JP2009167235A - Process for production of polyimide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which enables high-speed film formation by casting a solution of a polyimide precursor dissolved in a solvent onto a substrate to improve productivity, and further to enhance productivity of a thinner film formation. <P>SOLUTION: A process for production of a polyimide film includes casting a solution of a polyimide precursor dissolved in a solvent onto a substrate; removing the solvent contained in the solution to peel off a self-supporting film from the substrate; and heating the self-supporting film for imidation, which is characterized by performing cast with a solvent interposed between the substrate and the solution of polyimide precursor to be cast, the solvent having compatibility with the polyimide precursor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a polyimide film using a solvent solution of a polyimide precursor such as polyamic acid.

The polyimide film is used as an insulating member for electric wiring. Conventionally, a polyimide film is manufactured from a polyimide precursor solution or a polyimide solution.
In Patent Document 1, in a method for producing a polyimide film by a casting method, a polymer solution containing polyamic acid or polyimide is cast into a film form on a metal substrate surface which has been previously applied with a solvent and heat-treated at 60 to 250 ° C. A method for producing a polyimide film is disclosed.
Patent Document 2 discloses that in a method of obtaining a film or sheet-like molded body by casting an organic polymer solution on a support, the organic polymer solution is interposed between the support and the cast organic polymer solution film. A film forming method characterized by casting with a solvent having compatibility with a molecular body is disclosed.
JP-A-60-244508 JP-A-11-170281

The polyimide film is obtained by casting a solvent solution of a polyimide precursor on a support, removing the solvent in the solution and peeling it from the support as a self-supporting film, and heating the self-supporting film to imidize it. It is manufactured. However, in order to peel the self-supporting film from the support, the peel strength between the self-supporting film and the support is low, and the tensile strength of the self-supporting film itself is required. It is also possible to change the drying conditions after casting to increase the strength of the self-supporting film, but it becomes difficult to remove the solvent remaining in the resulting film, and the characteristics of the support side surface and the gas side surface are different. Or because the physical properties of the film itself may be reduced. Therefore, it is difficult to increase the production speed with a manufacturing method that satisfies these conditions, and a manufacturing method that improves the productivity without greatly changing the physical properties of the obtained film is required. In particular, when producing a thin film, there is a demand for a production method in which the strength of the self-supporting film is difficult to obtain and the productivity is improved.
In the present invention, a solvent solution of a polyimide precursor is cast on a support to provide a production method capable of high-speed film formation for the purpose of improving productivity, and further to improve the productivity of a thin film. Objective.
Furthermore, in the present invention, in the method for producing a polyimide film, the solvent solution of the polyimide precursor is cast on a support, and the solvent in the solution is removed until the self-supporting film is peeled off from the support. Polyimides that improve the strength of self-supporting films, improve releasability, or improve the castability of a polyimide precursor solvent solution onto a support to improve productivity, especially for thin films. It aims at providing the manufacturing method of a film.

  In particular, when polymerizing a polyamic acid obtained from an acid component containing a 3,3 ′, 4,4′-biphenyltetracarboxylic acid component and a diamine component containing p-phenylenediamine, the viscosity is high when the polymer concentration is high, Further, since the solution is easily gelled, it is difficult to manufacture at a high concentration, and there is a limit to improvement in productivity. Therefore, productivity using a solvent solution of polyamic acid obtained from an acid component containing a 3,3 ′, 4,4′-biphenyltetracarboxylic acid component and a diamine component containing p-phenylenediamine, particularly a thin film It aims at providing the manufacturing method which improves productivity.

In the first aspect of the present invention, a solvent solution of a polyimide precursor is cast on a support, the solvent in the solution is removed, the film is peeled from the support as a self-supporting film, and the self-supporting film is heated to form an imide. Is a method for producing a polyimide film,
A method for producing a polyimide film, comprising casting a solvent having compatibility with a polyimide precursor between a support and a solvent solution of a polyimide precursor to be cast.
According to the second aspect of the present invention, a solvent solution of a polyimide precursor is cast on a support, the solvent in the solution is removed, the self-supporting film is peeled off from the support, and the self-supporting film is heated to form an imide. Is a method for producing a polyimide film,
Cast with a solvent having compatibility with the polyimide precursor between the support and the solvent solution of the polyimide precursor to be cast,
The solvent interposed between the support and the solvent solution of the polyimide precursor to be cast contains at least one additive component selected from an imidization catalyst, a dehydration condensation agent, a release agent, and a surfactant. It is a manufacturing method of a polyimide film.
When casting the solvent solution of the polyimide precursor to the support by interposing a solvent having compatibility with the polyimide precursor between the support and the solvent solution of the polyimide precursor to be cast, The stability of landing of the casting solution on the support is improved, the productivity of a thin film is improved, and a uniform film can be easily produced even if the production speed is increased.
In the case of performing the casting by interposing a solvent having compatibility with the polyimide precursor between the support and the solvent solution of the polyimide precursor to be cast,
1) When the solvent contains an imidizing agent, it is possible to improve the strength of the self-supporting film at the time of peeling from the support, and there are effects such as suppression of film breakage and generation of cracks. It is considered that the imidization on the support surface side of the solvent solution of the polyimide precursor cast on the support can be promoted,
It is preferable to use for the manufacturing method which has the process of apply | coating a solvent especially to the single side | surface or both surfaces of the self-supporting film peeled from the support body.
2) When the solvent contains a release agent, the releasability is improved, and when the release agent is internally added to the solvent solution of the polyimide precursor, the release agent is unnecessary or the addition of the release agent. The amount can be reduced. The release agent added internally to the solvent solution of the polyimide precursor may bleed out or may be colored during high-temperature treatment, and it is effective to reduce the amount of release agent added to the solvent solution of the polyimide precursor. Think of it as a means.
3) When the solvent contains a surfactant, when the solvent solution of the polyimide precursor is cast on a support, it has an effect of suppressing repelling of the cast solution and the support.
In addition, combinations of two or more from the above 1), 2) and 3) (examples of combinations include an imidizing agent and a release agent, an imidizing agent and a surfactant, a release agent and a surfactant, or an imidizing agent) The combination of the release agent and the surfactant) is preferable because the combined effect is obtained, and the case where the solvent contains at least an imidizing agent and a release agent is particularly preferable.

Preferred embodiments of the method for producing the first or second polyimide film of the present invention are shown below, and a plurality of these embodiments can be arbitrarily combined.
1) It is preferable for the physical property of the self-supporting film after a heating that the solvent intervening between the support body and the solvent solution of the polyimide precursor to be cast is 5 to 100 g / m ² .
2) The solvent intervening between the support and the solvent solution of the polyimide precursor to be cast is 10 to 80 parts by mass of the imidation catalyst, 10 to 80 parts by mass of the dehydration condensing agent, and 100 parts by mass with respect to 100 parts by mass of the solvent. It is preferable for the physical properties of the self-supporting film after heating to include an additive component selected from 10 to 80 parts by mass of the agent and 10 to 80 parts by mass of the surfactant.
3) The polyimide precursor is a polyimide precursor obtained from an acid component containing a 3,3 ′, 4,4′-biphenyltetracarboxylic acid component and a diamine component containing p-phenylenediamine.
4) The solvent interposed between the support and the solvent solution of the polyimide precursor to be cast has compatibility with the solvent of the polyimide precursor.
5) The solvent solution of a polyimide precursor contains 5 mass%-50 mass% of a polyimide precursor in the solvent solution of a polyimide precursor.
6) The solvent solution of the polyimide precursor has a solution viscosity in the range of 500 to 5000 poise.
7) The thickness of the polyimide film is in the range of 5 to 15 μm.

In the first method for producing a polyimide film of the present invention, casting is performed by interposing a solvent having compatibility with the polyimide precursor between the support and the solvent solution of the polyimide precursor to be cast. Film formation becomes possible and productivity can be improved.
In the production method of the second polyimide film of the present invention, the solvent solution of the polyimide precursor is cast on the support, and the solvent in the solution is removed until the self-supporting film is peeled off from the support. Improves the strength of the self-supporting film to be peeled, improves the peelability, or improves the castability of the solvent solution of the polyimide precursor onto the support, which stabilizes productivity and enables high-speed film formation. The manufacturing method of the polyimide film which improves can be provided.

  Examples of the polyimide precursor include polyamic acid, polyamic acid salt, polyamic acid alkyl ester, polyamic acid trimethylsilyl ester, mixed solution of tetracarboxylic acid diester and diamine, and further include those containing two or more of these. I can do it. In particular, the polyimide precursor is preferably a polyamic acid (including a partly imidized amic acid) synthesized from a component containing tetracarboxylic dianhydride and diamine.

  As an example of a method for producing a polyimide precursor, tetracarboxylic acid components such as aromatic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic diamine, aliphatic It can be obtained by reacting diamine components such as diamine and alicyclic diamine in a gas phase or in a solvent.

（但し、一般式（１）において、Ｙは一般式（２）で示す群から選択された２価の基を示す。）

（但し、一般式（２）において、Ｒ_２、Ｒ_３、Ｒ_４及びＲ_５は、単結合、−Ｏ−，−Ｓ−，−ＣＯ−，−ＳＯ_２−，−ＣＨ_２−，−Ｃ（ＣＨ_３）_２−及び−Ｃ（ＣＦ_３）_２−から選ばれる２価の基を示し、
Ｍ_１〜Ｍ_４、Ｍ’_１〜Ｍ’_４、Ｌ_１〜Ｌ_４、Ｌ’_１〜Ｌ’_４及びＬ”_１〜Ｌ”_４は、−Ｈ，−Ｆ，−Ｃｌ，−Ｂｒ，−Ｉ，−ＣＮ，−ＯＣＨ_３，−ＯＨ，−ＣＯＯＨ，−ＣＨ_３，−Ｃ_２Ｈ_５または−ＣＦ_３を示す。
Ｒ_２、Ｒ_３、Ｒ_４及びＲ_５は、それぞれ独立して、同一であっても、異なっていてもよく、
Ｍ_１〜Ｍ_４、Ｍ’_１〜Ｍ’_４、Ｌ_１〜Ｌ_４、Ｌ’_１〜Ｌ’_４及びＬ”_１〜Ｌ”_４は、それぞれ独立して、同一であっても、異なっていてもよい。）
中でも、好ましいジアミンとしては、下記一般式（１’）で表されるものが挙げられ、さらに好ましいジアミンとしては、下記一般式（１”）で表されるものが挙げられる。

（但し、一般式（１’）において、Ｙは一般式（２’）で示す群から選択された２価の基を示す。）

（但し、一般式（２’）において、Ｒ_２は、単結合、−Ｏ−、−Ｓ−、−ＣＨ_２−及び−Ｃ（ＣＨ_３）_２−から選ばれる２価の基を示し、
Ｒ_３及びＲ_４は、−Ｏ−または−Ｓ−を示し、
Ｒ_５は、単結合、−Ｏ−、−ＣＨ_２−及び−Ｃ（ＣＨ_３）_２−から選ばれる２価の基を示し、
Ｍ_１〜Ｍ_４、Ｍ’_１〜Ｍ’_４、Ｌ_１〜Ｌ_４、Ｌ’_１〜Ｌ’_４及びＬ”_１〜Ｌ”_４は、−Ｈまたは−ＣＨ_３を示す。
Ｒ_２、Ｒ_３、Ｒ_４及びＲ_５は、それぞれ独立して、同一であっても、異なっていてもよく、
Ｍ_１〜Ｍ_４、Ｍ’_１〜Ｍ’_４、Ｌ_１〜Ｌ_４、Ｌ’_１〜Ｌ’_４及びＬ”_１〜Ｌ”_４は、それぞれ独立して、同一であっても、異なっていてもよい。）

（但し、一般式（１”）において、Ｙは一般式（２”）で示す群から選択された２価の基を示す。）

（但し、一般式（２”）において、Ｒ_２は、単結合、−Ｏ−、−Ｓ−、−ＣＨ_２−及び−Ｃ（ＣＨ_３）_２−から選ばれる２価の基を示し、
Ｍ_１〜Ｍ_４及びＭ’_１〜Ｍ’_４は、−Ｈ、−ＯＣＨ_３、−ＣＨ_３または−Ｃｌを示す。
Ｒ_２は、それぞれ独立して、同一であっても、異なっていてもよく、
Ｍ_１〜Ｍ_４及びＭ’_１〜Ｍ’_４は、それぞれ独立して、同一であっても、異なっていてもよい。） As the diamine that is a raw material of the polyimide precursor, diamines such as known aromatic diamines, aliphatic diamines, and alicyclic diamines can be used, and examples thereof include aromatic diamines represented by the following general formula (1). It is done.

(However, in General Formula (1), Y represents a divalent group selected from the group represented by General Formula (2).)

(However, in the general formula _{(2), R 2, R} 3, R 4 and _{R 5} is a single bond, -O -, - S -, - CO -, - SO 2 -, - CH 2 -, - C A divalent group selected from (CH ₃ ) ₂ — and —C (CF ₃ ) ₂ —;
M _{1 to} M ₄ , M ′ _{1 to} M ′ ₄ , L _{1 to} L ₄ , L ′ _{1 to} L ′ ₄ and L ″ _{1 to} L ″ ₄ are represented by —H, —F, —Cl, —Br, — shows _{I, -CN, -OCH 3, -OH} , -COOH, a -CH 3, _-C 2 _{H 5} or -CF _3.
R ₂ , R ₃ , R ₄ and R ₅ may each independently be the same or different,
M _{1 to} M ₄ , M ′ _{1 to} M ′ ₄ , L _{1 to} L ₄ , L ′ _{1 to} L ′ ₄ and L ″ _{1 to} L ″ ₄ are each independently the same or different. May be. )
Among them, preferred diamines include those represented by the following general formula (1 ′), and more preferred diamines include those represented by the following general formula (1 ″).

(However, in General Formula (1 ′), Y represents a divalent group selected from the group represented by General Formula (2 ′).)

(However, in General Formula (2 ′), R ₂ represents a divalent group selected from a single bond, —O—, —S—, —CH ₂ —, and —C (CH ₃ ) ₂ —;
R ₃ and R ₄ represent —O— or —S—,
R ₅ represents a divalent group selected from a single bond, —O—, —CH ₂ —, and —C (CH ₃ ) ₂ —,
M _{1 to} M ₄ , M ′ _{1 to} M ′ ₄ , L _{1 to} L ₄ , L ′ _{1 to} L ′ ₄ and L ″ _{1 to} L ″ ₄ represent —H or —CH ₃ .
R ₂ , R ₃ , R ₄ and R ₅ may each independently be the same or different,
M _{1 to} M ₄ , M ′ _{1 to} M ′ ₄ , L _{1 to} L ₄ , L ′ _{1 to} L ′ ₄ and L ″ _{1 to} L ″ ₄ are each independently the same or different. May be. )

(In the general formula (1 ″), Y represents a divalent group selected from the group represented by the general formula (2 ″).)

(In the general formula (2 ″), R ₂ represents a divalent group selected from a single bond, —O—, —S—, —CH ₂ —, and —C (CH ₃ ) ₂ —;
M _{1 to} M ₄ and M ′ _{1 to} M ′ ₄ represent —H, —OCH ₃ , —CH ₃ or —Cl.
R ₂ may be independently the same or different,
M _{1 to} M ₄ and M ′ _{1 to} M ′ ₄ may be independently the same or different. )

As a specific example of diamine,
1) One diamine nucleus diamine such as 1,4-diaminobenzene, 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene,
2) 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4, 4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4 , 4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4,4′-diaminobenzanilide, 3,3 ′ -Dichlorobenzidine, 3,3'-dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfide 3,3′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 3,3′-diamino-4,4′-dichlorobenzophenone 3,3′-diamino-4,4′-dimethoxybenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 2,2-bis (3-aminophenyl) ) Propane, 2,2-bis (4-aminophenyl) propane, , 2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-aminophenyl) -1,1,1,3,3,3 Two diamine diamines such as hexafluoropropane, 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfoxide, 4,4′-diaminodiphenyl sulfoxide,
3) 1,3-bis (3-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (3-aminophenyl) benzene, 1,4-bis (4-amino) Phenyl) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (3 -Aminophenoxy) -4-trifluoromethylbenzene, 3,3'-diamino-4- (4-phenyl) phenoxybenzophenone, 3,3'-diamino-4,4'-di (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenyl sulfide) benzene, 1,3-bis (4-aminophenyl sulfide) benzene, 1,4-bis (4-aminophenyls) Fido) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-aminophenylsulfone) benzene, 1,4-bis (4-aminophenylsulfone) benzene, 1,3- Bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 1,4-bis [2- (4-aminophenyl) isopropyl] benzene, etc. The benzene core of three diamines,
4) 3,3′-bis (3-aminophenoxy) biphenyl, 3,3′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [3- (3-aminophenoxy) phenyl] ether, bis [3- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, Bis [4- (4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, bis [3- (4-aminophenoxy) phenyl] ketone, bis [4- (3-amino Phenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [3- (3-aminophenoxy) phenyl] Sulfide, bis [3- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [3- (3 -Aminophenoxy) phenyl] sulfone, bis [3- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, Bis [3- (3-aminophenoxy) phenyl] methane, bis [3- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-amino Phenoxy) phenyl] methane, 2,2-bis [3- (3-aminophenoxy) phenyl] propane, , 2-bis [3- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl ] Propane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [3- (4-aminophenoxy) Phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoro Four diamine diamines such as propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane,
5-amino-2- (p-aminophenyl) benzoxazole, 5-amino-2- (m-aminophenyl) benzoxazole, 6-amino-2- (p-aminophenyl) benzoxazole, 6-amino-2 -(M-aminophenyl) benzoxazole, 2,2'-p-phenylenebis (5-aminobenzoxazole), 2,2'-p-phenylenebis (6-aminobenzoxazole), 1- (5-amino Benzoxazolo) -4- (6-aminobenzoxazolo) benzene, 2,6- (4,4′-diaminodiphenyl) benzo [1,2-d: 5,4-d ′] bisoxazole, 2, 6- (4,4′-diaminodiphenyl) benzo [1,2-d: 4,5-d ′] bisoxazole, 2,6- (3,4′-diaminodiphenyl) benzo [1,2- d: 5,4-d ′] bisoxazole, 2,6- (3,4′-diaminodiphenyl) benzo [1,2-d: 4,5-d ′] bisoxazole, 2,6- (3 3'-diaminodiphenyl) benzo [1,2-d: 5,4-d '] bisoxazole, 2,6- (3,3'-diaminodiphenyl) benzo [1,2-d: 4,5-d '] Aromatic diamines having a benzoxazole structure such as bisoxazole can be mentioned. These may be used alone or in combination of two or more. The diamine to be used can be appropriately selected according to desired characteristics.

（但し、一般式（３）において、Ｘは一般式（４）で示す群から選択された４価の基を示す。）

（但し、一般式（４）において、Ｒ_１は、一般式（５）から選ばれる２価の基を示す。）

中でも、好ましいテトラカルボン酸二無水物としては、下記一般式（３’）で表されるものが挙げられる。

（但し、一般式（３’）において、Ｘは一般式（４’）で示す群から選択された４価の基を示す。）

Examples of the tetracarboxylic acid component that is a raw material for the polyimide precursor include tetracarboxylic dianhydrides such as known aromatic tetracarboxylic dianhydrides, aliphatic tetracarboxylic dianhydrides, and alicyclic tetracarboxylic dianhydrides. For example, aromatic tetracarboxylic dianhydrides represented by the following general formula (3), or esters thereof.

(In the general formula (3), X represents a tetravalent group selected from the group represented by the general formula (4).)

(However, in General Formula (4), R ₁ represents a divalent group selected from General Formula (5).)

Among these, preferred tetracarboxylic dianhydrides include those represented by the following general formula (3 ′).

(However, in General Formula (3 ′), X represents a tetravalent group selected from the group represented by General Formula (4 ′).)

In the method for producing a polyimide film, the polyimide film comprises an aromatic tetracarboxylic dianhydride, an aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, or a tetracarboxylic acid component such as an ester thereof, It can be obtained by synthesizing a polyimide precursor by reacting a diamine component such as aromatic diamine, aliphatic diamine, or alicyclic diamine in a gas phase or in a solvent, and further imidizing by heating the polyimide precursor. .
In the method for producing a polyimide film, the polyimide film produces an aromatic polyimide film obtained from a tetracarboxylic acid component having an aromatic tetracarboxylic dianhydride as a main component and a diamine having an aromatic diamine as a main component. be able to.
As the tetracarboxylic acid component, an aromatic tetracarboxylic dianhydride represented by the general formula (3), preferably an aromatic tetracarboxylic dianhydride represented by the general formula (3 ′) is used as a main component. A known tetracarboxylic dianhydride other than the aromatic tetracarboxylic dianhydride can be used as long as the characteristics are not impaired.
As the tetracarboxylic dianhydride, the aromatic tetracarboxylic dianhydride represented by the general formula (3) is 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol. It is preferable to use those containing at least%.
As the diamine component, an aromatic diamine represented by the general formula (1), preferably an aromatic diamine represented by the general formula (1 ′), more preferably an aromatic diamine represented by the general formula (1 ″) is used as a main component. Known diamines other than the aromatic diamine can be used as long as the characteristics of the present invention are not impaired.
As the diamine, the diamine represented by the general formula (1), preferably the diamine represented by the general formula (1 ′), more preferably the diamine represented by the general formula (1 ″) is 50 mol% or more, more preferably 70 mol% or more, More preferably, it contains 80 mol% or more, particularly preferably 90 mol% or more.

  Specific examples of tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), 2,2 ′, 3,3 ′. -Biphenyltetracarboxylic dianhydride, 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride oxydiphthalic dianhydride, diphenylsulfone-3,4,3', 4'-tetracarboxylic dianhydride Bis (3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride object 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, p-phenylenebis (trimellitic acid monoester acid anhydride), p-methylphenylenebis (trimellitic acid monoester acid anhydride), p- (2,3-dimethylphenylene) bis (trimellitic acid monoester acid anhydride), 4,4′-biphenylenebis (trimellitic acid monoester acid anhydride), 1,4-naphthalenebis (trimellitic acid) Monoester anhydride), 2,6-naphthalenebis (trimellitic acid monoester anhydride) 2,2-bis (4-hydroxyphenyl) propanedibenzoate-3,3 ′, 4,4′-tetracarboxylic Acid dianhydride, m-terphenyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, p-terphenyl-3,4,3 ′, 4′-tetra Rubonic acid dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis ( 3,4-dicarboxyphenoxy) biphenyl dianhydride, 2,2-bis [(3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4 ′-(2,2-hexafluoroisopropylidene) diphthalic dianhydride, and the like. It is also preferable to use an aromatic tetracarboxylic acid such as 2,3,3 ', 4'-diphenylsulfonetetracarboxylic acid. These may be used alone or in combination of two or more. The tetracarboxylic dianhydride to be used can be appropriately selected according to desired characteristics.

The polyimide precursor is 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,3, Esters such as biphenyltetracarboxylic dianhydride such as 3 ′, 4′-biphenyltetracarboxylic dianhydride oxydiphthalic dianhydride, pyromellitic anhydride and p-phenylenebis (trimellitic acid monoester anhydride) A polyimide precursor such as polyamic acid obtained by polymerizing an acidic component containing a component selected from an acid dianhydride having a structure and a diamine component;
Further, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4 Acids having ester structures such as biphenyltetracarboxylic dianhydride such as' -biphenyltetracarboxylic dianhydride oxydiphthalic dianhydride, pyromellitic anhydride and p-phenylenebis (trimellitic acid monoester anhydride) A polyamic obtained by polymerizing an acidic component containing a component selected from dianhydrides and a diamine component containing a component selected from p-phenylenediamine, 4,4′-diaminodiphenyl ether and an aromatic diamine having a benzoxazole structure Polyimide precursors such as acids,
In particular, out of a total molar amount of 200 mol% obtained by adding 100 mol% of the acid component and 100 mol% of the diamine component, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), 2, Biphenyltetracarboxylic dianhydride such as 2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride oxydiphthalic dianhydride, anhydrous pyro An acidic component containing a component selected from methanic acid and an acid dianhydride having an ester structure such as p-phenylenebis (trimellitic acid monoester acid anhydride), p-phenylenediamine, 4,4′-diaminodiphenyl ether, and The total molar amount of the diamine component including the component selected from the aromatic diamine having a benzoxazole structure is preferably 100 mol% or more, more preferably Preferably, a polyimide precursor such as polyamic acid obtained by polymerization using 140 mol% or more, more preferably 170 mol% or more, particularly preferably 180 mol% or more can be preferably used.

The polyimide precursor can be synthesized by a known method. Random polymerization, block polymerization, or a plurality of polyimide precursor solutions or polyimide solutions are synthesized in advance and mixed under reaction conditions after mixing the plurality of solutions. To achieve a uniform solution.
The degree of polymerization of a polyimide precursor such as polyamic acid can be such that the polyimide precursor can be dissolved in an organic solvent, cast, a self-supporting film can be produced, and heated to imidize to produce a film. That's fine.

  The solvent solution of the polyimide precursor comprises a tetracarboxylic acid component and a diamine component in an organic solvent at a temperature of about 100 ° C. or lower, further 80 ° C. or lower, further 0 to 60 ° C., particularly 20 to 60 ° C. By reacting for about 0.2 to 100 hours, a solvent solution of a polyimide precursor such as a polyamic acid solvent solution can be produced, and this polyamic acid solvent solution can be used as a dope solution (cast solution).

  In carrying out the polymerization reaction of the polyimide precursor solvent solution such as a polyamic acid solvent solution, the concentration of all monomers in the organic polar solvent may be appropriately selected according to the purpose of use and the purpose of production. It is preferable that the density | concentration of all the inside monomers becomes like this. Preferably it is 5-50 mass%, More preferably, it is 10-30 mass%, More preferably, it is 13-25 mass%, Most preferably, it is 16-22 mass%.

  When carrying out the polymerization reaction of a polyimide precursor solvent solution such as a polyamic acid solvent solution, the solution viscosity can be cast by dissolving the polyimide precursor in an organic solvent, and a self-supporting film can be produced. The solvent solution of the polyimide precursor such as a polyamic acid solvent solution has a rotational viscosity measured at 30 ° C. of preferably 500 to 5000 poise, more preferably 1000 to 4000 poise, and still more preferably. Is preferably from 1500 to 3000 poise, particularly preferably from 1600 to 2500 poise from the viewpoint of workability in handling a solvent solution of a polyimide precursor such as this polyamic acid solvent solution. Therefore, it is desirable to carry out the polymerization reaction to such an extent that the solvent solution of the polyimide precursor such as the polyamic acid solvent solution to be produced exhibits the above viscosity.

In the present invention,
The polyimide precursor has a solution viscosity obtained from an acid component containing a 3,3 ′, 4,4′-biphenyltetracarboxylic acid component and a diamine component containing p-phenylenediamine in the range of 500 to 5000 poise, polymer concentration Using 5 mass% to 50 mass% polyimide precursor,
A method for producing a polyimide film in which a solvent solution of a polyimide precursor is cast on a support, the solvent in the solution is removed, the film is peeled from the support as a self-supporting film, and the self-supporting film is heated to imidize And
A polyimide characterized by casting a solvent having compatibility with the polyimide precursor in an amount in the range of 5 to 100 g / m ² between the support and the solvent solution of the polyimide precursor to be cast. It is a manufacturing method of a film.

In the present invention,
The polyimide precursor has a solution viscosity obtained from an acid component containing a 3,3 ′, 4,4′-biphenyltetracarboxylic acid component and a diamine component containing p-phenylenediamine in the range of 500 to 5000 poise, polymer concentration Using 5 mass% to 50 mass% polyimide precursor,
A method for producing a polyimide film in which a solvent solution of a polyimide precursor is cast on a support, the solvent in the solution is removed, the film is peeled from the support as a self-supporting film, and the self-supporting film is heated to imidize And
Cast a solvent having compatibility with the polyimide precursor between the support and the solvent solution of the polyimide precursor to be cast with an amount in the range of 5 to 100 g / m ² interposed therebetween,
The solvent intervening between the support and the solvent solution of the polyimide precursor to be cast is 10 to 80 parts by mass of the imidization catalyst, 10 to 80 parts by mass of the dehydrating condensing agent, and 10 parts by mass of the release agent. It is a manufacturing method of the polyimide film characterized by including the additional component chosen from -80 mass parts and surfactant 10-80 mass parts, and a compounding quantity.

Polyimide precursors such as polyamic acid are approximately equimolar amounts of diamine component and tetracarboxylic acid component, a little excess amount of diamine component or a little excess amount of acid component in a solvent to react with polyimide such as polyamic acid It is possible to obtain a solvent solution of the precursor (a part thereof may be imidized as long as a uniform solution state is maintained).
Polyimide precursors such as polyamic acids are used to diamine anhydrides, such as phthalic anhydride and its substitution, hexahydrophthalic anhydride and its substitution, succinic anhydride and its substitution, etc. In particular, it can be synthesized by adding phthalic anhydride.
Polyimide precursors such as polyamic acids are used in organic solvents where the amount of diamine (as the number of moles of amino group) is the total number of moles of acid anhydrides (as acid anhydride groups of tetraacid dianhydride and dicarboxylic acid anhydride). As a total mole) of 0.95 to 1.05, particularly 0.98 to 1.02, and particularly preferably 0.99 to 1.01. When the dicarboxylic acid anhydride is used, each component can be reacted at a ratio of 0.05 or less as a ratio of the tetracarboxylic dianhydride to the molar amount of the acid anhydride group.

In the case of performing the casting by interposing a solvent having compatibility with the polyimide precursor between the support and the solvent solution of the polyimide precursor to be cast,
Any solvent can be used as long as it is compatible with the polyimide precursor, but the polyimide precursor is preferably 1 part by mass or more, more preferably 100 parts by mass of the solvent at 25 ° C. Is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and particularly preferably 5 parts by mass or more.
Further, the solvent preferably has compatibility with the solvent used for the solvent solution of the polyimide precursor, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, more preferably 100 parts by mass of the solvent at 25 ° C. It is preferable to use 30 parts by mass or more, particularly preferably 50 parts by mass or more that does not undergo phase separation even when mixed.
In particular, as a solvent, it is preferable in terms of operation or production to use a solvent containing a polyimide precursor solvent used for casting, or the same solvent as a polyimide precursor solvent used for casting.

  Solvents used for the production or casting of polyimide precursors such as polyamic acid are N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, dimethyl sulfoxide, hexamethyl Examples thereof include organic solvents such as phosphoramide, N-methylcaprolactam, and cresols. These organic solvents may be used alone or in combination of two or more.

Solvents include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, N-methylcaprolactam, cresols, etc. Can be mentioned. These organic solvents may be used alone or in combination of two or more.
It is preferable to use a solvent that contains the same organic solvent as the organic solvent used for producing or casting the polyimide precursor such as polyamic acid, and further using the same organic solvent as the organic solvent used for producing the polyimide precursor such as polyamic acid. In 100% by mass of the solvent, 30 to 100% by mass, more preferably 50 to 100% by mass, and particularly preferably 80 to 100% by mass.

  The solvent solution of the polyimide precursor can contain at least one additive component selected from a phosphorus stabilizer, an imidizing agent and a release agent contained in the solvent.

  For the purpose of limiting the gelation of polyimide precursors such as polyamic acid, phosphorus stabilizers can be added. For example, triphenyl phosphite, triphenyl phosphate, etc. It can add in 0.01-1 mass% with respect to 100 mass%.

As the solvent solution of the polyimide precursor or the solvent, a solvent containing an imidizing agent selected mainly from an imidization catalyst mainly used in a thermal ring closure reaction and a dehydration condensing agent mainly used in a chemical ring closure method can be used.
Examples of the imidization catalyst include imidazole, 2-imidazole, 1,2-dimethylimidazole, 2-phenylimidazole, benzimidazole, isoquinoline, and substituted pyridine.
The amount of imidation catalyst used is not particularly limited with respect to a polyimide precursor such as polyamic acid, but preferably 0.05 to 10 weight, particularly 0.1 to 100 parts by weight of polyimide precursor such as polyamic acid. It can be used at a ratio of ˜2 wt. Since these form a polyimide film at a relatively low temperature, they can be used to avoid insufficient imidization.
The amount of the imidation catalyst used is not particularly limited, but preferably 1 to 80 parts by weight, more preferably 5 to 70 parts by weight, and still more preferably 10 to 100 parts by weight of the solvent. It is preferable to include 60 parts by mass.

As the dehydrating condensing agent, it is preferable to use a component selected from a ring closing catalyst and a dehydrating agent, or a combination of these ring closing catalyst and dehydrating agent.
As the ring-closing catalyst, any component can be used as long as it is a ring-closing catalyst used in a known chemical ring-closing method, and it is particularly preferable to use a component compatible with a solvent. For example, an aliphatic third catalyst such as trimethylamine or triethylamine is used. Examples of the dehydrating agent include heterocyclic tertiary amines such as tertiary amine, isoquinoline, pyridine, and betapicoline. As the dehydrating agent, any component can be used as long as it is a dehydrating agent used in a known chemical ring closure method. In particular, it is preferable to use a component that is compatible with a solvent. Examples thereof include aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride, and aromatic carboxylic acid anhydrides such as benzoic anhydride. I can do it.
The amount of the ring-closing catalyst is not particularly limited with respect to the polyimide precursor such as polyamic acid, but preferably 0.1 to 10 mol, more preferably 0.5 to 8 with respect to 1 mol of the polyimide precursor such as polyamic acid. It can be used in a molar ratio, in particular 1-6 molar.
Although the usage-amount is not specifically limited with respect to polyimide precursors, such as a polyamic acid, Preferably a dehydrating agent is 0.1-10 mol with respect to 1 mol of polyimide precursors, such as a polyamic acid, Furthermore, 0.3- It can be used in a proportion of 8 mol, in particular 1 to 6 mol.
The amount of the ring-closing catalyst contained in the solvent is not particularly limited, but is preferably 1 to 300 parts by weight, more preferably 5 to 200 parts by weight, and still more preferably 10 to 100 parts by weight with respect to 100 parts by weight of the solvent. In particular, the content of 15 to 80 parts by mass is preferable for the self-supporting film and the cured film properties.
The amount of the dehydrating agent used is not particularly limited with respect to the solvent, but is preferably 1 to 300 parts by weight, more preferably 5 to 5 parts, preferably 100 parts by weight of the solvent, preferably 100 parts by weight of the solvent. It is preferable for self-supporting film and cured film properties to contain 200 parts by weight, more preferably 10 to 100 parts by weight, particularly preferably 15 to 80 parts by weight.

As the solvent solution of the polyimide precursor or the solvent, a solvent containing a release agent can be used.
As the release agent, any self-supporting film obtained by casting on a support may be used as long as the release from the support is improved, and there is no problem with the characteristics of the resulting polyimide film. But it can be used.
Examples of the release agent include alkyl phosphate ester salts.
The amount of the release agent used is not particularly limited with respect to the polyimide precursor such as polyamic acid, but preferably 0.05 to 10 weight, particularly 0.1 to 0.1 weight with respect to 100 parts by mass of the polyimide precursor such as polyamic acid. It can be used in a proportion of 2 wt.
The amount of the release agent used with respect to the solvent is not particularly limited, but is preferably 1 to 80 parts by weight, more preferably 5 to 70 parts by weight, and even more preferably 10 to 60 parts with respect to 100 parts by weight of the solvent. It is preferable for including releasability to include parts by mass.

As the solvent, a solvent containing a surfactant can be used.
As the surfactant, any cast solution obtained by casting on a support may be used as long as it is less repellent than the support, and any surfactant can be used as long as there is no problem with the properties of the resulting polyimide film. I can do it.
Examples of the surfactant include silicone surfactants and fluorine surfactants.
The amount of the surfactant used is not particularly limited with respect to the polyimide precursor such as polyamic acid, but it is preferably 0.05 to 10 weight, particularly preferably 0.1 to 100 parts by weight of the polyimide precursor such as polyamic acid. It can be used at a ratio of ˜2 wt.
The amount of the surfactant used with respect to the solvent is not particularly limited, but preferably 1 to 80 parts by mass, more preferably 5 to 70 parts by mass, and still more preferably 10 to 100 parts by mass of the solvent. It is preferable to include 60 parts by mass for improving coatability.

A solvent containing particles can be used as the solvent solution of the polyimide precursor or the solvent interposed between the support and the solvent solution of the polyimide precursor to be cast.
Examples of the particles include inorganic particles and organic particles, and particles obtained by combining these.
Inorganic particles include fine particle titanium dioxide powder, silicon dioxide (silica) powder, magnesium oxide powder, aluminum oxide (alumina) powder, inorganic oxide powder such as zinc oxide powder, fine particle silicon nitride powder, titanium nitride powder. Inorganic nitride powder such as silicon carbide powder, inorganic carbide powder such as silicon carbide powder, and inorganic salt powder such as particulate calcium carbonate powder, calcium sulfate powder, and barium sulfate powder. These inorganic fine particles may be used in combination of two or more. In order to uniformly disperse these inorganic fine particles, a means known per se can be applied.
Examples of the organic particles include polyimide particles (one that is unnecessary or not completely dissolved in the solvent or solvent of the polyimide precursor), thermosetting resin particles, and the like.
Two or more kinds of particles can be used from the above-mentioned inorganic particles, organic particles, and composite particles thereof.

As an example of the production of the polyimide film of the present invention,
Using a film forming apparatus in which a single-layer or multi-layer extrusion die is installed, first, a solvent solution of a polyimide precursor is supplied to the die, and a single layer or a lip portion is supplied from a discharge port (lip portion) of the die. Extruded onto a thin film of solvent on a support (endless belt, drum, etc.) as a multilayered thin film to form a thin film with a uniform thickness of the solvent solution of the polyimide precursor, inside the casting furnace, polyimide Heat to a temperature at which imidation of the polyimide precursor of the thin film (cast solution) of the solvent solution of the precursor does not proceed completely and a temperature at which a part or most of the organic solvent can be removed, preferably 100 to 180 ° C. And for about 2 to 60 minutes, a part or most of the solvent is removed to create a self-supporting film, and the self-supporting film is peeled from the support,
If necessary, apply or spray a solution (for example, a surface treatment agent, a polyimide precursor, polyimide, etc.) on one or both sides of the self-supporting film, and further apply mainly if necessary. Dry for the purpose of removing the working solvent,
The polyimide film can be produced by subjecting the self-supporting film to a heat treatment to remove the remaining polyimide precursor organic solvent and the solvent and imidization.

  In the production of polyimide film, the support is formed by forming a solvent thin film on the support by a solvent thin film process, then forming a thin film of a polyimide precursor solvent solution on the solvent thin film, and then casting. Heated inside the furnace, the self-supporting film is peeled off from the support, and if necessary, if the solvent remains on the support, the remaining solvent is removed, and then the solvent thin film process The process of forming a thin film of the solvent on the support is continuously performed.

As the support, known materials can be used, but those having a surface made of a stainless steel material are preferable, and a stainless steel belt, a stainless steel roll or the like is used.
It is preferable that a thin film of a solvent can be uniformly formed on the surface of the support.

In the production of the polyimide film, as a method of forming a solvent thin film on the support, known methods can be used, for example, gravure coating method, spin coating method, silk screen method, dip coating method, spray coating method, Examples thereof include a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a known coating method such as sponge and cloth, and a spraying device such as a spray.
The solvent to be interposed between the support and the thin film of the solvent solution of the polyimide precursor to be cast may be in the form of a liquid film on the support, preferably in the form of a liquid film with a uniform thickness on the support. The thickness of the liquid film of the solvent may be selected so that the thin film (cast film) of the solvent solution of the polyimide precursor to be cast can be landed without any problem. Preferably, the solvent has a support area of 1 m. ² per range of 5 to 100 g, further a range of 10 to 80 g, it is preferable to particularly interposed range of 20 to 70 g.

In the production of the polyimide film, as a method for removing the solvent remaining on the support, a known method can be used, the solvent can be removed, and the support and the member that does not damage the surface of the support or the surface thereof are used. And a method of spraying a gas, a method of washing and removing with a liquid that can be easily evaporated and does not affect the production of polyimide.
For example, examples of the member include a porous material such as a sponge, and a natural or synthetic material such as a woven fabric such as cloth or an unemployed fabric.
The shape of the member may be a shape that does not damage the support and its surface, and examples thereof include a roll shape, a plate shape, and a rod shape.

In the production of polyimide film,
Furthermore, if necessary, a polyimide precursor solvent solution thin film (cast film) can be landed on the support without problems using a die for extrusion formation (for example, a polyimide precursor solvent solution thin film (cast film)). For the purpose of pressing onto the support)
A method using means such as blowing air or other gas using an air knife or the like from the landing position on the support of the thin film of the polyimide precursor solvent solution (cast film) on the support,
Also, the polyimide precursor solvent solution thin film (cast film) is positioned on the opposite side of the support from the landing position of the polyimide precursor solvent solution thin film (cast film) on the support. And a method using a means such as sucking the gas.

In the production of polyimide film,
The heat treatment of the self-supporting film is preferably fixed and heated with a pin type tenter, clip type tenter, metal or the like.
The heat treatment of the self-supporting film is performed first at a temperature of 200 ° C. to less than 300 ° C. for 1 minute to 60 minutes, and then at a temperature of 300 ° C. to less than 370 ° C. for 1 minute to 60 minutes. It is desirable to perform the third heat treatment at a maximum heating temperature of 350 ° C. to 580 ° C., preferably at 370 to 550 ° C. for 1 to 30 minutes. The said heat processing can be performed using well-known various apparatuses, such as a hot air furnace and an infrared heating furnace.

In the production of a polyimide film, a thin film layer of a solvent solution of a polyimide precursor is formed on the gas phase side of the thin film layer of the solvent.
The thin film layer of the solvent and the thin film (cast film) of the solvent solution of the polyimide precursor are overlapped until the self-supporting film is peeled off from the support, and the thin film solvent and the thin film polyimide precursor The solvent solution may not be mixed at all, or a part or all of the solvent solution may be mixed, and it is particularly preferable that a part or all of the solvent solution of the polyimide precursor and the solvent are mixed.

In the production of polyimide film,
When the solution is applied to one side or both sides of the self-supporting film, it is sufficient that the self-supporting film does not tear or crack when applied to the self-supporting film.
As a method for applying the solution to one side or both sides of the self-supporting film, a known method can be used, for example, gravure coating method, spin coating method, silk screen method, dip coating method, spray coating method, bar coating. Known coating methods such as a method, a knife coating method, a roll coating method, a blade coating method, and a die coating method can be exemplified.

Surface treatment agents that can be included in the solution applied to the self-supporting film include silane coupling agents, borane coupling agents, aluminum coupling agents, aluminum chelating agents, titanate coupling agents, and iron couplings. Examples include various coupling agents such as an agent and a copper coupling agent, and chelating agents.
The solvent can contain a surface treatment agent.

As a solvent to be interposed between the support and the solvent solution of the polyimide precursor to be cast, the strength of the self-supporting film is increased by using a solvent containing at least one additive component selected from an imidizing agent and a release agent. Improve,
During the period from when the self-supporting film is peeled off to the heat treatment, a solution is sprayed on one or both sides of the self-supporting film for the purpose of surface modification such as smoothness or adhesiveness, and then applied or immersed. Even when solution coating such as the above is performed, the self-supporting film is hardly cut or cracked, so that it can be used in a production method including a solution coating step on the self-supporting film.

  The thickness of the polyimide film used in the present invention is not particularly limited as long as it is appropriately selected depending on the purpose, but the thickness is 150 μm or less, preferably 5 to 120 μm, more preferably 6 to 50 μm, and still more preferably. It can be 7-25 micrometers, Most preferably, it can be 8-15.

  The polyimide film produced by the production method of the present invention is used for substrates for electronic and electric use, base substrates for liquid crystal displays, organic electroluminescence displays, electronic paper, solar cells, and various tape substrates. be able to.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

(Evaluation of cast state of organic solvent solution of polyamic acid on support)
The amic acid cast on a smooth metal support is dried at 150 ° C. for 7 minutes to produce a self-supporting film. The self-supporting film is foamed by air entrainment, and the amic acid solution shakes during landing. The presence or absence of deterioration in flatness due to the presence of streaks and the presence or absence of streaks due to cast instability are visually observed and evaluated.
○: The self-supporting film does not foam due to air entrapment, does not deteriorate flatness due to shaking of the amic acid solution at the time of landing, and does not cause streaks due to cast instability.
X: The self-supporting film has foaming due to air entrainment, the flatness is deteriorated due to shaking of the amic acid solution at the time of landing, or streaks are generated due to instability of cast.

(Experimental example 1) (Preparation of polyamic acid solution A)
A predetermined amount of N, N-dimethylacetamide (DMAc) is added to the polymerization tank, then monostearyl phosphate triethanolamine salt is added, and then 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. Then, p-phenylenediamine was added and polymerized at 30 ° C. for 10 hours to obtain a DMAc solution of polyamic acid having a polymer concentration of 18% by mass and a rotational viscosity of 1800 poise. 0.05 mol of 1,2-dimethylimidazole, which is an imidization catalyst, was added to the DMAc solution of this polyamic acid with respect to 1 mol of the amic acid in the polyamic acid, and the mixture was further stirred at 30 ° C. for 2 hours to obtain a polyamic acid solution A. It was.

(Experimental example 2)
A predetermined amount of N, N-dimethylacetamide (DMAc) is added to the polymerization tank, and then monostearyl phosphate triethanolamine salt is added, followed by 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. Then, p-phenylenediamine was added and polymerized at 30 ° C. for 10 hours to obtain a DMAc solution of polyamic acid having a polymer concentration of 18% by mass and a rotational viscosity of 1800 poise. To this DMAc solution of polyamic acid, 0.2 mol of 1,2-dimethylimidazole, which is an imidization catalyst, is added with respect to 1 mol of the amic acid in the polyamic acid and stirred at 30 ° C. for another 2 hours to obtain a polyamic acid solution B. It was.

(Experimental example 3) (Preparation of imidizing agent-containing solvent A)
Dimethylacetamide 500g was added to the separable flask which flowed nitrogen, acetic anhydride 375g and 1, 2- dimethylimidazole 125g were added, and the imidizing agent containing solvent A was prepared.

(Experimental example 4) (release agent-containing solvent B)
To a separable flask in which nitrogen was flowed, 990 g of dimethylacetamide was added, and 10 g of monostearyl phosphate ester triethanolamine salt was added to prepare a release agent-containing solvent B.

(Experimental example 5) (Surfactant-containing solvent C)
Dimethylacetamide 999.9g was added to the separable flask which flowed nitrogen, surfactant L7001 (product made from Toray Dow Corning) 0.1g was added, and surfactant-containing solvent C was prepared.

(Reference Example 1)
An amic acid solution A was cast on a smooth endless belt metal support using a T-die so that the film thickness after the heat treatment was 12.5 μm. The speed was increased while adjusting the discharge amount from the T die so as to be constant per unit area, and the speed at which air entrainment was confirmed by visual observation was confirmed.

Example 1
Dimethylacetamide was applied to a smooth endless belt metal support using a die coater so as to be 6 g / m ² . On a smooth endless belt metal support coated with dimethylacetamide, the amic acid solution A was cast using a T-die so that the film thickness after the heat treatment was 12.5 μm. The speed is increased while adjusting the discharge rate from the die coater and T die to be constant per unit area, and even when the casting speed is 3.3 times the limit speed of Reference Example 1, the air is visually observed. It was confirmed that stable casting without biting was possible.

(Example 2)
The imidizing agent-containing solvent A was applied to a smooth endless belt metal support using a die coater so as to be 6 g / m ² . The amic acid solution A was cast on a smooth endless belt metal support coated with the imidizing agent-containing solvent A using a T-die so that the film thickness after the heat treatment was 12.5 μm. The speed is increased while adjusting the discharge rate from the die coater and T die to be constant per unit area, and even when the casting speed is 3.3 times the limit speed of Reference Example 1, the air is visually observed. It was confirmed that stable casting without biting was possible.
The obtained self-supporting film had a solvent content of 36% by mass, an imidization ratio of 15% on the air side, and 32% on the support side.
Furthermore, even when dimethylacetamide was applied to the self-supporting film, the film was not cut or cracked.

(Reference Example 2)
Except that the imidizing agent-containing solvent A was not applied to the support, the same operation as in Example 2 was performed, and the solvent content of the self-supporting film obtained under the same drying conditions was 39% by mass, imidization. The rate was 8% on the gas side and 16% on the support side. When dimethylacetamide was applied to the self-supporting film, breakage of the film and generation of cracks were observed.

(Example 3)
The release agent-containing solvent B was applied to a smooth endless belt metal support using a die coater so as to be 6 g / m ² . The amic acid solution B was cast on a smooth endless belt metal support coated with the release agent-containing solvent B using a T-die so that the film thickness after the heat treatment was 12.5 μm. The speed is increased while adjusting the discharge rate from the die coater and T die to be constant per unit area, and even when the casting speed is 3.3 times the limit speed of Reference Example 1, the air is visually observed. It was confirmed that stable casting without biting was possible.
Moreover, the peeling force from the metal support of the self-supporting film was 0.5 N / m, and it was easily peelable from the metal support.

(Reference Example 3)
Except that the release agent-containing solvent B was not applied to the support, the same operation as in Example 3 was performed, and the peeling force from the metal support of the self-supporting film obtained under the same drying conditions was 4. The peelability from the metal support was poor.

Example 4
The surfactant-containing solvent C was applied to a smooth endless belt metal support using a die coater so as to be 6 g / m ² . The amic acid solution A was cast on a smooth endless belt metal support coated with the surfactant-containing solvent C using a T-die so that the film thickness after the heat treatment was 12.5 μm. The speed is increased while adjusting the discharge rate from the die coater and T die to be constant per unit area, and even when the casting speed is 3.3 times the limit speed of Reference Example 1, the air is visually observed. It was confirmed that stable casting without biting was possible.

Claims (9)

A method for producing a polyimide film in which a solvent solution of a polyimide precursor is cast on a support, the solvent in the solution is removed, the film is peeled from the support as a self-supporting film, and the self-supporting film is heated to imidize And
A method for producing a polyimide film, comprising casting a solvent having compatibility with a polyimide precursor between a support and a solvent solution of a polyimide precursor to be cast. Solvent interposed between the solvent solution of the support and the cast is polyimide precursor, producing a polyimide film according to claim 1, characterized in that a 5 to 100 g / m ^2.   The solvent interposed between the support and the solvent solution of the polyimide precursor to be cast contains at least one additive component selected from an imidizing agent, a release agent, and a surfactant. The manufacturing method of the polyimide film of Claim 2.   The solvent intervening between the support and the solvent solution of the polyimide precursor to be cast is 10 to 80 parts by mass of the imidization catalyst, 10 to 80 parts by mass of the dehydrating condensing agent, and 10 parts by mass of the release agent. The manufacturing method of the polyimide film of Claim 1 or Claim 2 containing the addition component chosen from -80 mass parts and 10-80 mass parts of surfactant, and a compounding quantity.   The polyimide precursor is a polyimide precursor obtained from an acid component containing a 3,3 ′, 4,4′-biphenyltetracarboxylic acid component and a diamine component containing p-phenylenediamine. The manufacturing method of the polyimide film of any one of 1-4.   The polyimide according to any one of claims 1 to 5, wherein the solvent interposed between the support and the solvent solution of the polyimide precursor to be cast has compatibility with the solvent of the polyimide precursor. A method for producing a film.   The solvent solution of a polyimide precursor contains 5-50 mass% of polyimide precursors in the solvent solution of a polyimide precursor, The polyimide film of any one of Claims 1-6 characterized by the above-mentioned. Production method.   The method for producing a polyimide film according to claim 1, wherein the solvent solution of the polyimide precursor has a solution viscosity in the range of 500 to 5000 poise.   The thickness of a polyimide film is the range of 5-15 micrometers, The manufacturing method of the polyimide film of any one of Claims 1-6 characterized by the above-mentioned.