JPWO2015080158A1 - Polyimide precursor composition, polyimide production method, polyimide, polyimide film, and substrate - Google Patents

Abstract

The present invention relates to a polyimide precursor composition comprising a polyimide precursor and an imidazole compound, wherein the content of the imidazole compound is less than 4 mol with respect to 1 mol of the repeating unit of the polyimide precursor. .

Description

  The present invention provides a solution composition (polyimide precursor composition) containing a polyimide precursor that provides a polyimide having a small thickness direction retardation (retardation), excellent mechanical properties, and excellent transparency. It relates to a manufacturing method. The present invention also relates to a polyimide, a polyimide film, and a substrate that are excellent in transparency, have a small thickness direction retardation, and are excellent in mechanical properties.

  In recent years, with the arrival of an advanced information society, development of optical materials such as a liquid crystal alignment film and a protective film for a color filter in the display device field, such as an optical fiber and an optical waveguide in the optical communication field, is progressing. In particular, in the field of display devices, a plastic substrate that is lightweight and excellent in flexibility as a substitute for a glass substrate has been studied, and a display that can be bent and rolled has been actively developed. For this reason, there is a demand for higher performance optical materials that can be used for such applications.

  Aromatic polyimide is essentially yellowish brown due to intramolecular conjugation and the formation of charge transfer complexes. For this reason, as a means to suppress coloration, for example, introduction of fluorine atoms into the molecule, imparting flexibility to the main chain, introduction of bulky groups as side chains, etc. inhibits intramolecular conjugation and charge transfer complex formation. Thus, a method for expressing transparency has been proposed.

  In addition, a method for expressing transparency by using a semi-alicyclic or fully alicyclic polyimide that does not form a charge transfer complex in principle has been proposed.

  For example, Patent Documents 1 to 3 disclose semi-alicyclic polyimides having high transparency using an aromatic tetracarboxylic dianhydride as a tetracarboxylic acid component and an alicyclic diamine as a diamine component.

  Further, for example, Patent Documents 4 to 7 disclose various highly translucent semi-alicyclic polyimides using an alicyclic tetracarboxylic dianhydride as a tetracarboxylic acid component and an aromatic diamine as a diamine component. Has been.

  Non-Patent Document 1 discloses, as a tetracarboxylic acid component, norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic. Polyimides using acid dianhydrides are disclosed. Further, norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride used here is 6 It is described that it contains various stereoisomers. Patent Document 8 also discloses norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid as a tetracarboxylic acid component. Polyimides using dianhydrides are disclosed.

  However, depending on applications, particularly in the field of display devices and the like, in addition to high transparency, it is desired to reduce the thickness direction retardation. By passing through a film having a large thickness direction retardation, there are cases in which colors are not displayed correctly, color bleeding and viewing angle are narrowed. Therefore, a polyimide film having a small thickness direction retardation is required particularly in the field of display devices and the like.

  On the other hand, Patent Document 9 discloses a polyimide formed by heating a coating solution obtained by blending a polyimide precursor (polyamic acid) with an imidazoline compound and / or an imidazole compound. More specifically, in Example 1, 2,4-dimethyl is added to a polyamic acid solution obtained from 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride and 4,4′-diaminobiphenyl ether. A solution to which imidazoline has been added is applied onto a substrate and heated at 200 ° C. for 1 hour to obtain an aromatic polyimide film having a thickness of 1000 mm (0.1 μm). In Example 2, a solution obtained by adding 2-ethylimidazoline and 1,2-dimethylimidazole to a solution of polyamic acid obtained from pyromellitic dianhydride and 4,4′-diaminobiphenyl ether was applied onto a substrate. An aromatic polyimide film having a thickness of 800 mm (0.08 μm) is obtained by heating at 150 ° C. for 1 hour. In Patent Document 9, by adding an imidazoline-based compound and / or an imidazole-based compound, the remarkable brown coloration is avoided, and a liquid crystal display element with high light transmittance and excellent transparency can be obtained. It is described. However, the light transmittance at a wavelength of 400 nm of the liquid crystal display element using the polyimide film (liquid crystal alignment film) of Example 1 is 82% (polyimide film thickness: 0.1 μm), and the polyimide film of Example 2 (liquid crystal alignment film). The light transmittance at a wavelength of 400 nm of the liquid crystal display element using the above is 83% (polyimide film thickness: 0.08 μm), and this polyimide does not have sufficient transparency.

  In addition, as a method for producing an aromatic polyimide having low transparency, Patent Document 10 discloses a polyimide precursor resin and a curing accelerator for a polyimide precursor resin such as imidazole and N-methylimidazole dissolved in an organic polar solvent. A method for forming a polyimide resin layer is disclosed in which a polyimide precursor resin-containing solution is applied onto a substrate, followed by drying and imidization to complete the formation of a polyimide resin layer within a range of 280 to 380 ° C., It is described that the thermal expansion coefficient can be controlled to be low by using these curing accelerators. Patent Document 10 also describes that a curing accelerator having a boiling point exceeding 120 ° C. is preferably used, and that a boiling point not exceeding the upper limit temperature of heat treatment is preferably selected. In addition, it is described that a curing accelerator having a boiling point of, for example, 400 ° C. or higher has a higher ratio of remaining in the polyimide resin layer after imidization and tends to affect the function of the polyimide resin layer.

JP 2003-192787 A JP 2004-83814 A JP 2008-308550 A JP 2003-168800 A International Publication No. 2008/146737 JP 2002-69179 A JP 2002-146021 A International Publication No. 2011/099518 JP-A 61-267030 JP 2008-115378 A

Polymer Papers, Vol. 68, no. 3, P.I. 127-131 (2011)

  The present invention has been made in view of the situation as described above, and is a polyimide having excellent transparency and having a smaller thickness direction retardation even with the same composition, or a thickness direction retardation being small and mechanical. It aims at providing the manufacturing method of the polyimide precursor composition (solution composition containing a polyimide precursor) from which the polyimide excellent also in the characteristic and also excellent in transparency is obtained, and a polyimide.

The present invention relates to the following items.
1. A polyimide precursor containing a repeating unit represented by the following chemical formula (1) or a repeating unit represented by the following chemical formula (2);
Including imidazole compounds,
Content of an imidazole type compound is less than 4 mol with respect to 1 mol of repeating units of a polyimide precursor, The polyimide precursor composition characterized by the above-mentioned.

（式中、Ｘ_１は脂環構造を有する４価の基であり、Ｙ_１は芳香族環を有する２価の基であり、Ｒ_１、Ｒ_２はそれぞれ独立に水素、炭素数１〜６のアルキル基、または炭素数３〜９のアルキルシリル基である。）

(In the formula, X ₁ is a tetravalent group having an alicyclic structure, Y ₁ is a divalent group having an aromatic ring, and R ₁ and R ₂ are each independently hydrogen, C 1-6. Or an alkylsilyl group having 3 to 9 carbon atoms.)

（式中、Ｘ_２は芳香族環を有する４価の基であり、Ｙ_２は脂環構造を有する２価の基であり、Ｒ_３、Ｒ_４はそれぞれ独立に水素、炭素数１〜６のアルキル基、または炭素数３〜９のアルキルシリル基である。）

(In the formula, X ₂ is a tetravalent group having an aromatic ring, Y ₂ is a divalent group having an alicyclic structure, and R ₃ and R ₄ are each independently hydrogen, C 1-6. Or an alkylsilyl group having 3 to 9 carbon atoms.)

2. Item 2. The polyimide precursor composition according to item 1, wherein the polyimide obtained from the polyimide precursor composition has a light transmittance at a wavelength of 400 nm of a film having a thickness of 10 μm of 75% or more.
3. Item 3. The polyimide precursor composition according to item 1 or 2, wherein the content of the imidazole compound is 0.05 mol to 2 mol with respect to 1 mol of the repeating unit of the polyimide precursor.
4). Item 4. The polyimide precursor composition according to any one of Items 1 to 3, wherein the imidazole compound has a boiling point at 1 atm of less than 340 ° C.
5). Any one of Items 1 to 4, wherein the imidazole compound is any one of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, and benzimidazole. A polyimide precursor composition according to claim 1.
6). 6. A method for producing a polyimide, wherein the polyimide precursor composition according to any one of items 1 to 5 is heat-treated at a maximum heating temperature exceeding 350 ° C. to imidize the polyimide precursor.
7). The process of apply | coating the polyimide precursor composition in any one of said claim | item 1-5 on a base material,
The method for producing polyimide according to Item 6, further comprising a step of heat-treating the polyimide precursor composition on the substrate at a maximum heating temperature of 350 ° C. to imidize the polyimide precursor.
8). Item 8. The method for producing polyimide according to Item 6 or 7, wherein a maximum heating temperature of the heat treatment exceeds 400 ° C.
9. A polyimide produced by the method according to any one of Items 6 to 8.
10. Item 10. The polyimide according to Item 9, wherein the light transmittance at a wavelength of 400 nm in a film having a thickness of 10 μm is 75% or more.
11. A polyimide film produced by the method according to any one of Items 6 to 8.
12 Item 10. A substrate for display, touch panel, or solar cell, comprising the polyimide according to item 9 or 10, or the polyimide film according to item 11.

  According to the present invention, a polyimide having excellent transparency and having a small thickness direction retardation even in the same composition, or a polyimide having a small thickness direction retardation, excellent mechanical properties, and excellent transparency. The obtained polyimide precursor composition (solution composition containing a polyimide precursor) and a method for producing polyimide can be provided.

  The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is highly transparent and has a small thickness direction retardation, and has a low linear thermal expansion coefficient, facilitating the formation of fine circuits. And can be suitably used to form a substrate for display applications and the like. Moreover, the polyimide of this invention can be used suitably also in order to form the board | substrate for touch panels and a solar cell.

  The polyimide precursor composition of the present invention includes a polyimide precursor containing at least one of the repeating unit represented by the chemical formula (1) or the repeating unit represented by the chemical formula (2), and an imidazole compound. The content of the imidazole compound is less than 4 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  The polyimide obtained from the polyimide precursor containing the repeating unit represented by the chemical formula (1) or the repeating unit represented by the chemical formula (2), that is, a semi-alicyclic polyimide, has high transparency. . In the case of such a highly transparent polyimide, the use of additives that can cause coloring is not preferred. However, by adding the imidazole compound to the polyimide precursor composition at a ratio of less than 4 mol, preferably 0.05 mol or more and 2 mol or less, with respect to 1 mol of the repeating unit of the polyimide precursor, high transparency is achieved. A polyimide having a small thickness direction retardation can be obtained while keeping it. That is, according to the present invention, a polyimide having a smaller thickness direction retardation can be obtained from a polyimide precursor having the same composition while maintaining high transparency. In addition, when an imidazole compound having a boiling point of less than 340 ° C. at 1 atmosphere is used, the transparency of the resulting polyimide may be further improved.

  Furthermore, in order to obtain a highly transparent polyimide, it is generally considered that it is preferable to complete the imidization by heat-treating the polyimide precursor at a relatively low temperature. Even if the polyimide precursor is imidized by heat treatment at a temperature exceeding 350 ° C., particularly preferably exceeding 400 ° C., a highly transparent polyimide can be produced. As a result, the maximum heating temperature of the heat treatment for imidization can be set to a high temperature exceeding 350 ° C., particularly preferably a high temperature exceeding 400 ° C., so that the mechanical properties of the resulting polyimide are improved. That is, according to the present invention, a polyimide having high transparency, small thickness direction retardation, and excellent mechanical properties can be obtained.

  As above-mentioned, the polyimide precursor composition of this invention contains the polyimide precursor containing at least 1 sort (s) of the repeating unit represented by the said Chemical formula (1), or the said Chemical formula (2).

X ₁ in the chemical formula (1) is preferably a tetravalent group having an alicyclic structure having 4 to 40 carbon atoms, and Y ₁ is a divalent having an aromatic ring having 6 to 40 carbon atoms. Are preferred.

  Examples of the tetracarboxylic acid component that gives the repeating unit of the chemical formula (1) include 1,2,3,4-cyclobutanetetracarboxylic acid, isopropylidenediphenoxybisphthalic acid, cyclohexane-1,2,4,5- Tetracarboxylic acid, [1,1′-bi (cyclohexane)]-3,3 ′, 4,4′-tetracarboxylic acid, [1,1′-bi (cyclohexane)]-2,3,3 ′, 4 '-Tetracarboxylic acid, [1,1'-bi (cyclohexane)]-2,2', 3,3'-tetracarboxylic acid, 4,4'-methylenebis (cyclohexane-1,2-dicarboxylic acid), 4 , 4 ′-(propane-2,2-diyl) bis (cyclohexane-1,2-dicarboxylic acid), 4,4′-oxybis (cyclohexane-1,2-dicarboxylic acid), 4,4′-thiobis ( Chlorohexane-1,2-dicarboxylic acid), 4,4′-sulfonylbis (cyclohexane-1,2-dicarboxylic acid), 4,4 ′-(dimethylsilanediyl) bis (cyclohexane-1,2-dicarboxylic acid) 4,4 ′-(tetrafluoropropane-2,2-diyl) bis (cyclohexane-1,2-dicarboxylic acid), octahydropentalene-1,3,4,6-tetracarboxylic acid, bicyclo [2. 2.1] heptane-2,3,5,6-tetracarboxylic acid, 6- (carboxymethyl) bicyclo [2.2.1] heptane-2,3,5-tricarboxylic acid, bicyclo [2.2.2 ] Octane-2,3,5,6-tetracarboxylic acid, bicyclo [2.2.2] oct-5-ene-2,3,7,8-tetracarboxylic acid, tricyclo [4.2.2.02] , 5] Can-3,4,7,8-tetracarboxylic acid, tricyclo [4.2.2.02,5] dec-7-ene-3,4,9,10-tetracarboxylic acid, 9-oxatricyclo [ 4.2.1.02,5] nonane-3,4,7,8-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane 5,5 ′ ', 6,6' '-tetracarboxylic acid, (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethananaphthalene-2c, 3c, 6c, 7c-tetracarboxylic acid, (4arH, 8acH)- Decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acid, tetracarboxylic dianhydrides, tetracarboxylic acid silyl esters, tetracarboxylic acid esters Ether, and derivatives of such tetracarboxylic acid chloride. A tetracarboxylic acid component may be used independently and can also be used in combination of multiple types.

  Examples of the diamine component that gives the repeating unit of the chemical formula (1) include p-phenylenediamine, m-phenylenediamine, benzidine, 3,3′-diamino-biphenyl, and 2,2′-bis (trifluoromethyl) benzidine. 3,3′-bis (trifluoromethyl) benzidine, m-tolidine, 4,4′-diaminobenzanilide, 3,4′-diaminobenzanilide, N, N′-bis (4-aminophenyl) terephthalamide N, N′-p-phenylenebis (p-aminobenzamide), 4-aminophenoxy-4-diaminobenzoate, bis (4-aminophenyl) terephthalate, bis (4-amino) biphenyl-4,4′-dicarboxylate Phenyl) ester, p-phenylenebis (p-aminobenzoate), bis (4-amino) Nophenyl)-[1,1′-biphenyl] -4,4′-dicarboxylate, [1,1′-biphenyl] -4,4′-diyl bis (4-aminobenzoate), 4,4′-oxy Dianiline, 3,4'-oxydianiline, 3,3'-oxydianiline, p-methylenebis (phenylenediamine), 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3- Aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 2,2- Bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, bis (4-aminophenyl) sulfone, 3,3′-bis (tri Fluoromethyl) benzidine, 3,3′-bis ((aminophenoxy) phenyl) propane, 2,2′-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (4- (4-aminophenoxy) diphenyl ) Sulfone, bis (4- (3-aminophenoxy) diphenyl) sulfone, octafluorobenzidine, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diaminobiphenyl 3,3′-difluoro-4,4′-diaminobiphenyl, 2 sulfone sulfone, 4-bis (4-aminoanilino) -6-amino-1,3,5-triazine, 2,4-bis (4-aminoanilino) ) -6-methylamino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-ethylamino-1 3,5-triazine, 2,4-bis (4-aminoanilino) -6-anilino-1,3,5-triazine. A diamine component may be used independently and can also be used in combination of multiple types.

  The polyimide precursor containing at least one type of repeating unit represented by the chemical formula (1) may contain other repeating units other than the repeating unit represented by the chemical formula (1). The tetracarboxylic acid component and diamine component that give other repeating units are not particularly limited, and any other known aromatic or aliphatic tetracarboxylic acids or known aromatic or aliphatic diamines can be used. . Other tetracarboxylic acid components may be used alone or in combination of two or more. Other diamine components may be used alone or in combination of two or more.

  The content of other repeating units other than the repeating unit represented by the chemical formula (1) is preferably 30 mol% or less or less than 30 mol%, more preferably 20 mol% or less, based on all repeating units. More preferably, it is 10 mol% or less.

X ₂ in the chemical formula (2) is preferably a tetravalent group having an aromatic ring having 6 to 40 carbon atoms, and Y ₂ is a divalent having an alicyclic structure having 4 to 40 carbon atoms. Are preferred.

  Examples of the tetracarboxylic acid component that gives the repeating unit of the chemical formula (2) include 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane and 4- (2,5-dioxotetrahydrofuran-3- Yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid, pyromellitic acid, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid, 3,3 ′, 4,4′- Biphenyltetracarboxylic acid, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 4,4′-oxydiphthalic acid, bis (3,4-dicarboxyphenyl) sulfone dianhydride, m-terphenyl-3, 4,3 ′, 4′-tetracarboxylic dianhydride, p-terphenyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, biscarboxyphenyldimethylsilane Emissions, bis-dicarboxyphenoxy diphenyl sulfide, or sulfonyl di phthalate, these tetracarboxylic dianhydrides, tetracarboxylic acid silyl ester, tetracarboxylic acid esters, derivatives of such tetracarboxylic acid chloride. A tetracarboxylic acid component may be used independently and can also be used in combination of multiple types.

  Examples of the diamine component that gives the repeating unit of the chemical formula (2) include 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1, 4-diamino-2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4- Diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,3-diaminocyclobutane, 1,4-bis (aminomethyl) cyclohexane, 1 , 3-bis (aminomethyl) cyclohexane, diaminobicycloheptane, diamy Nomethylbicycloheptane, diaminooxybicycloheptane, diaminomethyloxybicycloheptane, isophoronediamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis (aminocyclohexyl) methane, bis (aminocyclohexyl) isopropylidene 6,6 ′ -Bis (3-aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, 6,6′-bis (4-aminophenoxy) -3,3,3 ′, 3 And '-tetramethyl-1,1'-spirobiindane. A diamine component may be used independently and can also be used in combination of multiple types.

  The polyimide precursor containing at least one repeating unit represented by the chemical formula (2) can contain other repeating units other than the repeating unit represented by the chemical formula (2). The tetracarboxylic acid component and diamine component that give other repeating units are not particularly limited, and any other known aromatic or aliphatic tetracarboxylic acids or known aromatic or aliphatic diamines can be used. . Other tetracarboxylic acid components may be used alone or in combination of two or more. Other diamine components may be used alone or in combination of two or more.

  The content of other repeating units other than the repeating unit represented by the chemical formula (2) is preferably 30 mol% or less or less than 30 mol%, more preferably 20 mol% or less, based on all repeating units. More preferably, it is 10 mol% or less.

  The polyimide precursor may include at least one repeating unit represented by the chemical formula (1) and at least one repeating unit represented by the chemical formula (2). Also in that case, the content of other repeating units other than the repeating units represented by the chemical formulas (1) and (2) is preferably 30 mol% or less or less than 30 mol% with respect to all repeating units. More preferably, it is 20 mol% or less, More preferably, it is 10 mol% or less.

  In a certain embodiment, as a polyimide precursor, the polyimide precursor containing the repeating unit represented by the following chemical formula (1-1) is preferable, for example, The following chemical formula (1-2) and the following chemical formula (1-3) The total content of the repeating units represented by the chemical formula (1-2) and the chemical formula (1-3) is 80 mol% or more with respect to all the repeating units. A polyimide precursor is more preferable.

（式中、Ａは芳香族環を有する２価の基であり、Ｒ_１、Ｒ_２はそれぞれ独立に水素、炭素数１〜６のアルキル基、または炭素数３〜９のアルキルシリル基である。）

(In the formula, A is a divalent group having an aromatic ring, and R ₁ and R ₂ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms. .)

（式中、Ａは芳香族環を有する２価の基であり、Ｒ_１、Ｒ_２はそれぞれ独立に水素、炭素数１〜６のアルキル基、または炭素数３〜９のアルキルシリル基である。）

(In the formula, A is a divalent group having an aromatic ring, and R ₁ and R ₂ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms. .)

（式中、Ａは芳香族環を有する２価の基であり、Ｒ_１、Ｒ_２はそれぞれ独立に水素、炭素数１〜６のアルキル基、または炭素数３〜９のアルキルシリル基である。）

(In the formula, A is a divalent group having an aromatic ring, and R ₁ and R ₂ are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms. .)

However, the chemical formula (1-1), the chemical formula (1-2), and the chemical formula (1-3) are either the 5-position or the 6-position of two norbornane rings (bicyclo [2.2.1] heptane). A group represented by —COOR ₁ or a group represented by —COOR _{2 in} which _one of the acid groups is reacted with an amino group to form an amide bond (—CONH—), and one of the acid groups does not form an amide bond. Indicates that That is, the chemical formula (1-1), the chemical formula (1-2), and the chemical formula (1-3) include four structural isomers, that is, (i) a group represented by -COOR ₁ at the 5-position. A group represented by -CONH- at the 6-position, a group represented by -COOR ₂ at the 5 ''-position, and a group represented by -CONH-A- at the 6 ''-position, (Ii) a group represented by -COOR ₁ at the 6-position, a group represented by -CONH- at the 5-position, and a group represented by -COOR ₂ at the 5 ''-position, Having a group represented by -CONH-A-, (iii) a group represented by -COOR ₁ at the 5-position, a group represented by -CONH- at the 6-position, and the 6 ''-position A group represented by —COOR ₂ having a group represented by —CONH—A— at the 5 ″ position, and (iv) a group represented by —COOR ₁ at the 6 position— CONH- And a group represented by —COOR ₂ at the 6 ″ position and a group represented by —CONH-A— at the 5 ″ position are included.

  Further, the polyimide precursor is a repeating unit represented by the chemical formula (1-1) in which A is a group represented by the following chemical formula (1-A), more preferably A is represented by the following chemical formula (1-A). It is preferable that at least one repeating unit represented by the chemical formula (1-2) and / or the chemical formula (1-3) which is a group to be included is included.

（式中、ｍは０〜３の整数を、ｎは０〜３の整数をそれぞれ独立に示す。Ｖ、Ｕ、Ｔはそれぞれ独立に水素原子、メチル基、トリフルオロメチル基よりなる群から選択される１種を示し、Ｚ、Ｗはそれぞれ独立に直接結合、または 式：−ＮＨＣＯ-、−ＣＯＮＨ-、−ＣＯＯ-、−ＯＣＯ-で表される基よりなる群から選択される１種を示す。）

(In the formula, m represents an integer of 0 to 3, and n represents an integer of 0 to 3 independently. V, U, and T are each independently selected from the group consisting of a hydrogen atom, a methyl group, and a trifluoromethyl group. Z and W are each independently a direct bond, or one selected from the group consisting of groups represented by the formula: —NHCO—, —CONH—, —COO—, —OCO—. Show.)

  In other words, in some embodiments, the polyimide precursor is norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″- Tetracarboxylic acids and the like, more preferably trans-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetra Carboxylic acids etc. and / or cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acids (Tetracarboxylic acids, etc. are tetracarboxylic acids, tetracarboxylic dianhydrides, tetracarboxylic acid silyl esters, tetracarboxylic acid esters, tetracarboxylic acids, etc. A tetracarboxylic acid component containing a tetracarboxylic acid derivative such as a boronic acid chloride) and a diamine component having an aromatic ring, more preferably a chemical formula (1) wherein A is a group represented by the chemical formula (1-A) -1), a polyimide precursor obtained from a diamine component containing a diamine component that gives a repeating unit of chemical formula (1-2) or chemical formula (1-3).

  Examples of the tetracarboxylic acid component that gives the repeating unit of the chemical formula (1-1) include norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6, One kind such as 6 ″ -tetracarboxylic acids may be used alone, or a plurality of kinds may be used in combination. Examples of the tetracarboxylic acid component that gives the repeating unit of the chemical formula (1-2) include trans-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5. One type such as 5 ″, 6,6 ″ -tetracarboxylic acid may be used alone, or a plurality of types may be used in combination. Examples of the tetracarboxylic acid component that gives the repeating unit of the chemical formula (1-3) include cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5. One type such as 5 ″, 6,6 ″ -tetracarboxylic acid may be used alone, or a plurality of types may be used in combination.

  In a more preferable form of the polyimide precursor, a tetracarboxylic acid component (trans-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-) that gives the repeating unit of the chemical formula (1-2) is used. One or more of spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acids, etc.) may be used, and the tetra unit giving the repeating unit of the above chemical formula (1-3) Carboxylic acid component (cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acids, etc.) Or a tetracarboxylic acid component (trans-endo-endo-norbol) that gives a repeating unit of the chemical formula (1-2). One or more of N-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid, etc.) and the above chemical formula (1 -3) a tetracarboxylic acid component (cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6 One or more of 6 ″ -tetracarboxylic acids and the like) may be used.

  The polyimide precursor preferably has a total content of repeating units represented by the chemical formula (1-2) and the chemical formula (1-3) of 80 mol% or more with respect to all repeating units. In addition, at least one type of repeating unit represented by the chemical formula (1-2) and the chemical formula (1-3) is included, and the total number of the repeating units is preferably 80 mol% or more in all repeating units. Is preferably 90 mol% or more, more preferably 95 mol% or more, particularly preferably 99 mol% or more. By including at least one type of repeating unit represented by the chemical formula (1-2) and the chemical formula (1-3), and including the repeating unit in all repeating units in total, preferably 80 mol% or more, The resulting linear thermal expansion coefficient of the polyimide is reduced.

  The diamine component that gives the repeating unit of the chemical formula (1-1), the chemical formula (1-2), or the chemical formula (1-3) is one in which A is a group represented by the chemical formula (1-A). It is preferred to include a diamine that provides

  The diamine component that gives the repeating unit of the chemical formula (1-1), the chemical formula (1-2), or the chemical formula (1-3) in which A is the structure of the chemical formula (1-A) has an aromatic ring, When there are a plurality of rings, the aromatic rings are each independently linked by a direct bond, an amide bond, or an ester bond. The connection position of the aromatic rings is not particularly limited, but it may form a linear structure by bonding at the 4-position to the amino group or the connection group of the aromatic rings, and the resulting polyimide may have low linear thermal expansion. . In addition, a methyl group or a trifluoromethyl group may be substituted on the aromatic ring. The substitution position is not particularly limited.

  The diamine component that gives the repeating unit of the chemical formula (1-1), the chemical formula (1-2), or the chemical formula (1-3) in which A is the structure of the chemical formula (1-A) is not particularly limited. Are, for example, p-phenylenediamine, m-phenylenediamine, benzidine, 3,3′-diamino-biphenyl, 2,2′-bis (trifluoromethyl) benzidine, 3,3′-bis (trifluoromethyl) benzidine , M-tolidine, 4,4′-diaminobenzanilide, 3,4′-diaminobenzanilide, N, N′-bis (4-aminophenyl) terephthalamide, N, N′-p-phenylenebis (p- Aminobenzamide), 4-aminophenoxy-4-diaminobenzoate, bis (4-aminophenyl) terephthalate, biphenyl-4,4′- Carboxylic acid bis (4-aminophenyl) ester, p-phenylenebis (p-aminobenzoate), bis (4-aminophenyl)-[1,1′-biphenyl] -4,4′-dicarboxylate, [1 , 1′-biphenyl] -4,4′-diylbis (4-aminobenzoate) and the like, and may be used alone or in combination of two or more. Among these, p-phenylenediamine, m-tolidine, 4,4′-diaminobenzanilide, 4-aminophenoxy-4-diaminobenzoate, 2,2′-bis (trifluoromethyl) benzidine, benzidine, N, N '-Bis (4-aminophenyl) terephthalamide, biphenyl-4,4'-dicarboxylic acid bis (4-aminophenyl) ester is preferred, p-phenylenediamine, 4,4'-diaminobenzanilide, 2,2' -Bis (trifluoromethyl) benzidine is more preferred. By using p-phenylenediamine, 4,4′-diaminobenzanilide, and 2,2′-bis (trifluoromethyl) benzidine as the diamine component, the resulting polyimide has both high heat resistance and high transmittance. . These diamines may be used alone or in combination of two or more. Note that o-tolidine is not preferred because of its high risk.

  As the diamine component that gives the repeating unit of the chemical formula (1-1), the chemical formula (1-2), or the chemical formula (1-3), A is a diamine that gives the structure of the chemical formula (1-A). Other diamines other than the components can be used in combination. Other aromatic or aliphatic diamines can be used as other diamine components. Other diamine components include, for example, 4,4′-oxydianiline, 3,4′-oxydianiline, 3,3′-oxydianiline, bis (4-aminophenyl) sulfide, p-methylenebis (phenylenediamine) ), 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- ( 4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, bis (4-aminophenyl) sulfone, 3,3-bis ((aminophenoxy) phenyl) propane, 2 , 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (4- (4-aminophenoxy) diph Enyl) sulfone, bis (4- (3-aminophenoxy) diphenyl) sulfone, octafluorobenzidine, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diamino Biphenyl, 3,3′-difluoro-4,4′-diaminobiphenyl, 9,9-bis (4-aminophenyl) fluorene, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propyl Cyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,4- Diaminocyclohexane, 1,3-diaminocyclobutane, 1,4-bis (aminomethyl) cyclohexane, 1,3-bis (aminomethyl) cyclohexane, diaminobicycloheptane, diaminomethylbicycloheptane, diaminooxybicycloheptane, diaminomethyl Oxybicycloheptane, isophoronediamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis (aminocyclohexyl) methane, bis (aminocyclohexyl) isopropylidene 6,6′-bis (3-aminophenoxy) -3,3 , 3 ', 3'-te Lamethyl-1,1′-spirobiindane, 6,6′-bis (4-aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, and their derivatives, You may use individually and can also be used in combination of multiple types.

  In the polyimide precursor of the present invention, A is at least one repeating unit of the chemical formula (1-1) in which A is represented by the chemical formula (1-A), more preferably, A is the chemical formula (1- At least one repeating unit represented by the chemical formula (1-2) represented by A) and / or A represented by the chemical formula (1-A) is represented by the chemical formula (1-3). It is preferable to include at least one repeating unit. In other words, the diamine component that gives the repeating unit of the chemical formula (1-1), more preferably the repeating unit of the chemical formula (1-2) and the chemical formula (1-3), is represented by A being the chemical formula (1-A). It is preferable to include a diamine component that gives a structure of The repeating unit of the chemical formula (1-1), more preferably the diamine component giving A in the chemical formula (1-2) and the chemical formula (1-3) gives the structure of the chemical formula (1-A). By being a diamine component, the heat resistance of the resulting polyimide is improved.

  In the polyimide precursor of the present invention, the chemical formula (1-1) or 100 mol% of the diamine component giving A in the chemical formula (1-2) and the chemical formula (1-3) has the chemical formula (1-A). The ratio of the diamine components that give the structure is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 100 mol%. % Is preferred. In other words, the chemical formula (1-1) in which A is the structure of the chemical formula (1-A), or the ratio of one or more repeating units of the chemical formula (1-2) and the chemical formula (1-3) Are, in total, preferably 50 mol% or more, more preferably 70 mol in all repeating units represented by the chemical formula (1-1) or the chemical formula (1-2) and the chemical formula (1-3). % Or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, particularly preferably 100 mol%. When the ratio of the diamine component giving the structure of the chemical formula (1-A) is smaller than 50 mol%, the linear thermal expansion coefficient of the resulting polyimide may increase. In one embodiment, from the viewpoint of mechanical properties of the obtained polyimide, 100 mol of the diamine component that gives A in the chemical formula (1-1) or the chemical formula (1-2) and the chemical formula (1-3). %, The ratio of the diamine components giving the structure of the chemical formula (1-A) is preferably 80 mol% or less, more preferably 90 mol% or less or less than 90 mol% in total. . For example, other aromatic or aliphatic diamines such as 4,4′-oxydianiline are substituted with the chemical formula (1-1) or the repeating units of the chemical formula (1-2) and the chemical formula (1-3). In 100 mol% of the diamine component that gives the above, preferably less than 20 mol%, more preferably 10 mol% or less, more preferably less than 10 mol%.

  In a certain embodiment, the polyimide precursor containing the repeating unit represented by the chemical formula (1-1) of the present invention has a chemical formula (1-1) in which A is represented by the chemical formula (1-A). It may be preferred to include at least two types of repeating units. In a certain embodiment, the polyimide precursor containing the repeating unit represented by the chemical formula (1-2) and / or the repeating unit represented by the chemical formula (1-3) of the present invention is such that A is represented by the chemical formula ( It may be preferable to include at least two repeating units represented by the chemical formula (1-2) or the chemical formula (1-2) represented by 1-A). In other words, the diamine component that gives the repeating unit of the chemical formula (1-1), or the diamine component that gives the repeating unit of the chemical formula (1-2) and the chemical formula (1-3), the A represents the chemical formula ( It may be preferred to include at least two diamine components that give what is the structure of 1-A). A diamine in which the diamine component giving A in the chemical formula (1-1) or A in the chemical formula (1-2) and the chemical formula (1-3) gives a structure of the chemical formula (1-A) By containing at least two kinds of components, the obtained polyimide can be balanced between high transparency and low linear thermal expansion (that is, a polyimide having high transparency and low linear thermal expansion coefficient can be obtained).

  The polyimide precursor of the present invention may contain at least two repeating units of the chemical formula (1-2) in which A has the structure of the chemical formula (1-A). It may contain at least two types of repeating units of the chemical formula (1-3) having the structure of the chemical formula (1-A), and the chemical formula (A) is a structure of the chemical formula (1-A). It may include at least one repeating unit of 1-2) and at least one repeating unit of the chemical formula (1-3) in which A has the structure of the chemical formula (1-A).

In some embodiments, the polyimide precursor of the present invention comprises:
(I) A is m and / or n is 1 to 3, and Z and / or W are each independently any of —NHCO—, —CONH—, —COO—, or —OCO—. The chemical formula (1-1) having the structure of the chemical formula (1-A), preferably containing at least one repeating unit (I) of the chemical formula (1-2) and the chemical formula (1-3),
(Ii) A is the structure of the chemical formula (1-A) in which m and n are 0, or the chemical formula in which m and / or n is 1 to 3, and Z and W are direct bonds. It is more preferable that the chemical formula (1-1) having the structure of (1-A), preferably including at least one repeating unit (II) of the chemical formula (1-2) and the chemical formula (1-3). There is.

  In this embodiment, as the repeating unit (I), for example, the repeating unit represented by the chemical formula (1-1) in which A is represented by any one of the following chemical formulas (D-1) to (D-3) The unit is preferable, and the repeating unit of the chemical formula (1-1), in which A is represented by any one of the following chemical formulas (D-1) to (D-2), is more preferable. In addition, the diamine component which gives the repeating unit of the said Chemical formula (1-1) whose A is represented by the following chemical formula (D-1) or the following chemical formula (D-2) is 4,4'- diaminobenzanilide. Yes, the diamine component that gives the repeating unit of the chemical formula (1-1) in which A is represented by the following chemical formula (D-3) is bis (4-aminophenyl) terephthalate, and these diamines are used alone. It can also be used in combination, or multiple types can be used in combination.

  In this embodiment, as the repeating unit (II), for example, the repeating unit represented by the chemical formula (1-1) in which A is represented by any one of the following chemical formulas (D-4) to (D-6) The unit is preferable, and the repeating unit of the chemical formula (1-1), in which A is represented by any one of the following chemical formulas (D-4) to (D-5), is more preferable. In addition, the diamine component which gives the repeating unit of the said Chemical formula (1-1) whose A is what is represented by following Chemical formula (D-4) is p-phenylenediamine, A is following Chemical formula (D-5). The diamine component that gives the repeating unit of the chemical formula (1-1) is 2,2′-bis (trifluoromethyl) benzidine, and A is represented by the following chemical formula (D-6) The diamine component that gives the repeating unit of the chemical formula (1-1) is m-tolidine, and these diamines may be used alone or in combination of two or more.

  In the polyimide precursor of this embodiment, the ratio of one or more of the repeating units (I) is 30 mol% or more and 70 mol% or less in total in all repeating units represented by the chemical formula (1-1). And the ratio of one or more repeating units (II) is preferably 30 mol% or more and 70 mol% or less in the total repeating units represented by the chemical formula (1-1). The ratio of one or more units (I) is 40 mol% or more and 60 mol% or less in the total repeating units represented by the chemical formula (1-1), and one or more repeating units (II). Is preferably 40 mol% or more and 60 mol% or less in all repeating units represented by the chemical formula (1-1). In a certain embodiment, it is more preferable that the ratio of the said repeating unit (I) is less than 60 mol% in all the repeating units represented by the said Chemical formula (1-1), and is 50 mol% or less in total. It is more preferable that it is 40 mol% or less. In one embodiment, other than the repeating unit (I) and the repeating unit (II), other repeating units represented by the chemical formula (1-1) (for example, A has a plurality of aromatic rings). And those in which aromatic rings are connected by an ether bond (—O—)) in all repeating units represented by the chemical formula (1-1), preferably less than 20 mol%, more preferably 10 mol. %, Particularly preferably less than 10 mol% may be preferred. Furthermore, in a certain embodiment, the ratio of 1 or more types of said repeating unit (I) is 20 mol% or more and 80 mol% or less in all the repeating units represented by the said Chemical formula (1-1) in total. The ratio of one or more of the repeating units (II) may be preferably 20 mol% or more and 80 mol% or less in total in all repeating units represented by the chemical formula (1-1).

  In one embodiment, the polyimide precursor containing the chemical formula (1-1) of the present invention, or the repeating unit of the chemical formula (1-2) and / or the chemical formula (1-3) is represented by the chemical formula (1- 1), or a diamine component that gives A in the chemical formula (1-2) and the chemical formula (1-3) (repeating unit of the chemical formula (1-1), or the chemical formula (1-2) and the chemical formula ( The diamine component that gives the repeating unit of 1-3) includes at least two kinds of diamine components that give the structure of the chemical formula (1-A), and one of them is 4,4′-diaminobenzanilide. preferable. In the chemical formula (1-1), or in the chemical formula (1-2) and the chemical formula (1-3), the diamine component that gives A includes at least two kinds of diamine components that give the structure of the chemical formula (1-A). In addition, when one of them is 4,4′-diaminobenzanilide, a polyimide having high heat resistance in addition to high transparency and low linear thermal expansion can be obtained.

  In one embodiment, the polyimide precursor containing the chemical formula (1-1) of the present invention, or the repeating unit of the chemical formula (1-2) and / or the chemical formula (1-3) is represented by the chemical formula (1- 1), or a diamine component that gives A in the chemical formula (1-2) and the chemical formula (1-3) (repeating unit of the chemical formula (1-1), or the chemical formula (1-2) and the chemical formula ( 1-3) the diamine component giving the repeating unit) contains at least one selected from 2,2′-bis (trifluoromethyl) benzidine and p-phenylenediamine and 4,4′-diaminobenzanilide. Is particularly preferred. By combining these diamine components, a polyimide having both high transparency, low linear thermal expansion and heat resistance can be obtained.

  In this embodiment, the chemical formula (1-1), or a diamine component that gives A in the chemical formula (1-2) and the chemical formula (1-3) (the repeating unit of the chemical formula (1-1), or The diamine component that gives the repeating unit of the chemical formula (1-2) and the chemical formula (1-3) preferably contains 4,4′-diaminobenzanilide in an amount of 20 mol% or more and 80 mol% or less, and , P-phenylenediamine and 2,2′-bis (trifluoromethyl) benzidine or both are preferably contained in an amount of 20 mol% to 80 mol%, more preferably 4,4′-diamino. Benzanilide is contained in an amount of 30 mol% or more and 70 mol% or less, and either p-phenylenediamine or 2,2′-bis (trifluoromethyl) benzidine. Or both, and preferably 30 mol% or more and 70 mol% or less, particularly preferably 4,4′-diaminobenzanilide is contained 40 mol% or more and 60 mol% or less, and p-phenylenediamine More preferably, it is contained in 40 mol% or more and 60 mol% or less of either or both of 2,2′-bis (trifluoromethyl) benzidine. As the diamine component that gives A in the chemical formula (1-1) or the chemical formula (1-2) and the chemical formula (1-3), 4,4′-diaminobenzanilide is 30 mol% or more and 70 mol%. High transparency and low by including in 30 mol% or more and 70 mol% or less in one or both of p-phenylenediamine and 2,2′-bis (trifluoromethyl) benzidine. A polyimide having both linear thermal expansion and heat resistance is obtained. In one embodiment, the chemical formula (1-1), or a diamine component that gives A in the chemical formula (1-2) and the chemical formula (1-3) (the repeating unit of the chemical formula (1-1), or As the diamine component that gives the repeating unit of the chemical formula (1-2) and the chemical formula (1-3), it is more preferable to contain 4,4′-diaminobenzanilide in an amount of less than 60 mol%, and 50 mol% or less. It is more preferable that it is contained at 40 mol% or less.

  The polyimide precursor of this invention can contain other repeating units other than the repeating unit represented by the said Chemical formula (1-1) or the said Chemical formula (1-2) and the said Chemical formula (1-3). .

  Other aromatic or aliphatic tetracarboxylic acids can be used as the tetracarboxylic acid component that provides other repeating units. For example, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2 -Dicarboxylic acid, pyromellitic acid, 3,3 ', 4,4'-benzophenone tetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 2,3,3 ', 4'-biphenyltetra Carboxylic acid, 4,4'-oxydiphthalic acid, bis (3,4-dicarboxyphenyl) sulfone dianhydride, m-terphenyl-3,4,3 ', 4'-tetracarboxylic dianhydride, p- Terphenyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, biscarboxyphenyldimethylsilane, bisdicarboxyphenoxydiphenyl sulfide, sulfonyldiph Formic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, isopropylidenediphenoxybisphthalic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, [1,1′-bi (cyclohexane)]- 3,3 ′, 4,4′-tetracarboxylic acid, [1,1′-bi (cyclohexane)]-2,3,3 ′, 4′-tetracarboxylic acid, [1,1′-bi (cyclohexane) ] -2,2 ′, 3,3′-tetracarboxylic acid, 4,4′-methylenebis (cyclohexane-1,2-dicarboxylic acid), 4,4 ′-(propane-2,2-diyl) bis (cyclohexane) -1,2-dicarboxylic acid), 4,4′-oxybis (cyclohexane-1,2-dicarboxylic acid), 4,4′-thiobis (cyclohexane-1,2-dicarboxylic acid), 4,4′-sulfonylbis (Sh (Rohexane-1,2-dicarboxylic acid), 4,4 ′-(dimethylsilanediyl) bis (cyclohexane-1,2-dicarboxylic acid), 4,4 ′-(tetrafluoropropane-2,2-diyl) bis ( Cyclohexane-1,2-dicarboxylic acid), octahydropentalene-1,3,4,6-tetracarboxylic acid, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid, 6 -(Carboxymethyl) bicyclo [2.2.1] heptane-2,3,5-tricarboxylic acid, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, bicyclo [2. 2.2] oct-5-ene-2,3,7,8-tetracarboxylic acid, tricyclo [4.2.2.02,5] decane-3,4,7,8-tetracarboxylic acid, tricyclo [ 4.2.2.02 , 5] dec-7-ene-3,4,9,10-tetracarboxylic acid, 9-oxatricyclo [4.2.1.02,5] nonane-3,4,7,8-tetracarboxylic acid (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethananaphthalene-2c, 3c, 6c, 7c-tetracarboxylic acid, (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-di Derivatives such as methanonaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acid, and acid dianhydrides thereof may be used, and may be used alone or in combination of two or more. Among these, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, ( 4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene-2c, 3c, 6c, 7c-tetracarboxylic acid, (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene Derivatives such as -2t, 3t, 6c, 7c-tetracarboxylic acid, and these acid dianhydrides are more preferable because polyimide is easy to produce and the resulting polyimide has excellent heat resistance. These acid dianhydrides may be used alone or in combination of two or more.

  Moreover, in the case of the polyimide precursor containing the repeating unit of the chemical formula (1-2) and / or the chemical formula (1-3), cis-endo-endo-norbornane- is used as a tetracarboxylic acid component that gives other repeating units. 2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acids and the like, and trans-endo-endo-norbornane-2-spiro Other α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acids and the like other norbornane-2-spiro-α-cyclopentanone -Α'-spiro-2 "-norbornane-5,5", 6,6 "-tetracarboxylic acids and the like (for example, norbornane-2-spiro-α-cyclopenta Emissions -α'- spiro-2 '' - norbornane-5,5 ', 6,6' '- it is also possible to use four kinds of stereoisomers of tetracarboxylic dianhydride).

  The diamine component that gives other repeating units may be a diamine component that gives the structure of the chemical formula (1-A). In other words, as a diamine component that gives another repeating unit, A is a repeating unit of the chemical formula (1-1) having the structure of the chemical formula (1-A), or A is a structure of the chemical formula (1-A). The diamine illustrated as a diamine component which gives the repeating unit of the said Chemical formula (1-2) and the said Chemical formula (1-3) which is can be used. These diamines may be used alone or in combination of two or more.

  Other aromatic or aliphatic diamines can be used as the diamine component giving other repeating units. For example, 4,4′-oxydianiline, 3,4′-oxydianiline, 3,3′-oxydianiline, bis (4-aminophenyl) sulfide, p-methylenebis (phenylenediamine), 1,3- Bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl ] Hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, bis (4-aminophenyl) sulfone, 3,3-bis ((aminophenoxy) phenyl) propane, 2,2-bis (3 -Amino-4-hydroxyphenyl) hexafluoropropane, bis (4- (4-aminophenoxy) diphenyl) sulfone, bis ( 4- (3-aminophenoxy) diphenyl) sulfone, octafluorobenzidine, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diaminobiphenyl, 3,3 ′ -Difluoro-4,4'-diaminobiphenyl, 9,9-bis (4-aminophenyl) fluorene, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) Biphenyl, 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylcyclohexane, 1,4- Diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2- Sobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, 1, 3-diaminocyclobutane, 1,4-bis (aminomethyl) cyclohexane, 1,3-bis (aminomethyl) cyclohexane, diaminobicycloheptane, diaminomethylbicycloheptane, diaminooxybicycloheptane, diaminomethyloxybicycloheptane, isophoronediamine, Diaminotricyclodecane, diaminomethyltricyclodecane, bis (aminocyclohexyl) methane, bis (aminocyclohexyl) isopropylidene 6,6′-bis (3-aminophenoxy) -3,3,3 ′, 3′- Tetramethyl-1,1'-spirobi And nandane, 6,6′-bis (4-aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, etc. and their derivatives may be used alone. Moreover, it can also be used in combination of multiple types.

  The method for synthesizing norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acids and the like is not particularly limited. Can be synthesized by the method described in Patent Document 8. As described in Non-Patent Document 1, some stereoisomers may be included depending on the synthesis method. Norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid or the like, or its intermediate is purified with a column etc. By doing so, the stereoisomers can be separated individually or several mixtures can be fractionated.

  trans-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acids and the like, and cis-endo -Endo-norbornane-2-spiro- [alpha] -cyclopentanone- [alpha] '-spiro-2 "-norbornane-5,5", 6,6 "-tetracarboxylic acids or the like alone or a mixture thereof As for norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid or the like, or an intermediate thereof as a column It can be obtained by purifying with the above.

  When the tetracarboxylic acid component and the diamine component contain isomers, the isomers may be isolated and used for polymerization or the like, or the isomers may be used in polymerization or the like as a mixture.

In the polyimide precursor of the present invention, R ₁ and R _{2 in} the chemical formula (1) and R ₃ and R _{4 in} the chemical formula (2) are each independently hydrogen, 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. Or an alkylsilyl group having 3 to 9 carbon atoms. R ₁ and R ₂ , R ₃ and R ₄ can change the type of functional group and the introduction rate of the functional group by the production method described later.

When R ₁ and R ₂ , R ₃ and R ₄ are hydrogen, polyimide tends to be easily produced.

Further, _{R 1} and _R 2, _{R 3} and _{R 4} having 1 to 6 carbon atoms, preferably when an alkyl group having 1 to 3 carbon atoms, tend to excellent storage stability of the polyimide precursor. In this case, R ₁ and R ₂ , R ₃ and R ₄ are more preferably a methyl group or an ethyl group.

Furthermore, when R ₁ and R ₂ , R ₃ and R ₄ are an alkylsilyl group having 3 to 9 carbon atoms, the solubility of the polyimide precursor tends to be excellent. In this case, R ₁ and R ₂ , R ₃ and R ₄ are more preferably a trimethylsilyl group or a t-butyldimethylsilyl group.

The introduction rate of the functional group is not particularly limited, but when introducing an alkyl group or an alkylsilyl group, R ₁ and R ₂ , R ₃ and R ₄ are each 25% or more, preferably 50% or more, more preferably More than 75% can be an alkyl group or an alkylsilyl group.

Polyimide precursors of the present invention, the chemical _{structure R 1} and _R 2, _{R 3} and _{R 4} take, 1) a polyamic acid _{(R 1} and _R 2, _{R 3} and _{R 4} is hydrogen), 2) a polyamic acid ester (At least part of R ₁ and R ₂ , R ₃ and R ₄ is an alkyl group), 3) 4) Polyamic acid silyl ester (R ₁ and R ₂ , R ₃ and R ₄ are at least part of an alkylsilyl group) Can be classified. And the polyimide precursor of this invention can be easily manufactured with the following manufacturing methods for every classification. However, the manufacturing method of the polyimide precursor of this invention is not limited to the following manufacturing methods.

1) Polyamic acid The polyimide precursor of the present invention comprises a tetracarboxylic dianhydride as a tetracarboxylic acid component and a diamine component in a solvent in an approximately equimolar amount, preferably a molar ratio of the diamine component to the tetracarboxylic acid component [diamine. The number of moles of component / number of moles of tetracarboxylic acid component] is preferably 0.90 to 1.10, more preferably 0.95 to 1.05, for example, imidization at a relatively low temperature of 120 ° C. or less. It can obtain suitably as a polyimide precursor solution composition by reacting, suppressing.

  Although it does not limit, more specifically, diamine is melt | dissolved in an organic solvent, Tetracarboxylic dianhydride is added gradually, stirring to this solution, 0-120 degreeC, Preferably it is 5-80. A polyimide precursor is obtained by stirring for 1 to 72 hours in the range of ° C. When the reaction is carried out at 80 ° C. or higher, the molecular weight varies depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be produced stably. The order of addition of diamine and tetracarboxylic dianhydride in the above production method is preferable because the molecular weight of the polyimide precursor is likely to increase. Moreover, it is also possible to reverse the order of addition of the diamine and tetracarboxylic dianhydride in the above production method, and this is preferable because precipitates are reduced.

  Moreover, when the molar ratio of the tetracarboxylic acid component and the diamine component is an excess of the diamine component, if necessary, an amount of a carboxylic acid derivative substantially corresponding to the excess mole number of the diamine component is added, and the tetracarboxylic acid component and the diamine are added. The molar ratio of the components can be approximated to the equivalent. As the carboxylic acid derivative herein, a tetracarboxylic acid that does not substantially increase the viscosity of the polyimide precursor solution, that is, substantially does not participate in molecular chain extension, or a tricarboxylic acid that functions as a terminal terminator and its anhydride, Dicarboxylic acid and its anhydride are preferred.

2) Polyamic acid ester After reacting tetracarboxylic dianhydride with an arbitrary alcohol to obtain a diester dicarboxylic acid, it is reacted with a chlorinating reagent (thionyl chloride, oxalyl chloride, etc.) to obtain a diester dicarboxylic acid chloride. The polyimide precursor is obtained by stirring the diester dicarboxylic acid chloride and the diamine in the range of -20 to 120 ° C, preferably -5 to 80 ° C for 1 to 72 hours. When the reaction is carried out at 80 ° C. or higher, the molecular weight varies depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be produced stably. Alternatively, a polyimide precursor can be easily obtained by dehydrating and condensing diester dicarboxylic acid and diamine using a phosphorus condensing agent or a carbodiimide condensing agent.

  Since the polyimide precursor obtained by this method is stable, it can be purified by reprecipitation by adding a solvent such as water or alcohol.

3) Polyamide acid silyl ester (indirect method)
A diamine and a silylating agent are reacted in advance to obtain a silylated diamine. If necessary, the silylated diamine is purified by distillation or the like. Then, the silylated diamine is dissolved in the dehydrated solvent, and tetracarboxylic dianhydride is gradually added while stirring, and the temperature is 0 to 120 ° C., preferably 5 to 80 ° C. A polyimide precursor is obtained by stirring for 72 hours. When the reaction is carried out at 80 ° C. or higher, the molecular weight varies depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be produced stably.

  As the silylating agent used here, it is preferable to use a silylating agent not containing chlorine because it is not necessary to purify the silylated diamine. Examples of the silylating agent not containing a chlorine atom include N, O-bis (trimethylsilyl) trifluoroacetamide, N, O-bis (trimethylsilyl) acetamide, and hexamethyldisilazane. N, O-bis (trimethylsilyl) acetamide and hexamethyldisilazane are particularly preferred because they do not contain fluorine atoms and are low in cost.

  In addition, amine-based catalysts such as pyridine, piperidine and triethylamine can be used in the silylation reaction of diamine in order to accelerate the reaction. This catalyst can be used as it is as a polymerization catalyst for the polyimide precursor.

4) Polyamide acid silyl ester (direct method)
The polyimide precursor is obtained by mixing the polyamic acid solution obtained by the method 1) and the silylating agent and stirring for 1 to 72 hours in the range of 0 to 120 ° C, preferably 5 to 80 ° C. When the reaction is carried out at 80 ° C. or higher, the molecular weight varies depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be produced stably.

  As the silylating agent used here, it is preferable to use a silylating agent not containing chlorine because it is not necessary to purify the silylated polyamic acid or the obtained polyimide. Examples of the silylating agent not containing a chlorine atom include N, O-bis (trimethylsilyl) trifluoroacetamide, N, O-bis (trimethylsilyl) acetamide, and hexamethyldisilazane. N, O-bis (trimethylsilyl) acetamide and hexamethyldisilazane are particularly preferred because they do not contain fluorine atoms and are low in cost.

  Any of the above production methods can be suitably carried out in an organic solvent, and as a result, a solution or solution composition containing a polyimide precursor can be easily obtained.

  Solvents used in preparing the polyimide precursor are, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide An aprotic solvent such as N, N-dimethylacetamide is preferred, but any type of solvent can be used without any problem as long as the raw material monomer component and the polyimide precursor to be produced are dissolved. The structure is not limited. As solvents, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α- Cyclic ester solvents such as methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, phenols such as m-cresol, p-cresol, 3-chlorophenol and 4-chlorophenol A system solvent, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably employed. Furthermore, other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran , Dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpenes, mineral spirit, petroleum A naphtha solvent can also be used. In addition, a solvent can also be used in combination of multiple types.

  In the present invention, the logarithmic viscosity of the polyimide precursor is not particularly limited, but the logarithmic viscosity in an N, N-dimethylacetamide solution having a concentration of 0.5 g / dL at 30 ° C. is 0.2 dL / g or more, more preferably 0. .3 dL / g or more, particularly preferably 0.4 dL / g or more. When the logarithmic viscosity is 0.2 dL / g or more, the molecular weight of the polyimide precursor is high, and the mechanical strength and heat resistance of the resulting polyimide are excellent.

  The polyimide precursor composition of the present invention includes a polyimide precursor and an imidazole compound, and may be prepared by adding an imidazole compound to a polyimide precursor solution or solution composition obtained by the above production method. it can. Moreover, a solvent may be removed or added as needed, and desired components other than an imidazole compound may be added. In addition, a tetracarboxylic acid component (tetracarboxylic dianhydride or the like), a diamine component, and an imidazole compound are added to a solvent, and the tetracarboxylic acid component and the diamine component are reacted in the presence of the imidazole compound. The polyimide precursor composition (solution composition containing a polyimide precursor and an imidazole compound) can also be obtained.

  The imidazole compound used in the present invention is not particularly limited as long as it is a compound having an imidazole skeleton. By adding an imidazole compound, a polyimide having a small thickness direction retardation can be obtained.

  In one embodiment, it is preferable to use a compound having a boiling point at 1 atm of less than 340 ° C., preferably 330 ° C. or less, more preferably 300 ° C. or less, particularly preferably 270 ° C. or less as the imidazole compound. By adding an imidazole compound having a boiling point at 1 atm of less than 340 ° C., preferably 330 ° C. or less, more preferably 300 ° C. or less, particularly preferably 270 ° C. or less, a more transparent polyimide may be obtained. .

  The imidazole compound used in the present invention is not particularly limited, and examples thereof include 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, and benzimidazole. 1,2-dimethylimidazole (boiling point at 1 atmosphere: 205 ° C.), 1-methylimidazole (boiling point at 1 atmosphere: 198 ° C.), 2-methylimidazole (boiling point at 1 atmosphere: 268 ° C.), imidazole (boiling point at 1 atmosphere) : 256 ° C.) and the like, and 1,2-dimethylimidazole and 1-methylimidazole are particularly preferable. An imidazole compound may be used individually by 1 type, and can also be used in combination of multiple types.

  In this invention, content of the imidazole type compound of a polyimide precursor composition is less than 4 mol with respect to 1 mol of repeating units of a polyimide precursor. When the content of the imidazole compound is 4 mol or more with respect to 1 mol of the repeating unit of the polyimide precursor, the storage stability of the polyimide precursor composition is deteriorated. The content of the imidazole compound is preferably 0.05 mol or more with respect to 1 mol of the repeating unit of the polyimide precursor, and is 2 mol or less with respect to 1 mol of the repeating unit of the polyimide precursor. preferable. Here, 1 mol of the repeating unit of the polyimide precursor corresponds to 1 mol of the tetracarboxylic acid component.

  The polyimide precursor composition of the present invention usually contains a solvent. The solvent used for the polyimide precursor composition of the present invention is not a problem as long as the polyimide precursor is dissolved, and the structure is not particularly limited. As solvents, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone , Cyclic ester solvents such as α-methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol Phenol solvents such as acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably employed. Furthermore, other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran , Dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpenes, mineral spirit, petroleum A naphtha solvent can also be used. Moreover, these can also be used combining multiple types. In addition, the solvent used when preparing a polyimide precursor can be used for the solvent of a polyimide precursor composition as it is.

  In the present invention, the total amount of the tetracarboxylic acid component and the diamine component is 5% by mass or more, preferably 10% by mass or more, more preferably 15%, based on the total amount of the solvent, the tetracarboxylic acid component and the diamine component. A ratio of not less than mass% is preferred. In general, the total amount of the tetracarboxylic acid component and the diamine component is 60% by mass or less, preferably 50% by mass or less, based on the total amount of the solvent, the tetracarboxylic acid component, and the diamine component. Is preferred. This concentration is a concentration approximately approximate to the solid content concentration resulting from the polyimide precursor, but if this concentration is too low, it becomes difficult to control the film thickness of the polyimide film obtained, for example, when producing a polyimide film. Sometimes.

In the present invention, the viscosity (rotational viscosity) of the polyimide precursor composition is not particularly limited, but the rotational viscosity measured at a temperature of 25 ° C. and a shear rate of 20 sec ⁻¹ using an E-type rotational viscometer is 0.01 to 1000 Pa · sec is preferable, and 0.1 to 100 Pa · sec is more preferable. Moreover, thixotropy can also be provided as needed. When the viscosity is in the above range, it is easy to handle when coating or forming a film, and the repelling is suppressed and the leveling property is excellent, so that a good film can be obtained.

  The polyimide precursor composition of the present invention includes chemical imidizing agents (acid anhydrides such as acetic anhydride, amine compounds such as pyridine and isoquinoline), antioxidants, fillers (inorganic particles such as silica, etc.) as necessary. ), Dyes, pigments, coupling agents such as silane coupling agents, primers, flame retardants, antifoaming agents, leveling agents, rheology control agents (flow aids), release agents and the like.

  The polyimide of the present invention can be obtained by imidizing the polyimide precursor composition of the present invention as described above (that is, subjecting the polyimide precursor to a dehydration ring-closing reaction). The imidization method is not particularly limited, and a known thermal imidation or chemical imidization method can be suitably applied. The form of the polyimide obtained can mention suitably a film, the laminated body of a polyimide film and another base material, a coating film, powder, a bead, a molded object, a foam.

  In the present invention, it is preferable to imidize the polyimide precursor composition by heat-treating the polyimide precursor composition at a maximum heating temperature exceeding 350 ° C. The maximum heating temperature of the heat treatment for imidization is more preferably higher than 380 ° C, and particularly preferably higher than 400 ° C. By setting the maximum heating temperature of the heat treatment for imidization to a temperature exceeding 350 ° C., more preferably a temperature exceeding 380 ° C., particularly preferably a temperature exceeding 400 ° C., the mechanical properties of the resulting polyimide are improved. To do. Although the upper limit of the maximum heating temperature of heat processing is not specifically limited, Usually, 500 degrees C or less is preferable.

  For example, the polyimide precursor composition of the present invention is cast and applied on a substrate, and the polyimide precursor composition on the substrate is heated to a maximum heating temperature of 350 ° C., more preferably 380 ° C., particularly preferably 400. A polyimide can be suitably manufactured by heat-processing at the temperature exceeding 0 degreeC and imidating a polyimide precursor. The heating profile is not particularly limited and can be selected as appropriate. However, from the viewpoint of productivity, it is preferable that the heat treatment time is short.

  In addition, the polyimide precursor composition of the present invention is cast and applied on a substrate, and preferably dried in a temperature range of 180 ° C. or less to form a polyimide precursor composition film on the substrate. In the state where the film of the obtained polyimide precursor composition is peeled off from the substrate and the end of the film is fixed, the maximum heating temperature exceeds 350 ° C., more preferably exceeds 380 ° C., and particularly preferably exceeds 400 ° C. A polyimide can be suitably manufactured also by heat-processing at temperature and imidizing a polyimide precursor.

  A more specific example of the method for producing the polyimide (polyimide film / substrate laminate or polyimide film) of the present invention will be described later.

  The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, but the linear thermal expansion coefficient from 150 ° C. to 250 ° C. when formed into a film is preferably 60 ppm / K or less, More preferably, it is 50 ppm / K or less, More preferably, it is 45 ppm / K or less, More preferably, it is 40 ppm / K or less, Most preferably, it is 35 ppm / K or less. When the linear thermal expansion coefficient is large, the difference in the linear thermal expansion coefficient with a conductor such as metal is large, which may cause problems such as an increase in warpage when a circuit board is formed.

  The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, but preferably has a total light transmittance (average light transmittance of a wavelength of 380 nm to 780 nm) in a film having a thickness of 10 μm. May be 86% or more, more preferably 87% or more, and particularly preferably 88% or more. When used for a display application or the like, if the total light transmittance is low, it is necessary to strengthen the light source, which may cause a problem that energy is applied.

  In particular, when a polyimide film such as a display application is used in an application where light is transmitted, it is desirable that the polyimide film has higher transparency. The polyimide (polyimide of the present invention) obtained from the polyimide precursor composition of the present invention is not particularly limited, but the light transmittance at a wavelength of 400 nm in a 10 μm thick film is preferably 75% or more, preferably 80%. Above, more preferably more than 80%, still more preferably 81% or more, particularly preferably 82% or more.

  In addition, although the film which consists of a polyimide (polyimide of this invention) obtained from the polyimide precursor composition of this invention also depends on a use, as thickness of a film, Preferably it is 0.1 micrometer-250 micrometers, More preferably, it is 1 micrometer-. It is 150 μm, more preferably 1 μm to 50 μm, and particularly preferably 1 μm to 30 μm. When the polyimide film is used for light transmission, if the polyimide film is too thick, the light transmittance may be lowered.

  The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, but the 1% weight loss temperature, which is an index of heat resistance of the polyimide film, is preferably 395 ° C. or more, more preferably It can be 430 ° C. or higher, more preferably 440 ° C. or higher, and particularly preferably 470 ° C. or higher. When a gas barrier film or the like is formed on a polyimide by forming a transistor on the polyimide or the like, if the heat resistance is low, swelling may occur between the polyimide and the barrier film due to outgas accompanying decomposition of the polyimide.

  The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, but the thickness direction retardation of the polyimide film is preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably 700 nm or less. Particularly preferably, it can be 600 nm or less. When the retardation in the thickness direction is large, there are cases where the color of transmitted light is not displayed correctly, the color is blurred, and the viewing angle is narrowed.

  The polyimide obtained from the polyimide precursor composition of the present invention, that is, the polyimide of the present invention has a small phase difference in the film thickness direction, and has excellent properties such as high transparency, bending resistance, and high heat resistance. Since it has a low coefficient of linear thermal expansion, it can be suitably used in applications such as a transparent substrate for display, a transparent substrate for touch panel, or a substrate for solar cell.

  Below, an example of the manufacturing method of a polyimide film / base material laminated body or a polyimide film using the polyimide precursor composition of this invention is described. However, it is not limited to the following method.

  For example, the polyimide precursor composition (varnish) of the present invention is cast on a substrate such as ceramic (glass, silicon, alumina, etc.), metal (copper, aluminum, stainless steel, etc.), heat resistant plastic film (polyimide film, etc.), etc. In a vacuum, in an inert gas such as nitrogen, or in the air, drying is performed in a temperature range of 20 to 180 ° C., preferably 20 to 150 ° C. using hot air or infrared rays. Next, the obtained polyimide precursor film is peeled off from the substrate or the polyimide precursor film from the substrate, and the end of the film is fixed, in vacuum, in an inert gas such as nitrogen, Alternatively, in the air, using hot air or infrared rays, for example, 200 to 500 ° C., preferably a maximum heating temperature of over 350 ° C., more preferably over 380 ° C., and particularly preferably over 400 ° C. / A substrate laminate or a polyimide film can be produced. In order to prevent the resulting polyimide film from being oxidized and deteriorated, it is desirable to carry out the heating imidization in a vacuum or in an inert gas. The thickness of the polyimide film here (in the case of a polyimide film / substrate laminate) is preferably 1 to 250 μm, more preferably 1 to 150 μm, for transportability in the subsequent steps.

  Also, the imidization reaction of the polyimide precursor, instead of the heat imidation by the heat treatment as described above, contains a dehydration cyclization reagent such as acetic anhydride in the presence of a tertiary amine such as pyridine or triethylamine. It is also possible to carry out by chemical treatment such as immersion in a solution. In addition, these dehydrating cyclization reagents are previously charged and stirred in a polyimide precursor composition (varnish), and cast and dried on a base material to obtain a partially imidized polyimide precursor. A polyimide film / base material laminate or a polyimide film can be obtained by further heat treatment as described above.

  The polyimide film / base laminate or the polyimide film thus obtained can be used to form a flexible conductive substrate by forming a conductive layer on one side or both sides thereof.

  A flexible conductive substrate can be obtained, for example, by the following method. That is, as a first method, the polyimide film / substrate laminate is not peeled off from the substrate, and the surface of the polyimide film is sputtered, vapor-deposited, printed, etc. by a conductive substance (metal or metal oxide). A conductive layer of conductive layer / polyimide film / base material is produced. Then, if necessary, a transparent and flexible conductive substrate comprising the conductive layer / polyimide film laminate can be obtained by peeling the conductive layer / polyimide film laminate from the substrate.

  As a second method, the polyimide film is peeled off from the substrate of the polyimide film / substrate laminate to obtain a polyimide film, and a conductive substance (metal or metal oxide, conductive organic substance, A conductive layer of conductive carbon, etc.) is formed in the same manner as in the first method, and is a transparent and flexible conductive layer comprising a conductive layer / polyimide film laminate and a conductive layer / polyimide film laminate / conductive layer. A substrate can be obtained.

  In the first and second methods, if necessary, before forming a conductive layer on the surface of the polyimide film, a gas barrier layer such as water vapor or oxygen, light adjustment, etc. by sputtering, vapor deposition or gel-sol method. An inorganic layer such as a layer may be formed.

  The conductive layer is preferably formed with a circuit by a photolithography method, various printing methods, an inkjet method, or the like.

  The substrate of the present invention thus obtained has a circuit of a conductive layer on the surface of a polyimide film composed of the polyimide of the present invention through a gas barrier layer or an inorganic layer as necessary. This substrate is flexible, has excellent transparency, bendability, and heat resistance, and further has a very low linear thermal expansion coefficient and excellent solvent resistance, so that a fine circuit can be easily formed. Therefore, this board | substrate can be used suitably as a board | substrate for displays, a touch panel, or a solar cell.

  That is, a transistor (inorganic transistor, organic transistor) is further formed on this substrate by vapor deposition, various printing methods, an ink jet method or the like to manufacture a flexible thin film transistor, and a liquid crystal element, an EL element, a photoelectric transistor for a display device are manufactured. It is suitably used as an element.

  Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples. In addition, this invention is not limited to a following example.

  In each of the following examples, the evaluation was performed by the following method.

<Evaluation of polyimide precursor solution (varnish)>
[Storage stability]
If the varnish is stored at 23 ° C. and is in a uniform state with fluidity after 3 days,
If it becomes cloudy or gelled after 3 days, it is marked as x.

<Evaluation of polyimide film>
[400 nm light transmittance, total light transmittance]
Using a UV-visible spectrophotometer / V-650DS (manufactured by JASCO), the light transmittance at 400 nm and the total light transmittance (average transmittance at 380 nm to 780 nm) of a polyimide film having a thickness of about 10 μm were measured. The light transmittance at 400 nm and the total light transmittance were calculated using the Lambert-Beer formula with the total light transmittance being 10% and the light transmittance at 400 nm having a thickness of 10 μm and the total light transmittance were calculated. The calculation formula is shown below.

Log ₁₀ ((T ₁ +10) / 100) = 10 / L × (Log ₁₀ ((T ₁ ′ +10) / 100))
Log ₁₀ ((T ₂ +10) / 100) = 10 / L × (Log ₁₀ ((T ₂ ′ +10) / 100))
T ₁ : Light transmittance (%) at 400 nm of a 10 μm-thick polyimide film with a reflectance of 10%
T ₁ ′: measured light transmittance at 400 nm (%)
T ₂ : Total light transmittance (%) of a 10 μm-thick polyimide film with a reflectance of 10%
T ₂ ': Measured total light transmittance (%)
L: Film thickness of the measured polyimide film (μm)

[Elastic modulus, elongation at break]
A polyimide film having a thickness of about 10 μm is punched into a dumbbell shape conforming to IEC450 standard to make a test piece. Using ENSILON manufactured by ORIENTEC, the initial elastic modulus and elongation at break are 30 mm between chucks and a pulling speed of 2 mm / min. It was measured.

[Linear thermal expansion coefficient (CTE)]
A polyimide film having a thickness of about 10 μm is cut into a strip having a width of 4 mm to form a test piece, and TMA / SS6100 (manufactured by SII Nano Technology Co., Ltd.) is used. The temperature was raised to 500 ° C in minutes. The linear thermal expansion coefficient from 150 ° C. to 250 ° C. was determined from the obtained TMA curve.

[1% weight loss temperature]
A polyimide film having a film thickness of about 10 μm was used as a test piece, and the temperature was raised from 25 ° C. to 600 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen stream using a calorimeter measuring device (Q5000IR) manufactured by TA Instruments. From the obtained weight curve, a 1% weight loss temperature was determined.

[Thickness direction retardation of film (R _th )]
A polyimide film having a thickness of 10 μm was used as a test piece, and a phase difference measurement of the film was performed using a phase difference measuring device (KOBRA-WR) manufactured by Oji Scientific Instruments with an incident angle of 40 °. From the obtained phase difference, the thickness direction retardation of a film having a thickness of 10 μm was determined.

  Abbreviations, purity, etc. of raw materials used in the following examples are as follows.

[Diamine component]
tra-DACH: trans-1,4-diaminocyclohexane [Purity: 99.1% (GC analysis)]
DABAN: 4,4′-diaminobenzanilide [Purity: 99.90% (GC analysis)]
PPD: p-phenylenediamine [Purity: 99.9% (GC analysis)]
4,4′-ODA: 4,4′-oxydianiline [Purity: 99.9% (GC analysis)]
BAPB: 4,4′-bis (4-aminophenoxy) biphenyl [Purity: 99.93% (HPLC analysis)]
[Tetracarboxylic acid component]
s-BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride [purity 99.9% (H-NMR analysis)]
a-BPDA: 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride [purity 99.6% (H-NMR analysis)]
PMDA-HS: 1R, 2S, 4S, 5R-cyclohexanetetracarboxylic dianhydride [purity: 99.9% (GC analysis)]
CpODA-tee: trans-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride CpODA-cee: cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid Anhydrous CpODA: Mixture of CpODA-tee and CpODA-ce PACDA: N, N ′-(1,4-phenylene) bis (1,3-dioxooctahydroisobenzofuran-5-carboxamide)

[solvent]
NMP: N-methyl-2-pyrrolidone

  Table 1-1 shows tetracarboxylic acid components used in Examples and Comparative Examples, Table 1-2 shows Examples and Comparative Examples, and Diamine Components Used in Comparative Examples, Table 1-3 Examples and Comparative Examples Imidazole and Imidazoline The structural formula of the compound is described.

[Synthesis Example 1]
In a reaction vessel substituted with nitrogen gas, 90.91 g (0.4 mol) of DABAN and 64.88 g (0.6 mol) of PPD were added, N-methyl-2-pyrrolidone was charged, and the total mass of monomers (diamine component and 2835.90 g of an amount such that the total of the carboxylic acid components was 16% by mass was added and stirred at room temperature for 1 hour. To this solution, 384.38 g (1.0 mol) of CpODA was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish A).

[Synthesis Example 2]
DABAN 90.91 g (0.4 mol), PPD 54.07 g (0.5 mol) and BAPB 36.84 g (0.1 mol) were placed in a reaction vessel substituted with nitrogen gas, and N-methyl-2- Pyrrolidone was added in an amount of 2972.56 g so that the total monomer weight (total of diamine component and carboxylic acid component) was 16% by mass and stirred at room temperature for 1 hour. To this solution, 384.38 g (1.0 mol) of CpODA was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish B).

[Synthesis Example 3]
In a reaction vessel substituted with nitrogen gas, 22.73 g (0.100 mol) of DABAN was placed, N-methyl-2-pyrrolidone was charged, and the total monomer mass (total of diamine component and carboxylic acid component) was 16% by mass. An amount of 3211.16 g was added and stirred at room temperature for 1 hour. To this solution, 38.44 g (0.100 mol) of CpODA was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish C).

[Synthesis Example 4]
In a reaction vessel substituted with nitrogen gas, 15.91 g (0.070 mol) of DABAN and 3.24 g (0.030 mol) of PPD were added, N-methyl-2-pyrrolidone was charged, and the total mass of monomers (diamine component and An amount of 302.35 g in which the total of carboxylic acid components was 16% by mass was added and stirred at room temperature for 1 hour. To this solution, 38.44 g (0.100 mol) of CpODA was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish D).

[Synthesis Example 5]
In a reaction vessel substituted with nitrogen gas, 11.36 g (0.050 mol) of DABAN, 4.34 g (0.040 mol) of PPD, and 2.00 g (0.010 mol) of 4,4′-ODA were placed. -294.74g of the quantity from which the preparation monomer total mass (total of a diamine component and a carboxylic acid component) will be 16 mass% was added to methyl-2-pyrrolidone, and it stirred at room temperature for 1 hour. To this solution, 38.44 g (0.100 mol) of CpODA was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish E).

[Synthesis Example 6]
Into a reaction vessel substituted with nitrogen gas, 20.02 g (0.100 mol) of 4,4′-ODA was placed, N-methyl-2-pyrrolidone was charged, and the total mass of monomers (total of diamine component and carboxylic acid component) Was added in an amount of 17% by mass and stirred at room temperature for 1 hour. To this solution, 22.41 g (0.100 mmol) of PMDA-HS was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish F).

[Synthesis Example 7]
In a reaction vessel substituted with nitrogen gas, 22.73 g (0.100 mol) of DABAN was put, N-methyl-2-pyrrolidone was charged, and the total monomer mass (total of diamine component and carboxylic acid component) was 20% by mass. An amount of 296.29 g was added and stirred at room temperature for 1 hour. To this solution, 51.35 g (0.100 mol) of PACDA was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish G).

[Synthesis Example 8]
In a reaction vessel substituted with nitrogen gas, 10.81 g (0.100 mol) of tra-DACH was charged, N-methyl-2-pyrrolidone was charged, and the total monomer mass (total of diamine component and carboxylic acid component) was 12 mass. % 2950.64 g was added and stirred at room temperature for 1 hour. To this solution, 28.69 g (0.0975 mol) of s-BPDA and 0.74 g (0.0025 mol) of a-BPDA were gradually added. The mixture was stirred at 50 ° C. for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish H).

[Example 1]
0.05 g (0.5 mmol) of 1,2-dimethylimidazole and 0.05 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.05 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

[Example 2]
1,5-dimethylimidazole (0.15 g, 1.6 mmol) and N-methyl-2-pyrrolidone (0.15 g) were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.16 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 3
1,9-dimethylimidazole (0.19 g, 2.0 mmol) and N-methyl-2-pyrrolidone (0.19 g) were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.2 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 4
0.96 g (10.0 mmol) of 1,2-dimethylimidazole and 0.38 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 1.0 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 5
1.92 g (20.0 mmol) of 1,2-dimethylimidazole and 0.38 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the amount of 1,2-dimethylimidazole relative to 1 mol of the repeating unit of the polyimide precursor is 2.0 mol.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 6
A uniform solution was obtained by adding 0.04 g (0.5 mmol) of 1-methylimidazole and 0.04 g of N-methyl-2-pyrrolidone to the reaction vessel. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1-methylimidazole is 0.05 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 7
0.08 g (1.0 mmol) of 1-methylimidazole and 0.08 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1-methylimidazole is 0.1 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 8
A uniform solution was obtained by adding 0.16 g (2.0 mmol) of 1-methylimidazole and 0.16 g of N-methyl-2-pyrrolidone to the reaction vessel. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1-methylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 9
A uniform solution was obtained by adding 0.33 g (4.0 mmol) of 1-methylimidazole and 0.33 g of N-methyl-2-pyrrolidone to the reaction vessel. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1-methylimidazole is 0.4 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 10
0.16 g (2.0 mmol) of 2-methylimidazole and 0.16 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the amount of 2-methylimidazole relative to 1 mol of the repeating unit of the polyimide precursor is 0.2 mol.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 11
0.14 g (2.0 mmol) of imidazole and 0.14 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, imidazole is 0.2 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 12
0.29 g (2.0 mmol) of 2-phenylimidazole and 0.29 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 2-phenylimidazole is 0.2 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 13
A uniform solution was obtained by adding 0.24 g (2.0 mmol) of benzimidazole and 0.24 g of N-methyl-2-pyrrolidone to the reaction vessel. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. Calculating from the charged amount, benzimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

[Comparative Example 1]
Varnish A obtained in Synthesis Example 1 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 410 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

[Comparative Example 2]
1.92 g (40.0 mmol) of 1,2-dimethylimidazole and 0.38 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 4.0 mol per 1 mol of the repeating unit of the polyimide precursor. When the obtained polyimide precursor solution was stored at 23 ° C., the polyimide precursor solution gelled by the third day.

[Reference Example 1]
1,9-dimethylimidazole (0.19 g, 2.0 mmol) and N-methyl-2-pyrrolidone (0.19 g) were added to the reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the amount of 1,2-dimethylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) from room temperature to 350 ° C. as it is, and thermally imidized. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-1.

Example 14
0.05 g (0.5 mmol) of 1,2-dimethylimidazole and 0.05 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.05 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-2.

Example 15
0.10 g (1.0 mmol) of 1,2-dimethylimidazole and 0.10 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.1 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-2.

Example 16
1,9-dimethylimidazole (0.19 g, 2.0 mmol) and N-methyl-2-pyrrolidone (0.19 g) were added to the reaction vessel to obtain a uniform solution. 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the amount of 1,2-dimethylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-2.

Example 17
A uniform solution was obtained by adding 0.16 g (2.0 mmol) of 1-methylimidazole and 0.16 g of N-methyl-2-pyrrolidone to the reaction vessel. 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1-methylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-2.

[Comparative Example 3]
Varnish B obtained in Synthesis Example 2 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 410 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-2.

[Comparative Example 4]
0.10 g (1.0 mmol) of 2-ethyl-2-imidazoline and 0.20 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 2-ethyl-2-imidazoline is 0.1 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-2.

[Comparative Example 5]
0.20 g (2.0 mmol) of 2-ethyl-2-imidazoline and 0.40 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. When 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol relative to the molecular weight of the polyimide precursor repeating unit in varnish B) was added to the solution, the varnish gelled. Even if it was stirred at room temperature for 3 hours, a uniform polyimide precursor solution could not be obtained. When calculated from the charged amount, 2-ethyl-2-imidazoline is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

[Comparative Example 6]
0.49 g (5.0 mmol) of 2-ethyl-2-imidazoline and 0.98 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. When 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol relative to the molecular weight of the polyimide precursor repeating unit in varnish B) was added to the solution, the varnish gelled. Even if it was stirred at room temperature for 3 hours, a uniform polyimide precursor solution could not be obtained. When calculated from the charged amount, the amount of 2-ethyl-2-imidazoline is 0.5 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

[Comparative Example 7]
0.25 g (3.0 mmol) of 2-methyl-2-imidazoline and 0.25 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the amount of 2-methyl-2-imidazoline is 0.3 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-2.

[Comparative Example 8]
0.44 g (3.0 mmol) of 2-phenylimidazoline and 0.44 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 35.39 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the amount charged, 2-phenylimidazoline is 0.3 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-2.

Example 18
0.10 g (1.0 mmol) of 1,2-dimethylimidazole and 0.10 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. To the solution, 38.23 g of varnish C obtained in Synthesis Example 3 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish C) was added and stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.1 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

[Comparative Example 9]
Varnish C obtained in Synthesis Example 3 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 410 ° C. on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

Example 19
0.10 g (1.0 mmol) of 1,2-dimethylimidazole and 0.10 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. To the solution, 35.99 g of varnish D obtained in Synthesis Example 4 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish D) was added and stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.1 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

[Comparative Example 10]
The varnish D obtained in Synthesis Example 4 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 410 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

Example 20
0.10 g (1.0 mmol) of 1,2-dimethylimidazole and 0.10 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. To the solution was added 35.09 g of varnish E obtained in Synthesis Example 5 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish E), and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.1 mol with respect to 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, heated in a nitrogen atmosphere (oxygen concentration 200 ppm or less) from room temperature to 410 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

[Comparative Example 11]
Varnish E obtained in Synthesis Example 5 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 410 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

Example 21
1,9-dimethylimidazole (0.19 g, 2.0 mmol) and N-methyl-2-pyrrolidone (0.19 g) were added to the reaction vessel to obtain a uniform solution. 24.97 g of varnish F obtained in Synthesis Example 6 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish F) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the amount of 1,2-dimethylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) from room temperature to 400 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

[Comparative Example 12]
Varnish F obtained in Synthesis Example 6 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 400 ° C. directly on the glass substrate in a nitrogen atmosphere (oxygen concentration 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

[Example 22]
1,9-dimethylimidazole (0.19 g, 2.0 mmol) and N-methyl-2-pyrrolidone (0.19 g) were added to the reaction vessel to obtain a uniform solution. 37.04 g of varnish G obtained in Synthesis Example 7 (10 mmol with respect to the molecular weight of the polyimide precursor repeating unit in varnish G) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the amount of 1,2-dimethylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) from room temperature to 350 ° C. as it is, and thermally imidized. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

[Comparative Example 13]
Varnish G obtained in Synthesis Example 7 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 350 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

Example 23
1,9-dimethylimidazole (0.19 g, 2.0 mmol) and N-methyl-2-pyrrolidone (0.19 g) were added to the reaction vessel to obtain a uniform solution. 33.53 g of varnish H obtained in Synthesis Example 8 (10 mmol with respect to the molecular weight of the polyimide precursor repeating unit in varnish H) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the amount of 1,2-dimethylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

  A polyimide precursor solution filtered through a PTFE membrane filter is applied to a glass substrate, and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) from room temperature to 370 ° C. as it is, and thermally imidized to be colorless. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

[Comparative Example 14]
Varnish H obtained in Synthesis Example 8 filtered through a PTFE membrane filter was applied to a glass substrate and heated from room temperature to 370 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

  The result of having measured the characteristic of this polyimide film is shown in Table 2-3.

  From the results shown in Tables 2-1 to 2-3, a polyimide precursor containing an imidazole compound (1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, benzimidazole, or imidazole). It can be seen that the polyimide obtained from the body composition has a small thickness direction retardation (Examples 1 to 13 and Comparative Example 1, Examples 14 to 17 and Comparative Example 3, Example 18 and Comparative Example 9, Example) 19 and Comparative Example 10, Example 20 and Comparative Example 11, Example 21 and Comparative Example 12, Example 22 and Comparative Example 13, Example 23 and Comparative Example 14). Moreover, when 1, 2- dimethylimidazole, 1-methylimidazole, 2-methylimidazole, or imidazole is used, it turns out that the transmittance | permeability is also improved (Examples 1-11 and Comparative Example 1, implementation). Examples 14 to 17 and Comparative Example 3, Example 18 and Comparative Example 9, Example 19 and Comparative Example 10, Example 20 and Comparative Example 11, Example 21 and Comparative Example 12, Example 22 and Comparative Example 13, Example Example 23 and Comparative Example 14). Furthermore, it turns out that it is excellent also in storage stability as content of an imidazole type compound is less than 4 mol with respect to 1 mol of repeating units of a polyimide precursor (Examples 1-13 and Comparative Example 2). Moreover, regarding the mechanical properties, it can be seen that the elongation at break increases by setting the maximum heating temperature of the heat treatment for imidization to 410 ° C. exceeding 350 ° C. (Example 3 and Reference Example 1). .

  As described above, the polyimide obtained from the polyimide precursor composition of the present invention has excellent light transmittance, mechanical properties, and low linear thermal expansion coefficient in addition to a small thickness direction retardation. The polyimide film of the present invention can be suitably used as a transparent substrate that is colorless and transparent and capable of forming a fine circuit, such as for display applications.

  According to the present invention, a polyimide having excellent transparency and having a smaller thickness direction retardation even in the same composition, or a polyimide having a small thickness direction retardation, excellent transparency, and excellent mechanical properties can be obtained. A polyimide precursor composition (solution composition containing a polyimide precursor) and a method for producing polyimide can be provided. The polyimide obtained from this polyimide precursor composition is highly transparent and has a small thickness direction retardation, and also has a low linear thermal expansion coefficient and facilitates the formation of fine circuits. It can be suitably used for forming substrates for touch panels, solar cells, and the like.

Claims (12)

A polyimide precursor containing a repeating unit represented by the following chemical formula (1) or a repeating unit represented by the following chemical formula (2);
Including imidazole compounds,
Content of an imidazole type compound is less than 4 mol with respect to 1 mol of repeating units of a polyimide precursor, The polyimide precursor composition characterized by the above-mentioned.

(In the formula, X ₁ is a tetravalent group having an alicyclic structure, Y ₁ is a divalent group having an aromatic ring, and R ₁ and R ₂ are each independently hydrogen, C 1-6. Or an alkylsilyl group having 3 to 9 carbon atoms.)

(In the formula, X ₂ is a tetravalent group having an aromatic ring, Y ₂ is a divalent group having an alicyclic structure, and R ₃ and R ₄ are each independently hydrogen, C 1-6. Or an alkylsilyl group having 3 to 9 carbon atoms.)   2. The polyimide precursor composition according to claim 1, wherein the polyimide obtained from the polyimide precursor composition has a light transmittance of a wavelength of 400 nm in a film having a thickness of 10 μm of 75% or more.   3. The polyimide precursor composition according to claim 1, wherein the content of the imidazole compound is 0.05 mol or more and 2 mol or less with respect to 1 mol of the repeating unit of the polyimide precursor.   The polyimide precursor composition according to any one of claims 1 to 3, wherein the imidazole compound has a boiling point at 1 atm of less than 340 ° C.   The imidazole compound is any one of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, and benzimidazole. A polyimide precursor composition according to claim 1.   A polyimide precursor composition according to any one of claims 1 to 5, wherein the polyimide precursor composition is heat-treated at a maximum heating temperature exceeding 350 ° C to imidize the polyimide precursor. Applying the polyimide precursor composition according to any one of claims 1 to 5 on a substrate;
The method for producing polyimide according to claim 6, further comprising a step of heat-treating the polyimide precursor composition on the substrate at a maximum heating temperature exceeding 350 ° C. to imidize the polyimide precursor.   The method for producing polyimide according to claim 6 or 7, wherein a maximum heating temperature of the heat treatment exceeds 400 ° C.   The polyimide manufactured by the method in any one of Claims 6-8.   The polyimide according to claim 9, wherein a light transmittance at a wavelength of 400 nm in a film having a thickness of 10 μm is 75% or more.   The polyimide film manufactured by the method in any one of Claims 6-8.   A substrate for a display, a touch panel, or a solar cell, comprising the polyimide according to claim 9 or 10, or the polyimide film according to claim 11.