KR20090113347A - Method of manufacturing transparent polymer film and transparent polymer film manufactured by the same, phase difference film, polarizing plate, and liquid display device - Google Patents

Abstract

The manifestation of retardation of transparent polymer film can be easily regulated by heat treatment of the polymer film at temperature T (unit, °C) satisfying the requirement of the formula: Tc<=T<Tm0 (1) wherein Tc is the crystallization temperature (unit, °C) of polymer film before heat treatment and Tm0 the melting point (unit, °C) of polymer film before heat treatment.

Description

The manufacturing method of a transparent polymer film, and the transparent polymer film, retardation film, polarizing plate, and liquid crystal display device which are manufactured by this method, PHASE DIFFERENCE FILM, POLARIZING PLATE, AND LIQUID DISPLAY DEVICE}

The present invention relates to a method for producing a transparent polymer film. More specifically, it is related with the manufacturing method of the transparent polymer film which can control retardation. Moreover, this invention relates also to the transparent polymer film manufactured by this manufacturing method, retardation film, polarizing plate, and liquid crystal display device using the same.

The polymer film represented by a cellulose ester, polyester, a polycarbonate, a cycloolefin polymer vinyl polymer, and polyimide etc. is used for a silver halide photosensitive material, a retardation film, a polarizing plate, and an image display apparatus. From these polymers, since the film which is more excellent in planarity and uniformity can be manufactured, it is employ | adopted widely as a film for optical use. For example, the cellulose-ester film which has an appropriate water vapor transmission rate can be directly attached online with the polarizing film which consists of the most common polyvinyl alcohol (PVA) / iodine. For this reason, cellulose acylate, especially cellulose acetate, is widely used as a protective film of a polarizing plate.

On the other hand, when using a transparent polymer film for optical uses, such as a retardation film, the support body of retardation film, the protective film of a polarizing plate, and a liquid crystal display device, the control of the optical anisotropy is the performance of a display device (for example, visibility It is a very important factor in determining). Recently, in accordance with the demand for wide viewing angle of a liquid crystal display device, an improvement in retardation compensation has been required, and the retardation value (Re; And the retardation value (Rth; sometimes simply referred to as "Rth" hereafter) in the film thickness direction are required. Especially, since the transparent polymer film which satisfy | fills | Rth | / Re <0.5 is not easy to manufacture, it is calculated | required to develop the manufacturing method easily.

On the other hand, as a manufacturing method of a polymer film, the continuous manufacturing method which adhere | attaches a heat shrinkable film to a polymer film, heat-stretches, and peels a heat shrinkable film after that is disclosed (for example, patent document 1, See Patent Document 2). According to the examples of these documents, it was found that the polycarbonate film or the like produced by this method satisfies the condition of | Rth | / Re <0.5. However, this method consumes a large amount of heat-shrinkable film, and there is a problem that there is a variation in the quality of the obtained film. This problem was particularly noticeable in high modulus polymers such as cellulose esters.

Patent Document 1: Japanese Patent Application Laid-Open No. 5-157911

Patent Document 2: Japanese Patent Application Laid-Open No. 2000-231016

Disclosure of Invention

Problems to be Solved by the Invention

As described above, no practical method for adjusting Re and Rth within a desired range has been found in the related art by a simple method. In view of such a problem of the prior art, the present inventors set as an object to provide a method for producing a transparent polymer film that can adjust the expression of retardation by a relatively easy operation.

Means to solve the problem

Found out that the present inventors have intensively studied the results of extensive, typically, it does not occur in the drying step, to solve the problems of the prior art by heating the polymer film at a temperature of less than Tc Tm _0. That is, the following invention was provided as a means to solve the subject.

[1] A method for producing a transparent polymer film, comprising the step of heat-treating the polymer film at a temperature T (unit; ° C.) that satisfies the conditions of the following formula (1).

Equation (1): Tc≤T <Tm ₀

[Wherein Tc represents the crystallization temperature (unit; ° C.) of the polymer film before the heat treatment, and Tm ₀ represents the melting point (unit; ° C.) of the polymer film before the heat treatment.]

[2] The method for producing a transparent polymer film according to [1], wherein the film is stretched simultaneously with the heat treatment.

[3] The method for producing a transparent polymer film according to [1] or [2], which is carried out while conveying the heat treatment.

[4] The method for producing a transparent polymer film according to [1], which is carried out while conveying the heat treatment and stretching in the conveying direction.

[5] The method for producing a transparent polymer film according to any one of [1] to [4], wherein the film is stretched at a temperature of less than Tc after the heat treatment.

[6] The method for producing a transparent polymer film according to [5], which is carried out while conveying the heat treatment and is stretched in a direction orthogonal to the conveyance direction during the heat treatment at a temperature less than Tc after the heat treatment.

[7] The method for producing a transparent polymer film according to any one of [1] to [6], wherein the polymer film before the heat treatment is stretched before the heat treatment.

[8] The method for producing a transparent polymer film according to [7], wherein the heat treatment is performed while stretching in the same direction as the stretching before the heat treatment.

[9] The method for producing a transparent polymer film according to any one of [1] to [8], wherein the polymer film is shrunk by 5 to 80% during the heat treatment.

[10] The method for producing a transparent polymer film according to [9], wherein the polymer film before the heat treatment is conveyed and manufactured, and the shrinkage during the heat treatment is performed in a direction orthogonal to the conveying direction.

[11] The method for producing a transparent polymer film according to any one of [1] to [10], wherein the film is cooled at 100 to 1,000,000 ° C / min after the heat treatment.

[12] The method for producing a transparent polymer film according to any one of [1] to [11], wherein the polymer is cellulose acylate.

[13] The method for producing a transparent polymer film according to [12], wherein the cellulose acylate satisfies the following formula (3).

Equation (3): 2.70 <SA + SB≤3.00

[In formula, SA shows the substitution degree of the acetyl group substituted by the hydroxyl group of a cellulose, and SB shows the substitution degree of the C3 or more acyl group substituted by the hydroxyl group of a cellulose. "

[14] The method for producing a transparent polymer film according to [12] or [13], wherein the cellulose acylate satisfies the following formula (4).

Equation (4): 0 <SB≤3.0

[In formula, SB shows the substitution degree of the C3 or more acyl group substituted by the hydroxyl group of a cellulose.]

[15] [1] to [14], wherein the polymer film before the heat treatment is conveyed and manufactured, and is stretched in the conveying direction by 0.1% or more and less than 15% in the state of 5 to 1000% of residual solvent. The manufacturing method of the transparent polymer film in any one of Claims.

[16] The polymer film before the heat treatment is conveyed and manufactured, and in this conveying direction, 15 to 300% is stretched in a state where the residual solvent amount is 5 to 1000%. The manufacturing method of the transparent polymer film of any one of Claims.

[17] The method for producing a transparent polymer film according to any one of [1] to [16], wherein the water vapor transmission rate in terms of 80 µm of the polymer film before the heat treatment is 100 g / (m 2 · day) or more.

[18] The method for producing a transparent polymer film according to any one of [1] to [17], wherein the polymer film before the heat treatment contains an additive composition for raising the Rth of the polymer film before the heat treatment.

[19] A method for producing a transparent polymer film according to any one of [1] to [18], wherein a transparent polymer film that satisfies the following formula (2) is produced.

Equation (2): Rth / Re <0.5

[Wherein Re represents a retardation value (unit; nm) in the in-plane direction, and Rth represents a retardation value (unit; nm) in the film thickness direction.]

[20] A method for adjusting the expression of retardation of a transparent polymer film, wherein the transparent polymer film is heat treated at a temperature T (unit; ° C.) that satisfies the conditions of the following formula (1).

Equation (1): Tc≤T <Tm ₀

[Wherein Tc represents the crystallization temperature (unit; ° C.) of the polymer film before the heat treatment, and Tm ₀ represents the melting point (unit; ° C.) of the polymer film before the heat treatment.]

[21] A method for producing a transparent polymer film satisfying the following formula (2), comprising the step of heat-treating the transparent polymer film at a temperature T (unit; ° C.) satisfying the conditions of the following formula (1). .

Equation (1): Tc≤T <Tm ₀

[Wherein Tc represents the crystallization temperature (unit; ° C.) of the polymer film before the heat treatment, and Tm ₀ represents the melting point (unit; ° C.) of the polymer film before the heat treatment.]

Equation (2): Rth / Re <0.5

[Wherein Re represents a retardation value (unit; nm) in the in-plane direction, and Rth represents a retardation value (unit; nm) in the film thickness direction.]

[22] A transparent polymer film produced by the production method according to any one of [1] to [21].

[23] The transparent polymer film according to [22], wherein the polymer is cellulose acylate.

[24] A retardation film having at least one transparent polymer film as described in [22] or [23].

[25] A polarizing plate having at least one transparent polymer film as described in [22] or [23].

[26] The polarizing plate according to [25], wherein the transparent polymer film is directly attached to the polarizing film.

[27] A liquid crystal display device comprising the transparent polymer film as described in [22] or [23], the retardation film as described in [24], or the polarizing plate as described in [25] or [26].

Effects of the Invention

According to the manufacturing method of this invention, the expression property of the retardation of a transparent film can be adjusted by performing a comparatively simple operation called heat processing. For example, the transparent film of the retardation area | region, such as | Rth | Re / 0.5 which was difficult to achieve conventionally, can also be manufactured easily.

Implement the invention  Best form for

Hereinafter, the manufacturing method of the transparent polymer film of this invention, and the transparent polymer film manufactured by this method are demonstrated in detail. Although description of the element | module described below is based on typical embodiment of this invention, this invention is not limited to such embodiment. In addition, the numerical range displayed using "-" in this specification means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

<< manufacturing method of transparent polymer film >>

[Polymer]

First, the polymer which can be used for the manufacturing method of the transparent polymer film of this invention is demonstrated.

As a polymer which becomes a component of the transparent polymer film of this invention, a cellulose ester (for example, a cellulose triacetate, a cellulose acetate propionate, a cellulose acetate butyrate, a cellulose tripropionate, a cellulose diacetate), a polyolefin ( For example, polyethylene, polypropylene, norbornene-based polymer), polyester (e.g., polymethacrylic acid ester, polyacrylic acid ester), polycarbonate, cycloolefin polymer, polyarylate, polysulfone, vinyl polymer ( For example, the polymer which can comprise the transparent polymer film which can be used for optical uses, such as a polyvinyl alcohol), a polyamide, a polyimide, a cycloolefin copolymer, a polynorbornene, etc. is mentioned. The polymer preferably has a hydrophilic structure such as hydroxyl groups, amides, imides or esters in the main chain or side chain in order to achieve appropriate moisture permeability. In this invention, a copolymer may be used and a polymer mixture may be used. As said polymer, a cellulose ester is preferable and especially a cellulose acylate is more preferable.

The polymer may be a powder or particulate, or may be pelletized.

It is preferable that the water content of the said polymer is 1.0 mass% or less, It is more preferable that it is 0.7 mass% or less, It is most preferable that it is 0.5 mass% or less. Moreover, it is preferable that the said water content is 0.2 mass% or less in some cases. When the moisture content of the said polymer is not in a preferable range, it is preferable to use, after drying the said polymer by dry wind, heating, etc.

These polymers may be used independently and may use two or more types of polymers together.

As said cellulose ester, the compound which has the cellulose ester compound and the ester substituted cellulose frame | skeleton obtained by introduce | transducing a functional group biologically or chemically from a cellulose as a raw material is mentioned, Especially, a cellulose acylate is especially preferable.

Moreover, it is preferable to use the cellulose acylate mentioned above as a polymer as a main component of the transparent polymer film of this invention. Here, "polymer as a main component" shows the polymer when it consists of a single polymer, and when it consists of several polymers, it shows the polymer with the highest mass fraction among the polymer which comprises.

The cellulose ester is an ester of cellulose and an acid. As the acid constituting the ester, an organic acid is preferable, carboxylic acid is more preferable, a fatty acid having 2 to 22 carbon atoms is more preferable, and a lower fatty acid having 2 to 4 carbon atoms is most preferable.

The cellulose acylate is an ester of cellulose and carboxylic acid. In the said cellulose acylate, all or part of the hydrogen atom of the hydroxyl group which exists in the 2nd, 3rd, and 6th positions of the glucose unit which comprises a cellulose is substituted by the acyl group. Examples of the acyl group include, for example, an acetyl group, propionyl group, butyryl group, isobutyryl group, pivaloyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group And tetradecanoyl group, hexadecanoyl group, octadecanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group and cinnamoyl group. As the acyl group, acetyl group, propionyl group, butyryl group, dodecanoyl group, octadecanoyl group, pivaloyl group, oleoyl group, benzoyl group, naphthylcarbonyl group and cinnamoyl group are preferable, and acetyl group and propionyl Group, butyryl group is most preferred.

The cellulose ester may be an ester of cellulose and a plurality of acids. In addition, the cellulose acylate may be substituted with a plurality of acyl groups.

When substitution degree of the acetyl group (C2 number) substituted by the hydroxyl group of the cellulose of cellulose acylate is SA, SA and SB are represented when SB is the substitution degree of the C3 or more acyl group substituted by the hydroxyl group of cellulose. By adjusting, the expression of Re of the transparent polymer film manufactured by the manufacturing method of this invention, and the humidity dependence of retardation can be adjusted. Moreover, Tc can also be adjusted and thereby the heat processing temperature can be adjusted. In addition, the humidity dependence of retardation is a change of retardation by humidity.

SA + SB is appropriately adjusted according to the optical properties required for the transparent polymer film produced by the production method of the present invention, which is the film of the present invention, preferably 2.70 <SA + SB≤3.00, more preferably 2.88 ≤ SA + SB ≤ 3.00, more preferably 2.89 ≤ SA + SB ≤ 2.99, still more preferably 2.90 ≤ SA + SB ≤ 2.98, particularly preferably 2.92 ≤ SA + SB ≤ 2.97. By increasing SA + SB, Re obtained after the heat treatment can be made larger, and Tc can be made lower, and the humidity dependence of the retardation can also be improved. By setting Tc low, it becomes possible to set heat processing temperature comparatively low.

Moreover, the humidity dependence of the retardation of the transparent polymer film manufactured by the manufacturing method of this invention can be adjusted by adjusting SB. By making SB large, the humidity dependence of retardation can be reduced, and melting | fusing point falls. In consideration of the balance between the humidity dependence of the retardation and the lowering of the melting point, the range of SB is preferably 0 <SB≤3.0, more preferably 0 <SB≤1.0, still more preferably 0.1≤SB≤0.7. In addition, when all the hydroxyl groups of a cellulose are substituted, said substitution degree is three.

A cellulose ester can be synthesize | combined by a well-known method.

For example, the basic principle of the method for synthesizing cellulose acylate is described in Mikata Nobuhiko et al., Pages 180-190 of wood chemistry (Kyoritsu Publication, 1968). As a typical synthesis | combining method of a cellulose acylate, the liquid acylation method by a carboxylic anhydride-carboxylic acid-sulfuric acid catalyst is mentioned. Specifically, first, a cellulose raw material such as cotton linter or wood pulp is pretreated with an appropriate amount of carboxylic acid such as acetic acid, and then introduced into a pre-cooled acylation mixture to be esterified to completely cellulose acylate (2-position, The sum of the acyl substitution degree of the 3rd and 6th positions synthesizes approximately 3.00). The acylated mixed solution generally contains carboxylic acid as a solvent, carboxylic anhydride as an esterifying agent and sulfuric acid as a catalyst. Moreover, it is common to use the said carboxylic anhydride in excess amount stoichiometrically rather than the sum total of the cellulose which reacts with this, and the moisture which exists in the system.

Then, after completion of the acylation reaction, water or hydrous acetic acid is added to perform hydrolysis of the excess carboxylic anhydride remaining in the system. In addition, in order to partially neutralize the esterification catalyst, an aqueous solution containing a neutralizing agent (for example, a carbonate, acetate, hydroxide or oxide of calcium, magnesium, iron, aluminum or zinc) may be added. Further, the obtained complete cellulose acylate is saponified by maintaining at a temperature of 20 to 90 ° C in the presence of a small amount of acylation reaction catalyst (generally, sulfuric acid remaining) to change to cellulose acylate having a desired acyl substitution degree and polymerization degree. Let's do it. When the desired cellulose acylate is obtained, the catalyst remaining in the system is completely neutralized using the neutralizing agent or the like, or the cellulose acylate solution is introduced into water or dilute acetic acid without neutralizing the catalyst (or cellulose In the acylate solution, water or dilute acetic acid is added) to separate the cellulose acylate, and the cellulose acylate as a target can be obtained by washing and stabilizing treatment.

150-500 are preferable, as for the polymerization degree of the said cellulose acylate, 200-400 are more preferable, and 220-350 are still more preferable. The said viscosity average polymerization degree can be measured in accordance with description of the intrinsic viscosity method (Uta Kazuo, Saito Hideo, Textile Society, Vol. 18 No. 1, 105-120 pages, 1962), such as Uta. About the measuring method of the said viscosity average polymerization degree, Unexamined-Japanese-Patent No. 9-95538 also has description.

Moreover, although the cellulose acylate with few low molecular components has a high average molecular weight (polymerization degree), a viscosity becomes a value lower than normal cellulose acylate. The cellulose acylate with few such low molecular components can be obtained by removing a low molecular component from the cellulose acylate synthesize | combined by a normal method. Removal of the low molecular weight component can be performed by washing a cellulose acylate with a suitable organic solvent. Moreover, the cellulose acylate with few low molecular weight components can also be obtained by synthesis. When synthesize | combining the cellulose acylate with few low molecular components, it is preferable to adjust the amount of sulfuric acid catalysts in an acylation reaction with 0.5-25 mass parts with respect to 100 mass of cellulose. When the quantity of the said sulfuric acid catalyst is made into the said range, the cellulose acylate (uniform in molecular weight distribution) preferable also in the molecular weight distribution can be synthesize | combined. The polymerization degree and molecular weight distribution of cellulose acylate can be measured by gel permeation chromatography (GPC) or the like.

About the raw material surface of a cellulose ester, and the synthesis | combining method, it mentions also in pages 7-12 of the invention association publication publication (Publication Publication No. 2001-1745, issued March 15, 2001, Invention Association).

[Polymer solution]

The polymer film (hereinafter, also referred to as "polymer film before heat treatment" in the specification) used in the production method of the present invention can be produced by a solution casting film forming method, for example, from a polymer solution containing the polymer or various additives. Can be. Below, the polymer solution which can be used for the solution casting film forming method is demonstrated.

(menstruum)

As a main solvent of the polymer solution (preferably a cellulose ester solution) used for manufacture of the polymer film used for the manufacturing method of this invention, the organic solvent which is a good solvent of this polymer can be used preferably. As such an organic solvent, the organic solvent whose boiling point is 80 degrees C or less is more preferable from a viewpoint of reducing a dry load. It is more preferable that it is 10-80 degreeC, and, as for the boiling point of the said organic solvent, it is especially preferable that it is 20-60 degreeC. Moreover, the organic solvent whose boiling point is 30-45 degreeC can also be used suitably as said main solvent in some cases.

Such main solvents include halogenated hydrocarbons, esters, ketones, ethers, alcohols and hydrocarbons, and these may have a branched structure or a cyclic structure. Moreover, the said main solvent may have two or more of functional groups (that is, -O-, -CO-, -COO-, -OH) of ester, ketone, ether, and alcohol. In addition, the hydrogen atom in the hydrocarbon part of the said ester, ketone, ether, and alcohol may be substituted by the halogen atom (especially a fluorine atom). In addition, when the main solvent of the polymer solution (preferably cellulose ester solution) used for manufacture of the polymer film used for the manufacturing method of this invention consists of a single solvent, it represents the solvent and consists of several solvent. In the case, the solvent with the highest mass fraction is shown among the solvent which comprises. As a main solvent, a halogenated hydrocarbon is mentioned preferably.

As said halogenated hydrocarbon, chlorinated hydrocarbon is more preferable, For example, dichloromethane, chloroform, etc. are mentioned, Dichloromethane is more preferable.

As said ester, methyl formate, ethyl formate, methyl acetate, ethyl acetate, etc. are mentioned, for example.

As said ketone, acetone, methyl ethyl ketone, etc. are mentioned, for example.

As said ether, for example, diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dimethoxymethane, 1,3-dioxolane, 4-methyldioxolane, tetrahydrofuran, methyltetra Hydrofuran, 1, 4- dioxane, etc. are mentioned.

As said alcohol, methanol, ethanol, 2-propanol, etc. are mentioned, for example.

As said hydrocarbon, n-pentane, cyclohexane, n-hexane, benzene, toluene etc. are mentioned, for example.

Examples of the organic solvent used in combination with these main solvents include halogenated hydrocarbons, esters, ketones, ethers, alcohols and hydrocarbons, and these may have a branched structure or a cyclic structure. Moreover, as said organic solvent, you may have any two or more of functional groups (namely, -O-, -CO-, -COO-, -OH) of ester, ketone, ether, and alcohol. In addition, the hydrogen atom in the hydrocarbon part of the said ester, ketone, ether, and alcohol may be substituted by the halogen atom (especially a fluorine atom).

As said halogenated hydrocarbon, chlorinated hydrocarbon is more preferable, For example, dichloromethane, chloroform, etc. are mentioned, Dichloromethane is more preferable.

As said ester, methyl formate, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, pentyl acetate, etc. are mentioned, for example.

As said ketone, acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, etc. are mentioned, for example.

As said ether, for example, diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, 4- Methyldioxolane, tetrahydrofuran, methyltetrahydrofuran, anisole, a phentol, etc. are mentioned.

Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol, cyclohexanol, 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol, etc. are mentioned. Preferably they are C1-C4 alcohol, More preferably, they are methanol, ethanol or butanol, Most preferably, they are methanol and butanol.

As said hydrocarbon, n-pentane, cyclohexane, n-hexane, benzene, toluene, xylene etc. are mentioned, for example.

As an organic solvent which has the said 2 or more types of functional group, 2-ethoxy ethyl acetate, 2-methoxy ethanol, 2-butoxy ethanol, methyl aceto acetate, etc. are mentioned, for example.

When the polymer constituting the transparent polymer film of the present invention contains a hydrogen bonding functional group such as a hydroxyl group, an ester or a ketone, it is 5 to 30% by mass in the total solvent, more preferably 7 to 25% by mass, even more preferably It is preferable to contain 10-20 mass% alcohol from a viewpoint of reducing peeling load from a flexible support body. The polymer containing a hydrogen bondable functional group contains cellulose acylate.

By adjusting the alcohol content, the expression of Re or Rth of the transparent polymer film produced by the production method of the present invention can be easily adjusted. Specifically, by increasing the alcohol content, the heat treatment temperature can be set relatively low, or the reach range of Re or Rth can be made larger.

Moreover, the said polymer solution used for manufacture of the polymer film used for the manufacturing method of this invention has a small volatilization ratio with a halogenated hydrocarbon in the initial stage of a drying process, and the boiling point which concentrates gradually is 95 degreeC or more, and a cellulose It is preferable to contain 1-15 mass% of organic solvent which is a poor solvent of ester, More preferably, it is 1.5-13 mass%, More preferably, it is 2-10 mass%.

Although the example of the combination of the organic solvent used preferably as a solvent of the polymer solution used for manufacture of the polymer film used for the manufacturing method of this invention is given to the following, this invention is not limited to these. In addition, the numerical value of a ratio means a mass part.

(1) dichloromethane / methanol / ethanol / butanol = 80/10/5/5

(2) dichloromethane / methanol / ethanol / butanol = 80/5/5/10

(3) dichloromethane / isobutyl alcohol = 90/10

(4) dichloromethane / acetone / methanol / propanol = 80/5/5/10

(5) dichloromethane / methanol / butanol / cyclohexane = 80/8/10/2

(6) dichloromethane / methylethylketone / methanol / butanol = 80/10/5/5

(7) dichloromethane / butanol = 90/10

(8) dichloromethane / acetone / methylethylketone / ethanol / butanol = 68/10/10/7/5

(9) dichloromethane / cyclopentanone / methanol / pentanol = 80/2/15/3

(10) dichloromethane / methyl acetate / ethanol / butanol = 70/12/15/3

(11) dichloromethane / methylethylketone / methanol / butanol = 80/5/5/10

(12) dichloromethane / methylethylketone / acetone / methanol / pentanol = 50/20/15/5/10

(13) dichloromethane / 1,3-dioxolane / methanol / butanol = 70/15/5/10

(14) dichloromethane / dioxane / acetone / methanol / butanol = 75/5/10/5/5

(15) dichloromethane / acetone / cyclopentanone / ethanol / isobutyl alcohol / cyclohexane = 60/18/3/10/7/2

(16) dichloromethane / methylethylketone / acetone / isobutyl alcohol = 70/10/10/10

(17) dichloromethane / acetone / ethyl acetate / butanol / hexane = 69/10/10/10/1

(18) dichloromethane / methyl acetate / methanol / isobutyl alcohol = 65/15/10/10

(19) dichloromethane / cyclopentanone / ethanol / butanol = 85/7/3/5

(20) dichloromethane / methanol / butanol = 83/15/2

(21) dichloromethane = 100

(22) Acetone / ethanol / butanol = 80/15/5

(23) Methyl acetate / acetone / methanol / butanol = 75/10/10/5

(24) 1,3-dioxolane = 100

(25) dichloromethane / methanol = 85/15

(26) dichloromethane / methanol = 92/8

(27) dichloromethane / methanol = 90/10

(28) dichloromethane / methanol = 87/13

(29) dichloromethane / ethanol = 90/10

In addition, the detailed description in the case of using a non-halogen type organic solvent as a main solvent is disclosed in the invention association publication publication (Publication Publication No. 2001-1745, issued March 15, 2001, Invention Association), and can be used suitably. have.

(Solution concentration)

5-40 mass% is preferable, as for the polymer concentration in the said polymer solution to prepare, 10-30 mass% is more preferable, and 15-30 mass% is the most preferable.

The polymer concentration may be adjusted to a predetermined concentration in dissolving the polymer in a solvent. Moreover, after preparing the solution of low concentration (for example, 4-14 mass%) beforehand, you may evaporate a solvent and it may concentrate. Moreover, after preparing a high concentration solution previously, you may dilute. Moreover, the density | concentration of a polymer can also be reduced by adding an additive.

(additive)

The said polymer solution used for manufacture of the polymer film used for the manufacturing method of this invention can contain the additive of various liquid or solid according to a use in each preparation process. Examples of the additive include plasticizers (preferable addition amount is 0.01 to 10% by mass relative to the polymer, the same as below), ultraviolet absorber (0.001 to 1% by mass), and fine powder (0.001 to 1 mass) having an average particle size of 5 to 3000 nm. %), Fluorine-based surfactant (0.001 to 1% by mass), release agent (0.0001 to 1% by mass), deterioration inhibitor (0.0001 to 1% by mass), optically anisotropic control agent (0.01 to 10% by mass), infrared absorber (0.001 to 1%) 1 mass%) is included.

The said plasticizer and the said optically anisotropic control agent are organic compounds with a molecular weight of 3000 or less, Preferably it is a compound provided with both a hydrophobic part and a hydrophilic part. These compounds change the retardation value by orienting between polymer chains. Moreover, by using these compounds together with the cellulose acylate used especially preferably in this invention, hydrophobicity of a film can be improved and the humidity change of retardation can be reduced. Moreover, the wavelength dependence of retardation can also be controlled effectively by using together the said ultraviolet absorber and the said infrared absorber. It is preferable that all the additives used for the transparent polymer film of this invention are substantially free of volatilization in a drying process.

Among the plasticizers and the optically anisotropic control agent, in the present invention, a plasticizer or an optically anisotropic control agent having an effect of raising the Rth of the polymer film before the heat treatment can be preferably used in accordance with the desired Re and Rth values. As for these Rth rise, 8-100 nm is more preferable, 10-50 nm is still more preferable, 15-30 nm is the most preferable. By adding such an additive, it is possible to selectively increase the Rth of the film (disk) before carrying out the manufacturing method of the present invention. Therefore, by applying the manufacturing method of the present invention to such a disk, the Rth / Re value can be increased. For example, a film that satisfies Rth / Re ≧ -0.39, Re> 0, and Rth <0 at the same time can be produced.

Moreover, according to the Re and Rth value made into the objective, the plasticizer and optically anisotropic control agent which have the effect which does not change the Rth of the film before heat processing very much, or makes it fall can be used preferably. These Rth fluctuation ranges (Rth of the disk without Rth-additive of the additive) are more preferably -100 to less than 8 nm, still more preferably -50 to 5 nm, most preferably -30 to 5 nm. . By adding such additives, the mobility of the polymer molecules during heat treatment can be improved, and therefore, the expression of Re and Rth of the transparent polymer film produced by the production method of the present invention can be further adjusted. You can set it lower, or increase the reach of Re or Rth. Therefore, by combining optically anisotropic control agents such as a retardation increasing agent, not only a transparent polymer film satisfying Rth / Re <0.5 but also a transparent polymer film satisfying Rth / Re ≧ 0.5 can be appropriately produced. have.

In the present invention, the variation of Rth by the additive is measured by Rth (Rth ₁ ) and methanol measured after the film is immersed in methanol at 25 ° C., sonicated for 3 hours, and further dried at 80 ° C. for 10 minutes. It can evaluate by the difference (Rth _0- Rth ₁ ) of Rth (Rth ₀ ) before a process. In addition, in the case of the additive which is difficult to extract by methanol, Rth (Rth ₂ ) before the heat treatment of the film formed from the dope solution which added the additive, and Rth (Rth before the heat treatment of the film formed from the dope solution which did not add the additive). ₃₎ may be evaluated by a difference (Rth ₂ -Rth _3).

As such an additive, specifically, the compound which has one or more aromatic rings is preferable, It is more preferable to have 2-15 pieces, It is still more preferable to have 3-10 pieces. It is preferable that each atom other than the aromatic ring in a compound is arrangement | positioning near the same plane as an aromatic ring, and, when it has two or more aromatic rings, it is preferable that aromatic rings also arrange | position near to the same plane. Moreover, in order to raise Rth selectively, it is preferable that the presence state in the film of an additive exists in the direction parallel to a film plane.

The said additive may be used independently and may be used in combination of 2 or more types of additives.

As an additive which has the effect of raising Rth, specifically, the plasticizer as described on pages 33-34 of Unexamined-Japanese-Patent No. 2005-104148, and the optical anisotropy as described in pages 38-89 of Unexamined-Japanese-Patent No. 2005-104148 are mentioned. Control agent and the like.

From the viewpoint of reducing the humidity change of the retardation, the amount of these additives added is more preferable. However, with the increase of the amount of addition, the glass transition temperature (Tg) of the polymer film decreases and in the manufacturing process of the film. It becomes easy to cause the volatilization problem of an additive. Therefore, when using the cellulose acetate used more preferably by this invention as a polymer, 0.01-30 mass% is preferable with respect to the said polymer, and, as for the addition amount of the said additive of molecular weight 3000 or less, 2-30 mass% is more preferable. 5-20 mass% is more preferable.

The plasticizer and optically anisotropic control agent which can be used suitably when using cellulose acylate as a polymer in this invention are described in Unexamined-Japanese-Patent No. 2005-104148 and 2001-151901. Moreover, about an infrared absorber, it describes in Unexamined-Japanese-Patent No. 2001-194522. The time to add an additive can be suitably determined according to the kind of additive.

(Preparation of Polymer Solution)

Preparation of the polymer solution is, for example, Japanese Unexamined Patent Publications No. 58-127737, No. 61-106628, Japanese Unexamined Patent Publications No. Hei 2-276830, Hei 4-259511, Hei 5-163301, Hei 9-95544, Flat 10-45950, Flat 10-95854, Flat 11-71463, Flat 11-302388, Flat 11-322946, Flat 11-322947, Flat 11-323017, Japanese Unexamined Patent It can carry out according to the preparation method described in Unexamined-Japanese-Patent No. 2000-53784, 2000-273184, 2000-273239. Specifically, the polymer and the solvent are mixed and stirred to swell, optionally cooled and heated to dissolve, and then filtered to obtain a polymer solution.

In this invention, in order to improve the solubility to the solvent of a polymer, you may include the process of cooling and / or heating a mixture of a polymer and a solvent.

When a halogen-based organic solvent is used as the solvent and cellulose acylate is used as the polymer to cool the mixture of the polymer and the solvent, the mixture is preferably cooled to -100 to 10 ° C. Moreover, it is preferable to include the process of swelling at -10-39 degreeC in the process before a cooling process, and the process of heating to 0-39 degreeC in the process after cooling.

When heating the mixture of cellulose acylate and the solvent using a halogen-based organic solvent as the solvent, it is preferable to include a step of dissolving the cellulose acylate in the solvent by one or more methods selected from the following (a) or (b). Do.

(a) It swells at -10-39 degreeC and the obtained mixture is heated to 0-39 degreeC.

(b) It swells at -10-39 degreeC, the obtained mixture is heated to 40-240 degreeC by 0.2-30 Mpa, and the heated mixture is cooled to 0-39 degreeC.

Moreover, when cooling a mixture of a cellulose acylate and a solvent using a non-halogen type organic solvent as a solvent, it is preferable to include the process of cooling a mixture to -100-10 degreeC. Moreover, it is preferable to include the process of swelling at -10-55 degreeC in the process before a cooling process, and the process of heating to 0-57 degreeC in the process after cooling.

When the mixture of cellulose acylate and solvent is heated using a halogen-based organic solvent as the solvent, the step of dissolving cellulose acylate in the solvent by at least one method selected from the following (c) or (d) desirable.

(c) It swells at -10-55 degreeC and the obtained mixture is heated to 0-57 degreeC.

(d) It swells at -10-55 degreeC, the obtained mixture is heated to 40-240 degreeC by 0.2-30 Mpa, and the heated mixture is cooled to 0-57 degreeC.

[Formation of the polymer film used for the manufacturing method of this invention]

The polymer film used for the manufacturing method of this invention can be manufactured by the solution casting film forming method using said polymer solution. When performing a solution casting film forming method, a conventional apparatus can be used according to a conventional method. Specifically, after filtering the dope (polymer solution) prepared in the dissolving machine (kiln), it can store once in a storage kiln, defoaming the bubble contained in dope, and finally can prepare it. The dope is kept at 30 ° C., and is passed from the dope outlet to a pressurized die through a pressurized metering gear pump capable of quantitatively feeding the fluid with high precision, for example, according to the rotational speed. It is uniformly flexible (flexible process) on the metal support of the flexible part which travels endlessly in a slit). Next, at the peeling point where the metal support body was almost round, the semi-dry dope film (also called a web) is peeled from a metal support body, and it conveys to a dry zone continuously, and finishes drying, conveying by a roll group. . The detail of the casting | flow_spread process of a solution casting film forming method, and the drying process is also described in pages 120-146 of Unexamined-Japanese-Patent No. 2005-104148, and can be applied also to this invention suitably.

Moreover, the polymer film used for the manufacturing method of this invention can be manufactured by the melt casting film forming method, without using said polymer solution. The melt casting film forming method is a method of casting a polymer by heating it to melt on a support, cooling the film, and forming a film. When the melting point of the polymer or the melting point of the mixture of the polymer and various additives is lower than these decomposition temperatures and higher than the stretching temperature, a melt casting film forming method can be employed. As for the melt casting film forming method, there is disclosed in JP-A-2000-352620.

In this invention, a metal band or a metal drum can be used as a metal support body used at the time of film forming of the polymer film before heat processing. In the case of using a transparent polymer film formed by using a metal band, Rth of the film after heat treatment tends to be lowered, and Rth is negative although it depends on other retardation factors such as the additive. , The film | membrane of | Rth | / Re <0.5 can be manufactured. Moreover, when using the transparent polymer film formed into a film using the metal drum, Rth of the film after heat processing tends to become high, and although it changes with factors which adjust other retardation, such as the said additive, Rth is 0 (zero). It is a part or positive which is close to, and can produce a film which satisfy | fills | Rth / Re <0.5 degree as the case may be. The difference in Rth after the heat treatment of the polymer film used in the production methods of these inventions is caused by the difference in the plane orientation state of the polymer chains present in the film before the heat treatment due to the different external force applied to the web in the film forming process. I guess.

In controlling the retardation of the transparent polymer film produced by the production method of the present invention, it is preferable to control the mechanical history applied to the polymer film before the heat treatment, that is, the external force applied to the polymer web in the film forming process. Specifically, in the case where the transparent polymer film produced by the production method of the present invention exhibits a large Re and a negative Rth, the polymer web is preferably 0.1% or more and less than 15%, more preferably 0.5 to 10. %, More preferably, it is 1 to 8% extending | stretching. Moreover, when manufacturing, conveying the polymer film before heat processing, it is preferable to extend | stretch to the said conveyance direction. The amount of residual solvent of the polymer web at the time of this drawing is computed based on a following formula, and may be 5 to 1000%. It is preferable that the amount of residual solvent is 10 to 200%, It is more preferable that it is 30 to 150%, It is further more preferable that it is 40 to 100%.

Residual Solvent Amount (mass%) = {(M-N) / N} × 100

[Wherein, M represents the mass of the polymer film immediately before being inserted into the stretching zone, and N represents the mass when the polymer film immediately before being inserted into the stretching zone is dried at 110 ° C. for 3 hours.

Moreover, when big Re is shown and positive Rth is shown, a polymer web is extended | stretched preferably 15 to 300%, More preferably, 18 to 200%, More preferably, 20 to 100%. Moreover, when manufacturing, conveying the polymer film before heat processing, it is preferable to extend | stretch to the said conveyance direction. The amount of residual solvent of the polymer web at the time of this extending | stretching is computed based on the said formula, and shall be 5 to 1000%. It is preferable that the amount of residual solvent is 30 to 500%, It is more preferable that it is 50 to 300%, It is further more preferable that it is 80 to 250%.

The draw ratio (extension) of the polymer web at the time of the said stretching can be achieved by the peripheral speed difference of a metal support speed and peeling speed (peel roll draw). By performing such extending | stretching, the expression property of retardation can be adjusted.

When extending | stretching in the state which residual solvent amount is 5% or more, haze becomes difficult to become large, When extending | stretching in the state which residual solvent amount is 1000% or less, the external force applied to a polymer chain is easy to be transmitted, and by the polymer web extending | stretching performed in the state containing the said solvent There exists a tendency for the effect of retardation expression adjustment to become large. In addition, the amount of residual solvent of a polymer web can be suitably adjusted by changing the density | concentration of the said polymer solution, the temperature and speed of a metal support body, the temperature or air volume of a drying wind, the solvent gas concentration in a dry atmosphere, etc.

Moreover, in the process of extending | stretching the said polymer web, it is preferable that the film surface temperature of a web is low from a viewpoint of conveying an external force to a polymer, and it is preferable to make the temperature of a web into (Ts-100)-(Ts-0.1) degreeC, It is more preferable to set it as (Ts-50)-(Ts-1) degreeC, and it is still more preferable to set it as (Ts-20)-(Ts-3) degreeC. Here, Ts represents the surface temperature of the flexible support, and when the temperature of the flexible support is set to a temperature which is partially different, the surface temperature in the center portion of the support is shown.

The polymer web which has been subjected to the stretching step in this manner is subsequently conveyed to the drying zone, and drying is terminated while both ends are clipped with a tenter or conveyed by a roll group.

Thus, as for the residual solvent amount in the film which completed drying, 0-2 mass% is preferable, More preferably, it is 0-1 mass%. This film may be conveyed to a heat processing zone as it is, and may heat-process offline, after winding up a film. The preferred width of the polymer film before the heat treatment is 0.5 to 5 m, more preferably 0.7 to 3 m. Moreover, when winding up a film once, a preferable persimmon length is 300-30000m, More preferably, it is 500-10000m, More preferably, it is 1000-7000m.

It is preferable that it is 100 g / (m <2> * day) or more, as for the water vapor transmission rate of 80 micrometers conversion of the polymer film used for the manufacturing method of this invention formed into a film, it is more preferable that it is 100-1500 g / (m <2> * day), and 200- It is more preferable that it is 1000 g / (m <2> * day), and it is especially preferable that it is 300-800 g / (m <2> * day). In order to prepare the film of this invention which has a water vapor transmission rate of 100 g / (m <2> * day) or more in 80 micrometers conversion, it is preferable to control the hydrophilicity of a polymer suitably, or to reduce the density of a film. As the former method, for example, a method of properly controlling the hydrophilicity of the polymer main chain and introducing a hydrophobic or hydrophilic side chain, etc. may be mentioned. As the latter method, for example, a side chain is added to the polymer main chain. The method of introducing, selecting the kind of solvent used at the time of film forming, controlling the drying rate at the time of film forming, etc. are mentioned.

The moisture permeability in the present invention is a mass change before and after humidity control when the cup containing calcium chloride is covered with a film using a film and left closed at a temperature of 40 ° C. and a relative humidity of 90% for 24 hours (g / (M 2 · day)). In addition, although the water vapor transmission rate rises with the increase of temperature, and it rises with the increase of humidity, the magnitude relationship of the moisture vapor transmission rate between films is unchanged regardless of each condition. For this reason, in this invention, it is based on the value of the said mass change in 40 degreeC and 90% of a relative humidity. In addition, since the moisture permeability decreases with the increase of the film thickness and increases with the decrease of the film thickness, first, the actual moisture permeability is multiplied by the measured film thickness, and the value obtained by dividing it by 80 is referred to as "film". Moisture permeability in terms of thickness of 80 µm ”.

[Preliminary extension]

The solvent is dried, and the film-formed transparent polymer film before heat treatment whose residual solvent amount calculated based on the above formula is less than 5% may be stretched before heat treatment at a temperature T satisfying Tc≤T <Tm ₀ . (Hereinafter, the stretching is also referred to as "preliminary stretching"). By carrying out this preliminary stretching, the expression of Re or Rth in the heat treatment step can be further adjusted. Specifically, within the range to be described later, by lowering the stretching temperature or increasing the stretching ratio, the heat treatment temperature can be set relatively low, or the reach range of Re or Rth can be increased. Moreover, you may include the process different between a preliminary extending process and a heat processing process within the range which does not deviate from the meaning of this invention.

In the production method of the present invention, preliminary stretching is performed at (Tg-20) to (Tg + 50) ° C when the glass transition temperature of the polymer film used in the production method of the present invention is Tg (unit; ° C). It is desirable to. The preliminary stretching temperature is more preferably (Tg-10) to (Tg + 45) ° C, still more preferably Tg to (Tg + 40) ° C, and most preferably (Tg + 5) to (Tg +35) ° C. However, the preliminary stretching temperature does not exceed the crystallization temperature Tc described later. It is preferable to carry out preliminary extending | stretching temperature at the temperature lower than 5 degreeC than Tc, It is more preferable to carry out at temperature lower than 10 degreeC than Tc, It is more preferable to carry out at temperature lower than 15 degreeC Tc, It is more preferable than Tc It is especially preferable to carry out at temperature lower than 20 degreeC, and it is most preferable to carry out at temperature lower than 35 degreeC than Tc.

In the present invention, the glass transition temperature is the boundary temperature at which the mobility of the polymer constituting the transparent polymer film of the present invention is greatly changed. As for the glass transition temperature in this invention, 20 mg of the polymer films used for the manufacturing method of this invention were put into the measuring pan of a differential scanning calorimetry apparatus (DSC), and this was 120 to 30 degreeC at 10 degree-C / min in nitrogen stream. The temperature at which the baseline starts to be knitted from the low temperature side after raising the temperature to 15 ° C. and holding it for 15 minutes, then cooling it to 30 ° C. at −20 ° C./min, then raising the temperature to 30 ° C. to 250 ° C. again. to be.

In the production method of the present invention, it is estimated that by making the polymer film used in the production method of the present invention more than Tc, the structure observed by X-ray diffraction can be grown to adjust the retardation. Since the polymer can be arranged to some extent in the preliminary stretching direction, the structure observed by the X-ray diffraction can be efficiently and anisotropically grown in the heat treatment step described later. In addition, since the preliminary stretching temperature is lower than the heat treatment temperature, the polymer can be oriented without growing the structure observed by the X-ray diffraction, so that the structure observed by the X-ray diffraction is more efficiently observed in the subsequent heat treatment step. It has the advantage of being able to grow. Therefore, it is more preferable that the stretching direction in preliminary stretching and the extending | stretching direction or conveyance direction at the time of heat processing mentioned later match with the viewpoint of the heat processing temperature reduction, or the viewpoint of the reach range of Re or Rth. In contrast, when these directions do not coincide, the reach of Re or Rth can be reduced.

The direction of the preliminary stretching is not particularly limited, and in the case where the polymer film before the heat treatment is conveyed, longitudinal stretching may be performed in the conveying direction or transverse stretching may be performed in a direction orthogonal thereto, but it is preferably longitudinal stretching. Do. The column of heat processing mentioned later can be referred for the method of a longitudinal stretch or a lateral stretch, and a preferable aspect. It is preferable that a preliminary draw ratio is 1 to 500%, 3 to 400% is more preferable, 5 to 300% is still more preferable, 10 to 100% is especially preferable. These preliminary stretching may be performed by single stage, and you may carry out by multiple stages. In addition, the "preliminary draw ratio (%)" here means what is calculated | required by the following formula | equation.

Preliminary draw ratio (%) = 100 × {(length after stretching)-(length before stretching)} / length before stretching

 The stretching rate in the preliminary stretching is preferably 10 to 10000% / min, more preferably 20 to 1000% / min, still more preferably 30 to 800% / min.

[Heat treatment]

The manufacturing method of the transparent polymer film of this invention is characterized by including the process of heat-processing a transparent polymer film at the temperature T (unit; degreeC) which satisfy | fills the conditions of following formula (1). Here, it is preferable to perform heat processing, conveying.

Equation (1): Tc≤T <Tm ₀

In Formula (1), Tc represents the crystallization temperature of the polymer film before heat processing, and a unit is ° C. In the present invention, the crystallization temperature refers to a temperature at which the polymer constituting the transparent polymer film of the present invention forms a regular periodic structure, and when it exceeds this temperature, the structure observed by X-ray diffraction grows. Crystallization temperature in this invention puts 20 mg of polymer films before heat processing into the measuring pan of DSC, heats this from 30 degreeC to 120 degreeC at 10 degreeC / min in nitrogen airflow, hold | maintains for 15 minutes, and is -30 degreeC. It is the start temperature of the exothermic peak observed when cooling at 20 degree-C / min and raising temperature further from 30 degreeC to 300 degreeC after that further. Tc usually appears on the higher temperature side than the glass transition temperature (Tg) mentioned above. For example, the crystallization temperature of the cellulose triacetate film having a total substitution degree of 2.85 increases and decreases depending on additives and film forming conditions, but the crystallization temperature of the cellulose triacetate film having a total substitution degree of 2.92 is about 170 ° C. to be.

In Formula (1), Tm ₀ represents the melting point of the polymer film before the heat treatment, and the unit is ° C. Melting | fusing point in this invention puts 20 mg of polymer films before heat processing into the measurement pan of DSC, heats this from 30 degreeC to 120 degreeC at 10 degreeC / min in nitrogen stream, hold | maintains for 15 minutes, and is -20 to 30 degreeC. It is the start temperature of the observed endothermic peak when cooling at ° C / min and further increasing the temperature from 30 ° C to 300 ° C after that. Tm ₀ usually appears on the higher temperature side than the above-mentioned crystallization temperature (Tc). For example, the melting point of the cellulose triacetate film having a total substitution degree of 2.85 slightly rises and falls depending on additives and film forming conditions, but the melting point of the cellulose triacetate film having a total substitution degree of 2.92 is about 290 ° C. .

The expression property of the retardation of a transparent polymer film can be adjusted by heat-processing a transparent polymer film at the temperature T which satisfy | fills the conditions of Formula (1). As a result, a transparent polymer film having a retardation value, which has not been easy to manufacture conventionally, can be produced by a simple method. In particular, the transparent polymer film of Rth / Re <0.5, which could not be produced without a complicated manufacturing method in the related art, was able to produce a good planar shape with a simple method.

It is preferable that the heat processing temperature in the manufacturing method of this invention satisfy | fills following formula (1-1), It is more preferable to satisfy following formula (1-2), and satisfy | fills following formula (1-3) More preferably. By selecting a temperature that satisfies these equations, there is an advantage that the Re expressionability is increased or, in some cases, the stretching direction and the direction of the slow axis are orthogonal.

Formula (1-1): Tc≤T <Tm _0-5

Equation (1-2): Tc≤T <Tm _0-10

Formula (1-3): Tc + 5≤T <Tm _0-15

Tc≤T <Tm ₀ according to the manufacturing method of the present invention By extending | stretching at the temperature T which satisfy | fills the structure, since the mobility of a polymer chain can be improved, whitening of a film (rising haze) and cutting | disconnection of a film with an increase of draw ratio can be prevented. Moreover, the balance of the thermal relaxation which occurs simultaneously with the aggregation and orientation of a polymer chain can be suitably controlled by adjusting a extending | stretching speed and a draw ratio as mentioned later. Therefore, according to the manufacturing method of this invention, the aggregation and arrangement | positioning of the polymer chain in a film can be advanced highly, and the transparent polymer film with a large elastic modulus, a small change in humidity dimension, and moderate moisture permeability can be manufactured.

It is preferable to perform heat processing in the manufacturing method of this invention, conveying a transparent polymer film. The conveying means of the transparent polymer film is not particularly limited, but as a typical example, means for conveying by nip rolls or suction drums, means for conveying while gripping with a tenter clip (means conveying by open air pressure) ), And the like. Preferable is a means for conveying by a nip roll. Specifically, the aspect which conveys a polymer film by providing a nip roll at least before and after each zone before a heat processing, and passing between the said nip rolls is mentioned.

The conveyance speed is usually 1 to 500 m / min, preferably 5 to 300 m / min, more preferably 10 to 200 m / min, and even more preferably 20 to 100 m / min. When the conveyance speed is 1 m / min or more, which is the lower limit, it tends to be industrially preferable in terms of ensuring sufficient productivity, and when the conveyance speed is 500 m / min or less, which is the upper limit, the crystal growth sufficiently in a practical heat treatment zone length. It tends to be preferable in that it can advance. When the conveyance speed is increased, the coloring of the film tends to be suppressed, and when the conveyance speed is slowed, the heat treatment zone length tends to be shortened. It is preferable to make the conveyance speed (speed of apparatuses, such as a nip roll and suction drum, which determine a conveyance speed) constant during heat processing.

As a method of the heat treatment in the manufacturing method of this invention, the method of letting the inside of the zone of temperature T pass, for example, conveying a transparent polymer film, the method of making hot air match the conveyed transparent polymer film, and the conveyed transparent The method of irradiating a heat ray to a polymer film, the method of making a transparent polymer film contact the roll which heated up, etc. are mentioned.

It is a preferable method to pass the inside of the zone of temperature T, making hot air pass, conveying a transparent polymer film. According to this method, there exists an advantage that a transparent polymer film can be heated uniformly. The temperature inside the zone can be maintained at the temperature T by controlling the heater to a constant temperature while monitoring the temperature sensor, for example. Although the conveyance length of the transparent polymer film in the zone of the temperature T differs depending on the property and conveyance speed of the transparent polymer film to be manufactured, the ratio of (conveyance length) / (width of the transparent polymer film to convey) is usually 0.1 to It is preferable to set it to 100, More preferably, it is 0.5-50, More preferably, it is 1-20. This ratio may be abbreviated as an aspect ratio in this specification. The passage time (heat treatment time) of the zone of the temperature T is usually 0.01 to 60 minutes, preferably 0.03 to 10 minutes, and more preferably 0.05 to 5 minutes. By setting it as said range, the retardation expression is excellent and coloring of a film can be suppressed.

In the manufacturing method of this invention, you may extend | stretch simultaneously with heat processing. Although the extending | stretching direction at the time of heat processing is not restrict | limited, When there is anisotropy in the polymer film before heat processing, it is preferable that it is extending | stretching to the orientation direction of the polymer in the polymer film before heat processing. Here, having anisotropy in a film means that the ratio of the sound wave propagation speed of the direction which maximizes the sound wave propagation speed, and the sound wave propagation speed of the direction orthogonal to this is preferably 1.01-10.0, More preferably, it is 1.1- It is 5.0, More preferably, it is 1.2-2.5. The direction in which the sound wave propagation speed is maximized and the sound wave propagation speed in each direction are prepared by the orientation measuring instrument (SST-2500: Nomura Corporation Co., Ltd.) after the film is humidified for 24 hours at 25 ° C and a relative humidity of 60%. ) Can be obtained as the direction in which the propagation speed of the longitudinal wave vibration of the ultrasonic pulse is maximized and the propagation speed in each direction.

For example, when heat-processing, conveying a transparent polymer film using the apparatus which has a heating zone between two nip rolls, the exit side nip roll of a heating zone rather than the rotation speed of the nip roll of the inlet side of a heating zone. By increasing the rotational speed of, the transparent polymer film can be stretched in the conveying direction (the longitudinal direction). Moreover, it can also extend | stretch by holding both ends of a transparent polymer film with a tenter clip, and passing it through a heating zone, extending this in the direction orthogonal to a conveyance direction (lateral direction). By extending | stretching a transparent polymer film to a conveyance direction during heat processing, retardation expression property can be further adjusted. The draw ratio of a conveyance direction is 0.8-100 times normally, Preferably it is 1.0-10 times, More preferably, it is 1.2-5 times. Moreover, the surface shape of the transparent polymer film after heat processing can be improved by extending | stretching a transparent polymer film in the direction parallel to a conveyance direction during heat processing. The draw ratio of the direction going straight to a conveyance direction is 0.8-10 times normally, Preferably it is 1.0-5 times, More preferably, it is 1.1-3 times. In addition, the draw ratio (%) here means what was calculated | required using the following formula | equation.

Stretch ratio (%) = 100 × {(length after stretching)-(length before stretching)} / length before stretching

Moreover, as for the extending | stretching speed in the said extending | stretching, 10-10000% / min is preferable, More preferably, it is 20-1000% / min, More preferably, it is 30-800% / min.

At the time of heat treatment, the transparent polymer film may be shrunk. It is preferable to perform the said shrinkage | contraction at the time of heat processing. By shrinking the transparent polymer film during the heat treatment, optical properties and / or mechanical properties can be adjusted. The step of shrinking in the width direction can be carried out not only at the time of heat treatment but also at the steps before and after heat treatment. Moreover, the process to shrink | contract in the width direction may be performed by one end, and you may perform a shrinkage process and an extending process repeatedly.

It is preferable that the shrinkage rate at the time of shrinking is 5 to 80%, more preferably 10 to 70%, still more preferably 20 to 60%, and most preferably 25 to 50%. In addition, although a shrinkage direction is not specifically limited, When the polymer film before heat processing is conveyed and produced, it is preferable to implement in the direction orthogonal to the said conveyance direction. Moreover, when extending | stretching (preliminary extending | stretching etc.) before contraction, it is preferable to shrink | contract in the direction orthogonal to the said extending | stretching direction. The shrinkage rate can be controlled by adjusting the heat treatment temperature or adjusting the external force applied to the film. Specifically, in the case where the end portion of the film is held by the tenter clip, it can be controlled by the width expansion ratio of the rail or the like. Moreover, when the edge part of a film is not fixed and it is hold | maintained only by the apparatus which fixes films, such as a nip roll, to a conveyance direction, adjustment of the distance between apparatuses to fix in a conveyance direction, and the tension applied to a film In addition, it can control by adjustment of the amount of heat provided to a film. The shrinkage in the width direction measures the entire width immediately before and immediately after the film shrinks, and is obtained from the following equation.

Shrinkage (%) in the width direction = 100 × (total width immediately after contraction-total contraction) / total width immediately before contraction

The process of heat-processing a transparent polymer film at temperature T may be performed only once, and may be performed multiple times in the manufacturing method of this invention. Performing a plurality of times means that after the completion of the previous heat treatment, the temperature is once lowered to less than Tc, and thereafter, the temperature is set to Tc or more and less than Tm ₀ , and then the heat treatment is performed. When heat-processing multiple times, it is preferable to satisfy | fill the range of said draw ratio at the stage in which all heat processing is completed. 3 times or less are preferable, as for the heat processing in the manufacturing method of this invention, 2 times or less are more preferable, and 1 time is the most preferable.

[Cooling after heat treatment]

The polymer film after heat treatment is cooled to a temperature below Tc. The cooling temperature is not particularly limited, but the film is preferably cooled to 100 to 1,000,000 ° C / minute, more preferably 1,000 to 100,000 ° C / minute, still more preferably 3,000 to 50,000 ° C / minute. It is preferable that the temperature width which cools a film at such a cooling rate is 50 degreeC or more, It is more preferable that it is 100-300 degreeC, It is further more preferable that it is 150-280 degreeC, It is especially preferable that it is 180-250 degreeC.

Thus, by adjusting a cooling rate, the expression property of the retardation of the transparent polymer film (especially a cellulose acylate film) obtained can be further adjusted. Specifically, by increasing the cooling rate, the expression of retardation can be improved. Moreover, distribution of the polymer chain orientation of the thickness direction in a cellulose acylate film can be reduced, and the humidity curl of a film can be suppressed. Such an effect can be more fully obtained by controlling the temperature range to be cooled at a relatively high cooling rate to the above preferred range. As a result, for example, a transparent polymer film (in particular, a cellulose acylate film) that satisfies the relational expression of | Rth | / Re <0.5 and Re≥30 can be obtained. Also, a transparent polymer film satisfying the relation of both Rth / Re <0.5 and Re≥60, a transparent polymer film satisfying the relation of both Rth / Re <0.5 and Re≥100, Rth // The transparent polymer film which satisfies both the relational formulas of Re <0.5 and Re≥150, and the transparent polymer film which satisfies both the relations of | Rth | / Re <0.5 and Re≥200 can also be obtained.

The said cooling rate forms the cooling zone maintained at the temperature lower than a heating zone after a heating zone, and conveys a transparent polymer film to these zones sequentially, makes a cooling roll contact a film, or sprays cooling air to a film Or by immersing the film in a cooled liquid. The cooling rate does not always have to be constant in the cooling process, and the cooling rate may be increased at the beginning and the end of the cooling process, while increasing the cooling rate therebetween. A cooling rate can be calculated | required by measuring the temperature of several points with the thermocouple arrange | positioned on the film film surface as described in the Example mentioned later.

[Extraction after heat treatment]

In the manufacturing method of this invention, you may extend | stretch following heat processing of a transparent polymer film. The stretching performed after the heat treatment may be performed after the transparent polymer film is cooled to a temperature below Tc after the heat treatment, or may be performed without cooling while maintaining the heat treatment temperature. Once the polymer film is cooled, the cooling may be in a state of naturally cooling to a temperature below Tc, or may be in a state of forced cooling to a temperature below Tc. Moreover, it may be in the state heated once less than Tc after cooling once. It is preferable that cooling temperature at the time of cooling a film once is 50 degreeC or more lower than the said heat processing temperature, It is more preferable that it is 100-300 degreeC low, It is still more preferable that it is 150-250 degreeC low. It exists in the tendency which can control Rth / Re value of the film after heat processing easily by making cooling temperature 50 degreeC or more lower than heat processing temperature. Moreover, it is preferable to extend, after cooling a film to cooling temperature once, after heating to temperature below Tc again. It is preferable that the difference of the said heat processing temperature and extending | stretching temperature is 1 degreeC or more, 10-200 degreeC is more preferable, 30-150 degreeC is still more preferable, 50-100 degreeC is especially preferable. By setting this temperature difference appropriately, the Rth / Re value can be controlled. Specifically, when the difference between the heat treatment temperature and the stretching temperature is increased, the Rth / Re value tends to increase, and when the difference is small, the change in the Rth / Re value tends to decrease.

As an extending | stretching method, the method etc. which were described in the description of extending | stretching in said heat processing can be employ | adopted. Stretching may be performed in one stage or may be performed in multiple stages. It is a method of extending | stretching in a conveyance direction by changing the rotation speed of said nip roll, and a method of extending | stretching by holding both ends of a polymer film with a tenter clip, and extending this in the direction orthogonal to a conveyance direction. Particularly preferred is not stretching at the time of heat treatment, or stretching in the conveying direction by changing the rotational speed of the nip roll, and after heat treatment, both ends of the polymer film are gripped with a tenter clip and this is perpendicular to the conveying direction. It is an aspect extended by broadening.

The draw ratio can be appropriately set according to the retardation required for the transparent polymer film, preferably 1 to 500%, more preferably 3 to 400%, still more preferably 5 to 300%, and particularly preferably 10 to 100%. desirable. The stretching speed is preferably 10 to 10000% / min, more preferably 20 to 1000% / min, and even more preferably 30 to 800% / min.

By extending | stretching after heat processing, Re and Rth of the transparent film obtained can be adjusted. For example, by increasing the stretching temperature after heat treatment, Rth can be reduced without changing Re much. Moreover, Re can be reduced and Rth can be raised by making the draw ratio after heat processing high. Since these show almost linear correlations, it is easy to achieve the target Re and Rth by appropriately selecting the stretching conditions after the heat treatment.

After completion of the heat treatment, Re or Rth of the transparent polymer film in a state before stretching is not particularly limited.

<< transparent polymer film >>

(Optical characteristics of the transparent polymer film of the present invention)

According to the manufacturing method of said invention, the transparent polymer film by which retardation was controlled can be obtained. Specifically, according to the manufacturing method of this invention, the transparent polymer film in which retardation was expressed favorably can be obtained. In particular, the transparent polymer film of | Rth | Re <0.5 which was not easy to manufacture by the conventional manufacturing method can be manufactured by a comparatively simple method. | Rth | / Re of the transparent polymer film of this invention becomes like this. More preferably, it is 0.4 or less, More preferably, it is 0.3 or less, Especially preferably, it is 0.2 or less.

(Retardation)

In the present specification, Re and Rth (unit; nm) are obtained by the following method. First, the film was moisturized at 25 ° C. and 60% relative humidity for 24 hours, and then a prism coupler (MODEL2010 Prism Coupler manufactured by Metricon) was used, and at 25 ° C. and 60% relative humidity, a solid laser of 532 nm was used. The average refractive index n shown by Formula (a) is calculated | required.

Formula (a): n = (n _TE x 2 + n _TM ) / 3

[Wherein n _TE Is the refractive index measured by the polarization of a film plane direction, _nTM Is the refractive index measured by polarization in the film plane normal direction.]

In this specification, Re ((lambda)) and Rth ((lambda)) represent in-plane retardation and retardation of thickness direction in wavelength (lambda) (unit: nm), respectively. Re (λ) is measured by injecting light having a wavelength of λ nm in the film normal direction in KOBRA 21ADH or WR (manufactured by Oji Measuring Instruments Co., Ltd.).

When the film to be measured is represented by the refractive index ellipsoid of one axis or two axes, Rth (λ) is calculated by the following method.

Rth (λ) refers to Re (λ) as the in-plane slow axis (determined by KOBRA 21ADH or WR) as the inclination axis (rotation axis) (when there is no ground axis, any direction in the film plane is the rotation axis). 11 points of light were measured by injecting light having a wavelength of λ nm from the inclined direction in 10 ° steps from the normal direction to the film normal direction of KOBRA 21ADH or WR is calculated based on the refractive index and the input film thickness value.

In the above, when there is no description regarding (lambda) in particular, and only Re and Rth are described, the value measured using the light of wavelength 590nm is shown. Moreover, in the case of a film having a direction in which the value of retardation becomes zero (zero) at any inclination angle from the normal axis direction as the in-plane slow axis, the retardation value at the inclination angle larger than the inclination angle is After changing the sign to negative, KOBRA 21ADH or WR is calculated.

In addition, the slow axis is set as the inclination axis (rotation axis) (when there is no ground axis, any direction in the film plane is used as the rotation axis), and the retardation value is measured from any inclined two directions, and the value and the average refractive index are measured. And based on the input film thickness value, Rth can also be computed from following formula (b) and formula (c).

Formula (b):

[In formula, Re ((theta)) shows the retardation value in the direction which inclined angle (theta) from a normal line direction. In addition, nx represents the refractive index of the slow-axis direction in surface inside, ny represents the refractive index of the direction orthogonal to nx in surface, nz represents the refractive index of the direction orthogonal to nx and ny, d is the film thickness of a film Is displayed.]

Formula (c): Rth = ((nx + ny) / 2-nz) × d

When the film to be measured cannot be expressed by a refractive index ellipsoid of one axis or two axes, or a film without an so-called optical axis, Rth (λ) is calculated by the following method.

Rth (λ) is 10 degrees from -50 to +50 degrees with respect to the film normal direction using Re (λ) as the in-plane slow axis (judged by KOBRA 21ADH or WR) as the inclined axis (rotation axis). 11 points of light were measured by injecting light having a wavelength of λ nm from the inclined direction, and KOBRA 21ADH or WR was calculated based on the measured retardation value, the average refractive index, and the input film thickness value.

By inputting these average refractive indices and film thickness, KOBRA 21ADH or WR calculates nx, ny, nz. From this calculated nx, ny, and nz, Nz = (nx-nz) / (nx-ny) is further calculated.

In the present invention, the retardation values in the in-plane direction and the film thickness direction when the relative humidity is H (unit;%): Re (H%) and Rth (H%) are 25 ° C. and relative humidity H%. After humidifying for 24 hours at, the retardation value when the measurement wavelength at the relative humidity H% is 590 nm is measured and calculated at 25 ° C. and the relative humidity H% in the same manner as described above.

(Humidity dependence)

It is preferable that the retardation value in the case of changing the humidity of the transparent polymer film of this invention satisfy | fills the following relational formulas.

Re (10%)-Re (80%) │ <50, also,

Rth (10%)-Rth (80%) │50

Moreover, it is more preferable to satisfy the following relational expressions.

Re (10%)-Re (80%) │ <30, also,

Rth (10%)-Rth (80%) │ <40

Moreover, it is more preferable to satisfy the following relational formula.

Re (10%)-Re (80%) │ <20,

Rth (10%)-Rth (80%) │ <30

Moreover, it is most preferable to satisfy the following relationship.

Re (10%)-Re (80%) │10,

Rth (10%)-Rth (80%) │ <15

Moreover, it is preferable that the retardation value at the time of changing the humidity of the transparent polymer film of this invention also satisfy | fills the following relational formula.

Re (10%)-Re (80%) / Re <3, also,

Rth (10%)-Rth (80%) │ / Rth <3

Moreover, it is more preferable to satisfy the following relational expressions.

Re (10%)-Re (80%) │ / Re <1, also,

Rth (10%)-Rth (80%) │ / Rth <1

Moreover, it is more preferable to satisfy the following relational formula.

Re (10%)-Re (80%) / Re <0.5, also,

Rth (10%)-Rth (80%) │ / Rth <0.7

Moreover, it is most preferable to satisfy the following relationship.

Re (10%)-Re (80%) / Re <0.2, also,

Rth (10%)-Rth (80%) │ / Rth <0.4

By controlling the retardation value in the case where the humidity is changed, the retardation change in the case where the external environment is changed can be reduced, and a highly reliable liquid crystal display device can be provided.

(Ground shaft)

As for the transparent polymer film of this invention, it is preferable that the angle ((theta)) which the conveyance direction at the time of manufacture and the slow axis of Re of a film forms is 0 +/- 10 degrees or 90 +/- 10 degrees, and 0 +/- 5 degrees or 90 +/- 5 degrees It is more preferable that it is more preferable, It is still more preferable that it is 0 +/- 3 degree or 90 +/- 3 degree, It is preferable that it is 0 +/- 1 degree or 90 +/- 1 degree, and it is most preferable that it is 90 +/- 1 degree depending on case.

(Film thickness)

20 micrometers-180 micrometers are preferable, as for the film thickness of the transparent polymer film of this invention, 40 micrometers-160 micrometers are more preferable, and 60 micrometers-140 micrometers are still more preferable. The film thickness of 20 micrometers or more is preferable from the handling property at the time of processing with a polarizing plate, etc., and the curl suppression surface of a polarizing plate. Moreover, as for the film thickness variation of the transparent polymer film of this invention, it is preferable that both a conveyance direction and the width direction are 0 to 2%, 0 to 1.5% are more preferable, It is especially preferable that it is 0 to 1%.

(Moisture permeability)

It is preferable that the water vapor transmission rate of the transparent polymer film of this invention is 100 g / (m <2> * day) or more in conversion of 80 micrometers. By using the film which made the said 80 micrometers water vapor transmission rate 100 g / (m <2> * day) or more, it becomes easy to adhere directly to a polarizing film. As a water vapor transmission rate of said 80 micrometers conversion, 100-1500g / (m <2> * day) is more preferable, 200-1000g / (m <2> * day) is more preferable, 300-800g / (m <2> * day) is more preferable.

Moreover, when using the transparent polymer film of this invention as an outer protective film which is not arrange | positioned between a polarizing film and a liquid crystal cell as mentioned later, the water vapor transmission rate of the transparent polymer film of this invention is 500 g / (m <2> in 80 micrometers conversion. It is preferably less than day), more preferably 100 to 450 g / (m 2 · day), still more preferably 100 to 400 g / (m 2 · day), and most preferably 150 to 300 g / (m 2 · day). By doing in this way, durability of a polarizing plate with respect to humidity or wet heat improves, and the liquid crystal display device with high reliability can be provided.

(Configuration of Transparent Polymer Film)

Although the single layer structure may be sufficient as the transparent polymer film of this invention, and may be comprised by multiple layers, it is preferable that it is a single layer structure. Here, the film which is a "single layer structure" does not have the some film material attached, but means one piece of polymer film. And the case where one polymer film is manufactured from a some polymer solution sequentially using a casting | flow_spread system or a covalent smoke system is included. In this case, the polymer film which has distribution in the thickness direction can be obtained by adjusting the kind and compounding quantity of an additive, the molecular weight distribution of a polymer, the kind of a polymer, etc. suitably. Moreover, what has various functional parts, such as an optically anisotropic part, an anti-glare part, a gas barrier part, a moisture resistance part, in these one film is also included.

(Surface treatment)

By surface-treating suitably to the transparent polymer film of this invention, the adhesion of each functional layer (for example, an undercoat layer, a white layer, and an optically anisotropic layer) can be improved. The surface treatment includes glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, saponification treatment (acid saponification treatment, alkali saponification treatment), and glow discharge treatment and alkali saponification treatment are particularly preferable. "Glow discharge treatment" here is a process of performing a plasma process on the film surface in presence of a plasma excitation gas. The detail of these surface treatment methods is described in the invention association publication publication (Publication Publication No. 2001-1745, published March 15, 2001, invention association), and can be used suitably.

In order to improve the adhesion between the film surface and the functional layer, in addition to the surface treatment or instead of the surface treatment, an undercoat (adhesive layer) may be formed on the transparent polymer film of the present invention. About the above-mentioned undercoat, there are descriptions on page 32 of the Invention Association Publication (Publication No. 2001-1745, issued March 15, 2001, Invention Association), and these can be used as appropriate. Moreover, about the functional layer formed on a cellulose acylate film, description is disclosed in pages 32-45 of the invention association publication publication (published publication no. 2001-1745, issued March 15, 2001, invention association), What is described here can be used suitably on the transparent polymer film of this invention.

<< phase difference film >>

The transparent polymer film of this invention can be used as retardation film. In addition, a "phase difference film" generally means an optical material which is used for display apparatuses, such as a liquid crystal display device, and has optical anisotropy, and has the same meaning as a retardation plate, an optical compensation film, an optical compensation sheet, etc. In a liquid crystal display device, a retardation film is used for the purpose of improving the contrast of a display screen, or improving a viewing angle characteristic or a color.

By using the transparent polymer film of this invention, the retardation film which freely controlled Re value and Rth value can be manufactured easily.

In addition, a plurality of transparent polymer films of the present invention may be laminated, or the transparent polymer film of the present invention and a film other than the present invention may be laminated, and Re or Rth may be appropriately adjusted and used as a retardation film. Lamination | stacking of a film can be performed using an adhesive or an adhesive agent.

Moreover, in some cases, the transparent polymer film of the present invention may be used as a support for the retardation film, and an optically anisotropic layer made of liquid crystal or the like may be formed thereon and used as the retardation film. The optically anisotropic layer applied to the retardation film of this invention may be formed, for example from the composition containing a liquid crystalline compound, may be formed from the polymer film which has birefringence, and may be formed from the transparent polymer film of this invention.

As said liquid crystalline compound, a discotic liquid crystalline compound or a rod-like liquid crystalline compound is preferable.

[Discotic liquid crystalline compound]

Examples of discotic liquid crystalline compounds which can be used as the liquid crystalline compounds in the present invention include various literatures (eg, C. Destrade et al., Mol. Crysr. Liq. Crist., Vol. 71, page 111). (1981); edited by Nippon Chemical Society, Quarterly Chemistry Summary, No. 22, Chemistry of Liquid Crystals, Chapter 5, Chapter 10, Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page 2655 (1994)).

In the optically anisotropic layer, the discotic liquid crystalline molecules are preferably fixed in an alignment state, and most preferably, are fixed by a polymerization reaction. Moreover, about the superposition | polymerization of a discotic liquid crystalline molecule, Unexamined-Japanese-Patent No. 8-27284 has description. In order to fix a discotic liquid crystalline molecule by superposition | polymerization, it is necessary to couple a polymeric group as a substituent to the disk-shaped core of a discotic liquid crystalline molecule. However, when a polymeric group is directly connected to a disk-shaped core, it becomes difficult to maintain an orientation state in a polymerization reaction. Thus, a linking group is introduced between the discotic core and the polymerizable group. Discotic liquid crystalline molecules having a polymerizable group are disclosed in Japanese Patent Laid-Open No. 2001-4387.

[Stand-like liquid crystalline compound]

Examples of the rod-like liquid crystalline compound which can be used as the liquid crystalline compound in the present invention include azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, Cyanophenylcyclohexane, cyano substituted phenylpyrimidines, alkoxy substituted phenylpyrimidines, phenyldioxanes, tolans and alkenylcyclohexylbenzonitriles. Moreover, as said rod-like liquid crystalline compound, not only the low molecular liquid crystalline compound mentioned above but a polymeric liquid crystalline compound can also be used.

In the optically anisotropic layer, the rod-like liquid crystalline molecules are preferably fixed in an aligned state, and most preferably fixed by a polymerization reaction. Examples of polymerizable rod-like liquid crystalline compounds that can be used in the present invention are described, for example, in Makromol. Chem., 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. 4,683,327, 5,622,648, 5,770,107, International Publication 95/22586 Brochure, 95/24455 Brochure, 97/00600 Brochure, 98/23580 Brochure, 98/52905 Brochure , Japanese Unexamined Patent Application Publication Nos. 1-272551, 6-16616, 7-110469, 11-80081, Japanese Unexamined Patent Publication No. 2001-328973, and the like.

<< polarizing plate >>

The transparent polymer film or retardation film of this invention can be used as a protective film of a polarizing plate (polarizing plate of this invention). The polarizing plate of this invention consists of a polarizing film and two polarizing plate protective films (transparent polymer film) which protect both surfaces, and the transparent polymer film or retardation film of this invention can be used as at least one polarizing plate protective film.

When using the transparent polymer film of this invention as said polarizing plate protective film, the said transparent polymer film of this invention is subjected to the said surface treatment (it describes also in Unexamined-Japanese-Patent No. 6-94915, Unexamined-Japanese-Patent No. 6-118232). It is preferable to hydrate, and it is preferable to perform a glow discharge process, a corona discharge process, or an alkali saponification process, for example. In particular, when the polymer constituting the transparent polymer film of the present invention is cellulose acylate, alkali saponification treatment is most preferably used as the surface treatment.

As the polarizing film, for example, a polyvinyl alcohol film immersed in an iodine solution and stretched can be used. When using the polarizing film immersed in the iodine solution and extending | stretching a polyvinyl alcohol film, the surface treatment surface of the transparent polymer film of this invention can be directly attached to both surfaces of a polarizing film using an adhesive agent. In the manufacturing method of this invention, it is preferable that the said transparent polymer film adheres directly with a polarizing film in this way. As the adhesive, an aqueous solution of polyvinyl alcohol or polyvinyl acetal (for example, polyvinyl butyral) or latex of a vinyl polymer (for example, polybutyl acrylate) may be used. Particularly preferred adhesives are aqueous solutions of fully saponified polyvinyl alcohol.

Generally, since a liquid crystal cell is formed between two polarizing plates, a liquid crystal display device has four polarizing plate protective films. Although the transparent polymer film of this invention may be used for any one of four polarizing plate protective films, the transparent polymer film of this invention is a protective film arrange | positioned between the polarizing film in a liquid crystal display device, and a liquid crystal layer (liquid crystal cell). It can be used especially advantageously. Moreover, a transparent hard coat layer, an antiglare layer, an antireflection layer, etc. can be formed in the protective film arrange | positioned on the opposite side of the transparent polymer film of this invention across the said polarizing film, and especially the display surface outermost surface of a liquid crystal display device It is preferably used as a polarizing plate protective film.

<< liquid crystal display device >>

The transparent polymer film, retardation film, and polarizing plate of this invention can be used for the liquid crystal display device of various display modes. Each liquid crystal mode in which these films are used is demonstrated below. Among these modes, the transparent polymer film, the retardation film and the polarizing plate of the present invention are particularly preferably used for the liquid crystal display device of the VA mode and the IPS mode. These liquid crystal display devices may be any of a transmissive type, a reflective type, and a transflective type.

(TN type liquid crystal display device)

You may use the transparent polymer film of this invention as a support body of the retardation film of the TN type liquid crystal display device which has the liquid crystal cell of TN mode. TN mode liquid crystal cells and TN type liquid crystal display devices have been well known for a long time. About retardation film used for a TN type liquid crystal display device, Unexamined-Japanese-Patent No. 3-9325, Unexamined-Japanese-Patent No. 6-148429, Unexamined-Japanese-Patent No. 8-50206, and Unexamined-Japanese-Patent No. 9- In addition to the publications of No. 26572, Morori et al. (Jpn. J. Appl. Phys. Vol. 36 (1997) p. 143 or Jpn. J. Appl. Phys. Vol. 36 (1997) p. 1068) There is a description.

(STN type liquid crystal display device)

You may use the transparent polymer film of this invention as a support body of the retardation film of STN type liquid crystal display device which has a liquid crystal cell of STN mode. Generally in STN type liquid crystal display devices, the rod-like liquid crystalline molecules in the liquid crystal cell are twisted in the range of 90 to 360 degrees, and the product of the refractive index anisotropy (Δn) and the cell gap (d) of the rod-shaped liquid crystal molecules is Δnd. It exists in the range of 300-1500 nm. About retardation film used for STN type liquid crystal display device, it describes in Unexamined-Japanese-Patent No. 2000-105316.

(VA type liquid crystal display device)

The transparent polymer film of this invention is used especially advantageously as a support body of retardation film and retardation film of VA type liquid crystal display device which has a liquid crystal cell of VA mode. The VA type liquid crystal display device may be, for example, an orientation-divided system as described in JP-A-10-123576. In these aspects, the polarizing plate using the transparent polymer film of the present invention contributes to enlarged viewing angle and improvement of contrast.

(IPS type liquid crystal display device and ECB type liquid crystal display device)

The transparent polymer film of this invention is used especially advantageously as a protective film of the retardation film, the support body of retardation film, or polarizing plate of IPS type liquid crystal display device and ECB type liquid crystal display device which have a liquid crystal cell of IPS mode and ECB mode. These modes are embodiments in which the liquid crystal material is oriented almost in parallel during black display, and the black display is performed by aligning liquid crystal molecules in parallel with the substrate surface in a voltage-free state. In these aspects, the polarizing plate using the transparent polymer film of the present invention contributes to enlarged viewing angle and quantity of contrast.

(OCB type liquid crystal display device and HAN type liquid crystal display device)

The transparent polymer film of this invention is advantageously used also as a support body of the retardation film of the OCB type liquid crystal display device which has a liquid crystal cell of OCB mode, or the HAN type liquid crystal display device which has a liquid crystal cell of HAN mode. In the retardation film used for an OCB type liquid crystal display device or an HAN type liquid crystal display device, it is preferable that the direction which the absolute value of retardation becomes minimum does not exist in the surface of a retardation film nor a normal direction. The optical properties of the retardation film used for the OCB type liquid crystal display device or the HAN type liquid crystal display device are also 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. The retardation film used for an OCB type liquid crystal display device or an HAN type liquid crystal display device is described in Unexamined-Japanese-Patent No. 9-197397. In addition, the paper by Mori et al. (Jpn. J. Appl. Phys. Vol. 38 (1999) p. 2837) is described.

(Reflective liquid crystal display)

The transparent polymer film of the present invention is advantageously used as a retardation film of a TN type, STN type, HAN type, and GH (Guest-Host) type reflective liquid crystal display device. These display modes have long been well known. About a TN type reflective liquid crystal display device, Unexamined-Japanese-Patent No. 10-123478, the international publication 98/48320 pamphlet, and the Japan patent 3030277 are described. Retardation film used for a reflective liquid crystal display device is described in the international publication 00/65384 pamphlet.

(Other liquid crystal display device)

The transparent polymer film of this invention is advantageously used also as a support body of the retardation film of the ASM type liquid crystal display device which has a liquid crystal cell of ASM (Axially Symmetric Aligned Microcell) mode. The liquid crystal cell of ASM mode has the characteristic that the thickness of the cell is hold | maintained by the resin spacer which can be adjusted. The other property is the same as that of the liquid crystal cell of TN mode. A liquid crystal cell of the ASM mode and an ASM type liquid crystal display device are described in Kume et al. (Kume et al., SlD 98 Digest 1089 (1998)).

(Hard coat film, antiglare film, antireflection film)

You may apply the transparent polymer film of this invention to a hard coat film, an anti-glare film, and an antireflection film as needed. For the purpose of improving the visibility of flat panel displays such as LCD, PDP, CRT, EL, etc., one or both of a hard coat layer, an antiglare layer, and an antireflection layer can be provided on one or both surfaces of the transparent polymer film of the present invention. . Preferred embodiments as such anti-glare films and anti-reflection films are described in detail in pages 54 to 57 of the Invention Association Publication (Publication No. 2001-1745, issued March 15, 2001, Invention Association). The transparent polymer film of the invention can also be preferably used.

<< measurement method >>

First, the measuring method and evaluation method of the characteristic used by the Example and the comparative example are shown below.

[Degree of substitution]

Acyl substitution degree of cellulose acylate is Carbohydr. Res. It was determined by ¹³ C-NMR by the method described in 273 (1995) 83-91 (Tezuka et al.).

[Retardation]

Five points in the width direction (center, end (5% of the total width from each end), and two points in the middle and the middle part of the end) were sampled every 100 m in the longitudinal direction, and a 2 cm square sample was taken out. The average value of each point of the retardation value evaluated in accordance with the above-described method was obtained, and Re, Rth, Re (10%), Re (80%), Rth (10%), and Rth (80%) were obtained, respectively. ΔRe and ΔRth were calculated from the following formulas (iii) and (iii), and ΔRe / Re and ΔRth / Rth were further calculated and listed in Table 1.

Formula (i): ΔRe = │Re (10%)-Re (80%) │

Formula (VIII): ΔRth = │Rth (10%)-Rth (80%) │

In addition, the difference between the maximum value and the minimum value of the deviation (unit: °, -45 to + 45 ° can be taken) from the conveying direction or the direction orthogonal to the slow axis direction at each position is determined. It was set as the fluctuation range in the slow axis direction.

In addition, in Table 3, Table 5, and Table 6, the following method was used for evaluation of retardation value.

First, after humidifying the film at 25 ° C and 60% RH for 24 hours, a prism coupler (MODEL2010 Prism Coupler: manufactured by Metricon) was used, and a 632.8 nm He-Ne laser was used at 25 ° C and 60% RH. The average refractive index (n) represented by following formula (a) was calculated | required.

Formula (a): n = (n _TE x 2 + n _TM ) / 3

[Wherein n _TE Is the refractive index measured at the polarization in the film plane direction, and n _TM is the refractive index measured at the polarization in the film plane normal direction.]

Subsequently, the humidified film was subjected to a birefringence measuring apparatus (ABR-10A: manufactured by Uniopt Co., Ltd.) at 25 ° C and 60% relative humidity to adjust the direction perpendicular to the sample film surface and the slow axis in the film plane. The direction of the slow axis and the retardation value were measured using a 632.8 nm He-Ne laser from a direction inclined ± 40 ° from the film plane normal as the tilt axis (rotation axis), and nx using the average refractive index obtained above. , ny, and nz were calculated, respectively, and the retardation value Re of the in-plane direction and the retardation value Rth of the film thickness direction which were respectively represented by following formula (b) and (c) were computed.

Formula (b): Re = (nx-ny) × d

Formula (c): Rth = {(nx + ny) / 2-nz} × d

[Wherein nx is a refractive index in the slow axis (x) direction in the film plane, ny is a refractive index in the direction orthogonal to the x direction in the film plane, and nz is a refractive index in the film thickness direction (film plane normal direction) of the film and d is film thickness (nm). The slow axis is the direction in which the refractive index is maximum in the film plane.]

[Variation in Ground Axis]

Maximum deviation of the deviation (unit: °, -45 to + 45 °) from the transport direction or the direction orthogonal to the slow axis direction of each sample taken out in the same manner as the retardation measurement described above. The difference between a value and a minimum value was made into the fluctuation range of the slow axis direction.

[Glass Transition Temperature (Tg)]

20 mg of the polymer film before the heat treatment was placed in a measuring pan of DSC, which was heated at 30 ° C to 120 ° C at 10 ° C / min in a nitrogen stream, and held for 15 minutes, and then cooled to -20 ° C / min to 30 ° C. Then, it heated up again from 30 degreeC to 250 degreeC, and made the temperature which a baseline starts to knit from low temperature as Tg of the polymer film before heat processing.

[Tm ₀ ]

20 mg of the polymer film before the heat treatment was placed in a DSC measuring pan, and this was heated to 30 ° C. to 120 ° C. at 10 ° C./min in a nitrogen stream, held for 15 minutes, and then cooled to −20 ° C./min to 30 ° C., Furthermore, the start temperature of the endothermic peak shown when the temperature was further raised from 30 ° C to 300 ° C was then set to Tm ₀ of the polymer film before the heat treatment.

[Tc]

20 mg of the polymer film before the heat treatment was placed in a DSC measuring pan, which was heated at 30 ° C. to 120 ° C. at 10 ° C./min in a nitrogen stream, held for 15 minutes, and then cooled to −20 ° C./min to 30 ° C. Furthermore, after that, the onset temperature of the exothermic peak which appeared when it heated up from 30 degreeC to 300 degreeC was made into Tc of the polymer film before heat processing.

[Degree of Polymerization]

After absolute manufacture of the produced cellulose acylate, about 0.2 g was precisely weighed and dissolved in 100 mL of a mixed solvent of dichloromethane: ethanol = 9: 1 (mass ratio). The number of seconds of falling was measured at 25 degreeC with the Ostwald viscometer, and polymerization degree (DP) was calculated | required by the following formula | equation.

η _rel = T / T ₀

[η] = ln (η _rel ) / C

DP = [η] / Km

[Wherein T is the number of seconds to drop the measurement sample, T ₀ Will fall seconds, ln is the natural logarithm of the solvent alone, C is the concentration (g / L), Km is 6 × 10 ^{- 4} a].

[Polarization degree]

The transmittance | permeability Tp at the time of superimposing the absorption axes parallel to the manufactured two polarizing plates, and the transmittance | permeability Tc at the time of superimposing and superimposing the absorption axes were measured, and the polarization degree P represented by a following formula was computed.

Polarization degree (P) = ((Tp-Tc) / (Tp + Tc)) ^0.5

[Moisture permeability]

The moisture permeability in the present invention is a mass change before and after humidity control when the cup containing calcium chloride is covered with a film using a film and left closed at a temperature of 40 ° C. and a relative humidity of 90% for 24 hours (g / (M 2 · day)).

[Face shape of film]

The surface of the transparent polymer film was visually observed and evaluated according to the following evaluation scale.

(Double-circle): The surface shape of a film was favorable and was applicable suitably as an optical film.

(Circle): Although the some ups and downs were confirmed in a film, it was what was applicable suitably as an optical film.

X: Remarkable ups and downs arise in a film, or the whole surface is cloudy, and it was not applicable to an optical film.

[Haze]

5 points in the width direction of the film (the middle part of the film, the end portion (the position of 5% of the total width respectively from both ends), and the middle part of the middle part and the end part 2 points) were sampled and evaluated according to the above-described method. The average value was computed and the haze value was calculated | required.

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples. Materials, usage amounts, ratios, treatment contents, treatment procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the specific example shown below.

Synthesis Example 1 Synthesis of Cellulose Acetate Propionate

150 g of cellulose (hardwood pulp) and 75 g of acetic acid were put into a 5 L detachable flask to which a reflux device as a reaction container was attached, and stirred vigorously for 2 hours while heating in an oil bath adjusted to 60 ° C. The cellulose subjected to such pretreatment swelled and pulverized to exhibit fluff shape. The reaction vessel was placed in a 2 ° C ice water bath for 30 minutes to cool.

Separately, a mixture of 1545 g of propionic anhydride and 10.5 g of sulfuric acid was prepared as an acylating agent, cooled to −30 ° C., and then added to a reaction vessel containing cellulose subjected to the above pretreatment at one time. After 30 minutes had elapsed, the obscene temperature was gradually increased, and after 2 hours had elapsed from the addition of the acylating agent, the temperature was adjusted to 25 ° C. The reaction vessel was cooled in an ice water bath at 5 ° C, and after 0.5 hours from the addition of the acylating agent, the internal temperature was adjusted to 10 ° C and 2 hours afterwards so that the internal temperature was 23 ° C, the internal temperature was maintained at 23 ° C, and stirred for another 3 hours. It was. The reaction vessel was cooled in an ice bath of 5 ° C., and 120 g of 25 mass% hydrous acetic acid cooled to 5 ° C. was added over 1 hour. The internal temperature was raised to 40 ° C. and stirred for 1.5 hours. Subsequently, a solution obtained by dissolving twice the molar amount of magnesium acetate tetrahydrate in 50% by mass hydrous acetic acid was added to the reaction vessel, followed by stirring for 30 minutes. 1 L of 25 mass% hydrous acetic acid, 500 mL of 33 mass% hydrous acetic acid, 1 L of 50 mass% hydrous acetic acid, and 1 L of water were added in this order, and cellulose acetate propionate was precipitated. Precipitation of the obtained cellulose acetate propionate was washed with warm water. By changing the washing conditions at this time, the cellulose acetate propionate which changed the quantity of residual sulfuric acid root can be obtained. After washing, the mixture was stirred for 0.5 hour in an aqueous 0.005% by mass calcium hydroxide solution at 20 ° C, and further washed with water until the pH of the washing solution reached 7, followed by vacuum drying at 70 ° C.

^{According to 1} H-NMR and GPC measurements, the cellulose acetate propionate obtained had an acetylation degree of 0.30, a propionylation degree of 2.63, and a polymerization degree of 320. The content of sulfate root was measured by ASTM D-817-96.

Synthesis Example 2 Synthesis of Cellulose Acetate Butyrate

100 g of cellulose (hardwood pulp) and 135 g of acetic acid were placed in a 5 L detachable flask to which a reflux device as a reaction container was attached, and left to stand for 1 hour while heating in an oil bath adjusted to 60 ° C. Then, it stirred vigorously for 1 hour, heating in the oil bath adjusted to 60 degreeC. The cellulose subjected to such pretreatment swelled and pulverized to exhibit fluff shape. The reaction vessel was placed in a 5 ° C ice water bath for 1 hour to sufficiently cool the cellulose.

Separately, a mixture of 1080 g of butyric anhydride and 10.0 g of sulfuric acid was prepared as an acylating agent, and after cooling to -20 ° C, it was added to the reaction vessel containing the pretreated cellulose at once. After 30 minutes had elapsed, the snow temperature was raised to 20 ° C and allowed to react for 5 hours. The reaction vessel was cooled in an ice bath of 5 ° C., and 2400 g of 12.5 mass% hydrous acetic acid cooled to about 5 ° C. was added over 1 hour. The internal temperature was raised to 30 ° C. and stirred for 1 hour. Next, 100 g of a 50 mass% aqueous solution of magnesium acetate tetrahydrate was added to the reaction vessel, followed by stirring for 30 minutes. 1000 g of acetic acid and 2500 g of 50 mass% hydrous acetic acid were gradually added to precipitate cellulose acetate butyrate. The obtained cellulose acetate butyrate was washed with warm water. By changing the washing conditions at this time, the cellulose acetate butyrate which changed the quantity of residual sulfuric acid root can be obtained. After washing, the mixture was stirred for 0.5 hour in an aqueous 0.005% by mass calcium hydroxide solution, washed again with water until the pH of the washing solution reached 7, and then dried at 70 ° C. The obtained cellulose acetate butyrate had an acetylation degree of 0.84, a butyrylation degree of 2.12, and a polymerization degree of 268.

<< Examples 101-112, Comparative Examples 101-103 >> Production of a transparent polymer film

(Preparation of Polymer Solution)

1) cellulose acylate

In each example and the comparative example, the cellulose acylate which has a substitution degree of Table 1 was synthesize | combined with reference to the said synthesis example. Each cellulose acylate was heated to 120 ° C, dried, and the water content was 0.5% by mass or less, and then 15 parts by mass were used.

2) solvent

In each example and comparative example, a mixed solvent of dichloromethane / methanol / butanol (83/15/2 parts by mass) was used. In addition, the moisture content of the solvent was all 0.2 mass% or less.

3) additive

In each Example and the comparative example, the side described in Table 1 was selected and used among the additives A and B of the following composition.

ㆍ Additive A:

Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.08 parts by mass)

ㆍ Additive B:

Triphenylphosphate (1.2 parts by mass)

Biphenyldiphenylphosphate (0.6 parts by mass)

Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.08 parts by mass)

4) Swelling, Melting

In each Example and the comparative example, the said cellulose acylate was added gradually, stirring and disperse | distributing to the 400 liter stainless steel dissolution tank which has a stirring blade and the cooling water circulates, stirring and disperse | distributing. After the addition was completed, the mixture was stirred at room temperature for 2 hours, swollen for 3 hours, and then stirred again to obtain a cellulose acylate solution.

In addition, for stirring, anchors are provided on an eccentric stirring shaft and a central shaft of a dissolver type, which are stirred at a circumferential speed of 15 m / sec (shear stress 5 × 10 ⁴ kgf / m / sec ² [4.9 × 10 ⁵ N / m / sec ² ]). A stirring shaft was stirred with a blade at a circumferential speed of 1 m / sec (shear stress 1 × 10 ⁴ kgf / m / sec ² [9.8 × 10 ⁴ N / m / sec ² ]). Swelling was performed by stopping a high speed stirring shaft and making the circumferential speed of the stirring shaft which has an anchor blade into 0.5 m / sec.

The swollen solution was heated from the tank to 50 ° C in a jacketed pipe and further heated to 90 ° C under a pressure of 2 MPa to completely dissolve. The heating time was 15 minutes. At this time, the filter, housing | casing, and piping which were exposed to high temperature used what was made of Hastelloy alloy, and was excellent in corrosion resistance, and the thing which has a jacket which distribute | circulates the fruit for thermal heating was used.

Next, temperature was lowered to 36 degreeC and the cellulose acylate solution was obtained.

5) Filtration

The obtained cellulose acylate solution was filtered with a filter paper (# 63, manufactured by Toyo Filter Paper Co., Ltd.) having an absolute filtration accuracy of 10 µm, and again filtered with a metal sintered filter (FH025, manufactured by Paul Co., Ltd.) having an absolute filtration accuracy of 2.5 µm. Got.

(Manufacture of Film)

The said cellulose acylate solution was heated to 30 degreeC, and it casted on the mirror-surface stainless steel support body of 60 m of band lengths set through 15 degreeC (it describes in Unexamined-Japanese-Patent No. 11-314233) and set to 15 degreeC. The casting speed was 50 m / min and the coating width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. And the cellulose acylate film which had been cast and rotated by 50 cm from the end part of a casting | flow_spread part was peeled from the band, and the drying air of 45 degreeC was blown. Next, it dried for 5 minutes at 110 degreeC, and 10 minutes at 140 degreeC again, and obtained the transparent film which is 80 micrometers in film thickness of a cellulose acylate.

(Heat treatment)

The obtained film was heat-treated using the apparatus which has a heating zone between two nip rolls. The aspect ratio (distance between nip rolls / base width) was adjusted to 3.3, and the heating zone was set to the temperature shown in Table 1, and after passing two nip rolls, the film was cooled to 25 ° C. at 1000 ° C./min. Moreover, extending | stretching of the film put the mark of a fixed space | interval in the direction orthogonal to the conveyance direction of a film, measured the space | interval before and after heat processing, and calculated | required by the following formula.

Stretching of film (%) = 100 × (interval of mark after heat treatment-gap of mark before heat treatment) / spacing of mark before heat treatment

Moreover, the shrinkage rate of the width direction calculated | required by the following formula in the heat processing process of the film of Examples 101-112 and Comparative Examples 101-103 was in 5 to 50% of range.

Shrinkage (%) in the width direction of the film = 100 x (total width before heat treatment-full width after heat treatment) / total width before heat treatment

(Evaluation of Transparent Polymer Film)

Each obtained transparent polymer film was evaluated. The results are shown in Table 1 below.

In addition, in Examples 101-112, the slow axis of Re of the film was observed in the width direction of the film, and in the comparative example 101, the slow axis of Re of the film was observed in the conveyance direction of the film. In addition, the variation of Re and Rth (deviation of the measured value of 5 points) evaluated based on the above-mentioned method is Re within ± 1 nm and Rth within ± 2 nm in all the samples. Was less than 1 °. Moreover, the water vapor transmission rate of the film thickness of 80 micrometers of the films of Examples 101-112 and Comparative Examples 101-103 is all in the range of 400-1200 g / (m <2> * day), and all the water vapor transmission rates before heat processing of these films are 250-1000g. It was in the range of / (m 2 · day).

As shown in Table 1, Tc≤T <Tm ₀ Re of the transparent polymer film obtained can be enlarged by heat-processing at the temperature T which satisfy | fills. In addition, by heat treatment at a temperature T satisfying the Tc≤T <Tm _0, │Rth│ / Re can be obtained is relatively small transparent polymer film. In particular, it is possible to easily obtain a transparent polymer film that satisfies Rth / Re <0.5, which could not be produced without a complicated process. Further, Tc≤T <a transparent polymer film obtained by heat treatment at a temperature T satisfying the Tm is _0, it was confirmed that a small humidity dependency and variation of retardation.

Examples 115 to 118 Preparation of Transparent Polymer Films

Using the additive A of the composition described in Examples 101-112, the transparent polymer film was manufactured by the method similar to Examples 101-112 on the cellulose acetate which has a substitution degree shown in Table 2, and heat processing conditions.

The evaluation result of each obtained transparent polymer film was also described in Table 2.

As shown in Table 2, by heat treatment at a temperature T satisfying the Tc≤T <Tm _0, it is possible to increase the Re of the transparent polymer film is obtained. At this time, it was confirmed that the expression of retardation was improved by increasing the degree of substitution of cellulose acetate.

<< Examples 120-140, Comparative Example 121 >> Production of a transparent polymer film

(Preparation of Polymer Solution)

1) cellulose acylate

In Examples 120-138 and Comparative Example 121, the ones shown in Table 3 were selected from the following cellulose acylates A and B and used. Each cellulose acylate was heated to 120 ° C, dried, and the water content was 0.5% by mass or less, and then 15 parts by mass were used.

Cellulose acylate A:

A powder of cellulose acetate having a degree of substitution of 2.85 was used. Viscosity-average degree of polymerization of cellulose acylate A is 300, 6-position acetyl group substitution degree is 0.89, acetone extracted content is 7 mass%, mass average molecular weight / number average molecular weight ratio is 2.3, water content is 0.2 mass%, 6 mass% dichloro The viscosity in the methane solution is 305 mPa · s, the amount of residual acetic acid is 0.1 mass% or less, the Ca content is 65 ppm, the Mg content is 26 ppm, the iron content is 0.8 ppm, the sulfate content is 18 ppm, the yellow index is 1.9, and the free acetic acid amount is 47 ppm. It was. The average particle diameter of the powder was 1.5 mm, and the standard deviation was 0.5 mm.

Cellulose acylate B:

A powder of cellulose acetate having a degree of substitution of 2.95 was used. Viscosity-average degree of polymerization of cellulose acylate B was acetyl group substitution degree of 300, 6 position was 0.94 (moisture permeability at 40 ° C. and relative humidity of 90% was 400-1200 g / (m 2 · day) in terms of film thickness of 80 μm. Within the range).

2) solvent

In each Example and the comparative example, the side described in Table 3 was selected and used among the following solvents A and B. In addition, the moisture content of the solvent was all 0.2 mass% or less.

Solvent A

A mixed solvent of dichloromethane / methanol / butanol (83/15/2 parts by mass) was used.

Solvent B

A mixed solvent of dichloromethane / methanol (83/17 parts by mass) was used.

Solvent C

A mixed solvent of dichloromethane / methanol (92/8 mass part) was used.

Solvent D

A mixed solvent of dichloromethane / methanol (97/3 parts by mass) was used.

Solvent E

A mixed solvent of dichloromethane (100 parts by mass) was used.

3) additive

The additive shown in Table 3 was selected and used among additives A and B of the composition described in Examples 101-112.

4) melting

In each Example and the comparative example, the one described in Table 3 was selected from the following dissolution process A and B, and was used.

ㆍ Dissolution Process A

The said cellulose acylate was added gradually, stirring and disperse | distributing the said solvent and an additive to the 400 liter stainless steel dissolution tank which has a stirring blade and circulates the cooling water around. After the addition was completed, the mixture was stirred at room temperature for 2 hours, swollen for 3 hours, and then stirred again to obtain a cellulose acylate solution.

In addition, for stirring, the eccentric stirring shaft and the central shaft of the dissolver type which are stirred at a circumferential speed of 15 m / sec (shear stress 5 × 10 ⁴ kgf / m / sec ² [4.9 × 10 ⁵ N / m / sec ² ]) are The stirring shaft which used the anchor blade and stirred at circumferential speed 1m / sec (shear stress 1 * 10 <^4> kgf / m / sec <^2> (9.8 * 10 <^4> N / m / sec <^2> )) was used. Swelling was performed by stopping a high speed stirring shaft and making the circumferential speed of the stirring shaft which has an anchor blade into 0.5 m / sec.

The swollen solution was heated from the tank to 50 ° C in a jacketed pipe and further heated to 90 ° C under a pressure of 2 MPa to completely dissolve. The heating time was 15 minutes. At this time, the filter, the housing, and the piping exposed to high temperature were made of Hastelloy alloy, which had excellent corrosion resistance, and used to have a jacket for circulating the fruit for thermal heating.

Next, temperature was lowered to 36 degreeC and the cellulose acylate solution was obtained.

ㆍ melting process B

The said cellulose acylate was added gradually, stirring and disperse | distributing the said solvent and an additive to the 400 liter stainless steel dissolution tank which has a stirring blade and circulates the cooling water around. After the addition was completed, the mixture was stirred at room temperature for 2 hours, swollen for 3 hours, and then stirred again to obtain a cellulose acylate solution.

In addition, for stirring, the eccentric stirring shaft and the central shaft of the dissolver type which are stirred at a circumferential speed of 15 m / sec (shear stress 5 × 10 ⁴ kgf / m / sec ² [4.9 × 10 ⁵ N / m / sec ² ]) are The stirring shaft which used the anchor blade and stirred at circumferential speed 1m / sec (shear stress 1 * 10 <^4> kgf / m / sec <^2> (9.8 * 10 <^4> N / m / sec <^2> )) was used. Swelling was performed by stopping a high speed stirring shaft and making the circumferential speed of the stirring shaft which has an anchor blade into 0.5 m / sec.

The swollen solution was fed from a tank to a screw pump warmed to the shaft center at 30 ° C., cooled from the screw outer periphery, and passed through a cooling section at −70 ° C. for 3 minutes. Cooling was carried out using a -75 deg. C refrigerant cooled in a freezer. The solution obtained by cooling was heated to 30 degreeC by the screw pump at the liquid feed column, and was transferred to the stainless steel container.

Next, the temperature was lowered to 30 ° C and stirred at 30 ° C for 2 hours to obtain a cellulose acylate solution.

5) Filtration

The obtained cellulose acylate solution was filtered with a filter paper (# 63, manufactured by Toyo Filter Paper Co., Ltd.) having an absolute filtration accuracy of 10 µm, and again filtered with a metal sintered filter (FH025, manufactured by Paul Co., Ltd.) having an absolute filtration accuracy of 2.5 µm. Got.

(Manufacture of Film)

In each Example and the comparative example, the one described in Table 3 was selected from the following film forming processes A and B, and was used.

ㆍ Manufacturing process A

The said cellulose acylate solution was heated to 30 degreeC, and it casted on the mirror-surface stainless steel support body of 60 m of band lengths set through 15 degreeC (it describes in Unexamined-Japanese-Patent No. 11-314233) and set to 15 degreeC. The casting speed was 50 m / min and the coating width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. And the cellulose acylate film which had been cast and rotated by 50 cm from the end part of a casting | flow_spread part was peeled from the band, and the drying air of 45 degreeC was blown. Next, it dried for 5 minutes at 110 degreeC, and 10 minutes at 140 degreeC, and obtained the transparent film which is 80 micrometers in film thickness of cellulose acylate.

ㆍ Filmmaking Process B

The polymer solution was warmed to 30 ° C. and cast through a flexible base to cast on a mirror stainless steel support, a drum of 3 m in diameter. The temperature of the support was set to -5 ° C, the casting speed was 100 m / min, and the coating width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. Then, 50 cm from the end of the flexible part, the cellulose acylate film that had been flexibly rotated was peeled from the drum, and both ends were clipped with a pin tenter. The cellulose acylate film supported by the pin tenter was returned to the drying zone. In the first drying, a drying air at 45 ° C. was blown. Next, it dried for 5 minutes at 110 degreeC, and 10 minutes at 140 degreeC, and obtained the transparent film which is 80 micrometers in film thickness of cellulose acylate.

(Heat treatment)

The obtained film was heat-treated using the apparatus which has a heating zone between two nip rolls. The aspect ratio (distance between nip rolls / base width) was adjusted to 3.3, the base temperature before entering the heating zone was 25 ° C, and the heating zone was the temperature shown in Table 3. The temperature increase rate of the film at this time was adjusted to the value of Table 3. In the example where the temperature increase rate is less than 1,000 ° C / min, the temperature increase rate was adjusted by adjusting the amount of hot air, and in the example where the temperature increase rate was 1,000 ° C / min or more, the temperature increase rate was adjusted.

Next, the film was cooled to the cooling temperature shown in Table 3 at the rate shown in Table 3, and then passed through the nip roll. At this time, the dehumidification wind cooled for cooling was used, and the adjustment of the cooling rate was performed by adjusting the air volume of the cooling wind. In addition, the heat processing temperature, the temperature increase rate, the cooling temperature, and the cooling rate of the film were calculated | required from the data obtained with the thermocouple arrange | positioned on the film film surface. That is, the temperature increase rate was determined by taking the difference between the temperature at the heating zone inlet and the temperature at the heating zone outlet, and dividing by the time required to move the two points. Similarly, the cooling rate was calculated by taking the difference between the temperature at the cooling zone inlet and the temperature at the cooling zone outlet and dividing by the time required to move the two points.

Moreover, extending | stretching of the film before and behind heat processing was measured. The shrinkage rate in the width direction in the heat treatment step of the films of Examples 120 to 138 and Comparative Example 121 was in the range of 5 to 60% (the upper limit was set larger than Examples 101 to 112).

In addition, in Table 3, tag A is a commercially available cellulose acylate film (Fujitaek TD80UL; Fujifilm Co., Ltd. product), and tag B is a commercially available cellulose acylate film (Fujitaek T80UZ; Fujifilm Co., Ltd. product). to be. In Example 139, Tag B and Example 140 were used, respectively, and heat treatment and cooling were performed under the conditions shown in Table 3.

(Evaluation of the manufactured cellulose acylate film)

Table 3 shows the results of measuring the maximum values of Re, Rth, | Rth | / Re, and humidity curl of the transparent cellulose acylate film obtained in each Example and Comparative Example. In Examples 120-127 and 129-139, the slow axis of Re of the film was observed in the width direction of the film, and in Example 128, the slow axis of Re of the film was observed in the conveyance direction of the film. In addition, the variation of Re and Rth (deviation of the measured value of 5 points) evaluated based on the above-mentioned method is Re within ± 1 nm and Rth within ± 2 nm in all the samples. Was less than 1 °. Moreover, the water vapor transmission rate of the film thickness of 80 micrometers of the films of Examples 120-140 and the comparative example 121 is all in the range of 300-1000 g / (m <2> * day), and all the water vapor transmission rates before heat processing of these films are also 300-1000 g / ( M 2 · day).

As shown in Table 3, by heat treatment at a temperature T satisfying the Tc≤T <Tm _0, it is possible to increase the Re of the transparent polymer film is obtained. In addition, by heat treatment at a temperature T satisfying the Tc≤T <Tm _0, │Rth│ / Re can be obtained is relatively small transparent polymer film. In particular, it is possible to easily obtain a transparent polymer film that satisfies Rth / Re <0.5, which could not be produced without a complicated process. Moreover, it was confirmed that the retardation of the transparent polymer film obtained can further be improved by suppressing the cooling rate after heat processing, and the humidity curl of a film can be suppressed. In addition, as in Examples 120 to 123, the expression region of Re or Rth was expanded by increasing the alcohol content in the solvent. In Comparative Example 121, the film was melted and cut during conveyance.

<< Examples 141-154, Comparative Examples 141, 142 >> Production of a transparent polymer film

(Preparation of Polymer Solution)

1) cellulose acylate

Of the cellulose acylates A and B described in Examples 120 to 140, one described in Table 4 was selected and used. Each cellulose acylate was heated to 120 ° C, dried, and the water content was 0.5% by mass or less, and then 15 parts by mass were used.

2) solvent

In each example and comparative example, a mixed solvent of dichloromethane / methanol / butanol (83/15/2 parts by mass) was used. In addition, the moisture content of the solvent was all 0.2 mass% or less.

3) additive

In each example and the comparative example, silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.08 mass part) were used.

4) melting

Of the dissolution steps A and B described in Examples 120 to 140, one described in Table 4 was selected and used.

5) Filtration

The obtained cellulose acylate solution was filtered with a filter paper (# 63, manufactured by Toyo Filter Paper Co., Ltd.) having an absolute filtration accuracy of 10 µm, and again filtered with a metal sintered filter (FH025, manufactured by Paul Co., Ltd.) having an absolute filtration accuracy of 2.5 µm. Got.

(Manufacture of Film)

The film | membrane shown in Table 4 was selected and used among the film forming processes A and B described in Examples 120-140. The residual solvent amount was 0.5 mass%.

(Preliminary stretching)

In each Example and Comparative Example, it selected from the following preliminary stretching process A or B, and shows in Table 4.

Moreover, the preliminary draw ratio of the film put the mark of a fixed space | interval in the direction orthogonal to the conveyance direction of a film, measured the space | interval before and after heat processing, and calculated | required by the following formula.

Preliminary draw ratio (%) of film = 100 x (interval of mark after heat treatment-gap of mark before heat treatment) / spacing of mark before heat treatment

ㆍ Pre-stretching Process A

The cellulose acylate film formed into a film by the said film forming process A or B was extended | stretched using the apparatus which has a heating zone between two nip rolls. The draw ratio was controlled by adjusting the peripheral speed of the nip roll. The aspect ratio (distance between nip rolls / base width) was adjusted to 3.3, the base temperature before entering the heating zone was 25 ° C, and the heating zone was heated for 1 minute at the temperature shown in Table 4.

ㆍ Preliminary Stretching Process B

The obtained film was subjected to the transverse uniaxial stretching treatment using a roll stretching machine. The roll of the roll drawing machine used the induction heating jacket roll which mirrored the surface, and the temperature of each roll could be adjusted individually. The stretching zone was covered with a casing and the temperature shown in Table 4 was set. The roll in front of the stretching portion was set to be gradually heated to the stretching temperature shown in Table 4. The aspect ratio adjusted the distance between draws to be 3.3, and the draw speed was 10% / min with respect to the draw distance.

ㆍ Preliminary Stretching Process C

The obtained film was gripped with a tenter clip and stretched 20% in the width direction while passing the heating zone.

(Heat treatment)

In each Example and Comparative Example, it is selected from the following heat treatment step A or B and shown in Table 4. After the heat treatment the film was cooled to 25 ° C. at 500 ° C./min. Moreover, the draw ratio of the film put the mark of a fixed space | interval in the direction orthogonal to the extending | stretching direction of a film, measured the space | interval before and after heat processing, and confirmed that it was 20% calculated | required from the following formula.

Draw ratio of film (%) = 100 x (interval of mark after heat treatment-gap of mark before heat treatment) / spacing of mark before heat treatment

ㆍ Heat Treatment Process A

The obtained film was heat-treated using the apparatus which has a heating zone between two nip rolls. The shrinkage in the width direction was controlled by adjusting the temperature of the heating zone and the circumferential speed of the nip roll, and was performed while shrinking in the width direction (shrinkage: 30%). The aspect ratio (distance between nip rolls / base width) was adjusted to 3.3, the base temperature before entering the heating zone was 25 ° C, and the heating zone was heated for 1 minute at the temperature shown in Table 4.

ㆍ Heat Treatment Process B

It carried out similarly to the heat processing process A except having changed the heating time in the heat processing process A into 60 minutes.

(Evaluation of the manufactured cellulose acylate film)

Evaluation of each cellulose acylate film obtained by each Example and the comparative example was performed. The results are shown in Table 4 below.

The variation of Re and Rth of each sample taken in the same manner as the above retardation measurement (variation of 5 measured values) is within ± 1 nm and Rth is ± 2 in all samples except Example 152. It was within nm and fluctuated in the slow axis direction was less than 1 degree. Moreover, the in-plane slow-axis direction of all the Examples was facing the direction of 90 degrees with respect to the conveyance direction of a film. Moreover, the water vapor transmission rate of the film thickness of 80 micrometers of the films of Examples 141-154 and Comparative Examples 141, 142 are all in the range of 400-1200 g / (m <2> * day), and all the water vapor transmission rates before heat processing of these films are 250-1000 g. It was in the range of / (m 2 · day). In addition, the shrinkage rate in the width direction in the heat treatment step of these films was in the range of 5 to 50%.

As it is shown in Table 4, by heat treatment at a temperature T satisfying the Tc≤T <Tm _0, has the expression of the large retardation, the │Rth│ / Re to obtain a relatively small transparent polymer film. In particular, it is possible to easily obtain a transparent polymer film that satisfies Rth / Re <0.5, which could not be produced without a complicated process. Moreover, retardation of the transparent polymer film obtained can be improved further by performing preliminary stretching. In particular, a transparent polymer film having a larger Re and a smaller R '/ Re can be produced. Under the present circumstances, it turns out that it is preferable that the direction of preliminary stretching and the extending | stretching direction at the time of heat processing correspond in terms of the retardation value raise. In Comparative Example 141, the film was whitened, and in Comparative Example 142, the film was melted and cut during conveyance.

[Examples 161 to 172]

(Film manufacturing)

Of the following films A to C, those listed in Table 5 were selected and used.

Film A:

The film was manufactured in accordance with Example 12 of Unexamined-Japanese-Patent No. 2005-104148, and it was set as film A.

Film B:

Commercially available Fuji Tack (TD80UF; manufactured by Fuji Film Co., Ltd.) was used as it is.

Film C:

Commercially available Fuji Tack (T80UZ: manufactured by Fuji Film Co., Ltd.) was used as it is.

(Heat treatment)

The obtained film was heat-treated using the apparatus which has a heating zone between two nip rolls. The aspect ratio (distance between the nip rolls / base width) was adjusted to 3.3, and the heating zone was set to the temperature shown in Table 5, and after passing two nip rolls, the film was allowed to pass to the temperature shown in Table 5 at 500 ° C / min. Cooled. The shrinkage rate in the width direction in the heat treatment step of the films of Examples 161 to 172 was in the range of 5 to 50%.

(Extension)

Subsequently, after both ends of the film after heat processing were gripped with a tenter clip, it extended | stretched in the direction orthogonal to a conveyance direction in the inside of a heating zone. The heating zone was taken as the temperature of Table 5.

(Evaluation of Transparent Polymer Film)

Each obtained transparent polymer film was evaluated. The results are shown in Table 5 below. The slow axis of Re of the film after extending | stretching was observed in the direction orthogonal to the conveyance direction of a film in all. Moreover, Re (the deviation of the measured value of 5 points | pieces) of Re and Rth evaluated based on the method mentioned above was Re within ± 1 nm and Rth within ± 2 nm in all the samples. Moreover, the water vapor transmission rate of the film thickness of 80 micrometers of the films of Examples 161-172 is all in the range of 400-1200 g / (m <2> * day), and all the water vapor transmission rates before heat processing of these films are 250-1000 g / (m <2> * day). Was in the range of.

As shown in Table 5, by heat-treating at the temperature T which satisfy | fills Tc <= T <Tm <_0> , the transparent polymer film with large retardation and comparatively small | Rth | Re can be obtained. Moreover, Re and Rth can be finely adjusted by extending | stretching after heat processing.

Examples 181 to 192 Preparation of Transparent Polymer Films

(Preparation of Polymer Solution)

1) polymer

The cellulose acylate A described in Examples 120-140 was heated to 120 ° C and dried, and the water content was 0.5 mass% or less, and then 20 parts by mass were used.

2) solvent

In each example, a mixed solvent of dichloromethane / methanol / butanol (83/15/2 parts by mass) was used. In addition, the moisture content of the solvent was all 0.2 mass% or less.

3) additive

In each Example, any one of the addition compositions A-D of the following composition was used according to Table 6 below.

Additive Composition A:

Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.08 parts by mass)

Additive Composition B:

Triphenylphosphate (1.6 parts by mass)

Biphenyl Diphenyl Phosphate (0.8 part by mass)

Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.08 parts by mass)

Additive Composition C:

Triphenylphosphate (1.6 parts by mass)

Biphenyl Diphenyl Phosphate (0.8 part by mass)

Retardation synergist of the following structure (0.6 parts by mass)

[Formula 1]

Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.08 parts by mass)

Additive Composition D:

Triphenylphosphate (1.6 parts by mass)

Biphenyl Diphenyl Phosphate (0.8 part by mass)

Retardation synergist used in the additive composition C (0.3 parts by mass)

Silicon dioxide fine particles (particle size 20 nm, Mohs hardness about 7) (0.08 parts by mass)

4) Swelling, Melting

In each Example, the said polymer was added gradually, stirring and disperse | distributing the said solvent and an additive to the 400 liter stainless steel dissolution tank which has a stirring blade and circulates the outer periphery of cooling water. After the addition was completed, the mixture was stirred at room temperature for 2 hours, swollen for 3 hours, and then stirred again to obtain a polymer solution.

In addition, for stirring, anchors are provided on an eccentric stirring shaft and a central shaft of a dissolver type, which are stirred at a circumferential speed of 15 m / sec (shear stress 5 × 10 ⁴ kgf / m / sec ² [4.9 × 10 ⁵ N / m / sec ² ]). The stirring shaft which used the blade and stirred at circumferential speed 1m / sec (shear stress 1 * 10 <^4> kgf / m / sec <^2> (9.8 * 10 <^4> N / m / sec <^2> )) was used. Swelling was performed by stopping a high speed stirring shaft and making the circumferential speed of the stirring shaft which has an anchor blade into 0.5 m / sec.

The swollen solution was heated from the tank to 50 ° C in a jacketed pipe and further heated to 90 ° C under a pressure of 2 MPa to completely dissolve. The heating time was 15 minutes. At this time, the filter, housing | casing, and piping which were exposed to high temperature used what was made of Hastelloy alloy, and was excellent in corrosion resistance, and the thing which has a jacket which distribute | circulates the fruit for thermal heating was used. Next, the temperature was lowered to 36 ° C to obtain a polymer solution.

5) Filtration

The obtained polymer solution was filtrated with a filter paper (# 63, manufactured by Toyo Filter Paper Co., Ltd.) having an absolute filtration accuracy of 10 µm, and further filtered through a metal sintered filter (FH025, manufactured by Paul Co., Ltd.) having an absolute filtration accuracy of 2.5 µm. .

(Manufacture of Film)

In each Example and the comparative example, the one described in Table 6 was selected from the following film forming processes A and B, and was used.

ㆍ Manufacturing process A

The polymer solution was heated to 30 ° C, and cast on a mirror-shaped stainless steel support having a band length of 60 m which was set at 15 ° C through a casting method (described in JP-A-11-314233). The casting speed was 50 m / min and the coating width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. And 50 cm from the end part of a casting | flow_spread part, the polymer film which was cast and rotated was peeled off from a band, and 45 degreeC dry wind was blown. Next, it dried for 5 minutes at 110 degreeC, and 10 minutes at 140 degreeC, and obtained the transparent film of a cellulose acylate.

ㆍ Filmmaking Process B

The polymer solution was warmed to 30 ° C. and cast through a flexible base to cast on a mirror stainless steel support, a drum of 3 m in diameter. The temperature of the support was set to -5 ° C, the casting speed was 100 m / min, and the coating width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. Then, 50 cm from the end of the flexible part, the cellulose acylate film that had been flexibly rotated was peeled from the drum, and both ends were clipped with a pin tenter. The cellulose acylate film held by the pin tenter was returned to the drying zone. In the first drying, a drying air at 45 ° C. was blown. Next, it dried for 5 minutes at 110 degreeC, and 10 minutes at 140 degreeC, and obtained the transparent film of a cellulose acylate.

(Heat treatment)

The obtained film was heat-treated using the apparatus which has a heating zone between two nip rolls. The aspect ratio (distance between the nip rolls / base width) is adjusted to 3.3, the heating zone is set to the temperature shown in Table 6, and after passing two nip rolls, the film is brought to 500 degrees C / min to the temperature shown in Table 6 Cooled. The shrinkage rate in the width direction in the heat treatment step of the films of Examples 181 to 192 was in a range of 5 to 50%.

(Extension)

Subsequently, after both ends of the film after heat processing were gripped with a tenter clip, it extended | stretched in the direction orthogonal to a conveyance direction in the inside of a heating zone. The heating zone was made into the temperature of Table 6.

(Evaluation of Transparent Polymer Film)

Each obtained transparent polymer film was evaluated. The results are shown in Table 6 below. In addition, Rth after cooling of Example 182 is evaluated inline.

The slow axis of Re of the film after extending | stretching was observed in the direction orthogonal to the conveyance direction of a film in all. Moreover, Re (the deviation of the measured value of 5 points | pieces) of Re and Rth evaluated based on the method mentioned above was Re within ± 1 nm and Rth within ± 2 nm in all the samples. Moreover, the water vapor transmission rate of the film thickness of 80 micrometers of the films of Examples 181-192 is all in the range of 400-1200 g / (m <2> * day), and all the water vapor transmission rates before heat processing of these films are 250-1000 g / (m <2> * day). Was in the range of.

As shown in Table 6, by heat treatment at a temperature T that satisfies Tc ≤ T <Tm ₀ , a transparent polymer film having a large retardation and a relatively low Rth / Re can be obtained. Moreover, Re and Rth can be finely adjusted by extending | stretching after heat processing.

Examples 201 to 212 and Comparative Examples 201 to 205

(Preparation of Polymer Solution)

1) cellulose acylate

Of the cellulose acylates A and B described in Examples 120 to 140, one described in Table 7 was selected and used. Each cellulose acylate was heated to 120 ° C and dried, and the water content was 0.5 mass% or less, and then 15 parts by mass were used.

2) solvent

Of the solvents A and B described in Examples 120 to 140, one described in Table 7 was selected and used. In addition, the moisture content of the solvent was all 0.2 mass% or less.

3) additive

Among the additives A and B described in Examples 101 to 112, the ones shown in Table 7 were selected and used.

4) melting

Of the dissolution steps A and B described in Examples 101 to 112, one described in Table 7 was selected and used.

5) Filtration

The obtained cellulose acylate solution was filtered with a filter paper (# 63, manufactured by Toyo Filter Paper Co., Ltd.) having an absolute filtration accuracy of 10 µm, and then filtered with a metal sintered filter (FH025, manufactured by Paul Co., Ltd.) having an absolute filtration accuracy of 2.5 µm. Got.

(Manufacture of Film)

In each Example and the comparative example, the one described in Table 7 was selected from the following film forming processes A and B, and was used.

ㆍ Manufacturing process A

The said cellulose acylate solution was heated to 30 degreeC, and it casted on the mirror surface stainless steel support body of 60 m of band lengths which passed surface casting (it describes in Unexamined-Japanese-Patent No. 11-314233), and set the surface temperature to 15 degreeC. The application width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. And after peeling the cellulose acylate dope which casted and rotated 50 cm before the end part of a casting | flow_spread part from a band, both ends were gripped with a tenter. The residual solvent amount of the cellulose acylate web immediately after the peeling, the peeling rate (peel roll draw) relative to the support rate, and the film surface temperature of the cellulose acylate web are shown in Table 7. The cellulose acylate web held by the tenter was blown with a drying air at 45 ° C. Next, after drying at 110 ° C for 5 minutes and at 140 ° C for 10 minutes, the both ends (each 5% of the total width) were trimmed immediately before winding, and then both ends had a thickness of 10 mm in width and 50 μm in height (knurling) ) Was wound up in a roll shape of 3000 m. The width | variety of the transparent film obtained in this way was 1.5 m in each level, and the film thickness was 80 micrometers.

ㆍ Filmmaking Process B

The polymer solution was warmed to 30 ° C. and cast through a flexible base to cast on a mirror stainless steel support, a drum of 3 m in diameter. The surface temperature of the support was set to -5 ° C, and the coating width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. And after peeling the cellulose acylate film which was cast and rotated 50 cm before the end part of a casting | flow_spread part from a drum, both ends were clipped with the pin tenter. The residual solvent amount of the cellulose acylate web immediately after the peeling, the peeling rate (peel roll draw) relative to the support rate, and the film surface temperature of the cellulose acylate web are shown in Table 7. The cellulose acylate web held in the pin tenter was returned to the drying zone. In the first drying, a drying air at 45 ° C. was blown. Next, it dried for 5 minutes at 110 degreeC, and 10 minutes at 140 degreeC, after trimming both ends (each 5% of the total width) just before winding-up, thickness-betting (knurling) of width 10mm and height 50micrometer on both ends. After carrying out, it wound up in the roll shape of 3000 m. The width | variety of the transparent film obtained in this way was 1.5 m in each level, and the film thickness was 80 micrometers.

(Heat treatment)

In each Example and the comparative example, it selected from the following heat processing processes A-C, and it showed in Table 7. After the heat treatment the film was cooled to 25 ° C. at 500 ° C./min.

Moreover, extending | stretching of the film put the mark of a fixed space | interval in the direction orthogonal to the conveyance direction of a film, measured the space | interval before and after heat processing, and calculated | required by the following formula.

Stretching of film (%) = 100 × (interval of mark after heat treatment-gap of mark before heat treatment) / spacing of mark before heat treatment

ㆍ Heat Treatment Process A

The obtained film was heat-treated by roll to roll using the apparatus which has a heating zone between two nip rolls. The shrinkage ratio in the width direction was controlled by adjusting the temperature of the heating zone and the peripheral speed of the nip roll. The aspect ratio (distance between nip rolls / base width) was adjusted to 3.3, the base temperature before entering the heating zone was 25 ° C, and the heating zone was heated for 1 minute at the temperature shown in Table 7.

ㆍ Heat Treatment Process B

While holding both ends of the obtained film with a tenter clip, it heat-processed by roll to roll using the apparatus which let a heating zone pass. The shrinkage rate in the width direction was controlled by adjusting the rail width. The base temperature before entering a heating zone was 25 degreeC, and the heating zone was heated at the temperature of Table 7 for 1 minute.

ㆍ Heat Treatment C

The heat treatment step B was carried out in the same manner as the heat treatment step B except that the heating time was changed to 60 minutes.

(Evaluation of the manufactured cellulose acylate film)

Evaluation of each cellulose acylate film obtained by each Example and the comparative example was performed. The results are shown in Table 7 below.

The variation of Re and Rth of each sample taken out in the same manner as the above retardation measurement (variation of 5 measured values) is within ± 1 nm and Rth within ± 2 nm for all samples. The fluctuation in the direction was less than 1 °. Moreover, the water vapor transmission rate of the film thickness of 80 micrometers of the films of Examples 201-212 and Comparative Examples 201-205 is all in the range of 400-1200 g / (m <2> * day), and all the water vapor transmission rates before heat processing of these films are 250-1000g. It was in the range of / (m 2 · day).

As shown in Table 7, by heat-treating at the temperature T which satisfy | fills Tc <= T <Tm <_0> , the transparent polymer film with large retardation and comparatively small | Rth | Re can be obtained. In particular, by raising Re, a transparent polymer film having | Rth | / Re <0.5 can be obtained by an easy method. Moreover, Re and Rth can be finely adjusted further by extending | stretching in the state whose residual solvent is 5 mass% or more in the film forming process of a transparent polymer film. In addition, in the comparative example 203, the film melt | dissolved and cut | disconnected during conveyance.

Examples 221 to 229 and Comparative Examples 221 to 225

(Preparation of Polymer Solution)

It prepared in the same manner as in Examples 201 to 212. However, as a solvent, a mixed solvent of dichloromethane / methanol / butanol (83/15/2 parts by mass) was used.

(Manufacture of Film)

Of the following film forming steps A to C, the ones shown in Table 8 were selected and used.

ㆍ Manufacturing process A

The polymer solution was warmed to 30 ° C. and cast through a flexible base to cast on a mirror stainless steel support, a drum of 3 m in diameter. The surface temperature of the support was set to -5 ° C, and the coating width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. And after peeling the cellulose acylate film which was cast and rotated 50 cm before the end part of a casting | flow_spread part from a drum, both ends were clipped with the pin tenter. The residual solvent amount of the cellulose acylate web immediately after the peeling, the peeling rate (peel roll draw) relative to the support rate, and the film surface temperature of the cellulose acylate web are shown in Table 8. The cellulose acylate web held in the pin tenter was returned to the drying zone. In the first drying, a drying air at 45 ° C. was blown. Next, it dried for 5 minutes at 110 degreeC, and 10 minutes at 140 degreeC, and obtained the transparent film with a film thickness of 80 micrometers of a cellulose acylate.

ㆍ Filmmaking Process B

The said cellulose acylate solution was heated to 30 degreeC, and it casted on the mirror surface stainless steel support body of 60 m of band lengths which passed surface casting (it describes in Unexamined-Japanese-Patent No. 11-314233), and set the surface temperature to 15 degreeC. The application width was 200 cm. The space temperature of the whole flexible part was set to 15 degreeC. And after peeling the cellulose acylate dope which casted and rotated 50 cm before the end part of a casting | flow_spread part from a band, both ends were gripped with a tenter. The residual solvent amount of the cellulose acylate web immediately after the peeling, the peeling rate (peel roll draw) relative to the support rate, and the film surface temperature of the cellulose acylate web are shown in Table 8. The cellulose acylate web held by the tenter was blown with a drying air at 45 ° C. Next, it dried for 5 minutes at 110 degreeC, and 10 minutes at 140 degreeC, and obtained the transparent film with a film thickness of 80 micrometers of a cellulose acylate.

ㆍ Filmmaking Process C

In film forming process A, it carried out similarly to film forming process A except having set the surface temperature of the support body to 0 degreeC, and the space temperature of the whole casting part to 45 degreeC.

(Heat treatment)

It carried out in the same manner as in Examples 201 to 212.

(Evaluation of the manufactured cellulose acylate film)

Evaluation of each cellulose acylate film obtained by each Example and the comparative example was performed. The results are shown in Table 8 below. The variation of Re and Rth of each sample taken out in the same manner as the above retardation measurement (variation of 5 measured values) is within ± 1 nm and Rth within ± 2 nm for all samples. The fluctuation in the direction was less than 1 °. Moreover, the water vapor transmission rate of the film thickness of 80 micrometers of the films of Examples 221-229 and Comparative Examples 221-225 is all in the range of 400-1200 g / (m <2> * day), and all the water vapor transmission rates before heat processing of these films are 250-1000 g. It was in the range of / (m 2 · day).

As shown in Table 8, by heat treatment at a temperature T satisfying the Tc≤T <Tm _0, the retardation large, │Rth│ / Re can be obtained is relatively small transparent polymer film. In particular, Re is raised and the transparent polymer film of | Rth | / Re <0.5 can be obtained by an easy method. Moreover, Re and Rth can be finely adjusted further by extending | stretching in the state which residual solvent is 5 mass% or more in the film forming process of a transparent polymer film. In Comparative Example 223, the film was melted and cut during conveyance.

Examples 251 to 255 Re-stretching of film

After holding both ends of the cellulose acylate film of Example 110 with a tenter clip, it extended | stretched in the direction orthogonal to a conveyance direction inside the heating zone (Example 251). The temperature of the heating zone was 160 degreeC, and it extended | stretched 20%. In addition, the draw ratio put the line of a fixed space | interval in the direction parallel to the conveyance direction of a film, measured the space | interval before and after extending | stretching, and calculated | required by the following formula.

Stretch ratio (%) = 100 × (interval of mark lines after stretching-interval of mark lines before stretching) / interval of mark lines before stretching

When Re and Rth of the obtained film were measured, it was Re = 123 nm and Rth = -2 nm. Moreover, the slow axis of Re of this film was observed in the width direction of the film.

About the cellulose acylate film of Example 130, it extended | stretched 25% by the same method, and it became Re = 170 nm and Rth = -1 nm (Example 252). Moreover, the slow axis of Re of this film was observed in the width direction of the film.

The cellulose acylate film of Example 142 was stretched 33% by the same method, and as a result, haze was 0.3%, Re was 210 nm, and Rth was -15 nm (Example 253). Moreover, the slow axis of Re of this film was observed in the width direction of the film.

About the cellulose acylate film of Example 208, when it extended | stretched 30% by the same method, it became haze = 0.2%, Re = 148 nm, and Rth = 0 nm (Example 254). Moreover, the slow axis of Re of this film was observed in the width direction of the film.

About the cellulose acylate film of Example 228, it extended | stretched 30% by the same method, and it turned into haze = 0.2%, Re = 216 nm, Rth = 42 nm (Example 255). Moreover, the slow axis of Re of this film was observed in the width direction of the film.

Comparative Examples 251 and 252 Preparation of Birefringent Films

The cellulose acylate film before the heat treatment of Example 101 was treated in accordance with Example 5 of JP-A-5-157911 to obtain a birefringent film (Comparative Example 251). The variation in the slow axis direction of this film was large at 8 °, and the variation in Re and Rth (the variation in the measured values at five points) was large at ± 13 nm and Rth at ± 21 nm.

Similarly, the birefringent film was obtained using the cellulose acylate film before the heat processing of Example 139 (comparative example 252). The fluctuation | variation range of the slow axis direction of this film was large at 8 degrees, and Re and Rth (variation of the measured value of 5 points) were Re as ± 25 nm, and Rth as large as ± 43 nm.

<< Examples 271-277 >> Production of laminated retardation film

Although the cellulose acylate film of this invention can be used as a retardation film as it is, in this case, the retardation film which controlled Rth / Re ratio was manufactured by attaching a film by roll-to-roll using an adhesive (Example 271).

Fujitack TD80UF (manufactured by Fujifilm Co., Ltd.) and Example 103 were attached by a roll-to-roll using a pressure-sensitive adhesive, and Re and Rth were measured by the above-described method, and Re = 117 nm and Rth = 0 nm. Moreover, the slow axis of Re of this retardation film was observed in the width direction of a film.

Fujitaek TD80UF (manufactured by Fujifilm Co., Ltd.) and two films of Example 127 were attached to each other using a pressure-sensitive adhesive with a roll-to-roll, and Re and Rth were measured by the method described above. Re = 240 nm and Rth = 0 nm (Example 272). Moreover, the slow axis of Re of this retardation film was observed in the width direction of a film.

Two sheets of Fujitaek T80UZ (manufactured by Fujifilm Co., Ltd.) and the film of Example 142 were attached to each other using a pressure-sensitive adhesive with a roll-to-roll, and Re and Rth were measured by the method described above. Re = 218 nm, Rth = -18 nm (Example 273). Moreover, the slow axis of Re of this retardation film was observed in the width direction of a film.

Two films of Example 166 were attached to each other by a roll-to-roll using a pressure-sensitive adhesive, and Re and Rth were measured by the above-described method, and Re = 252 nm and Rth = 65 nm (Example 274). Moreover, the slow axis of Re of this retardation film was observed in the width direction of a film.

Fujitaek T80UZ (manufactured by Fujifilm Co., Ltd.) and Example 188 were adhered by a roll-to-roll using a pressure-sensitive adhesive, and Re and Rth were measured by the above-described method, and Re = 150 nm and Rth = 0 nm ( Example 275). Moreover, the slow axis of Re of this retardation film was observed in the width direction of a film.

Fujitaek TD80UL (manufactured by Fujifilm Co., Ltd.) and Example 209 were attached to each other by a roll-to-roll using a pressure-sensitive adhesive, and Re and Rth were measured by the above-mentioned method, and Re = 166nm and Rth = -19nm. (Example 276). Moreover, the slow axis of Re of this retardation film was observed in the width direction of a film.

Fujitaek TD80UL (manufactured by Fujifilm Co., Ltd.) and the film of Example 255 were attached to each other by a roll-to-roll using a pressure-sensitive adhesive, and Re and Rth were measured by the method described above. Re = 213 nm and Rth = 86 nm (Example 277). Moreover, the slow axis of Re of this retardation film was observed in the width direction of a film.

<< Examples 301-431, Comparative Examples 301-307 >> Manufacturing and evaluation of a polarizing plate

1) Saponification of the film

After immersing the film A and the film B shown in Table 9 below in a 1.5 mol / L aqueous NaOH solution (saponification liquid) temperature-controlled at 55 ° C. for 2 minutes, the film was washed with water, and thereafter 0.05 mol / L sulfuric acid After soaking in aqueous solution for 30 seconds, it passed the water washing bath again. And the removal by air knife was repeated 3 times, after removing water, it was made to dry for 15 second in the 70 degreeC dry zone, and the saponified film was produced.

2) Preparation of Polarizing Film

According to Example 1 of Unexamined-Japanese-Patent No. 2001-141926, the peripheral speed difference was provided between two pairs of nip rolls, it extended | stretched in the longitudinal direction, and the polarizing film of 20 micrometers in thickness was prepared.

3) Attach

Thus, two pieces were selected from the polarizing film obtained and the said saponified film (it was set as film A and film B, respectively, and the combination in each Example and a comparative example is described in Table 9 below), and the film After placing a soap screen on the polarizing film side and interposing the said polarizing film between them, PVA (Kuraray Co., Ltd. product, PVA-117H) 3% aqueous solution is used as an adhesive agent, and it adheres so that a polarization axis and a film may orthogonally cross. It was.

In addition, in Table 9 below, "tack A" means Fuji-Taek TD80UF (Fuji Film Co., Ltd. product; water vapor transmission rate at 430 degreeC and 90% of relative humidity = 430 g / (m <2> * day) (film thickness of 80 micrometers)) "Polycarbonate" refers to the backlight C1400 (Teijin Kasei Co., Ltd .; water vapor transmission rate = 30 g / (m 2 · day) (film thickness of 80 μm equivalent) at 40 ° C and 90% relative humidity), "COP1" represents an aton film (film thickness of 80 micrometers, JSR Corporation make; water vapor transmission rate = 30 g / (m <2> * day) (film thickness of 80 micrometers conversion) in 40 degreeC and 90% of relative humidity)). In addition, "COP2" shows a zeonoa film (film thickness of 100 micrometers, Nippon Xeon make; water vapor transmission rate = 0g / (m <2> * day) in terms of film thickness of 80 micrometers in 40 degreeC and 90% of relative humidity).

In Comparative Example 304, the surface treatment of the film was changed to corona treatment and adhesion was performed.

4) Evaluation of Polarizer

(Initial polarization degree)

The polarization degree of the said polarizing plate was computed by the method mentioned above. The results are shown in Table 9 below.

(Polarization degree 1 over time)

The film A side of the said polarizing plate was affixed on the glass plate with an adhesive, it was left to stand on 60 degreeC and the conditions of 95% of relative humidity for 500 hours, and the polarization degree (polarization degree with time progress) after standing was computed by the method mentioned above. The results are shown in Table 9 below.

(Polarization degree 2 over time)

The film A side of the said polarizing plate was affixed on the glass plate with an adhesive, it was left to stand on 90 degreeC and the conditions of 0% of relative humidity for 500 hours, and the polarization degree (polarization degree with time progress) after standing was computed by the above-mentioned method. The results are shown in Table 9 below.

5) Mounting evaluation for IPS type liquid crystal display

As a result of mounting the polarizing plates of Examples 303 and 312 in place of the polarizing plates mounted on the IPS type liquid crystal display device (32V type Hi-vision LCD television monitor (W32-L7000), Hitachi, Ltd.), the viewing angle characteristics Improvements were made. This effect is observed even when the liquid crystal display is observed after being left for 500 hours in a low humidity condition (25 ° C. and 10% relative humidity), and after 500 hours in a high humidity condition (25 ° C. and a relative humidity 80%). Was also confirmed. On the other hand, when attaching the polarizing plates of Comparative Examples 305-307, the viewing angle characteristic was not improved or it was not enough even if it improved.

In the same manner, Example 327, Example 335, Example 346, Example 349, Example 350, Example 364, Example 366, Example 381, Example 385, Example 387, Example 409, Example As a result of mounting each polarizing plate of 413 instead of the polarizing plate attached to the IPS type | mold liquid crystal display device (32V type Hi-vision liquid crystal television monitor (W32-L7000), Hitachi Ltd. make), the viewing angle characteristic improved. The viewing angle characteristic improvement effect of the polarizing plates of Example 327 and Example 335 was better than the case where Example 337 was attached. Moreover, the viewing angle characteristic improvement effect of the polarizing plates of Example 346, Example 349, and Example 350 was better than the case where Example 341 was attached. Moreover, the viewing angle characteristic improvement effect of the polarizing plates of Example 409 and Example 413 was better than the case where Example 406 was attached.

Two sets of polarizing plates of Example 430 were prepared, and the liquid crystal display device which overlapped and mounted in order of "Example 310 / IPS type liquid crystal cell / Example 430" was manufactured so that the film A side might become a liquid crystal cell side, respectively. . At this time, the transmission axis of the upper and lower polarizing plates was orthogonal, and the transmission axis of the upper polarizing plate was parallel to the molecular long axis direction of the liquid crystal cell (that is, the slow axis of the optical compensation layer and the molecular long axis direction of the liquid crystal cell were orthogonal). The liquid crystal cell and the electrode and board | substrate used what was conventionally used as IPS as it is. Moreover, the orientation of a liquid crystal cell is horizontal orientation, the liquid crystal has positive dielectric anisotropy, and what was developed and marketed for IPS liquid crystal was used. The physical properties of the liquid crystal cell were Δn of the liquid crystal, 0.099, the cell gap of the liquid crystal layer: 3.0 µm, the pretilt angle: 5 °, and the rubbing direction: both the upper and lower substrates were 75 °. The liquid crystal display device thus produced was excellent in viewing angle characteristics.

According to this invention, the expression property of retardation can be adjusted by comparatively easy operation. In particular, in the conventional method, it is possible to easily produce a transparent polymer film of Rth / Re <0.5, which could not be produced without following a complicated method. Moreover, the transparent polymer film manufactured can be applied widely to optical uses, such as retardation film. Moreover, since the transparent polymer film of this invention has moderate moisture permeability, it can be made to adhere online with a polarizing film, and can provide the polarizing plate excellent in visibility with high productivity. In addition, a highly reliable liquid crystal display device can be provided. Therefore, the present invention has high industrial applicability.

Claims (27)

A method for producing a transparent polymer film, comprising the step of heat-treating the polymer film at a temperature T (unit; ° C.) that satisfies the conditions of the following formula (1). Equation (1): Tc≤T <Tm ₀ [Wherein Tc represents the crystallization temperature (unit; ° C.) of the polymer film before the heat treatment, and Tm ₀ represents the melting point (unit; ° C.) of the polymer film before the heat treatment.] The method of claim 1, Stretching simultaneously with the heat treatment, characterized in that the manufacturing method of the transparent polymer film. The method according to claim 1 or 2, It carries out, conveying the said heat processing, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method of claim 1, It carries out while conveying the said heat processing, and extends to this conveyance direction, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method according to any one of claims 1 to 4, A process for producing a transparent polymer film, characterized in that stretching at a temperature below Tc after the heat treatment. The method of claim 5, wherein It carries out while conveying the said heat processing, and extends in the direction orthogonal to the conveyance direction at the time of the said heat processing at the temperature below Tc after the said heat processing, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method according to any one of claims 1 to 6, A method for producing a transparent polymer film, wherein the polymer film before heat treatment is stretched before the heat treatment. The method of claim 7, wherein The said heat processing is performed, extending | stretching in the same direction as the extending | stretching before the said heat processing, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method according to any one of claims 1 to 8, At the time of the heat treatment, the polymer film shrinks by 5 to 80%. The method of claim 9, The polymer film before the said heat processing is conveyed and produced, and the shrinkage at the time of the said heat processing is performed in the direction orthogonal to this conveyance direction, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method according to any one of claims 1 to 10, Method for producing a transparent polymer film, characterized in that for cooling the film at 100 to 1,000,000 ℃ / min after the heat treatment. The method according to any one of claims 1 to 11, The said polymer is cellulose acylate, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method of claim 12, Said cellulose acylate satisfy | fills following formula (3), The manufacturing method of the transparent polymer film characterized by the above-mentioned. Equation (3): 2.70 <SA + SB≤3.00 [In formula, SA shows the substitution degree of the acetyl group substituted by the hydroxyl group of a cellulose, and SB shows the substitution degree of the C3 or more acyl group substituted by the hydroxyl group of a cellulose. " The method according to claim 12 or 13, The said cellulose acylate satisfy | fills following formula (4), The manufacturing method of the transparent polymer film characterized by the above-mentioned. Equation (4): 0 <SB≤3.0 [In formula, SB shows the substitution degree of the C3 or more acyl group substituted by the hydroxyl group of a cellulose.] The method according to any one of claims 1 to 14, The polymer film before the said heat processing is conveyed and produced, and it is 0.1% or more and less than 15% extending | stretching in the state which is 5 to 1000% of residual solvent amount in this conveyance direction, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method according to any one of claims 1 to 14, The polymer film before the said heat processing is conveyed and produced, 15-300% of the manufacturing method of the transparent polymer film is extended | stretched in the state which is 5 to 1000% of residual solvent amount in this conveyance direction. The method according to any one of claims 1 to 16, The water vapor transmission rate of 80 micrometers conversion of the polymer film before the said heat processing is 100 g / (m <2> * day) or more, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method according to any one of claims 1 to 17, The polymer film before the said heat processing contains the addition composition which raises Rth of the polymer film before this heat processing, The manufacturing method of the transparent polymer film characterized by the above-mentioned. The method according to any one of claims 1 to 18, The transparent polymer film which satisfy | fills following formula (2) is manufactured, The manufacturing method of the transparent polymer film characterized by the above-mentioned. Equation (2): Rth / Re <0.5 [Wherein Re represents a retardation value (unit; nm) in the in-plane direction, and Rth represents a retardation value (unit; nm) in the film thickness direction.] The transparent polymer film is heat-treated at a temperature T (unit; ° C.) that satisfies the conditions of the following formula (1), wherein the expression of retardation of the transparent polymer film is adjusted. Equation (1): Tc≤T <Tm ₀ [Wherein Tc represents the crystallization temperature (unit; ° C.) of the polymer film before the heat treatment, and Tm ₀ represents the melting point (unit; ° C.) of the polymer film before the heat treatment.] A process for producing a transparent polymer film satisfying the following formula (2), comprising the step of heat-treating the transparent polymer film at a temperature T (unit; ° C.) satisfying the conditions of the following formula (1). Equation (1): Tc≤T <Tm ₀ [Wherein Tc represents the crystallization temperature (unit; ° C.) of the polymer film before the heat treatment, and Tm ₀ represents the melting point (unit; ° C.) of the polymer film before the heat treatment.] Equation (2): Rth / Re <0.5 [Wherein Re represents a retardation value (unit; nm) in the in-plane direction, and Rth represents a retardation value (unit; nm) in the film thickness direction.] The transparent polymer film manufactured by the manufacturing method in any one of Claims 1-21. The method of claim 22, Transparent polymer film, wherein the polymer is cellulose acylate. Retardation film which has one or more sheets of transparent polymer film of Claim 22 or 23. It has one or more sheets of the transparent polymer film of Claim 22 or 23, The polarizing plate characterized by the above-mentioned. The method of claim 25, The transparent polymer film is directly attached to the polarizing film, characterized in that the polarizing plate. The liquid crystal display device which has one or more sheets of the transparent polymer film of Claim 22 or 23, the retardation film of Claim 24, or the polarizing plate of Claim 25 or 26.