JP4920222B2 - Dope filtration apparatus, filtration method, and solution casting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a film suppressing admixture of a foreign matter of metal fiber. <P>SOLUTION: A raw material dope 36 containing TAC (cellulose triacetate) and a plasticizer is filtered by a filtration device 57. In the filtration device 57, a filter medium 59 composed of a first layer 59a, a second layer 59b and a third layer 59c in the order of the flow of the raw material dope 36 is arranged. An average diameter of the sintered metal fibers of the first layer 59a is 8&mu;m, that of the second layer 59b is 4&mu;m and that of the third layer 59c is 20&mu;m to constitute the layers 59a-59c. The filter 59 is roasted 2 hours at 400&deg;C and reused. Breakages from the sintered metal fibers in the first and second layers 59a and 59b are filtrated in the third layer 59c to prevent admixture of a foreign matter of a metal fiber in the dope. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a dope filtration method and a solution casting method, and more particularly, to a dope filtration method and a solution casting method including cellulose acylate and a solvent.

  A TAC film formed from cellulose acylate, particularly cellulose triacetate (TAC) having an average degree of acetylation of 57.5% to 62.5% is used for a film of a photographic photosensitive material because of its toughness and flame retardancy. It is used as a support. Further, since the TAC film is excellent in optical isotropy, it is used for a polarizing plate protective film, an optical compensation film (for example, a viewing angle widening film, etc.) of a liquid crystal display device whose market is expanding in recent years. Yes.

  The TAC film is usually produced by a solution casting method. The solution casting method can produce a film having excellent optical properties as compared with other production methods such as a melt casting method. In the solution casting method, a polymer is first dissolved in a mixed solvent containing dichloromethane or methyl acetate as a main solvent to prepare a polymer solution (hereinafter referred to as a dope). Next, the dope is cast on a support from a casting die to form a casting film. After the cast film becomes self-supporting on the support, it is peeled off from the support as a film (hereinafter referred to as a wet film), dried and then wound up as a film.

It is known to perform filtration using a filter material (filter) made of sintered metal fibers in order to remove foreign substances in the dope used for solution casting or spinning (see, for example, Patent Documents 1 to 4). ). This is because the sintered metal fiber filter medium has a firm structure and can withstand high-pressure loss, and is therefore suitable for filtering a dope having a high viscosity. The sintered metal fiber filter medium is manufactured by intertwining metal fibers having arbitrary diameters and lengths into a felt shape, and high-temperature treatment in a non-oxidizing atmosphere to weld the fibers together (for example, Patent Documents 5 to 5). 7). In this sintered metal fiber filter medium, the filtration accuracy can be adjusted relatively easily by arbitrarily changing the diameter of the metal fiber as the raw material. Therefore, it is suitable for dope filtration for manufacturing various films used in a liquid crystal display device that is required to have few foreign matters. The sintered metal fiber filter medium can be regenerated and reused by roasting after clogging. For this reason, it is excellent because the waste filter medium does not become waste. The roasting reproduction method is described in Patent Document 8, for example.
JP-A-7-009584 JP 7-124421 A JP 2001-213974 A JP 2002-363342 A JP-A-60-103103 Japanese Patent Publication No.3-333370 Japanese Patent Publication No. 3-39727 Japanese Patent Publication No. 63-51727

  However, when the sintered metal fiber filter medium is regenerated and used, the metal fiber may be damaged by roasting (hereinafter referred to as a damaged article) and may be separated from the filter medium and mixed into the dope. This is because the metal fiber deteriorates and breaks due to roasting. Therefore, when the dope filtered with such a filter medium is used for the production of a film for optical use, for example, a damaged material is mixed into the film, resulting in a product defect. It is possible to reduce the inclusion of damaged materials into the dope by thoroughly washing before and after roasting, removing clogs remaining on the metal fibers as much as possible, and relaxing the roasting conditions. However, it is difficult to eliminate them. For this reason, in producing a film having excellent optical characteristics, foreign matter resulting from mixing of a filter medium breakage into the dope has become a problem. In particular, in the case of using a sintered metal fiber filter medium, in order to improve the filtration accuracy, generally, the diameter of the metal fiber used for the production of the filter medium is reduced, so that this breakage is more likely to occur. For this reason, generation | occurrence | production of a metal fiber broken material is an obstacle at the time of improving the filtration precision and improving the foreign material in a product film.

  An object of the present invention is to provide a dope filtration method and a solution film formation method using the filtered dope so as to suppress the inclusion of a broken material generated from a sintered metal fiber filter medium into the dope. To do.

The present invention provides a filter device that includes a filter medium that is roasted and reused, and that filters a dope containing cellulose acylate and a chlorinated solvent, and includes a sintered metal fiber having an average diameter of 4 μm to 8 μm. The filter medium comprising a filter and a second filter made of sintered metal fibers having an average diameter of 15 μm or more and 60 μm or less and arranged on the downstream side of the first filter is provided inside the filter device body. It is structured as a feature. It is preferable that the filter medium has a third filter made of sintered metal fibers having an average diameter of 8 μm or more and 30 μm or less and arranged on the upstream side of the first filter. The second filter preferably has a larger average diameter of sintered metal fibers than the third filter. The filter medium is preferably pleated. The present invention also relates to a dope filtration method in which a dope containing cellulose acylate and a chlorinated solvent is filtered by a filtration device equipped with a filter medium that is roasted and reused, and an average diameter of 4 μm or more and 8 μm or less. An apparatus for filtering the filter medium, comprising: a first filter made of a bonded metal fiber; and a second filter made of a sintered metal fiber having an average diameter of 15 μm or more and 60 μm or less and arranged on the downstream side of the first filter. The dope is sent to the filtering device main body of the filtering device provided in the main body and filtered. It is preferable that the filter medium has a third filter made of sintered metal fibers having an average diameter of 8 μm or more and 30 μm or less and arranged on the upstream side of the first filter. The second filter preferably has a larger average diameter of sintered metal fibers than the third filter. The filter medium is preferably pleated. The filter device main body preferably includes the filter medium in which the second filter is arranged inside the cylindrical first filter. The second filter is preferably a filter disposed on the most downstream side of the filter medium.

Further, a filter medium was roasted at a temperature of 350 ° C. or higher 500 ° C. or less, arbitrary preferred to reuse.

The chlorinated solvent means dichloromethane or the like in which hydrogen bonded to an aliphatic hydrocarbon is replaced with chlorine. The sintered metal fiber is preferably formed from a material containing at least one of austenitic stainless steel, martensitic stainless steel, ferrite stainless steel, or a composite stainless steel thereof.

Further, the present invention is a solution film-forming method in which a dope is filtered by a filtration device equipped with a filter material that is roasted and reused , and then cast, and is made of sintered metal fibers having an average diameter of 4 μm to 8 μm. The filter medium comprising a first filter and a second filter made of sintered metal fibers having an average diameter of 15 μm or more and 60 μm or less and arranged on the downstream side of the first filter is provided inside the filter device body. Further, a dope containing cellulose acylate and a chlorinated solvent is sent to the filtering device main body of the filtering device, filtered, and the filtered dope is cast on a support, peeled off, dried, and then dried. It is comprised including the solution casting method characterized by manufacturing this. The cellulose acylate is preferably cellulose triacetate.

  According to the liquid filtration method of the present invention, the first filter medium made of sintered metal fibers, and the average diameter larger than the average diameter of the sintered metal fibers of the first filter medium, the average diameter is 15 μm or more and 60 μm. Since it has the 2nd filter medium which consists of the following sintered metal fibers, and these 1st and 2nd filter media were arranged in order in the flow direction of the dope, dope with the 1st filter medium which consists of sintered metal fibers Filtering can be performed with a desired filtration accuracy, and contamination with foreign matters can be suppressed. In addition, since a sintered metal fiber filter medium is used, filtration of a highly viscous liquid and high-speed filtration with an increased liquid feed flow rate are possible, and the filtration efficiency is improved.

  Moreover, the damaged material of the sintered metal fiber can be filtered by the second filter medium, and the damaged material of the sintered metal fiber from the first filter material for filtering the dope with a desired filtration accuracy is mixed and discharged into the dope. It will not be done. Therefore, when performing solution film formation using this dope, mixing of a foreign material is prevented. Thereby, a film excellent in optical properties can be obtained.

  By making the average diameter of the sintered metal fibers of the first filter medium 4 μm or more and 8 μm or less, when a dope obtained by filtration is produced by a solution film forming method, foreign matter is less mixed and optical characteristics are excellent. Film is obtained.

  In addition, the sintered metal fiber can be roasted at a temperature of 350 ° C. or higher and reused to reduce the cost of the filter medium. When a chlorine-based solvent is used as the solvent and cellulose acylate is used as the polymer, a dope suitable for the solution casting method can be produced. By performing solution film formation using the dope, foreign matters in the dope are removed, so that a film having excellent optical characteristics can be obtained. Further, since the sintered metal fiber is formed to include at least one material selected from austenitic stainless steel, martensitic stainless steel, ferrite stainless steel, or a composite stainless steel thereof, it has excellent durability. Since it can be reused even if it is repeated, costs can be reduced.

As the cellulose acylate, 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 (1-a) to (1-c). Hereinafter, cellulose acylate satisfying the following formula is referred to as TAC.
2.5 ≦ A + B ≦ 3.0 (1-a)
0 ≦ A ≦ 3.0 (1-b)
0 ≦ B ≦ 2.9 (1-c)
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 that 90 mass% or more of TAC is a particle | grain of 0.1 mm-4 mm. In the present invention, the raw material polymer for the dope is not limited to TAC.

  Solvents for preparing the dope include aromatic hydrocarbons (eg, benzene, toluene, etc.), halogenated hydrocarbons (eg, dichloromethane, 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. One kind of alcohol having 1 to 5 carbon atoms in addition to dichloromethane from the viewpoint of physical properties such as solubility of TAC, peelability of cast film from the support, mechanical strength of the film, and optical properties of the film It is preferable to mix several kinds. 2 mass%-25 mass% are preferable with respect to the whole solvent, and, as for content of alcohol, 5 mass%-20 mass% are more preferable. Specific examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol and the like, 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. Ethers having 4 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and alcohols having 1 to 12 carbon atoms are preferably used. Usually, it is used as a mixed solvent in which these are mixed. For example, a mixed solvent of methyl acetate, acetone, ethanol, n-butanol and the like can be mentioned. Further, these ethers, ketones, esters and alcohols may have a cyclic structure. A compound having two or more of ether, ketone, ester, and alcohol (that is, —O—, —CO—, —COO—, —OH) can also be used as the solvent.

  Details of cellulose acylate are described in paragraphs [0140] to [0195] of JP-A-2005-104148. These descriptions are also applicable to the present invention. In addition, additives such as solvents and plasticizers, deterioration inhibitors, UV absorbers (UV agents), optical anisotropy control agents, retardation control agents, dyes, matting agents, release agents, release accelerators, The details are described in paragraphs [0196] to [0516] of JP-A-2005-104148.

  In order to make the characteristics of the film favorable, an additive may be added to the dope. Additives include plasticizers (for example, triphenyl phosphate, biphenyl diphenyl phosphate, dipentaerythritol hexaacetate, ditrimethylolpropane tetraacetate), ultraviolet absorbers (for example, oxybenzophenone compounds, benzotriazole compounds, etc.) ), Matting agents (for example, silicon dioxide fine particles), thickeners, oil gelling agents, retardation control agents (optical anisotropy control agents) and the like, but are not limited thereto. The additive may be added when the polymer is dissolved in a solvent, or may be mixed in-line with the prepared dope during solution film formation. Moreover, when adding an additive, only an additive may be added and the additive solution which dissolved the additive in the solvent may be added.

  A film obtained by adding a substance having an acid property (hereinafter referred to as an acid substance) in the dope is excellent in peelability. Examples of the acid substance include inorganic acids (eg, hydrochloric acid), organic acids (eg, phenol), organic carboxylic acids (eg, acetic acid, lactic acid), polyvalent organic carboxylic acids (eg, citric acid, tartaric acid, etc.) ), And polyvalent organic carboxylic acid derivatives, but are not limited thereto. The basic skeleton of the polyvalent organic carboxylic acid derivative is an aliphatic hydrocarbon type (for example, linear saturated, branched saturated, linear unsaturated, branched unsaturated, monocyclic, aromatic, condensed polycyclic, bridged ring Formulas, spiros, ring assemblies, terpenes, etc.), aromatic hydrocarbons (eg, aromatics, condensed polycyclics, etc.) and heterocyclics (eg, heterocycles, etc.), but are not limited thereto. It is not a thing. In order not to affect the optical properties of the film, the polymer is preferably contained in the range of 200 ppm to 800 ppm.

  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.

  An electron donating group is one having a Hammett σp value of 0 or less. Rev. , 91, 165 (1991) having a Hammett σp value of 0 or less is preferably applicable, and more preferably −0.85 to 0. 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 having 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). ). 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, or 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 the general formula (2-A), R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are respectively synonymous with those in the general formula (2), and The preferable range is also the same.

In 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, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group and the like can be 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 are synonymous with those in the general formula (2), and preferred ranges are also included. 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 R ¹ , R ² , R ⁴ and R ⁵ are all hydrogen atoms, X is preferably an alkyl group, an alkynyl group, an aryl group, an alkoxy group or an aryloxy group, more preferably an aryl group or an 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, an ethoxy 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, Alkoxycarbonyl group, an ethoxycarbonyl group, n- propoxycarbonyl group, 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 are synonymous with 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 ⁵ 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 general formula (2-E), R ² , R ⁴ and R ⁵ have the same meanings as those in general formula (2-D), and the preferred ranges are 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. Preferably represents a ^{group R} 4, ^{R 5} is represented by ^{-OR 13,} more preferably a ^{group R 4} is represented by ^{-OR 13.} 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.) It 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.) 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 diethyl 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 ° C to 150 ° C, more preferably 0 ° C to 100 ° C, still more preferably 0 ° C 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).

  FIG. 1 shows a raw material dope production line 10. In manufacturing the raw material dope (hereinafter also simply referred to as “dope”), first, the valve 12 connected to the solvent tank 11 is opened, and the solvent is sent to the dissolution tank 13. Next, the TAC contained in the hopper 14 is fed into the dissolution tank 13 while being measured. By opening / closing the valve 16, an additive solution (for example, a solution in which a plasticizer is dissolved) is sent from the additive tank 15 to the dissolution tank 13 by a necessary amount. In addition to the method of sending the additive as a solution, when the additive is liquid at room temperature, it is also possible to send the additive to the dissolution tank 13 in the liquid state. In addition, when the additive is solid, it can be fed into the dissolution tank 13 using a hopper. When a plurality of types of additives are added, a solution in which a plurality of types of additives are dissolved can be placed in the additive tank 15. It is also possible to put a solution in which an additive is dissolved in each of a plurality of additive tanks and send the solution to the dissolution tank 13 through independent pipes.

  In the above description, the order of putting into the dissolution tank 13 is the solvent, the TAC, and the additive. However, the order is not limited to this order. It is also possible to send a preferable amount of the solvent after sending the TAC to the dissolution tank 13 while measuring it. Further, it is not always necessary to add the additive to the dissolution tank 13 in advance, and it can be mixed with a mixture of TAC and a solvent (hereinafter, these mixtures are also referred to as dope) in a later step.

  The dissolution tank 13 includes a jacket 17 and a first stirring blade 19. The jacket 17 is formed so as to enclose the dissolution tank 13. A heat transfer medium is caused to flow in the jacket 17 to adjust the inside of the dissolution tank 13 to a constant temperature within a range of −10 ° C. to 55 ° C. The first stirring blade 19 is rotated by a motor 18 to stir the solvent, TAC, and additive in the dissolution tank 13. Furthermore, it is preferable that the second stirring blade 21 is attached to the dissolution tank 13. The second stirring blade 21 is rotated by the motor 20 to stir the solvent and the like. The first stirring blade 19 is preferably an anchor blade, and the second stirring blade 21 is preferably a dissolver type. By appropriately selecting and rotating the first stirring blade 19 and the second stirring blade 21, the swelling liquid 22 in which the TAC is swollen in the solvent can be obtained.

  The swelling liquid 22 is sent to the heating device 26 by the pump 25. The heating device 26 preferably uses a jacketed pipe, and preferably has a configuration capable of pressurizing the swelling liquid 22. The dope is obtained by dissolving TAC or the like in a solvent under heating or pressure heating conditions of the swelling liquid 22. In this case, it is preferable to perform a method of preparing the dope by heating the swelling liquid 22 to a constant temperature within the range of 50 ° C. to 120 ° C. (hereinafter referred to as a heating dissolution method). Moreover, the cooling dissolution method which cools the swelling liquid 22 to a fixed temperature within the range of -100 degreeC--30 degreeC can also be performed. TAC can be sufficiently dissolved in a solvent by appropriately selecting the heating dissolution method and the cooling dissolution method. After the temperature of the dope is set to about room temperature by the temperature controller 27, the dope is filtered by the filtering device 28 to remove impurities in the dope. It is preferable that the average pore diameter of the filter medium of the filter device 28 is 10 μm or less. The filtration flow rate is preferably 50 L / hr or more. The dope after filtration is put into the mixing tank 30 via the valve 29.

  By the way, the method of once preparing the swelling liquid 22 as described above and then using the swelling liquid 22 as a dope takes time as the concentration of TAC is increased, and there may be a problem in terms of cost. In that case, it is preferable to perform a concentration step of preparing a dope having a target concentration after preparing a dope having a concentration lower than the target TAC concentration. The dope filtered by the filtering device 28 is sent to the flash device 31 through the valve 29. A part of the solvent in the dope is evaporated in the flash device 31. The evaporated solvent is made into a liquid by a condenser (not shown) and then recovered by the recovery device 32. It is advantageous from the viewpoint of cost that the solvent is regenerated and reused as a solvent for dope preparation by the regenerator 33.

  The concentrated dope is extracted from the flash unit 31 using the pump 34. Furthermore, it is preferable to perform a bubble removal process for removing bubbles generated in the dope. Any known method may be applied to remove bubbles, for example, an ultrasonic irradiation method. Thereafter, the liquid is fed to the filtration device 35 to remove foreign matters. In addition, it is preferable that the temperature of dope exists in the range of 0 degreeC-200 degreeC in this case. By these methods, a dope having a TAC concentration of 5% by mass or more and 40% by mass or less can be manufactured. More preferably, the TAC concentration is from 15% by mass to 30% by mass, and most preferably from 17% by mass to 25% by mass. The concentration of the additive (mainly a plasticizer) is preferably in the range of 1% by mass to 20% by mass when the entire solid content in the dope is 100% by mass. The produced raw material dope 36 is stored in the mixing tank 30.

  [0517] of JP-A-2005-104148 regarding dope production methods such as dope raw materials, raw materials, additive dissolution and addition methods, filtration methods, and defoaming methods in a solution casting method for obtaining a TAC film. The [0616] paragraph is detailed from the paragraph. These descriptions are also applicable to the present invention.

  FIG. 2 shows a film production line 50. A stirring blade 38 that is rotated by a motor 37 is attached to the mixing tank 30. The raw material dope 36 is always made uniform by rotating the stirring blade 38.

  The raw material dope 36 is transferred to the stock tank 52 using the gear pump 51. After that, it is filtered by the first filtration device 54 using the pump 53 and then transferred to the stock tank 55. It is preferable to use a filter paper, filter cloth, non-woven fabric, diatomaceous earth, or the like as the filter medium of the first filtration device 54, and it is particularly preferable to use filter paper, filter cloth or a combination thereof.

Further, the filter medium of the first filtration device 54 may be any type of a membrane filter, a surface filter, and a depth filter. The filtration accuracy with these filter media is more preferably 5 μm or more and 50 μm or less. The absolute filtration accuracy is defined by JIS Z 8901. An outline of the measurement method will be described. A liquid to be filtered composed of glass beads (hereinafter referred to as beads) of test powders having different particle diameters and pure water is placed in a beaker and stirred with a stirrer. The filtrate to be filtrated is obtained by sucking the filtrate to be filtered in the beaker through the filter medium sample in a state of atmospheric pressure to −4 kPa with a vacuum pump. Observe the number of beads per unit volume contained in the filtrate to be filtered and the filtrate with a microscope, calculate the particle collection rate (the following formula), and calculate the absolute particle size when the particle collection rate is 95%. This is called filtration accuracy.
Particle collection rate (%) = (the number of beads in the filtrate in a unit volume−the number of beads in the filtrate in a unit volume) / (the number of beads in the filtrate in a unit volume) × 100

  If the absolute filtration accuracy of the first filtration device 54 is less than 5 μm, the filtration life becomes too short, and the productivity of the film may be deteriorated. On the other hand, if the absolute filtration accuracy exceeds 50 μm, there is a possibility that the removal of foreign matters that cause deterioration of film characteristics may be incomplete. In this case, it is not preferable because the filtration load of the second filtration device 57 in FIG.

  In the first filtration device 54, various insoluble matters resulting from the raw materials, foreign matters mixed from outside the packaging and the process are filtered in large amounts, and therefore it is generally difficult to recycle and reuse the filter medium. For this reason, non-metallic filter media such as the above-mentioned filter paper, filter cloth, non-woven fabric, and diatomaceous earth that can be disposed of at low cost are used as the filter media of the first filter device 54.

  The raw material dope 36 in the stock tank 55 is sent to the second filtration device 57 by the pump 56 and filtered. FIG. 3 shows a cross section of the second filtration device 57. A cylindrical filter medium 59 is provided in the cylindrical filter main body 58. The filter medium 59 is preferably made of sintered metal fibers formed from austenitic stainless steel, martensitic stainless steel, ferrite stainless steel, or a composite stainless steel thereof, particularly preferably formed from austenitic stainless steel. Is to use.

  By using sintered metal fibers made of stainless steel in this way, in the case of dope using a chlorinated solvent, the occurrence of filter media corrosion due to hydrochloric acid or the like is suppressed, and the generation of impurities due to corrosion is eliminated. Further, it is preferable to use a filter medium 59 formed by sintering fibers. In this case, the porosity is large and the pressure loss is extremely low compared to metal filter medium such as powder sintered filter medium and wire mesh filter medium. It will be small.

  The filter medium 59 is composed of a first layer 59a, a second layer 59b, and a third layer 59c in this order in the flow direction, and each of these layers 59a to 59c is formed by sintering the above metal fibers. The average diameter of the metal fibers used for the first layer 59a is 8 μm or more and 60 μm or less. The average diameter of the metal fibers used for the second layer 59b is 4 μm or more and 8 μm or less. The average diameter of the metal fibers used for the third layer 59c on the most downstream side is 15 μm or more and 60 μm or less. Preferably, the 1st layer 59a is 8 micrometers or more and 30 micrometers or less, and the 3rd layer 59c is 15 micrometers or more and 30 micrometers or less. By using a fiber having a fiber diameter within the above range, even if broken materials are generated due to roasting, the broken materials can be reliably captured by the third layer 59c.

  In the present invention, the number of layers of the filter medium 59 of the second filtration device 57 is not limited to three layers. Preferably they are 2 layers or more and 6 layers or less, More preferably, they are 2 layers or more and 5 layers or less, Most preferably, they are 2 layers or more and 4 layers or less. Moreover, it is preferable to use the thickness of each layer 0.2 mm or more and 1 mm or less. The overall thickness of the filter medium 59 after sintering each layer is preferably 0.6 mm or more and 1.5 mm or less. The absolute filtration accuracy of the filter medium 59 is preferably 1 μm or more and 50 μm or less, more preferably 3 μm or more and 40 μm or less, and most preferably 5 μm or more and 20 μm or less. It is preferable to form the filter medium 59 so that the absolute filtration accuracy is in the range of 3 μm or more and 20 μm or less.

  In addition, the filter medium of the second filtration device 57 is integrally formed as a three-layer structure, but instead of this, a filter medium in which each layer is formed in a single cylindrical shape is used, and concentric circles are formed so that these cylindrical filter media are stacked. You may comprise the 2nd filtration apparatus 57 by arrange | positioning in a shape. In this case, washing and roasting at the time of reuse may be performed by each filter medium alone, or may be performed in a state where the respective filter media are combined. Moreover, when forming in a cylindrical shape, a pleat may be put and the contact area of a liquid may be increased.

The second dope 36 is used to filter the raw material dope 36 through the filter medium 59 from the liquid flow path (hereinafter referred to as the outer liquid flow path) 58a outside the filter medium 59 and then the inner liquid flow path (hereinafter referred to as the inner liquid flow path). It discharges from the 2nd filtration apparatus 57 through 58b (it calls a liquid flow path). The raw material dope 36 is filtered in the order of the first layer 59a, the second layer 59b, and the third layer (the most downstream layer) 59c of the filter medium 59. For this reason, the damage generated from the sintered metal fibers of the first layer 59a and the second layer 59b is filtered by the third layer 59c, which is the most downstream layer, and therefore may be discharged to the inner liquid flow path 58b. Disappear. In addition, it is preferable that the liquid feeding pressure from the outer side liquid flow path 58a to the inner side liquid flow path 58b is the range of 1 * 10 < ⁵ > Pa or more and 1 * 10 < ⁶ > Pa or less. In order to make the liquid feeding pressure less than 1 × 10 ⁵ Pa, it is necessary to increase the absolute filtration accuracy of the filter medium, and it may be difficult to obtain a dope suitable for film formation. Alternatively, the flow rate of the solution may be reduced, but in this case, the productivity of the dope is lowered, which is not preferable. Further, when the liquid feeding pressure is increased, it is necessary to improve the durability of the filtering device main body 58, which causes a high cost.

  When the filter medium 59 of the second filter device 57 is regenerated, the filter medium 59 is heated and roasted at a temperature at which the metal fibers of the filter medium 59 do not melt. Thereby, the filter cake adhering to the sintered metal fiber which is the filter medium 59 can be burned and removed. For example, when stainless steel is used for the sintered metal fiber, the roasting temperature is preferably 350 ° C. or more and 500 ° C. or less, more preferably 350 ° C. or more and 450 ° C. or less, and most preferably 350 ° C. or more. It is 420 degrees C or less. The roasting time is preferably 2 hours or more and 8 hours or less, more preferably 2 hours or more and 6 hours or less, and most preferably 2 hours or more and 5 hours or less. By roasting under the above conditions, the trapped material of the filter medium can be removed, and the generation of damaged materials can be suppressed. When the time is less than 2 hours, the removal of the filter cake is insufficient. When the time is 8 hours or longer, the removal of the filter cake is sufficient, but the cost is reduced and the efficiency is reduced, and unnecessary roasting is performed. There is a possibility that the number of damaged items increases, and both are not preferable. In addition, by setting the heating rate in the roasting to 5 ° C./min or more and 100 ° C./min or less, the metal fiber is not suddenly heated, and an increase in breakage is suppressed.

  The additive solution 60 and the matting agent dispersion 61 are added in-line to the raw material dope 36 filtered by the second filtration device 57. An additive solution (for example, an ultraviolet absorber solution) 60 and a matting agent dispersion 61 are prepared in advance and placed in stock tanks 62 and 63. The additive solution 60 and the matting agent dispersion 61 are fed from the stock tanks 62 and 63 by the pumps 64 and 65, respectively. The additive solution 60 and the matting agent dispersion 61 are mixed by a static mixer 66 to be uniform, and then added in-line to the raw material dope 36. The static mixer 66 is not particularly limited. For example, when a static mixer manufactured by Noritake Co. having a tube diameter of 15 mm or more and 25 mm or less is used, one having 30 to 80 elements may be used. preferable. Alternatively, other types of in-line mixers such as a sulzer mixer manufactured by Sulzer and a HiMixer manufactured by Toray can be preferably used.

  The additive solution 60 and the matting agent dispersion 61 are added in-line to the raw material dope 36 by the static mixer 67 and then mixed to obtain a uniform casting dope. The static mixer 67 is not particularly limited. For example, in a static mixer manufactured by Noritake Co., the number of elements may be 24 or more and 60 or less when the tube diameter is 80 mm or more and 200 mm or less. preferable. The casting dope is cast from the casting die 70 onto the support. Alternatively, other types of in-line mixers such as a sulzer mixer manufactured by Sulzer and a HiMixer manufactured by Toray can be preferably used.

  In the present invention, it is preferable to mix the additive solution, particularly the ultraviolet absorber solution 60 and the matting agent dispersion 61, with the raw material dope 36 just before casting. That is, it is necessary to perform a defoaming step before casting the raw material dope 36 for defoaming. However, if an ultraviolet absorber is added to the raw material dope 36, the ultraviolet absorber may be decomposed in the raw material dope. As the matting agent, silicon dioxide or the like that is not normally dissolved in an organic solvent is used. For this reason, if the matting agent is previously contained in the raw material dope 36, there is a possibility that the raw material dope 36 is deposited on the pipe or the like when the raw material dope 36 is transferred. Further, the matting agent is captured by the filter medium of the first filtration device 54 and the second filtration device 57, which is not preferable.

The material of the casting die 70 is preferably a precipitation hardening type stainless steel. It is preferable to use a material having a thermal expansion coefficient of 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less. Moreover, what has corrosion resistance substantially equivalent to SUS316 in the forced corrosion test in electrolyte aqueous solution can also be used. Further, a material having corrosion resistance 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 is used. Furthermore, it is preferable that the casting die 70 is manufactured by grinding a material that has passed one month or more after casting. This prevents the dope from flowing uniformly in the casting die 70 and prevents streaks and the like from occurring in the casting film described later. It is preferable to use a casting die 70 and a feed block which will be described later have a liquid contact surface finishing accuracy of 1 μm or less in terms of surface roughness and straightness of 1 μm / m or less in any direction. The slit clearance that can be adjusted in the range of 0.5 mm to 3.5 mm by automatic adjustment is used. About the corner | angular part of the liquid-contact part of the lip | tip end of the casting die 70, the thing of 50 micrometers or less over the slit full width is used. Moreover, it is preferable to use what was adjusted so that the shear rate in the casting die 70 might be set to 1 (1 / sec)-5000 (1 / sec).

  The width of the casting die 70 is not particularly limited, but it is preferable to use a casting die having a width of about 1.01 to 1.3 times the width of the final film. Further, during film formation, it is preferable to attach a temperature controller so as to be maintained at a predetermined temperature. The casting die 70 is preferably a coat hanger type. Furthermore, it is more preferable that thickness adjusting bolts (heat bolts) are provided at predetermined intervals in the width direction of the casting die 70 and an automatic thickness adjusting mechanism using heat bolts is attached. In particular, it is preferable to set a heat bolt profile according to the amount of pump 56 (preferably a high-precision gear pump) according to a preset program. Further, a thickness meter (for example, an infrared thickness meter) (not shown) may be provided in the film production line 50, and feedback control may be performed by an adjustment program based on a profile by the thickness meter. The thickness difference between any two points in the width direction of the product film, excluding the casting edge portion, is adjusted within 1 μm, and the difference between the minimum value and the maximum value in the width direction thickness is adjusted to 3 μm or less. Preferably, adjusting to 2 μm or less is more preferable. Moreover, it is preferable to use the one whose thickness accuracy is adjusted to ± 1.5 μm or less.

More preferably, a cured film is formed at the tip of the lip. A method for forming the cured film is not particularly limited, and examples thereof include ceramic coating, hard chrome plating, and a nitriding method. 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 70, and have no adhesion to the dope are preferable. Specific examples include tungsten carbide (WC), Al ₂ O ₃ , TiN, Cr ₂ O _{3 and the} like, but it is particularly preferable to use WC. The WC coating can be performed by a thermal spraying method.

  In order to prevent the dope flowing out to the slit end of the casting die 70 from locally drying and solidifying, it is preferable to attach a solvent supply device (not shown) to the slit end. A solvent that solubilizes the dope (for example, a mixed solvent of 86.5 parts by mass of dichloromethane, 13 parts by mass of acetone, and 0.5 parts by mass of n-butanol) is formed by both ends of the casting bead, ends of the die slit, and outside air. It is preferable to supply near the periphery of the three-phase contact line. It is preferable to supply each side of the end portion in a range of 0.1 mL / min to 1.0 mL / min because it is possible to prevent foreign matters from being mixed in the cast film. In addition, it is preferable to use a pump having a pulsation rate of 5% or less for supplying the liquid.

  A casting band 73 is provided below the casting die 70 so as to span the rotating rollers 71 and 72. The casting band 73 travels endlessly as the rotating rollers 71 and 72 are rotated by a driving device (not shown). The moving speed of the casting band 73, that is, the casting speed is preferably a constant speed within a range of 10 m / min to 200 m / min. Further, in order to set the surface temperature of the casting band 73 to a predetermined value, it is preferable that a heat transfer medium circulation device 74 is attached to the rotary rollers 71 and 72. The surface temperature of the casting band 73 is preferably −20 ° C. to 40 ° C. A heat transfer medium flow path is formed in the rotation rollers 71 and 72, and the temperature of the rotation rollers 71 and 72 is set to a predetermined value by passing through the heat transfer medium maintained at a predetermined temperature. Can hold.

  The width of the casting band 73 is not particularly limited, but it is preferable to use one having a range of 1.05 to 1.5 times the casting width of the dope. It is preferable to use a surface polished to have a surface roughness of 0.05 μm or less. The material is preferably made of stainless steel, and more preferably made of SUS316 so as to have sufficient corrosion resistance and strength. Moreover, it is preferable to use the thickness unevenness of the entire casting band 73 of 0.5% or less.

It is preferable to adjust the tension generated in the casting band 73 when the rotating rollers 71 and 72 are driven to be 10 ⁴ N / m to 10 ⁵ N / m. Further, the relative speed difference between the casting band 73 and the rotary rollers 71 and 72 is adjusted to be 0.01 m / min or less. It is preferable that the speed fluctuation of the casting band 73 is 0.5% or less, and the meandering in the width direction that occurs when the casting band 73 rotates once is 1.5 mm or less. In order to control this meandering, it is more preferable to provide a detector (not shown) for detecting both ends of the casting band 73 and perform feedback control based on the measured value. Furthermore, it is preferable to adjust so that the vertical position fluctuation accompanying the rotation of the rotary roller 71 on the surface of the casting band 73 immediately below the casting die 70 is 200 μm or less.

A rotating drum (not shown) can be used as a support instead of the rotating rollers 71 and 72 and the casting band 82. In this case, it is preferable that the rotation can be performed with high accuracy so that the rotation speed unevenness is 0.2% or less. The rotating drum preferably has an average surface roughness of 0.01 μm or less, and preferably has a surface subjected to a hard chrome plating treatment or the like. Thereby, sufficient hardness and durability can be improved. In addition, it is preferable that the surface defects of the rotating drum, the casting band 82, and the rotating rollers 71 and 72 are minimized. Specifically, there is no pinhole of 30 μm or more, and the number of pinholes of 10 μm or more and less than 30 μm is 1 / m ² or less, and the number of pinholes of less than 10 μm is preferably ² / m ² or less.

  The casting die 70, the casting band 73, and the like are accommodated in the casting chamber 75. A temperature control facility 76 is attached to keep the temperature in the casting chamber 75 at a predetermined value. It is preferable that the temperature of the casting chamber 75 is −10 ° C. to 57 ° C. Further, a condenser (condenser) 77 for condensing and recovering the volatile organic solvent is provided. The condensed and liquefied organic solvent is recovered and regenerated by the recovery device 78 and then reused as a dope preparation solvent.

  A dope is cast from the casting die 70, and a casting film 79 is formed on the casting band 73 while forming a casting bead. In addition, it is preferable that the temperature of dope at this time exists in the range of -10 degreeC-57 degreeC. In order to stabilize the formation of the casting bead, the decompression chamber 80 is preferably attached to the rear surface of the casting bead and adjusted to a desired pressure. The back surface of the bead is preferably depressurized in a range of −2000 Pa to −10 Pa than the pressure with the front surface. Furthermore, it is preferable to attach a jacket (not shown) in order to keep the temperature of the decompression chamber 80 at a predetermined temperature. The temperature of the decompression chamber 80 is not particularly limited, but is preferably equal to or higher than the condensation point of the organic solvent used. In order to keep the shape of the casting bead desired, it is preferable to attach a suction device (not shown) to the edge portion of the casting die 70. The edge suction air volume is preferably in the range of 1 L / min to 100 L / min.

  The casting film 79 moves as the casting band 73 travels. At this time, air ducts 81, 82, and 83 are preferably provided to evaporate the solvent in the cast film 79. The attachment positions of the air ducts 81 to 83 are provided in the upper upstream portion, the upper downstream portion, and the entire lower portion of the casting band 73. In addition, the attachment position and form of the air ducts 81 to 83, the number of attachments, and the like are not limited to those in the illustrated example, and may be changed as appropriate. Further, it is preferable that a wind shielding plate 84 is provided in order to suppress the surface variation of the film surface caused by blowing dry air onto the casting film 79 immediately after casting. In addition, although the example which uses the casting band as a support body is shown in FIG. 2, it is also possible to use a casting drum. The surface temperature of the casting drum is preferably -20 ° C to 40 ° C.

  After the casting film 79 has self-supporting properties, it is peeled off from the casting band 73 as a wet film 86 while being supported by a peeling roller 85. The amount of residual solvent at the time of stripping is preferably 20% by mass to 250% by mass based on the solid content. Thereafter, the transfer section 90 provided with a large number of rollers is conveyed, and then fed into the tenter dryer 92. In the transfer part 90, the drying of the wet film 86 is advanced by sending the drying air of desired temperature from the ventilation duct 91. FIG. At this time, the temperature of the drying air is preferably 20 ° C to 250 ° C. In the crossing section 90, it is also possible to apply a draw to the wet film 86 by making the rotational speed of the downstream roller faster than the rotational speed of the upstream roller.

  The wet film 86 sent to the tenter-type dryer 92 is dried while its both edges are gripped by a clip and conveyed. Moreover, it is preferable to divide the inside of the tenter dryer 92 into different temperature zones to adjust the drying conditions. It is also possible to stretch the wet film 86 in the width direction using the tenter dryer 92. Thus, it is preferable to stretch at least one direction of the wet film 86 in the casting direction and the width direction by 0.5% to 300% by the crossing portion 90 and / or the tenter dryer 92.

  The wet film 86 dried to a predetermined residual solvent amount by the tenter dryer 92 is sent as a film 93 to the ear clip device 87. In the edge-cutting device 87, both side edges of the film 93 are cut at a constant width. The cut film is sent to the crusher 95 by a cutter blower (not shown). The edge of the film is crushed by the crusher 95 into 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 either from the said casting process to the process of winding up the said film.

  Next, the film 93 is sent to a drying chamber 97 provided with a large number of rollers 96. Although the temperature in the drying chamber 97 is not specifically limited, It is preferable that it is the range of 50 to 160 degreeC. In the drying chamber 97, the film 93 is conveyed while being wound around the roller 96, and the solvent is volatilized and dried. Further, an adsorption recovery device 98 is attached to the drying chamber 97. The volatile solvent is adsorbed and recovered by the adsorption recovery device 98. The atmosphere from which the solvent component has been removed is blown again into the drying chamber 97 as dry air. The drying chamber 97 is more preferably divided into a plurality of sections in order to change the drying temperature. In addition, a preliminary drying chamber (not shown) is provided between the ear opener 94 and the drying chamber 97, and the preliminary drying of the film 93 can suppress the change in the shape of the film due to the rapid increase in the film temperature. preferable.

  The film 93 is conveyed to the cooling chamber 99 and cooled to approximately room temperature. A humidity control chamber (not shown) may be provided between the drying chamber 97 and the cooling chamber 99. Air adjusted to the desired humidity and temperature of the film 93 is blown in the humidity control chamber. Thereby, generation | occurrence | production of the curling of the film 93 and the winding defect at the time of winding can be suppressed.

  The forced charge removal device (charge removal bar) 100 is provided so that the charged voltage while the film 93 is conveyed is in a predetermined range (for example, −3 kV to +3 kV). In FIG. 2, an example provided on the downstream side of the cooling chamber 99 is illustrated, but the position is not limited thereto. Furthermore, it is preferable to provide a knurling roller 101 and to impart knurling to both edges of the film 93 by embossing. In addition, it is preferable that the unevenness | corrugation of the knurled location is 1 micrometer-200 micrometers.

  Immediately before being conveyed to the winding chamber 103, a defect of the film 93 is detected. The online defect detection apparatus 102 is not particularly limited. For example, a CCD method, a laser scattered light method, or other known methods can be used, and it is most preferable to use a laser scattered light method. In the laser scattered light method, laser light is irradiated from one side of the traveling film 93 to scan the entire width of the film. Moreover, the presence of a foreign substance can be detected by receiving the laser beam on the other side of the film 93 and detecting the scattering of the laser beam. The detection limit is not particularly limited, but is preferably 30 μm or more, more preferably 20 μm or more, and most preferably 10 μm or more. As the detection limit is decreased, deterioration of the optical properties of the film due to foreign substances can be suppressed. However, it has been found that even if foreign matter of less than 10 μm is present in the film 93, it is preferably used as the base film of the optical functional film intended in the present invention.

  Finally, the film 93 is taken up by the take-up roller 104 in the take-up chamber 103. At this time, it is preferable to wind the sheet while applying a desired tension with the press roller 105. More preferably, the tension is gradually changed from the start to the end of winding. The film 93 to be wound is preferably at least 100 m in the longitudinal direction (casting direction). Further, the width direction is preferably 600 mm or more, and more preferably 1400 mm or more and 1800 mm or less. Also, it is effective when it is larger than 1800 mm. The thickness of the film is preferably 15 μm or more and 100 μm or less.

  In the solution casting method of the present invention, when casting the dope, two or more kinds of dopes can be simultaneously laminated or sequentially laminated. Furthermore, you may combine both casting. 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. The film composed of multiple layers by co-casting preferably has a layer thickness on the air side and / or a layer on the support side of 0.5% to 30% of the total film thickness. Furthermore, when performing simultaneous lamination co-casting, it is preferable to enclose the high-viscosity dope with the low-viscosity dope when casting the dope from the die slit to the support. Moreover, when performing simultaneous lamination co-casting, it is preferable that the dope inside is encapsulated with a dope having a higher alcohol composition ratio than the dope when the dope is cast from the die slit to the support.

  From casting die, decompression chamber, support structure, co-casting, peeling method, stretching, drying conditions for each process, handling method, curl, winding method after flatness correction, solvent recovery method, film recovery method The details are described in paragraphs [0617] to [0889] of JP-A-2005-104148. These descriptions can also be applied to the present invention.

[Performance / Measurement method]
(Curl degree / thickness)
The performance of the wound cellulose acylate film and the measurement method thereof are described in paragraphs [0112] to [0139] of JP-A-2005-104148. These are also applicable to the present invention.

[surface treatment]
It is preferable that at least one surface of the cellulose acylate 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]
(Antistatic, hardened layer, antireflection, easy adhesion, antiglare)
At least one surface of the cellulose acylate film may be undercoated.
Furthermore, it is preferable to use the cellulose acylate film as a base film as a functional material provided with another functional layer. 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. Further, the functional layers preferably contain at least one sort of antistatic agents ^1mg / ^{m 2 ~1000mg} / m 2 containing. In addition to the above, the method for applying a surface treatment functional layer for realizing various functions and properties on the cellulose acylate film is described in paragraphs [0890] to [1087] of JP-A-2005-104148. Detailed conditions and methods are also described. These are also applicable to the present invention.

(Use)
The cellulose acylate film is particularly useful as a polarizing plate protective film. A liquid crystal display device is produced using usually two polarizing plates in which a cellulose acylate film is bonded to a polarizer. However, the arrangement position of the liquid crystal layer and the polarizing plate is not particularly limited, and may be any known position. Japanese Patent Application Laid-Open No. 2005-104148 describes TN type, STN type, VA type, OCB type, reflection type, and other examples in detail as a liquid crystal display device. This method can also be applied to the present invention. The application also describes a cellulose acylate film provided with an optically anisotropic layer and a cellulose acylate film provided with antireflection and antiglare functions. Furthermore, the use as an optical compensation film is also described as a biaxial cellulose acylate film imparting 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 [1088] to [1265] of JP-A-2005-104148.

  Moreover, the cellulose triacetate film (TAC film) excellent in an optical characteristic can be obtained with the manufacturing method of this invention. This TAC film can be used as a polarizing plate protective film or a base film of a photographic photosensitive material. Furthermore, it can also be used as an optical compensation film for improving the viewing angle dependency of a liquid crystal display device for television applications. 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.

Examples are given below, but the present invention is not limited thereto. The used mass part is shown below.
[composition]
Cellulose triacetate (substitution degree 2.84, acetylation degree 61.0%, viscosity average degree of polymerization 306, water content 0.2% by weight, viscosity of 6% by weight in dichloromethane solution 420 mPa · s, average particle size 1.5 mm (Powder with a standard deviation of 0.5 mm) 89.3% by weight
Triphenyl phosphate 7.1% by weight
Biphenyl diphenyl phosphate 3.6% by weight
For 100 parts by weight of solid content consisting of
92% by weight of dichloromethane
8% by weight of methanol
A mixed solvent consisting of: The solid content concentration of the raw material dope 36 was 18.5% by weight.

The ultraviolet absorber (UV agent) solution 60 was prepared according to the following formulation.
UV agent a: 2 (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole 5.83% by weight
UV agent b: 2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -benzotriazole 11.66% by weight
Cellulose triacetate (same as for raw material dope preparation) 1.48% by weight
Triphenyl phosphate 0.12% by weight
Biphenyl diphenyl phosphate 0.06% by weight
Dichloromethane 74.38 wt%
Methanol 6.47% by weight
The ultraviolet absorbent solution 60 obtained by the above formulation was prepared, filtered twice with an Astropore 10 μm filter manufactured by Fuji Photo Film Co., Ltd., and placed in the stock tank 62.

The matting agent dispersion 61 was prepared according to the following formulation.
Silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) 2.00% by weight
Cellulose triacetate (same as for raw material dope preparation) 2.00% by weight
Triphenyl phosphate 0.16% by weight
Biphenyl diphenyl phosphate 0.08% by weight
Dichloromethane 88.10 wt%
7.66% by weight of methanol
A matting agent dispersion was prepared and dispersed with an attritor so that the volume average particle size was 0.5 μm. Here, the value measured with a particle size distribution measuring apparatus LA920 manufactured by Horiba, Ltd. was used as the volume average particle diameter. The dispersed liquid was filtered twice with an Astropore 10 μm filter manufactured by Fuji Photo Film Co., Ltd. and then placed in the stock tank 63.

  The cellulose triacetate used here has a residual acetic acid content of 0.1% by mass or less, a Ca content of 58 ppm, a Mg content of 42 ppm, a Fe content of 0.5 ppm, free acetic acid of 40 ppm, It contained 15 ppm of sulfate ion. The degree of substitution of the acetyl group with respect to the hydrogen at the 6-position hydroxyl group was 0.91. Further, 32.5% of all acetyl groups were acetyl groups in which the hydrogen of the hydroxyl group at the 6-position was substituted. Moreover, the acetone extraction part which extracted this TAC with acetone was 8 mass%, and the weight average molecular weight / number average molecular weight ratio was 2.5. The obtained TAC has a yellow index of 1.7, a haze of 0.08, a transparency of 93.5%, a Tg (glass transition temperature; measured by DSC) of 160 ° C., and a crystallization calorific value of It was 6.4 J / g. This TAC is synthesized using cellulose collected from cotton as a raw material.

  The film was manufactured using the film manufacturing line 50 shown in FIG. The raw material dope 36 in the mixing tank 30 was sent to the stock tank 52 by a high precision gear pump 51. The gear pump 51 has a function of increasing the pressure on the primary side, and liquid is fed by performing feedback control on the upstream side of the gear pump 51 by an inverter motor so that the pressure on the primary side becomes 0.8 MPa. A gear pump 51 having a volume efficiency of 99.2% and a discharge rate variation of 0.5% or less was used. The discharge pressure was 1.5 MPa.

  The raw material dope 36 was fed to the stock tank 52 by a pump 53 (volumetric efficiency 96%, discharge rate variation rate 2% or less, discharge pressure 0.5 MPa to 1.2 MPa) 53 to the first filtration device 54. Filter paper (# 63 manufactured by Toyo Filter Paper Co., Ltd.) was used as the filter medium of the first filtration device 54. The raw material dope 36 filtered by the first filtration device 54 was stored at 36 ° C. in the stock tank 55.

  Thereafter, the raw material dope 36 was fed to the second filtration device 57 by a pump (volumetric efficiency 96%, discharge rate variation rate 2% or less, discharge pressure 0.5 MPa to 1.5 MPa) 56. As the filter medium 59 of the second filtering device 57, a pleated cylindrical material made of sintered metal fibers was used. The material of the metal fiber is SUS316L, the average fiber diameter of the first layer 59a is 8 μm, the average fiber diameter of the second layer 59b is 4 μm, and the average fiber diameter of the third layer (the most downstream layer) 59c. Used was 20 μm. In addition, the filter medium 59 of the second filtration device 57 once used for film formation reached a predetermined pressure (1.0 MPa), and a so-called clogged one was regenerated by performing the following processing. In this regeneration method, the solvent was washed in the direction opposite to the filtration direction and then dried. Next, the filter medium 59 was placed in a heating furnace whose temperature was adjusted to 400 ° C. and roasted for 2 hours to be regenerated.

  The ultraviolet absorbent solution 60 and the matting agent dispersion 61 were fed to the static mixer 66 by pumps 64 and 65, respectively. A static mixer 66 having a tube diameter of 25.4 mm and 76 elements was used. The ultraviolet absorber solution 60 and the matting agent dispersion 61 were mixed and then supplied to the raw material dope 36. These were mixed by a static mixer 67 to obtain a dope for casting. The addition amount of the ultraviolet absorber was adjusted to 1.04% by weight with respect to the solid content concentration (polymer and plasticizer) of the raw material dope 36. The addition amount of the matting agent was 0.13% by weight with respect to the solid content concentration of the raw material dope 36.

  The casting die 70 was cast by adjusting the flow rate of the dope for casting at the discharge port of the casting die 70 so that the film thickness of the dried film was 80 μm. The casting width of the casting dope from the discharge port of the casting die 70 was 1700 mm. In order to adjust the temperature of the dope for casting to 36 ° C., a jacket (not shown) is provided in the casting die 70 and the inlet temperature of the heat transfer medium supplied into the jacket is set to 36 ° C. The casting die 70 and the piping were all kept at 36 ° C. during film formation. The casting die 70 is a coat hanger type die.

  Further, a decompression chamber 80 for decompressing this portion was installed on the primary side of the casting die 70. The degree of decompression of the decompression chamber 80 is adjusted so that a pressure difference of 1 Pa to 5000 Pa is generated before and after the casting bead, and this adjustment is made according to the casting speed. At that time, the pressure difference on both sides of the casting bead was set so that the length of the bead was 20 mm to 50 mm. The decompression chamber 80 was provided with a mechanism that can be set to a temperature higher than the condensation temperature of the gas around the casting portion. Labyrinth packings (not shown) were provided on the front and back surfaces of the beads at the die discharge port. Also, openings were provided at both ends of the die discharge port of the casting die. Further, an edge suction device (not shown) for adjusting the disturbance of both edges of the casting bead was attached to the casting die 70.

The material of the casting die 70 was a precipitation hardening type stainless steel, and was a material having a thermal expansion coefficient of 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less. In a forced corrosion test with an aqueous electrolyte solution, the material had a corrosion resistance substantially equivalent to that of SUS316. Further, even when immersed in a mixed solution of dichloromethane, methanol and water for 3 months, it had corrosion resistance that did not cause pitting (opening) at the gas-liquid interface. The finishing accuracy of the wetted surface of the casting die 70 was 1 μm or less in terms of surface roughness, the straightness was 1 μm / m or less in any direction, and the slit clearance was adjusted to 1.5 mm. As for the corner part of the liquid contact part at the tip of the lip of the casting die 70, the one processed so that R is 50 μm or less over the entire width of the slit was used. The shear rate inside the die was in the range of 1 (1 / sec) to 5000 (1 / sec). Further, a WC (tungsten carbide) coating was performed on the lip end of the casting die 70 by a thermal spraying method to provide a cured film.

  Further, a mixed solvent (dichloromethane: methanol = 50 weight) for solubilizing the casting dope is provided at the discharge port of the casting die 70 in order to prevent the casting dope flowing out from being locally dried and solidified. Part: 50 parts by weight) was supplied at 0.5 ml / min to the interface between the both ends of the casting bead and the discharge port. The pulsation rate of the pump supplying the mixed solvent was 5% or less. Further, the pressure on the back side of the casting bead was lowered by 150 Pa from the front side by the decompression chamber 80. A jacket (not shown) was attached to keep the internal temperature of the decompression chamber 80 constant at a predetermined temperature. A heat transfer medium adjusted to 35 ° C. was supplied into the jacket. The edge suction device can adjust the edge suction air volume so as to be in the range of 1 L / min to 100 L / min, and in the present embodiment, this is in the range of 30 L / min to 40 L / min. Adjusted appropriately.

A stainless steel endless band having a width of 2.1 m and a length of 70 m was used as the casting band 73 as a support. The casting band 73 was polished so that the thickness was 1.5 mm and the surface roughness was 0.05 μm or less. The material is made of SUS316 and has sufficient corrosion resistance and strength. The thickness unevenness of the entire casting band 73 was 0.5% or less. The casting band 73 was driven by two rotating rollers 71 and 72. At that time, the tension in the conveying direction of the casting band 73 was adjusted to 1 × 10 ⁵ N / m. Further, the relative speed difference between the casting band 73 and the rotating rollers 71 and 72 was adjusted to be 0.01 m / min or less. At this time, the speed fluctuation of the casting band 73 was set to 0.2% or less. Further, both end positions of the casting band 73 were detected and controlled so that the meandering in the width direction of one rotation was limited to 1.5 mm or less. The casting band 73 was installed in a casting chamber 75 having wind pressure fluctuation suppressing means (not shown). A casting dope was cast from the casting die 70 on the casting band 73.

As the rotating rollers 71 and 72, those capable of feeding a heat transfer medium therein were used so that the temperature of the casting band 73 could be adjusted. A 5 ° C. heat transfer medium was passed through the rotating roller 71 on the casting die 70 side, and a 40 ° C. heat transfer medium was passed through the other rotating roller 72 for drying. The surface temperature of the central part of the casting band 73 immediately before casting was 15 ° C., and the temperature difference between both side ends was 6 ° C. or less. The casting band 73 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 ² pinholes of less than 10 μm / It was used at m ² or less.

The temperature of the casting chamber 75 was kept at 35 ° C. using the temperature control equipment 76. The casting film 79 formed from the casting dope cast on the casting band 73 was first fed with drying air flowing parallel to the casting film 79 to dry the casting film 79. The overall heat transfer coefficient from the dry air to the cast film 79 was 24 kcal / (m ² · hr · ° C.). The temperature of the drying air was 135 ° C. for the air duct 81 arranged on the upstream side of the upper part of the casting band 73, and 140 ° C. for the air duct 82 arranged on the upper downstream side of the casting band 73. Moreover, the thing of the ventilation duct 83 arrange | positioned under the casting band 73 was 65 degreeC. The saturation temperature of each drying wind was around -8 ° C. The oxygen concentration in the dry atmosphere on the casting band 73 was kept at 5 vol%. In order to maintain this oxygen concentration at 5 vol%, the air was replaced with nitrogen gas. Further, in order to condense and recover the solvent in the casting chamber 75, a condenser 77 was provided, and its outlet temperature was set to -10 ° C.

  For 5 seconds after casting, a wind shielding plate 84 is installed so that the dry air does not directly hit the dope for casting and the casting film 79, and the static pressure fluctuation in the immediate vicinity of the casting die 70 is suppressed to ± 1 Pa or less. . When the solvent ratio in the casting film 79 reached 50% by mass on the dry basis, the film was removed from the casting band 73 as a film (wet film) 86 while being supported by the peeling roller 85. The solvent content on the basis of the dry weight is a value calculated by {(xy) / y} × 100, where x is the film weight at the time of sampling and y is the weight after drying the sampling film. It is. In order to suppress the peeling failure, the peeling speed (peeling roller draw) with respect to the speed of the casting band 73 was appropriately adjusted in the range of 100.1% to 110%. The surface temperature of the wet film 86 peeled off was 15 ° C. The drying rate on the casting band 73 was an average of 60% by mass dry weight reference solvent / min. The solvent gas generated by drying was condensed and liquefied by a condenser 77 at −10 ° C. and recovered by a recovery device 78. The recovered solvent was adjusted so that the water content was 0.5% or less. The drying air from which the solvent was removed was heated again and reused as drying air. The wet film 86 was conveyed through the roller of the cross section 90 and sent to the tenter dryer 92. In the crossing portion 90, 40 ° C. dry air was blown from the air duct 91 to the wet film 86. In addition, a tension of about 50 N / m was applied to the wet film 86 during the conveyance by the roller of the crossing section 90.

  The wet film 86 sent to the tenter dryer 92 was conveyed through the drying zone while being fixed at both ends with clips, and was dried by drying air during this time. The clip was cooled by supplying a heat transfer medium at 20 ° C. The clip was conveyed by a chain, and the speed fluctuation of the sprocket was 0.5% or less. Further, the interior of the tenter dryer 92 was divided into three zones, and the drying air temperature in each zone was set to 90 ° C., 110 ° C., and 120 ° C. from the upstream side. The gas composition of the drying air was set to a saturated gas concentration at −10 ° C. The average drying rate in the tenter dryer 92 was 120% by mass (dry weight reference solvent) / min. The conditions of the drying zone were adjusted so that the amount of residual solvent in the film 93 was 7% by mass at the outlet of the tenter dryer 92. Stretching was also performed in the width direction while being conveyed in the tenter dryer 92. When the width of the wet film 86 before stretching was 100%, the film was stretched so that the width after stretching was 103%. The stretch rate (tenter driven draw) from the peeling roller 85 to the entrance of the tenter dryer 92 was 102%. The stretching ratio in the tenter dryer 92 is 10% or less, and the difference between the substantial stretching ratios at any two points at a position 10 mm or more away from the biting start position by the clip is 20%. The difference in the stretching ratio of points was 5% or less. Further, the ratio of the length from the clip clamping start position to the clamping release position with respect to the length from the inlet to the outlet of the tenter dryer 92 was 90%. The solvent evaporated in the tenter dryer 92 was condensed and liquefied at a temperature of −10 ° C. and recovered. A condenser (condenser) was provided for condensation recovery, and the outlet temperature was set to -8 ° C. The condensed solvent was reused after adjusting the water content to 0.5% by mass or less. And it sent out as the film 93 from the tenter type dryer 92.

Then, the ear-cleaving device 94 cuts off both ends of the film 93 within 30 seconds from the exit of the tenter dryer 92. Ears 50 mm on both sides were cut with an NT-type cutter, and the cut ears were blown to a crusher 95 with a cutter blower (not shown) and crushed into chips of about 80 mm ² on average. This chip was used again as a raw material for dope production together with TAC flakes as a raw material for dope preparation. The oxygen concentration in the drying atmosphere of the tenter dryer 92 was maintained at 5 vol%. Note that the air was replaced with nitrogen gas in order to maintain the oxygen concentration at 5 vol%. Before drying at a high temperature in a drying chamber 97 described later, the film 93 was preheated in a predrying chamber (not shown) to which 100 ° C. drying air was supplied.

  The film 93 was dried at a high temperature in the drying chamber 97. The drying chamber 97 was divided into four sections, and drying air at 120 ° C., 130 ° C., 130 ° C., and 130 ° C. was sent from the upstream side to the drying chamber from a blower duct (not shown). The conveying tension of the film 93 by the roller 96 was set to 50 N / m to 150 N / m, and the film was dried for about 10 minutes until the residual solvent amount finally became 0.3% by mass. The wrap angle (film wrapping center angle) of the roller 96 was 90 degrees and 180 degrees (exaggerated in FIG. 2). The roller 96 is made of aluminum or carbon steel, and hard chrome plating is applied to the surface. The roller 96 has a flat surface shape and a blasted matte surface. All film position fluctuations due to the rotation of the roller 96 were 50 μm or less. The roller deflection at a tension of 100 N / m was selected to be 0.2 mm or less.

  The solvent gas contained in the dry air was adsorbed and recovered using an adsorption recovery device 98. The adsorbent used here was activated carbon, and desorption was performed using dry nitrogen. The recovered solvent was reused as a dope preparation solvent with the water content adjusted to 0.3 mass% or less. The drying air contains plasticizers, UV absorbers and other high-boiling substances in addition to the solvent gas, so these were removed by a cooler and pre-adsorber to be removed by cooling and used for recycling. And adsorption / desorption conditions were set so that VOC (volatile organic compound) in the outdoor exhaust gas was finally 10 ppm or less. Moreover, the solvent amount collect | recovered by a condensation method among all the evaporation solvents was 90 mass%, and most of the remainder was collect | recovered by adsorption | suction.

  The dried film 93 was conveyed to the 1st humidity control chamber (not shown). A drying air of 110 ° C. was supplied to the transition portion between the drying chamber 97 and the first humidity control chamber. Air having a temperature of 50 ° C. and a dew point of 20 ° C. was supplied to the first humidity control chamber. Further, the film 93 was conveyed to a second humidity control chamber (not shown) that suppresses the curling of the film 93. In the second humidity control chamber, air having a temperature of 90 ° C. and a humidity of 70% was directly applied to the film 93.

  The film 93 after humidity control was cooled to 30 ° C. or lower in the cooling chamber 99 and then subjected to ear cutting at both ends again with an ear cutting device (not shown). The forced charge removal device (charge removal bar) 100 was installed so that the charged voltage of the film 93 during conveyance was always in the range of −3 kV to +3 kV. Further, knurling was applied to both ends of the film 93 by a knurling roller 101. The knurling is imparted by embossing from one side of the film 93, the width for imparting the knurling is 10 mm, and the pressure applied by the knurling roller so that the height of the unevenness is 12 μm higher than the average thickness of the film 93 on average. It was set.

  The number of foreign matters in the film 93 was counted using the online defect detection device 102. The online defect detection device 102 irradiates laser light from one side of the traveling film 93, receives the light on the opposite surface of the film while scanning the entire width of the film 93, and detects scattering of the laser light by the foreign matter. A foreign object is detected. In the present embodiment, adjustment was performed so that foreign matters of 30 μm or more can be detected. In this state, the number of foreign matters in the product 500 m was 24. When this foreign material was collected and confirmed using a microscope, no metallic fibrous foreign material was found.

  Then, the film 93 was conveyed to the winding chamber 103. The winding chamber 103 was maintained at a room temperature of 28 ° C. and a humidity of 70% RH. Inside the winding chamber 103, an ion wind static elimination device (not shown) was also installed so that the charged voltage of the film 93 was −1.5 kV to +1.5 kV. The product width of the film 93 (thickness 80 μm) thus obtained was 1330 mm. The diameter of the winding roller 104 was 169 mm. The tension pattern was such that the winding start tension was 400 N / m and the winding end was 150 N / m. The total winding length was 3940 m. The variation range of winding deviation at the time of winding (sometimes referred to as oscillating width) was ± 5 mm, and the winding deviation period with respect to the winding roller 104 was 400 m. The pressing pressure of the press roller 105 against the winding roller 104 was set to 40 N / m. The temperature of the film during winding was 25 ° C., the water content was 1.4% by mass, and the residual solvent amount was 0.3% by mass. The average drying rate was 20% by mass (dry weight reference solvent) / min throughout the entire process. Moreover, there was no winding looseness and wrinkles, and no winding slip occurred in the impact test at 10G. The roll appearance was also good. In addition, the number of foreign objects detected by the online defect detection apparatus 102 was 24, but there were 0 damaged items derived from metal fibers.

  The film roll of the film 93 was stored in a storage rack at 25 ° C. and 55% RH for 1 month and further examined in the same manner as described above. As a result, no significant change was observed. Further, no adhesion was observed in the roll. In addition, after the film 93 was formed, no peeling residue of the casting film 79 formed from the dope was observed on the casting band 73.

  A comparative experiment was performed using a filter medium 59 in which the average diameter of the metal fibers of the first layer 59a was 8 μm, the average diameter of the metal fibers of the second layer 59b was 4 μm, and the average diameter of the metal fibers of the third layer 59c was 8 μm. Other conditions are the same as in the example. In the detection of foreign matters using the online defect detection device 102, the total number of foreign matters per 500 m of the product film was 80 pieces, of which 60 pieces were damaged due to metal fibers.

  From this example, it was found that even when the filtration accuracy of the sintered metal fiber filter medium was increased, it was possible to produce a solution containing no foreign matter due to the metal fiber breakage.

It is the schematic of the equipment which manufactures the dope raw material dope concerning this invention. It is the schematic of the installation which manufactures dope which concerns on this invention, and forms a film. It is sectional drawing of the filtration apparatus for manufacturing dope which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Raw material dope production line 36 Raw material dope 50 Film production line 56 1st filtration apparatus 76 2nd filtration apparatus 58 Filtration apparatus main body 58a Outer liquid flow path 58b Inner liquid flow path 59 Filter medium 93 Film

Claims (13)

In a filtration device that includes a filter medium that is roasted and reused, and that filters a dope containing cellulose acylate and a chlorinated solvent,
A first filter made of sintered metal fibers having an average diameter of 4 μm or more and 8 μm or less, and a sintered filter made of sintered metal fibers having an average diameter of 15 μm or more and 60 μm or less. A filter device comprising the filter medium having a filter inside a filter device body.   2. The dope filtering device according to claim 1, wherein the filter medium includes a third filter made of sintered metal fibers having an average diameter of 8 μm or more and 30 μm or less, which is disposed so as to overlap the upstream side of the first filter. .   3. The dope filtering device according to claim 2, wherein the second filter has an average diameter of sintered metal fibers larger than that of the third filter.   The filtration device according to any one of claims 1 to 3, wherein the filter medium is pleated. In a dope filtration method of filtering a dope containing cellulose acylate and a chlorinated solvent by a filtration device equipped with a filter medium that is roasted and reused,
A first filter made of sintered metal fibers having an average diameter of 4 μm or more and 8 μm or less, and a sintered filter made of sintered metal fibers having an average diameter of 15 μm or more and 60 μm or less. A dope filtration method, wherein the dope is sent to the filter device body of the filter device including the filter medium having a filter inside the filter device body and filtered.   6. The dope filtering method according to claim 5, wherein the filter medium has a third filter made of sintered metal fibers having an average diameter of 8 μm or more and 30 μm or less, which is disposed so as to overlap the upstream side of the first filter. .   The dope filtration method according to claim 6, wherein the second filter has an average diameter of sintered metal fibers larger than that of the third filter.   The dope filtering method according to any one of claims 5 to 7, wherein the filter medium is pleated.   The dope filtering method according to any one of claims 5 to 8, wherein the filtering device main body includes the filtering medium in which the second filter is disposed inside the cylindrical first filter.   The dope filtration method according to any one of claims 5 to 9, wherein the second filter is a filter disposed on the most downstream side of the filter medium.   The dope filtration method according to any one of claims 5 to 10, wherein the filter medium is roasted at a temperature of 350 ° C to 500 ° C and reused.   12. The sintered metal fiber is formed of a material containing at least one of austenitic stainless steel, martensitic stainless steel, ferritic stainless steel, or a composite stainless steel thereof. The dope filtration method according to any one of the preceding claims. In the solution casting method in which the dope is filtered by a filtration device equipped with a filter medium that is roasted and reused , and then cast,
A first filter made of sintered metal fibers having an average diameter of 4 μm or more and 8 μm or less, and a sintered filter made of sintered metal fibers having an average diameter of 15 μm or more and 60 μm or less. Sending a dope containing cellulose acylate and a chlorinated solvent to the filtration device body of the filtration device provided with the filter medium having a filter inside the filtration device body, and filtering,
A solution casting method characterized in that the dope having undergone the filtration is cast on a support, peeled off, and dried to produce a film.

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