JP2007069420A - Method of manufacturing film, and the film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a film which is superior in transparency, heat resistance, and flatness and reduced in defect, and efficient in productivity, and provide the film manufactured by the method. <P>SOLUTION: In the method of manufacturing the film, dope prepared by dissolving a polymer in an organic solvent is poured on a support and dried to produce the film with a glass transition temperature of at least 250°C and a total light transmittance of at least 70%. The adjusted dope is evacuated/deaerated before being poured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a film production method capable of producing a film excellent in heat resistance, transparency, flatness and dimensional stability with high productivity, and a film produced by the production method.

  A film made of an organic polymer is generally made into a molten state by applying a temperature equal to or higher than its thermal deformation temperature or melting point, and is discharged from the die as a molten film to form a film. In contrast, a polymer having a heat distortion temperature or melting point close to the decomposition temperature or a heat deformation temperature or melting point higher than the decomposition temperature is decomposed simultaneously with melting. The resulting solution is cast on a support and then formed into a film by a solution casting method in which the solvent is removed. Examples of such a polymer include cellulose triacetate, aromatic polyamide, and aromatic polyimide. Films obtained by the solution casting method may be disadvantageous in terms of productivity, such as it takes time to remove the solvent, compared to films obtained by melt casting, but film properties such as surface smoothness may be excellent. In many cases, a film obtained by a solution casting method is preferably used depending on the intended use. However, on the other hand, solution casting methods are required to improve productivity while maintaining excellent film characteristics.

  In recent years, in the field of flat panel displays such as liquid crystal display elements and organic electroluminescence elements (hereinafter referred to as “organic EL elements”), the substrate is replaced from glass to plastic in order to improve breakage resistance, reduce weight, and reduce thickness. It is being considered. In particular, there is a strong demand for plastic substrates in the field of mobile information communication device display devices such as mobile phones, electronic notebooks, laptop computers, and other portable information terminals.

  In order to impart conductivity to the plastic substrate, a semiconductor film such as an oxide of indium oxide, tin oxide, or tin-indium alloy, a metal film such as an oxide film of gold, silver, or palladium alloy, or the semiconductor film Studies have been made to form a transparent conductive layer combined with the metal film on a plastic substrate. In addition, various functionalizations such as liquid crystal alignment layers and TFTs have been studied. In any case, high heat resistance and transparency are required for plastic substrates. Moreover, in order to maintain the characteristics of various functional layers, a film used as a substrate is required to be free from defects such as bubbles and dust and to be excellent in smoothness.

  Patent Documents 1 and 2 describe a transparent conductive film using a polyimide having an alicyclic structure and a thin film transistor substrate. The polyimide is excellent in transparency and exhibits high heat resistance with a glass transition temperature of 250 ° C. or higher. Moreover, it is excellent in the solubility with respect to the organic solvent with respect to a general wholly aromatic polyimide, and is suitable for solution film forming.

  Patent Document 3 discloses 6,6′-dihydroxy-4,4,4 ′, 4 ′, 7,7′-hexamethyl-2,2′-spirobichroman (hereinafter also referred to as “spirobichromandiol”). And polyester films derived from isophthalic acid and terephthalic acid. The polyester provides a film having excellent mechanical properties with excellent transparency and flexibility, and exhibits high heat resistance with a glass transition temperature of 250 ° C. or higher. Moreover, it is excellent in solubility in low boiling point solvents such as dichloromethane, and is suitable for solution film formation.

Patent Document 4 describes a polyester film derived from 9,9-bis (4-hydroxyphenyl) fluorene (hereinafter also referred to as “bisphenolfluorene”), isophthalic acid and terephthalic acid. Patent Document 5 describes a polyester film derived from alkyl-substituted bisphenolfluorene, isophthalic acid and terephthalic acid. Furthermore, Patent Document 6 describes a polyester film derived from bisphenolfluorene in which the ortho position of phenol is substituted with halogen or the like.
Polyesters derived from these substituted or unsubstituted bisphenolfluorenes and isophthalic acid and terephthalic acid all have a glass transition temperature (Tg) of about 300 ° C. or higher, and have excellent transparency and elongation at break. Film can be produced. Moreover, it is excellent in solubility in low boiling point solvents such as dichloromethane, and is suitable for solution film formation.

  Many studies have been made on the use of a film using a polymer having excellent transparency and heat resistance as a plastic substrate as described above. However, on the other hand, a polymer having excellent transparency and heat resistance can be formed by solution casting, but there are few film defects and a method for producing a film having excellent flatness by solution casting with high productivity. unknown.

Many documents such as Patent Document 7 describe a solution film-forming method of cellulose triacetate. Cellulose triacetate can be formed at high speed using a low-boiling solvent such as dichloromethane, and it is known that it is excellent in productivity even in the case of solution film formation.
However, as a result of applying the same method as cellulose triacetate to a film having excellent transparency and heat resistance as described above, the present inventors can produce a film having few film defects and excellent flatness with high productivity. It became clear that it was difficult.
JP 2003-141936 A (Claims) JP 2003-168800 A (Claims) Japanese Patent Laid-Open No. 11-302364 (Claims) JP-A-3-28222 (Claims) International Publication No. WO99 / 18141 (claim) JP 2002-145998 A (Claims) JP 2002-103360 A (Claims)

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to provide a film that is excellent in transparency and heat resistance, has few film defects, and has excellent flatness with high productivity. It is in providing the film manufactured by the manufacturing method and the manufacturing method of this film.

As a result of intensive studies to achieve the above object, the present inventor has developed a production method capable of producing a film having excellent transparency, heat resistance, few film defects, and excellent flatness by solution casting. The headline and the present invention were completed.
That is, the said subject of this invention is achieved by the following means.

(1) A film manufacturing method in which a dope in which a polymer is dissolved in an organic solvent is cast on a support and dried to form a film having a glass transition temperature of 250 ° C. or higher and a total light transmittance of 70% or higher. There,
A method for producing a film, wherein the prepared dope is degassed under reduced pressure before casting.

  (2) The method for producing a film according to (1), wherein the dope before casting is subjected to ultrasonic treatment.

  (3) The method for producing a film according to (1) or (2), wherein the dope before casting is filtered using a filter aid.

  (4) The method for producing a film according to any one of (1) to (3), wherein the dried film is subjected to two-stage heat treatment.

〔一般式（１）中、環αは単環式または多環式の環を表し、２つの環はスピロ結合によって結合される。〕

〔一般式（２）中、環βおよび環γは単環式または多環式の環を表し、２つの環γはそれぞれ同一若しくは異なっていてもよい。また、環βおよび環γは、環β上の１つの４級炭素原子によって連結される。〕 (5) The polymer has a repeating unit containing a spiro structure represented by the following general formula (1) or a cardo structure represented by the following general formula (2): (1) to (4) The manufacturing method of the film in any one.

[In general formula (1), ring α represents a monocyclic or polycyclic ring, and the two rings are connected by a spiro bond. ]

[In general formula (2), ring β and ring γ represent a monocyclic or polycyclic ring, and the two rings γ may be the same or different. Ring β and ring γ are connected by one quaternary carbon atom on ring β. ]

(6) A film produced by the method for producing a film according to any one of (1) to (5).
(7) The film according to (6), wherein the number of bubbles per 1 m ² is 10 or less.

(8) The film according to (6) or (7), wherein the number of foreign matters of 5 μm or more per 70 mm ² is 60 or less.

  (9) The film according to any one of (6) to (8), wherein a dimensional change rate when held at 200 ° C. for 5 hours is ± 0.1% or less.

The present invention provides a film in which a dope having a polymer dissolved in an organic solvent is cast on a support and dried to form a film having a glass transition temperature of 250 ° C. or higher and a total light transmittance of 70% or higher. According to the present invention, a film having excellent transparency and heat resistance, few film defects, and excellent flatness can be produced with high productivity by degassing the dope before casting under reduced pressure. It becomes.
Furthermore, according to the present invention, it is possible to provide a film having excellent transparency and heat resistance, few film defects, and excellent flatness.

Hereafter, the manufacturing method of the film of this invention is demonstrated in detail.
In the present specification, “to” is used as a meaning including numerical values described before and after the lower limit value and the upper limit value.

[Method for producing film]
In the method for producing a film of the present invention, a dope in which a polymer is dissolved in an organic solvent is cast on a support and dried to form a film having a glass transition temperature of 250 ° C. or higher and a total light transmittance of 70% or higher. The film manufacturing method is characterized in that the dope before casting is degassed under reduced pressure. In the present invention, a solution in which a polymer is dissolved in an organic solvent is referred to as “dope”.
According to the method for producing a film of the present invention, the dope before casting is degassed under reduced pressure so that the film of the present invention is excellent in transparency and heat resistance, has few film defects, and has excellent flatness. Can be manufactured.
The film of the present invention is a film produced by the method for producing a film of the present invention, and the number of bubbles per 1 m ² is preferably 10 or less.

The film production method of the present invention comprises a step of dissolving a polymer in an organic solvent to prepare a dope (dope preparation step), a step of degassing the dope under reduced pressure (vacuum degassing step), and vacuum degassing. And a step of casting the dried dope on a support and drying it (casting drying step), and other various steps as required.
Below, the manufacturing method of the film of this invention is demonstrated for every process.

(Dope preparation process)
The dope preparation step in the present invention is a step of preparing a dope by dissolving a polymer in an organic solvent.

-Polymer-
The polymer that can be used in the present invention (hereinafter also referred to as “polymer in the present invention”) may be a thermoplastic resin or a curable resin, and is not particularly limited, but is soluble in at least one organic solvent and is a film. In this case, a polymer having a glass transition temperature of 250 ° C. or higher and a total light transmittance of 70% or higher is used.
Examples of the polymer in the present invention are preferably those having a glass transition temperature of 250 ° C. or higher and substantially colorless and transparent, for example, fluorine-containing polyimide, polyimide containing an alicyclic structure, or rigid Examples include polyarylate containing a linking group and polyamide. Particularly preferable examples of the polymer in the present invention include polymers having a repeating unit including a spiro structure represented by the following general formula (1) or a cardo structure represented by the following general formula (2).

〔一般式（１）中、環αは単環式または多環式の環を表し、２つの環はスピロ結合によって結合される。〕

[In general formula (1), ring α represents a monocyclic or polycyclic ring, and the two rings are connected by a spiro bond. ]

〔一般式（２）中、環βおよび環γは単環式または多環式の環を表し、２つの環γはそれぞれ同一若しくは異なっていてもよい。また、環βおよび環γは、環β上の１つの４級炭素原子によって連結される。〕

[In general formula (2), ring β and ring γ represent a monocyclic or polycyclic ring, and the two rings γ may be the same or different. Ring β and ring γ are connected by one quaternary carbon atom on ring β. ]

The ring α in the general formula (1) represents a monocyclic or polycyclic ring, and examples thereof include indane, chromane, and benzofuran. Further, the two rings α are connected by a spiro bond. Preferable examples of the polymer having a repeating unit containing a spiro structure represented by the general formula (1) include a polymer having a repeating unit containing a spirobichroman structure represented by the following general formula (3). .
The ring β in the general formula (2) represents a monocyclic or polycyclic ring, and examples thereof include fluorene and 1,4-bibenzocyclohexane. Ring β contains a quaternary carbon atom, and ring β and ring γ are connected by such a quaternary carbon atom. Ring γ represents a monocyclic or polycyclic ring, and examples thereof include benzene and naphthalene. The two rings γ may be the same or different from each other. Preferable examples of the polymer having a repeating unit containing a cardo structure represented by the general formula (2) include a polymer having a repeating unit containing a fluorene structure represented by the following general formula (4).

In the general formula (3), R ⁴¹ each independently represents a hydrogen atom or a substituent, and R ⁴² represents a substituent. R ⁴¹ and R ⁴² may be connected to each other to form a ring. m and n represent an integer of 0 to 3. Preferred examples of the substituent are a halogen atom, an alkyl group, and an aryl group. More preferred examples of R ⁴¹ are a hydrogen atom, a methyl group, and a phenyl group, and more preferred examples of R ⁴² are a chlorine atom, a bromine atom, a methyl group, an isopropyl group, a t-butyl group, and a phenyl group. .

In general formula (4), R ⁶¹ and R ⁶² each independently represent a substituent. R ⁶¹ and R ⁶² may be connected to each other to form a ring. j and k represent the integer of 0-4. Preferred examples of the substituent are a halogen atom, an alkyl group, and an aryl group. More preferred examples of R ⁶¹ and R ⁶² are chlorine atom, bromine atom, methyl group, isopropyl group, t-butyl group, and phenyl group.

  The polymer containing the structure represented by the general formulas (1) to (4) in the repeating unit may be a polymer linked by various bonding methods such as polycarbonate, polyester, polyamide, polyimide, polyurethane, Polyesters derived from bisphenol compounds having the structures represented by the general formulas (1) to (4) are preferable from the viewpoints of heat resistance, transparency, and solubility in organic solvents.

  As preferred examples of polyesters derived from bisphenol compounds having the structures represented by the general formulas (1) to (4) (hereinafter also referred to as “polyesters in the present invention”), the following general formulas (5) to (6) The polyester which has a repeating unit represented by this can be mentioned.

  In general formula (5), ring β represents a ring which may have a monocyclic or polycyclic substituent. Ring β has the same meaning as ring β in formula (2) above. Preferred ring β is a polycyclic ring containing at least one aromatic ring. Preferred substituents on the ring β are an alkyl group, an aryl group, and a halogen atom, and more preferred examples include a chlorine atom, a bromine atom, a methyl group, an isopropyl group, a tert-butyl group, and a phenyl group. L represents a divalent linking group composed of a hydrocarbon which may have a substituent. Preferred L is alkylene or arylene, and preferred alkylene is alkylene containing an alicyclic structure. Among these, arylene connection is particularly preferable, and examples thereof include phenylene, naphthalene, and biphenylene. Moreover, the preferable substituent of an arylene connection is an alkyl group, an aryl group, and a halogen atom, More preferably, they are a methyl group, a chlorine atom, and a bromine atom.

Moreover, since the polyester which has a repeating unit represented by the said General formula (5) improves the solubility with respect to a solvent by making it the copolymer of 2 or more types of repeating units from which L differs, 2 different L It is particularly preferable to use it as a copolymer of seeds or more. As a preferred combination of repeating units of the copolymer, a combination of two or more selected from the combination of paraphenylene and metaphenylene, paraphenylene, 2,6-naphthalene and 4,4′-biphenylene is selected. Can be mentioned. R ¹ and R ² each represent a substituent, and preferred substituents are an alkyl group, an aryl group, and a halogen atom, and more preferably a chlorine atom, a bromine atom, a methyl group, an isopropyl group, a tert-butyl group, and a phenyl group. Is mentioned. l and m represent an integer of 0-4.

  In general formula (6), ring α represents a ring which may have a monocyclic or polycyclic substituent, and the two rings are connected by a spiro bond. Ring α has the same meaning as ring α in formula (1) described above. L represents a divalent linking group composed of a hydrocarbon which may have a substituent. Preferred L is alkylene or arylene, and preferred alkylene is alkylene containing an alicyclic structure. Among these, arylene connection is particularly preferable, and examples thereof include phenylene, naphthalene, and biphenylene. Also, preferred substituents for arylene linkage are an alkyl group, an aryl group, and a halogen atom, and more preferably a methyl group, a chlorine atom, and a bromine atom.

Moreover, since the polyester which has a repeating unit represented by General formula (6) improves the solubility with respect to a solvent by making it the copolymer of 2 or more types of repeating units from which L differs, 2 types from which L differs It is particularly preferable to use as the above copolymer. Preferred combinations of preferred repeating units of the copolymer include a combination of paraphenylene and metaphenylene, or a combination of two or more selected from three types of paraphenylene, 2,6-naphthalene and 4,4′-biphenylene. Can be mentioned. R ¹ and R ² each represent a substituent, and preferred substituents are an alkyl group, an aryl group, and a halogen atom, and more preferably a chlorine atom, a bromine atom, a methyl group, an isopropyl group, a tert-butyl group, and a phenyl group. Is mentioned. l and m represent an integer of 0 to 3;

  Moreover, a preferable example of the repeating unit represented by the general formula (5) includes a repeating unit represented by the following general formula (7).

In the general formula (7), R ³ and R ⁴ each represent a substituent, and preferred substituents are an alkyl group, an aryl group, and a halogen atom, and more preferably a chlorine atom, a bromine atom, a methyl group, an isopropyl group, Examples thereof include a tert-butyl group and a phenyl group. j and k represent the integer of 0-4. L represents a divalent linking group composed of a hydrocarbon which may have a substituent. Preferred L is alkylene or arylene, and preferred alkylene is alkylene containing an alicyclic structure. Among these, arylene connection is particularly preferable, and examples thereof include phenylene, naphthalene, and biphenylene. Also, preferred substituents for arylene linkage are an alkyl group, an aryl group, and a halogen atom, and more preferably a methyl group, a chlorine atom, and a bromine atom.

Moreover, since the polyester which has a repeating unit represented by General formula (7) improves the solubility with respect to a solvent by making it the copolymer of 2 or more types of repeating units from which L differs, 2 types from which L differs It is particularly preferable to use as the above copolymer. As a preferable combination of preferable repeating units of the copolymer, a combination of two or more selected from the combination of paraphenylene and metaphenylene, paraphenylene, 2,6-naphthalene, and 4,4′-biphenylene is selected. Can be mentioned. R ¹ and R ² each represent a substituent, and preferred substituents are an alkyl group, an aryl group, and a halogen atom, and more preferably a chlorine atom, a bromine atom, a methyl group, an isopropyl group, a tert-butyl group, and a phenyl group. Is mentioned. l and m represent an integer of 0-4.

  Although the preferable specific example (exemplary compound PC-1 to PS-8) of the polyester in this invention is given to the following, this invention is not limited to this. In addition, the number of a repeating unit represents a copolymerization ratio (mol%), and a homopolymer is described as 100.

  The molecular weight of the polymer in the present invention is preferably 10,000 or more in terms of weight average molecular weight. More preferably, the weight average molecular weight is 20,000 to 300,000, and particularly preferably 30,000 to 150,000. When the molecular weight is 10,000 or more, the mechanical properties of the obtained molded product are advantageous when applied to a molded product such as a film. On the other hand, when the molecular weight is 300,000 or less, it is advantageous in terms of controlling the molecular weight in synthesis, and the viscosity of the solution is not too high, which is advantageous in handling. The viscosity corresponding to the molecular weight can be used as a guide.

  As described above, the polymer in the present invention may be a copolymer having a plurality of types of repeating units including the structures represented by the general formulas (1) to (7). Moreover, you may copolymerize well-known repeating units other than the repeating unit containing the structure represented by the said General formula (1)-(7) in the range which does not impair the effect of this invention.

  The total molar percentage of the repeating units including the structures represented by the general formulas (1) to (7) in the polymer in the present invention is preferably 40 to 100 mol%, and preferably 60 to 100 mol%. Is more preferable, and it is further more preferable that it is 80-100 mol%. When the polymer in this invention has multiple types of repeating units containing the structure represented by General formula (1)-(7), the solubility with respect to a solvent and transparency may improve, and it is preferable. In this case, the proportion of any one of them is preferably 5 to 95 mol%, more preferably 20 to 80 mol%, and particularly preferably 30 to 70 mol%. When the ratio of the repeating unit including the structure represented by the general formulas (1) to (7) in the polymer in the present invention is the above, it is advantageous from the viewpoints of transparency, heat resistance, and solubility.

  The higher heat resistant temperature of the polymer in the present invention is preferably high, and the glass transition temperature by DSC measurement can be used as a guide. In this case, the glass transition temperature of the polymer in the present invention is 250 ° C. or higher, preferably 300 ° C. or higher, particularly preferably 350 ° C. or higher. Further, a case where a glass transition temperature is not substantially observed within a measurement range (for example, 420 ° C. or lower) is also preferable as the polymer in the present invention. It has a repeating unit containing the structure represented by General formula (4) or (7) among the polymers which have a repeating unit containing the structure represented by General formula (1)-(7) contained in the polymer in this invention. A polymer is more preferable because of its high heat resistance. Furthermore, the polyester having the repeating unit represented by the general formula (7) is most preferable because it easily develops a glass transition temperature of 300 ° C. or higher and is excellent in solubility in a low boiling point solvent.

-Organic solvent-
The present invention uses a dope obtained by dissolving the above-mentioned polymer in an organic solvent. The organic solvent that can be used in the present invention is not particularly limited as long as it can dissolve the polymer in the present invention, but the solubility of the polymer in the present invention at a liquid temperature of 20 ° C. under normal pressure is 5% by mass or more. More preferably, it is 10% by mass or more, and particularly preferably 15% by mass or more.
The preferred organic solvent type varies depending on the type of polymer in the present invention, and cannot be generally stated. For example, ethers such as tetrahydrofuran, anisole, and 1,4-dioxane; benzene, cyclohexane, isophorone, toluene, Hydrocarbons such as xylene; esters such as γ-butyrolactone, ethyl acetate, butyl acetate, methyl benzoate and dimethyl phthalate; alcohols such as benzyl alcohol, phenethyl alcohol, methanol, ethanol and n-butanol; cyclohexanone , Cyclopentanone, acetone, methyl ethyl ketone, ketones such as acetophenone; N, N-dimethylacetamide (also referred to as DMAc), N-methyl-2-pyrrolidone (also referred to as NMP), N, N-dimethylformamide (Also referred to as DMF), nitrobenzene, nitrogen-containing solvents such as benzonitrile; dichloromethane, chloroform, 1,2-dichloroethane, and a halogen-containing solvents such as such as chlorobenzene. However, the present invention is not limited to these.
As other examples of the organic solvent, those described in “Solvent Handbook” edited by Kodansha Scientific may be used. The organic solvent may be used as a mixture of two or more, such as a mixture of a good solvent and a poor solvent, or a mixture of a high boiling point solvent and a low boiling point solvent.

  The organic solvent mentioned above can select a thing with high solubility with respect to the kind of polymer in this invention used. Examples of the case of using the above-described polyester according to the present invention, which is mentioned as a particularly preferable example of the polymer according to the present invention, include, for example, tetrahydrofuran, anisole, 1,4-dioxane, toluene, xylene, γ-butyrolactone, methyl benzoate, Dimethyl phthalate, benzyl alcohol, phenethyl alcohol, cyclohexanone, cyclopentanone, acetophenone, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N, N-dimethylformamide, nitrobenzene, benzonitrile, dichloromethane, chloroform 1,2-dichloroethane, chlorobenzene and the like are mentioned as highly soluble solvents.

  Of these, organic solvents having a lower boiling point are preferred as the organic solvent used in the present invention. The boiling point of the organic solvent is preferably 170 ° C. or lower, more preferably 120 ° C. or lower. Examples of the organic solvent having high solubility and low boiling point for the polyester in the present invention include, for example, tetrahydrofuran, anisole, 1,4-dioxane, toluene, xylene, cyclohexanone, cyclopentanone, N, N-dimethylacetamide. N, N-dimethylformamide, dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and the like. Of these, low-boiling halogen-containing solvents such as dichloromethane, chloroform, and 1,2-dichloroethane are solvents having high solubility in polyester and low boiling point in the present invention.

-Additives-
Various additives (for example, a plasticizer, an ultraviolet inhibitor, a deterioration inhibitor, fine particles, an optical property modifier, etc.) according to the use can be added to the dope in the present invention in each preparation step. The additive may be added at any time in the dope preparation step, but the additive may be added to the final preparation step of the dope preparation step.

  As the plasticizer preferably added to the dope in the present invention, phosphate ester, carboxylate ester, or glycolate ester is used. Examples of phosphate esters include triphenyl phosphate (TPP) and tricresyl phosphate (TCP), cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate.

  Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of the phthalic acid ester include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethyl hexyl phthalate (DEHP). Examples of the citrate ester include triethyl O-acetylcitrate (OACTE) and tributyl O-acetylcitrate (OACTB), acetyltriethyl citrate, and acetyltributyl citrate.

Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters.
Examples of glycolic acid esters include triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, and butyl phthalyl butyl glycolate. Further trimethylolpropane tribenzoate, pentaerythritol tetrabenzoate, ditrimethylolpropane tetraacetate, ditrimethylolpropane tetrapropionate, pentaerythritol tetraacetate, sorbitol hexaacetate, sorbitol hexapropionate, sorbitol triacetate tripropionate, inositol pentaacetate Sorbitan tetrabutyrate is also preferably used.

  Among them, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diethyl hexyl phthalate, triacetin, ethyl phthalyl ethyl glycolate, trimethylol propane tribenzoate, penta Erythritol tetrabenzoate, ditrimethylolpropane tetraacetate, pentaerythritol tetraacetate, sorbitol hexaacetate, sorbitol hexapropionate, sorbitol triacetate tripropionate, etc. are preferred, especially triphenyl phosphate, diethyl phthalate, ethyl phthalyl ethyl glycolate, tri Methylolpropane tribe Zoeto, pentaerythritol tetrabenzoate, ditrimethylolpropane tetra acetate, sorbitol hexaacetate, sorbitol hexapropionate, sorbitol triacetate tripropionate are preferred. These plasticizers may be used alone or in combination of two or more. The amount of the plasticizer added is not unambiguous depending on the type of the polymer in the present invention, but is preferably within a range that does not greatly impair the film properties of the present invention. % By mass is a preferred range.

  These plasticizers include (di) pentaerythritol esters described in JP-A No. 11-124445, glycerol esters described in JP-A No. 11-246704, diglycerol esters described in JP-A No. 2000-63560, The citrate esters described in JP-A No. 11-92574 and the substituted phenyl phosphate esters described in JP-A No. 11-90946 are described in known literatures.

  Deterioration inhibitors (eg, antioxidants, peroxide decomposers, radical inhibitors, metal deactivators, acid scavengers, amines) and UV inhibitors may be added to the dope in the present invention. About these deterioration preventing agents and ultraviolet ray preventing agents, JP-A-60-235852, JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107854, JP-A-6-118233, JP-A-6-148430, JP-A-7-11056, JP-A-7-11055, JP-A-7-11056, JP-A-8-29619, No. 8-239509 and JP-A 2000-204173. The amount of these added is preferably 0.01 to 3% by mass, more preferably 0.01 to 1% by mass, based on the total amount of the polymer in the present invention. When the addition amount is in the above range, the deterioration preventive agent or the ultraviolet preventive bleed-out (bleeding out) to the film surface is rarely observed, and it can work effectively. As a particularly preferred example of the deterioration preventing agent, butylated hydroxytoluene (BHT) can be mentioned.

  Particularly preferably, the dope in the present invention contains one or more ultraviolet absorbers. The ultraviolet absorbent is preferably excellent in the ability to absorb ultraviolet rays having a wavelength of 380 nm or less and having little absorption of visible light having a wavelength of 400 nm or more. Examples include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. Particularly preferred ultraviolet absorbers are benzotriazole compounds and benzophenone compounds. Among these, a benzotriazole-based compound is preferable because unnecessary coloring is small.

  Preferred examples of the ultraviolet ray inhibitor include 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], Triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4 -Hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2,2-thio -Diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- ( , 5-Di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1,3,5-trimethyl- 2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, etc. It is done.

  Among these, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol- Bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] is most preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di-tert A phosphorus processing stabilizer such as -butylphenyl) phosphite may be used in combination. The amount of these compounds added is preferably 1 ppm to 3.0%, more preferably 10 ppm to 2% in terms of mass ratio with respect to the total amount of the polymer in the present invention.

  In order to adjust the retardation of the film of the present invention, an aromatic compound having at least two aromatic rings may be used. The aromatic compound can be used in the range of 0.01 to 20 parts by mass, preferably in the range of 0.05 to 15 parts by mass, with respect to 100 parts by mass of the polymer in the present invention. More preferably, it is used in the range of 1 to 10 parts by mass. Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring.

  The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring). The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As a hetero atom of the unsaturated heterocyclic ring, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.

  In addition, inorganic fine particles such as silica, kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide, and alumina can be added to the dope in the present invention.

-Preparation of dope-
Next, the dissolution process (dope preparation process) will be described. The dope in the present invention is prepared by dissolving the polymer and other additives in the present invention in a desired organic solvent as necessary. The dissolution method is not particularly limited, and may be room temperature, and further, a cooling dissolution method, a high temperature dissolution method, a supercritical dissolution method, or a combination thereof is performed. In the case of dissolution at room temperature, the polymer in the present invention can be mixed with a solvent or an additive at a temperature of 0 to 55 ° C., and can be dissolved by stirring and mixing in a dissolution vessel or the like. Regarding dissolution, when the polymer in the present invention is a powder, it is important to immerse it sufficiently in a solvent, and it is preferable not to generate so-called mamako (the polymer powder part in the present invention in which the solvent does not spread at all). . For this reason, it may be preferable to add a solvent in advance to the stirring vessel, and then add the polymer in the present invention under reduced pressure in the dissolution vessel. On the other hand, it may be preferable to add the polymer in the present invention in advance to the stirring vessel, and then add the solvent under reduced pressure in the dissolution vessel. It is also a preferable dope preparation method that the polymer in the present invention is preliminarily moistened with a poor solvent such as alcohol, and then an organic solvent which becomes a good solvent for the polymer in the present invention is added.

  When using a plurality of organic solvents, the order of addition is not particularly limited. For example, after adding the polymer according to the present invention to the main solvent that is a good solvent for the polymer according to the present invention, another organic solvent (for example, a poor solvent such as alcohol) may be added. The main solvent may be added after the polymer in the present invention is previously wetted. This method is effective in preventing non-uniform dissolution. In stirring, the polymer in the present invention and the organic solvent may be mixed, and then left as it is, and the polymer in the present invention may be sufficiently swollen with the organic solvent, followed by stirring to obtain a uniform dope. It is preferable to adjust the addition amount of the polymer in this invention so that it may contain 5-40 mass% in the dope in this invention, and it is more preferable that it is 10-30 mass%.

  Next, the cooling dissolution method will be described. That is, the preparation of the polymer solution (dope) in the present invention may be performed according to a cooling dissolution method. First, the polymer in the present invention is gradually added to an organic solvent with stirring at a temperature around room temperature (-10 to 40 ° C). When using a plurality of solvents, the order of addition is not particularly limited. For example, after adding the polymer in the present invention to the main solvent, another organic solvent (for example, a solvent such as alcohol) may be added, or conversely, after the poor solvent has been previously wetted with the polymer in the present invention. A main solvent may be added. This method is effective in preventing non-uniform dissolution (so-called mamako prevention). The amount of the polymer in the present invention is preferably adjusted so that it is contained in the mixture with the organic solvent in an amount of 5 to 40% by mass, and more preferably 10 to 30% by mass. Furthermore, you may add arbitrary additives in a mixture.

  Next, the mixture is cooled to -100 to -10 ° C (preferably -80 to -10 ° C, more preferably -50 to -20 ° C). The cooling can be performed, for example, in a dry ice / methanol bath (−75 ° C.) or a cooled diethylene glycol solution (−30 to −20 ° C.). When cooled in this way, the mixture of the polymer and the organic solvent in the present invention may solidify. Although the cooling rate is not particularly limited, in the case of batch-type cooling, the viscosity of the polymer solution in the present invention increases with cooling, and the cooling efficiency is poor. It is preferable to do. If the dissolution is insufficient, the cooling and heating operations may be repeated. Whether the dissolution is sufficient or not can be judged by visually observing the appearance of the solution. In the cooling and melting method, it is desirable to use a sealed container in order to avoid moisture mixing due to condensation during cooling. In the cooling and heating operation, when the pressure is applied during cooling and the pressure is reduced during heating, the dissolution time can be shortened. In order to perform pressurization and decompression, it is desirable to use a pressure-resistant container.

  In the present invention, a high temperature dissolution method is also preferably used. That is, the preparation of the polymer solution (dope) in the present invention may be performed according to a high temperature dissolution method. First, the polymer in the present invention is gradually added to an organic solvent with stirring at a temperature around room temperature (-10 to 40 ° C). When using a plurality of solvents, the order of addition is not particularly limited. For example, after the polymer in the present invention is added to the main solvent, another solvent (for example, a poor solvent such as an alcohol) may be added, or conversely after the poor solvent has been previously wetted with the polymer in the present invention. A main solvent may be added. This method is effective in preventing non-uniform dissolution. The polymer solution in the present invention is preferably swollen in advance by adding the polymer in the present invention to a mixed organic solvent containing various solvents. In that case, the polymer in the present invention may be gradually added to any solvent at −10 to 40 ° C. with stirring, and in some cases, it may be pre-swelled with a specific organic solvent and then another combination solvent may be added. In addition, the mixture may be mixed to obtain a uniform swelling solution, or may be swollen with two or more organic solvents, and then the remaining solvent may be added.

  Next, the organic solvent mixture is preferably heated to 70 to 240 ° C. under a pressure of 0.2 MPa to 30 MPa (preferably 80 to 220 ° C., more preferably 100 to 200 ° C., most preferably 100 to 190 ° C. ). The heating may be, for example, high-pressure steam or an electric heat source. A pressure vessel or a pressure line is required for high pressure, but any of iron, stainless steel, or other metal pressure vessel or line may be used, and is not particularly limited. Next, since these heated solutions cannot be applied as they are, it is necessary to cool them below the lowest boiling point of the solvent used. In that case, it is common to cool to -10-50 degreeC and to return to a normal pressure. For cooling, the high-pressure and high-temperature vessel or line containing the polymer solution in the present invention may be left at room temperature, and more preferably, the apparatus may be cooled using a coolant such as cooling water. Note that heating and cooling operations may be repeated in order to accelerate dissolution. Whether or not the dissolution is sufficient can be determined by merely observing the appearance of the solution with the naked eye. In the high-pressure and high-temperature dissolution method, a closed container is used to avoid evaporation of the solvent. In addition, the dissolution time can be further shortened by increasing the pressure or reducing the pressure in the swelling step. In order to perform pressurization and decompression, a pressure-resistant container or line is essential.

  The dope according to the present invention obtained by the above-described method is characterized in that a high concentration dope is obtained, and the dope according to the present invention having a high concentration and excellent stability can be obtained without relying on the means of concentration. However, in order to achieve further dissolution in a short time, a method of concentrating using a concentration means after dissolving at a low concentration is also employed. The concentration method is not particularly limited. For example, the low-concentration solution is guided between the cylindrical body and the rotation trajectory of the outer periphery of the rotating blade rotating in the circumferential direction, and the temperature between the solution and the solution. A method of obtaining a high-concentration solution while evaporating the solvent by giving a difference (for example, JP-A-4-259511), a heated low-concentration solution is blown into the container from the nozzle, and the solution is applied from the nozzle to the inner wall of the container The solvent is flash-evaporated, the solvent vapor is extracted from the container, and the high-concentration solution is extracted from the bottom of the container (for example, US Pat. Nos. 2,541,012, 2,858,229, and 4, No. 414,341, No. 4,504,355, etc.).

  In the present invention, the viscosity of the dope immediately before film formation may be in a range that allows casting, and is usually preferably adjusted in the range of 0.1 Pa · s to 2000 Pa · s, and particularly preferably 0.8. 5 Pa · s to 400 Pa · s is preferable. In addition, although the temperature at this time will not be specifically limited if it is the temperature at the time of the casting, Preferably it is -5-70 degreeC, More preferably, it is -5-55 degreeC.

Next, filtration of the dope in the present invention will be described. Prior to casting the polymer solution in the present invention, it is preferable to filter off foreign matters such as undissolved matter, dust and impurities using a suitable filter medium such as a wire mesh or flannel. For the filtration of the dope in the present invention, it is preferable to use a filter having an absolute filtration accuracy of 0.005 mm or more and 0.1 mm or less, and further using a filter having an absolute filtration accuracy of less than 0.005 mm and 0.0005 mm or more. Is more preferable. In that case, it is preferable to form a film by filtration at a filtration pressure of 16 kg / cm ² or less (preferably 12 kg / cm ² or less, more preferably 10 kg / cm ² or less, particularly preferably 2 kg / cm ² or less). The foreign matter in excess of 50μm by filtration can achieve substantially zero per area 70 mm ^2, further for 5~50μm foreign matter can be achieved following 60 per area 70 mm ^2. Here, the number of foreign matters in the film obtained in the present invention was observed with an optical microscope (100 times magnification with a transmission light source), the number of foreign matters at that time was measured over 10 locations, and this evaluation was repeated five times. This is defined as the number of foreign objects.

When the film of the present invention is used as a plastic substrate for displays or the like, various functional layers such as a conductive layer and a gas barrier layer are installed on the film. In this case, if there is a foreign substance in the film, it affects the surface smoothness and may deteriorate the characteristics of various functional layers. In such a case, the number of foreign matters contained in the film of the present invention is preferably substantially zero for foreign matters exceeding 50 μm per 70 mm ² area, and further, foreign matters of 5 to 50 μm are 30 per 70 mm ² area. Or less, more preferably 10 or less.

  As a method for achieving such a number of foreign matters, a method of reducing the average pore diameter of the filter used when filtering the dope in the present invention can be mentioned. The average pore diameter is preferably 1 μm to 40 μm, more preferably 2 μm to 20 μm, and particularly preferably 3 μm to 10 μm. On the other hand, the method of reducing the average pore diameter of the filter requires caution because the dope filtration pressure in the present invention may increase or the filtration rate may be reduced. In such a case, in the present invention, a method of filtering using a filter aid can be mentioned as a particularly preferable method.

  The filter aid here is an average particle size larger than the average pore size of the filter used, and is an irregularly shaped fine powder that does not dissolve in the dope of the present invention. Filtration efficiency can be improved by laminating (pre-coating). Although there is no restriction | limiting in particular as a kind of filter aid, A cellulose, diatomaceous earth, pearlite, activated carbon, powdered charcoal is used preferably, Among these, a cellulose, diatomaceous earth, and pearlite are preferable, the average length of 40-300 micrometers cellulose, an average Diatomaceous earth having a particle size of 2 to 50 μm and pearlite having an average particle size of 2 to 50 μm are particularly preferable. For example, as the cellulose, “Fibral Cell BH-100” (manufactured by Celite, USA), “Diacel-150” (manufactured by Cellulose-Fullstoff Fabric), “Solker-Flock BW-40” (manufactured by Brown), As for diatomaceous earth, “Radiolite” (manufactured by Showa Chemical Industry Co., Ltd.), “Celite SSC”, “C-512”, “C-505” (manufactured by Johns Manbile International Corporation), “Daikalite Super” "Aid", "Daikalite 2500", "Daikalite 6000" (manufactured by Grefco), as perlite "Topco perlite" (manufactured by Showa Chemical Industry Co., Ltd.), "Daikalite perlite" (manufactured by Daikalite Orient) Is mentioned. These filter aids can be used in combination as needed, and the filtration efficiency can be improved compared to using them alone by combining different materials, different shapes, and different average sizes. There is a case.

The amount of the filter aid used is not generally determined by the size of the filter aid and the required level of removing foreign matter, but is preferably 0.2 to 5 kg, more preferably 0.5 to 1 m ^{2 of} the filtration area. 4 kg. If the amount of the auxiliary agent used is too small, the filtration effect may be reduced, foreign matter removal may be insufficient, the filtration pressure may increase, or the filtration rate may decrease. Moreover, even if there is too much usage-amount of auxiliary agent, the filtration effect may not change and it is not economically advantageous.

  When filtering the dope in the present invention, an adsorbent may be used in combination as necessary. Examples of the adsorbent used include activated alumina, activated clay, activated carbon, magnesium oxide, aluminum oxide, and silicon oxide. These may be used alone or in combination with a filter aid. When the polymer in the present invention contains a highly polar substance (monomers such as bisphenol compounds and dicarboxylic acids, and ionic substances such as quaternary ammonium salts and Na salts), it is preferable to use an adsorbent. . In general, the amount of the adsorbent used is preferably 0.1% by mass to 3% by mass, and more preferably 0.2% by mass to 2% by mass with respect to the mass of the dope in the present invention.

  Regarding the filtration method using the filter aid in the present invention, a slurry made of the same solvent as the organic solvent used in the filter aid and the dope in the present invention is filtered in advance, and a precoat layer of the filter aid is formed on the filter surface. There are a pre-coating method in which the dope according to the present invention is filtered using this as a filter medium, and a body feed method in which an appropriate amount of filter aid is mixed in the dope according to the present invention for filtration. On the other hand, with respect to the adsorption operation, there is a method in which an adsorbent is added to a dope solution and adsorbed by stirring, that is, a contact adsorption method, or a method in which a dope is adsorbed through a layer filled with an adsorbent, that is, a stationary phase adsorption method . In the present invention, any filtration method and adsorption method can be applied and combined. In particular, the filtration using a filter aid is particularly preferably a method in which the precoat method and the body feed method are used in combination. Although the adsorption temperature and the filtration temperature vary depending on the type of foreign matter to be removed, generally 0 to 120 ° C is preferable, and 10 to 100 ° C is more preferable.

(Low pressure degassing process)
In the method for producing a film of the present invention, the dope is degassed under reduced pressure in a vacuum degassing step before casting the dope according to the present invention. Thereby, the air remaining in the dope is degassed, and a film with less generation of bubbles can be manufactured with high productivity. The number of bubbles contained in the film of the present invention is preferably evaluated by visual observation under crossed Nicols, and is preferably 10 or less per 1 m ² . More preferably, it is 5 or less, and particularly preferably 1 or less. In general, as a method for degassing air contained in an organic solvent, a method of applying vibration with ultrasonic waves, a method of bubbling a gas having low solubility in an organic solvent such as argon gas, or the like is used. On the other hand, the dope for forming a solution is a polymer solution having a high concentration and a high viscosity, and is difficult to deaerate. In addition, unlike general coatings, it is usually a thick film of about 100 μm, and it is known that bubbles are difficult to escape during film-forming and drying, and pinholes are likely to occur in the film.

  Regarding the deaeration of the dope for solution casting, Japanese Patent Application Laid-Open No. 2003-200445 describes a high-concentration cellulose acylate solution before casting on a casting support in order to prevent failure due to casting bubbles. A solution casting method characterized by degassing to 90% or less of the amount of saturated dissolved air under 1 atm is described. According to the examples of the publication, 1) a method of reducing the pressure at the time of dope preparation (subsequent filtration), 2) a method of heating and leaving the dope after filtration, 3) a method of reducing the pressure of the dope after filtration, and 4) filtration. Degassing is performed by any method such as a method of flushing the dope afterwards, 5) a method of lowering the dope temperature in the casting die or at the discharge port than that at the time of preparing the dope, and the film is almost entirely on the film after casting. It is stated that no bubbles are generated.

  Furthermore, in JP-A-2002-241511, in order to reduce the number of bubbles in the film after drying, that is, as a method for preventing bubbles, (1) a cellulose ester and an organic solvent are mixed in a pressure-resistant dissolution vessel After raising the temperature to near the post-boiling point, (2) after opening the pressure-resistant dissolution vessel to the atmosphere while standing at that temperature for 6 minutes or more, and (3) closing the pressure-resistant dissolution vessel from the atmosphere and setting the boiling point to BP, It is disclosed that the temperature is raised to BP + 20 ° C. to BP + 50 ° C. to obtain a pressurized state, and (4) the dope is subsequently dissolved using the pressurized state.

As described above, the dope using cellulose acylate can exhibit the effect of reducing bubbles in the film by various methods. The present inventor attempted to apply these various methods to a method for producing a film having a glass transition temperature of 250 ° C. or higher and a total light transmittance of 70% or higher. I found it excellent.
Here, “vacuum degassing” is degassing under reduced pressure.

  The vacuum degassing of the dope in the present invention is not particularly limited except that degassing is performed under reduced pressure, but a more preferable method of vacuum degassing is a method of vacuum degassing while boiling, a pressure reduction while giving vibration, The method of deaeration is mentioned. In the case of degassing while boiling, the boiling method may be a method of processing at a temperature exceeding the lowest boiling point of the organic solvent used for the dope, or a method of boiling at an increased degree of vacuum at room temperature. It is also possible to use this method. By performing deaeration while boiling, the deaeration can be efficiently performed in a shorter time. In addition, the flash method known as a method for degassing cellulose acylate dope can be divided into a pressurized flash that pressurizes the feeding container and a reduced pressure flash that reduces the pressure in the receiving container, but the reduced pressure flash results in exposing the dope under reduced pressure. This is included in the vacuum degassing method of the dope in the present invention.

  Further, the vibration of the method of deaeration while applying vibration to the dope is preferably as fine and strong as possible, and it is preferable to perform ultrasonic treatment as the type of deaeration method. Further, as a method of applying vibration, the vibration may be applied from the outside of the pipe or the container, or the ultrasonic vibration element may be directly disposed inside. The vibration frequency of a useful vibration device is preferably 100 Hz to 40 kHz, and particularly preferably 10 to 40 kHz as an ultrasonic vibration element.

  The vacuum degassing method of the dope in the present invention may be a stepwise combination of the above-described methods using boiling and vibration, or may be combined simultaneously. In addition, it is often effective to combine other methods (stirring, warming, standing, pressure flash), which are less effective alone, with vacuum degassing. Among these, the method of degassing under reduced pressure after applying vibration by ultrasonic waves while stirring is particularly preferable because the degassing effect is high and the apparatus is simple.

Moreover, when filtering the dope in this invention, it is preferable to perform the vacuum deaeration of dope after completion | finish of filtration. When performing dope filtration, it is usually easy to entrain air, and when performing dope filtration after deaeration of the dope in the present invention, there is a concern that the effect of deaeration is reduced.
The degree of vacuum when performing vacuum degassing of the dope in the present invention cannot be said more generally than the temperature of the dope and the type of solvent used for the dope, but is preferably 1 to 90000 Pa, more preferably 100 to 80000 Pa, Especially preferably, it is 1000-70000 Pa. Further, in the present invention, as described above, the method of degassing while boiling is preferred, and the preferred pressure in this case is determined by the type of solvent used, the temperature of the dope, and below the vapor pressure of the solvent having the lowest boiling point. Preferably there is. In addition, the concentration can be adjusted by adding a volatile component of the solvent after the degassing of the dope under reduced pressure in the present invention.

(Casting drying process)
Next, the process for casting the solution of the film of the present invention will be described. The casting drying step is a step of casting a dope that has been degassed under reduced pressure onto a support. The solution casting method used in the method for producing a film of the present invention is prepared by preparing a dope in a glass or metal container when performing in a small amount, and performing vacuum degassing after performing filtration as necessary. The film is cast to a desired film thickness using a small die or a doctor blade on a highly smooth substrate such as a glass plate or a metal plate. After casting, primary drying is performed, and the film is peeled off from the support, framed as necessary, and post-dried.

  Moreover, when obtaining a film in large quantities, especially continuously, a solution casting film forming method and a solution casting film forming apparatus conventionally used for producing a cellulose triacetate film can be used. The dope prepared in the dissolving machine (kettle) is filtered, degassed under reduced pressure, etc., and the dope is finally prepared. After that, the dope is sent from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the rotational speed, and the dope is run endlessly from the die (slit) of the pressure die. The dope film (also referred to as a web) is peeled off from the support at a peeling point that is uniformly cast on the support (drum or band) and the support has almost gone around. Both ends of the obtained web are sandwiched between clips, transported by a tenter while keeping the width, dried, then transported by a roll group of a drying device, dried, and wound up to a predetermined length by a winder. The combination of the tenter and the roll group dryer varies depending on the purpose. The surface of the drum or band is preferably finished in a mirror state. The casting and drying methods in the solvent casting method are described in U.S. Pat. Nos. 2,336,310, 2,367,603, 2,492,078, 2,492,977. No. 2,492,978, No. 2,607,704, No. 2,739,069, No. 2,739,070, British Patent No. 640731 No. 736892, JP-B 45-4554, 49-5614, JP-A-60-176834, 60-203430, and 62-1115035. The dope is preferably cast on a drum or band adjusted to an arbitrary surface temperature.

  In the present invention, the obtained dope according to the present invention may be cast as a single layer liquid on a smooth band or drum as a support, or a plurality of the dopes according to the present invention having two or more layers may be cast. May be. When casting a plurality of dopes in the present invention, a film may be produced while casting and laminating the dopes in the present invention from a plurality of casting openings provided at intervals in the traveling direction of the support. For example, methods described in JP-A-61-158414, JP-A-1-122419, JP-A-11-198285 and the like can be applied. Further, the dope according to the present invention may be cast from two or more casting ports simultaneously to form a film. For example, Japanese Patent Publication No. 60-27562, Japanese Patent Publication No. 61-94724, Japanese Patent Publication No. It can be carried out by the methods described in JP-A 61-947245, JP-A 61-104413, JP-A 61-158413, and JP-A 6-134933. Also, a casting method in which the dope according to the present invention having a low viscosity is wrapped with the dope according to the present invention having a low viscosity, and the dope according to the present invention having a high and low viscosity is simultaneously extruded, as described in JP-A-56-162617. But you can.

  Furthermore, in the present invention, using two casting ports, the film cast on the support is peeled off by the first casting port, and the second casting is performed on the side in contact with the support surface. For example, a method described in Japanese Patent Publication No. 44-20235 can be used. The dope in the present invention to be cast may be the same solution or may be a different dope in the present invention, and is not particularly limited. In order to give a plurality of polymer layers of the present invention a function, the dope according to the present invention corresponding to the function may be extruded from each casting port. Furthermore, the dope in the present invention can be cast by simultaneously casting other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing film, etc.).

  The casting method useful in the present invention will be described in detail. A method of uniformly extruding the prepared dope from the pressure die onto the support; the thickness of the dope once cast on the support with a blade is increased. There are a method using a doctor blade for adjustment; a method using a reverse roll coater for adjustment using a reverse rotating roll, etc., and a method using a pressure die is preferred. The pressure die includes a coat hanger type and a T die type, and any of them can be preferably used. In addition to the methods listed here, various known methods for casting a cellulose triacetate solution (for example, JP-A-61-94724, JP-A-61-148013, JP-A-4-85011). No. 4-286611, No. 5-185443, No. 5-185445, No. 6-278149, No. 8-207210, and the like. By setting each condition in consideration of the difference in the boiling point of the solvent to be used, the same effects as described in the respective publications can be obtained.

  The endlessly running support used in the production method of the film of the present invention includes a drum whose surface is mirror-finished by chrome plating and a stainless steel belt (which may be called a band) whose surface is polished by surface polishing. Used. One or more pressure dies used for producing the film of the present invention may be installed above the support. Preferably 1 or 2 groups. When two or more are installed, the amount of dope to be cast may be divided into various ratios for each die, and the dope can be fed to the dies at each ratio from a plurality of precision quantitative gear pumps.

  The drying of the dope on the support according to the film production method of the present invention is generally performed by applying hot air from the surface side of the support (drum or belt), that is, the surface of the web on the support, the drum or A method of applying hot air from the back of the belt, a liquid heat transfer method of controlling the surface temperature by contacting the temperature-controlled liquid from the back of the belt or drum opposite the dope casting surface and heating the drum or belt by heat transfer However, the back surface liquid heat transfer method is preferable. The surface temperature of the support before casting is not particularly limited as long as it is not higher than the boiling point of the solvent used for the dope. However, in order to promote drying and to lose fluidity on the support, the temperature may be set to 1 to 10 ° C lower than the boiling point of the lowest boiling solvent used. preferable. Further, when a plurality of solvents having different boiling points are used, the temperature may be increased in multiple steps or continuously. On the other hand, the number of bubbles generated in the film tends to be reduced by setting the temperature to 20 ° C. or more lower than the boiling point of the solvent having the lowest boiling point. This can be inferred that the bubble removal is promoted by lowering the drying speed of the film, and it is difficult to achieve both productivity improvement.

  The polymer film in the present invention formed on the support is peeled from the support. At this time, the maximum value of the peeling load (maximum peeling load) is preferably 1 to 30 g / cm, more preferably 1 to 28 g / cm, and further preferably 3 to 25 g / cm. In addition, the time from when the dope is cast on the support to the start of peeling is preferably 30 seconds to 600 seconds, more preferably 30 seconds to 400 seconds, and more preferably 30 seconds to 240 seconds. Is more preferable.

  In the drying process after peeling from the support, the film tends to shrink in the width direction by evaporation of the solvent. For this reason, shrinkage becomes large, so that it dries at high temperature. Drying while suppressing this shrinkage as much as possible is preferable for improving the flatness of the finished film. From this point of view, for example, a method of drying the entire drying process or a part of the process as shown in Japanese Patent Application Laid-Open No. 62-46625 while holding the width at both ends of the web with a clip in the width direction (tenter method) ) Is preferred.

  The drying step in the film production method of the present invention is preferably dried by increasing the temperature in multiple stages. The initial drying temperature varies depending on the boiling point of the organic solvent used, but is preferably 40 to 250 ° C, more preferably 70 to 220 ° C. Furthermore, in order to remove a residual solvent, it is preferable to dry at a temperature higher than the initial drying temperature, and it is dried in a temperature range from 50 ° C. to the glass transition temperature of the film of the present invention. In that case, it may dry with the high temperature wind which changed temperature one by one, an infrared heater may be used, and both can also be used together. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from casting to stripping. The drying temperature, the amount of drying air, and the drying time vary depending on the solvent used, and may be appropriately selected according to the type and combination of the solvents used. The amount of residual solvent in the final finished film is preferably 2% by mass or less, more preferably 0.4% by mass or less, and particularly preferably 0.1% by mass or less. Moreover, drying of a film may be performed under an inert gas stream as needed, and may be performed under reduced pressure.

  In the present invention, in order to improve its physical properties, it may be positively stretched in the width direction. For example, JP-A-62-115035, JP-A-4-152125, JP-A-4284221, The methods described in JP-A-4-298310 and JP-A-11-48271 can be applied. The film is generally stretched at a temperature 10 to 20 ° C. higher than Tg (glass transition temperature). However, the film of the present invention has a high glass transition temperature and is heated to a temperature higher than the glass transition temperature. Decomposition may begin. In such a case, in the present invention, it is particularly effective to stretch the film of the present invention by treatment during drying. That is, by performing stretching in a state where the apparent glass transition temperature containing the solvent is low, stretching can be performed at a temperature at which the polymer does not decompose. As the stretching method, for example, in the case of stripping, the film is stretched by adjusting the speed of the film transport roller so that the film winding speed is higher than the film stripping speed. In the case of drying after peeling, the film is stretched by increasing the transport speed of the transport roller at the transport destination relative to the transport speed of the transport roller on the near side in the transport direction. Further, the film can be stretched in the width direction by conveying the film while holding the film with a tenter and gradually increasing the width of the tenter.

  The stretch ratio of the film (the ratio of the length after stretching relative to the original length) is preferably 1.03 to 3 times, more preferably 1.05 to 2.5 times, and more preferably 1.05 to 1.8 times. At this time, the stretching direction may be the casting direction, may be stretched in a direction perpendicular to the casting direction, or may be stretched in both directions depending on circumstances. At this time, stretching may be performed simultaneously, or stretching in one direction and then stretching in another direction. These steps from casting to post-drying may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas.

  The winder related to the production of the polymer film in the present invention may be a commonly used winder such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. Can be wound up. The thickness of the polymer film in the present invention (after drying) varies depending on the purpose of use, but is usually preferably in the range of 20 to 500 μm, more preferably in the range of 30 to 250 μm, and particularly preferably in the range of 30 to 150 μm. Most preferred. The film thickness may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the support speed, and the like so as to obtain a desired thickness.

  The stretching speed is preferably 5% / min to 1000% / min, and more preferably 10% / min to 500% / min. The stretching is preferably performed by a heat roll or / and a radiant heat source (such as an IR heater) or warm air. Moreover, you may provide a thermostat in order to improve the uniformity of temperature. When performing uniaxial stretching by roll stretching, it is preferable that L / W which is ratio of the distance between rolls (L) and film width (W) is 2.0-5.0. Furthermore, in order to prevent foaming of the tenter-dried web, improve detachability, and prevent dust generation, the width of the dryer should be set so that the hot air and heat source of the dryer do not hit the edges of the web in the dryer. However, it is also preferable that the length is shorter than the width of the web. Moreover, you may install a shielding board inside web both ends so that a hot air and a heat source may not hit a holding | maintenance part of a tenter.

  What is necessary is just to select the draw ratio which should make a stretched film the predetermined | prescribed thickness. Further, by stretching, it may be preferable that an improvement in planarity such as flatness can be achieved. Furthermore, in order to make the thickness unevenness smaller, by providing a gradient in the width direction of the stretching temperature, it may be possible to achieve more uniform stretching than stretching at a constant temperature.

  The thickness unevenness of the film of the present invention is preferably 0% to 5% in both the casting direction and the width direction, more preferably 0% to 3%, and still more preferably 0% to 1%. The film of the present invention preferably has a low dimensional change rate. In particular, when used for the purpose of installing various functional layers as a display substrate, the required level of dimensional change is high, preferably 200 ° C. (more preferably 250 ° C., particularly preferably 300 ° C.), and 5 hours heat treatment. In this case, the vertical and horizontal dimensional change rates are preferably ± 0.1% or less, more preferably ± 0.01% or less, and particularly preferably ± 0.005% or less.

  In order to reduce the dimensional change rate of the film of the present invention, it is effective to perform heat treatment in advance. The heating temperature in this case can be arbitrarily selected within the temperature range of 150 ° C. to the glass transition temperature or less, although it depends on the application to be used and the level of the required dimensional change rate. The heating time is shorter as the temperature is higher, and is determined by the level of the required dimensional change rate and the heat treatment temperature. On the other hand, the heat treatment performed here is performed in order to eliminate the internal stress remaining in the film in the film drying process or the stretching process performed as necessary, and the film shrinks by the heat treatment. Therefore, if the film is contracted rapidly, the flatness of the film may be deteriorated, so care must be taken. In such a case, as the heat treatment method in the film production method of the present invention, the heat treatment is performed by fixing the end portion so as not to cause rapid shrinkage on the dried film, and then the end portion is not fixed. The method of performing the heat treatment in two stages to complete the shrinkage is particularly effective as a method capable of reducing the dimensional change rate without deteriorating the flatness. In the heat treatment, the cut film can be processed one by one, or the film can be continuously heat-treated while winding the film into a roll. The cut film is fixed to a metal frame with a clip or the like, and after the first heat treatment is performed, the clip is removed and the heat treatment is performed again, whereby the two-stage heat treatment described above can be performed. In the case of continuous heat treatment, while maintaining the width size while fixing with the width direction tenter clip or shrinking to the desired shrinkage amount, the conveyance direction is adjusted by adjusting the rotation speed of the conveyance roll for each roll. The same effect as that of fixing can be obtained, and the first heat treatment can be performed while suppressing rapid contraction. After that, the second heat treatment is either a method in which the tenter clip is released and all conveyance roll rotation speeds are made the same, or a method in which the roll after winding is directly heat-treated. You can choose.

  Here, although the cooling temperature after the said heat processing changes with process temperature and film thickness, Preferably it is 0-40 degreeC. At this time, if the temperature difference between the cooling medium such as air that cools the front and back surfaces of the film is too large, the difference in thermal shrinkage between the front and back surfaces of the resulting film will increase, and the film will be distorted and warped easily during heating. In some cases, the deformation becomes large. Considering such points, it is preferable that the temperature difference between the cooling medium such as air for cooling the front and back surfaces of the film is small. However, in order to achieve the object of the present invention, the temperature difference is adjusted within 5 ° C. It is preferable.

  By producing the film of the present invention by the above method, a film having high heat resistance and high transmittance, few defects such as bubbles and foreign matters, and excellent flatness and dimensional stability can be obtained with high productivity. The film of the present invention preferably has higher heat resistance, and the glass transition temperature is 250 ° C. or higher, preferably 300 ° C. or higher, more preferably 350 ° C. or higher. The glass transition temperature can be measured by any known method such as DSC, TMA, or viscoelasticity measurement, and TMA measurement is the simplest and preferred measurement method. The film of the present invention preferably has a high transmittance, and the total light transmittance is 70% or more, preferably 75% or more, more preferably 80% or more. The total light transmittance can be measured using a direct reading type haze computer HGM-2DP manufactured by Suga Test. Further, the haze of the film can be measured simultaneously with the total light transmittance, and the preferred haze is 0.8% or less, more preferably 0.5% or less.

  The production of the film of the present invention is preferably carried out by continuously casting the solution onto a rotating drum or band, stripping and drying, and winding it into a roll. At this time, when the film is mechanically conveyed, it is preferable that the mechanical strength of the film is high. The preferable mechanical strength varies depending on the conveying device and cannot be generally specified, but as a guide, the breaking stress and the breaking elongation obtained from the tensile test of the film can be used. A preferable breaking stress is 50 MPa or more, more preferably 80 MPa or more, and further preferably 100 MPa or more. Since the elongation at break varies depending on the sample preparation conditions and the like, the reliability is slightly lower than the break stress, but is preferably 5% or more, more preferably 10% or more, and even more preferably 15% or more.

(Modification of the film of the present invention)
Next, the preferable aspect in the case of providing the function further about the film of this invention is described. First, the film surface treatment method of the present invention will be described.
The film of the present invention can achieve improved adhesion between the film of the present invention and various functional layers by optionally performing a surface treatment. For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment refers to so-called low temperature plasma that occurs under a low pressure gas of 10 ^{−3 to} 20 Torr (0.13 to 2700 Pa), but may be a glow discharge treatment under atmospheric pressure.

First, glow discharge treatment under low pressure is performed in US Pat. Nos. 3,462,335, 3,761,299, 4,072,769, and British Patent 891,469. It is described in the specification. In addition, a specific gas such as an inert gas, nitrogen oxides, or an organic compound gas is also introduced. When the surface of the water vapor barrier film is subjected to glow discharge treatment, it may be at atmospheric pressure or under reduced pressure. Furthermore, it may be carried out while introducing various gases such as oxygen, nitrogen, helium or argon and water into the atmosphere of the glow discharge treatment. The degree of vacuum during the glow discharge treatment is preferably 0.005 to 20 Torr (0.6666 to 2700 Pa), and more preferably 0.02 to 2 Torr (2.666 to 266.6 Pa). The voltage is preferably between 500 and 5000V, more preferably between 500 and 3000V. The discharge frequency to be used is from direct current to several thousand MHz, more preferably 50 Hz to 20 MHz, and further preferably 1 KHz to 1 MHz. The discharge treatment intensity is preferably 0.01 KV · A · min / m ^{2 to 5} KV · A · min / m ² , more preferably 0.15 KV · A · min / m ^{2 to 1} KV · A · min / m ² . is there.

Next, as the surface treatment of the film of the present invention, an ultraviolet irradiation method is also preferably used in the present invention. The mercury lamp used is a high-pressure mercury lamp made of a quartz tube and preferably has an ultraviolet wavelength of 180 to 380 nm. As for the method of ultraviolet irradiation, a high pressure mercury lamp with a dominant wavelength of 365 nm can be used as long as the surface temperature of the film of the present invention rises to around 150 ° C. if there is no problem in the performance of the support. When low-temperature treatment is required, a low-pressure mercury lamp having a dominant wavelength of 254 nm is preferable. Ozone-less high-pressure mercury lamps and low-pressure mercury lamps can also be used. With regard to the amount of processed light, the greater the amount of processed light, the better the adhesive force between the film of the present invention and the adherend layer, but the problem arises that the support becomes colored and the support becomes brittle as the amount of light increases. Therefore, a high-pressure mercury lamp having a main wavelength of 365 nm has a good irradiation light quantity of 20 to 10000 (mJ / cm ² ), more preferably 50 to 2000 (mJ / cm ² ). In the case of low-pressure mercury lamp for a 254nm main wavelength, the irradiation light amount 100~10000 (mJ / cm ²⁾ C., more preferably 300~1500 (mJ / cm ^2).

Next, corona discharge treatment can also be preferably used as the surface treatment of the film of the present invention. As the corona discharge treatment apparatus, a solid state corona treatment machine manufactured by Pillar, a LEPEL type surface treatment machine, a VETAPHON type treatment machine, or the like can be used. Further, the corona discharge treatment can be performed in air at normal pressure. The discharge frequency during the treatment is 5 to 40 KV, more preferably 10 to 30 KV, and the waveform is preferably an AC sine wave. The gap clearance between the electrode and the dielectric roll is 0.1 to 10 mm, more preferably 1.0 to 2.0 mm. The discharge is processed above a dielectric support roller provided in the discharge zone, and the treatment amount is 0.3 to 0.4 KV · A · min / m ² , more preferably 0.34 to 0.38 KV · A ·. Min / m ² .

Next, flame treatment is described. The gas used for the flame treatment may be natural gas, liquefied propane gas, or city gas, but the mixing ratio with air is important. A preferable mixing ratio of natural gas / air is 1/6 to 1/10, preferably 1/7 to 1/9 by volume. In the case of liquefied propane gas / air, 1/14 to 1/22, preferably 1/16 to 1/19, and in the case of city gas / air, 1/2 to 1/8, preferably 1/3 to 1. / 7. The flame treatment amount is preferably 1 to 50 Kcal / m ² , more preferably 3 to 20 Kcal / m ² .

  Next, the alkali saponification treatment will be specifically described. The film surface of the present invention is preferably immersed in an alkaline solution, then neutralized with an acidic solution, washed with water and dried. Examples of the alkaline solution include a potassium hydroxide solution and a sodium hydroxide solution, and the concentration of hydroxide ions is preferably 0.1 mol / L to 4.0 mol / L, and 0.5 mol / L to 3. More preferably, it is 5 mol / L. The alkaline solution temperature is preferably in the range of room temperature to 90 ° C, more preferably 40 ° C to 70 ° C. Next, the film is generally washed with water, then passed through an acidic aqueous solution, and then washed with water to obtain a surface-treated film.

  At this time, the acid is hydrochloric acid, nitric acid, sulfuric acid, acetic acid, formic acid, chloroacetic acid, oxalic acid, etc., and its concentration is preferably 0.01 mol / L to 3.0 mol / L, 0.05 mol / L More preferably, it is -2.0 mol / L. The alkali saponification time is preferably 20 seconds to 600 seconds, more preferably 30 seconds to 300 seconds, and particularly preferably 40 seconds to 210 seconds. The neutralization is preferably carried out for 20 seconds to 600 seconds, more preferably 30 seconds to 250 seconds, and particularly preferably 40 seconds to 180 seconds. Further, the washing with water is preferably performed for 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds, and particularly preferably 40 seconds to 210 seconds.

  In order to bond the film of the present invention and the functional layer, after surface activation treatment, a method of directly forming the functional layer on the film of the present invention to obtain an adhesive force, and once some surface treatment There is a method in which an undercoat layer (adhesive layer) is provided and a functional layer is formed thereon after or after surface treatment. The undercoat layer may be a so-called multi-layer method in which a layer that adheres well to the support is provided as the first layer, and a second undercoat layer that adheres well to the functional layer is applied thereon as the second layer.

The undercoat layer optionally applied to the film of the present invention may contain inorganic or organic fine particles as a matting agent to such an extent that the transparency of the functional layer is not substantially impaired. Silica (SiO ₂ ), titanium dioxide (TiO ₂ ), calcium carbonate, magnesium carbonate and the like can be used as the inorganic fine particle matting agent. Examples of the organic fine particle matting agent include polymethyl methacrylate, cellulose acetate propionate, polystyrene, a treatment solution-soluble one described in US Pat. No. 4,142,894, US Pat. , 396, 706, and the like. These fine particle matting agents preferably have an average particle size of 0.01 to 10 μm. More preferably, it is 0.05-5 micrometers. Moreover, the content is preferably 0.5 to 600 mg / m ² , more preferably 1 to 400 mg / m ² . The undercoat liquid is a generally well-known coating method, such as dip coating, air knife coating, curtain coating, roller coating, wire bar coating, gravure coating, slide coating, or U.S. Pat. It can apply | coat by the extrusion coat method using the hopper as described in 681,294 specification.

  Depending on the application, the surface of the film of the present invention may have an undercoat layer, a smoothing layer for smoothing the surface, a hard coat layer for imparting scratch resistance, an ultraviolet absorbing layer for enhancing light resistance, and film transport. Various known functional layers can be provided depending on the purpose such as a surface roughened layer for improving the properties.

The film of the present invention is excellent in heat resistance and transparency and can be used for various display substrates. In this case, a transparent conductive layer, a gas barrier layer and the like are formed, and a TFT, an organic EL element, etc. are formed on the film of the present invention. It can also be formed.
As the transparent conductive layer, a known metal film, metal oxide film, or the like can be applied. Among these, a metal oxide film is preferable from the viewpoint of transparency, conductivity, and mechanical characteristics. For example, metal oxide films such as indium oxide, cadmium oxide and tin oxide added with tin, tellurium, cadmium, molybdenum, tungsten, fluorine, zinc, germanium, etc. as impurities, zinc oxide, titanium oxide, etc. added aluminum as impurities Can be mentioned. Among them, an indium oxide thin film mainly composed of tin oxide and containing 2 to 15% by mass of zinc oxide is excellent in transparency and conductivity, and is preferably used.

  The transparent conductive layer can be formed by any method as long as the target thin film can be formed. For example, a material from the gas phase such as sputtering, vacuum deposition, ion plating, and plasma CVD can be used. A vapor phase deposition method in which a film is deposited to form a film is suitable, and a film can be formed by the methods described in Japanese Patent No. 3430344, Japanese Patent Application Laid-Open No. 2002-322561, and Japanese Patent Application Laid-Open No. 2002-361774. Among these, the sputtering method is preferable from the viewpoint that particularly excellent conductivity and transparency can be obtained.

  A preferable degree of vacuum of the sputtering method, vacuum deposition method, ion plating method, and plasma CVD method is 0.133 mPa to 6.65 Pa, more preferably 0.665 mPa to 1.33 Pa. Before providing such a transparent conductive layer, it is preferable to subject the base film to a surface treatment such as plasma treatment (reverse sputtering) or corona treatment. Moreover, you may heat up to 50-200 degreeC during providing the transparent conductive layer.

  The thickness of the transparent conductive layer is preferably 20 to 500 nm, and more preferably 50 to 300 nm.

  Further, the surface electrical resistance measured at 25 ° C. and 60% RH (relative humidity) of the transparent conductive layer is preferably 0.1 to 200Ω / □, more preferably 0.1 to 100Ω / □, More preferably, it is 0.5-60Ω / □. The light transmittance of the transparent conductive layer is 80% or more, more preferably 83% or more, and still more preferably 85% or more.

  The film of the present invention is preferably provided with a gas barrier layer in order to suppress gas permeability. Preferred gas barrier layers include, for example, metal oxides composed mainly of one or more metals selected from the group consisting of silicon, aluminum, magnesium, zinc, zirconium, titanium, yttrium, and tantalum, silicon, aluminum, boron Metal nitrides or mixtures thereof. Among these, the main component is silicon oxide having a ratio of the number of oxygen atoms to the number of silicon atoms of 1.5 to 2.0 in terms of gas barrier properties, transparency, surface smoothness, flexibility, film stress, cost, and the like. Metal oxide is good.

  These inorganic gas barrier layers can be produced, for example, by a vapor deposition method in which a material is deposited in a vapor phase such as sputtering, vacuum deposition, ion plating, or plasma CVD to form a film. Among these, the sputtering method is preferable from the viewpoint that particularly excellent gas barrier properties can be obtained. Moreover, you may heat up to 50-200 degreeC during providing the gas barrier layer.

  The film thickness of the gas barrier layer is preferably 10 to 300 nm, and more preferably 30 to 200 nm.

  The gas barrier layer may be provided on the same side or the opposite side of the transparent conductive layer, or may be provided on both sides.

Gas barrier film having a gas barrier layer is preferably a water vapor permeability as measured at 40 ° C. · 100% relative humidity is 0~5g / m ² · day, it is 0~1g / m ² · day Is more preferably 0 to 0.5 g / m ² · day. The oxygen permeability was measured at 40 ° C. · 90% RH is preferably from ^{0~1ml / m 2 · day · atm} , more preferably from 0~0.7ml / m ² · day · atm 0 to 0.5 ml / m ² · day · atm is more preferable.

  In the film of the present invention, it is preferable to provide a defect compensation layer adjacent to the gas barrier layer for the purpose of improving the barrier property. The defect compensation layer is (1) a method using an inorganic oxide layer produced using a sol-gel method as described in US Pat. No. 6,171,663 and Japanese Patent Application Laid-Open No. 2003-94572, and (2) US Pat. It can be produced by a method using an organic material layer as described in the specification of 64136645 and 64163645. Further, as described in the above-mentioned document, the defect compensation layer is prepared by a method of curing under ultraviolet light or electron beam after vacuum deposition, or a method of curing with heating, electron beam, ultraviolet light or the like after coating. It is preferable to do. When the coating method is used, various conventionally used coating methods such as spray coating, spin coating, and bar coating can be used.

(Image display element)
The film of the present invention can be used as a substrate for a thin film transistor (TFT) display element. Examples of the method for producing the TFT array include the method described in JP-T-10-512104. Further, these substrates may have a color filter for color display. The color filter may be produced by any method, but is preferably produced by a photolithography technique.

  The film of this invention can be used for an image display element, after providing various functional layers as needed. Here, it does not specifically limit as an image display element, A conventionally well-known thing can be used. Moreover, the flat panel display excellent in display quality can be produced using the film of this invention. Flat panel displays include liquid crystals, plasma displays, electroluminescence (EL), fluorescent display tubes, light-emitting diodes, etc. In addition to these, they are used as substrates that replace glass-type display substrates that have conventionally used glass substrates. be able to. Furthermore, the film of the present invention can be used for applications such as solar cells and touch panels. The solar cells are applied to those described in JP-A-9-148606, JP-A-11-288745, problems and countermeasures for the all-plasticization of new organic solar cells (2004, published by the Japan Society for Information Technology). it can. The touch panel can be applied to those described in JP-A-5-127822, JP-A-2002-48913, and the like.

  When the film of the present invention is used for liquid crystal display applications, it is preferably an amorphous polymer in order to achieve optical uniformity. The birefringence is preferably small, and the in-plane retardation (Re) is preferably 50 nm or less, more preferably 30 nm or less, and further preferably 15 nm or less. In order to obtain a film having a small birefringence using only the polymer in the present invention, the solvent and the drying conditions at the time of solution casting can be appropriately adjusted, or can be adjusted by stretching as necessary. Furthermore, for the purpose of controlling retardation (Re) and its wavelength dispersion, resins having different signs of intrinsic birefringence can be combined, or resins having large (or small) wavelength dispersion can be combined. In addition, the film of the present invention can be suitably used for the purpose of controlling retardation (Re) and improving gas permeability and mechanical properties, such as lamination of different resins. Further, phase difference compensation can be performed by using a known retardation plate in combination.

  On the other hand, the film of the present invention can also be used as a retardation plate by controlling the optical anisotropy. In this case, the birefringence does not necessarily have to be small, and it is only necessary to have a desired birefringence. As a method for obtaining the desired birefringence, any known method such as stretching the film of the present invention, mixing a compound having birefringence, coating, or the like can be used.

  When used in a reflection type liquid crystal display device, it is composed of a lower substrate, a reflective electrode, a lower alignment film, a liquid crystal layer, an upper alignment film, a transparent electrode, an upper substrate, a λ / 4 plate, and a polarizing film in order from the bottom. Of these, the film of the present invention may be used as a λ / 4 plate, a polarizing film protective film, or other retardation plate (for example, a viewing angle compensation film) by adjusting optical characteristics, but as a substrate from the viewpoint of heat resistance. It is preferable to use as a transparent electrode and an upper substrate with an alignment film from the viewpoint of transparency. Moreover, a gas barrier layer, TFT, etc. can also be provided as needed. In the case of color display, it is preferable to further provide a color filter layer between the reflective electrode and the lower alignment film, or between the upper alignment film and the transparent electrode.

  When used in a transmissive liquid crystal display device, the backlight, polarizing plate, λ / 4 plate, lower transparent electrode, lower alignment film, liquid crystal layer, upper alignment film, upper transparent electrode, upper substrate, λ / 4 are sequentially arranged from the bottom. It consists of a plate and a polarizing film. Of these, the film of the present invention may be used as a λ / 4 plate, a protective film for a polarizing film, or other retardation plate (for example, a viewing angle compensation film) by adjusting optical characteristics, but is a substrate from the viewpoint of heat resistance. And is preferably used as a transparent electrode and a substrate with an alignment film. Moreover, a gas barrier layer, TFT, etc. can also be provided as needed. In the case of color display, it is preferable to further provide a color filter layer between the lower transparent electrode and the lower alignment film, or between the upper alignment film and the transparent electrode.

  The liquid crystal cell is not particularly limited, but TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-ferroelectric Liquid Crystal), OCB (Optically Compensated Bend), STN (Super Twisted Nematic) ), VA (Vertically Aligned) and HAN (Hybrid Aligned Nematic) have been proposed. There has also been proposed a display mode in which the above display mode is orientation-divided. The film of the present invention is effective in any display mode liquid crystal display device. Further, it is effective in any of a transmissive type, a reflective type, and a transflective liquid crystal display device.

  These are JP-A-2-176625, JP-B-7-69536, MVA (SID97, Digest of tech. Papers (Preliminary Collection) 28 (1997) 845), SID99, Digest of tech. Papers (Preliminary Collection) 30. (1999) 206, JP-A-11-258605, SURVAIVAL (Monthly Display, Vol. 6, No. 3 (1999) 14), PVA (Asia Display 98, Proc. Of the-18th-Inter. Display res. Conf. (Preliminary Collection (1998) 383), Para-A (LCD / PDP Iternational`99), DDVA (SID98, Digest of tech. Papers (Preliminary Collection) 29 (1998) 838), EOC (SID98, Digest of tech Papers 29 (1998) 319), PSHA (SID98, Digest of tech. Papers 29 (1998) 1081), RFFMH (Asia Display 98, Proc. Of the-18th-Inter. Display res Conf. (Preliminary Collection) (1998) 375), HMD (SID98, Digest of tech. Papers (Preliminary Collection) 29 (1998) 702), JP-A-10-123478, International Publication W098 / 48320, Patent No. 3022477 And it is described in International Publication WO00 / 65,384 Patent Publication.

The film of the present invention is provided with a gas barrier layer and a TFT as necessary, and can be used for organic EL display applications as a substrate with a transparent electrode.
As a specific layer structure as the organic EL display element, anode / light emitting layer / transparent cathode, anode / light emitting layer / electron transport layer / transparent cathode, anode / hole transport layer / light emitting layer / electron transport layer / transparent cathode , Anode / hole transport layer / light emitting layer / transparent cathode, anode / light emitting layer / electron transport layer / electron injection layer / transparent cathode, anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron Examples include injection layer / transparent cathode.

  In the organic EL device in which the film of the present invention can be used, a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 40 volts) or a direct current is applied between the anode and the cathode. Thus, light emission can be obtained.

  Regarding driving of these organic EL elements, JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234585, The methods described in Kaihei 8-24047, U.S. Pat. Nos. 5,828,429, 6023308, and Japanese Patent No. 2784615 can be used.

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

[Measurement method of film characteristic values]
The characteristic values of the film were measured as follows.
<Film thickness (film thickness)>
It measured with the dial-type thickness gauge (Anritsu Co., Ltd. product, K402B).
<Total light transmittance of film>
The total light transmittance of the film was measured using “Direct Reading Haze Computer HGM-2DP” manufactured by Suga Test Instruments.
<Glass transition temperature (Tg)>
A film sample (0.5 cm × 2.0 cm piece) was prepared, and the thermal deformation start temperature obtained by the tensile load method of TMA (manufactured by Rigaku Corporation, TMA8310) under the condition of a tensile load of 100 mN was the glass transition of the film. Measured as temperature.

<Number of bubbles in film>
The number of bubbles in a film sample of about 1 m ² (32 cm × 100 cm × 3 sheets) was visually counted under crossed Nicols to obtain the number of bubbles in the film.
<Number of foreign objects on film>
The film sample was observed 150 times with an optical microscope, and the number of foreign matters having a diameter of 5 μm or more in 70 mm ² (observation of 50 points of 1.4 mm ² ) was counted, and this was taken as the number of foreign matters on the film.
<Dimensional change rate of film>
A film sample (0.5 cm × 2.0 cm piece) was prepared, and under the condition of a tensile load of 100 mN, an arbitrary temperature (the glass transition temperature of the film −50 by the tensile load method of TMA (manufactured by Rigaku Corporation, TMA8310)). The amount of dimensional change when heated at 5 ° C for 5 hours was measured, and the value obtained by dividing by the sample length before measurement was taken as the dimensional change rate of the film. Expressed as a value).

<Flatness of film>
A fluorescent lamp was imprinted on the film sample and observed with the naked eye. The film was judged as follows from the distortion of the fluorescent lamp image, and the film was flat.
○: There is almost no distortion of the fluorescent lamp image.
Δ: Some distortion of the fluorescent lamp image is seen.
X: Most of the distortion of the fluorescent lamp image is seen.

[Comparative Example 1]
1. 1. Film production method 1-1. Film formation of cellulose triacetate film (the method described in Example 1 of JP-A-2003-200445)
(Method of reducing pressure during dope preparation)
A solvent and plasticizer mixed solution having the following composition is prepared in a 1 L glass bottle having a stirring blade connected with a vacuum pipe, and the pressure inside the glass bottle is set to 90000 Pa, and the cellulose triacetate powder (average size 2 mm) is gradually added while stirring well. The total amount was 920 g. After the addition, the mixture was left at room temperature (25 ° C.) for 1 hour to swell the cellulose triacetate. Next, the glass bottle was cooled in a methanol / dry ice mixed bath at −70 ° C. for 30 minutes to dissolve the cellulose triacetate, and then heated to 50 ° C. to filter paper with an average pore diameter of 40 μm (manufactured by Toyo Filter Paper Co., Ltd., “# 63 ”) and filtered under pressure at a pressure of 0.5 MPa to obtain a cellulose triacetate dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. This cellulose triacetate dope was cast on a glass substrate using a small casting die having a width of 40 cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. Furthermore, it was made to dry at 140 degreeC for 30 minutes, and the film sample (sample 101) was obtained.
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
Cellulose triacetate 28 parts by mass (substitution degree 2.83, viscosity average polymerization degree 320, water content 0.4 mass%,
6% by weight viscosity in methylene chloride solution 305 mPa · s)
-75 parts by weight of methyl acetate-10 parts by weight of cyclopentanone-5 parts by weight of acetone-5 parts by weight of methanol-5 parts by weight of plasticizer-1 part by weight of plasticizer A (dipentaerythritol hexaacetate)-Plasticizer B (triphenylphosphine) 1 part by weight

[Comparative Example 2]
1-2. Film formation of cellulose triacetate film (the method described in Example 2 of JP-A-2003-200445)
(Method of heating and leaving the dope after filtration)
Prepare a solvent and plasticizer mixed solution of the following composition in a 1 L glass bottle with stirring blades, gradually add cellulose triacetate powder (average size 2 mm) while stirring well, and charge to a total of 920 g. It is. After the addition, the mixture was left at room temperature (25 ° C.) for 1 hour to swell the cellulose triacetate. Next, the glass bottle was cooled in a methanol / dry ice mixed bath at −70 ° C. for 30 minutes to dissolve the cellulose triacetate, and then heated to 50 ° C. to filter paper with an average pore diameter of 40 μm (manufactured by Toyo Filter Paper Co., Ltd., “# 63 ”) and pressure filtered at a pressure of 0.5 MPa to obtain a cellulose triacetate dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. Thereafter, this cellulose triacetate dope was allowed to stand at 50 ° C. for 2.5 hours, and then cast on a glass substrate using a small casting die having a width of 40 cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (Sample 102).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
Cellulose triacetate 28 parts by mass (substitution degree 2.83, viscosity average polymerization degree 320, water content 0.4 mass%,
6% by weight viscosity in methylene chloride solution 305 mPa · s)
-75 parts by weight of methyl acetate-10 parts by weight of cyclopentanone-5 parts by weight of acetone-5 parts by weight of methanol-5 parts by weight of plasticizer-1 part by weight of plasticizer A (dipentaerythritol hexaacetate)-Plasticizer B (triphenylphosphine) 1 part by weight

[Comparative Example 3]
1-3. Film formation of cellulose triacetate film (the method described in Example 4 of JP-A-2003-200445)
(Method of decompressing the dope after filtration)
Prepare a solvent and plasticizer mixed solution of the following composition in a 1 L glass bottle with stirring blades, gradually add cellulose triacetate powder (average size 2 mm) while stirring well, and charge to a total of 920 g. It is. After the addition, the mixture was left at room temperature (25 ° C.) for 1 hour to swell the cellulose triacetate. Next, the glass bottle was cooled in a methanol / dry ice mixed bath at −70 ° C. for 30 minutes to dissolve the cellulose triacetate, and then heated to 50 ° C. to filter paper with an average pore diameter of 40 μm (manufactured by Toyo Filter Paper Co., Ltd., “# 63 ”) and pressure filtered at a pressure of 0.5 MPa to obtain a cellulose triacetate dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. While this cellulose triacetate dope was put in a glass bottle, it was put into a vacuum apparatus (VOS-301SD manufactured by EYELA) equipped with a vacuum pipe and the pressure was reduced to 4000 to 5000 Pa, and the generation of bubbles was visually confirmed. Then, it cast on the glass substrate using the small casting die of width 40cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (sample 103).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
Cellulose triacetate 28 parts by mass (substitution degree 2.83, viscosity average polymerization degree 320, water content 0.4 mass%,
6% by weight viscosity in methylene chloride solution 305 mPa · s)
-75 parts by weight of methyl acetate-10 parts by weight of cyclopentanone-5 parts by weight of acetone-5 parts by weight of methanol-5 parts by weight of plasticizer-1 part by weight of plasticizer A (dipentaerythritol hexaacetate)-Plasticizer B (triphenylphosphine) 1 part by weight

[Comparative Example 4]
1-4. PF-1 film formation (method without degassing)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and the above-mentioned PF-1 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor. After dissolving PF-1, it was heated to 50 ° C. and filtered with an average pore size of 40 μm (manufactured by Toyo Roshi Kaisha, Ltd., “# 63 ]) And pressure filtered at a pressure of 0.5 MPa to obtain a PF-1 dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. This PF-1 dope was cast on a glass substrate using a small casting die having a width of 40 cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (sample 104).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Comparative Example 5]
1-5. Film formation of PF-1 (Method of drying at low temperature without degassing)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and PF-1 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor. After dissolving PF-1, it was heated to 50 ° C. and filtered with an average pore size of 40 μm (manufactured by Toyo Roshi Kaisha, Ltd., “# 63 ]) And pressure filtered at a pressure of 0.5 MPa to obtain a PF-1 dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. This PF-1 dope was cast on a glass substrate using a small casting die having a width of 40 cm. After casting, the film was dried at 12 ° C. for 10 minutes and at 40 ° C. for 10 minutes while blowing with a dew point of 6 ° C., and then the film was peeled off from the glass substrate, and a metal frame having an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (Sample 105).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Comparative Example 6]
1-6. Film formation of PF-1 (Method of reducing pressure during dope preparation)
In a 1 L glass bottle having a stirring blade connected to a decompression pipe, a solvent having the following composition was prepared, the pressure in the glass bottle was set to 90000 Pa, and PF-1 powder (average size 1 mm) was gradually added while stirring well, The whole was charged to 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor. After dissolving PF-1, it was heated to 50 ° C. and filtered with an average pore size of 40 μm (manufactured by Toyo Roshi Kaisha, Ltd., “# 63 ]) And pressure filtered at a pressure of 0.5 MPa to obtain a PF-1 dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour f. This PF-1 dope was cast on a glass substrate using a small casting die having a width of 40 cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (sample 106).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Comparative Example 7]
1-7. Film formation of PF-1 (Method of heating and standing the dope after filtration)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and PF-1 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor. After dissolving PF-1, it was heated to 50 ° C. and filtered with an average pore size of 40 μm (manufactured by Toyo Roshi Kaisha, Ltd., “# 63 ]) And pressure filtered at a pressure of 0.5 MPa to obtain a PF-1 dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. Thereafter, this PF-1 dope was allowed to stand at 50 ° C. for 2.5 hours, and then cast on a glass substrate using a small casting die having a width of 40 cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (Sample 107).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Comparative Example 8]
1-8. Film formation of PF-1 (Method of reducing pressure during dope preparation, heat shrinking treatment)
In a 1 L glass bottle having a stirring blade connected to a decompression pipe, a solvent having the following composition was prepared, the pressure in the glass bottle was set to 90000 Pa, and PF-1 powder (average size 1 mm) was gradually added while stirring well, The whole was charged to 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor. After dissolving PF-1, it was heated to 50 ° C. and filtered with an average pore size of 40 μm (manufactured by Toyo Roshi Kaisha, Ltd., “# 63 ]) And pressure filtered at a pressure of 0.5 MPa to obtain a PF-1 dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. This PF-1 dope was cast on a glass substrate using a small casting die having a width of 40 cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. Further, it was dried at 140 ° C. for 30 minutes. Then, it removed from the frame and heat-processed for 270 degreeC and 8 hours, and obtained the film sample (sample 108).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Comparative Example 9]
1-9. Film formation of PF-1 (Method of heating and leaving the dope after filtration through a metal net)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and PF-1 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor to dissolve PF-1, and then heated to 50 ° C., and a metal net having an average pore diameter of 15 μm was applied as a filter medium at a pressure of 0.5 MPa. PF-1 dope was obtained by pressure filtration. The filtration area at this time was 43 cm ² , and the time required for filtration was 3 hours. Thereafter, this PF-1 dope was allowed to stand at 50 ° C. for 2.5 hours, and then cast on a glass substrate using a small casting die having a width of 40 cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (sample 109).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Example 1]
2. Film production method (method of the present invention)
2-1. Film formation of PF-1 (Method of reducing the dope after filtration)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and PF-1 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor. After dissolving PF-1, it was heated to 50 ° C. and filtered with an average pore size of 40 μm (manufactured by Toyo Roshi Kaisha, Ltd., “# 63 ]) And pressure filtered at a pressure of 0.5 MPa to obtain a PF-1 dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. After that, the PF-1 dope was put in a glass bottle and placed in a vacuum apparatus (VELOS-301SD manufactured by EYELA) equipped with a vacuum pipe and kept under reduced pressure of 4000 to 5000 Pa for 5 minutes. did. Then, it cast on the glass substrate using the small casting die of width 40cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (Sample 201).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Example 2]
2-2. Film formation of PF-1 (Method of reducing pressure after ultrasonic treatment of the dope after filtration)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and PF-1 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor. After dissolving PF-1, it was heated to 50 ° C. and filtered with an average pore size of 40 μm (manufactured by Toyo Roshi Kaisha, Ltd., “# 63 ]) And pressure filtered at a pressure of 0.5 MPa to obtain a PF-1 dope. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. This PF-1 dope is agitated while being stirred, and then placed in a glass bottle and placed in a vacuum device (VOS-301SD manufactured by EYELA) equipped with a vacuum pipe, and allowed to stand under reduced pressure of 4000 to 5000 Pa for 5 minutes. As a result, the generation of bubbles was visually confirmed. Then, it cast on the glass substrate using the small casting die of width 40cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (Sample 202).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Example 3]
2-3. Film formation of PF-1 (Method of performing filtration using a filter aid)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and PF-1 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor to dissolve PF-1. Thereafter, 0.37 g of Dicalite 6000 (available from Mitsui Mining & Smelting Co., Ltd.) was added to the PF-1 solution as a filter aid, dispersed uniformly, heated to 50 ° C., and filter paper (Toyo filter paper (Toyo filter paper ( "# 63"), and pressure-filtered at a pressure of 0.5 MPa through a precoat layer formed by pre-filtering a mixed dispersion of 1000 g of dichloromethane and 3.2 g of Dicalite 6000. 1 dope was obtained. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. This PF-1 dope is agitated while being stirred, and then placed in a glass bottle and placed in a vacuum device (VOS-301SD manufactured by EYELA) equipped with a vacuum pipe, and allowed to stand under reduced pressure of 4000 to 5000 Pa for 5 minutes. As a result, the generation of bubbles was visually confirmed. Then, it cast on the glass substrate using the small casting die of width 40cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. The film was further dried at 140 ° C. for 30 minutes to obtain a film sample (Sample 203).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Example 4]
2-4. Film formation of PF-1 (method of performing two-step heat treatment)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and PF-1 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, it was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PF-1. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor to dissolve PF-1. Thereafter, 0.37 g of Dicalite 6000 (available from Mitsui Mining & Smelting Co., Ltd.) was added to the PF-1 solution as a filter aid, dispersed uniformly, heated to 50 ° C., and filter paper (Toyo filter paper (Toyo filter paper ( "# 63"), and pressure-filtered at a pressure of 0.5 MPa through a precoat layer formed by pre-filtering a mixed dispersion of 1000 g of dichloromethane and 3.2 g of Dicalite 6000. 1 dope was obtained. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. This PF-1 dope is agitated while being stirred, and then placed in a glass bottle and placed in a vacuum device (VOS-301SD manufactured by EYELA) equipped with a vacuum pipe, and allowed to stand under reduced pressure of 4000 to 5000 Pa for 5 minutes. As a result, the generation of bubbles was visually confirmed. Then, it cast on the glass substrate using the small casting die of width 40cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. Further, it was dried at 140 ° C. for 30 minutes. Next, with the frame attached, heat treatment was performed at 270 ° C. for 8 hours after removing the frame at 270 ° C. for 8 hours to obtain a film sample (sample 204).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-1 (weight average molecular weight 65000, glass transition temperature 320 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Example 5]
2-5. Film formation of PF-7 (same method as 2-4)
In a 1 L glass bottle having a stirring blade, a solvent having the following composition was prepared, and PF-7 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, the mixture was left at room temperature (25 ° C.) for 1 hour to swell PF-7. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor to dissolve PF-7. Thereafter, 0.37 g of Dicalite 6000 (available from Mitsui Mining & Smelting Co., Ltd.) was added to the PF-7 solution as a filter aid, dispersed uniformly, heated to 50 ° C., and filter paper having an average pore size of 40 μm (Toyo Filter Paper ( "# 63"), and pressure-filtered at a pressure of 0.5 MPa through a precoat layer formed by pre-filtering a mixed dispersion of 1000 g of dichloromethane and 3.2 g of Dicalite 6000. 7 dope was obtained. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. This PF-7 dope is agitated while being stirred, and then placed in a glass bottle, placed in a vacuum apparatus (VOS-301SD manufactured by EYELA) equipped with a vacuum pipe, and allowed to stand under reduced pressure of 4000 to 5000 Pa for 5 minutes. As a result, the generation of bubbles was visually confirmed. Then, it cast on the glass substrate using the small casting die of width 40cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. Further, it was dried at 140 ° C. for 30 minutes. Next, the film was removed from the frame for 8 hours with the frame attached, and heat treatment was performed at 300 ° C. for 8 hours to obtain a film sample (sample 205).
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PF-7 (weight average molecular weight 60000, glass transition temperature 350 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

[Example 6]
2-6. Film formation of PS-4 (same method as 2-4)
A solvent having the following composition was prepared in a 1 L glass bottle having a stirring blade, and PS-4 powder (average size 1 mm) was gradually added while stirring well, so that the whole was 920 g. After the addition, the mixture was allowed to stand at room temperature (25 ° C.) for 1 hour to swell PS-4. Next, the glass bottle was sealed, and stirring was continued for 24 hours with a seesaw rotary rotor to dissolve PS-4. Thereafter, 0.37 g of Dicalite 6000 (Mitsui Metal Mining Co., Ltd.) as a filter aid was added to the PS-4 solution and dispersed uniformly, heated to 50 ° C., and filter paper (Toyo filter paper (Toyo filter paper ( "# 63"), and pressure-filtered at a pressure of 0.5 MPa through a precoat layer formed by pre-filtering a mixed dispersion of 1000 g of dichloromethane and 3.2 g of Dicalite 6000. 4 dopes were obtained. The filtration area at this time was 43 cm ² , and the time required for filtration was 1 hour. The PS-4 dope is agitated while being stirred, and then placed in a glass bottle, placed in a vacuum apparatus (VOS-301SD manufactured by EYELA) equipped with a vacuum pipe, and allowed to stand under reduced pressure of 4000 to 5000 Pa for 5 minutes. As a result, the generation of bubbles was visually confirmed. Then, it cast on the glass substrate using the small casting die of width 40cm. After casting, the film was dried at 22 ° C. for 2 minutes and at 70 ° C. for 3 minutes under blowing at a dew point of 6 ° C., then the film was peeled off from the glass substrate, and a metal frame with an inner diameter of 32 cm × 100 cm was framed. Further, it was dried at 140 ° C. for 30 minutes. Next, the film sample (sample 206) was obtained by carrying out heat treatment at 200 ° C. for 8 hours after removing the frame with the frame attached, at 200 ° C. for 8 hours.
The film thickness, total light transmittance, glass transition temperature, number of bubbles, number of foreign matters, dimensional change rate, and flatness of the obtained film sample are shown in Table 1 together with the filtration time.

〔composition〕
-21 parts by mass of the above exemplified compound PS-4 (weight average molecular weight 63000, glass transition temperature 260 ° C. by DSC measurement)
・ 79 parts by mass of dichloromethane

  In Table 1, it can be seen from the results of Comparative Examples 1 to 3 that a film using cellulose triacetate can be obtained as a good film having a small number of bubbles regardless of which degassing method is used. On the other hand, Comparative Examples 6 to 9 using a high Tg polymer that can be used in the present invention have a bubble number as compared with Comparative Example 4 in which degassing is not performed even if a degassing method effective with cellulose triacetate is used. Little reduction effect was seen. On the other hand, Comparative Example 5 shows some effect of reducing the number of bubbles by performing drying at low temperature for a long time. However, since this method requires a long time for drying, it is insufficient from the viewpoint of compatibility with production speed. .

On the other hand, Example 1 using the vacuum degassing of the present invention has a significant effect of reducing the number of bubbles without using low temperature and long time drying. Furthermore, in the samples 202 to 206 (Examples 2 to 6) of the present invention in which ultrasonic treatment was performed before degassing under reduced pressure, the generation was improved so that almost no bubbles were observed. Further, the samples 203 to 206 (Examples 3 to 6) of the present invention that were filtered using a filter aid did not require a long filtration time, and the number of foreign matters was hardly recognized. Moreover, it turns out that the sample 204-206 (Examples 4-6) of this invention which performed the heat processing of 2 steps | paragraphs can improve a dimensional change rate, without deteriorating planarity.
From the above, it can be seen that the present invention makes it possible to produce a film having excellent heat resistance, transparency, flatness, and dimensional stability, and having less foreign matter and bubbles mixed in with high productivity.

Claims (9)

A method for producing a film in which a dope obtained by dissolving a polymer in an organic solvent is cast on a support and dried to form a film having a glass transition temperature of 250 ° C. or higher and a total light transmittance of 70% or higher.
A method for producing a film, wherein the prepared dope is degassed under reduced pressure before casting.   The method for producing a film according to claim 1, wherein ultrasonic treatment is performed on the dope before casting.   The method for producing a film according to claim 1 or 2, wherein the dope before casting is filtered using a filter aid.   The method for producing a film according to any one of claims 1 to 3, wherein the dried film is subjected to two-stage heat treatment. The polymer has a repeating unit including a spiro structure represented by the following general formula (1) or a cardo structure represented by the following general formula (2). The manufacturing method of the film of description.

[In general formula (1), ring α represents a monocyclic or polycyclic ring, and the two rings are connected by a spiro bond. ]

[In general formula (2), ring β and ring γ represent a monocyclic or polycyclic ring, and the two rings γ may be the same or different. Ring β and ring γ are connected by one quaternary carbon atom on ring β. ]   The film manufactured by the manufacturing method of the film as described in any one of Claims 1-5. The film according to claim 6, wherein the number of bubbles per 1 m ² is 10 or less. The film according to claim 6 or 7, wherein the number of foreign matters of 5 µm or more per 70 mm ² is 60 or less.   9. The film according to claim 6, wherein a dimensional change rate when held at 200 ° C. for 5 hours is ± 0.1% or less.