JP2006103145A - Polymer film, solution film-forming method and tenter type drier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a film restrained from the axis deviation of the longitudinal direction. <P>SOLUTION: TAC and additives are dissolved in a solvent to obtain a dope. A cast film is formed by casting the dope on a cast belt from a cast die. After the cast film becomes one having a self-supporting nature, it is removed from the cast belt as a wet film 46. The wet film 46 is conveyed to a tenter type drier 60. The tenter type drier 60 has tenter chains 82, 83 having a length of 60 m. The tenter chains 82, 83 are equipped with a great number of tenter clips 80, 81 to grip the film. The tenter chains 82, 83 move while being wound around and engaged with sprockets 84-87. The displacements of the driven sprockets 86, 87 are detected with sensors 91, 92. Shift mechanisms 93, 94 adjust the positions of the driven sprockets 86, 87 so that the difference of the lengths of the tenter chains 82, 83 may be 4 mm or smaller. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polymer film, a solution casting method for producing the polymer film, and a tenter dryer used in the solution casting method.

  Polymers are used in a variety of applications. For example, cellulose acylate (hereinafter referred to as TAC) is used as a film and used as a base film of a photographic material or as a polarizing plate protective film used in a liquid crystal display (LCD). As a method for producing a film, there are known a melt film-forming method in which a polymer is heated to form a film, and a solution film-forming method in which a dope containing a solvent and a polymer is prepared to form a film. A film obtained by the solution casting method is excellent in optical isotropy and is preferably used as an optical film (see, for example, Non-Patent Document 1).

  Liquid crystal display devices are widely used in applications such as monitors for personal computers, portable devices, and televisions because of their various advantages, such as low voltage and low power consumption, and enabling miniaturization and thinning. In such a liquid crystal display device, various modes have been proposed depending on the alignment state of the liquid crystal in the liquid crystal cell. Conventionally, the TN is in an alignment state twisted by about 90 degrees from the lower substrate to the upper substrate of the liquid crystal cell. (Twisted Nematic) mode was mainstream.

  In general, a liquid crystal display device includes a liquid crystal cell, an optical compensation sheet, and a polarizer. The optical compensation sheet is used for eliminating image coloring and enlarging the viewing angle. The optical compensation sheet is formed, for example, by applying a liquid crystal to a stretched birefringent film or a transparent film. For example, Japanese Patent No. 2587398 discloses a method of manufacturing an optical compensation sheet by applying and aligning a discotic liquid crystal on a TAC film. This optical compensation sheet is applied to a TN mode liquid crystal cell to widen the viewing angle. However, a liquid crystal display device for television that is expected to be viewed from various angles on a large screen has a strict requirement for viewing angle dependency, and it is difficult to satisfy the requirement even when the optical compensation sheet is used. Therefore, liquid crystal display devices different from the TN mode, such as an IPS (In-Plane Switching) mode, an OCB (Optically Compensatory Bend) mode, and a VA (Vertically Aligned) mode, have been studied. In particular, the VA mode is attracting attention as a liquid crystal display device for television applications because of its high contrast and relatively high production yield.

  Further, a film having a high optical anisotropy, that is, a high retardation value is required for an optical compensation sheet (for example, a retardation film) of a liquid crystal display device. In particular, optical compensation sheets for VA mode are required to have a film having an in-plane retardation (Re) of 30 nm to 200 nm and a thickness direction retardation (Rth) of 70 nm to 400 nm. Therefore, a synthetic polymer film having a high retardation value such as a polycarbonate film or a polysulfone film is used as the base film of the optical compensation sheet.

  When a polymer film requires optical anisotropy, that is, a high retardation value, a polycarbonate film or a polysulfone film is used, and the optical isotropy is excellent, that is, when a low retardation value is required. TAC film is used.

  By the way, in recent years, a TAC film having a high retardation value that can be used for applications requiring optical anisotropy is known (see, for example, Patent Document 1). In Patent Document 1, in order to realize a high retardation value with a TAC film, an aromatic compound having at least two aromatic rings, particularly a compound having a 1,3,5-triazine ring, is included as an additive. Stretching in the direction of.

  Generally, TAC is a polymer material that is difficult to stretch, and it is known that it is difficult to increase the birefringence. However, the birefringence can be increased, that is, the retardation value can be increased by incorporating an additive in the film and orienting it by a stretching treatment. Since the TAC film can also serve as a protective film for the polarizing plate, it has an advantage that an inexpensive and thin liquid crystal display device can be provided.

  When an acyl group having 2 to 4 carbon atoms is used as a substituent, the substitution degree of the acetyl group is A, and the substitution degree of the propionyl group or butyryl group is B, (formula) 2.0 ≦ A + B ≦ 3.0 And an optical film containing a cellulose ester that simultaneously satisfies (formula) A <2.4. The film also has a refractive index Nx in the slow axis direction and a refractive index Ny in the traveling axis direction at a wavelength of 590 nm satisfying the expression 0.0005 ≦ Nx−Ny ≦ 0.0050. Such an optical film is known (for example, refer to Patent Document 2). As the polarizing plate used in the VA mode liquid crystal display device, a polarizing plate having a polarizer and an optically biaxial mixed fatty acid cellulose ester film is used. And what is arrange | positioned the said optically biaxial cellulose-ester film between a liquid crystal cell and the said polarizer is also known (for example, refer patent document 3).

  In the solution casting method, a dope is cast on a support to form a cast film. After the cast film has self-supporting properties, it is peeled off as a film (hereinafter referred to as a wet film) wet from the support. The film is conveyed to a tenter dryer and dried while being stretched in the width direction by the tenter dryer. Then, it is further dried and wound up after performing an ear-cleaving process or the like. This film is attached to a polarizing film and used as a polarizing film.

  When the retardation film is bonded to the polarizing film, it is desirable that the slow axis direction coincides with the lateral direction of the polarizing film. Therefore, it is preferable to stretch in the width direction of the film with a tenter dryer. Thus, by extending | stretching during manufacture of a film, the planar shape of a film becomes uniform and planarity becomes favorable. A phenomenon in which the slow axis varies in the width direction due to the bowing phenomenon when the film is stretched in the width direction by a tenter dryer is well known. For example, biaxial stretching of a polyester film obtained by melt film formation has been well studied, and various improved methods have been proposed.

  However, bowing occurs in a concave shape in the advancing direction in the process of performing normal melt film formation and stretching. In contrast, in the solution casting method, bowing occurs in a convex shape in the traveling direction. Therefore, the method for suppressing the occurrence of the bowing phenomenon in the polyester film is not necessarily applicable when the TAC film is manufactured. Therefore, in the production of the TAC film, (1) a cellulose ester having a specific substitution degree is used. (2) Increase the temperature of the edge from the center of the film. (3) Increase the amount of residual solvent at the edge from the center of the film. (4) Provide zones with different temperatures in the tenter dryer. Such a method is known (see, for example, Patent Document 4).

  The tenter dryer includes two tenter chains to which tenter clips are attached. The tenter chain is formed in an endless belt shape by connecting a large number of tenter clips with links. Each tenter chain is wound around two sprockets. One of the sprockets is used as a driving sprocket to which a driving device such as a motor is attached. The position of the driving sprocket is fixed by a spline shaft or the like. The other sprocket rotates freely and supports the movement of the tenter chain as a driven sprocket. The driven sprocket is an open system in order to equalize the tension of the tenter chain.

Then, both ends of the film are gripped and conveyed by tenter clips of two sets of tenter chains. At this time, the width direction of the film can be stretched or relaxed by changing the width of the running path of the tenter chain. If the tenter chain continues to run endlessly to produce film continuously, wear on the link bushing, etc. will cause the tenter chain to stretch, changing the film transport speed and hindering film transport. It has been known. In order to solve this problem, a method of attaching a tenter chain elongation measuring device in the vicinity of a driven sprocket is known. The tenter chain elongation measured by the elongation measuring device is transmitted to the speed correction device. Then, the speed setting value of the line speed setting device is corrected to a desired value, so that the film conveyance speed can be kept substantially constant (see, for example, Patent Document 5).
Japan Society for Invention and Innovation Public Technical Bulletin No. 2001-1745 European Patent Publication 0999656A2 JP 2002-7195 A JP 2002-270442 A JP 2002-296422 A JP-A-10-175254

  The methods described in Patent Documents 2 and 3 are effective in that an inexpensive and thin liquid crystal display device can be obtained. However, in recent years, higher retardation values are required. Therefore, increasing the amount of addition of a retardation control agent (also referred to as an optical anisotropy control agent) or increasing the draw ratio is performed. However, when the wet film is stretched by a tenter dryer, there is a problem that a bowing phenomenon having a bow shape convex in the traveling direction occurs in the width direction of the wet film.

  The method described in Patent Document 4 is a very effective method, but in relation to the quality of recent LCDs such as improvement in contrast ratio and improvement in screen brightness, the axial displacement with respect to the slow axis direction of the film is improved. The demand is getting stricter. For this reason, it is difficult to satisfy the demand for shaft misalignment by the method described in Patent Document 4. In addition, a method of providing different temperature condition sections in the tenter dryer or performing precise temperature control in the width direction of the wet film is preferable because it causes an increase in equipment costs accompanying the complexity of the tenter dryer. It's not a method.

  Conventionally, as described above, Re and Rth are adjusted by adding a retardation control agent to the dope and stretching the wet film in a TD direction (width direction) with a tenter dryer. However, when the manufactured film is used as an optical film constituting an electronic display or the like, variation in film characteristics in the MD direction (longitudinal direction, conveyance direction) is a problem. This problem appears more prominently when the film production rate is increased, and it is difficult to improve productivity. In the tenter dryer described in Patent Document 5, the conveyance speed can be kept substantially uniform. However, there is a problem that even if the conveyance speed is substantially the same, variation in optical characteristics in the MD direction of the film cannot be suppressed.

  An object of the present invention is to provide a polymer film in which axial misalignment is suppressed in at least any one of a longitudinal direction and a width direction.

  The objective of this invention is providing the solution casting method which can manufacture the polymer film by which the axial shift is suppressed in the longitudinal direction and / or the width direction.

  The objective of this invention is providing the tenter type dryer which can manufacture the polymer film by which the axial shift in a longitudinal direction is suppressed.

  As a result of intensive studies by the present inventors, it has been found that the variation in the optical characteristics of the polymer film in the MD direction is caused by the difference in the length of the two sets of tenter chains in the tenter dryer. When a high load is applied to the tenter clip, wear occurs on the bush of the tenter chain link. As a result, a clearance is generated between the individual links, and the lengths of the tenter chains are different. In an extreme case, it has been found that a tenter chain with a total length of several tens of meters has a difference between the left and right lengths, and a subtle angular difference in the extending direction in the TD direction. When the length of the tenter chain is extended, the driven sprocket is displaced, and a desired tension is applied to the tenter chain so that the film is not hindered from being transported.

  Further, as a result of intensive studies by the present inventor, it has been found that the variation in the position of the driven sprocket causes a shaft shift in the MD direction of the polymer film. FIG. 4 shows a graph of the correlation between the moving distance (mm) of the length L (mm) tenter chain and the axial deviation (degree) of the film. As shown in FIG. 4, it was found that an axial shift occurs in a substantially sine wave shape with one cycle when the tenter chain moves L (mm). Therefore, in the present invention, it is possible to make the optical axis variation uniform in the MD direction of the film by setting the difference between the lengths of the left and right tenter chains within a desired range.

  Moreover, it discovered that the axial shift | offset | difference in the TD direction of a film can be suppressed by using what can change the conveyance width of a film for a tenter type dryer. The outline is shown in FIG. The wet film 46 is put into the tenter dryer 120 and stretched in the TD direction by the stretching unit 122. Thereafter, relaxation of the film width is performed by the relaxation unit 123 to obtain the film 125. It has also been found that this stretching relaxation makes it possible to set the axial shift in the TD direction of the film within a desired range (for example, 2 degrees or less).

  The polymer film of the present invention is a polymer film produced by a solution casting method using a tenter dryer having two sets of tenter chains each having a length of L (mm). The tenter chain is manufactured by adjusting the difference in elongation to 0.0001 × L (mm) or less. Alternatively, in a polymer film manufactured by a solution casting method using a tenter dryer provided with two sets of tenter chains, the difference in elongation of the tenter chains is adjusted to 4 mm or less.

  When the tenter chain makes one rotation, it is preferable that the maximum axis shift of the traveling axis in the longitudinal direction of the film is less than 2.0 degrees. The tenter chain is wound around two sprockets, detects the movement of the position of the sprocket due to the elongation of the tenter chain, displaces at least one of the sprockets, and It is preferable that the difference in elongation is adjusted. It is preferable that the tenter chain is formed of Nu links, and the clearance difference between the links is adjusted to 4 mm / Nu or less.

  The axial deviation between the slow axis that is a direction orthogonal to the film transport direction in an arbitrary region of the film and the slow axis of all the regions adjacent to the arbitrary region is less than 2.0 degrees. Is preferred. It is preferable that the said area | region is an area | region for every 50 mm in each direction of the longitudinal direction and the width direction of the said film.

  When drying the film with the tenter dryer, the film is preferably stretched in the width direction of the film and then relaxed in the width direction of the film. When the film is dried by the tenter dryer, it is preferable that the drying temperature of the film is maintained at substantially the same temperature in the range of 50 ° C. or higher and 180 ° C. or lower. The polymer film is preferably an optical film. The polymer film is preferably a cellulose ester film. The polymer film is preferably attached to at least one surface of the polarizing film. It is preferable that the polymer film is attached to at least one surface of a polarizing plate constituting the liquid crystal display device.

  The solution casting method of the present invention comprises two sets of tenter chains having a length of L (mm) after casting a dope containing a polymer and a solvent on the support and then peeling the dope from the support as a film. In the solution casting method in which the film is dried with a tenter dryer, the difference in elongation between the tenter chains on both sides of the tenter chain is adjusted to 0.0001 × L (mm) or less. Alternatively, in the solution casting method of the present invention, a dope containing a polymer and a solvent is cast on a support, and then peeled off from the support as a film, and the film is a tenter dryer provided with two sets of tenter chains. In the solution casting method of drying the tenter chain, the difference in elongation of the tenter chain is adjusted to 4 mm or less.

  The tenter chain is wound around two sprockets, detects the movement of the position of the sprocket due to the elongation of the tenter chain, and displaces at least one of the sprockets based on the detection result. It is preferable to adjust the difference in elongation of the tenter chain. The tenter chain is formed of Nu links, and it is preferable to adjust the clearance difference between the links to 4 mm / Nu or less. When drying the film with the tenter dryer, it is preferable to relax in the width direction of the film after stretching in the width direction of the film. When the film is dried by the tenter dryer, it is preferable that the drying temperature of the film is maintained at substantially the same temperature in the range of 50 ° C. or higher and 180 ° C. or lower. It is preferable that the polymer is a cellulose ester.

  The tenter dryer according to the present invention includes a plurality of gripping means for gripping both edges of the film, two sets of tenter chains to which the plurality of gripping means are attached, and a length of L (mm). In a tenter drier that includes two sprockets around which a chain is wound and a drying unit that dries the film, and that grips and dries the film with the gripping unit, the tenter chain is caused by elongation of the tenter chain Detection means for detecting movement of the position of the sprocket, and a shift mechanism for adjusting the position of the sprocket based on the detection result, and the difference in elongation of the tenter chains on both sides of the tenter chain is 0.0001 × Adjust to L (mm) or less. Alternatively, the tenter dryer according to the present invention includes a plurality of gripping means for gripping both edges of the film, two sets of tenter chains to which the plurality of gripping means are attached, and the respective tenter chains. Two sprockets, and a drying means for drying the film, and in a tenter dryer that grips and dries the film with the gripping means, the position of the sprocket caused by the extension of the tenter chain Detection means for detecting movement and a shift mechanism for adjusting the position of the sprocket based on the detection result are provided, and the difference in elongation of the tenter chain is adjusted to 4 mm or less.

  It is preferable that the tenter chain passes through a path that relaxes after the film is stretched. It is preferable that the drying means maintain the drying temperature of the film at substantially the same temperature in a range of 50 ° C. or higher and 180 ° C. or lower.

  According to the polymer film of the present invention, since the axial misalignment in at least one direction between the longitudinal direction (MD direction) and the width direction (TD direction) is adjusted to less than 2 degrees, the optical film is excellent in optical isotropy. The base film can be preferably used.

  According to the solution casting method of the present invention, two sets of tenter chains having a length of L (mm) are peeled from the support as a film after casting a dope containing a polymer and a solvent on the support. In a solution casting method for drying the film with a tenter dryer comprising: a difference in elongation between tenter chains on both sides of the tenter chain is adjusted to 0.0001 × L (mm) or less, or a polymer and a solvent In a solution casting method in which a dope containing is cast on a support and then peeled from the support as a film and dried with a tenter dryer having two sets of tenter chains, the elongation of the tenter chain Is adjusted to 4 mm or less, so that the maximum axial deviation in the advancing axis (longitudinal direction; MD direction) due to the difference in elongation of the tenter chain is less than 2 degrees. Can do. The polymer film produced by this method is a film having excellent optical isotropy because the maximum axial deviation in the longitudinal direction is suppressed to less than 2 degrees. Therefore, the optical film comprised using the polymer film is excellent in an optical characteristic.

  Further, according to the solution casting method of the present invention, when the film is dried by the method and the tenter dryer, the film is stretched in the width direction of the film and then relaxed in the width direction of the film. Moreover, generation | occurrence | production of the axial shift in the TD direction of a polymer film can also be suppressed. Since this polymer film is excellent in optical isotropy, it can be preferably used as an optical film.

  According to the tenter dryer of the present invention, a plurality of gripping means for gripping both edges of the film, two sets of tenter chains to which the plurality of gripping means are attached and whose length is L (mm), A tenter type dryer that includes two sprockets around which the tenter chain is wound and a drying unit that dries the film, and that grips and dries the film with the holding unit. Detection means for detecting the resulting movement of the sprocket position, and a shift mechanism for adjusting the position of the sprocket based on the detection result, and the difference in elongation between the tenter chains on both sides of the tenter chain is 0.0001. × L (mm) or less or a plurality of gripping means for gripping both edges of the film, and the plurality of gripping means are attached A tenter type comprising: two sets of tenter chains, two sprockets around which each of the tenter chains is wound, and a drying means for drying the film, and gripping and drying the film by the gripping means The dryer includes a detecting means for detecting the movement of the position of the sprocket due to the extension of the tenter chain, and a shift mechanism for adjusting the position of the sprocket based on the detection result, and a difference in extension of the tenter chain Is adjusted to 4 mm or less, it is possible to obtain a polymer film in which the occurrence of axial misalignment in the MD direction due to the difference in length of the tenter chain is prevented.

  According to the tenter type dryer of the present invention, the tenter chain is prevented from occurring in the TD direction in the TD direction of the polymer film by passing through a path that relaxes after stretching the film in the above-described aspect. A polymer film can be obtained. Since this polymer film is excellent in optical isotropy, it can be preferably used as an optical film.

Examples of the polymer used in the present invention include cellulose esters. In addition, as the cellulose acylate which is a kind of cellulose ester, it is preferable to use a cellulose acylate in which the substitution degree of the hydroxyl group of cellulose satisfies all of the following formulas (I) to (III).
(I) 2.5 ≦ A + B ≦ 3.0
(II) 0 ≦ A3.0
(III) 0 ≦ B ≦ 2.9
In the formula, A and B represent the substitution degree of the acyl group substituted with the hydroxyl group of cellulose, A is the substitution degree of the acetyl group, and B is the substitution degree of the acyl group having 3 to 22 carbon atoms. In addition, it is preferable to use particles having 90% by weight or more of TAC of 0.1 mm to 4 mm. In the present invention, polymers other than cellulose esters can be used.

  Glucose units having β-1,4 bonds constituting cellulose have free hydroxyl groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by esterifying some or all of these hydroxyl groups with an acyl group having 2 or more carbon atoms. The degree of acyl substitution means the ratio at which the hydroxyl group of cellulose is esterified at each of the 2-position, 3-position and 6-position (100% esterification has a substitution degree of 1).

  The total acyl substitution degree, that is, DS2 + DS3 + DS6 is preferably 2.00 to 3.00, more preferably 2.22 to 2.90, and particularly preferably 2.40 to 2.88. Further, DS6 / (DS2 + DS3 + DS6) is preferably 0.28 or more, more preferably 0.30 or more, and particularly preferably 0.31 to 0.34. Here, DS2 is the degree of substitution of the hydroxyl group at the 2-position of the glucose unit with an acyl group (hereinafter also referred to as “degree of acyl substitution at the 2-position”), and DS3 is the degree of substitution of the hydroxyl group at the 3-position with an acyl group (hereinafter, referred to as “acyl group”). DS6 is the substitution degree of the hydroxyl group at the 6-position with an acyl group (hereinafter also referred to as “acyl substitution degree at the 6-position”).

  Only one type of acyl group may be used in the cellulose acylate of the present invention, or two or more types of acyl groups may be used. When two or more types of acyl groups are used, one of them is preferably an acetyl group. DSA + DSB where DSA is the total substitution degree of hydroxyl groups at the 2nd, 3rd and 6th positions with an acetyl group and DSB is the total substitution degree with an acyl group other than the acetyl group at the 2nd, 3rd and 6th hydroxyl groups. The value of is more preferably 2.22 to 2.90, and particularly preferably 2.40 to 2.88. The DSB is preferably 0.30 or more, particularly preferably 0.7 or more. Further, 20% or more of the DSB is a substituent of the 6-position hydroxyl group, more preferably 25% or more is a substituent of the 6-position hydroxyl group, more preferably 30%, and particularly 33% or more of the 6-position hydroxyl group. A substituent is also preferred. Furthermore, it is preferable that the substitution value at the 6-position of the cellulose acylate is 0.75 or more, more preferably 0.80 or more, and particularly preferably 0.85 or more. is there. With these cellulose acylates, a solution having a preferable solubility (dope) can be produced. In particular, in a non-chlorine organic solvent, a good solution can be produced. Furthermore, it is possible to prepare a solution having a low viscosity and good filterability.

  Cellulose, which is a raw material for cellulose acylate, may be obtained from either linter cotton or pulp cotton, but is preferably obtained from linter cotton.

  The acyl group having 2 or more carbon atoms of the cellulose acylate of the present invention may be an aliphatic group or an aryl group and is not particularly limited. These are, for example, cellulose alkylcarbonyl esters, alkenylcarbonyl esters, aromatic carbonyl esters, aromatic alkylcarbonyl esters, and the like, each of which may further have a substituted group. Preferred examples of these include propionyl group, butanoyl group, pentanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, iso-butanoyl group , T-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like. Among these, a propionyl group, a butanoyl group, a dodecanoyl group, an octadecanoyl group, a t-butanoyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, a cinnamoyl group, and the like are more preferable, and a propionyl group and a butanoyl group are particularly preferable. is there.

  Other polymers can also be used in the present invention. For example, polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polycarbonate, regenerated cellulose ester, diacetyl cellulose, triacetyl cellulose, norbornene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyether sulfone, polyether ketone, Examples thereof include polyethylene, polypropylene, polyimide, polyamide, and poly-4-methyl-1-pentene.

  Solvents for preparing the dope include aromatic hydrocarbons (eg, benzene, toluene, etc.), halogenated hydrocarbons (eg, dichloromethane, chloroform, chlorobenzene, etc.), alcohols (eg, methanol, ethanol, n-propanol, n-butanol). , Diethylene glycol, etc.), ketones (eg, acetone, methyl ethyl ketone, etc.), esters (eg, methyl acetate, ethyl acetate, propyl acetate, etc.) and ethers (eg, tetrahydrofuran, methyl cellosolve, etc.).

  A halogenated hydrocarbon having 1 to 7 carbon atoms is preferably used, and dichloromethane is most preferably used. From the viewpoint of physical properties such as optical properties such as solubility of TAC, peelability from the support, mechanical strength of the film, etc., it is preferable to mix one to several alcohols having 1 to 5 carbon atoms in addition to dichloromethane. . The content of the alcohol is preferably 2% by weight to 25% by weight and more preferably 5% by weight to 20% by weight with respect to the whole solvent. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, etc., but methanol, ethanol, n-butanol, or a mixture thereof is preferably used.

  Recently, a solvent composition not using dichloromethane has been proposed in order to minimize the influence on the environment. For this purpose, ethers having 4 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, and esters having 3 to 12 carbon atoms are preferable, and these are used by being appropriately mixed. These ethers, ketones and esters may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and —COO—) can also be used as the organic solvent. The organic solvent may have another functional group such as an alcoholic hydroxyl group. In the case of an organic solvent having two or more types of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group.

  Details of the cellulose acylate are described in paragraphs [0141] to [0192] of Japanese Patent Application No. 2003-319673. These descriptions are also applicable to the present invention. Further, as a solvent for cellulose acylate and other additives, plasticizers, deterioration inhibitors, optical anisotropy control agents, dyes, matting agents, release agents, and the like are also disclosed in Japanese Patent Application No. 2003-319673 [0193]. It is described in detail from paragraph to [0513] paragraph.

  The ultraviolet absorber preferably used for the cellulose acylate film of the present invention will be described. The cellulose acylate film of the present invention is used for a polarizing plate or a liquid crystal display member because of its high dimensional stability, but an ultraviolet absorber is preferably used from the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal. As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Specific examples of the ultraviolet absorber preferably used in the present invention include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

  Although the specific example as a benzotriazole type ultraviolet absorber is listed below, this invention is not limited to these. 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzotriazole, 2- (2′-hydroxy-3) '-Tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy -3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethyl) Butyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotria 2,4-dihydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-5-benzoylphenylmethane) ), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2′-hydroxy-3 ′) , 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole, 2,6- Di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl Propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2, 2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1,3,5 Trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, etc. Is mentioned. In particular, (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2′-hydroxy-3 ′, 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzotriazole, 2,6-di -Tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl -5-methyl-4-hydroxyphenyl) propionate], for example, N, N'-bis [3- (3,5-di-tert-butyl-4-hydroxy). A hydrazine-based metal deactivator such as (cyphenyl) propionyl] hydrazine or a phosphorus-based processing stabilizer such as tris (2,4-di-tert-butylphenyl) phosphite may be used in combination. Is preferably 1 ppm to 2.0% by mass relative to the cellulose acylate, more preferably 10 ppm to 5000 ppm.

Moreover, the ultraviolet absorbers described in JP-A-6-148430 and JP-A-7-11056 can also be preferably used. The ultraviolet absorber described above preferably used in the present invention has high transparency, is excellent in the effect of preventing the deterioration of the polarizing plate and the liquid crystal element, and is particularly preferably a benzotriazole-based ultraviolet absorber with less unnecessary coloring. The amount of the UV absorber used is not uniform depending on the type of compound and the use conditions, but is usually preferably 0.2 to 5.0 g, more preferably 0.4 to 1.5 g per 1 m ^{2 of the} cellulose acylate film. Preferably, 0.6g-1.0g is especially preferable.

  In addition, the light stabilizers listed in the catalog “Adeka Stub”, an outline of additives for Asahi Denka Plastics, can also be used. Light stabilizers and UV absorbers from Ciba Special Chemicals' Tinuvin Product Guide can also be used. SEESORB, SEENOX, SEETEC, etc. listed in the catalog of SHIPRO KASEI KAISYA can also be used. Jouhoku Chemical's UV absorbers and antioxidants can also be used. UV absorbers from Kyosho's VIOSORB and Yoshitomi Pharmaceutical can also be used.

  Regarding the spectral transmittance in the ultraviolet region, Japanese Patent Application Laid-Open No. 2003-043259 discloses a 390 nm necessary for obtaining an optical film, a polarizing plate and a display device excellent in color reproducibility and durability in ultraviolet irradiation. An optical film having a spectral transmittance of 50% to 95% at 350 nm and a spectral transmittance of 350% at 350 nm is described.

  Furthermore, the compound used as an optical anisotropy control agent (retardation control agent) will be described in detail.

In general formula (2) shown in Chemical Formula ¹ , R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are each independently a hydrogen atom, Alternatively, it represents a substituent, and the substituent T described below can be applied to the substituent. At least one of R ¹ , R ² , R ³ , R ⁴ and R ⁵ represents an electron donating group. Preferably, one of R ¹ , R ³ or R ⁵ is an electron donating group, and R ³ is more preferably an electron donating group.

  The electron donating group represents one having a Hammet's σp value of 0 or less, and those having a Hammet's σp value of 0 or less described in Chem. Rev., 91, 165 (1991) are preferably applicable. -0.85 to 0 are used. Examples thereof include an alkyl group, an alkoxy group, an amino group, and a hydroxyl group.

  The electron donating group is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably carbon). 1 to 4).

R ¹ is preferably a hydrogen atom or an electron donating group, more preferably an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably an alkyl group having 1 to 4 carbon atoms or a carbon number 1 to 12 Particularly preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). Most preferred is a methoxy group.

R ² is preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group or a hydroxyl group, more preferably a hydrogen atom, an alkyl group or an alkoxy group, still more preferably a hydrogen atom or an alkyl group (preferably a carbon number). 1 to 4, more preferably a methyl group), an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to carbon atoms). 4). Particularly preferred are a hydrogen atom, a methyl group and a methoxy group.

R ³ is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, still more preferably an alkyl group or an alkoxy group, particularly preferably. An alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). Most preferred are n-propoxy group, ethoxy group and methoxy group.

R ⁴ is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. , An alkoxy group having 1 to 12 carbon atoms (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms), particularly preferably. Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and most preferably a hydrogen atom, a methyl group, or a methoxy group.

R ⁵ is preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group or a hydroxyl group, more preferably a hydrogen atom, an alkyl group or an alkoxy group, still more preferably a hydrogen atom or an alkyl group (preferably a carbon number). 1 to 4 is more preferably a methyl group), an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). It is. Particularly preferred are a hydrogen atom, a methyl group and a methoxy group.

R ⁶ , R ⁷ , R ⁹ and R ¹⁰ are preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a halogen atom, more preferably a hydrogen atom or a halogen atom. More preferably a hydrogen atom.

R ⁸ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy having 6 to 12 carbon atoms. Group, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom, which may have a substituent if possible. The group T can be applied.

R ⁸ is preferably an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryloxy group having 2 to 12 carbon atoms. And more preferably an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms, still more preferably an alkoxy group having 1 to 12 carbon atoms (preferably Is preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and particularly preferably a methoxy group, an ethoxy group, n-propoxy group, iso-propoxy group and n-butoxy group.

  Of the general formula (2), the following general formula (2-A) is more preferable.

R ¹¹ in the general formula (2-A) represents an alkyl group. R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent. R ⁸ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an aryloxy having 6 to 12 carbon atoms. Group, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a cyano group, or a halogen atom. In general formula (2-A), R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ have the same meanings as those in general formula (2), and The preferable range is also the same.

In the general formula (2-A), R ¹¹ represents an alkyl group having 1 to 12 carbon atoms, and the alkyl group represented by R ¹¹ may be linear or branched, and further has a substituent. However, it is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms, and particularly preferably an alkyl group having 1 to 4 carbon atoms. (For example, a methyl group, an ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, etc. are mentioned).

  Of the general formula (2), the following general formula (2-B) is more preferable.

In the general formula (2-B), R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent. R ¹¹ represents an alkyl group having 1 to 12 carbon atoms. X is an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, a carbon number A 2-12 alkoxycarbonyl group, a C2-C12 acylamino group, a cyano group, or a halogen atom is represented.

In the general formula (2-B), R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ have the same meanings as those in the general formula (2), and the preferred range is also It is the same. R ¹¹ in the general formula (2-B) has the same meaning as R ¹¹ in the general formula (2-A), the preferred ranges are also the same.

  In general formula (2-B), X is an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and the number of carbon atoms. It represents a 6-12 aryloxy group, a C2-C12 alkoxycarbonyl group, a C2-C12 acylamino group, a cyano group or a halogen atom.

When all of R ¹ , R ² , R ⁴ and R ⁵ are hydrogen atoms, X is preferably an alkyl group, alkynyl group, aryl group, alkoxy group or aryloxy group, more preferably an aryl group, alkoxy group Group, aryloxy group, more preferably alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms). And particularly preferably a methoxy group, a methoxy group, an n-propoxy group, an iso-propoxy group or an n-butoxy group.

When at least one of R ¹ , R ² , R ⁴ or R ⁵ is a substituent, X is preferably an alkynyl group, an aryl group, an alkoxycarbonyl group, or a cyano group, more preferably an aryl group (preferably Is a cyano group or an alkoxycarbonyl group (preferably a carbon number of 2 to 12), more preferably an aryl group (preferably an aryl group of 6 to 12 carbon atoms, more preferably a phenyl group). , P-cyanophenyl group and p-methoxyphenyl group), an alkoxycarbonyl group (preferably having a carbon number of 2-12, more preferably having a carbon number of 2-6, still more preferably having a carbon number of 2-4, particularly preferably methoxy. Carbonyl, ethoxycarbonyl, n-propoxycarbonyl), cyano group, particularly preferably phenyl group, methoxy group. A sicarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, and a cyano group.

  Of the general formula (2), the following general formula (2-C) is more preferable.

In the general formula (2-C), R ¹ , R ² , R ⁴ , R ⁵ , R ¹¹ and X have the same meanings as those in the general formula (2-B), and preferred ranges are also the same.

Among the compounds represented by the general formula (2), a compound represented by the following general formula (2-D) is preferable.

In the general formula (2-D), R ² , R ⁴ and R ⁶ have the same meanings as those in the general formula (2-C), and preferred ranges are also the same. R ²¹ and R ²² are each independently an alkyl group having 1 to 4 carbon atoms. X ¹ is an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, or a cyano group.

R ²¹ represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, and more preferably an ethyl group or a methyl group. R ²² represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group or a methyl group, and still more preferably a methyl group.

X ¹ is an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, or a cyano group, preferably an aryl group having 6 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, or a cyano group. More preferably a phenyl group, a p-cyanophenyl group, a p-methoxyphenyl group, a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, and a cyano group, still more preferably a phenyl group, a methoxycarbonyl group. , An ethoxycarbonyl group, an n-propoxycarbonyl group, and a cyano group.

  Of the general formula (2), the following general formula (2-E) is most preferable.

In the general formula (2-E), R ² , R ⁴ and R ⁵ have the same meanings as those in the general formula (2-D), and the preferred range is also the same, but one of them is represented by —OR ¹³ . (R ¹³ is an alkyl group having 1 to 4 carbon atoms). R ²¹ , R ²² and X ¹ have the same meanings as those in formula (2-D), and preferred ranges are also the same.

In the general formula (2-E), R ² , R ⁴ and R ⁵ have the same meanings as those in the general formula (2-D), and the preferred range is also the same, but one of them is represented by —OR ¹³ . (R ¹³ is an alkyl group having 1 to 4 carbon atoms), preferably R ⁴ and R ⁵ are groups represented by —OR ¹³ , more preferably R ⁴ is —OR ^13. It is group represented by these. R ¹³ represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group or a methyl group, and still more preferably a methyl group.

  The aforementioned substituent T will be described below. Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms such as methyl, ethyl, iso-propyl, tert-butyl, and n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2-8, and examples thereof include propargyl and 3-pentynyl).

  For example, an aryl group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms, such as phenyl, p-methylphenyl, naphthyl, etc.), substitution Or an unsubstituted amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc. An alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), An aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, Phenyloxy, 2-naphthyloxy and the like.), And also like.

  For example, an acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, pivaloyl and the like), alkoxycarbonyl. A group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), an aryloxycarbonyl group (preferably 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl, etc.), acyloxy group (preferably 2 to 20 carbon atoms, more preferably Has 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy, benzo Aryloxy and the like.) May also be mentioned, such as.

  For example, an acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), alkoxycarbonylamino group (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino), aryloxycarbonylamino group (preferably having carbon number) 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino, and the like, and sulfonylamino groups (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms. Amino, such as benzenesulfonylamino and the like.), And also like.

  For example, a sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl ), A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc. An alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio and ethylthio), an arylthio group. (Preferably 6-20 carbon atoms, more preferably 6-6 carbon atoms. 6, particularly preferably 6 to 12 carbon atoms, such as phenylthio and the like.), And also like.

  For example, a sulfonyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms such as mesyl, tosyl, etc.), sulfinyl group (preferably carbon 1 to 20, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably 1 to 20 carbon atoms, more Preferably it is C1-C16, Most preferably, it is C1-C12, for example, a ureido, methylureido, phenylureido etc. are mentioned), phosphoric acid amide groups (preferably C1-C20, More preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenyl phosphoric acid amide And the like.) It may also be mentioned, such as.

  For example, hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group A heterocyclic group (preferably having a carbon number of 1 to 30, more preferably 1 to 12, and examples of the hetero atom include a nitrogen atom, an oxygen atom and a sulfur atom. Specific heterocyclic groups include: For example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), a silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, Particularly preferably, it has 3 to 24 carbon atoms, for example, trimethylsilyl, triphenyl Such as silyl and the like), and the like. These substituents may be further substituted. Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

  Hereinafter, the compound represented by the general formula (2) will be described in detail with specific examples, but the present invention is not limited to the following specific examples.

  The compound represented by the general formula (2) can be synthesized by a general ester reaction of a substituted benzoic acid and a phenol derivative, and any reaction may be used as long as it is an ester bond forming reaction. Examples thereof include a method of converting a substituted benzoic acid to an acid halide and then condensing with phenol, a method of dehydrating the substituted benzoic acid and a phenol derivative using a condensing agent or a catalyst, and the like. In view of the production process and the like, a method in which the substituted benzoic acid is functionally converted to an acid halide and then condensed with phenol is preferable.

  Reaction solvents include hydrocarbon solvents (preferably toluene and xylene), ether solvents (preferably dimethyl ether, tetrahydrofuran, dioxane, etc.), ketone solvents, ester solvents, acetonitrile, dimethylformamide, dimethyl Acetamide or the like can be used. These solvents may be used alone or in admixture of several kinds, and preferred reaction solvents are toluene, acetonitrile, dimethylformamide and dimethylacetamide.

  The reaction temperature is preferably 0 to 150 ° C, more preferably 0 to 100 ° C, still more preferably 0 to 90 ° C, and particularly preferably 20 ° C to 90 ° C. In this reaction, it is preferable not to use a base. When a base is used, either an organic base or an inorganic base may be used, preferably an organic base such as pyridine, tertiary alkylamine (preferably triethylamine, ethyldiisopropyl). Pyramine and the like).

The optical properties of the cellulose acylate film of the present invention are as follows:
Formula (IV): Re (λ) = (nx−ny) × d,
Formula (V): Rth (λ) = {(nx + ny) / 2−nz} × d,
Re retardation value and Rth retardation value represented by the following formula (VI)
And (VII) is preferably satisfied.
Formula (VI): 46 nm ≦ Re (630) ≦ 200 nm
Formula (VII): 70 nm ≦ Rth (630) ≦ 350 nm
[Where Re (λ) is the front retardation value at wavelength λ nm (unit: nm), Rt
h (λ) is a retardation value (unit: nm) in the film thickness direction at the wavelength λ nm. Further, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the thickness of the film. That's it. ]
More preferably, the following formulas (VIII) and (IX) are satisfied.
Formula (VIII): 46 nm ≦ Re (630) ≦ 100 nm
Formula (IX): 180 nm ≦ Rth (630) ≦ 350 nm

The optical characteristic values of Re and Rth change with changes in humidity, mass changes and dimensional changes with time. The smaller the values of Re and Rth, the better. In addition to using cellulose acylate with a high degree of acyl substitution at the 6-position in order to reduce changes in optical properties due to humidity, by using various hydrophobic additives (plasticizer, retardation developer, ultraviolet absorber, etc.) Reduce the moisture permeability and equilibrium moisture content of the film. The preferred moisture permeability is 400 to 2300 g per square meter at 60 ° C. and 95% RH for 24 hours. A preferable equilibrium water content is 3.4% or less at 25 ° C. and 80% RH. When the humidity at 25 ° C. is changed from 10% RH to 80% RH, the amount of change in optical characteristics is preferably 12 nm or less in Re value and 32 nm or less in Rth value. A preferred amount of the hydrophobic additive is from 10% to 30%, more preferably from 12% to 25%, particularly preferably from 14.5% to 20%, based on cellulose acylate. When the additive is volatile or decomposable and changes in the mass or dimensionality of the film occur, optical properties change. Therefore, it is preferable that the mass change amount of the film after aging at 80 ° C. and 90% RH for 48 hours is 5% or less. Similarly, the dimensional change after 24 hours at 60 ° C. and 95% RH is preferably 5% or less. Even if there is a small dimensional change or mass change, if the photoelastic coefficient of the film is small, the amount of change in optical characteristics is small. Accordingly, the photoelastic coefficient of the film is preferably 50 × 10 ⁻¹³ cm ² / dyne or less.

  The method for producing the dope used in the present invention is not particularly limited. A specific example will be described. A mixed solvent to which alcohol is added using dichloromethane as a main solvent is used. TAC and a plasticizer (for example, triphenyl phosphate, biphenyl diphenyl phosphate) are added to the mixed solvent and dissolved by stirring to obtain a dope (hereinafter referred to as a raw material dope). In addition, when melt | dissolving, solubility can be improved by heating or cooling. Further, an additive solution (hereinafter referred to as an additive solution) is prepared by mixing and dissolving a raw material dope, a mixed solvent, and an ultraviolet absorber (for example, a benzotriazole compound is preferable). Further, an additive solution (hereinafter referred to as a matting agent solution) is prepared by mixing and dispersing a raw material dope, a mixed solvent, and a matting agent (for example, silica particles). Furthermore, an additive solution containing a deterioration inhibitor, an optical anisotropy control agent (retardation control agent), a dye, a pigment, a release agent and the like may be prepared and used according to the purpose.

  After preparing the raw material dope and the additive solution, it is preferable to perform filtration with a filtration device in order to remove impurities. As the filtration device, it is preferable to use a filtration filter having an average pore diameter of 100 μm or less and a filtration flow rate of 50 L / hr or more. After that, it is preferable to defoam the raw material dope and the additive solution. Any known method can be applied to remove bubbles.

  The materials, raw materials, additive dissolution method, filtration method, defoaming, and addition method in the solution casting method for obtaining a TAC film are described in detail in paragraphs [0514] to [0608] of Japanese Patent Application No. 2003-319673. These descriptions are also applicable to the present invention.

  FIG. 1 shows a film production line 10. The stock tank 11 contains an additive liquid 12. The stock tank 13 contains a matting agent solution 14. A raw material dope 16 is placed in the stock tank 15. Pumps 17, 18, 19 for feeding the liquids 12, 14, 16 therein are attached to the respective stock tanks 11, 13, 15.

  After the additive solution 12 is mixed with the matting agent solution 14, a uniform additive solution is made by the static mixer 20. Furthermore, after this additive solution is mixed with the raw material dope 16, the solution is made uniform by the static mixer 21. Hereinafter, this liquid is referred to as casting dope. The dope for casting is filtered by the filtration device 22 and then fed to the casting die 30.

  It is preferable to mix the raw material dope 16 and an additive liquid (for example, an ultraviolet absorber liquid) added to the raw material dope 16 using an in-line mixer (for example, a static mixer) that mixes during the transfer. It is more preferable to perform mixing by connecting a plurality of in-line mixers having different mixing methods in series.

  As the in-line mixer, it is preferable to include at least one of a static mixer and a through the mixer. When the static mixer is provided, the number of elements of the static mixer is preferably 6 or more and 90 or less (more preferably, 6 or more and 60 or less).

  In the case where both a static mixer and a slew mixer are provided, the slew mixer is preferably arranged on the upstream side of the static mixer. Further, the distance between the through-the-mixer and the addition port for adding the additive liquid is preferably 5 mm or more and 150 mm or less, and further, the distance between the through-the-mixer and the addition port for adding the additive liquid is 5 mm or more and 15 mm or less. Is more preferable. Moreover, it is preferable that the upstream edge part of the element which comprises a through-zer mixer is located in the inner wall vicinity of the piping through which the said raw material dope flows.

  Furthermore, it is preferable that a first filtration device for filtering the raw material dope is provided on the upstream side of the in-line mixer, and an additive is added to the raw material dope after filtration by the first filtering device, and further, the downstream side of the in-line mixer It is more preferable that a second filtering device for filtering the dope is provided, and the dope mixed by the in-line mixer is filtered by the second filtering device.

In addition, the present invention preferably satisfies the following.
(1) When the flow rate of the additive solution is V1 and the flow rate of the raw material dope is V2, 1 ≦ V1 / V2 ≦ 5.
(2) The additive ratio of the additive liquid is 0.1% to 50% in flow rate ratio.
(3) When the viscosity of the additive solution is N1 and the viscosity of the raw material dope is N2, 1000 ≦ N2 / N1 ≦ 100000 is satisfied, and at 20 ° C., 5000 cP ≦ N1 ≦ 500000 cP, and 0 .1 cP ≦ N2 ≦ 100 cP.
(4) The shear rate of the raw material dope is 0.1 (1 / s) to 30 (1 / s).
(5) The polymer is cellulose acylate.
(6) The additive solution is a solution containing the main solvent of the polymer solution.
(7) The additive solution is a solution containing the main solvent of the polymer solution and has a composition different from that of the raw material dope.
(8) The additive solution is a solution containing the main solvent of the polymer solution, and contains at least one ultraviolet absorber.
(9) The additive solution is a solution containing the main solvent of the polymer solution, and is formed by dispersing at least one kind of inorganic or organic fine particles.
(10) The additive solution is a solution containing the main solvent of the polymer solution and contains at least one type of peeling accelerator.
(11) The additive solution is a solution containing the main solvent of the polymer solution and contains at least one kind of poor solvent.

  A casting band 33 is provided below the casting die 30 so as to span the rotating rollers 31 and 32. The casting band 33 travels endlessly as the rotating rollers 31 and 32 are rotated by a driving device (not shown). The moving speed of the casting band 33, that is, the casting speed is preferably 10 m / min to 200 m / min. In order to set the surface temperature of the casting band 33 to a desired temperature, it is preferable that the heat transfer medium circulation device 34 is attached to the rotary rollers 31 and 32. A heat transfer medium flow path is formed in the rotating rollers 31 and 32, and a heat transfer medium maintained at a predetermined temperature passes through the flow path. Thereby, the temperature of the rotating rollers 31 and 32 is maintained at a predetermined temperature. Then, the surface temperature of the casting band 33 becomes a desired temperature. The surface temperature of the casting band 33 is preferably −20 ° C. to 40 ° C.

  The casting die 30, the casting band 33 and the like are accommodated in the casting chamber 35. A temperature control facility 36 is attached to keep the temperature in the casting chamber 35 at a predetermined temperature. The temperature of the casting chamber 35 is preferably -10 ° C to 57 ° C. Further, a condenser (condenser) 37 for condensing and recovering the volatile organic solvent is provided. The condensed organic solvent is recovered and regenerated by the recovery device 38 and then reused as a dope preparation solvent.

  A casting film 39 is formed by casting the casting dope from the casting die 30 onto the casting band 33 while forming a casting bead. In addition, it is preferable that the temperature of dope for casting at this time is -10 degreeC-57 degreeC. In order to stabilize the formation of the casting bead, the decompression chamber 40 is preferably attached to the rear surface of the casting bead. The casting bead is stabilized by setting the decompression chamber 40 to a desired pressure. The casting film 39 moves as the casting band 33 travels. Blower ports 41, 42, 43 for evaporating the solvent in the casting film 39 are provided on the peripheral surface of the casting band 33. Further, in order to suppress the surface variation of the film surface due to the drying air being blown onto the casting film 39 immediately after casting, a wind shielding plate 44 is provided at the air blowing port 41 in the vicinity of the casting die 30. preferable. In addition, although the example which uses the casting band as a support body is shown in FIG. 1, it is also possible to use a casting drum. In this case, the surface temperature of the casting drum is preferably -20 ° C to 40 ° C.

  After the casting film 39 has self-supporting properties, the casting film 39 is peeled off from the casting band 33 as a film (hereinafter referred to as a wet film) 46 while being supported by the peeling roller 45. Thereafter, the transfer section 50 provided with a plurality of rollers is conveyed, and then fed into the tenter dryer 60. In the crossover part 50, the drying of the wet film 46 is advanced by sending the drying air of desired temperature from the air blower 51. FIG. The drying air temperature is preferably 20 ° C to 250 ° C. In the crossover section 50, it is possible to impart a draw in the transport direction of the wet film 46 by making the rotational speed of the downstream roller faster than the rotational speed of the upstream roller. In the tenter dryer 60, the wet film 46 is dried while being gripped and transported by clips at both edges. The conveyance by the tenter dryer 60 will be described in detail later.

  The wet film 46 is dried to a desired volatile content by a tenter dryer 60 and sent out as a film 61. Both edges of the film 61 are cut by the edge-cutting device 62. Both the cut edges are sent to the crusher 63 by a cutter blower (not shown). Both edges of the film are crushed by the crusher 63 to form chips. It is advantageous in terms of cost to reuse this chip for dope preparation. In addition, although the process of cut | disconnecting the both edges of this film can also be abbreviate | omitted, it is preferable to carry out in any one from casting to winding up a film.

  The film 61 is sent to a drying chamber 65 in which a large number of rollers 64 are provided. Although the temperature in the drying chamber 65 is not specifically limited, It is preferable that it is the range of 50 to 200 degreeC. In the drying chamber 65, the film 61 is conveyed while being wound around the roller 64, and the organic solvent is volatilized and dried. An adsorption recovery device 66 is attached to the drying chamber 65. The volatile solvent is adsorbed and recovered by the adsorption recovery device 66. The air from which the solvent component has been removed is blown into the drying chamber 65 as dry air again. The drying chamber 65 is more preferably divided into a plurality of sections in order to change the drying temperature. In addition, providing a preliminary drying chamber (not shown) between the ear-clipping device 62 and the drying chamber 65 to perform preliminary drying of the film 61 can suppress a change in the shape of the film 61 due to a rapid increase in the film temperature. Therefore, it is more preferable.

  The film 61 is conveyed to the cooling chamber 67 and cooled to approximately room temperature. A conditioning room (not shown) may be provided between the drying chamber 65 and the cooling chamber 67. Air adjusted to a desired humidity and temperature is blown onto the film 61 in a conditioning room. Thereby, generation | occurrence | production of the winding defect at the time of winding up the film 61 can be suppressed.

  It is preferable to provide the forced static elimination device (static elimination bar) 68 so that the charged voltage during the conveyance of the film 61 falls within a predetermined range (for example, −3 kV to +3 kV). In FIG. 1, an example provided on the downstream side of the cooling chamber 67 is illustrated, but the position is not limited thereto. Furthermore, it is preferable to provide a knurling roller 69 and to impart knurling to both edges of the film 61 by embossing. In addition, it is preferable that the unevenness | corrugation of the knurled location is 1 micrometer-200 micrometers.

  Finally, the film 61 is wound up by the winding roller 71 in the winding chamber 70. At this time, it is preferable to wind the sheet while applying a desired tension with the press roller 72. More preferably, the tension is gradually changed from the start to the end of winding. The film 61 to be wound is preferably at least 100 m in the longitudinal direction (casting direction). The width direction is preferably 600 mm or more, and more preferably 1400 mm or more and 1800 mm or less. It is also effective when it is wider than 1800 mm. The thickness of the film 61 can also be applied when manufacturing a thin film having a thickness of 15 μm to 100 μm.

  A solution casting method according to the present invention and a tenter dryer 60 used in the method will be described with reference to FIG. The tenter dryer 60 is provided with a large number of tenter clips 80 and 81. The tenter clips 80 and 81 are connected to each other by links (see FIG. 3) and are tenter chains 82 and 83 that can travel endlessly. The tenter chains 82 and 83 are wound around driving sprockets 84 and 85 and driven sprockets 86 and 87, respectively. A motor 88 is connected to the driving sprockets 84 and 85. Further, tenter rails 89 and 90 are provided for guiding the movement of the tenter chains 82 and 83 along the route.

  As the motor 88 rotates, the driving sprockets 84 and 85 are driven to rotate. The tenter chains 82 and 83 wound around the driving sprockets 84 and 85 travel endlessly with the rotation. Sensors 91 and 92 for detecting displacement of the driven sprockets 86 and 87 accompanying the extension of the length of the tenter chains 82 and 83 are provided in the vicinity of the driven sprockets 86 and 87. Shift mechanisms 93 and 94 for adjusting the displacements are attached to the driven sprockets 86 and 87. The shift mechanisms 93 and 94 adjust the displacement of the driven sprockets 86 and 87 based on the detection results detected by the sensors 91 and 92 to adjust the difference in length between the tenter chains 82 and 83. Further, by adjusting the displacement of the driven sprockets 86 and 87, a desired tension is applied to the tenter chains 82 and 83, and the movement of the tenter chains 82 and 83 is stabilized.

  An enlarged view of the main part of the tenter chain 82 is shown in FIG. The configuration of the tenter chain 83 is the same. The tenter chain 82 includes a number of tenter clips 80a, 80b, and 80c. The tenter clip 80 b is connected to adjacent tenter clips 80 a and 80 c by links 100 and 101. The link 100 is formed by plates 102 and 103 and rollers 104 and 105 sandwiched therebetween. Similarly, the link 101 is formed of plates 106 and 107 and rollers 108 and 109. Each link 100, 101 is sandwiched between the tenter clip 80 b and the outer plate 111, and further fastened with bolts 112, 113 to constitute a tenter chain 82. The distance between the centers of the adjacent links 100 and 101 is referred to as an inter-link distance L1 (mm). In the present invention, the inter-link distance L1 (mm) is preferably in the range of 50 mm to 200 mm, more preferably 80 mm to 150 mm.

  While the tenter chains 82 and 83 travel endlessly, a clearance is generated between the links, and the lengths of the tenter chains 82 and 83 are extended. FIG. 4 shows the moving distance (mm) of the tenter chain and the axial deviation (degree) of the film. It can be seen that the axis shift shows a fluctuation approximated by a sine wave when the moving distance of the tenter chain is every L (mm), that is, while the tenter chain makes one round (approximately one cycle). The inventor has found that this variation is caused by a difference in length between the tenter chains 82 and 83. Therefore, by suppressing the difference between the lengths of the tenter chains 82 and 83 within a desired range, the maximum axial shift in the MD direction of the film 61 is suppressed to less than 2 degrees.

  In the present invention, the length L (mm) of the tenter chain is not particularly limited, but it is preferable to use a tenter chain having a length in the range of 30 m to 150 m, more preferably 40 m to 130 m, and most preferably. Is 40 m or more and 100 m or less. In this case, the difference between the lengths of the tenter chains 82 and 83 is preferably 0.0001 × L (mm) or less, more preferably 0.00005 × L (mm), and most preferably 0.0. It is less than 00001 × L (mm). The lower limit of the difference is most preferably substantially 0 mm, but is practically acceptable up to about 0.005 × L (mm). More specifically, the difference in length between the tenter chains 82 and 83 is preferably 4 mm or less, more preferably 0 mm or more and 3 mm or less, and most preferably 0 mm or more and 2 mm or less.

  The difference between the lengths of the tenter chains 82 and 83 can be measured by detecting the displacement of the driven sprockets 86 and 87 by sensors 91 and 92 provided in the vicinity of the driven sprockets 86 and 87. When the difference in the lengths of the tenter chains 82 and 83 exceeds the predetermined range, the positions of the driven sprockets 86 and 87 are moved by the shift mechanisms 93 and 94 to adjust the difference in the lengths of the tenter chains 82 and 83. To do.

  The number Nu (number) of links used in the present invention is not particularly limited. However, it is preferably 200 or more and 2000 or less, more preferably 300 or more and 1500 or less, and most preferably 300 or more and 800 or less. In the present invention, the difference between the lengths of the tenter chains 82 and 83 is adjusted by setting the variation in the distance L1 (mm) between the slits 100 and 101 (hereinafter referred to as the distance between the slits) to a predetermined range. Is also possible. Note that the distance between the slits when the clearance is generated between the slits is L1 ′ (mm). The clearance difference (| L1−L1 ′ |) is preferably 4 mm / Nu or less, more preferably 3 mm / Nu or less, and most preferably 2 mm / Nu or less.

  By satisfying the above conditions and performing film formation, the maximum axis deviation in the traveling axis (film conveyance, longitudinal direction; MD direction) can be made 2 degrees or less, and more experimental conditions can be selected. It can be set to 1 degree or less, and further can be set to 0.5 degree or less.

  In the present invention, by using a tenter dryer that can relax the stretching of the film, it is also possible to suppress axial misalignment in the slow axis direction (direction perpendicular to the film transport direction). Axial misalignment can be suppressed to less than 2 degrees by adjusting the experimental conditions, and can be set to 1 degree or less by selecting more experimental conditions, and further to 0.5 degrees or less. Is also possible.

  The stretching relaxation of the wet film 46 in the tenter dryer 120 will be described with reference to FIG. The wet film 46 peeled off from the casting band 33 as a support is transported by the transfer section 50 and dried to become a desired residual volatile matter (mainly an organic solvent) and sent to the tenter dryer 120. . The residual volatile content is not particularly limited, but is preferably 10% by weight or more and 290% by weight or less, more preferably 10% by weight or less, based on the dry weight based on 100% by weight of the film after complete drying. It is 10 to 120% by weight, and most preferably 20 to 80% by weight.

  In the tenter dryer 120, both ends of the wet film 46 are conveyed while being gripped by gripping means (for example, a clip or the like), and are stretched and relaxed in the width direction by changing the width of the gripping means. The wet film 46 is gripped by a clip (not shown) at the tenter dryer inlet 120a. The tenter dryer 120 is composed of four sections according to clips (not shown). For preheating and drying of the wet film 46, the entrance part 121 having a substantially constant width, the extending part 122 for expanding the grip width of the film, the relaxation part 123 for contracting the grip width of the film, and the film after being relaxed It is the exit part 124 which makes a width | variety constant. The clip is opened at the tenter dryer outlet 120 b of the outlet portion 124 and is sent out from the tenter dryer 120 as a film 125.

  “Substantially constant width” at the inlet portion 121 and the outlet portion 124 means that the difference between the film gripping width at the start point of the section and the film gripping width at the end point is within ± 2%. is doing. Since the wet film 46 contains residual volatile components, the organic solvent continuously volatilizes from the inlet portion 121 through the outlet portion 124. Various known methods can be used as the means for volatilizing the organic solvent, but the method of spraying hot air on the wet film 46 and drying it is the most preferable method from the viewpoint of equipment cost.

  The temperature at which the wet film 46 is dried (hereinafter referred to as the drying temperature) is preferably set to substantially the same temperature. By making the drying temperature substantially the same, the volatilization rate of the organic solvent that volatilizes from the wet film 46 can be adjusted. Thereby, it becomes possible to make the amount of solvent contained in the width direction (TD direction) of the wet film 46 substantially uniform, and the occurrence of partial shrinkage of the wet film 46 is suppressed. Although a drying temperature is not specifically limited, It is preferable that it is the range of 50 to 180 degreeC. If it is lower than 50 ° C., the volatilization of the organic solvent from the wet film 46 becomes too slow, and the productivity of the film 125 may be reduced. Moreover, when it exceeds 180 degreeC, the bumping of the containing organic solvent may arise from the wet film 46 surface vicinity, and there exists a possibility that a film surface shape may deteriorate.

  In the present invention, the slow axis direction is defined by defining the stretching relaxation conditions of the wet film (used in the following description to include the state of the film 125) 46 in the tenter dryer 120. This makes it possible to set the desired axis deviation.

  As shown in FIG. 5, the wet film 46 is held at both ends by tenter clips (not shown) at the entrance 120a. The width of the tenter clip at this time (hereinafter also referred to as the biting width) is L2 (mm). A number of tenter clips are connected to the tenter chain. The tenter chain travels endlessly by meshing with the driving and driven sprockets. Thereafter, as the tenter chain to which the tenter clip is connected moves, the tenter clip moves to the extending portion 122 where the width of the tenter clip is increased. Let the maximum stretch width in the stretch part 122 be L3 (mm). Thereafter, the width of the wet film 46 is contracted by the relaxing portion 123. Note that a constant clip width after relaxation (hereinafter also referred to as a separation width) is L4 (mm).

In the present invention, the maximum stretching ratio Lmax (%) and the separation stretching ratio Lout (%) are defined by the following equations.
Lmax (%) = {(L3 / L2) −1} × 100
Lout (%) = {(L4 / L2) −1} × 100
The relaxation rate LL (%) is defined as LL = Lmax−Lout.
Therefore, when the relaxation rate LL is transformed into the equations L2, L3, and L4,
LL = (L3-L4) / L2 × 100.

In the present invention, the relaxation rate LL (%) is
The range of 1 <LL <15 is preferable, more preferably 3 <LL <9, and most preferably 5 <LL <7.5. If the relaxation rate LL (%) is 1 or less, relaxation is not performed, and a slow axis misalignment due to the Boeing phenomenon remains. Further, if the relaxation rate LL (%) is 15 or more, a great stress may be applied to the axial shift of the slow axis. In this case, there is a case where the slow axis that is convex in the shape of the bow in the traveling direction is forced too much, and a concave slow axis in the direction of travel is generated. Further, if the stress is too large, that is, if the relaxation is greatly applied, there is a possibility that a film surface abnormality may occur.

  In the present invention, the maximum axial deviation in the MD direction is controlled by adjusting the difference in the length of the tenter chain, and the axial deviation in the TD direction is controlled by stretching and relaxing the wet film in the tenter dryer. Can be adjusted. In this way, it is possible to control the axial misalignment in both directions to 2 degrees or less, and a polymer film having excellent optical isotropy can be obtained. Therefore, the polymer film according to the present invention can be preferably used for an optical film.

  In the solution casting method of the present invention, when casting dopes, two or more kinds of dopes can be simultaneously laminated and co-cast or sequentially laminated and co-cast. When performing simultaneous lamination and co-casting, a casting die to which a feed block is attached may be used, or a multi-manifold casting die may be used. It is preferable that the thickness of the layer on the air surface side and / or the thickness of the layer on the support surface side is 0.5% to 30% in the total film thickness of the film composed of multiple layers by co-casting. . Furthermore, when performing simultaneous lamination co-casting, it is preferable that the high-viscosity dope is wrapped with the low-viscosity dope when the dope is cast from the die slit to the support. Moreover, when performing simultaneous lamination | stacking co-casting, when casting dope from a die slit to a support body, it is preferable that internal dope is enclosed with dope with a larger composition ratio of alcohol than the dope.

  Solvent recovery method from casting die in casting, decompression chamber, support structure, etc., co-casting, peeling method, stretching process, drying conditions, handling method, curl, winding method after flattening The film collection method is described in detail in paragraphs [0610] to [0842] of Japanese Patent Application No. 2003-319673, and these descriptions can also be applied to the present invention.

[Performance / Measurement method]
The properties of the cellulose ester film wound up and the measuring method thereof are described in detail from paragraphs [0113] to [0140] of Japanese Patent Application No. 2003-319673, and these descriptions can also be applied to the present invention. .

[surface treatment]
It is preferable that at least one surface of the cellulose ester film is surface-treated. The surface treatment is preferably at least one of vacuum glow discharge treatment, atmospheric pressure plasma discharge treatment, ultraviolet irradiation treatment, corona discharge treatment, flame treatment, acid treatment or alkali treatment.

[Functional layer]
At least one surface of the cellulose ester film may be undercoated. Furthermore, it can also be used as a functional material provided with another functional layer using the cellulose ester film as a base film. The functional layer is preferably provided with at least one layer selected from an antistatic layer, a cured resin layer, an antireflection layer, an easy adhesion layer, an antiglare layer and an optical compensation layer.

The functional layers preferably contain at least one surfactant 0.1mg / m ² ~1000mg / m ² containing. Further, the functional layers preferably contain at least one sort of plasticizers in the 0.1mg / m ² ~1000mg / m ² containing. Further, the functional layers preferably contain at least one sort of matting agents in the 0.1mg / m ² ~1000mg / m ² containing. The functional layers preferably contain at least one sort of antistatic agents ^{1mg / m 3 ~1000mg / m 3} . In addition to the above, the method for applying a surface-treated functional layer for realizing various functions and properties on the cellulose ester film is described in detail in paragraphs [0843] to [1079] of Japanese Patent Application No. 2003-319673. , Including methods. These are also applicable to the present invention.

  The cellulose ester film is particularly useful as a polarizing plate protective film. Two polarizing plates to which a cellulose ester film is bonded are usually bonded to a liquid crystal layer to produce a liquid crystal display device. However, this arrangement may be at any position. Japanese Patent Application No. 2003-319673 describes in detail TN type, STN type, VA type, OCB type, reflective type, and other examples of liquid crystal display devices. This method can also be applied to the present invention. The application also describes a cellulose ester film provided with an optically anisotropic layer and a cellulose ester film provided with antireflection and antiglare functions. Furthermore, the use as an optical compensation film is also described as a biaxial cellulose-ester film which gives moderate optical performance. This can also be used as a polarizing plate protective film. These descriptions are also applicable to the present invention. Details are described in paragraphs [1080] to [1252] of Japanese Patent Application No. 2003-319673.

  Moreover, the cellulose triacetate film (TAC film) excellent in an optical characteristic can be obtained with the manufacturing method of this invention. The TAC film can be used as a polarizing plate protective film or a base film for a photographic photosensitive material. Further, it can be used as an optical compensation film for improving the viewing angle dependency of a liquid crystal display device for television. In particular, it is effective for applications that also serve as a protective film for a polarizing plate. Therefore, it is used not only in the conventional TN mode but also in the IPS mode, OCB mode, VA mode, and the like. Moreover, you may comprise a polarizing plate using the said film for polarizing plate protective films.

  The present invention will be described in detail with reference to Example 1 and Example 2, but the present invention is not limited to these embodiments.

  In Example 1, the description will be made in detail in Experiment 1 according to the present invention. For Experiments 2 to 8, the experimental conditions and experimental results are shown in Table 1.

(Preparation of raw material dope)
Cellulose triacetate (substitution degree 2.8) 89.3% by weight
Triphenyl phosphate 7.1% by weight
Biphenyl diphenyl phosphate 3.6% by weight
87% by weight of dichloromethane with respect to 100 parts by weight of solid content
Methanol 13% by weight
A mixed solvent as described above was appropriately added, and dissolved by stirring to prepare a raw material dope 16. The solid content concentration of the completed raw material dope was 19.0% by weight. The raw material dope thus prepared was filtered.

(Preparation of additive solution)
57 20.0% by weight
Raw material dope 13.9% by weight
The additive liquid 12 was prepared by mixing at the above ratio and performing filtration.
Chemical formula 57 represents the following compound (N, N′-di-m-tolyl-N ″ -p-methoxyphenyl-1,3,5-triazine-2
, 4,6-triamine). The addition amount of Chemical Formula 57 was adjusted so that the ratio (PHR) to 100% by weight of TAC was 5.55.

(Preparation of matting agent solution)
Silica particles (Japan Aerosil R972) 2.0% by weight
Raw material dope 15.6% by weight
Dichloromethane 76.1% by weight
Methanol 11.3 wt%
Mixing at the above ratio, dispersing with an attritor and filtering to prepare a matting agent solution.

  The matting agent solution 14 was mixed with the additive solution 12 using the static mixer 20, and the mixed solution of the additive solution 12 and the matting agent solution 14 was added to the raw material dope 16 and mixed with the static mixer 21.

  A casting die 30 having a width of 1.8 m was used. Further, casting was performed by adjusting the flow rate of the dope from the casting die 30 so that the thickness of the film product was 80 μm, the casting width was 1700 mm. In order to adjust the dope temperature to 36 ° C., a jacket (not shown) was provided on the casting die, and a heat transfer medium (water) having an inlet temperature of 36 ° C. was supplied into the jacket.

The casting die 30 and the piping were kept at 36 ° C. during film formation. The casting die 30 was a coat hanger type. Thickness adjusting bolts with a 20 mm pitch were used. The thickness difference between two arbitrary points 50 mm apart in the film excluding the casting edge portion 20 mm was within 1 μm, and the largest difference in the width direction thickness was adjusted to 3 μm / m or less. The thickness of the film was adjusted to be ± 1.5% or less.

  A decompression chamber 40 for decompressing was installed on the primary side of the casting die 30. The pressure reduction degree of the pressure reduction chamber 40 is such that a pressure difference of 1 Pa to 5000 Pa is generated before and after the casting bead, and can be adjusted according to the casting speed. The temperature of the decompression chamber 40 was also adjusted. Labyrinth packing (not shown) was provided at the rear part before and after the casting bead. Moreover, the opening part was provided in both ends. Furthermore, in order to adjust the disturbance of both edges of the casting bead, the one to which an edge suction device (not shown) is attached was used.

The material of the casting die 30 is a precipitation hardening type stainless steel or a two-layer stainless steel, and a material having a thermal expansion coefficient of 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less. A material having substantially the same corrosion resistance was used. In addition, a corrosion-resistant material that does not cause pitting (opening) at the gas-liquid interface even when immersed in a mixed solution of dichloromethane, methanol, and water for 3 months was used. The finishing accuracy of the wetted surface of the casting die 30 is 1 μm or less in terms of surface roughness, the straightness is 1 μm / m or less in any direction, and the slit clearance is automatically adjusted from 0.5 mm to 3.5 mm. What was possible was used. In this example, the measurement was performed at 1.5 mm. About the corner | angular part of the liquid-contact part of a die lip tip, it processed so that R might be 50 micrometers or less over the slit full width. The shear rate inside the die was in the range of 1 (1 / sec) to 5000 (1 / sec).

In addition, a lip tip of the casting die 30 was provided with a cured film. Means for providing a cured film include ceramic coating, hard chrome plating, nitriding treatment, and the like. When ceramics are used as the cured film, those that can be ground, have low porosity, are not brittle, have good corrosion resistance, have good adhesion to the casting die, and have no adhesion to the dope are preferable. Specific examples include tungsten carbide, Al ₂ O ₃ , TiN, Cr ₂ O _3, and tungsten carbide is particularly preferable. In this example, a tungsten carbide coating formed by a thermal spraying method was used.

  Further, in order to prevent the dope flowing out from the slit end of the casting die 30 from locally drying and solidifying, a mixed solvent (87 parts by weight of dichloromethane and 13 parts by weight of acetone) which is a solvent for solubilizing the dope is used. It was supplied at 0.5 ml / min on one side to the bead end and the slit gas-liquid interface. The pulsation rate of the pump supplying this liquid was 5% or less. Further, the pressure on the back surface of the bead was reduced by 150 Pa by the decompression chamber 40. A jacket (not shown) was attached to keep the temperature of the decompression chamber 40 constant. A heat transfer medium adjusted to 40 ° C. was supplied into the jacket. The edge suction air volume that can be adjusted in the range of 1 L / min to 100 L / min was used, and in this example, it was appropriately adjusted in the range of 30 L / min to 40 L / min.

A stainless steel endless band having a width of 2.0 m and a length of 70 m was used as the casting band 33 as a support. The casting band 33 was 1.5 mm thick and polished so that the surface roughness was 0.05 μm or less. The material was made of SUS316 and had sufficient corrosion resistance and strength. The thickness unevenness of the entire casting band 33 was 0.5% or less. The casting band 33 was driven by two rotating rollers 31 and 32. At this time, the tension of the casting band 33 is adjusted to 1.0 × 10 ⁴ kg / m, and the relative speed difference between the casting band 33 and the rotary rollers 31 and 32 is adjusted to 0.01 m / min or less. did. Moreover, the speed fluctuation of the casting band 33 was 0.5% or less. Further, both ends of the casting band 33 were detected and controlled so that the meandering in the width direction of one rotation was limited to 1.5 mm or less. Further, the positional fluctuation in the vertical direction between the die lip tip and the casting band 33 immediately below the casting die 30 was set to 200 μm or less.

As the rotating rollers 31 and 32, those capable of feeding a heat transfer medium therein were used so that the temperature of the casting band 33 could be adjusted. A heat transfer medium (water) at 20 ° C. was passed through the rotary roller 31 on the casting die side, and a heat transfer medium (water) at 40 ° C. was passed through the other rotary roller 32. The surface temperature of the central part of the casting band immediately before casting was 15 ° C., and the temperature difference between both ends was 6 ° C. or less. The casting band 33 preferably has no surface defects, has no pinholes of 30 μm or more, has no pinholes of 10 μm to 30 μm, 1 pin / m ² or less, and has 2 pinholes of 10 μm or less. What was ² or less was used.

  The temperature of the casting chamber 35 was kept at 35 ° C. The casting film 39 formed from the dope cast on the casting band 33 was first dried by sending parallel-flow drying air. The temperature of the drying air was blown from the air blowing ports 41, 42, and 43 so that the upstream side of the upper part of the casting band was 135 ° C, the downstream side was 140 ° C, and the lower part of the casting band was 65 ° C. The saturation temperature of each drying wind was around -3 ° C. The film was peeled off from the casting band 33 as a wet film 46. In order to suppress the peeling failure, the peeling speed (peeling roller draw) was set to 100.5% with respect to the casting band speed. The solvent gas generated by drying was condensed and liquefied by a condenser 37 and recovered by a recovery device 38. The drying air from which the solvent was removed was heated again and reused as drying air. At that time, the water content in the solvent was adjusted to 0.5% or less and reused. The wet film 46 was conveyed through the five rollers of the cross section 50 and sent to the tenter dryer 60. At this time, dry air of 70 ° C. was blown from the blower 51.

  A tenter dryer 60 having the form shown in FIG. 2 was used. The length L (mm) of the tenter chains 82 and 83 is 60 m, and the number Nu (pieces) of the links 100 and 101 of the tenter chains 82 and 83 is 800. In this case, the inter-link distance L1 (mm) was adjusted to 100 mm. The driven sprockets 86 and 87 were displaced by the shift mechanisms 93 and 94 so that the difference in length between the tenter chains 82 and 83 (hereinafter referred to as the maximum difference in elongation) was 2 mm or less.

  The film 61 was opened from the tenter dryer 60. In the tenter dryer 60, all hot air at 140 ° C. is adjusted in advance so that the wind speed in the width direction is constant, and the normal direction of the film (on the film plane) by an air supply nozzle (not shown) arranged intermittently. Sprayed from a direction perpendicular to the surface).

  Then, the ear-cleaving device 62 cuts the ears at both ends within 30 seconds from the tenter type dryer outlet. Before drying at a high temperature in a drying chamber 65 described later, the film 61 was preheated in a predrying chamber (not shown) to which 100 ° C. drying air was supplied.

  The film 61 was dried at a high temperature in the drying chamber 65. The first half was dried with hot air at 120 ° C. and the second half with 130 ° C., and the excess edge was cut off again. The conveying tension of the film 61 in the drying chamber with the roller 64 was 100 N / width, and the film was dried for about 30 minutes until the residual solvent amount finally became less than 0.2% by weight. The material of the roller 64 was made of aluminum or carbon steel, and the surface was plated with hard chrome. As the surface shape of the roller 64, a flat one and a mat processed by blasting were used. All the vibrations due to the rotation of the roller 64 were 50 μm or less. The roller deflection at a tension of 100 N / width was selected to be 0.5 mm or less.

  In the solution casting method, various steps such as a drying step and a side edge cutting and removing step are performed before the film (polymer film) peeled off from the support is wound up. In each of these processes or between each process, the film is mainly supported or conveyed by a roller. These rollers include a driving roller and a non-driving roller, and the non-driving roller is mainly used for determining a film conveyance path and improving conveyance stability.

  On the other hand, the drive roller is used to transmit drive to the film and convey it downstream, and a suction roller is usually used. In film transport in film formation, separation of transport tension may be necessary within each process such as casting process, stripping process, drying process, winding process, etc., and in that case, suction Separation of conveyance tension is achieved by applying a driving force to the film by a roller. This suction roller has a large number of air suction holes on the peripheral surface of the roller for adsorbing and transporting the film to itself.

  When a suction roller is used, the film is more easily deformed than a non-driven roller because a complex force whose directionality cannot be specified acts on the film. The film is also deformed by a difference in tension before and after the conveyance applied to the film. Furthermore, a large number of air suction holes are formed on the peripheral surface of the suction roller. If the film slips or contracts or deforms when the film is in contact with the edge of the suction hole, There are fine scratches.

  The driving roller used in the transporting process is a roller whose peripheral surface is previously cured by nitriding treatment, cured chrome plating, or quenching treatment. The surface hardness of the circumferential surface is 500 to 2000 in terms of Vickers hardness. Or less, more preferably 800 or more and 1200 or less.

  The drive roller used is a suction roller, and this suction roller has a large number of air suction holes on its peripheral surface. At this time, the surface roughness Ry of the peripheral surface of the suction roller is preferably 0.3 μm or more and 1.0 μm or less, more preferably 0.5 μm or more and 0.8 μm or less. As for the surface roughness Ry of the peripheral surface, the surface roughness of the smooth portion having no hole in the roller is the peripheral surface roughness. The hole diameter is preferably 1 mm or more and 6 mm or less, more preferably 2 mm or more and 4 mm or less, and the chamfering amount of the hole is preferably 2% or more and 20% or less of the hole diameter.

  When using the suction roller, it is preferable to control the peripheral surface temperature, and therefore, it is preferable to have at least one temperature adjusting device for one suction roller. It is preferable to form the film while making the peripheral surface temperature of the roller higher than the film temperature immediately before contacting the suction roller. These rollers are described in detail in paragraphs [0005] to [0007] and [0014] to [0016] of Japanese Patent Application No. 2004-160159, and can also be applied to the present invention.

  The solvent gas contained in the drying air was adsorbed and recovered using an adsorption recovery device 66. The adsorbent was activated carbon, and desorption was performed using dry air. The recovered solvent was adjusted to a water content of 0.3% by weight or less and reused as a dope preparation solvent. Since the drying air contains a plasticizer, an ultraviolet absorber, and other high-boiling compounds in addition to the solvent gas, these were removed by a cooling machine and a pre-adsorber to be cooled and removed, and used for recycling. And adsorption / desorption conditions were set so that VOC (volatile organic solvent) in the outdoor exhaust gas would be 10 ppm or less. Both ends of the film 61 were cut off, and further, knurling was performed on both ends of the film 61 with a knurling roller 69. The knurling was applied by embossing from one side, the knurling width was 10 mm, and the pressing pressure was set so that the maximum height was 12 μm higher than the average thickness on average.

  Then, the film 61 was conveyed to the winding chamber 70. The winding chamber 70 was kept at a room temperature of 28 ° C. and a humidity of 70%. Furthermore, an ion wind static elimination device (not shown) was also installed so that the film charging voltage was −1.5 kV to +1.5 kV. The product width of the film 61 (thickness 80 μm) 61 thus obtained was 1340 mm. The diameter of the winding roller 71 was 169 mm. The winding start tension was 250 N / width, and the total winding length was 2640 m, with a tension pattern such that the winding end was 220 N / width. The period during winding was 400 m, and the oscillating width was ± 5 mm. The temperature of the film at the time of winding was 25 ° C., the water content was 1.4% by weight, and the residual solvent amount was less than 0.2% by weight. The content of silica particles in the film was 0.13% by weight.

A sample was accurately taken with a cutting plotter at a position 50 mm from one end of the obtained film, a position 50 mm from the opposite end, and the center of the film, and the maximum axial displacement in the longitudinal direction was measured with KOBRA-21DH manufactured by Oji Scientific Instruments. The Re value at 632.8 nm was measured. The maximum axis shift of the traveling axis in the longitudinal direction was 0.3 degree, and the Re value was 1 nm when the Re value was an average value in the width direction. Moreover, the axial shift of the slow axis perpendicular to the longitudinal direction of the film was 0.5 degree.

  In Experiment 1, the maximum difference in elongation was 2 mm. The maximum difference in elongation was evaluated as ◯ when 4 mm or less and 0.0001 × L were satisfied, △ when only 0.0001 × L was satisfied, and × when none was satisfied. In Experiment 1, it was ○. When the maximum clearance difference was 4 / Nu (mm) or less, it was evaluated as ◯, and when it exceeded that, it was evaluated as x. In Experiment 1, it was ○. Axial misalignment is less than 2 degrees, and more than 2 degrees is x. In Experiment 1, it was ○. From the above and the result of the maximum axial deviation, the overall evaluation of Experiment 1 was ○ (very good).

  In Experiment 2, the experiment was performed under the same conditions as Experiment 1 except that the shift mechanism was not used (×). In Experiment 3, the experiment was performed under the same conditions as Experiment 2 except that the number of links Nu was 500. In Experiment 4, the experiment was performed under the same conditions as Experiment 2 except that the number of links Nu was 3000. In Experiment 5, the experiment was performed under the same conditions as Experiment 2 except that a tenter chain having a length L (m) of 100 m was used. In Experiment 6, an experiment was performed under the same conditions as in Experiment 2 except that a tenter chain with a length L (m) of 100 m was used and the number of links Nu was 500.

  From Table 1, the overall evaluation of the films obtained in Experiment 3 and Experiment 6 in which both the maximum elongation difference evaluation and the maximum clearance evaluation were ◯ were extremely excellent (◯), and the maximum axial displacement was less than 2 degrees. And was excellent. Further, the overall evaluation of the film obtained from Experiment 5 in which only 0.0001 × L was satisfied in the maximum elongation difference evaluation was excellent (Δ), but the axial misalignment was slightly large at 3 degrees. Furthermore, the overall evaluation of the films obtained in Experiment 2 and Experiment 4 in which both the maximum elongation difference evaluation and the maximum clearance evaluation were x was poor (x), and the maximum longitudinal axis deviation was also 5 or 6 degrees. It was big.

  The film formed in Experiment 1 was saponified and then attached to one side of the polarizing film, and Fujitaku Fujitac (registered trademark; 80 μm) was attached to the opposite side to produce a polarizing plate. When the produced polarizing plate was applied in place of the polarizing plate and the retardation film of the VA type (vertical alignment type) liquid crystal display device, good display was obtained in both cases.

  In Example 2, Experiment 7 was performed under the same conditions as Experiment 1 of Example 1 except that the tenter dryer 60 was changed to a tenter dryer 120 capable of relaxing stretching.

  The wet film 46 sent to the tenter dryer 120 was conveyed at the inlet 121 without changing the width (see FIG. 5). The residual volatile content at the stretching start position 121a was 38.0% by weight. The biting width L2 (mm) was 1465 mm. The wet film 46 was stretched by the stretching portion 122, and the maximum stretching width L3 (mm) was 1841 mm. The stretching speed during stretching was 0.8% / min. Thereafter, the wet film 46 (which may be regarded as the film 125) is relaxed by the relaxing portion 123, and the separation width L4 (mm) is set to 1765 mm. The relaxation rate was reduced at 0.7% / min. The difference in volatile content (based on dryness) was 18.0% by weight. In this case, the maximum stretching ratio Lmax (%) was 25.7%, the separation stretching ratio Lout (%) was 20.5%, and the relaxation ratio L (%) was 5.2%. After passing through the exit portion 124 conveyed at a constant width, the film was opened from the tenter dryer 120 to form a film 125.

  The axial deviation in the longitudinal direction and the width direction and the Re value at 632.8 nm were measured under the same conditions as in Experiment 1. The maximum axis shift of the traveling axis in the longitudinal direction was 0.5 degree, and the Re value was 1 nm when the Re value was an average value in the width direction. Moreover, the axial shift of the slow axis perpendicular to the longitudinal direction of the film was 0.5 degree.

It is the schematic of the film manufacturing line used for the solution casting method of this invention. It is a schematic plan view of the tenter type dryer according to the present invention. It is a principal part enlarged view of FIG. It is a figure which shows the correlation with a tenter chain movement distance and an axial shift. It is a schematic plan view of a tenter type dryer according to another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Film production line 60 Tenter type dryer 61 Film 82, 83 Tenter chain 84, 85 Driving sprocket 86, 87 Drive sprocket 91, 92 Sensor 93, 94 Shift mechanism 95 Drying zone 100, 101 Link 120 Tenter type dryer L Tenter chain Length L1 Link distance

Claims (24)

In a polymer film produced by a solution casting method using a tenter dryer equipped with two sets of tenter chains having a length of L (mm),
A polymer film produced by adjusting a difference in elongation of tenter chains on both sides of the tenter chain to 0.0001 × L (mm) or less. In a polymer film produced by a solution casting method using a tenter dryer equipped with two sets of tenter chains,
A polymer film manufactured by adjusting a difference in elongation of the tenter chain to 4 mm or less. The maximum axis deviation of the traveling axis in the longitudinal direction of the film is
The polymer film according to claim 1 or 2, wherein the tenter chain is less than 2.0 degrees when it rotates once. The tenter chain is wound around two sprockets,
Detecting the movement of the position of the sprocket due to the elongation of the tenter chain;
Displacing at least one of the sprockets,
The polymer film according to any one of claims 1 to 3, wherein a difference in elongation of the tenter chain is adjusted. The tenter chain is formed of Nu links,
The polymer film according to any one of claims 1 to 4, wherein a clearance difference between the links is adjusted to 4 mm / Nu or less. A slow axis that is a direction perpendicular to the transport direction of the film in any region of the film;
The slow axis of all regions adjacent to the arbitrary region;
The polymer film according to any one of claims 1 to 5, wherein an axial misalignment is less than 2.0 degrees.   The polymer film according to claim 6, wherein the area is an area of 50 mm in each of the longitudinal direction and the width direction of the film. When drying the film with the tenter dryer,
The polymer film according to any one of claims 1 to 7, wherein the polymer film is relaxed in the width direction of the film after being stretched in the width direction of the film. When drying the film with the tenter dryer,
The polymer film according to any one of claims 1 to 8, wherein the drying temperature of the film is maintained at substantially the same temperature in a range of 50 ° C to 180 ° C.   The polymer film according to claim 1, wherein the polymer film is an optical film.   The polymer film according to claim 1, wherein the polymer film is a cellulose ester film.   The polymer film according to any one of claims 1 to 11, wherein the polymer film is attached to at least one surface of a polarizing film.   The polymer film according to any one of claims 1 to 12, wherein the polymer film is attached to at least one surface of a polarizing plate constituting a liquid crystal display device. A dope containing a polymer and a solvent is cast on a support, and then peeled off from the support as a film. The film is dried with a tenter dryer having two sets of tenter chains each having a length L (mm). In the solution casting method to
A solution casting method, wherein a difference in elongation between tenter chains on both sides of the tenter chain is adjusted to 0.0001 × L (mm) or less. In a solution casting method in which a dope containing a polymer and a solvent is cast on a support and then peeled off from the support as a film, and the film is dried with a tenter dryer provided with two sets of tenter chains.
A solution casting method characterized by adjusting a difference in elongation of the tenter chain to 4 mm or less. The tenter chain is wound around two sprockets,
Detecting the movement of the position of the sprocket due to the elongation of the tenter chain;
Displace at least one of the sprockets based on the detection result,
16. The solution casting method according to claim 14, wherein a difference in elongation of the tenter chain is adjusted. The tenter chain is formed of Nu links,
The solution casting method according to any one of claims 14 to 16, wherein a clearance difference between the links is adjusted to 4 mm / Nu or less. When drying the film with the tenter dryer,
The solution casting method according to any one of claims 14 to 17, wherein the film is relaxed in the width direction of the film after being stretched in the width direction of the film. When drying the film with the tenter dryer,
The solution casting method according to any one of claims 14 to 18, wherein the drying temperature of the film is maintained at substantially the same temperature in a range of 50 ° C or higher and 180 ° C or lower.   The solution casting method according to any one of claims 14 to 19, wherein the polymer is a cellulose ester. A plurality of gripping means for gripping both edges of the film, two sets of tenter chains to which the plurality of gripping means are attached and having a length of L (mm), and two pieces around which the respective tenter chains are wound A tenter type dryer that includes the sprocket and drying means for drying the film, and grips and dries the film with the gripping means.
Detecting means for detecting movement of the position of the sprocket due to the elongation of the tenter chain;
A shift mechanism for adjusting the position of the sprocket based on the detection result,
A tenter dryer, wherein a difference in elongation between tenter chains on both sides of the tenter chain is adjusted to 0.0001 × L (mm) or less. A plurality of gripping means for gripping both edges of the film, two sets of tenter chains to which the plurality of gripping means are attached, two sprockets around which the respective tenter chains are wound, and the film A tenter dryer comprising: drying means for drying; and gripping and drying the film with the gripping means.
Detecting means for detecting movement of the position of the sprocket due to the elongation of the tenter chain;
A shift mechanism for adjusting the position of the sprocket based on the detection result,
A tenter dryer, wherein a difference in elongation of the tenter chain is adjusted to 4 mm or less.   The tenter dryer according to claim 21 or 22, wherein the tenter chain passes through a path that relaxes after the film is stretched. The tenter dryer according to any one of claims 21 to 23, wherein the drying means maintains a drying temperature of the film at substantially the same temperature in a range of 50 ° C to 180 ° C.

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