JP2008080651A - Cellulose ester film laminate and manufacturing method of the same, polarizing plate, optical compensation film, reflection preventing film, and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellulose ester film laminate capable of supplying the cellulose ester film having good face condition and no flaw with a small amount of charging. <P>SOLUTION: The cellulose film laminate includes a releasable protection film made of a resin substrate and an adhesive layer having electrical conductivity of 10<SP>12</SP>Ω or less overlying one face of a cellulose ester film satisfying equations: 2.0≤A+B≤3.0, 0≤A≤2.5 and 0.5≤B≤3.0 and whose remaining solvent quantity is 0.01 mass% or less. In the equation, A and B respectively represent substituting rate acetyl groups to hydroxyl groups of the cellulose, and acyl groups with 3 to 22C. <P>COPYRIGHT: (C)2008,JPO&INPIT

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 producing a cellulose triacetate film used in a liquid crystal display device, a solution casting method in which cellulose triacetate is dissolved in a chlorinated organic solvent and cast on a substrate and dried to form a film is mainly used. Has been 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, adopting a stricter closed system to prevent the organic solvent from leaking out from the system, or adsorbing the organic solvent through the gas absorption tower before releasing it into the outside air even if the organic solvent leaks from the film forming process. 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 used in the conventional solution casting method 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. However, these cellulose ester films have a drawback that they are easily damaged as compared with conventional cellulose triacetate films. Therefore, when the cellulose ester film is wound on a long roll, the conventional technique for imparting handling properties using colloidal silica fine particles is difficult to apply because it is easily damaged. In particular, the melt-formed cellulose ester film is easily scratched and the handling property imparting effect by the colloidal silica fine particles is insufficient.

  On the other hand, when manufacturing a product using an optical film such as a polarizing plate, a phase difference plate, or a lens film, a peelable protective film is adhered to the surface of the optical film, and the surface becomes dirty in the subsequent process. It is known to prevent damage. It is also known to perform an appearance inspection of an optical film with a peelable protective film adhered. A conventional typical peelable protective film has a configuration in which a slightly adhesive pressure-sensitive adhesive layer is provided on one surface of a base film. Here, the pressure-sensitive adhesive layer is used as a layer for attaching the peelable protective film to the optical film. The purpose of making the pressure-sensitive adhesive layer slightly sticky is to provide functionality that can be smoothly peeled off and has no adhesive residue when the used peelable protective film is peeled off from the surface of the optical film. Because it is.

  However, if the peelable protective film has a large amount of charge, the static electricity generated during the manufacturing process causes foreign matter to be adsorbed on the optical film, or when the peelable protective film is peeled off and removed, the circuit is damaged. There is a risk of destruction. For this reason, an attempt has been made to prevent charging by adding an antistatic layer to the peelable protective film to reduce the surface resistance value. As the antistatic layer, a layer containing various surfactants (cationic, anionic or amphoteric surfactants), a functional group-containing polymer, or the like, or a vapor deposition layer of metal or metal oxide is used.

For example, Patent Document 3 discloses a peelable protective film in which an antistatic layer containing a transparent conductive polymer is provided between a transparent substrate film and an adhesive layer. As the transparent conductive polymer, an acrylate monomer having a quaternary ammonium salt group is described. Patent Document 4 discloses a peelable protective film in which an antistatic layer containing a quaternary ammonium salt is provided between a transparent substrate film and an adhesive layer. Each of the substrate films described in these publications is characterized in that a conductive layer containing a quaternary ammonium salt is provided between the substrate film and the pressure-sensitive adhesive layer.
Japanese National Patent Publication No. 6-501040 JP 2000-352620 A JP 2000-85068 A JP 2000-273417 A

  As described above, in the manufacturing process of the liquid crystal panel, when the peelable protective film stuck on the optical film is peeled and removed, there are cases where circuit components such as a driver IC for liquid crystal are destroyed due to peeling charging. ing. In addition, in order to reduce power consumption, the driving voltage of the liquid crystal material used for the liquid crystal panel is decreasing, and accordingly, the breakdown voltage of the driver IC is also decreasing. For this reason, recently, it has been demanded to suppress the peeling band voltage preferably in the range of −0.7 kV to +0.7 kV.

  However, in the conventional peelable protective film, since the antistatic layer is provided between the base film and the adhesive, the optical film as the adherend or the liquid crystal cell to which the optical film is attached In addition, it is impossible to prevent static electricity damage to the driver IC connected thereto. In addition, in order to provide the antistatic layer, one coating / drying step is required, which is disadvantageous in terms of cost.

  In particular, in the cellulose ester film, generation of an electrostatic charge is strongly observed, and when foreign substances such as dust adhere to the surface of the cellulose ester film, it is difficult to remove the cellulose ester film. This is considered to be due to the fact that the cellulose ester film contains various additives and is easily hydrated. Furthermore, the cellulose ester film is sensitive to scratches, and in the state in which foreign substances adhering to the electrostatic charge are taken into the roll in the form of a cellulose ester film roll, scratches are generated between the cellulose ester film films. It becomes a big problem as an industrial film.

  In view of these problems of the prior art, an object of the present invention is to provide a cellulose ester film laminate with a protective film 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. Furthermore, an object of the present invention is to provide a polarizing plate, an optical compensation film and an antireflection film which have good handling properties during processing and excellent optical characteristics. Furthermore, an object of the present invention is to provide a releasable protective film that allows an appearance inspection of an optical component to be performed while a releasable protective film is stuck on an optical component such as a polarizing plate. It is another object of the present invention 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. It is another object of the present invention to provide a cellulose ester film that is free from electrostatic failure and failure due to dust when the cellulose ester film is peeled off from the releasable protective layer film.

These objects have been achieved by the present invention having the following configuration.
[1] Conductivity of 10 ¹² Ω or less on at least one surface of a cellulose ester film satisfying the following formulas (S-1) to (S-3) in an environment of at least one resin substrate and 25 ° C. and a relative humidity of 40%. Cellulose ester film laminate in which a releasable protective film comprising at least one pressure-sensitive adhesive layer having properties is laminated.
Formula (S-1) 2.0 <= A + B <= 3.0
Formula (S-2) 0 ≦ A ≦ 2.5
Formula (S-3) 0.5 ≦ 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 ester film laminate according to [1], wherein the cellulose ester film satisfying the formulas (S-1) to (S-3) is melt-formed.
[3] The cellulose ester film laminate according to [1], wherein a residual solvent amount of the cellulose ester film satisfying the formulas (S-1) to (S-3) is 0.01% by mass or less. .

[4] The cellulose according to any one of [1] to [3], wherein the conductivity of the pressure-sensitive adhesive layer is 10 ¹² Ω or less in an environment of 25 ° C. and a relative humidity of 10%. Ester film laminate.
[4 ′] The conductivity of the pressure-sensitive adhesive layer is 10 ¹² Ω or less in an environment of 25 ° C. and a relative humidity of 60%, according to any one of [1] to [3] Cellulose ester film laminate.
[4 "] The conductivity of the pressure-sensitive adhesive layer is 10 ¹² Ω or less in an environment of -5 ° C or higher and a relative humidity of 10% or higher. Any one of [1] to [3] Cellulose ester film laminate as described in 1.
[5] When the releasable protective film is peeled from the cellulose ester film, the stripping voltage is −1 kV to +1 kV in an environment of 25 ° C. and a relative humidity of 60%. [1] to [4] ] The cellulose-ester film laminated body as described in any one of.
[6] The pressure-sensitive adhesive layer of the releasable protective film comprises a pressure-sensitive adhesive containing a quaternary substituted ammonium salt or pyridium salt, an acrylic polymer having a hydroxyl group, and a polyisocyanate [1] -The cellulose-ester film laminated body as described in any one of [5].

[7] The cellulose ester according to any one of [1] to [6], wherein the surface roughness of the surface opposite to the pressure-sensitive adhesive layer of the releasable protective film is 0.002 μm or more. Film laminate.
[8] The resin base material of the releasable protective film contains at least one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polycarbonate, polyimide, polystyrene, polyacrylonitrile, and polymethacrylate. The cellulose ester film laminate according to any one of [1] to [7].

[9] 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 [1] to [8] The cellulose-ester film laminated body as described in any one of these.
[10] The cellulose ester has a weight average molecular weight (Mw) of 50,000 to 350,000 and a weight average molecular weight / number average molecular weight (Mw / Mn) of 1.5 to 5.0. The cellulose ester film laminate according to any one of 1] to [9].

[11] In any one of [1] to [10], 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 laminated body of description.
[12] 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 [11] ] The cellulose-ester film laminated body as described in any one of.

[13] A method for producing a cellulose ester film laminate according to any one of [1] to [12],
A step of producing a cellulose ester film by melt film formation;
The cellulose ester film is the adhesive material layer side of a releasable protective film comprising at least one resin substrate and at least one adhesive layer having a conductivity of 10 ¹² Ω or less in an environment of 25 ° C. and relative humidity of 40%. And a step of laminating the cellulose ester film laminate.

[14] The method for producing a cellulose ester film laminate according to [13], wherein the melt formation of the cellulose ester film is performed at a melting temperature of 180 to 240 ° C.
[15] The method for producing a cellulose ester film laminate according to [13] or [14], wherein the melt film formation is performed using a touch roll.
[16] The method for producing a cellulose ester film laminate according to any one of [13] to [15], further comprising a step of saponifying at least one surface of the cellulose ester film.

[17] Adhesion appearing by preparing a release protective film with a release sheet in which a release sheet is laminated on the adhesive layer of the release protective film, and peeling the release sheet from the release protective film with a release sheet. The method for producing a cellulose ester film laminate according to any one of [13] to [16], wherein the cellulose ester film is laminated on a material layer.
[18] The process according to any one of [13] to [17], wherein the step of laminating the releasable protective film and the cellulose ester film is performed in air cleaned to a class 10000 or lower. The manufacturing method of description cellulose-ester film laminated body.

[19] Use of a polarizing film and a cellulose ester film obtained by peeling off the releasable protective film from the cellulose ester film laminate according to any one of [1] to [12]. A characteristic polarizing plate.

[20] An optical compensation using a cellulose ester film obtained by peeling off the releasable protective film from the cellulose ester film laminate according to any one of [1] to [12]. the film.

[21] Antireflection using a cellulose ester film obtained by peeling off the releasable protective film from the cellulose ester film laminate according to any one of [1] to [12]. the film.

[22] At least one selected from the group consisting of the polarizing plate according to [19], the optical compensation film according to [20], and the antireflection film according to [21] is used. Liquid crystal display device.

  The cellulose ester film laminate of the present invention can easily supply a cellulose ester film having a small surface charge, good surface shape and no scratches by peeling off the protective film. In addition, according to the production method of the present invention, the cellulose ester film laminate having the above-mentioned characteristics can be greatly improved by greatly suppressing scratches on the film surface in the processing step of the optical material, and greatly improving the dusting caused by static electricity. Can be provided easily. Furthermore, the polarizing plate, the optical compensation film and the antireflection film of the present invention have excellent optical characteristics, and the liquid crystal display device of the present invention has a foreign matter failure (such as a bright spot foreign matter) on the display screen and a change in visibility over time. Is suppressed.

  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) 2.0 <= A + B <= 3.0
Formula (S-2) 0 ≦ A ≦ 2.5
Formula (S-3) 0.5 ≦ B ≦ 3.0
In the formula, A represents the degree of substitution of the acetyl group with respect to the hydroxyl group of cellulose, and B represents the degree of substitution of the acyl group having 3 to 22 carbon atoms with respect 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 2.20 ≦ A + B ≦ 3.0, and further preferably 2.5 ≦ A + B ≦ 3.0. A is preferably 0 ≦ A ≦ 2.3, and B is preferably 0.5 ≦ B ≦ 3.0, more preferably 0.7 ≦ 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 preferable 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 constituting the ester of cellulose ester used in the present invention may be a single type or a plurality of types as long as the conditions (S-1) to (S-3) are satisfied. .

  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 weight average molecular weight (Mw) of the cellulose ester preferably used in the present invention is 50,000 to 350,000, more preferably 70,000 to 250,000, and particularly preferably 90,000 to 200,000. The cellulose ester used in the present invention preferably has a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of 1.5 to 6.0, more preferably 1.5 to 5.5. More preferably, it is 2.0-5.5, More preferably, it is 2.5-5.0. Moreover, an average degree of polymerization is 100-700 normally, More preferably, it is 120-550, More preferably, it is 120-400, Especially preferably, it is 130-350.

  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. It is desirable to select and mix molecular components.

The cellulose ester is preferably pelletized before melt film formation. The size of a preferable pellet is 1 mm ^{3 to} 20 cm ³ , more preferably 3 mm ^{3 to} 10 cm ³ , and still more preferably 5 mm ³ to 5 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), Adecastap LA-51 ( Asahi Denka), Chemisorp 111 (Chemipro Kasei), UVINUL D-49 (BASF), etc. Examples of oxalic acid anilide UV absorbers include TINUBIN 312 (Ciba Specialty Chemicals) and TINUBIN 315 (Ciba Specialty Chemicals). 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. ) And the like. Examples of the polymer ultraviolet absorber include 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. In the case of producing a cellulose ester film by 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 a 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 stabilizers, compounds described in [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 Society for Invention and Technology (Public Technical Number 2001-1745, issued on March 15, 2001, Japan Society 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 here 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. A polymer having a fluorine atom can exhibit an action as a release agent. As a polymer which has a fluorine atom, the polymer as described in 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, 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 cellulose ester film and prevent oxidation of the film. Such a dye such as a blue dye is also an additive having the same effect as the plasticizer. Preferable dyes include anthraquinone dyes. The anthraquinone dye may have an arbitrary substituent at positions 1 to 8 of the anthraquinone. Preferred substituents include an optionally substituted anilino group, hydroxyl group, amino group, and nitro group. The addition amount is preferably in the range of 0.000005 to 1 part by mass, more preferably in the range of 0.00005 to 1.5 parts by mass, with respect to 100 parts by mass of the cellulose ester. More preferably, it is in the range of -0.5 parts by mass.

[Film forming process]
In general, a cellulose ester film is formed by casting a melt film forming method in which a cellulose ester is melted and cast without using a solvent, or by casting a solution in which a cellulose ester is dissolved in a solvent. It can be produced by a solution casting method. 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. A desired cellulose ester film is obtained. The optimization of melt film forming conditions is described in detail below.

In addition, it is preferable to implement a melt film-forming process in the air cleaned to class 1000 or less. Moreover, it is preferable to carry out the steps before and after the melt film formation in air cleaned to class 1000 or less as much as possible. Specifically, the process from the filtration step after cellulose ester synthesis to pelletization, the step of laminating the cellulose ester film after melt film formation with the peelable protective film, etc. in the air cleaned to class 1000 or less It is preferable to implement in. In the present invention, class 500 or less is more preferable, and class 200 or less is more preferable.
The cleanliness classification here is performed according to the number of fine particles (dust / dust) having a particle size of 0.5 μm or more contained in 1 cubic foot (about 28 liters) of air. That is, if there are 200 or less dust or dust having a particle size of 0.5 μm or more in 1 cubic foot of air, it is class 200, if it is 500 or less, class 500, if it is 1,000 or less, class 1,000. Become.

(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 the cellulose ester pelletized by the above-mentioned method, and the moisture content in the pellet is preferably 1% or less, more preferably 0.5% or less prior to melt film formation. More preferably, after making it 0.01% or less, it is put into a hopper of a melt extruder. At this time, the temperature of the hopper is preferably 20 ° C to 110 ° C, more preferably 40 ° C to 100 ° C, and still more 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, but this is not limited as long as the desired moisture content can be obtained. 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 part that quantitatively transports the cellulose ester supplied from the supply port, a compression part that melt-kneads and compresses the cellulose ester, and a weighing part that measures the melt-kneaded and compressed cellulose ester in order from the supply port side. 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 preferably 180 ° C to 240 ° C, more preferably 190 ° C to 230 ° C, and further 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, mudock, and dalmage, but cellulose esters with relatively poor thermal stability. It is preferable to use a full flight type resin. Biaxial extruders can be broadly classified into two types, the same direction and different directions, and both types can be used, but the same direction rotation type is preferred.

(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. As the die, a T die is preferably used, and a fishtail die and a hanger coat die are also included in the category of T-die. In casting, it is preferable to increase the adhesion between the casting drum and the melt-extruded sheet using 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. 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 is not limited thereto. A method of using a plurality of casting drums and gradually 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. Furthermore, by reducing the thickness of the metal roll, the roll surface is slightly dented by the pressure applied when touched, and a roll called a flexible roll having a larger crimping area can be used.

  Further, touch roll film formation will be described with reference to FIG. In the present invention, as described above, it is more preferable that the melt 1 supplied from the extruder 3 is extruded from the die lip 4 and then formed on the casting drum 2 using the touch roll 5. In this method, the melt 1 exiting from the die is sandwiched between the casting drum 2 and the touch roll 5 and cooled and solidified. By using this, the fine unevenness formed on the above-described film can be smoothed, and blurring of an image can be reduced when it is incorporated in a liquid crystal display device. As such a touch roll, it is preferable to use one having elasticity in order to reduce residual strain generated when the melt discharged 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 It is 0.2 mm-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 preferably 100 nm or less, more preferably 50 nm or less, and further 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 it 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 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. It is preferable to set the temperature of a touch roll to 60 to 160 degreeC, More preferably, it is 70 to 150 degreeC, More preferably, it is 80 to 140 degreeC. Such temperature control can be achieved by passing a temperature-controlled liquid or gas through these rolls.

[Stretching process]
The cellulose ester film formed into a film in the melt film-forming step may be used without being stretched or may be used after being stretched.
When extending | stretching, you may extend | stretch as a process continuous from the film forming process, and after extending | stretching once in roll shape after film forming, you may extend | stretch. 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.). Tg here is the glass transition temperature of the stretched cellulose ester film. The stretching is preferably performed at least in one direction by -10% to 50%. The stretch ratio is more preferably -5% to 50%, still more preferably -3% to 45%, and 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.
Stretch ratio (%) = 100 × {(Length after stretching) − (Length before stretching)} / Length before stretching Such stretching is performed by 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 may be performed by gripping both ends of the film with a chuck and expanding it in the orthogonal direction (longitudinal direction and perpendicular direction) (lateral stretching). ). Moreover, you may relax after extending | stretching.

[Winding]
The sheet thus obtained is preferably trimmed at both ends and wound up. The trimmed part is re-processed as a raw material for film of the same kind or as a raw material for film of a different kind after being pulverized, or after being subjected to granulation, depolymerization, or re-polymerization 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, a cemented carbide blade or a ceramic blade is preferable because it has a long blade life and suppresses generation of chips. 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. Thus, the cellulose ester film manufactured through the melt film-forming process has a feature that the residual solvent amount (organic solvent content) is extremely low, and the residual solvent amount is 0.01% by mass or less. is there.

[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 is preferably saponified. The cellulose ester film used in the present invention may be subjected to surface treatment such as electron beam before or after 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, at the time of producing a polarizing plate, it is possible to produce a polarizing plate quickly and easily using a cellulose ester that has been saponified in advance.

[Releasable protective film]
(Basic structure)
The releasable protective film used in the present invention has a structure in which at least one pressure-sensitive adhesive layer is provided on one surface of at least one resin substrate. Furthermore, the release protective film used in the present invention may have a release sheet for protecting the adhesive surface on the pressure-sensitive adhesive layer, and this release sheet is used for adhesion to the cellulose ester film. Remove and stick.

(Resin base material)
As the resin substrate for forming the peelable protective film, a transparent plastic film is preferably used. By using a plastic film having transparency, it is possible to perform an appearance inspection of the optical component while the release protection film is adhered.
As the plastic film for the resin substrate, a polyester film such as polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, or polybutylene terephthalate is preferably used. In addition to the polyester film, other plastic films can be used as long as they have the necessary strength and have optical suitability. For example, polyimide, polystyrene, polyacrylonitrile, polymethacrylate, and the like can also be used. The resin base material is preferably polyethylene terephthalate, polyethylene naphthalate, polyethylene, or polypropylene.
The resin substrate may be an unstretched film or a uniaxial or biaxially stretched film. Moreover, the plastic film which controlled the angle of the axis | shaft method formed with the draw ratio and crystallization of extending | stretching may be used.
Although the thickness of the resin base material is not particularly limited, it is, for example, about 12 to 100 μm, and particularly about 20 to 50 μm in many cases. If necessary, the base film may be provided with an antifouling layer intended to prevent surface contamination, an antistatic layer, or a hard coat layer for preventing scratches on the opposite side of the adhesive layer. Alternatively, easy adhesion treatment such as corona discharge treatment or anchor coating treatment may be performed.

(Adhesive layer)
The pressure-sensitive adhesive layer is a layer formed on the surface of the resin base material, exhibits adhesiveness to the surface of the cellulose ester film, and remains on the resin base material when the releasable protective film is peeled off from the cellulose ester film. It is a layer with properties. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is selected from materials having such functions.
The pressure-sensitive adhesive layer preferably contains a pressure-sensitive adhesive containing a quaternary substituted ammonium salt or pyridium salt, an acrylic polymer having a hydroxyl group, and polyisocyanate.
As the acrylic polymer having a hydroxyl group, a polymer obtained by copolymerizing a monomer component having a hydroxyl group such as hydroxyethyl methacrylate together with a monomer such as an acrylic ester or methacrylic ester can be used.

  Quaternary substituted ammonium salts are cationic antistatic agents. Among the quaternary substituted ammonium salts, it is preferable to use one in which one alkyl group and three methyl groups are bonded to the nitrogen atom. Examples of such anions of alkyltrimethylammonium salts include chloride ions (alkyltrimethylammonium chloride).

  Although the kind of alkyltrimethylammonium salt is not particularly limited, it is particularly preferable that the alkyl group has 8 to 18 carbon atoms. Examples of the alkyl group include linear aliphatic hydrocarbon groups such as octyl group, decyl group, dodecyl group (lauryl group), tetradecyl group, hexadecyl group, octadecyl group (stearyl group), oleyl group and the like. More preferably, the alkyl group of the alkyltrimethylammonium salt has 8 to 12 carbon atoms, and specific examples include an octyl group, a decyl group, and a dodecyl group.

  When the alkyltrimethylammonium salt is used, the alkyltrimethylammonium salt contained in the pressure-sensitive adhesive can be bleed out on the adherend. Further, when the alkyl group has 8 to 18 carbon atoms, the adhesive strength of the pressure-sensitive adhesive and the antistatic performance imparted to the optical component by appropriate bleed-out of the alkyltrimethylammonium salt are optimized. That is, when the alkyl group has 7 or more carbon atoms, the alkyltrimethylammonium salt does not excessively bleed from the pressure-sensitive adhesive layer and tends to control the adhesive force. Moreover, if the alkyl group has 18 or less carbon atoms, there is little risk of insufficient bleed of the alkyltrimethylammonium salt, and the desired performance tends to be obtained.

  The origin of the alkyltrimethylammonium salt is not particularly limited. For example, a quaternized aliphatic amine derived from a fatty acid contained in a natural oil (such as vegetable oil or animal oil) is used. be able to. Alkyltrimethylammonium salts derived from natural fats and oils generally contain a plurality of types of alkyltrimethylammonium molecules having different alkyl group lengths. In order to suppress the total content of alkyltrimethylammonium salt, it is preferable to use an alkyltrimethylammonium salt derived from one source. As a result, the molecular weight distribution of the alkyltrimethylammonium salt can be reduced, and the time for the alkyltrimethylammonium salt to bleed out can be easily controlled. As a result, the total content of the alkyltrimethylammonium salt can be reduced. When the releasable protective film is used for short-term surface protection, such as in the manufacturing process of optical parts, it is covered between the time when it is attached to the surface of the optical part and the time when it is peeled off. Since it is preferable that a sufficient amount of alkyltrimethylammonium salt for preventing the surface of the adherend is bleed out, it is preferable to select and use an alkyltrimethylammonium salt having a relatively high bleed speed.

  On the other hand, in the present invention, plural kinds of alkyltrimethylammonium salts having different origins can be blended and used. By blending multiple types of alkyltrimethylammonium salts and increasing the molecular weight distribution of the alkyltrimethylammonium salts, the alkyltrimethylammonium salts gradually bleed out over time, allowing bleedout to continue for a longer period of time. Can be made. The type and blending ratio of the alkyltrimethylammonium salt can be selected depending on the miscibility with the pressure-sensitive adhesive. Examples of the salt include iodine ion, bromine ion, nitrate ion, sulfate ion, acetate ion, and the like, in addition to the above-described chlorine ion, preferably chloride ion, iodine ion, and acetate ion.

  Next, a pyridium salt will be described. Examples of the pyridium salt include alkyl-substituted vinyl pyridium. Those in which the alkyl group has 1 to 18 carbon atoms are preferred. Alkyl groups include methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, decyl, dodecyl (lauryl), tetradecyl, hexadecyl, octadecyl (stearyl) ), A linear aliphatic hydrocarbon group such as an oleyl group. More preferably, a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group, a heptyl group, an octyl group, etc. are mentioned. Examples of the salt include iodine ion, bromine ion, nitrate ion, sulfate ion, acetate ion and the like, preferably chlorine ion, iodine ion, acetate ion and the like in addition to the above-described chlorine ion.

  Next, polyisocyanate will be described. Polyisocyanate is a compound having a plurality of isocyanate groups (NCO groups) in the molecule. In particular, self-emulsifying polyisocyanates having self-emulsifying properties are preferred. Also preferred are polyisocyanates in which the isocyanate groups are three-dimensionally protected by hydrophobic groups. More specifically, it is preferable that the polyisocyanate is mixed with water having a mass ratio of about 5 to 9 times and the time until the NCO group disappears at room temperature (NCO group remaining time) is 5 to 7 hours. Such a polyisocyanate can be produced, for example, by the method described in Japanese Patent No. 3089623. Specific examples of the polyisocyanate include Aquanate Series (registered trademark) manufactured by Nippon Polyurethane Industry Co., Ltd.

  The ratio of the preferred alkyltrimethylammonium salt to the total amount of the pressure-sensitive adhesive is preferably in the range of 0.01 to 5 parts by weight, more preferably 0.1 to 1.5 parts by weight, with respect to 100 parts by weight of the pressure-sensitive adhesive. 0.3-1.2 mass parts is especially preferable. When the content of the alkyltrimethylammonium salt is too small, the peel charge amount cannot be made sufficiently small. On the other hand, when the proportion of the alkyltrimethylammonium salt is excessively large, the peel charge amount can be made small. Even if it can be done, the surface of the optical film used as a to-be-adhered body may be contaminated excessively, or it may be difficult to control the adhesive force.

(Production method)
The releasable protective film can be produced by providing a pressure-sensitive adhesive layer made of the above-mentioned pressure-sensitive adhesive on one side of the resin base material. That is, in the present invention, a conductive alkyltrimethylammonium salt is preferably used as the antistatic agent, and an acrylic polymer having a hydroxyl group is used as the pressure-sensitive adhesive. Even if the pressure-sensitive adhesive layer containing an agent is formed, a releasable protective film that exhibits excellent conductivity can be produced without deteriorating surface contamination.

  Formation of the pressure-sensitive adhesive layer containing the antistatic agent is performed by preparing a composition in which an organic solvent is mixed with the pressure-sensitive adhesive component containing the acrylic polymer, the alkyltrimethylammonium salt, and the polyisocyanate as necessary. What is necessary is just to apply | coat an object on a base film by coating means, such as gravure coating, Mayer bar coating, air knife coating, doctor knife coating, and reverse coating, and then, to dry. The pressure-sensitive adhesive layer is preferably a slightly pressure-sensitive adhesive layer having a light adhesiveness with a peel strength with respect to the surface of the adherend of about 0.03 to 0.3 N / 25 mm. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably about 5 to 40 μm, particularly about 10 to 30 μm.

  If necessary, the pressure-sensitive adhesive layer can be coated with a release sheet. The release sheet is not particularly limited, and examples thereof include those obtained by imparting peelability to the surface of a film such as a polyester film using a release agent such as a silicone-based release agent.

(Conductivity)
In the releasable protective film having the above-described configuration, by providing a pressure-sensitive adhesive layer containing a conductive material, the conductivity of the pressure-sensitive adhesive layer is controlled to 10 ¹² Ω or less at 25 ° C. and a relative humidity of 40%. ing.
Here, the electroconductivity of this invention shows the electrical resistance of the adhesive layer, and can be evaluated by the following procedures. That is, first, a sample is cut into a width of 1 cm and a length of 5 cm, and silver paint is uniformly applied to both ends in the length direction, and then humidity is adjusted for 3 hours in an environment of temperature and humidity as desired. After that, electrodes are applied to both ends of the silver coating layer, the resistance between the electrodes is determined at a voltage of 100 V, and converted to 1 cm, and the resistance of the conductive layer is obtained.

The conductivity of the pressure-sensitive adhesive layer is preferably 10 ^11.5 Ω or less, more preferably 10 ¹⁰ Ω or less, and particularly preferably 10 ^9.5 Ω or less in an environment of 25 ° C. and relative humidity 40%. Further, it is particularly preferable that it has conductivity even in a low humidity region, preferably 10 ¹² Ω or less, more preferably 10 ^11.5 Ω or less, more preferably 10 in an environment of 25 ° C. and 10% relative humidity. ¹⁰ Ω or less, particularly preferably 10 ^9.5 Ω or less. In the present invention, by producing a cellulose ester film laminate provided with a conductive releasable protective film, the release voltage when peeling the releasable protective film from the cellulose ester film laminate is 25. Under an environment of 60 ° C. and a relative humidity of 60%, preferably −1.0 kV to +1.0 kV, more preferably −0.7 kV to +0.7 kV, further preferably −0.5 kV to +0.5 kV, particularly preferably −0. .1 kV to +0.1 kV. Furthermore, it is particularly preferable to have conductivity even in a low humidity region, and the stripping voltage is preferably −1.0 kV to +1.0 kV, more preferably −0.7 kV even in an environment of 25 ° C. and a relative humidity of 10%. ˜ + 0.7 kV, more preferably −0.5 kV to +0.5 kV, and particularly preferably −0.1 kV to +0.1 kV. The peeling voltage can be adjusted by the type and content of the conductive agent contained in the pressure-sensitive adhesive layer. In addition, the peeling voltage in this application means the electric potential difference between the mold release protective film surface and the cellulose ester film surface produced when peeling a mold release protective film from a cellulose ester film.

  In the above-mentioned releasable protective film, an acrylic polymer having a hydroxyl group is used as the pressure-sensitive adhesive, and in addition to curing this pressure-sensitive adhesive with polyisocyanate, the pressure-sensitive adhesive includes an alkyltrimethylammonium salt as a conductive agent. Are particularly preferred. In the case of adopting this aspect, the peeling voltage at the time of peeling off the releasable protective film from the optical film is sufficiently low and the contamination of the adherend surface is less. In addition, there is an advantage that the number of coating films formed on the base film can be reduced to one.

(Lamination with cellulose ester film)
In the present invention, in order to laminate the releasable protective film on the cellulose ester film, the cellulose ester film and the releasable protective film are brought into contact with each other at an appropriate pressure while preventing air from being trapped. It is preferable to laminate by the adhesiveness which has. 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, a nip roll that combines a rubber roll and a rubber roll, etc., for example, the cellulose ester film and the releasable protective film are brought into a Y shape, and both of them are partially along the nip roll. It can be laminated by joining them together. It is preferable that the dispersion | variation in the thickness of the cellulose-ester film laminated body which laminated | stacked the mold release protective film on the cellulose-ester film is 3 micrometers or less.

The widths of the cellulose ester film and the releasable 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 releasable protective film is preferably 1: 0.1 to 1: 1.1, and preferably 1: 1.05 to 1: 1.1. It is more preferable that the ratio is 1: 0.8 to 1: 1.0. By setting the ratio of the width of the cellulose ester film to the width of the releasable protective film within a preferable range, advantageous effects can be obtained in terms of film sticking properties and transportability.
It is preferable that the peeling force required to peel both from the laminate of the releasable 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 likely to occur when peeling, and it is easy to peel off.

  In the present invention, the above-described releasable protective film is used by being adhered to the surface of a cellulose ester film. The cellulose ester film is used for optical components such as a polarizing plate, a retardation plate, and a polarizing plate that also serves as a retardation plate. In addition, the cellulose ester film is incorporated in an optical system device such as a liquid crystal display device or various instruments and used as a part thereof. The releasable protective film may be peeled off before the cellulose ester film is used in these optical parts and optical system devices, or peeled off after being applied to these optical parts and optical system devices without peeling. May be. According to the present invention, even when peeling after application to an optical component or an optical system device, the peeling charge is suppressed to be sufficiently small, so that circuit components such as driver ICs, TFT elements, and gate line driving circuits are destroyed. The reliability of a device such as a liquid crystal display panel can be maintained.

[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)
It is preferable that the residual solvent amount of the cellulose ester film which comprises the laminated body of this invention is 0.01 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, streaky light leakage is not 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 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 cellulose ester film 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 cellulose ester film 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 cellulose ester film constituting the cellulose ester film laminate of the present invention preferably has a front retardation (Re) at a wavelength of 590 nm of 0 to 300 nm, and a thickness direction retardation (Rth) of -300 to 700 nm. Preferably there is. 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.

  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 used in the present invention is produced by melt film formation, so that the difference between the optical properties of 10% relative humidity and 80% optical properties at 25 ° C. is preferably 15 nm or less, more preferably 10 nm or less, Preferably, it can be 8 nm or less. 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 cellulose ester film 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 3%, more preferably 0 to 2%, still more preferably 0 to 1.5%, particularly Is preferably 0.05 to 0.8%. From the above viewpoint, the cellulose ester film constituting the cellulose ester film laminate of the present invention has a haze of 0.05 to 1.2%, a visible light transmittance of 91% or more, and 25 ° C./relative humidity. 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 in a 60% environment.

[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 film), 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.

[Polarizer]
(Applying polarizing film)
A polarizing film can be imparted to the cellulose ester film constituting the cellulose ester film 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. The iodine and the dichroic dye in the polarizing film develop 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.

(Layer structure of polarizing plate)
The following are mentioned as a layer structure of a polarizing plate.
B) A / P / A
B) A / P / B
C) A / P / T
D) B / P / B
E) B / P / T
Here, “A” is a cellulose ester film constituting the cellulose ester film 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 (for example, Fuji Fujitac TD80UL (film thickness 80 μm), Fujitac T80UZ (film thickness 80 μm) and Fujitac T40UZ (film thickness 40 μm) manufactured by Photo Film Co., Ltd., KC8UX2M (film thickness 80 μm), KC5UX manufactured by Konica Minolta Holdings, Inc. (Film thickness 57 μm), KC4UX2M (film thickness 40 μm), KC8UN (film thickness 80 μm), KC8UY (film thickness 80 μm, KC4UY (film thickness 40 μm), KC8UX-H, 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 of them may be used as a liquid crystal surface, but in the case of configurations b) and 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 a liquid crystal is usually disposed between two polarizing plates. In this case, the polarizing plates of the present invention (i) to (e) and normal polarized light. 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.

[Antireflection film]
(Structure 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 cellulose ester film 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 the low refractive index layer <Refractive index of the transparent support <Refractive index of the intermediate refractive index layer <Refractive index of the 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.
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 deterioration of the transmitted image.

[Optical compensation film]
The unstretched or stretched cellulose ester film constituting the cellulose ester film 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.

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

(General liquid crystal display 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 the optical compensation sheet, it is preferable to arrange the transmission axis of the polarizing element (described later) and the slow axis of the optical compensation sheet made of the 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.

(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 in 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) Synthesis of cellulose ester A 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), it was stored at room temperature for 1 hour (pretreatment). 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. The reaction solution was sequentially filtered under pressure with a sintered metal filter having a reserved particle size of 40 μm, 10 μm, and 5 μm to remove foreign matters. To the filtered reaction solution, 6.2 parts by mass of a mixed solution of magnesium acetate tetrahydrate, acetic acid and water in equal masses was added and stirred for 30 minutes.

The magnesium acetate reaction solution 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 powder was dried at 70 ° C. to obtain cellulose ester A. ^From the measurement of ¹ H-NMR, cellulose ester A had an acetyl group substitution degree of 0.15, a propionyl group substitution degree of 2.55, a weight average molecular weight of 135,000 and a number average molecular weight of 52,000. The precipitation process and the drying process after the filtration process were performed under environmental conditions of class 2000 or less. All solvents and water used were fluororesin cartridge filters (Clanfill KF2L10 (pore size 10 μm, Kurashiki Spinning Co., Ltd.)) and fluororesin cartridge filters (Clanfill KF2L10 (pore size 1 μm, Kurashiki Spinning Co., Ltd.)). The thing from which the foreign material was removed was used in order.

(2) Pelletization After the cellulose ester A was dried at 105 ° C. for 5 hours to have a water content of 0.07% by mass, silica fine particles having a primary average particle size of 20 nm with respect to the solid content of the cellulose ester A were reduced to 0.000. 007 mass%, UV agent a as an ultraviolet absorber: {2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine } 0.2% by mass, UV agent b: 0.2% by mass of {2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole}, and UV agent c: 0.2% by mass of {2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole}, UV agent d: 2, 2′-methylenebis [4- (1,1,3,3- Tramethylbutyl) -6-[(2H-benzotriazol-2-yl) phenol]] (ADK STAB LA-31, manufactured by ADEKA Corporation) 0.7 mass%, plasticizer a: 2 mass of biphenyl diphenyl phosphate %, Plasticizer b: 2% by mass of trimethylolpropane tribenzoate, plasticizer c: 2% by mass of ethylfurylethyl glycolate, plasticizer d: 2% by mass of triacetyltripropionyl sorbitol, plasticizer e: phosphoric acid type 2% by mass of ester (Adeka Stab FP-700, manufactured by ADEKA), 2% by mass of plasticizer f: polymethyl methacrylate (average molecular weight 5000), bis (2,6-di-tert-butyl-4 as a stabilizer -Methylphenyl) pentaerythritol di-phosphite 0.1% by weight, 2,2′-methylenebis [4- ( , 1,3,3-tetramethylbutyl) -6-[(2H-benzotriazol-2-yl) phenol]], 0.1% by weight, bis [(1,2,2,6,6-pentamethyl- 4-piperidinyl) 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butyl malonate 0.1% by mass, Adeka Stab AO-80 (ADEKA Corporation) 0.05 % By mass, 0.05% by mass of ADK STAB PEP36Z (ADEKA), 0.05% by mass of ADK STAB AO-412S (ADEKA), 0.05% by mass of ADK STAB CDA-6 (ADEKA), ADK STAB LA-63P (ADEKA) 0.05% by mass, Adeka Stub D-32 (ADEKA) 0.05% by mass, Adeka Sizer O-130P ( 0.05% by mass of ADEKA), 0.05% by mass of Adekasizer O-180A (ADEKA), 0.01% by mass of aluminum stearate, 0.01% by mass of zinc behenate, and smirrazer 0.15% by mass of GP (manufactured by Sumitomo Chemical Co., Ltd.), tridecafluoroethyl methacrylate / poly (average polymerization degree 5) oxyethylene methacrylate / butyl acrylate = 30/20/50 (molar ratio, molecular weight 9000) as a release agent Was added in an amount of 0.1 mass%, and further, 0.00005 mass% of 1,4-bis (2,4,6-tripropylcyclohexylsulfonamidophenyl) anthraquinone was added as a dye.

  After the addition, it was mixed in a Henschel mill. The number of rotations was 100 rpm to 1000 rpm, and mixing was performed at a temperature of 20 to 80 ° C. for 30 minutes. The mixture was dried at 105 ° C. for 3 hours until the water content of the obtained mixture was 0.1% by mass or less. Thereafter, the mixture was put into a hopper of a twin-screw kneading extruder, and kneaded and melted at 150 to 200 ° C. with a screw rotation speed of 300 rpm and a residence time of 40 seconds. This was extruded from a die at a rate of 500 kg / hour into a strand having a diameter of 3 mm, immersed in a pure water bath at 60 ° C. through a 0.5 μm filter for 0.5 minutes (strand solidification), and then a 0.5 μm filter. The temperature was lowered by passing it through pure water at 20 ° C. for 30 seconds, exposed to the air and conveyed for 4 m, and then cut into a length of 3 mm to obtain a pellet. The obtained pellets made of cellulose ester A were dried at 105 ° C. for 2 hours, and then packed in a moisture-proof bag made of a laminate film having aluminum and stored. In addition, this process was implemented on the environmental conditions of class 2000 or less, and the space where cellulose ester A touches air was made into the environmental conditions of class 1000 or less.

(3) Film formation The pellets of cellulose ester A were dried in a vacuum dryer at 110 ° C. for 3 hours. This was put into a hopper and melted at 225 ° C., and then a sintered metal filter having a diameter of 20 μm and a sintered metal filter having a diameter of 10 μm were continuously used and pressure filtered at a rate of 0.1 m / min at 10 MPa. It was confirmed that the obtained filtrate had a transparent and homogeneous composition.
This was put into a hopper adjusted to 190 ° C., melted at 230 ° C., and kneaded and melted at L (screw length) / D (screw diameter) = 30 using a full flight screw with a compression ratio of 3.5. . Further, 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 and implemented in JP-A-11-235747. Using the touch roll described in Example 1, a film was formed at a touch pressure of 0.3 MPa. This was peeled off from the casting roll and wound up. In addition, after trimming both ends (each 3% of the full width) just before winding, after applying thickness processing (knurling) with a width of 10 mm and a height of 50 μm at both ends, it is wound into a roll of 3000 m with a width of 1.6 m A cellulose ester film A was prepared. When the residual solvent amount of this film was measured by gas chromatography, it was 0.01% by mass or less. In addition, this process was implemented on the environmental conditions of class 1000 or less under clean air.

(4) Adhesion of releasable protective film As a conductive agent, alkyltrimethylammonium chloride (trade name: Electro Stripper QN manufactured by Kao Corporation), which is an alkyltrimethylammonium salt, and an acrylic adhesive (Nippon Carbide Industries, Ltd.) Product, product name: SZ-2242 developed product) and polyisocyanate curing agent (manufactured by Nippon Polyurethane Industry Co., Ltd., product name: Aquanate AQ-200), solids of antistatic agent, adhesive and curing agent The mixture was blended so that the mass ratio of the components was 1: 100: 3, and diluted and dissolved in toluene (20% by mass) to prepare an adhesive diluted solution. After activating one side of a 38 μm thick biaxially stretched polyester film (biaxially stretched polyethylene terephthalate film) as a resin base material by irradiation with vacuum glow, the pressure-sensitive adhesive diluted solution is made to have a thickness of 15 μm on a dry basis. The pressure-sensitive adhesive layer containing a conductive agent was formed by coating and drying, and a releasable protective film A was produced. The conductivity on the adhesive layer side is 1.5 × 10 ¹⁰ Ω at 25 ° C. and 40% relative humidity, and 0.5 × 10 ¹² Ω at 25 ° C. and 10% relative humidity. Was shown. Furthermore, a release sheet made of a polyester film subjected to silicone treatment was coated on the pressure-sensitive adhesive layer. As described above, a releasable protective film AH with a release sheet having a layer configuration of “resin base material / adhesive layer / release sheet” was obtained.

(5) Production of Cellulose Ester Film Laminate One side of the cellulose ester film A produced above (the releasable protective film A) was obtained by peeling and removing the release sheet from the release protective film AH with the release sheet. Using a nip roll made of a combination of a rubber roll and a metal roll on the casting roll surface side), the casting roll surface side of the cellulose ester film and the peelable protective film A are brought into a Y shape, and the nip roll In a state in which both of them were partially along, they were laminated and bonded to obtain a cellulose ester laminate 1-1. 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. Here, this process was performed under clean air under environmental conditions of class 1000 or less. In the releasable protective film A after removing the release sheet, the conductivity on the pressure-sensitive adhesive layer side is 1.6 × 10 ¹⁰ Ω at 25 ° C. and a relative humidity of 40%, and 25 ° C. and a relative humidity of 10 % Was 0.6 × 10 ¹² Ω, and no change in conductivity was observed, confirming that excellent conductivity was maintained.

(6) Evaluation of Cellulose Ester Film Laminate The film wound on the roll-shaped core of the cellulose ester film laminate 1-1 obtained by the above-described method is pulled out again at a speed of 30 m / min to release the film. The protective film A was peeled off. Here, peeling of the releasable protective film A was carried out by winding the releasable protective film around a winding core along the conveyance path of the cellulose ester film laminate sample 1-1.

  In addition, this process was implemented on the environmental conditions of 25 degreeC and 60% of relative humidity which were made into the class 1000 or less by the downflow type clean air. When the voltage generated with an electrometer (Trek Japan Co., Ltd., MODEL 344) at the time of peeling was measured, the peeling voltage was about 0.3 kV on average. Further, no abnormal noise was observed between the peeled surfaces at the time of peeling, and the peeling was performed smoothly. In addition, the releasable protective film A is not observed to be adhered to the cellulose ester film A due to static electricity, and is not smoothly transported to the rewinding roll of the releasable protective film, and is smoothly wound. confirmed.

  The cellulose ester film A obtained by peeling off the releasable protective film A was sandwiched between two orthogonal polarizing films, and light leakage caused by scratches and foreign matters observed visually was observed. Leakage was not observed at all, and it was confirmed that the cellulose ester film had an excellent surface shape. Further, in the observation of bright spot foreign matter described later, the number of bright spot foreign matters of 10 μm or more was 2/3 m. Moreover, it was confirmed that these bright spot foreign materials were 20 μm or less. Furthermore, after the cellulose ester film laminate 1-1 (20 cm × 20 cm square, 2 sheets) of the present invention was conditioned for 3 hours in an environment of 25 ° C. and 10% relative humidity, the two sheets were put together. Then, after applying a load of 2 kg to the whole and rubbing the front and back 10 times, the ash of tobacco was brought close to 1 cm on each friction surface of the two cellulose ester film laminates 1-1 and the adhesion was examined. As a result, no adhesion of tabaque ash was observed. In addition, in the static electricity measurement from the friction surface at that time, it was 0.2 kV or less and showed a sufficiently small value.

  Here, the cellulose ester film A obtained by peeling the releasable protective film from the cellulose ester film laminate 1-1 of the present invention exhibits the following characteristics and is an excellent optical substrate. confirmed. 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.

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%. The curl value was -0.11 at a relative humidity of 25% and 1.3 at 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. As for the bright spot, 0.02 mm or less was less than 2/3 m, 0.02 to 0.05 mm was less than 1/3 m, and 0.05 mm or more was not found. Therefore, it was confirmed that it has excellent characteristics for optical applications. Moreover, the adhesiveness after application was A, and the moisture permeability was also good (610 g / m ² · day). The residual solvent amount was 0.01% by mass or less.

(7) Measuring method and evaluation method It describes about the measuring method and evaluation method of the above-mentioned each characteristic regarding the cellulose-ester film which is a board | substrate of a cellulose-ester film laminated body below.

(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)
The film was conditioned at 25 ° C. and 60% relative humidity for 24 hours, then using a prism coupler (MODEL2010 Prism Coupler: manufactured by Metricon), and at 25 ° C. and 60% relative humidity, using a 532 nm solid laser, the following formula (a The average refractive index (n) represented by
Formula (a): n = (n _TE × 2 + n _TM ) / 3
[ _Where n _TE is a refractive index measured with polarized light in the film plane direction, and n _TM is a refractive index measured with polarized light in the film surface normal direction. ]
Re was measured with KOBRA 21ADH or WR (both manufactured by Oji Scientific Instruments) with light having a wavelength of λ nm incident in the normal direction of the film. Rth (λ) was calculated by the following procedure <1> or <2>.
<1> When a film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid Rth is an in-plane slow axis (determined by KOBRA 21ADH or WR) and a tilt axis (rotation) Axis) (in the case where there is no slow axis, the rotation axis is an arbitrary direction in the film plane), from the film normal direction to −50 ° to + 50 °, each in a 10 ° step, the wavelength from the inclined direction is 590 nm. In total, 11 retardation values were measured, and KOBRA 21ADH or WR was calculated based on the measured retardation value, average refractive index, and input film thickness value.
Here, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value was calculated by KOBRA 21ADH or WR after changing its sign to negative.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (when there is no slow axis, the arbitrary direction in the film plane is the rotation axis), Based on the value, the average refractive index, and the input film thickness value, Rth can also be calculated from the following formulas (b) and (c).

式（ｂ）：
［式中、Ｒｅ（θ）はフィルム法線方向から角度θ傾斜した方向におけるレタ−デーション値を表す。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
＜２＞ 測定されるフィルムが１軸や２軸の屈折率楕円体で表現できないものである場合［いわゆる光学軸（optic axis）がないフィルムの場合］
Ｒｔｈは、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°から＋５０°まで１０°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点のレターデーション値を測定し、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が算出した。
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がｎｘ、ｎｙ、ｎｚを算出した。この算出されたｎｘ、ｎｙ、ｎｚよりＮｚ＝（ｎｘ−ｎｚ）／（ｎｘ−ｎｙ）をさらに算出した。

Formula (b):
[In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the film 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
<2> When the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid [in the case of a film having no so-called optic axis]
Rth is the direction in which the slow axis (indicated by KOBRA 21ADH or WR) in the plane is inclined with respect to the normal direction of the film from −50 ° to + 50 ° in 10 ° steps. Then, 11 points of retardation values were measured by making light having a wavelength of 590 nm incident thereon, and KOBRA 21ADH or WR was calculated based on the measured retardation values, average refractive index, and input film thickness value.
By inputting these average refractive index and film thickness, KOBRA 21ADH or WR calculated nx, ny, and nz. Nz = (nx−nz) / (nx−ny) was further calculated from the calculated nx, ny, and nz.

(Re unevenness, Rth unevenness)
Sampling was performed at intervals of 1 m in the longitudinal direction at a sampling point of 100 points and a size of 1 cm square, and was sampled at an equal interval of 5 cm in a size of 1 cm square over the entire width of film formation. The difference between each maximum value and the minimum value of the obtained samples was determined and used as Re unevenness and Rth unevenness.

(Thickness unevenness)
Sampling was performed at intervals of 1 m in the longitudinal direction at a sampling point of 100 points and a size of 1 cm square, and was sampled at an equal interval of 5 cm in a size of 1 cm square over the entire width of film formation. 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)
Re (10% RH) and Rth (10% RH) were determined at 25 ° C./relative humidity 10%. Further, 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 Re humidity dependence, 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%.

(Molecular orientation axis)
Sample 70mm x 100mm was conditioned at 25 ° C and relative humidity 65% for 2 hours, and the phase difference when 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.

(Tensile strength, elongation rate)
About the length direction of the film, about 5 m from the film winding point, 1/4 of the full length, 1/2 of the full length, 3/4 of the full length, and 5 m from the final winding end Each sample 15 mm × 250 mm was conditioned at 23 ° C. and 65% relative humidity for 2 hours, and tensioned with a Tensilon tensile tester (Orientec Co., Ltd., RTA-100) according to ISO 1184-1983. The elastic modulus was calculated from the initial tensile stress and elongation at a speed of 200 ± 5 mm / min, and the tensile strength and elongation force were determined.

(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 at 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.

(Heat shrinkage)
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 a thermostat at 80 ° C ± 1 ° C and heat-treated for 3 hours. After conditioning in a room at 23 ± 3 ° C and relative humidity 65 ± 5% for 3 hours or more, the sample was heat-treated 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, light leakage was observed with an optical microscope (50 times) from the opposite side, and its size (maximum length) and number were observed to make a bright spot foreign material.

(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 on 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 were overlaid and sealed in a moisture-proof bag when the film was melted. 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 relative humidity 60%, 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 at 25 ° C. for the number of seconds to drop, 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 . ]

(Alkaline hydrolyzable)
A sample 100 mm × 100 mm was saponified for 3 minutes with an automatic alkali saponification apparatus (manufactured by Shinto Kagaku Co., Ltd.) using a 2 mol / L sodium hydroxide aqueous solution at 60 ° C., washed with water for 4 minutes, and then washed at 30 ° C. 0.01 mol / L dilute nitric acid was added to neutralize 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 the Karl Fischer method using a moisture meter 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.

(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, and the elastic modulus was determined.

(Fine irregularities)
The film sample 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. Further, the height means the height in the vertical direction from the average line of the surface unevenness, and the depth means the depth in the vertical direction from the average line of the surface unevenness. 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.

[Comparative Example 1]
Comparative sample 1-1 was prepared in exactly the same manner as in Example 1, except that the peelable protective film A was not adhered in Example 1 (5), except that the cellulose ester film was in the winding roll state. did. At this time, the conductivity on the pressure-sensitive adhesive layer side of the obtained cellulose ester film was 1 × 10 ¹⁵ Ω or more at 25 ° C. and 10% relative humidity, and did not show conductivity. Further, it was 5 × 10 ¹⁴ Ω or more at 25 ° C. and 40% relative humidity, and 1 × 10 ¹³ Ω or more at 25 ° C. and 70% relative humidity, and the conductivity was not improved even at high humidity.
The film in which the obtained cellulose ester film of Comparative Sample 1-1 was wound around a roll core was pulled out again at a speed of 30 m / min. This process was carried out under the environmental conditions of 25 ° C. and 60% relative humidity with a down-flow type clean air of class 1000 or lower. Peeling of the peelable protective film C was performed by winding around a winding core along the transport path of the cellulose ester film laminate. When the voltage generated by an electrometer at the time of peeling (Trek Japan Co., Ltd., MODEL 344) was measured, the peeling voltage was about 5.4 kV on average. When the obtained cellulose ester film of Comparative Sample 1-1 was sandwiched between two orthogonal polarizing films and observed for light leakage observed visually, 11 / m of light leakage of 30 μm or more was observed. It was the level which becomes a problem as a state.
Furthermore, after the comparative sample 1-1 (20 cm × 20 cm square, 2 sheets) was conditioned for 3 hours in an environment of 25 ° C. and a relative humidity of 10%, the load of 2 kg was applied to the entire surface by combining the two sheets. After rubbed the front and back 10 times, the ash of tobacco was brought close to 1 cm on each friction surface of the two comparative samples 1-1 and the adhesion was examined. Attached. The static electricity measured from the friction surface at that time was 1.9 kV or more and had a large charge.
Comparing the results of Comparative Example 1 and Example 1, it is clear that the cellulose ester film laminate of the present invention in which the pressure-sensitive adhesive layer is conductive has excellent characteristics.

[Comparative Example 2]
In the adhesion of the release protective film (4) of Example 1, except that alkyltrimethylammonium chloride (trade name: Electrostripper QN, manufactured by Kao Corporation), which is an alkyltrimethylammonium salt as a conductive agent, is not added. In the same manner as in Example 1, a comparative releasable protective film A2H was produced, and using the cellulose ester film A, a comparative sample 2-1 of a cellulose ester film laminate was produced. The resulting conductive adhesive layer side of the comparison sample, be a 25 ° C. · Relative humidity is 40% for 1 × 10 ¹⁵ or more Omega, also 25 ° C. · Relative humidity 10% 1 × 10 ¹⁵ Omega more It did not show conductivity. Next, the film wound around the roll core of Comparative Sample 2-1 of the cellulose ester film laminate was pulled again at a speed of 30 m / min in exactly the same manner as the evaluation of the above (6) cellulose ester film laminate. The release protective film A2 was peeled off. Here, peeling of the releasable protective film A2 was performed by winding the releasable protective film around a winding core along the conveyance path of the cellulose ester film laminate sample 1-1.
In addition, this process was implemented on the environmental conditions of 25 degreeC and 60% of relative humidity which were made into the class 1000 or less by the downflow type clean air. When the voltage generated by an electrometer (Model 344, manufactured by Trek Japan Co., Ltd.) at the time of peeling was measured, the peeling voltage was around 6 kV on average, indicating a very large charge. In addition, abnormal noise was observed between the peeled surfaces during peeling, and peeling occurred while stick-slip. In addition, the releasable protective film A2 was adhered to the cellulose ester film A due to static electricity, irregular transport was generated on the take-up roll of the releasable protective film A2, and the releasable protective film A2 was not smoothly wound. As mentioned above, when not providing electroconductivity to a peelable protective film, it is a problem that the trouble of conveyance by static electricity generate | occur | produces, and it was confirmed that this invention is excellent.

[Comparative Example 3]
Example 4 (4) In place of the releasable protective film AH of the releasable protective film, except that the protective film (adhesive sheet) produced by the method described in Example 1 of JP 2000-273417 A is used. Produced a comparative sample 3-1 of a cellulose ester film laminate in exactly the same manner as in Example 1, and evaluated according to Example 1.

  The film wound around the roll core of Comparative Sample 3-1 was pulled out again at a speed of 30 m / min to peel off the releasable protective film. Here, peeling of the releasable protective film was carried out by winding the releasable protective film around a winding core along the transport path of the cellulose ester film laminate. The stripping voltage at that time was about 3.7 kV on average and was high. Further, abnormal noise was observed between the peeled surfaces during peeling. The releasable protective film did not show significant adhesion to the cellulose ester film due to static electricity, but irregular transport was occasionally observed on the take-up roll of the releasable protective film, and it was not smooth. .

Moreover, when the cellulose ester film obtained by peeling off the releasable protective film was sandwiched between two orthogonal polarizing films, light leakage caused by scratches and foreign matters observed visually was observed. Some leakage was observed.
Therefore, it is clear that the comparative peelable protective film provided with the conductive layer on the substrate and further provided with the pressure-sensitive adhesive layer is inferior in its charging property, and the present invention is excellent. it is obvious.

[Example 2]
Except that the following releasable protective film B was used in place of the releasable protective film A, the releasable protective film was attached in the same manner as in Example 1 and unwound again to form a releasable protective film. It peeled and the surface shape of the cellulose-ester film A was observed. The releasable protective film B used here is a releasable protective film produced by coextrusion in which the base material is PE and the pressure-sensitive adhesive layer is EVA (EVA) (base material layer 42 μm, pressure-sensitive adhesive layer 8 μm). . At this time, 1% by mass of octadecyltrimethylammonium chloride was added to EVA (EVA) of the pressure-sensitive adhesive layer with respect to EVA to impart conductivity. The conductivity of the pressure-sensitive adhesive layer side is 3.6 × 10 ¹⁰ Ω at 25 ° C. and 40% relative humidity, and 0.2 × 10 ¹² Ω at 25 ° C. and 10% relative humidity. showed that. Furthermore, a release sheet made of a polyester film subjected to silicone treatment was coated on the pressure-sensitive adhesive layer. As described above, a release protective film with release sheet BH having a layer structure of “resin base film / adhesive layer / release film” was obtained.
A film (releasable protective film B) from which the release sheet is peeled and removed from the releasable protective film BH with a release sheet is applied to one side (casting roll surface side) of the cellulose ester film A. Using a nip roll that is a combination of a rubber roll and a metal roll, the casting roll surface side of the cellulose ester film A and the releasable protective film B are brought into a Y-shape, and the nip roll is in a state where both of them are partially along the nip roll. The cellulose ester film laminate 2-1 was obtained by laminating by bonding. The thickness variation in the width direction and the longitudinal direction of the laminate was measured and found to be 2.4 μm and 0.6 μm, respectively. In addition, this process was implemented on the environmental conditions of class 1000 or less under clean air. The roll length of the obtained laminate was 2500 m.

The film wound around the roll core of the cellulose ester film laminate 2-1 obtained by the above-described method was pulled out again at a speed of 30 m / min, and the releasable protective film B was peeled off. Here, peeling of the releasable protective film B was performed by winding the releasable protective film B around a winding core along the conveyance path of the cellulose ester film laminate 2-1.
In addition, this process was a downflow type clean air, and was implemented on the environmental conditions of 25 degreeC and 60% of relative humidity which were set to class 1000 or less. When the voltage generated with an electrometer (Trek Japan Co., Ltd., MODEL 344) at the time of peeling was measured, the peeling voltage was about 0.3 kV on average. Further, no abnormal noise was observed between the peeled surfaces at the time of peeling, and the peeling was performed smoothly. In addition, the releasable protective film B has no adhesion to the cellulose ester film A due to static electricity, and the rewinding roll of the releasable protective film does not show irregular conveyance, and is smoothly wound. confirmed.

  The cellulose ester film A obtained by peeling off the releasable protective film B was sandwiched between two orthogonal polarizing films, and light leakage caused by scratches and foreign matters observed visually was observed. Leakage was not observed at all, and it was confirmed that the cellulose ester film had an excellent surface shape. Further, in the observation of bright spot foreign matter, the number of bright spot foreign matters of 10 μm or more was 3/3 m. Moreover, it was confirmed that these bright spot foreign materials were 15 μm or less.

  In addition, after the cellulose ester film laminate 2-1 (20 cm × 20 cm square, 2 sheets) of the present invention was conditioned for 3 hours in an environment of 25 ° C. and 10% relative humidity, the two sheets were put together. Then, after applying a load of 2 kg to the entire surface and rubbing the back and front 10 times, tobacco ash was brought close to 1 cm on each friction surface of the two cellulose ester film laminates 2-1, and the adhesion was examined. However, no adhesion of tabaque ash was observed. In addition, in the static electricity measurement from the friction surface at that time, it was 0.2 kV or less and showed a sufficiently small value.

[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 releasable protective film C in Example 1.
(1) Preparation of pressure-sensitive adhesive for use in an optical protective film An acrylic polymer composed of p-toluenesulfonate of 2-ethylhexyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate and trimethylammonium propyl methacrylate (mass ratio: 65 / 29/3/3, a mass average molecular weight of 300,000) 25% ethyl acetate solution, 3 parts by mass of trimethylolpropane tolylene diisocyanate is added to and mixed with 100 parts by mass of the acrylic polymer in terms of solid content. A pressure-sensitive adhesive composition was prepared. The conductivity on the adhesive layer side is 6.2 × 10 ¹⁰ at 25 ° C. and 40% relative humidity, and 0.8 × 10 ¹² Ω at 25 ° C. and 10% relative humidity. It was to show.

(2) Preparation of releasable protective film C On one side of a 38 μm thick polyethylene terephthalate film, the acrylic pressure-sensitive adhesive composition was applied with a wire bar so that the coating amount after drying was 0.04 g / m ^2. And dried at 20 ° C. for 1 minute to form an adhesive layer. Next, a release sheet made of a polyester film subjected to silicone treatment was coated on the opposite surface of the pressure-sensitive adhesive layer of the polyethylene terephthalate film. Thus, a peelable protective film C with a release sheet having a layer configuration of “resin base film / adhesive layer / release sheet” was obtained. At this time, the surface of the release protective film opposite to the adhesive layer was colloidal silica (primary particle system 20 nm) / polymethyl methacrylate (average molecular weight 150,000, 0.55 g / m ² ) on the glow-irradiated surface. Is applied to produce surface irregularities having a maximum convexity of about 0.05 μm.

(3) Evaluation of Cellulose Ester Film Laminate The film wound on the roll core of the obtained cellulose ester film laminate (cellulose ester film laminate sample 3-1) was pulled out again at a speed of 50 m / min. The peelable protective film C was peeled off. This process was carried out under the environmental conditions of 25 ° C. and 60% relative humidity with a down-flow type clean air of class 1000 or lower. Peeling of the peelable protective film C was performed by winding around a winding core along the conveyance path of the cellulose ester film laminate sample 3-1. When the voltage generated with an electrometer (Trek Japan Co., Ltd., MODEL 344) at the time of peeling was measured, the peeling voltage was about 0.2 kV on average. The cellulose ester film A obtained by peeling off the peelable protective film C was sandwiched between two orthogonal polarizing films, and light leakage caused by scratches and foreign matters observed visually was observed. No light leakage was observed in the cellulose ester film laminate (cellulose ester film laminate sample 3-1) to which the film was attached, and it was confirmed that the film had an excellent surface shape.

  Furthermore, after adjusting the cellulose ester film laminate 3-1 (20 cm × 20 cm square, 2 sheets) of the present invention for 3 hours in an environment of 25 ° C. and 10% relative humidity, the two sheets are put together. Then, after applying a load of 2 kg to the whole and rubbing the front and back 10 times, tobacco ash was brought close to 1 cm on each friction surface of the two cellulose ester film laminates 3-1, and the adhesion was examined. However, no adhesion of tabaque ash was observed. In addition, in the static electricity measurement from the friction surface at that time, it was 0.2 kV or less and showed a sufficiently small value.

[Example 4]
The cellulose ester A used in the production of the cellulose ester film laminate sample 1-1 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 acyl group). Powder having a degree of substitution of 2.90, a viscosity average degree of polymerization of 150, a water content of 0.1% by mass, a viscosity of 6% by mass in a dichloromethane solution of 52 mPa · s, an average particle size of 1.5 mm and a standard deviation of 0.5 mm. A laminate sample 4-1 of the present invention was produced in exactly the same manner as the cellulose ester film laminate sample 1-1 of Example 1 except that the sample was changed to (body). Further, cellulose ester A was converted to cellulose ester C (acetyl group substitution degree 1.00, propionyl group substitution degree 1.85, total acyl group substitution degree 2.85, viscosity average polymerization degree 160, water content 0.05 mass. %, A 6 mass% viscosity in a dichloromethane solution of 125 mPa · s, an average particle size of 1.0 mm, and a powder having a standard deviation of 0.25 mm), a cellulose ester film laminate sample 1 of Example 1 The laminate sample 4-2 of the present invention was produced in exactly the same manner as in -1. 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. Furthermore, in the above-described experiment of tobacco ash adhesion, no ash adhesion was observed, and the charged voltage was 0.2 kV or less, indicating excellent antistatic properties.

[Example 5]
Next, examples in which the cellulose ester film is applied to a polarizing plate and the like will be described.
(1) Preparation of polarizing plate (saponification of cellulose ester film)
Cellulose ester film A obtained by peeling peelable protective film A from cellulose ester film laminate 1-1 of the present invention, and separately N, N ′, N ″ -tri-m-toluyl-1,3,5 -Cellulose obtained by adding 4% by mass of triazine-2,4,6-triamine to the cellulose ester, casting the solution, and stretching 1.32 times in the width direction while drying in the presence of residual solvent Triacetate (Re is 60 nm, Rth is 200 nm, film thickness is 80 μm) was saponified by the following method: That is, KOH was dissolved to 1.5 mol / L and then adjusted to 60 ° C. as a saponification solution. was used. then, 10 g / m ² was coated on the 60 ° C. cellulose ester film was saponified for 1 minute. Thereafter, the spray of 50 ° C. warm water of 10 liters / Washed sprayed for one minute at ^2-min. Implementation then sends a 110 ° C. in dry air at wind speed 15 m / sec, and dried for 5 minutes. The saponification, while conveying the roll-shaped film at a rate of 45 m / min The saponified film of the cellulose ester film A obtained by peeling the peelable protective film A from the cellulose ester film laminate 1-1 of the present invention was designated as Sample 5-1, and the cellulose triacetate obtained by stretching. This saponified film was designated as TAC-5.

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

(Lamination)
The polarizing film thus obtained was sandwiched between the saponified cellulose ester film sample 5-1 and a saponified product of stretched cellulose triacetate film (TAC-5), and then PVA (manufactured by Kuraray Co., Ltd., PVA- 117H) Using a 3% 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 these, the cellulose ester film 5-1 according to the present invention and a separately prepared saponified cellulose triacetate film (TAC-5, Re is 61 nm, Rth is 205 nm) are described in FIGS. 2 to 9 of JP-A No. 2000-154261. After mounting to a 20-inch VA-type LCD 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 visually evaluated, and the ratio (%) at which it occurred was determined. The color change of the cellulose ester film A according to the present invention was 1, which was very excellent. Further, according to Example 1 of JP-A No. 2002-86554, the cellulose ester film A according to the present invention is similarly applied to a polarizing plate stretched using a tenter so that the stretching axis is at an angle of 45 ° with respect to the absorption axis. The same good results as described above were obtained.

(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 5-1 according to the present invention was used. The bend alignment liquid crystal cell described in Example 9 of JP-A-2002-62431 was attached 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.

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

[Example 6]
Cellulose ester film A obtained by peeling off the releasable protective film from the cellulose ester film laminate 2-1 of the present invention produced in Example 2 was prepared as Cellulose ester film A in Example 13 of JP-A-2002-265636. It was used instead of the triacetate film sample 1301. Then, a bend-aligned 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]
Cellulose triacetate in Example 14 of Japanese Patent Application Laid-Open No. 2002-265636 was obtained by separating the cellulose ester film A obtained by peeling the release protective film from the cellulose ester film laminate 1-1 of the present invention produced in Example 1. Used in place of the film sample 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]
(1) Saponification of cellulose ester film laminate with protective film The cellulose ester film laminate 1-1 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. And it apply | coated at 10 g / m < ² > on the cellulose-ester film of 60 degreeC, 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 1-1).

(2) Production of Polarizing Plate Consisting of Cellulose Ester Film Laminate with Protective Film According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a peripheral speed difference is given between two pairs of nip rolls, and the film is stretched in the longitudinal direction and has a thickness of 20 μm. A polarizing film (polarizing film sample 8-2) was prepared. The degree of polarization was 99.99%.

(3) Preparation of retardation film 5% by mass of N, N ′, N ″ -tri-m-toluyl-1,3,5-triazine-2,4,6-triamine is added to the cellulose ester to obtain a solution flow. The cellulose triacetate (Re 60 nm, Rth 200 nm, film thickness 80 μm) obtained by stretching and stretching 1.32 times in the width direction while drying in the presence of residual solvent was saponified according to the following: KOH. Was dissolved to 1.5 mol / L and then adjusted to 60 ° C. and used as a saponification solution, and applied to a cellulose triacetate film at 60 ° C. at 10 g / m ² and saponified for 1 minute. . Thereafter, 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, dry in 5 minutes It was. The sample was a cellulose triacetate film sample 8-3.

(4) Production of retardation plate A saponified cellulose ester film laminate 1-1 with a peelable protective film according to the present invention, and a cellulose triacetate sample 8-3 for retardation, using a polarizing film sample 8-2, Laminate 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 A phase difference plate was produced by sandwiching with a layer configuration of 8-3. At this time, the polarizing axis and the slow axis direction of the cellulose ester film A were laminated so as to be 90 ° to obtain a retardation plate sample 8-4 having the cellulose ester film laminate of the present invention.

(5) Evaluation The peelable 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. No bright spot foreign matter was observed. From this, it was proved that the cellulose ester film laminate in which the peelable protective film according to the present invention was laminated was excellent in handling at the time of producing the retardation plate.

[Comparative Example 4]
In Example 8 (1), the cellulose ester film laminate 1-1 of the present invention prepared in (5) of Example 1 was used as the cellulose ester film A according to the present invention prepared in (1) of Example 1. A comparative retardation plate sample 8-5 was obtained in the same manner as in Example 8 except that the change was made. 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 of 0.5 mm or more were observed / m ² . Therefore, as compared with the case where the peelable protective film according to the present invention of Example 8 was applied, the comparative retardation plate sample 8-5 without the peelable protective film was not contaminated by handling during the production of the retardation plate. It included problems due to the occurrence. From the above, it was demonstrated that the cellulose ester film laminate of the present invention is excellent.

[Example 9]
(1) Preparation of saponification-treated film On one side (air surface side) of cellulose ester film A obtained in (3) of Example 1, an alkaline saponification aqueous solution (S-1) having the following formulation kept at 40 ° C. was rodd 20 ml / m ^{2 was} applied with a coater. After being kept under a steam far infrared heater (manufactured by Noritake Co., Ltd.) heated to 110 ° C. for 7 seconds to bring the surface temperature of the film to 40 ° C. to 50 ° C. 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 solution (S-1) Formulation KOH 560 parts by weight _{C 14 H 29 -O- (CH 2} CH 2 O) ( manufactured by Nissin Chemical Industry (Ltd.)) -H 100 parts by weight defoamer Surfynol DF110D 2 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 Was 180 mS / cm. 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.

(2) Adhesion and evaluation of peelable protective film The peelable protective film A was laminated to the saponified surface of the obtained saponified film sample 1-1-K1 in the same manner as in (4) of Example 1 to obtain a cellulose ester. A film laminate sample K1-A was prepared. The average thickness of the obtained cellulose ester film laminate sample K1-A was 104 μm. Moreover, when the thickness dispersion | variation in the width direction and longitudinal direction of a laminated body was measured, they were 2.7 micrometers and 1.1 micrometers, respectively.
The same evaluation as (6) of Example 1 was performed on the cellulose ester film laminate sample K1-A. As a result, it was confirmed that the cellulose ester film 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 cellulose-ester film laminated body sample K1-A, all obtained the same measurement result and evaluation result as (6) of Example 1. FIG.

[Comparative Example 5]
A comparative sample 5 was produced in the same manner as in Example 9 except that the peelable protective film A was not attached in Example 9. The film in which the cellulose ester film of the comparative sample 5 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 5 was sandwiched between two orthogonal polarizing films, and light leakage observed visually was observed. As a result, 15 mm / m or more of light leakage of 0.5 mm or more was observed. It was the level which becomes a problem as a state. Therefore, it became clear that the peelable protective film of the present invention has an excellent foreign matter exclusion effect.

[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 the film formation of Example 1 (3), the same touch roll as the first example of WO 97/28950 pamphlet (which is described as a sheet forming roll) is used (however, in the metal outer cylinder) The cooling water used was changed from oil having a temperature of 18 ° C. to 120 ° C.), touch roll linear pressure 15 kg / cm, and touch roll temperature 115 ° C. When the number of fine irregularities was measured, the cellulose ester film of Example 1 was 3, whereas in Example 11 using the touch roll, there were 0, and the touch roll film forming method was further improved. It was confirmed to be excellent.

[Example 12]
Evaluation was conducted in the same manner as in Example 1 except that cellulose ester E having a substitution degree of propionyl group of 1.5, a substitution degree of acetyl group 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 A. In all cases, good results were obtained.

[Example 13]
Evaluation was performed in the same manner as in Example 8 except that cellulose ester film F having a substitution degree of propionyl group of 0.7, an substitution degree of acetyl group of 1.8 and a weight average molecular weight of 160000 was used instead of cellulose acylate A. Both obtained good results.

[Example 14]
The same procedure as in Example 8 except that cellulose ester F having a propionyl group substitution degree of 0.7, an acetyl group substitution degree of 1.8, and a weight average molecular weight of 160000 was used instead of cellulose acylate A, and no plasticizer was added. As a result, all of them obtained good results.

  The cellulose ester film laminate of the present invention can easily supply a cellulose ester film having a small surface charge, good surface shape and no scratches by peeling the peelable protective film having a conductive adhesive layer. 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. The peelable protective film of the present invention can not only keep the charge of itself low, but also produce optical parts such as polarizing plates, optical compensation films, and antireflection films by laminating cellulose ester films on other films. In this case, the charging can be kept low. For this reason, 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, a foreign matter failure on a display screen, and a change in visibility over time can be suppressed. The liquid crystal display device can be easily manufactured with a high yield. 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 formation by a touch roll method.

Explanation of symbols

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

Claims (22)

At least one surface of the cellulose ester film satisfying the following formulas (S-1) to (S-3) has a conductivity of 10 ¹² Ω or less in an environment of at least one kind of resin base material and 25 ° C. and a relative humidity of 40%. A cellulose ester film laminate in which a releasable protective film comprising at least one pressure-sensitive adhesive layer is laminated.
Formula (S-1) 2.0 <= A + B <= 3.0
Formula (S-2) 0 ≦ A ≦ 2.5
Formula (S-3) 0.5 ≦ 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 cellulose ester film satisfying the formulas (S-1) to (S-3) is melt-formed.   The cellulose ester film laminate according to claim 1, wherein the cellulose ester film satisfying the formulas (S-1) to (S-3) has a residual solvent amount of 0.01% by mass or less. The cellulose ester film laminate according to any one of claims 1 to 3, wherein the adhesive layer has a conductivity of 10 ¹² Ω or less in an environment of 25 ° C and a relative humidity of 10%.   5. The release voltage is −1 kV to +1 kV in an environment of 25 ° C. and a relative humidity of 60% when the releasable protective film is peeled from the cellulose ester film. The cellulose ester film laminate according to Item.   The pressure-sensitive adhesive layer of the releasable protective film is composed of a pressure-sensitive adhesive containing a quaternary substituted ammonium salt or pyridium salt, an acrylic polymer having a hydroxyl group, and a polyisocyanate. The cellulose-ester film laminated body as described in any one.   The cellulose ester film laminate according to any one of claims 1 to 6, wherein the surface roughness of the surface opposite to the pressure-sensitive adhesive layer of the releasable protective film is 0.002 µm or more.   The resin substrate of the releasable protective film contains at least one selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polycarbonate, polyimide, polystyrene, polyacrylonitrile, and polymethacrylate. The cellulose-ester film laminated body as described in any one of Claims 1-7 to do.   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. Cellulose ester film laminate as described in 1.   The weight average molecular weight (Mw) of the cellulose ester is 50,000 to 350,000, and the weight average molecular weight / number average molecular weight (Mw / Mn) is 1.5 to 6.0. The cellulose ester film laminate according to any one of 9.   The cellulose ester film according to any one of claims 1 to 10, 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. Laminated body.   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. The cellulose ester film laminate according to Item. It is a manufacturing method of the cellulose-ester film laminated body as described in any one of Claims 1-12,
A step of producing a cellulose ester film by melt film formation;
The cellulose ester film is the adhesive material layer side of a releasable protective film comprising at least one resin substrate and at least one adhesive layer having a conductivity of 10 ¹² Ω or less in an environment of 25 ° C. and relative humidity of 40%. And a step of laminating the cellulose ester film laminate.   The method for producing a cellulose ester film laminate according to claim 13, wherein the melt formation of the cellulose ester film is performed at a melting temperature of 180 to 240 ° C.   The method for producing a cellulose ester film laminate according to claim 13 or 14, wherein the melt film formation is performed using a touch roll.   The method for producing a cellulose ester film laminate according to any one of claims 13 to 15, further comprising a step of saponifying at least one surface of the cellulose ester film.   In the pressure-sensitive adhesive layer that appears by peeling off the release sheet from the release sheet with the release sheet prepared from the release sheet with release sheet prepared by laminating the release sheet on the adhesive layer of the release protection film The said cellulose-ester film is laminated | stacked, The manufacturing method of the cellulose-ester film laminated body as described in any one of Claims 13-16 characterized by the above-mentioned.   The cellulose ester film lamination according to any one of claims 13 to 17, wherein the step of laminating the releasable protective film and the cellulose ester film is performed in air cleaned to class 10000 or less. Body manufacturing method.   A polarizing plate using a polarizing film and a cellulose ester film obtained by peeling off the releasable protective film from the cellulose ester film laminate according to any one of claims 1 to 12. .   An optical compensation film using a cellulose ester film obtained by peeling off the releasable protective film from the cellulose ester film laminate according to any one of claims 1 to 12.   An antireflection film using a cellulose ester film obtained by peeling off the releasable protective film from the cellulose ester film laminate according to any one of claims 1 to 12.   A liquid crystal display using at least one selected from the group consisting of the polarizing plate according to claim 19, the optical compensation film according to claim 20, and the antireflection film according to claim 21. apparatus.

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