an optical compensation sheet for these various liquid crystal display devices.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Example 1]
(1-1) Formation of cellulose ester film as substrate of cellulose ester film laminate (1) Preparation of cellulose ester pellet As cellulose ester, cellulose ester A (acetyl group substitution degree 1.50, propionyl group substitution degree) 1.40, total substitution degree 2.90, viscosity average degree of polymerization 180, water content 0.1% by weight, viscosity of 6% by weight in dichloromethane solution 140 mPa · s, average particle size 1.4 mm with standard deviation 0.8. 4 mm powder) was used. Cellulose ester A has a residual acetic acid content of 0.05 mass%, a residual propionic acid content of 0.03 mass%, a Ca content of 51 ppm, an Mg content of 15 ppm, and an Fe content of 0.45 ppm. Furthermore, the amount of sulfur as a sulfate group was 0.16 ppm.

  Further, the substitution degree of the acetyl group with respect to the hydroxyl group at the 6-position was 0.44, the substitution degree of the propionyl group with respect to the hydroxyl group at the 6-position was 0.53, and the mass average molecular weight / number average molecular weight ratio was 3.0. Cellulose ester A was formed into a solution on a glass plate using methylene chloride / methanol = 90/10 (mass ratio) to obtain a film having a thickness of 80 μm. The film consisting only of cellulose ester A had a yellow index of 0.87, a haze of 0.1, a transparency of 94.2%, and a Tg (glass transition temperature; measured by DSC) of 125 ° C. This cellulose ester A was synthesized using cellulose collected from a cotton linter as a raw material.

  This cellulose ester A was dried at 105 ° C. for 5 hours to adjust the water content to 0.07% by mass, and then, based on the cellulose ester solid content, 0.007% by mass of silica fine particles having a primary average particle size of 20 nm were absorbed by ultraviolet rays. 0.4% by mass of UV agent a {2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine} as an agent , UV agent b {2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole} 0.4% by weight, and UV agent c {2 (2′-hydroxy -3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole} is 0.4% by mass, the plasticizer biphenyldiphenyl phosphate is 2% by mass, bis (2,6- -Tert-butyl-4-methylphenyl) pentaerythritol di-phosphite, 0.1% by weight, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- [ (2H-benzotriazol-2-yl) phenol]] 0.1% by weight and bis [(1,2,2,6,6-pentamethyl-4-piperidinyl) 2- (3,5-di-tert -Butyl-4-hydroxybenzyl) -2-n-butylmalonate 0.1% by mass, tridecafluoroethyl methacrylate / poly (average polymerization degree 5) oxyethylene methacrylate / butyl acrylate = 30/20 as a release agent / 50 (molar ratio, molecular weight 9000) is added by 0.1% by mass, and 1,4-bis (2,4,6-tripropylcyclohexylsulfonamide) is further used as a dye. 0.00005% by weight of phenyl) anthraquinone was added.

  These were mixed and put into a hopper of a twin-screw kneading extruder, and further kneaded and melted at 150 to 200 ° C. with a screw rotation speed of 300 rpm and a residence time of 40 seconds. Furthermore, after extruding from a die at 200 kg / hour in a strand shape with a diameter of 3 mm in a 50 ° C. water bath and soaking for 1 minute (strand solidification), the temperature was lowered by passing water at 10 ° C. for 30 seconds to a length of 5 mm The pellet was obtained by cutting. The obtained pellets made of cellulose ester A were dried at 105 ° C. for 120 minutes, and then stored in a moisture-proof bag made of a laminate film having aluminum.

(2) Filtration The cellulose ester formed into a cylindrical pellet having a diameter of 3 mm and a length of 5 mm was dried with a vacuum dryer at 110 ° C. for 3 hours. This was put into a hopper and melted at 225 ° C., followed by pressure filtration at a rate of 0.1 m / min at 10 MPa using a sintered metal filter having a diameter of 5 μm. The obtained filtrate was confirmed to have a transparent and homogeneous composition.

(3) Melt film formation Next, it was put into a hopper adjusted to 105 ° C., and the melt was melt extruded over 10 minutes. At this time, the upstream melting temperature is 195 ° C., the intermediate melting temperature is 210 ° C., the downstream melting temperature is 225 ° C., the compression ratio is 14, the T-die temperature is 118 ° C., the distance between the T-die and the casting drum is 8 cm, Solidification rate is 30 ° C / sec, casting drum temperature is 115 ° C for the first roll (upstream), 114 ° C for the second roll (upstream), 113 ° C for the third roll (upstream), and cooling rate is -15 ° C / sec. Met. At this time, each level electrostatic application method (a 10 kV wire was placed 10 cm from the point where the melt was attached to the casting drum) was used. The solidified melt was peeled off, and conveyed through a nip roll at a winding tension of 6 kg / cm ² at 30 m / min to produce a long film (cellulose ester film sample 1-1). The film thickness was 80 μm, the width was 1.35 m, and the length was 900 m. In addition, after trimming both ends (each 3% of full width) just before winding, the protective film mentioned later was adhered to the casting roller surface side, and it wound up in the roll state. In addition, each process was implemented in the environmental condition which was made into the class 100 or less by the downflow type clean air.

(1-2) Adhesion of protective film As protective film A, a PET protective tape (product number: S-362, Fujimori Kogyo Co., Ltd.) in which the base material is a PET film (25 μm thickness) and the adhesive layer is an acrylic adhesive (20 μm thickness). Made, width 1.35 m, length 1000 m). Using the nip roll by the combination of the rubber roll and the metal roll for the protective film A on one side (casting roll surface side) of the cellulose ester film sample 1-1 produced above, the casting roll surface side of the cellulose ester film and the protective film A Was brought into a Y-shape, sandwiched between the nip rolls in a state where both of them were partially along, and bonded (laminated) by bonding. The average thickness of the cellulose ester film laminate (laminated sample 1-2) of the cellulose ester film and the protective film A was 105 μm. The thickness variation in the width direction and the longitudinal direction of the laminate was measured and found to be 2.5 μm and 1.0 μm, respectively. In addition, this process was implemented under the environmental conditions of class 1000 or less under downflow type clean air.

(1-3) Evaluation of Cellulose Ester Film Laminate The film wound around the roll core of the cellulose ester film laminate (laminate 1-2) obtained by the method described above is again pulled at a speed of 30 m / min. The protective film was peeled off. In addition, this process was implemented by the environmental condition which was made into the class 1000 or less by the downflow type clean air. The protective film was peeled off by winding the protective film around a winding core along the conveyance path of the laminate sample 1-2. The cellulose ester film obtained by peeling off the protective film was sandwiched between two orthogonal polarizing films, and when light leakage caused by scratches and foreign matters observed visually was observed, no light leakage was observed visually. It was confirmed that the film had an excellent surface shape.

  Here, it confirmed that the cellulose-ester film sample 1-1 obtained by peeling from the cellulose-ester film laminated body of this invention showed the following characteristics, and was an excellent optical substrate. The die streak was A, the damp unevenness was A, the Re unevenness was 0.2 nm, the Rth unevenness was 1.5 nm, the thickness unevenness was 2.1 μm, and the roll stain was A. It was also confirmed that the Re humidity dependency was as small as 1.4 nm and the Rth humidity dependency was as small as 5.8 nm.

In addition, the cellulose ester film sample 1-1 has an inclination width of 19.1 nm, a limit wavelength of 389.4 nm, an absorption edge of 376.5 nm and an absorption of 380 nm of 1.4%, and an axis deviation (molecular alignment axis) is The elastic modulus is 2.96 GPa in the longitudinal direction and 2.83 GPa in the width direction, the tensile strength is 115 MPa in the longitudinal direction, 107 MPa in the width direction, and the elongation is 61% in the longitudinal direction and 60% in the width direction. The alkali hydrolyzability was A, the curl value was −0.1 at a relative humidity of 25%, and 1.2 when wet (relative humidity of 10% or less). The moisture content was 1.8% by mass, and the thermal shrinkage was −0.05% in the longitudinal direction and −0.07% in the width direction. The foreign matter had less than 4 lint / m. As for the bright spot, 0.02 mm or less was less than 7/3 m, 0.02-0.05 mm was less than 3/3 m, and 0.05 mm or more was not found. These had excellent properties for optical applications. Moreover, the adhesiveness after application | coating is A, and it shows that moisture permeability is also favorable (650 g / m < ² > * day). Residual solvent was not detected.

(1-4) Measuring method and evaluation method It describes below about the measuring method and evaluation method of each said characteristic regarding the cellulose-ester film which is a board | substrate of a cellulose-ester film laminated body.
(Daisy)
In the evaluation of the die streak, streaky unevenness seen in the casting direction was visually observed under a reflection light source and evaluated according to the following.
A: Dice lines were not seen.
B: Dice lines were slightly seen.
C: Dice lines were clearly recognized.
D: It was recognized that die lines were remarkably generated on the entire surface.

(Danmura)
For the evaluation of danmura, stepwise irregularities seen in the width direction were visually observed under a reflected light source and evaluated according to the following.
A: Danmura was not seen.
B: Danmura was slightly observed.
C: Danmura was clearly recognized.
D: It was recognized that danmura was remarkably generated on the entire surface.

(Re and Rth)
After the cellulose ester film was conditioned for 24 hours at 25 ° C. and 60% relative humidity, the film was measured at 25 ° C. and 60% relative humidity using an automatic birefringence meter (KOBRA-21ADH: manufactured by Oji Scientific Instruments). In-plane retardation is measured by measuring the phase difference value at a wavelength of 590 nm from the direction normal to the surface and the tilt direction in increments of 10 ° from + 50 ° to −50 ° from the film normal with the slow axis as the rotation axis. The value (Re) and the retardation value (Rth) in the film thickness direction were calculated. Unless otherwise specified, Re and Rth refer to this value.

(Re unevenness, Rth unevenness)
100 points and 1 cm square were sampled at 1 m intervals in the longitudinal direction, and samples were sampled at 5 cm equal intervals over the entire width of the film. The difference between the maximum value and the minimum value of each sample obtained was determined and used as Re unevenness and Rth unevenness.

(Thickness unevenness)
100 points and 1 cm square were sampled at 1 m intervals in the longitudinal direction, and samples were sampled at 5 cm equal intervals over the entire width of the film. The thickness of each obtained sample was measured, and the difference between the maximum value and the minimum value of the thickness was determined and evaluated.

(Re humidity dependence and Rth humidity dependence)
Furthermore, Re (10% RH) and Rth (10% RH) were determined for these samples at 25 ° C./relative humidity 10%. Furthermore, these samples were similarly measured at 25 ° C. and a relative humidity of 80%, and Re (80% RH) and Rth (80% RH) were obtained. For each sample, the difference between Re (10% RH) and Re (80% RH) was determined to evaluate the dependency on Re humidity, and the difference between Rth (10% RH) and Rth (80% RH) was determined. Rth humidity dependency was evaluated.

(Haze)
The sample 40 mm × 80 mm was measured according to JIS K-6714 using a haze meter (HGM-2DP, Suga Test Instruments) at 25 ° C. and a relative humidity of 60%.

(Transparency)
The transparency of visible light (615 nm) was measured for a sample of 20 mm × 70 mm at 25 ° C. and a relative humidity of 60% using a transparency measuring device (AKA photoelectric tube colorimeter, KOTAKI Corporation).

(Molecular orientation axis)
The phase difference when a 70 mm × 100 mm sample was conditioned at 25 ° C. and 65% relative humidity for 2 hours and the incident angle at normal incidence was changed using an automatic birefringence meter (KOBRA21DH, Oji Scientific Co., Ltd.) The molecular orientation axis was calculated by measurement.

(Kisimi)
Samples 100 mm × 200 mm and 75 mm × 100 mm were conditioned at 23 ° C. and 65% relative humidity for 2 hours, and a large film was placed on the table using a Tensilon tensile tester (RTA-100, Orientec Co., Ltd.). A small film with a 200 g weight was fixed. We pulled the weight horizontally and measured the force when moving and the force when moving. Then, the static friction coefficient and the dynamic friction coefficient were calculated according to the following equations, respectively.
F = μ × W (W: weight of weight (kgf))

(Dynamic friction (steel ball method))
A 35mm x 100mm sample was conditioned for 2 hours at 23 ° C and 65% relative humidity. Using a dynamic friction coefficient measuring instrument (Toyo Baldwin), the sample was fixed on the table with the measurement surface facing up, and the steel ball was placed on the sample. Grated and measured the feed.

(Curl value)
A 35mm x 3mm sample was conditioned for 24 hours at 25%, 55% and 85% relative humidity in a curl humidity chamber (HEIDON (No. YG53-168), Shinto Kagaku Co., Ltd.), and the curvature radius was curled. The dry curl value was measured with In addition, curling with wet was measured after standing for 30 minutes in water having a water temperature of 25 ° C.

(Moisture permeability coefficient)
Sample 70 mmφ was conditioned at 25 ° C./95% relative humidity and 40 ° C./95% relative humidity for 24 hours, respectively, with a moisture permeation tester (KK-70907, Toyo Seiki Co., Ltd.) according to JIS Z-0208. The amount of water (g / m ² ) per unit area was calculated. And moisture permeability was calculated | required by (mass after humidity control)-(mass before humidity control). Further, as a compulsory evaluation, the moisture permeability was measured after conditioning for 24 hours at 60 ° C. and 95% relative humidity.

(Foreign substance inspection)
Reflected light was applied to a range of the entire width of the sample × 1 m to visually detect foreign matter in the film, and then the foreign matter (lint) was confirmed and evaluated with a polarizing microscope.

(Heat shrinkage)
The dimensional stability was evaluated by the heat shrinkage rate. Three test pieces each having a width of 30 mm and a length of 120 mm were collected from the vertical and horizontal directions of the sample. 6 mmφ holes were punched at both ends of the test piece at 100 mm intervals. This was conditioned for 3 hours or more in a room at 23 ± 3 ° C. and a relative temperature of 65 ± 5%. Using an automatic pin gauge (manufactured by Shinto Kagaku Co., Ltd.), the original size (L1) of the punch interval was measured to the minimum scale / 1000 mm. Next, the test piece was suspended in an incubator at 80 ° C. ± 1 ° C. and heat-treated for 3 hours, adjusted to a humidity of 23 ± 3 ° C. and a relative humidity of 65 ± 5% for 3 hours or more, and then subjected to heat treatment with an automatic pin gauge. The dimension (L2) of the punch interval was measured. And the thermal contraction rate was computed by the following formula | equation.
Thermal contraction rate = (L1-L2 / L1) × 100

(Measurement of bright spot foreign matter)
Two polarizing plates were placed in an orthogonal state (crossed Nicols) to block transmitted light, and each sample was placed between the two polarizing plates. The polarizing plate used was a glass protective plate. Light was irradiated from one side, and the number of bright spots having a diameter of 0.01 mm or more per 1 cm ² was counted with an optical microscope (50 times) from the opposite side.

(Measurement of Tg)
20 mg of a sample was placed in a DSC measurement pan. This was heated from 30 ° C. to 250 ° C. at 10 ° C./min in a nitrogen stream and then cooled to 30 ° C. at −10 ° C./min. Thereafter, the temperature was raised again from 30 ° C. to 250 ° C., and the temperature at which the baseline started to deviate from the low temperature side was defined as Tg.

(Roll dirt)
When extruding from the T-die, the degree of contamination of the roll surface at the film end of the first roll was visually observed under a reflected light source and evaluated according to the following.
A: Dirt was not seen.
B: Dirt was slightly seen.
C: Dirt was clearly recognized.
D: Dirt was noticeable on the entire surface.

(Adhesiveness)
The resulting sample film 5 cm × 5 cm was conditioned at 25 ° C. and 80% relative humidity for 3 hours, and then the casting drum surface and the air surface at the time of film formation of the film were overlapped and sealed in a moisture-proof bag. A load of 10 kg was applied to the whole. Further, the film was aged at 60 ° C. for 3 days, returned to 25 ° C. and 60% relative humidity, and after 2 hours, the adhesion marks between the films were visually confirmed and evaluated according to the following.
A: No adhesion mark was seen.
B: Slight adhesion marks were observed.
C: Adhesion marks were considerably observed.
D: It was recognized that adhesion marks were remarkably generated on the entire surface.

(Substitution degree of cellulose ester)
The substitution degree of the acyl group with respect to the hydroxyl group of cellulose is described in Carbohydr. Res. Was determined by ¹³ C-NMR according to the method described in 273 (1995) 83-91 (Tezuka et al.).

(Degree of polymerization of cellulose ester)
About 0.2 g of completely dried cellulose ester was precisely weighed and dissolved in 100 ml of a mixed solvent of methylene chloride: ethanol = 9: 1 (mass ratio). This was measured with an Ostwald viscometer for the number of seconds dropped at 25 ° C., and the degree of polymerization was determined by the following equation.
η _rel = T / T ₀
[Η] = ln (η _rel ) / C
DP = [η] / Km
[In the formula, T is the number of seconds that the sample is dropped, T ₀ 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 . ]

(Scratched)
The film for which the kimimi value was evaluated was visually observed and evaluated according to the following.
A: No damage was observed.
B: Slight damage was observed.
C: Scratch was considerably recognized.
D: The damage was recognized remarkably.

(Tensile strength, elongation rate)
A sample of 15 mm × 250 mm was conditioned at 23 ° C. and relative humidity of 65% for 2 hours, and an initial sample length of 100 mm and a tensile speed according to ISO1184-1983 with a Tensilon tensile tester (RTA-100, Orientec Co., Ltd.) The elastic modulus was calculated from the stress and elongation at the initial stage of tension at 200 ± 5 mm / min, and the tensile strength and the stretching force were evaluated.

(Alkaline hydrolyzable)
A sample 100 mm × 100 mm was saponified with an automatic alkaline saponification apparatus (manufactured by Shinto Kagaku Co., Ltd.) at 60 ° C. with a 2 mol / L sodium hydroxide aqueous solution for 3 minutes, washed with water for 4 minutes, then 30 ° C., 0 The mixture was neutralized with 0.01 mol / L dilute nitric acid for 4 minutes and washed with water for 4 minutes. Thereafter, drying was performed at 100 ° C. for 3 minutes, followed by natural drying for 1 hour, and the alkali hydrolyzability was evaluated from the following visual standard and haze values before and after the saponification treatment (25 ° C., relative humidity 60%).
A: No whitening was observed.
B: Slight whitening was observed.
C: Fair whitening was observed.
D: Remarkable whitening was observed.

(Moisture content)
A 7 mm × 35 mm sample was measured by a Karl Fischer method using a moisture measuring device and a sample drying apparatus (CA-03, VA-05, both Mitsubishi Chemical Corporation). It was calculated by dividing the amount of water (g) by the sample mass (g).

(Residual solvent amount)
Using a gas chromatography (GC-18A, manufactured by Shimadzu Corporation), the amount of the base residual solvent of the sample 7 mm × 35 mm was measured.

(Heat shrinkage)
Sample 30mm x 120mm was aged for 24 hours and 120 hours at 90 ° C and 5% relative humidity, and automatic pin gauges (manufactured by Shinto Kagaku Co., Ltd.) were used to make 6mmφ holes at both ends at 100mm intervals. (L1) was measured to a minimum scale of 1/1000 mm. Further, heat treatment was performed at 90 ° C. and 5% relative humidity for 24 hours and 120 hours, and the dimension (L2) of the punch interval was measured. The thermal contraction rate was determined by {(L1-L2) / L1} × 100.

(Elastic modulus)
Using a universal tensile tester STM T50BP manufactured by Toyo Baldwin, the stress at 0.5% elongation was measured in an atmosphere of 23 ° C. and a relative humidity of 70% at a pulling rate of 10% / min to obtain an elastic modulus.

[Comparative Example 1]
Comparative sample-1 was produced in exactly the same manner as in Example 1, except that the protective film A was not adhered in Example 1-2 (1-2), except that the cellulose ester film was in a winding roll state. .
The film obtained by winding the cellulose ester film of Comparative Sample-1 obtained on a roll-shaped core was pulled out again at a speed of 30 m / min. This process was carried out under environmental conditions with downflow type clean air and class 1000 or lower. The obtained cellulose ester film of Comparative Sample-1 was sandwiched between two orthogonal polarizing films, and when light leakage observed visually was observed, light leakage of 0.5 mm or more was observed at 11 pieces / m, It was the level which becomes a problem as a surface shape.

[Example 2]
Except that the following protective film B was used instead of the protective film A, the protective film was attached in the same manner as in Example 1, and the protective film was unwound again, and the surface state of the cellulose ester film was observed. . Here, as the protective film B, PE protection (trade name: Sekisui Protect Tape # 6221F, manufactured by Sekisui Chemical Co., Ltd.) produced by coextrusion in which the base material is PE and the pressure-sensitive adhesive layer is EVA is used. . The protective film B had a length of 1000 m (base layer 42 μm, pressure-sensitive adhesive layer 8 μm), and the total thickness was 50 μm on average. In the same manner as in Example 1, the protective film B was laminated on the cellulose ester film (Sample 1-1). The average thickness of the laminate was 130 μm. The thickness variation in the width direction and the longitudinal direction of the laminate was measured and found to be 4.6 μm and 5.2 μm, respectively. The roll length of the obtained laminate was 850 m, and a cellulose ester film laminate (laminate sample 2-1) was obtained.

  The film in which the cellulose ester film of the laminate sample 2-1 of the present invention obtained by laminating the protective film B was wound around a roll-shaped core was drawn out again at a speed of 30 m / min. In addition, this process was implemented by the environmental condition which was made into the class 1000 or less by the downflow type clean air. When the obtained cellulose ester film peeled off from the laminate sample 2-1 of the present invention was sandwiched between two orthogonal polarizing films and light leakage observed visually was observed, the light leakage of 0.2 mm was 1. Only the number of particles / m was observed, and there was no light leakage of 0.5 mm or more.

[Comparative Example 2]
In the melt film formation in (1-1) (3) of Example 1, the downstream melting temperature of 225 ° C. is 245 ° C., which is outside the temperature range of the production method of the present invention (Japanese Patent Laid-Open No. 2000-352620). A comparative cellulose ester film laminate (Comparative laminate sample 2-1) was prepared in exactly the same manner as Sample 1-2, except that the melting temperature was changed to the melting temperature listed in the example of the publication). In the same manner as in Sample 1-1, except that the downstream melting temperature 225 ° C. of the melt film formation is changed to 175 ° C. which is outside the temperature range of the production method of the present invention, a comparative cellulose ester film laminate ( Comparative laminate sample 2-2) was prepared.

The obtained comparative laminate samples 2-1 and 2-2 were evaluated according to (1-3) of Example 1. As a result, the cellulose ester films obtained from the comparative laminate samples 2-1 and 2-2 were poor in surface shape in which light leakage caused by scratches and foreign matters observed visually was observed in a streak shape in the horizontal and vertical directions. It was. These are attributed to die lines and die lines generated during the melt-casting of the cellulose ester film (both comparative samples 2-1 and 2-2 had a D-rank and a dull surface with poor surface properties). .
This is because the downstream melting temperature at the time of melt film formation of the cellulose ester film that is the substrate of the cellulose ester film laminate is outside the scope of the present invention, and this is caused by the occurrence of die streaks and dangling and the deterioration of the surface condition. Presumed.

[Example 3]
A laminate sample 3 of the present invention was produced in the same manner as in Example 1 except that the protective film A was changed to the following protective film C in Example 1.

(3-1) Preparation of pressure-sensitive adhesive used for optical protective film 2-ethylhexyl acrylate, methyl methacrylate and 2-hydroxyethyl acrylate acrylic polymer (mass ratio: 68/29/3, mass average molecular weight 400,000) To a 25% ethyl acetate solution, 3 parts by mass of trimethylolpropane tolylene diisocyanate was added to 100 parts by mass of the acrylic polymer in terms of solid content and mixed to prepare an acrylic pressure-sensitive adhesive composition.

(3-2) Preparation of protective film C On one side of a 38 μm-thick polyethylene terephthalate film, the treatment agent was applied with a wire bar so that the coating amount after drying was 0.04 g / m ^2. A treatment layer was formed by drying for a minute. Next, the acrylic adhesive composition is applied to the opposite surface of the polyethylene terephthalate film treatment layer with an applicator so that the thickness after drying is 15 μm, and dried at 120 ° C. for 2 minutes to form an adhesive layer. An optical protective film was obtained.

(3-3) Evaluation of Cellulose Ester Film Laminate The film wound around the roll core of the obtained cellulose ester film laminate (laminate sample 3) was pulled out again at a speed of 30 m / min, and a protective film Stripped off. This process was carried out under environmental conditions with downflow type clean air and class 1000 or lower. The protective film was peeled off on a winding core along the conveyance path of the laminate sample 3. The cellulose ester film obtained by peeling off the protective film was sandwiched between two orthogonal polarizing films, and light leakage caused by scratches and foreign matters observed visually was observed, and the protective film was adhered according to the present invention. No light leakage was observed in the cellulose ester film laminate (laminate sample 3), and the film was confirmed to have an excellent surface shape.

[Example 4]
The cellulose ester A used in the production of the laminate sample 1-2 of the present invention in Example 1 was changed to cellulose ester B (acetyl group substitution degree 1.10, propionyl group substitution degree 1.80, total substitution degree 2.90). , Viscosity average polymerization degree 150, water content 0.1% by mass, viscosity of 6% by mass in dichloromethane solution 52 mPa · s, average particle size 1.5 mm and powder with standard deviation 0.5 mm) Produced a laminate sample 4-1 of the present invention in exactly the same manner as the laminate sample 1-2 of Example 1. Further, cellulose ester A was converted to cellulose ester C (acetyl group substitution degree 1.00, propionyl group substitution degree 1.85, total substitution degree 2.85, viscosity average polymerization degree 160, moisture content 0.05 mass%, dichloromethane. Except for changing to a 6 mass% viscosity of 125 mPa · s in the solution, a powder having an average particle size of 1.0 mm and a standard deviation of 0.25 mm, it is exactly the same as the laminate sample 1-2 of Example 1. Thus, a laminate sample 4-2 of the present invention was produced. In the laminate samples 4-1 and 4-2, no light leakage was visually observed, and it was confirmed that the films had excellent surface shapes.

[Example 5]
Next, examples in which the cellulose ester film is applied to a polarizing plate and the like will be described.
(5-1) Preparation of Polarizing Plate (1) Saponification of Cellulose Ester Film Cellulose ester film sample 1-1 obtained by peeling from cellulose ester film laminate sample 1-2 of the present invention, and separately N, N ′ , N "-tri-m-toluyl-1,3,5-triazine-2,4,6-triamine is added in an amount of 4% by weight to the cellulose ester, and the solution is cast and dried in the presence of residual solvent The cellulose triacetate (Re is 60 nm, Rth is 200 nm, film thickness 80 μm) obtained by stretching 1.32 times in the width direction while being saponified by the following method: That is, KOH is 1.5 mol / L. After dissolution, the solution adjusted to 60 ° C. was used as a saponification solution, and 10 g / m ^{2 was} applied onto a cellulose ester film at 60 ° C. and saponified for 1 minute. Thereafter, it was washed by spraying hot water at 50 ° C. for 1 minute at a rate of 10 liters / m ² · min, and then dried at 110 ° C. at a wind speed of 15 m / second and dried for 5 minutes. The saponified film of the cellulose ester film sample 1-1 obtained by peeling from the cellulose ester film laminate sample 1-2 of the present invention was transported at a speed of 45 m / min. It was set to 1.

(2) Production of Polarizing Film According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a circumferential speed difference was given between two pairs of nip rolls and stretched in the longitudinal direction to prepare a polarizing film having a thickness of 20 μm.

(3) Bonding After sandwiching the polarizing film thus obtained between the saponified cellulose ester film sample 5-1 and the stretched cellulose triacetate film, PVA (manufactured by Kuraray Co., Ltd., PVA-117H) 3 Using a% aqueous solution as an adhesive, the polarizing axis and the longitudinal direction of the cellulose ester film sample 5-1 were laminated so as to be 90 °. Among them, the cellulose ester film 5-1 according to the present invention and a separately prepared saponified cellulose triacetate film (Re: 61 nm, Rth: 205 nm) are 20 inch VA described in FIGS. 2 to 9 of JP-A-2000-154261. After mounting it on a liquid crystal display device at 25 ° C and 60% relative humidity, bring it into an environment of 25 ° C and 10% relative humidity, and visually evaluate the change in color tone on a 10-point scale. The area where display unevenness occurred was evaluated visually, and the ratio (%) at which it occurred was determined. The color change of the cellulose ester film sample 1-1 according to the present invention was 1, which was very excellent. Moreover, according to Example 1 of Unexamined-Japanese-Patent No. 2002-86554, the cellulose ester film by this invention is similarly used also about the polarizing plate extended | stretched so that the extending | stretching axis might become an angle of 45 degrees with respect to an absorption axis using the tenter. As described above, good results were obtained.

(5-2) Preparation of optical compensation film Instead of the cellulose acetate film coated with the liquid crystal layer of Example 1 of JP-A-11-316378, a saponified cellulose ester film sample 5-1 according to the present invention was used. This was attached to the bend alignment type liquid crystal cell described in Example 9 of JP-A-2002-62431 at 25 ° C. and 60% relative humidity. This was brought into an environment of 25 ° C. and a relative humidity of 10%, the change in contrast was visually evaluated, and the color change was evaluated in 10 stages (the larger the change, the greater the change), and a mark 2 was obtained. Good performance was obtained by carrying out the present invention.

(5-3) Production of Low Reflective Film The cellulose of the present invention produced in Example 1 according to Example 47 of the Japan Society of Invention Open Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society of Invention) When the low reflection film was produced using the cellulose ester film sample 1-1 obtained by peeling off from the ester film laminate sample 1-2, good optical performance was obtained.

[Example 6]
The cellulose ester film sample 1-1 obtained by peeling from the cellulose ester film laminate sample 1-2 of the present invention produced in Example 1 was used as the cellulose triacetate film in Example 13 of JP-A No. 2002-265636. Used instead of sample 1301. A bend-alignment type liquid crystal cell was prepared by preparing an optically anisotropic layer and a polarizing plate sample in exactly the same manner as in Example 13 of JP-A-2002-265636. The obtained liquid crystal cell had excellent viewing angle characteristics.

[Example 7]
A cellulose triacetate film sample in Example 14 of Japanese Patent Application Laid-Open No. 2002-265636 was prepared by removing the cellulose ester film sample 1-1 obtained by peeling from the cellulose ester film laminate sample 1-2 of the present invention produced in Example 1. Used in place of 1401. Then, a TN type liquid crystal cell was produced by producing an optically anisotropic layer and a polarizing plate sample in exactly the same manner as in Example 14 of JP-A-2002-265636. The obtained liquid crystal cell had excellent viewing angle characteristics.

[Example 8]
(8-1) Saponification of Cellulose Ester Film Laminate with Protective Film Cellulose ester film laminate sample 1-2 of the present invention produced in Example 1 was saponified by the following method. That is, after dissolving KOH so that it might become 1.5 mol / L, what was temperature-controlled at 60 degreeC was used as a saponification liquid. Then, 10 g / m ^{2 was} applied onto a cellulose ester film at 60 ° C. and saponified for 1 minute. Thereafter, hot water at 50 ° C. was sprayed at 10 liter / m ² · min for 1 minute to perform washing. Thereafter, a drying air of 110 ° C. was sent at a wind speed of 15 m / sec and dried for 5 minutes (saponified laminate sample 1-2).

(8-2) Production of polarizing plate comprising cellulose ester film laminate with protective film According to Example 1 of JP 2001-141926 A, a peripheral speed difference is given between two pairs of nip rolls, and the film is stretched in the longitudinal direction. A polarizing film having a thickness of 20 μm (polarizing film sample 8-2) was prepared. The degree of polarization was 99.99%.

(8-3) Production of retardation film 4% by mass of N, N ′, N ″ -tri-m-toluyl-1,3,5-triazine-2,4,6-triamine was added to the cellulose ester. Cellulose triacetate (Re: 60 nm, Rth: 200 nm, film thickness: 80 μm) obtained by casting a solution and drying in the width direction while drying in the presence of residual solvent was saponified according to the following: Then, KOH was dissolved to 1.5 mol / L and then adjusted to 60 ° C. and used as a saponification solution, and 10 g / m ^{2 was} applied onto a cellulose triacetate film at 60 ° C. and saponified for 1 minute. was. after this, the spray of 50 ° C. warm water, then washed sprayed for one minute at 10 l / m ² · min. Thereafter, sends 110 ° C. in dry air at wind speed 15 m / sec, for 5 minutes Was 燥. The sample was a cellulose triacetate film sample 8-3.

(8-4) Production of Retardation Plate A saponified laminate sample 1-2 with a protective film according to the present invention and a cellulose triacetate sample 8-3 for retardation are laminated using a polarizing film sample 8-2. Sample 1-2 / PVA (manufactured by Kuraray Co., Ltd., PVA-117H) 3% aqueous solution / polarizing film sample 8-2, PVA (manufactured by Kuraray Co., Ltd., PVA-117H) 3% aqueous solution / cellulose triacetate film sample 8- A phase difference plate was produced by sandwiching the film with three layer structures. At this time, the polarizing axis and the slow axis direction of the cellulose ester film sample 1-1 were bonded to each other at 90 ° to obtain a retardation plate sample 8-4 having the cellulose ester film laminate of the present invention.

(8-5) Evaluation The protective film of the obtained retardation plate sample 8-4 was peeled off, the two pieces were superposed so that the polarization axes were orthogonal, and the foreign matter was visually observed to find 0.2 mm. The above bright spot foreign matter was not observed at all. From this, it was demonstrated that the cellulose ester film laminated body which laminated | stacked the protective film by this invention was excellent also in the handling at the time of preparation of the phase difference plate.

[Comparative Example 3]
In Example (8-1), the cellulose ester film laminate sample 1-2 of the present invention prepared in Example 1-2 (1-2) was prepared in Example 1-1 (1-1). A comparative retardation plate sample 8-5 was obtained in the same manner as in Example 8, except that the cellulose ester film sample 1-1 was changed according to the invention. Two obtained retardation plate samples 8-5 were prepared, overlapped so that their polarization axes were orthogonal to each other, and the foreign matters were visually observed. As a result, there were 3 bright spot foreign matters of 1 mm or more / m ^2. In addition, 12 bright spot foreign matters having a size of 0.5 mm or more were observed / m ² . Therefore, compared with the case where the protective film according to the present invention of Example 8 is applied, the comparative retardation plate sample 8-5 without the protective film has a problem due to the generation of foreign matters during the handling of the retardation plate. Was included. From the above, it was proved that the cellulose ester film laminate of the present invention was excellent.

[Example 9]
(9-1) Preparation of saponification-treated film Alkaline saponification aqueous solution having the following formulation kept at 40 ° C. on one side (air side) of cellulose ester film sample 1-1 obtained in (1-1) of Example 1. (S-1) was applied at 20 ml / m ² with a rod coater. After being kept under a steam far-infrared heater heated to 110 ° C. (manufactured by Noritake Co., Ltd.) for 7 seconds to bring the surface temperature of the film to 40 to 50 ° C., pure water was also used using a rod coater. 20 ml / m ^{2 was} applied to wash off the alkaline solution. At this time, the film temperature was maintained at 40 to 45 ° C., and the KOH concentration of the coating film after application of pure water was 0.5 mol / L. Next, washing with a fountain coater and draining with an air knife were repeated three times, and after washing off the alkali, it was retained in a drying zone at 70 ° C. for 15 seconds and dried to produce a saponified film (Sample 1-1-K1).

Alkali saponification aqueous solution (S-1) formulation KOH 560 parts by mass C ₁₄ H ₂₉ —O— (CH ₂ CH ₂ O) —H 100 parts by mass Antifoaming agent Surfynol DF110D (manufactured by Nissin Chemical Industry Co., Ltd.) 2 parts by mass Part Water 9338 parts by weight The surface tension of the alkali saponification aqueous solution S-1 is 64 mN / m, the viscosity of the liquid is 1.8 mPa · s, the density of the liquid is 1.07 g / cm ³ , and the electric conductivity is 180 mS / cm. Met. The carbonate ion concentration in the alkaline saponification aqueous solution was 1090 mg / L, the total concentration of polyvalent metal ions including calcium and magnesium was 190 mg / L, and the chloride ion concentration was 133 mg / L.

(9-2) Adhesion and Evaluation of Protective Film A protective film A was laminated on the saponified surface of the obtained saponified film sample 1-1-K1 in the same manner as in (1-2) of Example 1 to obtain a cellulose ester. A film laminate sample K1-A was prepared. The average thickness of the obtained laminate sample K1-A was 105 μm. Moreover, when the thickness dispersion | variation in the width direction and longitudinal direction of a laminated body was measured, they were 2.5 micrometers and 1.0 micrometers, respectively.
The same evaluation as (1-3) of Example 1 was performed on the laminate sample K1-A. As a result, it was confirmed that the laminate sample K1-A was a film having an excellent surface shape with no light leakage observed visually. Moreover, about the cellulose-ester film provided from the laminated body sample K1-A, all obtained the same measurement result and evaluation result as (1-3) of Example 1. FIG.

[Comparative Example 4]
Comparative sample-4 was produced in exactly the same manner as in Example 9, except that protective film A did not adhere in Example 9.
The film in which the cellulose ester film of Comparative Sample-4 obtained was wound around a roll-shaped core was pulled out again at a speed of 30 m / min. This process was carried out under environmental conditions with downflow type clean air and class 1000 or lower. The obtained cellulose ester film of Comparative Sample-4 was sandwiched between two orthogonal polarizing films, and when light leakage observed visually was observed, light leakage of 0.5 mm or more was observed at 11 pieces / m, It was the level which becomes a problem as a surface shape.

[Example 10]
The same treatment as in Examples 2 to 8 was performed, except that the saponified film sample 1-1-K1 obtained in Example 9 and the cellulose ester film laminate sample K1-A were used. As a result, the same results as in Examples 2 to 8 were obtained, and the excellent effects of the present invention were confirmed in the same manner.

[Example 11]
In “(3) Melt film formation” of “(1-1) Film formation of a cellulose ester film as a substrate of a cellulose ester film laminate” in Example 1, it is described in Example 1 of JP-A-11-235747. Touch rolls (those with a description of a double hold-down roll) (thin metal outer cylinder thickness was 3 mm), and touch roll film formation was performed (except for the touch roll film formation, all examples) 1). Fine irregularities and the blur width in the liquid crystal display device were improved by touch roll film formation.

  In addition, the same touch roll as described in the first embodiment of the pamphlet of International Publication No. 97/28950 is used (the sheet roll is described as a roll) (however, the cooling water used for the metal outer cylinder is from 18 ° C. to 120 ° C.). The oil was changed to oil at 0 ° C.), and the touch roll linear pressure was 15 kg / cm and the touch roll temperature was 115 ° C. When the number of fine irregularities was measured by the above method, the number of cellulose ester films of Example 1 was 3, whereas when the touch roll was used, the number was 0, and the touch roll film forming method was further improved. It was confirmed to be excellent.

(Fine irregularities)
The cellulose acylate film was measured under the following conditions using a three-dimensional surface structure analysis microscope (New View 5022 manufactured by Zygo).
Objective lens: 2.5 times Image zoom: 1 time Measurement field of view: 2.8 mm in the width direction (TD), 2.1 mm in the longitudinal direction (MD)
Among them, the number of peaks (convex portions) having a height of 0.1 μm to 100 μm and valleys (concave portions) having a depth of 0.1 μm to 100 μm were counted. However, a convex part and a recessed part point out what is connected 1 mm or more continuously in MD direction. The number of the convex portions and concave portions was divided by the measurement width (2.8 mm) and then multiplied by 100 to obtain the number of convex portions and concave portions per 10 cm. The above measurement was performed by measuring 30 points at equal intervals over the entire width of the formed sample film and averaging it, thereby obtaining the number of convex portions and concave portions per 10 cm width.

[Example 12]
(1) Synthesis of cellulose acylate D After spraying 0.1 parts by mass of acetic acid and 2.7 parts by mass of propionic acid to 10 parts by mass of cellulose (hardwood pulp), the mixture was stored at room temperature for 1 hour. Separately, a mixture of 1.2 parts by mass of acetic anhydride, 61 parts by mass of propionic anhydride, and 0.7 parts by mass of sulfuric acid was prepared, cooled to -10 ° C, and then mixed in the reaction vessel with the pretreated cellulose. did.
After 30 minutes, the external temperature was raised to 30 ° C. and reacted for 4 hours. 46 parts by mass of 25% aqueous acetic acid was added to the reaction vessel, the internal temperature was raised to 60 ° C., and the mixture was stirred for 2 hours. 6.2 parts by mass of a solution prepared by mixing equal parts of magnesium acetate tetrahydrate, acetic acid and water was added and stirred for 30 minutes. The reaction solution was filtered under pressure with a sintered metal filter having a reserved particle diameter of 40 μm, 10 μm, and 5 μm in order to remove foreign matters. The reaction solution after filtration was mixed with 75% aqueous acetic acid to precipitate cellulose acetate propionate, and then washed with warm water at 70 ° C. until the pH of the washing solution reached 6-7. Furthermore, after performing the process stirred for 0.5 hour in 0.001% calcium hydroxide aqueous solution, it filtered. The obtained cellulose acetate propionate was dried at 70 ° C. Cellulose acetate propionate obtained from ¹ H-NMR measurement had a substitution degree of acetyl group of 0.15, a substitution degree of propionyl group of 2.55, a weight average molecular weight of 135,000 and a number average molecular weight of 52,000.

(2) Pelletization After this cellulose ester D was dried at 105 ° C. for 5 hours to make the water content 0.07% by mass, silica fine particles having a primary average particle size of 20 nm were added to the cellulose ester solid content by 0.007. % By weight, UV agent a {2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine} as an ultraviolet absorber 0.4% by mass, UV agent b {2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole} 0.4% by mass, and UV agent c {2 0.4% by mass of (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole}, 2% by mass of plasticizer a {biphenyldiphenyl phosphate}, plasticizer 2% by mass of b {trimethylolpropane tribenzoate}, 2% by mass of plasticizer c {ethylfurylethyl glycolate}, bis (2,6-di-tert-butyl-4-methylphenyl) penta as a stabilizer 0.1% by weight of erythritol di-phosphite, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6-[(2H-benzotriazol-2-yl) phenol ]] By mass, and bis [(1,2,2,6,6-pentamethyl-4-piperidinyl) 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2- 0.1% by mass of n-butyl malonate, tridecafluoroethyl methacrylate / poly (average polymerization degree 5) oxyethylene methacrylate / butyl acrylate = 30 as a release agent / 20/50 (molar ratio, molecular weight 9000) is added by 0.1% by mass, and 0.00005% by mass of 1,4-bis (2,4,6-tripropylcyclohexylsulfonamidophenyl) anthraquinone is added as a dye. did.

  These were mixed and dried to a moisture content of 0.1% or less, then charged into a hopper of a twin-screw kneading extruder, melted by kneading at 150 to 200 ° C. with a screw speed of 300 rpm and a residence time of 40 seconds. . This was extruded from a die at a rate of 200 kg / hour into a strand having a diameter of 3 mm, immersed in a 50 ° C. water bath for 1 minute (strand solidification), passed through 10 ° C. water for 30 seconds, and the temperature was lowered to a length of 5 mm. To obtain pellets. The obtained pellets of cellulose ester D were dried at 105 ° C. for 120 minutes, and then stored in a moisture-proof bag made of a laminate film having aluminum.

(3) Film formation This was put into a hopper adjusted to be (Tm-10 ° C), and a full flight screw with a compression temperature of 3.5 at a melting temperature of 230 ° C was used. The mixture was kneaded and melted at a screw diameter of 30. Furthermore, after performing breaker plate type filtration at the outlet of the extruder, after passing through a 4 μm stainless steel leaf type disk filter type filtration device after passing through the gear pump, it is extruded from a T-die. Example of JP-A-11-235747 The film was formed at a touch pressure of 0.3 MPa using the touch roll described in 1. This was peeled off from the casting roll and wound up. In addition, after trimming both ends (each 3% of the total width) just before winding, after applying thickness processing (knurling) with a width of 10 mm and a height of 50 μm at both ends, 3000 m with a width of 1.5 m is wound into a roll. I took it. The organic solvent content (by gas chromatography method) of this film was 0.01% by mass or less.

(4) Adhesion of protective film As protective film A, a PET protective tape (product number: S-362, manufactured by Fujimori Kogyo Co., Ltd.) whose base material is a PET film (25 μm thickness) and whose adhesive layer is an acrylic adhesive (20 μm thickness). It was used. On one side (casting roll surface side) of the cellulose ester film prepared above, the protective film A is a nip roll formed by a combination of a rubber roll and a metal roll, and the casting roll surface side of the cellulose ester film and the protective film A is Y-shaped. Then, the laminate film was obtained by being sandwiched between the nip rolls in a state where both of them were partially along each other and bonded together to obtain a laminate film. When the thickness variation in the width direction and the longitudinal direction of the laminate was measured, they were 3.0 μm and 0.8 μm, respectively. In addition, this process was implemented under the environmental conditions of class 1000 or less under downflow type clean air.

When this cellulose acylate film was evaluated in accordance with the method described in (1-3) of Example 1, it was confirmed that the film was a die line A and danmura A and had good surface properties.
The tilt width is 20.1 nm, the limit wavelength is 386.1 nm, the absorption edge is 377.1 nm, the absorption at 380 nm is 1.5%, the axis deviation (molecular orientation axis) is 0.18 °, and the elastic modulus is The longitudinal direction is 3.00 GPa, the width direction is 2.91 GPa, the tensile strength is 120 MPa in the longitudinal direction, the width direction is 110 MPa, the elongation is 55% in the longitudinal direction, and the width direction is 60%. Yes, the curl value was -0.11 at a relative humidity of 25% and 1.3 at a wet (relative humidity of 10% or less). The moisture content was 2.1% by mass, and the thermal shrinkage was −0.09% in the longitudinal direction and −0.05% in the width direction. The foreign matter had a lint of less than 5 pieces / m. Bright spots of 0.02 mm or less were less than 2/3 m, 0.02-0.05 mm were less than 1/3 m, and 0.05 mm or more were not found.
These had excellent properties for optical applications. Moreover, the adhesiveness after application was A, and the moisture permeability was also good (610 g / m ² · day). Residual solvent was not detected.

  Further, when the number of fine irregularities of this cellulose acylate film was measured according to the method described in Example 11, a film having zero fine irregularities was obtained.

  From this cellulose acylate film, according to the method described in Examples 5 to 8, from a polarizing plate, an optical compensation film, a low reflection film, a bend alignment type liquid crystal cell, a TN type liquid crystal cell, and a cellulose ester film laminate with a protective film. When a polarizing plate, a retardation film, and a retardation plate were produced, all exhibited excellent performance.

[Example 13]
In the same manner as in Example 12, except that cellulose acylate E having a propionyl group substitution degree of 1.5, an acetyl group substitution degree of 1.0, a weight average molecular weight of 150,000, and a number average molecular weight of 56,000 was used instead of cellulose acylate D. When a film was prepared and evaluated, all obtained good results.

[Example 14]
A film was prepared and evaluated in the same manner as in Example 12 except that cellulose acylate F having a substitution degree of propionyl group of 0.8, an substitution degree of acetyl group of 1.8 and a weight average molecular weight of 160000 was used instead of cellulose acylate D. As a result, good results were obtained.

[Example 15]
Similar to Example 12 except that cellulose acylate F having a substitution degree of propionyl group of 0.8, an substitution degree of acetyl group of 1.8 and a weight average molecular weight of 160000 was used in place of cellulose acylate D, and no plasticizer was added. When a film was prepared and evaluated, all obtained good results.

[Example 16]
Instead of cellulose acylate D, cellulose acylate F having a substitution degree of propionyl group of 0.8, an substitution degree of acetyl group of 1.8, and a weight average molecular weight of 160000 was used, and instead of the plasticizer of Example 12, trimethylolpropane tri A film was prepared and evaluated in the same manner as in Example 12 except that 10% by mass of benzoate was used with respect to cellulose acylate E, and good results were obtained in all cases.

  The cellulose ester film laminate of the present invention can easily supply a cellulose ester film having a good surface shape and no scratches by peeling off the protective film. Moreover, according to the manufacturing method of this invention, the damage to the film surface in a process process, etc. can be suppressed significantly, and the cellulose-ester film laminated body which has said characteristic can be provided simply. If the cellulose ester film laminate of the present invention is used, a polarizing plate, an optical compensation film and an antireflection film excellent in optical properties, and a liquid crystal in which a foreign matter failure on a display screen and a change in visibility over time are suppressed. A display device can be easily manufactured. Therefore, the present invention has high industrial applicability.

It is the schematic which shows the one aspect | mode of the apparatus for performing the melt film forming by a touch roll method.

Explanation of symbols

1 Melt 2 Casting drum 3 Extruder 4 Die lip 5 Touch roll

Claims (16)

Cellulose ester film lamination in which a protective film is laminated in contact with at least one surface of a cellulose ester film satisfying the following formulas (S-1) to (S-3) and having a residual solvent amount of 0.01% by mass or less. Body,
The protective film comprises a resin substrate and an adhesive layer, and the resin substrate is selected from the group consisting of polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, polyimide, polystyrene, polyacrylonitrile, and polymethacrylate. Containing at least one, and the pressure-sensitive adhesive layer contains at least one selected from the group consisting of an acrylic polymer and an ethylene-vinyl acetate copolymer,
A cellulose ester film laminate in which streaky light leakage is not observed even when the cellulose ester film obtained by peeling the protective film from the cellulose ester film laminate is sandwiched between two orthogonal polarizing plates and visually observed.
Formula (S-1) 2.5 <= A + B <= 3.0
Formula (S-2) 0 ≦ A ≦ 2.2
Formula (S-3) 0.8 ≦ B ≦ 3.0
(In the formula, A represents the substitution degree of the acetyl group to the hydroxyl group of cellulose, and B represents the substitution degree of the acyl group having 3 to 22 carbon atoms to the hydroxyl group of cellulose.)   The cellulose ester film laminate according to claim 1, wherein the acyl group having 3 to 22 carbon atoms substituted for the hydroxyl group of cellulose in the cellulose ester is at least one of propionyl group and butyryl group. body.   The cellulose ester film laminate according to claim 1 or 2, wherein the cellulose ester film contains at least one selected from the group consisting of fine particles, an ultraviolet absorber, a plasticizer, and a stabilizer.   The cellulose ester film laminate according to any one of claims 1 to 3, wherein the cellulose ester film is melt-formed using a touch roll. The cellulose plane retardation ester film (Re) is from 0 to 300 nm, and, one of the thickness-direction retardation (Rth) of claim 1-4, characterized in that the -300~700nm one The cellulose ester film laminate according to Item. A step of forming a cellulose ester film by melting a cellulose ester satisfying the following formulas (S-1) to (S-3) at 180 to 230 ° C. and extruding it from a die, and protecting at least one side of the cellulose ester film film is brought into contact with have a step of laminating,
The protective film comprises a resin substrate and an adhesive layer, and the resin substrate is selected from the group consisting of polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, polyimide, polystyrene, polyacrylonitrile, and polymethacrylate. A method for producing a cellulose ester film laminate, comprising at least one selected from the group consisting of an acrylic polymer and an ethylene-vinyl acetate copolymer .
Formula (S-1) 2.5 <= A + B <= 3.0
Formula (S-2) 0 ≦ A ≦ 2.2
Formula (S-3) 0.8 ≦ B ≦ 3.0
(In the formula, A represents the substitution degree of the acetyl group to the hydroxyl group of cellulose, and B represents the substitution degree of the acyl group having 3 to 22 carbon atoms to the hydroxyl group of cellulose.) It melt-forms using a touch roll, The manufacturing method of the cellulose-ester film laminated body of Claim 6 characterized by the above-mentioned. The method for producing a cellulose ester film laminate according to claim 6 or 7 , further comprising a step of saponifying at least one surface of the cellulose ester film. The method for producing a cellulose ester film laminate according to claim 8 , wherein a step of laminating the protective film is performed after the saponification step. The method for producing a cellulose ester film laminate according to claim 9 , wherein the protective film is laminated on the saponified surface. The method for producing a cellulose ester film laminate according to claim 8 , wherein a step of laminating the protective film is performed before the saponification step. Cellulose ester film laminate produced by the method according to any one of claims 6-11. A polarizing plate using a cellulose ester film obtained from the cellulose ester film laminate according to any one of claims 1 to 5 or 12 as a polarizing film. An optical compensation film using a cellulose ester film obtained from the cellulose ester film laminate according to any one of claims 1 to 5 or 12 . An antireflection film comprising a cellulose ester film obtained from the cellulose ester film laminate according to any one of claims 1 to 5 or 12 . A liquid crystal display comprising at least one selected from the group consisting of the polarizing plate according to claim 13 , the optical compensation film according to claim 14 , and the antireflection film according to claim 15. apparatus.

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