TW201936715A - Porous polyimide film original fabric, method for producing the same and composition having a tensile strength of 45 MPa or more as specified by the ASTM standard D638 - Google Patents

Abstract

A problem to be solved by this invention is to provide a porous polyimide film original fabric excellent in tensile strength and bending strength, a method for producing the same, and a composition suitable for being used for producing the same. The solution of this invention is a porous polyimide film original fabric having a tensile strength of 45 MPa or more as specified by the ASTM standard D638. A porous polyimide film original fabric which comprises polyimide containing a structural unit represented by the following formula (1-1) and a structural unit represented by the following formula (1-2), wherein A11 and A12 each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B11 and B12 each independently represent a divalent diamine residue derived from an aromatic diamine. At least one selected from the group consisting of A12 and B12 contains a divalent spacer group in its structure.

Description

Porous polyimide film raw cloth roll (original film), its manufacturing method and composition

The present invention relates to a raw roll of porous polyimide film excellent in tensile strength and flexural strength, a method for producing the same, and a composition suitable for use in the production.

Polyimide resins are excellent in mechanical strength, chemical stability, and heat resistance. Porous polyimide films composed of polyimide resins having such excellent characteristics are attracting attention in various applications.
For example, Patent Document 1 describes that by containing a polyimide resin and a non-crosslinked resin other than a polyimide resin, a porous polyimide film containing only a polyimide resin can suppress turtles. Cracking of the porous polyimide film.
However, the porous polyfluorene imide film described in Patent Document 1 is weak in the applied force at the time of manufacture, and can be manufactured only in a single sheet, which deteriorates manufacturing suitability.

[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-183273

[Questions to be Solved by the Invention]

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a porous polyimide film raw cloth roll excellent in tensile strength and flexural strength, a method for producing the same, and a composition suitable for the production. .

[Means to solve the problem]

The present inventors have found that even when a polyimide film containing polyimide containing a structural unit of a specific structure is used as a porous material, it is excellent in tensile strength and flexural strength, and it can be prevented from being caused when the original fabric roll is manufactured. Occurrence of film cracking due to the application of tension, winding, or the like can be made into a rectangular (eg, at least 1 m or more) raw fabric roll with excellent winding properties, and the present invention is finally completed. That is, the present invention is as follows.

A first aspect of the present invention is a porous polyimide film roll, which has a tensile strength of 45 MPa or more as specified by ASTM standard D638.

A second aspect of the present invention is a porous polyimide film raw cloth roll, which includes polyimide, and the polyimide system includes a structural unit represented by the following formula (1-1) and the following The constituent unit represented by the formula (1-2).

(In the above formula, A ¹¹ and A ¹² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ¹¹ and B ¹² each independently represent a divalent diamine residue derived from an aromatic diamine. Group, at least one selected from the group consisting of A ¹² and B ¹² includes a divalent spacer group in its structure).

A third aspect of the present invention is a porous polyimide film raw cloth roll, which includes polyimide, and the polyimide system includes a constituent unit represented by the following formula (2-1) and the following The constituent unit represented by the formula (2-2).

(In the above formula, A ²¹ and A ²² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ²¹ and B ²² each independently represent a divalent diamine residue derived from an aromatic diamine. And A ²² and B ²² satisfy a condition selected from the group consisting of the following (I) and (II).
(I) The electron affinity of the aromatic tetracarboxylic anhydride derived from A ²² is 2.6 eV or less.
(II) The aromatic diamine derived from B ^{22 and} the aromatic diamine derived from B ²¹ are different aromatic diamines, and have a solubility in water at 40 ° C. of 0.1 g / L or more).

The fourth aspect of the present invention is a manufacturing method, which is a method for manufacturing a porous polyimide film raw cloth roll, and is characterized by comprising:
After applying a composition comprising a polyimide precursor, that is, polyamic acid and fine particles, to form a coating film on a substrate, the coating film is dried to form a coating film forming step including a film containing the polyimide precursor and fine particles. , And the firing step for firing the above coating,
The firing step is a fine particle removing step for removing the fine particles, or further includes the fine particle removing step.
The peeling of the film from the substrate or the roll of the manufactured porous polyimide film original cloth before the firing step, after the firing step, or after the fine particle removing step after the film forming step is included. step,
The tensile strength of the porous polyimide film raw fabric roll specified in ASTM specification D638 is 45 MPa or more.

A fifth aspect of the present invention is a composition containing fine particles, which contains polyamic acid, and the polyamino acid contains a structural unit represented by the following formula (3-1) and the following formula (3-2 The structural unit represented by) includes the structural unit represented by the following formula (4-1) and the structural unit represented by the following formula (4-2).

(In the above formula, A ¹¹ , A ¹² , B ¹¹ and B ^{12 are} synonymous with these abbreviations in the above formulae (1-1) and (1-2), and are selected from the group consisting of A ¹² and B ¹² At least one of them has a divalent spacer in its structure).

(In the above formula, A ²¹ , A ²² , B ²¹ and B ^{22 are} synonymous with these abbreviations in the above formulae (2-1) and (2-2), and A ²² and B ²² are selected from the group consisting of ) And (II).

[Inventive effect]

The porous polyimide film raw cloth roll of the present invention has excellent tensile strength and bending strength, excellent manufacturing suitability, and suppresses film breakage caused by the force of stretching, winding, etc. during the manufacture of the original cloth roll. Occurs and can be made into a raw cloth roll with excellent winding property of a rectangular shape (for example, at least 1 m or more).
The production method of the present invention is suitable for producing the aforementioned porous polyimide film roll.
The composition of the present invention can be suitably used in the production of the above-mentioned porous polyimide film raw fabric roll, and is particularly suitably used in the production by a roll-to-roll manufacturing method.

Hereinafter, although the embodiments of the present invention are described in detail, the present invention is not limited to the following embodiments, and can be implemented by adding appropriate changes within the scope of the object of the present invention.

≪Polypolyimide film roll cloth≫
The tensile strength specified in ASTM Specification D638 of the porous polyimide film raw fabric roll of the first aspect is 45 MPa or more.
When the tensile strength is 45 MPa or more, it is possible to suppress the occurrence of film cracking due to the application of tension or the like during the production of the original fabric roll, and it is possible to obtain a rectangular original fabric roll having excellent rollability.
The tensile strength is preferably 70 MPa or more, more preferably 80 MPa or more, even more preferably 90 MPa or more, and particularly preferably 100 MPa or more.
The upper limit of the tensile strength is not particularly limited as long as the effects of the present invention are not impaired. The tensile strength may be 300 MPa or less, and usually 200 MPa or less.

The bending strength specified by ASTM specification D790 of the porous polyimide film raw cloth roll is preferably 60 MPa or more.
When the above-mentioned bending strength is 60 MPa or more, it is possible to suppress the occurrence of film cracking due to an applied force such as stretching during the production of the original fabric roll, and it is possible to obtain a rectangular original fabric roll having excellent winding properties.
The bending strength is preferably 70 MPa or more, more preferably 80 MPa or more, even more preferably 90 MPa or more, particularly preferably 100 MPa or more, and most preferably 110 MPa or more.
The upper limit of the bending strength is not particularly limited as long as the effect of the present invention is not impaired. The bending strength may be 400 MPa or less, and usually 300 MPa or less.

Regarding the first roll of the porous polyimide film roll, from the viewpoint of tensile strength and flexural strength, it is preferable to include the following expressions (1-1) and (1-2) The constituent unit of polyimide.
Regarding the porous polyimide film raw cloth roll of the first aspect, from the viewpoint of tensile strength and bending strength, it is also preferable to include the constituent unit represented by the formula (2-1) described later and ( 2-2) Polyimide as a constituent unit.

Regarding the second aspect of the porous polyimide film raw cloth roll, the polyimide includes a constituent unit represented by the formula (1-1) and a constituent unit represented by the formula (1-2).

(In the above formula, A ¹¹ and A ¹² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ¹¹ and B ¹² each independently represent a divalent diamine residue derived from an aromatic diamine. Group, at least one selected from the group consisting of A ¹² and B ¹² includes a divalent spacer group in its structure).

At least one selected from the group consisting of A ¹² and B ¹² , and since the structure includes a divalent spacer, it is suitable for achieving tensile strength (e.g., 45 MPa or more) and flexural strength (e.g., 45 MPa or more) of the original fabric roll. 60MPa or more).
From the viewpoint of more surely achieving tensile strength and bending strength, it is preferred that A ¹² include a divalent spacer in its structure.

An aromatic tetracarboxylic dianhydride derived from a tetravalent aromatic group of A ¹¹ and A ¹² and at least one selected from the group consisting of A ¹² and B ¹² as long as a divalent spacer is included in its structure, that is, The aromatic tetracarboxylic dianhydride which has been conventionally used as a synthetic raw material of polyamic acid can be appropriately selected.

Suitable specific examples of the aromatic tetracarboxylic dianhydride include 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride and bis (2,3-dicarboxyphenyl) methane dianhydride. , Bis (3,4-dicarboxyphenyl) methane dianhydride, 9,9-bisphthalic anhydride hydrazone, 3,3 ', 4,4'-diphenylphosphonium tetracarboxylic dianhydride, 2, 2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) ) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoro Propane dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) Ether dianhydride, 2,2 ', 3,3'-benzophenonetetracarboxylic dianhydride, 4,4- (p-phenylene dioxy) diphthalic dianhydride, 4,4- ( m-phenylene dioxy) diphthalic dianhydride, pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,3 , 3 ', 4'-biphenyltetracarboxylic dianhydride, 2,2,6,6-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4, 5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10- 苝Dianhydride, 2,3,6,7-tetracarboxylic dianhydride onions, 1,2,7,8-phenanthrene tetracarboxylic dianhydride and the like. These tetracarboxylic dianhydrides may be used alone or in combination of two or more.

The aromatic diamine derived from the divalent diamine residues of B ¹¹ and B ¹² is at least one selected from the group consisting of A ¹² and B ¹² as long as the structure includes a divalent spacer, that is, The aromatic diamine can be appropriately selected from conventional aromatic diamines used as synthetic raw materials of polyamic acid.

Examples of the aromatic diamine include a diamine-based compound having a benzene ring or 2 or more and 10 or less benzene rings and / or a condensed polycyclic ring having two amine groups. The benzene ring or polycyclic ring in the aromatic diamine may have a substituent. Specifically, there are phenylenediamine and its derivatives, diamino biphenyl compounds and its derivatives, diamine diphenyl compounds and its derivatives, diamino triphenyl compounds and its derivatives, and diamines. Naphthalene and its derivative, aminophenylaminoindenane and its derivative, diaminotetraphenyl compound and its derivative, diaminohexaphenyl compound and its derivative, cardo type fluorene diamine derivative.

Phenylenediamines include m-phenylenediamine (MDA), p-phenylenediamine (PDA), and the like. The phenylenediamine derivative is a diamine bonded to an alkyl group such as a methyl group or an ethyl group. Phenylenediamine derivatives are, for example, 2,4-diaminotoluene, 2,4-triphenyldiamine, and the like.

The diamino biphenyl compound is a compound in which two amino phenyl groups are bonded to each other. Examples of the diaminobiphenyl compound include 4,4'-diaminobiphenyl and 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl.

A diaminodiphenyl compound is a compound in which two aminophenyl groups are bonded through a divalent linking group. The divalent linking group is an oxy group (-O-), a sulfofluorenyl group, a thio group (-S-), an alkylene group or a derivative group thereof, an imino group, or an azo group
(-N = N-), phosphine oxide group (-P (= O) R-, R: hydrogen atom or monovalent organic group bonded to phosphorus atom), amido group (-CONH-), urea base
(-NH-CO-NH-) and the like. The alkylene group is a group having 1 to 6 carbon atoms, and its derivative group is a group in which one or more hydrogen atoms of the alkylene group are substituted with a halogen atom or the like.

Examples of the diaminodiphenyl compound include 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenyl. Ether, 3,3'-diaminodiphenylphosphonium, 3,4'-diaminodiphenylphosphonium, 4,4'-diaminodiphenylphosphonium, 3,3'-diaminediphenyl Phenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 3,3'-di Amino diphenyl ketone, 3,4'-diamino diphenyl ketone, 2,2-bis (p-aminophenyl) propane, 2,2'-bis (p-aminophenyl) hexa Fluoropropane, 4-methyl-2,4-bis (p-aminophenyl) -1-pentene, 4-methyl-2,4-bis (p-aminophenyl) -2-pentene , Iminodiphenylamine, 4-methyl-2,4-bis (p-aminophenyl) pentane, bis (p-aminophenyl) phosphine oxide, 4,4'-diamino group Nitrobenzene, 4,4'-diaminodiphenylurea, 4,4'-diaminodiphenylamidamine, 1,4-bis (4-aminophenoxy) benzene, 1,3- Bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] fluorene, bis [4- (3-aminophenoxy) phenyl] fluorene, 2 , 2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, and the like.

A diaminotriphenyl compound is a compound in which two aminophenyl groups and one phenyl group are bonded through a divalent linking group. The linking group is the same as the diaminodiphenyl compound. Examples of the diamino triphenyl compound include 1,3-bis (m-aminophenoxy) benzene, 1,3-bis (p-aminophenoxy) benzene, and 1,4-bis (p-aminophenoxy) benzene and the like.

Examples of the diaminonaphthalene include 1,5-diaminonaphthalene and 2,6-diaminonaphthalene.

Examples of aminophenylaminoindenane include 5-amino-1- (p-aminophenyl) -1,3,3-trimethylindane and 6-amino-1- ( p-aminophenyl) -1,3,3-trimethylindane.

Examples of the diaminotetraphenyl compound include 4,4'-bis (p-aminophenoxy) biphenyl and 2,2'-bis [p- (p'-aminophenoxy) Phenyl] propane, 2,2'-bis [p- (p'-aminophenoxy) biphenyl] propane, 2,2'-bis [p- (m-aminophenoxy) phenyl] Benzophenone and so on.

Examples of cardo-type fluorene diamine derivatives include 9,9-bis (4-aminophenyl) fluorene and the like.

The aromatic diamine may be a hydrogen atom of such a diamine by a compound substituted with at least one kind of substituent selected from the group consisting of a halogen atom, a methyl group, a methoxy group, a cyano group, and a phenyl group.

Examples of the divalent spacer include an ether bond, a thioether bond, a carbonyl group, an alkylene group, a fluorinated alkylene group, a sulfofluorenyl group, and a fluorenyl group. A divalent group of a hydrogen atom) and the like.
The alkylene group is preferably a linear or branched alkylene group having 1 to 5 carbon atoms. Specific examples of the linear or branched alkylene group having 1 to 5 carbon atoms include methylene, ethylidene, propylidene, and dimethylmethylene.
The fluorinated alkylene group is preferably a linear or branched fluorinated alkylene group having 1 to 5 carbon atoms. Specific examples of the linear or branched fluorinated alkylene group having 1 to 5 carbon atoms include difluoromethylene, tetrafluoroethylene, bis (trifluoromethyl) methylene, etc. .

When A ¹² includes a divalent spacer in its structure, A ¹² can be represented by the following formula (1-2-1).
When B ¹² includes a divalent spacer in its structure, B ¹² can be represented by the following formula (1-2-2).

(In the above formula, A ¹²¹ and A ¹²² each independently represent a trivalent aromatic group, B ¹²¹ and B ¹²² each independently represent a divalent aromatic group, X ¹ and X ² each independently represent a divalent spacer group, and * represents a bond unit).
Examples of the trivalent aromatic group include benzenetriyl, naphthalenetriyl, and the like. Among them, benzenetriyl is preferred. As a benzenetriyl group, a benzene-1,2,4-triyl group is preferable.
Examples of the divalent aromatic group include a phenylene group and a naphthyl group. Among them, phenylene is preferred. As the phenylene group, a p-phenylene group or an m-phenylene group is preferable, and a p-phenylene group is more preferable.

When A ¹² includes a divalent spacer in its structure, specific examples of the aromatic tetracarboxylic anhydride derived from the tetravalent aromatic group of A ¹² include 1,1-bis (2,3-dicarboxyphenyl). ) Ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 9,9-bisphthalic anhydride fluorene (BPAF) 3,3 ', 4,4'-diphenylphosphonium tetracarboxylic dianhydride (DSDA), 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2 , 3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride (6FDA), 2 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic acid Dianhydride (BTDA), bis (3,4-dicarboxyphenyl) ether dianhydride (ODPA), bis (2,3-dicarboxyphenyl) ether dianhydride, 2,2 ', 3,3'-di Benzophenone tetracarboxylic dianhydride, 4,4- (p-phenylene dioxy) diphthalic acid dianhydride, 4,4- (m-phenylene dioxy) diphthalic acid dianhydride Wait.

When B ¹² contains a divalent spacer in its structure, specific examples of the aromatic diamine derived from the divalent diamine residue of B ¹² include 3,3'-diaminodiphenyl ether, 3 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (ODA), 3,3'-diaminodiphenylphosphonium, 3,4'-diaminodiphenyl Phenylphosphonium, 4,4'-diaminodiphenylphosphonium (DDS), 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4 ' -Diaminodiphenylmethane (DDM), 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl ketone, 3,4'-diaminodiphenyl Ketone, 2,2-bis (p-aminophenyl) propane, 2,2'-bis (p-aminophenyl) hexafluoropropane, 4-methyl-2,4-bis (p-amino (Phenyl) -1-pentene, 4-methyl-2,4-bis (p-aminophenyl) -2-pentene, iminodiphenylamine, 4-methyl-2,4-bis ( p-aminophenyl) pentane, bis (p-aminophenyl) phosphine oxide, 4,4'-diaminoazobenzene, 4,4'-diaminodiphenylurea, 4, 4'-diaminodiphenylphosphonium amine, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis ( 3-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) Phenyl) phenyl] fluorene, bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2 -Bis [4- (4-aminophenoxy) phenyl] hexafluoropropane and the like.

The content of the constituent unit represented by the above formula (1-1) in the polyimide is preferably 40 mol% or more, and more preferably 50 mol% from the viewpoint of tensile strength and flexural strength. Above, still more preferably 60 mol% or more.
The upper limit of the content of the constituent unit represented by the formula (1-1) is not particularly limited as long as the effect of the present invention is not impaired. The content of the constituent unit represented by the formula (1-1) may be 99 mol% or less, and may be 95 mol% or less, and may be generally 90 mol% or less.

The content of the constituent unit represented by the above formula (1-2) in the polyimide is preferably 60 mol% or less, and more preferably 50 mol% from the viewpoint of tensile strength and flexural strength. Hereinafter, it is more preferably 40 mol% or less.
The lower limit of the content of the constituent unit represented by the formula (1-2) is not particularly limited as long as the effect of the present invention is not impaired. The content of the constituent unit represented by the formula (1-2) may be 1 mol% or more, and may also be 5 mol% or more. In general, it may be 10 mol% or more.

The third aspect of the porous polyimide film raw fabric roll includes polyimide including the constituent units represented by the following formulae (2-1) and (2-2).

(In the above formula, A ²¹ and A ²² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ²¹ and B ²² each independently represent a divalent diamine residue derived from an aromatic diamine. A ²² and B ²² satisfy the condition of at least one selected from the group consisting of the following (I) and (II).
(I) The electron affinity of the aromatic tetracarboxylic anhydride derived from A ²² is 2.6 eV or less.
(II) The aromatic diamine derived from B ^{22 and} the aromatic diamine derived from B ²¹ are different aromatic diamines, and have a solubility in water at 40 ° C. of 0.1 g / L or more).
When A ²² and B ²² satisfy at least one condition selected from the group consisting of the above (I) and (II), a tensile strength (for example, 45 MPa or more) and a bending strength (for example, 45 MPa or more) suitable for the original fabric roll can be achieved (For example, 60 MPa or more).
From the viewpoint of more surely achieving tensile strength and bending strength, it is preferable that A ²² satisfies the condition (I) described above.

As long as A ²² and B ²² satisfy at least one selected from the group consisting of the above-mentioned (I) and (II), the aromatic tetracarboxylic dianhydride derived from the tetravalent aromatic group of A ²¹ and A ²² is derived. Under the conditions, an aromatic tetracarboxylic dianhydride which has been conventionally used as a synthetic raw material of polyamic acid can be appropriately selected.
Specific examples of the aromatic tetracarboxylic dianhydride derived from the tetravalent aromatic group of A ²¹ and A ^{22 are} specific examples of the aromatic tetracarboxylic dianhydride derived from the tetravalent aromatic group of A ¹¹ and A ¹² example. The same compounds as those mentioned above can be mentioned.

Aromatic diamines derived from the divalent diamine residues of B ¹¹ and B ¹² as long as A ²² and B ²² satisfy at least one selected from the group consisting of the above (I) and (II) It can be appropriately selected from aromatic diamines which have been conventionally used as synthetic raw materials of polyamic acid.
As specific examples of the relevant derived B ¹¹ and B ¹² of the divalent diamine residue of an aromatic diamine, as derived from the specific embodiments relating to B ¹¹ and B ¹² of the divalent diamine residue of an aromatic diamine, include The same compound as the aforementioned compound.

Regarding the above (I), the Ea system derived from the aromatic tetracarboxylic anhydride of A ²² is described in the document CONSULTANTS BUREAU
POLYIMIDES Thermally Stable Polymers (by MI Bessonov, MM Koton, VV Kudryavtsev, LA Laius), VM Svetlichnyi, KK Kalnin'sh, VV Kudryavtsev, and MM Kotton, Dokl. Akad. Nauk., 237,612-615 (1977), etc.
The electron affinity (Ea) of the aromatic tetracarboxylic anhydride from which A ²² is derived is preferably 2.3 eV or less.
The lower limit of Ea is not particularly limited. Ea may be 1.0 eV or more, and may generally be 1.3 eV or more.

The structure of the aromatic tetracarboxylic anhydride derived from A ²² and its electronic affinity are shown below. The aromatic tetracarboxylic anhydride derived from A ²² is not limited to the following compounds.
In the following examples, the values in parentheses are electron affinity.

Regarding the above (II), "the solubility in water at 40 ° C is 0.1 g / L or more" means the limit amount (g) of 1 L (liter) of water in which the aromatic diamine derived from B ²² is dissolved at 40 ° C. This value can be easily retrieved by SciFinder (registered trademark) known as a search service based on a database of chemical abstracts and the like. Here, among the solubility under various conditions, you can use the Advanced Chemistry Development (ACD / Labs) Software V11.02 (
Copyright 1994-2011 ACD / Labs) calculated pH value of 7.
The solubility of the aromatic diamine derived from B ²² is preferably 0.5 g / L or more, and more preferably 1.0 g / L or more.
The upper limit of solubility is not particularly limited. The solubility can be 500 g / L or less, and usually 400 g / L or less.

Although the structure of the aromatic diamine derived from B ²² and its solubility in water at 40 ° C. are exemplified below, the present invention is not limited to these.
In the following examples, the values in parentheses are the solubility in water at 40 ° C.

The content of the constituent unit represented by the above formula (2-1) in the polyimide is preferably 40 mol% or more, and more preferably 50 mol% from the viewpoint of tensile strength and flexural strength. Above, still more preferably 60 mol% or more.
The upper limit of the content of the constituent unit represented by the formula (2-1) is not particularly limited as long as the effect of the present invention is not impaired. The content of the constituent unit represented by the formula (2-1) may be 99 mol% or less, and may also be 95 mol% or less, and may generally be 90 mol% or less.

The content of the constituent unit represented by the above formula (2-2) of the polyimide is preferably 60 mol% or less, and more preferably 50 mol% from the viewpoint of tensile strength and flexural strength. Hereinafter, it is more preferably 40 mol% or less.
The lower limit of the content of the constituent unit represented by the above formula (2-2) is not particularly limited as long as the effect of the present invention is not impaired. The content of the constituent unit represented by the formula (2-2) may be 1 mol% or more, and may also be 5 mol% or more. In general, it may be 10 mol% or more.

The mass average molecular weight (Mw) of the polyimide contained in the porous polyimide film raw fabric rolls of the first to third aspects is not particularly limited as long as the effect of the present invention is not impaired. Regarding the mass average molecular weight (Mw) of the polyimide contained in the porous polyimide film raw fabric rolls of the first to third aspects, the tensile strength and flexural strength are preferably 5,000 or more. , More preferably 8000 or more, even more preferably 10,000 or more, and particularly preferably 15,000 or more.
When the polyimide precursor solution described later contains an organic solvent, the Mw of the polyimide is not particularly limited as long as the effect of the present invention is not impaired. From the viewpoint of tensile strength and flexural strength, the Mw of the polyimide may be 30,000 or more, and preferably 50,000 or more.
The upper limit of the Mw of the polyimide is not particularly limited as long as the effect of the present invention is not impaired. The Mw of the polyimide is preferably 100,000 or less, and more preferably 80,000 or less.
In this specification, the mass average molecular weight (Mw) is a measured value in terms of polystyrene by gel permeation chromatography (GPC).

It is preferable that the porous polyimide film raw cloth roll of the first to third aspects has a plurality of openings formed irregularly on the surface of the raw cloth roll and an irregular plurality formed on the back of the original cloth roll. The openings are porous.
Regarding the porous polyimide film raw cloth rolls of the first to third aspects, it is preferable that the porous cloth has communication holes that communicate the surface of the raw cloth roll and the back surface of the raw cloth roll. Specifically, it is preferable that at least a part of the plurality of openings formed on the surface of the original fabric roll and at least a part of the plurality of openings formed on the back surface of the original fabric roll communicate with the inside of the polyimide film.

The porous polyimide film is used, for example, as a separator that passes liquid and / or ionic molecules or holds an electrolytic solution, or as a filter that collects or separates specific substances. From the viewpoint of the connectivity suitable for these applications, the porosity of the porous polyfluorene imine film rolls of the first to third aspects is preferably 50% or more, more preferably 55% or more, More preferably, it is 60% or more, and particularly preferable is 65% or more.
The upper limit of the porosity is not particularly limited. However, from the viewpoint of strength, the porosity is preferably 90% or less, and more preferably 80% or less.

The porosity indicates, for example, the proportion of voids per unit volume of the original fabric roll. The porosity can be calculated, for example, by the following formula (A).
Void ratio (%) = {Volume of test piece (cm ³ )-[Weight of test piece (g) / Specific gravity of polyimide (g / cm ³ )]) / Volume of test piece (cm ³ ) × 100 ･ ･ ･ (A)

As described later, the desired porosity can be achieved by appropriately adjusting the particle size or content of the fine particles used in the production of the original fabric roll.

The porous polyimide film raw fabric rolls of the first to third aspects are excellent in tensile strength and flexural strength. Therefore, it is possible to suppress the occurrence of film cracking due to the application of tension, winding, or the like during the manufacture of the original fabric roll. As a result, a rectangular raw fabric roll can be manufactured. There are no particular restrictions on the film length of the porous polyfluoreneimide film rolls of the first to third aspects. The film length is preferably 1 m or more, more preferably 5 m or more, even more preferably 10 m or more, particularly preferably 30 m or more, and most preferably 40 m or more.
The upper limit of the film length is not particularly limited. The length of the film can be 2000m or less, and usually 1000m or less.
The film width as the roll of the original cloth is not particularly limited and can be appropriately set.
The thickness of the raw fabric roll is not particularly limited. The thickness is preferably 1 μm or more and 500 μm or less, more preferably 3 μm or more and 200 μm or less, even more preferably 5 μm or more and 100 μm or less, and particularly preferably 7 μm or more and 80 μm or less.

Regarding the first to third aspect of the porous polyimide film roll, it has excellent tensile strength and flexural strength, and because of its excellent rollability, it can be wound to a diameter of 2.5cm (1 inch) or more and 25cm (10cm) Cores). The porous polyimide film raw fabric rolls of the first to third aspects are preferably formed by winding a roll core having a diameter of 5 cm (2 inches) or more and 10 cm (4 inches) or less. Thereby, the winding length of each roll of the original cloth roll is increased, and the transportation and storage cost is suppressed.
The material of the winding core is not particularly limited. Specific examples of the material of the roll core include stainless steel (for example, SUS), polyethylene terephthalate (PET), and the like.

≫Application of Porous Polyimide Film Rolls≫
The porous polyimide film raw cloth roll described above can provide various separators (such as separators for secondary batteries such as nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries), various filters, and fuel cell electrolytes. Membrane, low dielectric material.
The porous polyimide film original fabric roll described above has excellent tensile strength and flexural strength, and can suppress the occurrence of film breakage caused by the force of stretching and winding during the production of the original fabric roll. A rectangular roll (for example, at least 1 m or more) of an original cloth roll having excellent winding properties is suitable for manufacturing a battery or a filter device.

≫Manufacturing method of raw roll of porous polyimide film≫
The fourth aspect of the method for producing a raw roll of porous polyimide film includes a composition comprising a polyimide precursor, that is, polyamic acid and fine particles (hereinafter, also simply referred to as " Polyimide precursor solution ") After being applied to the substrate to form a coating film, the coating film is dried to form a coating film forming step including the polyimide precursor and fine particles, and firing the aforementioned coating film step,
The firing step is a fine particle removing step for removing the fine particles, or further includes the fine particle removing step.
The peeling of the film from the substrate or the roll of the manufactured porous polyimide film original cloth before the firing step, after the firing step, or after the fine particle removing step after the film forming step is included. step,
The tensile strength of the porous polyimide film raw fabric roll specified in ASTM specification D638 is 45 MPa or more.

As a preferable range of the said tensile strength, the porous polyimide film raw cloth roll concerning a 1st aspect is the same as the said range.
The preferred range of the bending strength specified in the ASTM specification D790 of the above-mentioned porous polyimide film original cloth roll, and the above-mentioned range of the porous polyimide film original cloth roll related to the first aspect, the same.
From the viewpoint of productivity, the production of the porous polyimide film raw fabric roll is preferably roll-to-roll.

〈Film formation step〉
(Polyamic acid)
The polyimide precursor is preferably a polyamidic acid containing a structural unit represented by formula (3-1) and a structural unit represented by formula (3-2), or a composition represented by formula (4-1) The unit and the polyamic acid represented by the structural unit represented by the formula (4-2).

(In the above formula, A ¹¹ , A ¹² , B ¹¹ and B ¹² are synonymous with these abbreviations in formula (1-1) and formula (1-2), and are selected from the group consisting of A ¹² and B ¹² At least one of the groups consists of a divalent spacer in its structure).

(In the above formula, A ²¹ , A ²² , B ^21, and B ²² are synonymous with these abbreviations in formula (2-1) and formula (2-2), and A ²² and B ²² are selected from the group consisting of Conditions of at least one of the groups consisting of I) and (II)).

The composition according to the fifth aspect includes fine particles described later, a polyamic acid containing a structural unit represented by the following formula (3-1) and a structural unit represented by the following formula (3-2), or Polyamic acid having a constitutional unit represented by the following formula (4-1) and a constitutional unit represented by the following formula (4-2).
The composition according to the fifth aspect can be suitably used as a polyimide precursor solution in the production method according to the fourth aspect. As a result, it is suitable for producing a raw roll of porous polyimide film having a tensile strength of 45 MPa or more as specified by ASTM standard D638.

The content of the constitutional unit represented by formula (3-1) or the constitutional unit represented by formula (4-1) in the polyamic acid is preferably 40 mol% or more, and more preferably 50 mol% or more. Even more preferably, it is 60 mol% or more.
The upper limit of the content of the structural unit represented by formula (3-1) or the structural unit represented by formula (4-1) is not particularly limited as long as the effect of the present invention is not impaired. The content of the constituent unit represented by the formula (3-1) or the constituent unit represented by the formula (4-1) may be 99 mol% or less, or 95 mol% or less, and generally 90 mol% or less. .

The content of the constituent unit represented by the above formula (3-2) or (4-2) of the polyamic acid is preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 40 mol% or less.
The lower limit value of the content of the constituent unit represented by the formula (3-2) or (4-2) is not particularly limited as long as the effect of the present invention is not impaired. The content of the constituent unit represented by formula (3-2) or the constituent unit represented by formula (4-2) may be 1 mol% or more, and may also be 5 mol% or more, and usually 10 mol% or more .

The polyfluorene acid of the polyfluorene imide precursor can be obtained by polymerizing an aromatic tetracarboxylic dianhydride and an aromatic diamine. The amount of the aromatic tetracarboxylic dianhydride and the aromatic diamine used is not particularly limited. With respect to the amount of the aromatic diamine used for the aromatic tetracarboxylic dianhydride 1 mol, it is preferred to use 0.50 mol to 1.50 mol, more preferably 0.60 mol to 1.30 mol, and particularly preferred 0.70. Above Mohr and below 1.20 Mor.

The aromatic tetracarboxylic dianhydride can be appropriately selected from aromatic tetracarboxylic dianhydrides which have been conventionally used as raw materials for polyamic acid synthesis. The aromatic tetracarboxylic dianhydride can be used in combination of two or more kinds.
Specific examples of the aromatic tetracarboxylic dianhydride, and specific examples of the aromatic tetracarboxylic dianhydride derived from the tetravalent aromatic group of A ¹¹ and A ¹² include the same compounds as the aforementioned compounds.

The aromatic diamine can be appropriately selected from aromatic diamines which have been conventionally used as synthetic raw materials of polyamic acid. The aromatic diamine can be used in combination of two or more kinds.
As specific examples of the aromatic diamine, specific examples of the aromatic diamine derived from the divalent diamine residues of B ¹¹ and B ¹² include the same compounds as the aforementioned compounds.

The method for producing polyamic acid is not particularly limited. For example, a known method such as a method of reacting an aromatic tetracarboxylic dianhydride and an aromatic diamine in an organic solvent can be used.

The reaction of an aromatic tetracarboxylic dianhydride and an aromatic diamine is usually performed in an organic solvent. The organic solvent used in the reaction of aromatic tetracarboxylic dianhydride and aromatic diamine can dissolve aromatic tetracarboxylic dianhydride and aromatic diamine. If it is not compatible with aromatic tetracarboxylic dianhydride and aromatic diamine The organic solvent for the amine reaction is not particularly limited. The organic solvents can be used alone or in combination of two or more.

Examples of the organic solvent used in the reaction between the aromatic tetracarboxylic dianhydride and the aromatic diamine include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, and N, N-diamine. Ethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylcaprolactam, N, N, N ', N'-tetramethyl Nitrogen-containing polar solvents such as urea; β-propiolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, etc. Dimethyl sulfene; acetonitrile; fatty acid esters such as ethyl lactate and butyl lactate; diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dioxane, tetrahydrofuran, methyl cellulose Ethers such as acetate, ethyl cellosolve acetate; phenolic solvents such as cresols. These organic solvents can be used alone or in combination of two or more. Among them, a combination of the above-mentioned nitrogen-containing polar solvent and a lactone-based polar solvent is preferred. The amount of the organic solvent used is not particularly limited. The amount of the organic solvent used is preferably an amount in which the content of the produced polyamic acid is 5 mass% or more and 50 mass% or less.

Among these organic solvents, from the viewpoint of the solubility of the produced polyamic acid, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, and N, N-diethyl are preferred. Ethylamine, N, N-dimethylformamide, N, N-diethylformamide, N-methylcaprolactam, N, N, N ', N'-tetramethylurea, etc. A polar solvent containing nitrogen. From the viewpoint of film-forming properties, it can be used as a mixed solvent in which a lactone-based polar solvent such as γ-butyrolactone is added. The lactone-based polar solvent is preferably added in an amount of 1% by mass or more and 20% by mass or less with respect to the entire organic solvent, and more preferably 5% by mass or more and 15% by mass or less.

The polymerization temperature is generally -10 ° C to 120 ° C, and preferably 5 ° C to 30 ° C. Although the polymerization time varies depending on the composition of the raw materials used, it is usually 3 hours to 24 hours. The intrinsic viscosity of the polyamic acid solution obtained under such conditions is preferably in the range of 1,000 cP (centipoise) or more and 100,000 cP or less, and more preferably in the range of 5,000 cP or more and 70,000 cP or less.

The Mw of the polyamic acid is not particularly limited as long as the effect of the present invention is not impaired. From the viewpoint of the tensile strength and bending strength of the original fabric roll, the Mw of the polyamic acid is preferably 5,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, particularly preferably More than 15,000.
When the polyfluorene imide precursor solution contains an organic solvent, the Mw of the polyphosphonic acid is not particularly limited as long as the effect of the present invention is not impaired. The Mw of the polyamic acid may be 30,000 or more, and preferably 50,000 or more, from the viewpoint of tensile strength and bending strength of the original fabric roll produced.
The upper limit of Mw of the polyamic acid is not particularly limited as long as the effect of the present invention is not impaired. The Mw of the polyamic acid is preferably 100,000 or less, and more preferably 80,000 or less.

(Fine particles)
As the material of the microparticles contained in the polyimide precursor solution, if it is insoluble in the contained solvent, the material that can be removed from the porous polyimide film roll in the subsequent microparticle removal step is not A particularly limited material may be a known material.
When the material of the fine particles is an inorganic material, if the inorganic fine particles can be removed by a method such as chemical treatment or heating, the material of the inorganic fine particles is not particularly limited. Examples of the material of the inorganic fine particles include metal oxides such as silicon dioxide, calcium carbonate, titanium oxide, and aluminum oxide (Al ₂ O ₃ ). Examples of preferred inorganic fine particles include fine particles of silica such as calcium carbonate and colloidal silica.

When the material of the fine particles is an organic material, examples of the material of the organic fine particles include high molecular weight olefin polymers (polypropylene, polyethylene, polybutadiene, polyisoprene, polytetrafluoroethylene, etc.), and polystyrene. Such as aromatic vinyl polymers, acrylic resins (acrylic acid, methyl acrylate, methyl methacrylate, isobutyl methacrylate, polymethylmethacrylate (PMMA), etc.), epoxy resins, and fibers Organic polymers such as cellulose, polyvinyl alcohol, polyvinyl butyral, polyester, and polyether. These organic polymers may be copolymers (for example, a copolymer of methmethacrylate and styrene, a copolymer of acrylic acid and styrene). In addition, it can be used in combination with organic fine particles of different materials.

The ratio of the mass of the fine particles to the total mass of the polyamic acid and the fine particles in the polyimide precursor solution is preferably 35% by mass or more, and more preferably 40% by mass or more.
The upper limit of the ratio of the mass of the fine particles is not particularly limited. The ratio of the mass of the fine particles is preferably 90% by mass or less, more preferably 85% by mass or less from the viewpoint of strength.

The shape of the fine particles is not particularly limited, and may be spherical particles or plate-like particles. The fine particles are preferably spherical particles, and more preferably those having a high true spherical ratio.
The particle diameter (average diameter or median diameter) of the fine particles is not particularly limited. For example, the average diameter or median diameter is preferably 10 nm to 2000 nm, more preferably 50 nm to 1500 nm, and even more preferably 100 nm to 1,000 nm.
The particle size distribution index (d25 / d75) of the fine particles is preferably 1 or more and 6 or less, more preferably 1 or more and 5 or less, and even more preferably 1 or more and 3 or less.
Here, d25 and d75 represent particle diameters with cumulative degrees of particle size distribution of 25% and 75%, respectively, and d25 is the larger particle diameter.

Examples of the solvent that can be contained in the polyimide precursor solution include water, an aqueous solution of an organic solvent, and an organic solvent.
Specific examples of the organic solvent include organic solvents exemplified as a solvent used for the reaction of an aromatic tetracarboxylic dianhydride and an aromatic diamine. The organic solvents may be used alone or in combination of two or more.
Examples of the organic solvent in the case of an aqueous solution of an organic solvent include a polar solvent and a water-soluble solvent. Specific examples of the polar solvent or the water-soluble solvent include methyl alcohol, ethyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and 2-methyl-1-propanol. , 1-pentanol, 2-pentanol, 4-methyl-2-pentanol, 1,1-dimethylethanol, 2,2-dimethyl-1-propanol, tetrahydrofurfuryl alcohol, etc. Alcohols; Glycols such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and diethylene glycol. The organic solvent is preferably an alcohol.
When B ²² satisfies the above-mentioned (II), the solvent that can be contained in the polyimide precursor solution is preferably water or an aqueous solution of the organic solvent.
When organic fine particles are used as the fine particles, the solvent is preferably water or an aqueous solution of the organic solvent.
When an inorganic fine particle is used as the fine particle, as the organic solvent that can be contained in the polyimide precursor solution, polyamic acid or polyimide can be dissolved, and an organic solvent in which the inorganic fine particles are not dissolved is preferred.
The solid content concentration of the polyfluorene imide precursor solution is preferably 5 mass% or more and 50 mass% or less, and more preferably 10 mass% or more and 40 mass% or less.

(Other ingredients)
The polyimide precursor solution may include a dispersant. In addition to the above components, the polyimide precursor solution is used for the purpose of antistatic, flame retardancy, low-temperature firing, release property, and coating property improvement, and may include antistatic if necessary. Appropriate and well-known components such as agents, flame retardants, chemical fluorinated imidizing agents, condensation agents, release agents, and surface modifiers.

Examples of the substrate include films such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), and SUS substrates. PET films are preferred.
As a method of applying (for example, coating) a polyfluorene imide precursor solution to the above substrate, forming a coating film, and then drying (pre-baking) the coating film to form a film, examples thereof include normal pressure or vacuum at 0 ° C Above 120 ° C or lower (preferably 0 ° C or higher and 90 ° C or lower), more preferably a method of forming a coating film by drying at 10 ° C or higher and 100 ° C or lower (more preferably 10 ° C or higher and 90 ° C or lower) at normal pressure.
The thickness as a coating film is not specifically limited. The thickness of the coating film is preferably 1 μm or more and 800 μm or less, more preferably 3 μm or more and 200 μm or less, even more preferably 5 μm or more and 100 μm or less, and particularly preferably 7 μm or more and 80 μm or less.

<Baking step>
By firing the above-mentioned film containing a polyimide precursor, that is, a polyamic acid, the polyimide can be closed-looped to form a polyimide, which can be a polyimide film.
For example, in the firing step, the polyamine acid containing the structural unit represented by the formula (3-1) and the structural unit represented by the formula (3-2) can be closed to the structural unit represented by the formula (1-1). And the polyimide having the constitutional unit represented by (1-2), the polyamine having the constitutional unit represented by the formula (4-1) and the constitutional unit represented by the formula (4-2) can be closed-looped in the inclusion formula ( Polyimide of the structural unit represented by 2-1) and the structural unit represented by formula (2-2).
The firing temperature is preferably from 120 ° C to 500 ° C, and more preferably from 150 ° C to 450 ° C.
The firing conditions may be, for example, a method of increasing the temperature from room temperature to 420 ° C for 3 hours and then maintaining the temperature at 420 ° C for 20 minutes, or increasing the temperature stepwise from room temperature in 20 ° C increments (holding each stage for 20 minutes). It is a stepwise drying-hot-liminization method to 420 ° C, and finally held at 420 ° C for 20 minutes.

(Fine particle removal step)
The manufacturing method may further include a fine particle removing step.
The inorganic fine particles can be removed by contacting an aqueous solution of hydrofluoric acid (HF) or the like with inorganic fine particles such as silicon dioxide to dissolve the inorganic fine particles. When the inorganic fine particles are calcium carbonate, an aqueous solution of hydrofluoric acid may be used instead of an aqueous solution of hydrochloric acid.
When the fine particles are organic fine particles and non-crosslinked resin fine particles, the polyimide film is not dissolved, and the non-crosslinked resin particles can be dissolved and removed by using the non-crosslinked resin particles as a soluble organic solvent. Examples of such organic solvents include ethers such as tetrahydrofuran; aromatics such as toluene; ketones such as acetone; and esters such as ethyl acetate. Among these, ethers such as tetrahydrofuran are preferably used, and tetrahydrofuran is more preferably used.

When the firing step includes the fine particle removal step, the fine particles are preferably organic fine particles.
If the organic material of the organic fine particles is a material that decomposes at a lower temperature than the polyimide, it will not give thermal damage to the polyimide, and only the organic fine particles will disappear.
For example, resin fine particles composed of a linear polymer or a known depolymerizable polymer may be mentioned. Generally, a linear polymer is a polymer that randomly cuts the molecular chain of the polymer during thermal decomposition, and a depolymerizable polymer is a polymer that polymer decomposes into monomers during thermal decomposition. All of them disappear from the polyimide film by being decomposed into a low molecular weight body or CO ₂ . The decomposition temperature of the resin fine particles used is preferably, for example, 200 ° C or higher and 400 ° C or lower.

＜ Stripping step ＞
The manufacturing method includes peeling the film or the manufactured porous polyimide film from the substrate before the firing step, after the firing step, or after the fine particle removing step after the film forming step. Step of peeling the original cloth roll.
In the above-mentioned production method, when the roll of the porous polyimide film raw cloth is rectangular (for example, 1 m or more), from the viewpoint of productivity, it is preferable to further include a roll wound to a diameter of 2.5 cm or more and 25 cm or less. Core steps.

[Example]

Hereinafter, although the present invention will be described in more detail by showing examples, the scope of the present invention is not limited to these examples.

[Synthesis example]
The aromatic tetracarboxylic anhydride shown in the following Table 1 is reacted with an aromatic diamine to obtain a polyamino acid containing an acid anhydride residue and a diamine residue in a composition ratio (mole%) in the following Table 1. 1 to 3 and Comparative Polyamines 1 and 2.
In the following Table 1, "solubility" means solubility (g / L) with respect to water at 40 ° C.

[Example 1]
Using a homogenizer, 42 g of spherical silica (median average particle diameter 280 nm, particle size distribution index (d25 / d75) 1.5 or less) was uniformly dispersed in 42 g of dimethylacetamide (DMAC) to obtain silicon dioxide. 84 g of dispersion.
A DMAC solution of polyamino acid 1 obtained above (concentration of polyamino acid 1 at 20% by mass) was prepared, and 52.5 g of the solution was mixed with 84 g of the above-mentioned silica dispersion liquid and 13.5 g of DMAC. (Namely, manufactured by Thinky Co., Ltd.) and uniformly mixed to obtain the polyfluorene imide precursor solution (composition) of Example 1 (for mass ratio, spherical silica: polyfluoric acid = 80: 20, volume ratio Spherical silica: Polyamic acid = 73:27).

[Comparative Examples 1 and 2]
Replacing the DMAC solution of Polyamic Acid 1 with DMAC solution (Comparison of 20% by mass of Polyamic Acid 1) and Polyamic Acid 2 DMAC solution (Comparing Polyamine) Except that the concentration of the acid 2 was 20% by mass), the procedure was performed in the same manner as in Example 1 to obtain the polyimide precursor solutions of Comparative Examples 1 and 2.

[Example 2]
Water dispersion of polystyrene particles containing polystyrene (PS) spherical particles (median average particle size 260 nm, particle size distribution index (d25 / d75) 1.5 or less, hereinafter referred to as "polystyrene particles") Liquid (40% by mass) and the aqueous solution of polyamidic acid 1 obtained above (concentration of 15% by mass of polyamic acid 1), and further added pure water, and uniformly mixed so that the solid content concentration became 23% by mass, The polyimide precursor solution of Example 2 was obtained (for mass ratio, polystyrene particles: polyamidic acid = 60: 40, and for volume ratio, polystyrene particles: polyamidic acid = 68: 32).

[Example 3]
Instead of the aqueous solution of polyamino acid 1 obtained above (concentration of polyamino acid 1 of 15% by mass), the above-mentioned aqueous solution of polyamino acid 1 / IPA (isopropanol) (polyamino acid) Except for a concentration of 15% by mass and water / IPA = 9/1 (mass ratio)), the other procedures were performed in the same manner as in Example 2 to obtain a polyimide precursor solution of Example 3.

[Example 4]
Instead of the aqueous solution of polyamino acid 1 obtained above (concentration of polyamino acid 1 of 15% by mass), the aqueous solution of polyamino acid 1 obtained above / NMP (N-methylpyrrolidone) aqueous solution (polyfluorene) was used instead. A polyimide precursor solution of Example 4 was obtained in the same manner as in Example 2 except that the concentration of the amino acid 1 was 15% by mass and water / NMP = 9/1 (mass ratio)).

[Examples 5 and 6 and Comparative Example 3]
Instead of replacing the aqueous solution of the polyamidic acid 1 separately, use the aqueous solution of the polyamidic acid 2 (concentration of 15% by mass of the polyamic acid 2), and the aqueous solution of the polyamic acid 3 (the polyamic acid 3) The concentration was 15% by mass), and the aqueous solution of Polyamidine 2 was compared (the concentration of Polyamidine 2 was 15% by mass). The other procedures were performed in the same manner as in Example 2 to obtain the polyimide of Examples 5 and 6. A precursor solution, and a polyfluorene imide precursor solution of Comparative Example 3.

[Example 7]
An aqueous dispersion (21% by mass) of a non-crosslinked styrene-acrylic acid copolymer (hereinafter referred to simply as "A / St") containing an average particle diameter of 0.1 μm and the polyamino acid 1 obtained above were uniformly mixed. Aqueous solution (concentration of 21% by mass of polyamic acid 1) to obtain the polyimide precursor solution of Example 7 (for mass ratio, A / St: polyamidic acid = 50: 50, for volume ratio, Is A / St: polyamidic acid = 57:43).

[Example 8]
An aqueous dispersion (40% by mass) of calcium carbonate fine particles (average particle diameter of 700 nm) obtained in a production method described later, and an aqueous solution of polyamino acid 1 (concentration of polyamino acid 1 of 30% by mass) are uniformly mixed. ) To obtain the polyfluorene imide precursor solution of Example 8 (for a mass ratio, about calcium carbonate particles: polyfluoric acid = 73:27, and for a volume ratio, it is calcium carbonate particles: polyfluoric acid = 40 : 60).

[Dispersion of calcium carbonate fine particles]
Add 10 g of unmodified calcium carbonate fine particles (hexagonal calcite type, average particle size: 700 nm) to 50 g of isopropyl alcohol, and stir with a stirrer for 1 hour while cooling with ice water to prepare the isopropyl alcohol suspension of calcium carbonate particles. liquid. On the other hand, 0.2 g of adipic acid was added to 23 g of isopropyl alcohol, and the mixture was stirred for 10 minutes to completely dissolve it to prepare an isopropyl alcohol solution. The above-mentioned isopropyl alcohol suspension and the above-mentioned isopropyl alcohol solution were stirred at room temperature for 2 hours to obtain a slurry containing calcium carbonate fine particles of surface-modified adipic acid and isopropyl alcohol. A Tongshan funnel (manufactured by Kiriyama Co., Ltd.) and a cellulose filter paper with a particle diameter of 1 μm were used to collect the slurry, and then the filtrate was dried at 120 ° C. for 1 hour to obtain calcium carbonate fine particles having a surface modified adipic acid. 7.2 g of this calcium carbonate fine particles was added to 10.8 g of pure water, and homogenization was performed at a pulverization force of 20% for 40 seconds, and then homogenization was performed at a pulverization force of 30% for 40 seconds to obtain a calcium carbonate microparticle dispersion.

(Film formation step and peeling step)
The polyimide precursor solutions (compositions) of Examples 1 to 8 and Comparative Examples 1 to 3 obtained above were applied to a PET film using a coating device to obtain a final film thickness (porous polyimide film original cloth). The film thickness of the roll was applied so as to be 25 μm to form a coating film. The PET film forming the coating film was put into a baking oven and dried at 80 ° C. for 5 minutes to form a film.
The obtained film was peeled from the PET film.

＜ Film crack resistance test ＞
The film cracking condition of the peeled film was defined as "film crack resistance (film)" and evaluated visually according to the following criteria. The results are shown in Table 2 below.
○: No film rupture.
×: The strength of the coating becomes weak and the film breaks.
XX: The strength of the film was very weak, and a large number of film cracks occurred.
For the film formed from the polyfluorene imide precursor solution of Comparative Examples 1 to 3, film cracking occurred, and the subsequent firing step and fine particle removal step were not performed.

(Step of firing the film after peeling)
Using a firing furnace, the above-mentioned film was fired at a furnace temperature of 420 ° C for 5 minutes (however, Example 7 was 380 ° C for 5 minutes) to form a polyimide film.
For the film formed from the polyfluorene imide precursor solution of Examples 2 to 6, the firing step also has a fine particle removal step, and the polystyrene particles can be burned by the firing to obtain a film thickness of 25 μm. The raw polyimide film rolls of Examples 2 to 6 were rolled.

(Fine particle removal step)
A polyimide film formed from the polyimide precursor solution of Example 1 was immersed in a 10% by mass aqueous solution of hydrogen fluoride (HF) for 10 minutes to dissolve the silicon dioxide to obtain a film having a thickness of 25 μm. Raw porous polyimide film roll of Example 1.
The polyimide film formed from the polyimide precursor solution of Example 7 was impregnated with tetrahydrofuran (THF) in place of a 10% by mass aqueous solution of hydrofluoric acid instead of A /. St was dissolved, and the porous polyimide film raw fabric roll of Example 7 was obtained.
Regarding the polyimide film formed from the polyimide precursor solution of Example 8, except that instead of 10% by mass of an aqueous solution of hydrofluoric acid, 10% by mass of hydrochloric acid was used instead, and the carbonic acid was further impregnated. Calcium was dissolved, and the porous polyimide film roll of Example 8 was obtained.
As a result of measuring the porosity of the porous polyimide film raw fabric rolls of Examples 1 to 6 obtained as described above, any of the raw fabric rolls was in a range of 60% to 70%. Examples 7 and 8 are in a range of 50% to 60%.

＜ Tensile strength and flexural strength test ＞
The test pieces of the porous polyimide film raw cloth rolls of Examples 1 to 8 and Comparative Examples 1 to 3 obtained as described above were measured for tensile strength and flexural strength according to the following standard method (measurement device: EZ-TEST / CE (made by Shimadzu Corporation)).
Tensile strength: ASTM D638
Flexural modulus of elasticity: ASTM D790
The results are shown in Table 2 below.

From the results shown in Table 2 above, it is clear that using the so-called requirements of "constitutional unit represented by formula (3-1) and structural unit represented by formula (3-2)" and "inclusive formula (4-1) The constitutional unit and the constitutional unit represented by formula (4-2) "Comparative examples 1 to 3 of the comparative polyamines 1 and 2 whose requirements are not satisfied are all coating and drying, and the strength of the film after peeling is weak. The membrane rupture occurred.
The raw rolls of porous polyimide film of Comparative Examples 1 to 3 all did not satisfy the tensile strength of 45 MPa or more and the flexural strength of 60 MPa or more. Using the porous polyfluorene imide film raw fabric rolls of Comparative Examples 1 to 3, it was not possible to produce a rectangular (eg, 1 m or more) raw fabric roll.
On the other hand, when using the so-called requirements of "the structural unit represented by the inclusion formula (3-1) and the structural unit represented by the formula (3-2)" and the "constituent unit represented by the inclusion formula (4-1) and the formula (4 -2) The constituent units shown in Examples 1 to 8 of any one of the polyamic acids 1 to 3 of at least one of the so-called requirements are coating and drying, and the film of the film after peeling does not occur. The film was formed into a rectangular shape having a length of 40 m.
The raw rolls of porous polyimide film of Examples 1 to 8 all satisfy tensile strength of 45 MPa or more, and flexural strength of 60 MPa or more (60 MPa or more), and have excellent tensile strength and flexural strength. The porous polyimide film raw fabric rolls of Examples 1 to 8 can be wound into a 3 inch diameter core, and a raw roll of 40 m in length can be manufactured.

Example 1 using polyamic acid 1 having a content of 60 mol% or less of the constituent unit represented by the formula (3-2) or the constituent unit represented by the formula (4-2), and using the formula (3-2) As shown in the comparison of the sixth embodiment of the constitutional unit or the polyamic acid 3 having a constitutional unit represented by the formula (4-2) whose content exceeds 60 mol%, it is understood that the constitutional unit or the formula (3-2) 4-2) If the content of the constituent unit is 60 mol% or less, the tensile strength and flexural strength are excellent.

Claims (16)

A raw roll of porous polyimide film having a tensile strength of 45 MPa or more as specified by ASTM specification D638. For example, the porous polyimide film raw fabric roll of claim 1, wherein the bending strength specified by ASTM standard D790 is 60 MPa or more. For example, the porous polyimide film raw cloth roll of claim 1 or 2 includes polyimide, and the polyimide system includes a structural unit represented by the following formula (1-1) and the following formula ( 1-2) indicates the constituent units, (In the above formula, A ¹¹ and A ¹² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ¹¹ and B ¹² each independently represent a divalent diamine residue derived from an aromatic diamine. Group, at least one selected from the group consisting of A ¹² and B ¹² includes a divalent spacer group in its structure). For example, the porous polyimide film raw cloth roll of claim 1 or 2 includes polyimide, and the polyimide system includes a structural unit represented by the following formula (2-1) and the following formula ( 2-2) the constituent units indicated, (In the above formula, A ²¹ and A ²² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ²¹ and B ²² each independently represent a divalent diamine residue derived from an aromatic diamine. A ²² and B ²² satisfy the condition selected from the group consisting of the following (I) and (II): (I) the electron affinity of the aromatic tetracarboxylic anhydride derived from A ²² is 2.6 eV The following; (II) the aromatic diamine derived from B ^{22 and} the aromatic diamine derived from B ²¹ are different aromatic diamines, and the solubility in water at 40 ° C. is 0.1 g / L or more). A raw roll of porous polyimide film includes polyimide, and the polyimide system includes a constituent unit represented by the following formula (1-1) and a unit represented by the following formula (1-2) Constituent units, (In the above formula, A ¹¹ and A ¹² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ¹¹ and B ¹² each independently represent a divalent diamine residue derived from an aromatic diamine. Group, at least one selected from the group consisting of A ¹² and B ¹² includes a divalent spacer group in its structure). A raw roll of porous polyimide film includes polyimide, and the polyimide system includes a structural unit represented by the following formula (2-1) and a component represented by the following formula (2-2) Constituent units, (In the above formula, A ²¹ and A ²² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ²¹ and B ²² each independently represent a divalent diamine residue derived from an aromatic diamine. A ²² and B ²² satisfy the condition selected from the group consisting of the following (I) and (II): (I) the electron affinity of the aromatic tetracarboxylic anhydride derived from A ²² is 2.6 eV The following; (II) the aromatic diamine derived from B ^{22 and} the aromatic diamine derived from B ²¹ are different aromatic diamines, and the solubility in water at 40 ° C. is 0.1 g / L or more). For example, the porous polyimide film raw cloth roll of claim 5 or 6, wherein the content of the constituent unit represented by the above formula (1-2) or (2-2) of the polyimide is 60 mol %the following. For example, the porous polyimide film roll of claim 1 or 2, wherein the film length is 1 m or more. For example, the original porous polyimide film roll of claim 1 or 2 is formed by winding a core with a diameter of 2.5 cm or more and 25 cm or less. For example, the porous polyfluorene imide film roll of claim 1 or 2 has a void ratio of 60% by mass or more. A manufacturing method, which is a method for manufacturing a raw roll of porous polyimide film, comprising: After applying a composition comprising a polyimide precursor, that is, polyamic acid and fine particles, to form a coating film on a substrate, the aforementioned coating film is dried to form a film forming step including a film containing the polyimide precursor and fine particles. And firing steps for firing the aforementioned film, The firing step is a fine particle removing step for removing the fine particles, or further includes the fine particle removing step. Before the firing step after the aforementioned film forming step, after the firing step, or after the fine particle removing step, including peeling the aforementioned film from the substrate or peeling of the manufactured porous polyimide film original fabric roll step, The tensile strength specified in ASTM specification D638 of the aforementioned porous polyimide film raw fabric roll is 45 MPa or more. The method according to claim 11, wherein in the porous polyimide film, the bending strength specified by ASTM standard D790 is 70 MPa or more. The manufacturing method according to claim 11 or 12, further comprising the aforementioned porous polyimide film raw cloth roll having a film length of 1 m or more, and winding the aforementioned porous polyimide film raw cloth roll around 2.5 cm in diameter Steps for winding cores above 25cm. For example, the manufacturing method of claim 11 or 12, wherein the particle size distribution index (d25 / d75) of the aforementioned microparticles is 1 or more and 6 or less, and d25 and d75 represent the cumulative degree of the particle size distribution with particle diameters of 25% and 75%, respectively. , D25 is the larger particle diameter. The manufacturing method according to claim 11 or 12, wherein when the firing step has the fine particle removing step, the fine particles are organic fine particles. A composition containing fine particles, which comprises polyamidic acid, which comprises a structural unit represented by the following formula (3-1) and a structural unit represented by the following formula (3-2), or The structural unit represented by the following formula (4-1) and the structural unit represented by the following formula (4-2), (In the above formula, A ¹¹ and A ¹² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ¹¹ and B ¹² each independently represent a divalent diamine residue derived from an aromatic diamine. Base, at least one selected from the group consisting of A ¹² and B ¹² includes a divalent spacer in its structure) (In the above formula, A ²¹ and A ²² each independently represent a tetravalent aromatic group derived from an acid anhydride containing an aromatic tetracarboxylic anhydride, and B ²¹ and B ²² each independently represent a divalent diamine residue derived from an aromatic diamine. A ²² and B ²² satisfy at least one condition selected from the group consisting of the following (I) and (II). (I) The electron affinity of the aromatic tetracarboxylic anhydride derived from A ²² is 2.6 eV. The following; (II) the aromatic diamine derived from B ^{22 and} the aromatic diamine derived from B ²¹ are different aromatic diamines, and the solubility in water at 40 ° C. is 0.1 g / L or more).