JP6721070B2 - Polyimide precursor composition, method for producing polyimide, polyimide, polyimide film, and substrate - Google Patents

Description

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

In recent years, with the advent of the advanced information society, optical materials such as optical fibers and optical waveguides in the field of optical communication, liquid crystal alignment films in the field of display devices, protective films for color filters, and the like have been developed. In the field of display devices, in particular, as a substitute for a glass substrate, a lightweight and highly flexible plastic substrate is being studied, and a display that can be bent or rolled is being actively developed. Therefore, there is a demand for higher performance optical materials that can be used for such applications.

Aromatic polyimides are essentially tan colored due to intramolecular conjugation and charge transfer complex formation. Therefore, as a means of suppressing coloring, for example, introduction of a fluorine atom into the molecule, imparting flexibility to the main chain, introduction of a bulky group as a side chain, or the like inhibits intramolecular conjugation or formation of a charge transfer complex. Then, the method of expressing transparency is proposed.

In addition, a method of developing transparency by using a semi-alicyclic or wholly alicyclic polyimide that does not form a charge transfer complex in principle has also been proposed.

For example, Patent Documents 1 to 3 disclose highly transparent semi-alicyclic polyimides that use 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 transparent semi-alicyclic polyimides using an alicyclic tetracarboxylic dianhydride as a tetracarboxylic acid component and an aromatic diamine as a diamine component. Has been done.

In Non-Patent Document 1, as a tetracarboxylic acid component, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic A polyimide using an acid dianhydride is disclosed. Further, the norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride used here is 6 It is stated to contain a class of stereoisomers. Also in Patent Document 8, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid is used as the tetracarboxylic acid component. Polyimides using dianhydrides are disclosed.

However, depending on the application, particularly in the field of display devices and the like, in addition to high transparency, it is desired to reduce the thickness direction retardation. Transmission through a film having a large thickness direction retardation may cause problems such as incorrect display of colors, color bleeding, and narrow viewing angle. Therefore, in the field of display devices in particular, a polyimide film having a small thickness direction retardation is required.

On the other hand, Patent Document 9 discloses a polyimide formed by heating a coating liquid prepared by mixing a polyimide precursor (polyamic acid) with an imidazoline compound and/or an imidazole compound. More specifically, in Example 1, 2,4-dimethyl was added to a solution of a polyamic acid obtained from 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and 4,4′-diaminobiphenyl ether. A solution containing imidazoline is applied onto a substrate and heated at 200° C. for 1 hour to obtain an aromatic polyimide film having a film thickness of 1000 Å (0.1 μm). In Example 2, a solution of 2-ethylimidazoline and 1,2-dimethylimidazole added to a solution of a polyamic acid obtained from pyromellitic dianhydride and 4,4′-diaminobiphenyl ether was coated on a substrate, By heating at 150° C. for 1 hour, an aromatic polyimide film having a film thickness of 800 Å (0.08 μm) is obtained. In Patent Document 9, the addition of an imidazoline-based compound and/or an imidazole-based compound avoids the remarkable dark brown coloring, and a liquid crystal display device having a high light transmittance and excellent transparency can be obtained. Is described. However, the light transmittance at a wavelength of 400 nm of the liquid crystal display device using the polyimide film (liquid crystal alignment film) of Example 1 was 82% (polyimide film thickness: 0.1 μm), and the polyimide film (liquid crystal alignment film) of Example 2 was used. The liquid crystal display device using is having a light transmittance of 83% at a wavelength of 400 nm (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, in Patent Document 10, a polyimide precursor resin and a curing accelerator for the polyimide precursor resin such as imidazole and N-methylimidazole are 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 on a substrate, and the formation of the polyimide resin layer by drying and imidization in the subsequent heat treatment is completed within the range of 280 to 380° C., It is described that the coefficient of linear thermal expansion can be controlled low by using these curing accelerators. Patent Document 10 also describes that it is preferable to use a curing accelerator having a boiling point of higher than 120° C., and it is preferable to select a curing accelerator having a boiling point not higher than the upper limit temperature of the heat treatment. However, it is described that a curing accelerator having a boiling point of, for example, 400° C. or higher has a high rate 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. 2008/146637 JP-A-2002-69179 JP, 2002-146021, A International Publication No. 2011/099518 JP 61-267030 A JP, 2008-115378, A

Polymers Collection, Vol. 68, No. 3, P.I. 127-131 (2011)

The present invention has been made in view of the above situation, is a polyimide having excellent transparency, the thickness direction retardation is smaller polyimide in the same composition, or the thickness direction retardation is small, mechanical An object of the present invention is to provide a polyimide precursor composition (a solution composition containing a polyimide precursor) that provides a polyimide having excellent properties and excellent transparency, and a method for producing the polyimide.

The present invention relates to the following items.
1. A repeating unit represented by the following chemical formula (1) or a polyimide precursor containing 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, and have 1 to 6 carbon atoms. 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, and have 1 to 6 carbon atoms. Or an alkylsilyl group having 3 to 9 carbon atoms.)

2. The polyimide obtained from this polyimide precursor composition has a light transmittance of 400% at a wavelength of 400 nm in a film having a thickness of 10 μm of 75% or more.
3. Content of the said imidazole type compound is 0.05 mol or more and 2 mol or less with respect to 1 mol of repeating units of a polyimide precursor, The polyimide precursor composition of said claim|item 1 or 2 characterized by the above-mentioned.
4. The boiling point of the imidazole-based compound at 1 atm is less than 340° C., The polyimide precursor composition according to any one of Items 1 to 3 above.
5. Any of the above items 1 to 4, wherein the imidazole compound is any one of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, or benzimidazole. A polyimide precursor composition as described in.
6. Item 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 of higher than 350°C to imidize the polyimide precursor.
7. A step of applying the polyimide precursor composition according to any one of Items 1 to 5 on a substrate,
The polyimide precursor composition on a base material is heat-processed at a maximum heating temperature of higher than 350° C. to imidize the polyimide precursor, and the method for producing a polyimide according to the above item 6.
8. The method for producing a polyimide according to Item 6 or 7, wherein the 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 film having a thickness of 10 µm has a light transmittance of 400% or more at a wavelength of 400 nm.
11. Item 9. A polyimide film produced by the method according to any one of items 6 to 8.
12. A substrate for a display, a touch panel, or a solar cell, which comprises 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, a polyimide having a smaller thickness direction retardation even with the same composition, or a thickness direction retardation being smaller, having excellent mechanical properties, and further having excellent transparency. It is possible to provide the obtained polyimide precursor composition (solution composition containing a polyimide precursor) and a method for producing a polyimide.

The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) has high transparency, a small thickness direction retardation, and a low linear thermal expansion coefficient, which facilitates formation of fine circuits. And can be preferably used for forming a substrate for display applications and the like. In addition, the polyimide of the present invention can be preferably used for forming a substrate for a touch panel or a solar cell.

A polyimide precursor composition of the present invention contains a polyimide precursor containing at least one 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 based on 1 mol of the repeating unit of the polyimide precursor.

A polyimide obtained from a polyimide precursor containing the repeating unit represented by the chemical formula (1) or at least one 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 may cause coloring is not preferred. However, by adding the imidazole compound to the polyimide precursor composition in a ratio of less than 4 mol, preferably 0.05 mol or more and 2 mol or less, relative to 1 mol of the repeating unit of the polyimide precursor, high transparency can be obtained. A polyimide having a small retardation in the thickness direction can be obtained while keeping it. That is, according to the present invention, a polyimide having a smaller thickness direction retardation while maintaining high transparency can be obtained from a polyimide precursor having the same composition. Moreover, when an imidazole compound having a boiling point of less than 340° C. at 1 atm is used, the transparency of the obtained 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 a heat treatment at a temperature higher than 350° C., particularly preferably higher than 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 obtained polyimide are improved. That is, according to the present invention, a polyimide having high transparency, a small thickness direction retardation, and excellent mechanical properties can be obtained.

As described above, the polyimide precursor composition of the present invention includes a polyimide precursor containing at least one repeating unit represented by the chemical formula (1) or the repeating unit represented by the 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 group having an aromatic ring having 6 to 40 carbon atoms. Groups of are preferred.

Examples of the tetracarboxylic acid component providing 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(cyclohexane -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] ] Decane-3,4,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5]deca-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-dimethanonaphthalene-2c,3c,6c,7c-tetracarboxylic acid, (4arH,8acH) -Decahydro-1t,4t:5c,8c-dimethanonaphthalene-2t,3t,6c,7c-tetracarboxylic acid, tetracarboxylic acid dianhydrides thereof, tetracarboxylic acid silyl ester, tetracarboxylic acid ether Examples thereof include derivatives such as stell and tetracarboxylic acid chloride. The tetracarboxylic acid component may be used alone or in combination of two or more.

Examples of the diamine component that provides the repeating unit of the chemical formula (1) include 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-phenylene bis(p-aminobenzamide), 4-aminophenoxy-4-diaminobenzoate, bis(4-aminophenyl)terephthalate, biphenyl-4,4'-dicarboxylic acid bis(4-amino) Phenyl) ester, p-phenylene bis(p-aminobenzoate), bis(4-aminophenyl)-[1,1'-biphenyl]-4,4'-dicarboxylate, [1,1'-biphenyl]- 4,4'-diylbis(4-aminobenzoate), 4,4'-oxydianiline, 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(trifluoromethyl)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 Examples include -aminoanilino)-6-ethylamino-1,3,5-triazine and 2,4-bis(4-aminoanilino)-6-anilino-1,3,5-triazine. The diamine component may be used alone or in combination of two or more.

The polyimide precursor containing at least one kind of the repeating unit represented by the chemical formula (1) may include other repeating unit other than the repeating unit represented by the chemical formula (1). The tetracarboxylic acid component and the diamine component that give other repeating units are not particularly limited, and any other known aromatic or aliphatic tetracarboxylic acid or known aromatic or aliphatic diamine 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 group having an alicyclic structure having 4 to 40 carbon atoms. Groups of are preferred.

Examples of the tetracarboxylic acid component giving 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'-benzophenonetetracarboxylic 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, bisdicarboxyphenoxydiphenyl sulfide, Examples thereof include sulfonyldiphthalic acid and derivatives thereof such as tetracarboxylic acid dianhydride, tetracarboxylic acid silyl ester, tetracarboxylic acid ester, and tetracarboxylic acid chloride. The tetracarboxylic acid component may be used alone or in combination of two or more.

Examples of the diamine component giving 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, diaminomethylbicycloheptane, 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'-tetramethyl-1,1'-spirobiindane. The diamine component may be used alone or in combination of two or more.

The polyimide precursor containing at least one kind of the repeating unit represented by the chemical formula (2) can contain other repeating unit other than the repeating unit represented by the chemical formula (2). The tetracarboxylic acid component and the diamine component that give other repeating units are not particularly limited, and any other known aromatic or aliphatic tetracarboxylic acid or known aromatic or aliphatic diamine 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 type of repeating unit represented by the chemical formula (1) and at least one type of 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% based on all repeating units, It is more preferably 20 mol% or less, and further preferably 10 mol% or less.

In one embodiment, as the polyimide precursor, for example, a polyimide precursor containing a repeating unit represented by the following chemical formula (1-1) is preferable, and 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 at least 80 mol% based on all the repeating units. A polyimide precursor is more preferred.

（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 one of the 5-position and the 6-position of two norbornane rings (bicyclo[2.2.1]heptane). Group represented by -COOR ₁ or a group represented by -COOR ₂ in which an acid group of ₁ forms an amide bond (-CONH-) by reacting with an amino group, and _one of which does not form an amide bond. Is shown. That is, in the chemical formula (1-1), the chemical formula (1-2), and the chemical formula (1-3), four structural isomers, that is, (i) a group represented by —COOR ₁ at the 5 position is represented. A group having 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 by 6''position; Having a group represented by -CONH-A- in (iii) a group represented by -COOR ₁ in the 5-position, a group represented by -CONH- in the 6-position, and a 6''-position. Having a group represented by -COOR ₂ at 5''-position and a group represented by -CONH-A- at the 5'' position, (iv) a group represented by -COOR ₁ at the 6-position at the 5-position All of those having a group represented by CONH-, a group represented by -COOR ₂ at the 6" position, and a group represented by -CONH-A- at the 5" position are included.

Furthermore, in the polyimide precursor, A is a repeating unit represented by the chemical formula (1-1), which is a group represented by the following chemical formula (1-A), and 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 represented by

（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 independently represents an integer of 0 to 3, and n independently represents an integer of 0 to 3. 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 each independently represent 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 and/or cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acids And the like (the tetracarboxylic acids and the like represent tetracarboxylic acid and tetracarboxylic acid dianhydride, tetracarboxylic acid silyl ester, tetracarboxylic acid ester, tetracarboxylic acid derivative such as tetracarboxylic acid chloride) Component, a diamine component having an aromatic ring, and more preferably a chemical formula (1-1), a chemical formula (1-2) or a chemical formula (1-3) in which A is a group represented by the chemical formula (1-A). Is a polyimide precursor obtained from a diamine component containing a diamine component giving the repeating unit of

Examples of the tetracarboxylic acid component giving the repeating unit of the chemical formula (1-1) include norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6. One type such as 6″-tetracarboxylic acids may be used alone, or a plurality of types may be used in combination. Examples of the tetracarboxylic acid component that provides the repeating unit represented by 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 acids 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 acids may be used alone, or a plurality of types may be used in combination.

In addition, in the polyimide precursor of a more preferable form, the tetracarboxylic acid component (trans-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-) that gives the repeating unit of the chemical formula (1-2) is obtained. Spiro-2″-norbornane-5,5″,6,6″-tetracarboxylic acids and the like) may be used alone, and a tetravalent unit giving the repeating unit of the above chemical formula (1-3) may be used. Carboxylic acid component (cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acids, etc.) One or more of the above may be used, and a tetracarboxylic acid component (trans-endo-endo-norbornane-2-spiro-α-cyclopentanone-α′-, which gives the repeating unit of the chemical formula (1-2), may be used. Spiro-2″-norbornane-5,5″,6,6″-tetracarboxylic acids and the like) and a tetracarboxylic acid component (cis-) that gives the repeating unit of the chemical formula (1-3). endo-endo-norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acids, etc.) May be used.

In the polyimide precursor, the total content of the repeating units represented by the chemical formulas (1-2) and (1-3) is preferably 80 mol% or more based on all repeating units, that is, , At least one type of repeating unit represented by the chemical formula (1-2) and the chemical formula (1-3), the total of the repeating units in all repeating units, preferably 80 mol% or more, more preferably Is preferably 90 mol% or more, more preferably 95 mol% or more, and particularly preferably 99 mol% or more. By containing at least one type of repeating unit represented by the chemical formula (1-2) and the chemical formula (1-3), the total number of the repeating units in all repeating units, preferably by 80 mol% or more, The coefficient of linear thermal expansion of the obtained polyimide becomes small.

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

The diamine component that gives the repeating unit of the chemical formula (1-1) or 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, and When it has a plurality of rings, the aromatic rings are independently linked by a direct bond, an amide bond or an ester bond. The linking position of the aromatic rings is not particularly limited, but a linear structure may be formed by bonding at the 4-position to the amino group or the linking group of the aromatic rings, and the resulting polyimide may have low linear thermal expansion. .. Further, the aromatic ring may be substituted with a methyl group or a trifluoromethyl group. The substitution position is not particularly limited.

The diamine component that gives the repeating unit of the chemical formula (1-1) or 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. Is, 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′-dicarboxylic 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), etc. 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 and biphenyl-4,4'-dicarboxylic acid bis(4-aminophenyl)ester are preferable, p-phenylenediamine, 4,4'-diaminobenzanilide and 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. It should be noted that o-tolidine is not preferred because of its high risk.

As the diamine component that provides 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 provides the repeating unit of the chemical formula (1-A). Other diamines other than the components can be used together. As the other diamine component, other aromatic or aliphatic diamines can be used. 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)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-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, diaminooxybicyclo Heptane, 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'-tetramethyl-1,1'- Examples thereof include spirobiindane and derivatives thereof, and they may be used alone or in combination of two or more.

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

The polyimide precursor of the present invention contains the chemical formula (1-A) in 100 mol% of the diamine component giving A in the chemical formula (1-1) or the chemical formulas (1-2) and (1-3). The ratio of the diamine component giving the structure is preferably 50 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, particularly preferably 100 mol%. % Is preferable. In other words, A is a ratio of one or more kinds of the chemical formula (1-1) in which A is the structure of the chemical formula (1-A), or the repeating units of the chemical formula (1-2) and the chemical formula (1-3). Is, in total, preferably 50 mol% or more, more preferably 70 mol, in all the repeating units represented by the chemical formula (1-1) or the chemical formulas (1-2) and (1-3). % Or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and particularly preferably 100 mol%. When the proportion of the diamine component giving the structure of the chemical formula (1-A) is less than 50 mol %, the coefficient of linear thermal expansion of the obtained polyimide may increase. In one embodiment, from the viewpoint of mechanical properties of the obtained polyimide, 100 mol of a diamine component giving A in the chemical formula (1-1) or the chemical formulas (1-2) and (1-3). %, the total proportion 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%. .. For example, other aromatic or aliphatic diamines such as 4,4′-oxydianiline are added to the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2) and the chemical formula (1-3). It can be used 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 one embodiment, in the polyimide precursor containing a repeating unit represented by the chemical formula (1-1) of the present invention, A is a compound represented by the chemical formula (1-A). It may be preferable to include at least two kinds of repeating units of (1). In one embodiment, in 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, A has the chemical formula ( It may be preferable to include at least two repeating units of the chemical formula (1-2) or the chemical formula (1-2) represented by 1-A). In other words, in the diamine component giving the repeating unit of the chemical formula (1-1), or the diamine component giving the repeating unit of the chemical formulas (1-2) and (1-3), A is the chemical formula ( It may be preferred to include at least two diamine components that give the structure 1-A). A in the chemical formula (1-1), or a diamine component that gives a diamine component giving A in the chemical formulas (1-2) and (1-3) has the structure of the chemical formula (1-A). By containing at least two kinds of components, the high transparency and low linear thermal expansion of the obtained polyimide can be balanced (that is, a polyimide having high transparency and a low linear thermal expansion coefficient can be obtained).

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

In one embodiment, the polyimide precursor of the present invention is
(I) A is m and/or n is 1 to 3, and Z and/or W are each independently -NHCO-, -CONH-, -COO-, or -OCO-. The chemical formula (1-1), which is the structure of the chemical formula (1-A), preferably contains 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 to include at least one repeating unit (II) of the chemical formula (1-1), preferably the chemical formula (1-2) and the chemical formula (1-3), which is the structure of (1-A). There is.

In this embodiment, as the repeating unit (I), for example, A is a repeating unit of the chemical formula (1-1) represented by any one of the following chemical formulas (D-1) to (D-3). A unit is preferable, and A is more preferably a repeating unit of the chemical formula (1-1) represented by any of the following chemical formulas (D-1) to (D-2). The diamine component which gives the repeating unit of the above chemical formula (1-1), in which A is represented by the following chemical formula (D-1) or the following chemical formula (D-2), is 4,4′-diaminobenzanilide. And the diamine component that gives the repeating unit of the chemical formula (1-1) in which A is represented by the chemical formula (D-3) is bis(4-aminophenyl)terephthalate, and these diamines are independent. May be used, or a plurality of types may be used in combination.

In this embodiment, as the repeating unit (II), for example, A is a repeating unit of the chemical formula (1-1) represented by any one of the following chemical formulas (D-4) to (D-6). A unit is preferable, and A is more preferably a repeating unit of the chemical formula (1-1) represented by any of the following chemical formulas (D-4) to (D-5). In addition, the diamine component which gives the repeating unit of said chemical formula (1-1) whose A is represented by the following chemical formula (D-4) is p-phenylenediamine, and A is the following chemical formula (D-5). The diamine component which gives the repeating unit of the chemical formula (1-1) represented 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 above 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 the one or more repeating units (I) is 30 mol% or more and 70 mol% or less in total of all the repeating units represented by the chemical formula (1-1). It is preferable that the proportion of the one or more repeating units (II) is 30 mol% or more and 70 mol% or less in total of all the repeating units represented by the chemical formula (1-1). The total proportion of the unit (I) of 1 or more is 40 mol% or more and 60 mol% or less in all the repeating units represented by the chemical formula (1-1), and 1 or more of the repeating unit (II). It is particularly preferable that the total ratio is 40 mol% or more and 60 mol% or less in all the repeating units represented by the chemical formula (1-1). In one embodiment, the total proportion of the repeating unit (I) is more preferably less than 60 mol%, and preferably 50 mol% or less, in all the repeating units represented by the chemical formula (1-1). Is more preferable, and 40 mol% or less is particularly preferable. Further, in one embodiment, a repeating unit represented by the above chemical formula (1-1) other than the repeating unit (I) and the repeating unit (II) (for example, A has a plurality of aromatic rings). The aromatic rings are linked by an ether bond (-O-)), preferably in an amount of less than 20 mol%, more preferably 10 mol% in all repeating units represented by the chemical formula (1-1). % Or less, particularly preferably less than 10 mol %. Furthermore, in an embodiment, the ratio of the one or more repeating units (I) is 20 mol% or more and 80 mol% or less in total of all the repeating units represented by the chemical formula (1-1). It may be preferable that the ratio of the one or more repeating units (II) is 20 mol% or more and 80 mol% or less in the total of all repeating units represented by the chemical formula (1-1).

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

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

The polyimide precursor of the present invention may include other repeating units other than the repeating units represented by the chemical formula (1-1) or the chemical formulas (1-2) and (1-3). ..

Other aromatic or aliphatic tetracarboxylic acids can be used as the tetracarboxylic acid component that provides another repeating unit. 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'-benzophenonetetracarboxylic 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, sulfonyldiphthalic acid, 1,2,3,4-cyclobutanetetracarboxylic acid , Isopropylidene diphenoxybisphthalic 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(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]decane-3,4,7,8-tetracarboxylic acid, tricyclo[4.2.2.02] ,5]Deca-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-dimethanonaphthalene-2c,3c,6c,7c-tetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t:5c,8c-di Examples thereof include derivatives of methanonaphthalene-2t,3t,6c,7c-tetracarboxylic acid and the like, and acid dianhydrides thereof, which 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 of -2t,3t,6c,7c-tetracarboxylic acid and the like, and acid dianhydrides thereof are more preferable because the polyimide can be easily produced and the resulting polyimide has excellent heat resistance. These acid dianhydrides may be used alone or in combination of two or more.

In the case of a polyimide precursor containing a repeating unit represented by the chemical formula (1-2) and/or the chemical formula (1-3), cis-endo-endo-norbornane- 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-cyclopentanone-α'-spiro-2' It is also possible to use the four stereoisomers of'-norbornane-5,5'',6,6''-tetracarboxylic dianhydride).

The diamine component which gives another repeating unit may be a diamine component which gives the structure of the chemical formula (1-A). In other words, as the diamine component that gives another repeating unit, A is the repeating unit of the chemical formula (1-1), which is the structure of the chemical formula (1-A), or A is the structure of the chemical formula (1-A). The diamine exemplified as the diamine component that gives the repeating unit of the chemical formulas (1-2) and (1-3) 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 that provides the other repeating unit. 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-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclo Hexane, 1,3-diaminocyclobutane, 1,4-bis(aminomethyl)cyclohexane, 1,3-bis(aminomethyl)cyclohexane, diaminobicycloheptane, diaminomethylbicycloheptane, diaminooxybicycloheptane, diaminomethyloxybicyclo Heptane, isophoronediamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis(aminocyclohexyl)methane, bis(aminocyclohexyl)isopropylidene 6,6'-bis(3-aminophenoxy)-3,3,3 ',3'-Tetra Methyl-1,1'-spirobiindane, 6,6'-bis(4-aminophenoxy)-3,3,3',3'-tetramethyl-1,1'-spirobiindane and derivatives thereof, They may be used alone or in combination of two or more.

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 or the like. As described in Non-Patent Document 1, some stereoisomers may be contained depending on the synthesis method. Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acids and the like, or intermediates thereof are purified by a column and the like. By doing so, it is possible to separate the stereoisomers individually or to collect a mixture of several kinds.

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-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acids and the like, or a mixture thereof. Also, regarding norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acids or the like, or an intermediate thereof is used as a column. And the like.

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 as they are as a mixture for polymerization or the like.

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, carbon number 1 to 6, preferably carbon number 1 to 3. Or an alkylsilyl group having 3 to 9 carbon atoms. The types of R ₁ and R ₂ , R ₃ and R ₄ can be changed by the production method described later, and the introduction rate of the functional group can be changed.

When R ₁ and R ₂ , R ₃ and R ₄ are hydrogen, it tends to be easy to produce a polyimide.

When R ₁ and R ₂ , R ₃ and R ₄ are alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, the polyimide precursor tends to have excellent storage stability. In this case, R ₁ and R ₂ , and 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 alkylsilyl groups 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 trimethylsilyl groups or t-butyldimethylsilyl groups.

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, and more preferably 75% or more 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 (R ₁ and R ₂ , at least a part of R ₃ and R ₄ are alkyl groups), 3) 4) Polyamic acid silyl ester (At least a part of R ₁ and R ₂ , R ₃ and R ₄ is an alkylsilyl group) Can be classified into. And the polyimide precursor of this invention can be easily manufactured by the following manufacturing method for every classification. However, the method for producing the polyimide precursor of the present invention is not limited to the following production method.

1) Polyamic Acid In the polyimide precursor of the present invention, the tetracarboxylic acid dianhydride as a tetracarboxylic acid component and the diamine component are substantially equimolar in a solvent, preferably the molar ratio of the diamine component to the tetracarboxylic acid component [diamine The number of moles of component/the 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. By reacting while suppressing the above, a polyimide precursor solution composition can be suitably obtained.

More specifically, but not limited to, diamine is dissolved in an organic solvent, and tetracarboxylic dianhydride is gradually added to the solution while stirring, and the temperature is 0 to 120° C., preferably 5 to 80° C. A polyimide precursor is obtained by stirring in the range of 0 to 72 hours. When the reaction is carried out at 80° C. or higher, the molecular weight fluctuates depending on the temperature history at the time of polymerization, and imidization progresses by heat, so that the polyimide precursor may not be stably manufactured. The addition order of the diamine and the tetracarboxylic dianhydride in the above production method is preferable because the molecular weight of the polyimide precursor is likely to increase. Further, it is possible to reverse the order of addition of the diamine and the tetracarboxylic dianhydride in the above production method, and it is preferable since the precipitate is reduced.

Further, 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 equivalent to the excess molar 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 brought close to the equivalent. The carboxylic acid derivative here does not substantially increase the viscosity of the polyimide precursor solution, that is, a tetracarboxylic acid that does not substantially participate in molecular chain extension, or a tricarboxylic acid that functions as a terminal terminating agent and an anhydride thereof, Dicarboxylic acid and its anhydride are preferable.

2) Polyamic acid ester Tetracarboxylic acid dianhydride is reacted with any alcohol to obtain a diester dicarboxylic acid, and then 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 fluctuates depending on the temperature history at the time of polymerization, and imidization progresses by heat, so that the polyimide precursor may not be stably manufactured. Also, the polyimide precursor can be easily obtained by dehydration condensation of diester dicarboxylic acid and diamine using a phosphorus-based condensing agent or a carbodiimide condensing agent.

Since the polyimide precursor obtained by this method is stable, a solvent such as water or alcohol can be added for purification such as reprecipitation.

3) Polyamic acid silyl ester (indirect method)
In advance, a diamine and a silylating agent are reacted to obtain a silylated diamine. If necessary, the silylated diamine is purified by distillation or the like. Then, the silylated diamine is dissolved in a dehydrated solvent, and tetracarboxylic dianhydride is gradually added to the solution with stirring, and the temperature is 1 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 fluctuates depending on the temperature history at the time of polymerization, and imidization progresses by heat, so that the polyimide precursor may not be stably manufactured.

It is preferable to use a chlorine-free silylating agent as the silylating agent used here because it is not necessary to purify the silylated diamine. Examples of the silylating agent containing no chlorine atom include N,O-bis(trimethylsilyl)trifluoroacetamide, N,O-bis(trimethylsilyl)acetamide, and hexamethyldisilazane. N,O-bis(trimethylsilyl)acetamide and hexamethyldisilazane are particularly preferable because they do not contain a fluorine atom and are low in cost.

Further, in the silylation reaction of diamine, an amine catalyst such as pyridine, piperidine or triethylamine can be used in order to accelerate the reaction. This catalyst can be used as it is as a polymerization catalyst for a polyimide precursor.

4) Polyamic 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 the mixture at 0 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 fluctuates depending on the temperature history at the time of polymerization, and imidization progresses by heat, so that the polyimide precursor may not be stably manufactured.

It is preferable to use a chlorine-free silylating agent as the silylating agent used here because it is not necessary to purify the silylated polyamic acid or the obtained polyimide. Examples of the silylating agent containing no chlorine atom include N,O-bis(trimethylsilyl)trifluoroacetamide, N,O-bis(trimethylsilyl)acetamide, and hexamethyldisilazane. N,O-bis(trimethylsilyl)acetamide and hexamethyldisilazane are particularly preferable because they do not contain a fluorine atom and are low in cost.

Since any of the above production methods can be suitably performed in an organic solvent, as a result, a solution or solution composition containing a polyimide precursor can be easily obtained.

The solvent used in preparing the polyimide precursor is, for example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, or dimethylsulfoxide. And the like, and N,N-dimethylacetamide is particularly preferable, 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 formed are dissolved. The structure is not limited. As the solvent, 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, m-cresol, p-cresol, 3-chlorophenol, phenol such as 4-chlorophenol and the like. A system solvent, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably adopted. In addition, 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 spirits, petroleum A naphtha type solvent or the like can also be used. The solvent may be used in combination of plural kinds.

In the present invention, the logarithmic viscosity of the polyimide precursor is not particularly limited, but the logarithmic viscosity in a 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. It is preferably at least 0.3 dL/g, particularly preferably at least 0.4 dL/g. When the logarithmic viscosity is 0.2 dL/g or more, the polyimide precursor has a high molecular weight, and the resulting polyimide has excellent mechanical strength and heat resistance.

The polyimide precursor composition of the present invention contains a polyimide precursor and an imidazole compound, and may be prepared by adding an imidazole compound to the polyimide precursor solution or solution composition obtained by the above production method. it can. Further, if necessary, the solvent may be removed or added, and desired components other than the imidazole compound may be added. Further, a tetracarboxylic acid component (tetracarboxylic dianhydride, etc.), 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 to give the present invention. It is also possible to obtain the polyimide precursor composition of (a solution composition containing a polyimide precursor and an imidazole compound).

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 the imidazole compound, a polyimide having a small thickness direction retardation can be obtained.

In one embodiment, as the imidazole compound, 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, and particularly preferably 270°C or less. 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 polyimide having higher transparency 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 atm: 205°C), 1-methylimidazole (boiling point at 1 atm: 198°C), 2-methylimidazole (boiling point at 1 atm: 268°C), imidazole (boiling point at 1 atm) : 256° C.) and the like are preferable, and 1,2-dimethylimidazole and 1-methylimidazole are particularly preferable. The imidazole compounds may be used alone or in combination of two or more.

In the present invention, the content of the imidazole compound in the polyimide precursor composition is less than 4 mol per 1 mol of the repeating unit of the polyimide precursor. When the content of the imidazole compound is 4 mol or more per 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 has no problem as long as the polyimide precursor is dissolved, and its structure is not particularly limited. As the solvent, an amide solvent 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 and dimethyl sulfoxide are preferably used. In addition, 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 spirits, petroleum A naphtha type solvent or the like can also be used. Moreover, these can also be used in combination of multiple types. As the solvent for the polyimide precursor composition, the solvent used when preparing the polyimide precursor can be used 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% by mass with respect to the total amount of the solvent, the tetracarboxylic acid component and the diamine component. It is preferable that the proportion is at least mass %. In addition, usually, the total amount of the tetracarboxylic acid component and the diamine component is 60% by mass or less, preferably 50% by mass or less, with respect to the total amount of the solvent, the tetracarboxylic acid component, and the diamine component. It is suitable. This concentration is a concentration that is approximately approximated to the solid content concentration due to the polyimide precursor, but if this concentration is too low, it becomes difficult to control the film thickness of the polyimide film obtained when producing a polyimide film, for example. Sometimes.

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

The polyimide precursor composition of the present invention is, if necessary, a chemical imidizing agent (an acid anhydride such as acetic anhydride or an amine compound such as pyridine or isoquinoline), an antioxidant, a filler (inorganic particles such as silica, etc.). ), a dye, a pigment, a coupling agent such as a silane coupling agent, a primer, a flame retardant, an antifoaming agent, a leveling agent, a rheology control agent (flow aid), and a release agent.

The polyimide of the present invention can be obtained by imidizing the above-described polyimide precursor composition of the present invention (that is, subjecting the polyimide precursor to a dehydration ring closure reaction). The imidization method is not particularly limited, and a known thermal imidization method or chemical imidization method can be suitably applied. Suitable forms of the obtained polyimide include a film, a laminate of a polyimide film and another substrate, a coating film, powder, beads, a molded body, a foamed body, and the like.

In the present invention, the polyimide precursor composition is preferably heat-treated at a maximum heating temperature of higher than 350°C to imidize the polyimide precursor. 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 higher than 350°C, more preferably higher than 380°C, and particularly preferably higher than 400°C, the mechanical properties of the obtained polyimide are improved. To do. The upper limit of the maximum heating temperature of the heat treatment is not particularly limited, but usually 500° C. or lower is preferable.

For example, the polyimide precursor composition of the present invention is cast and coated on a substrate, and the polyimide precursor composition on this substrate has a maximum heating temperature of higher than 350°C, more preferably higher than 380°C, and particularly preferably 400. By heat-treating at a temperature higher than °C to imidize the polyimide precursor, the polyimide can be suitably produced. The heating profile is not particularly limited and may be appropriately selected. However, from the viewpoint of productivity, it is preferable that the heating time is short.

Further, the polyimide precursor composition of the present invention is cast/coated on a substrate, and preferably dried at a temperature range of 180° C. or lower to form a film of the polyimide precursor composition on the substrate, The film of the obtained polyimide precursor composition is peeled off from the substrate, and the maximum heating temperature is higher than 350° C., more preferably higher than 380° C., particularly preferably higher than 400° C. with the end portion of the film fixed. The polyimide can also be suitably produced by heat-treating at a temperature to imidize the polyimide precursor.

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

Polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, the linear thermal expansion coefficient from 150 ℃ to 250 ℃ when formed into a film, preferably 60ppm / K or less, It can be more preferably 50 ppm/K or less, still more preferably 45 ppm/K or less, still more preferably 40 ppm/K or less, and particularly preferably 35 ppm/K or less. If the coefficient of linear thermal expansion is large, the difference in coefficient of linear thermal expansion from the conductor such as metal is large, which may cause problems such as an increase in warpage when forming a circuit board.

The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, but the total light transmittance (average light transmittance at a wavelength of 380 nm to 780 nm) in a film having a thickness of 10 μm is preferably Can 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 such as energy consumption.

In particular, when using a polyimide film such as a display for transmitting light, it is desirable that the polyimide film has high 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 film having a thickness of 10 μm is preferably 75% or more, and preferably 80%. The above can be more preferably more than 80%, further preferably 81% or more, particularly preferably 82% or more.

The film made of the polyimide (polyimide of the present invention) obtained from the polyimide precursor composition of the present invention has a thickness of preferably 0.1 μm to 250 μm, more preferably 1 μm to depending on the use. 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 transmitting light, if the polyimide film is too thick, the light transmittance may decrease.

The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, 1% weight loss temperature is an index of the heat resistance of the polyimide film, preferably 395 ℃ 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 polyimide by forming a transistor on polyimide or the like, if heat resistance is low, swelling may occur between the polyimide and the barrier film due to outgas due to 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, further preferably 700 nm or less. , Particularly preferably 600 nm or less. If the phase difference in the thickness direction is large, problems may occur such that the color of transmitted light is not displayed correctly, color bleeding and the viewing angle are narrowed.

Polyimide obtained from the polyimide precursor composition of the present invention, that is, the polyimide of the present invention has a small retardation in the film thickness direction, has excellent properties such as high transparency, bending resistance, and high heat resistance, and further extremely Since it has a low coefficient of linear thermal expansion, it can be suitably used in applications such as a transparent substrate for displays, a transparent substrate for touch panels, or a substrate for solar cells.

Hereinafter, an example of a method for producing a polyimide film/substrate laminate or a polyimide film using the polyimide precursor composition of the present invention will be described. However, the method is not limited to the following.

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 air, it is dried in a temperature range of 20 to 180° C., preferably 20 to 150° C. by using hot air or infrared rays. Then, the obtained polyimide precursor film on the substrate, or peeled the polyimide precursor film from the substrate, in a state in which the end portion of the film is fixed, in vacuum, in an inert gas such as nitrogen, Alternatively, by using hot air or infrared rays in the air, the polyimide film is heated to imidization at a temperature of, for example, 200 to 500° C., preferably a maximum heating temperature of more than 350° C., more preferably more than 380° C., and particularly preferably more than 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 that the thermal imidization is performed in vacuum or in an inert gas. The thickness of the polyimide film (polyimide film layer in the case of a polyimide film/base material laminate) here is preferably 1 to 250 μm, more preferably 1 to 150 μm, for transportability in the subsequent steps.

In addition, the imidization reaction of the polyimide precursor includes the dehydration cyclization reagent such as acetic anhydride in the presence of a tertiary amine such as pyridine or triethylamine in place of the heat imidization by the heat treatment as described above. It is also possible to perform it by a chemical treatment such as dipping in a solution. Further, by preliminarily introducing and stirring these dehydration cyclization reagents into a polyimide precursor composition (varnish), and casting and drying it on a substrate, a partially imidized polyimide precursor is obtained. It can also be produced, and by further subjecting this to a heat treatment as described above, a polyimide film/base material laminate or a polyimide film can be obtained.

A flexible conductive substrate can be obtained by forming a conductive layer on one side or both sides of the polyimide film/substrate laminate or the polyimide film thus obtained.

The flexible conductive substrate can be obtained, for example, by the following method. That is, the first method is to remove the polyimide film/base material laminate from the base material on the surface of the polyimide film by sputtering, vapor deposition, printing, or the like to form a conductive material (metal or metal oxide). A conductive layer of a conductive layer/a polyimide film/a substrate is manufactured by forming a conductive layer of a conductive material/a conductive organic material, a conductive carbon, or the like). Thereafter, if necessary, the conductive layer/polyimide film laminate is peeled off from the base material to obtain a transparent and flexible conductive substrate composed of the conductive layer/polyimide film laminate.

As a second method, the polyimide film is peeled from the base material of the polyimide film/base material laminate to obtain a polyimide film, and a conductive material (metal or metal oxide, conductive organic material, A conductive layer of (conductive carbon, etc.) is formed in the same manner as in the first method, and the conductive layer/polyimide film laminate, the conductive layer/polyimide film laminate/conductive layer is transparent and has a flexible conductivity. 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 and oxygen by a sputtering, vapor deposition, gel-sol method, or the like, and light adjustment. An inorganic layer such as a layer may be formed.

A circuit is preferably formed in the conductive layer by a method such as 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, with a gas barrier layer or an inorganic layer interposed if necessary. This substrate is flexible, has high transparency, bendability and heat resistance, and has an extremely low coefficient of linear thermal expansion and excellent solvent resistance, so that a fine circuit can be easily formed. Therefore, this substrate can be suitably used as a substrate for a display, a touch panel, or a solar cell.

That is, a flexible thin film transistor is manufactured by further forming a transistor (inorganic transistor, organic transistor) on this substrate by vapor deposition, various printing methods, an inkjet method, or the like, and then a liquid crystal element for display device, EL element, photoelectric device. It is preferably used as an element.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples. The present invention is not limited to the examples below.

In each of the following examples, 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 fluid and uniform state after 3 days, ○,
If cloudy or gelled after 3 days, mark x.

<Evaluation of polyimide film>
[400 nm light transmittance, total light transmittance]
An ultraviolet-visible spectrophotometer/V-650DS (manufactured by JASCO Corporation) was used to measure 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. The measured light transmittance at 400 nm and the light transmittance at 400 nm with a thickness of 10 μm and the total light transmittance were calculated by using the Lambert-Beer equation with the total light transmittance set to 10%. 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 when the reflectance is 10%.
T ₁ ': measured light transmittance at 400 nm (%)
T ₂ : Total light transmittance (%) of a polyimide film having a thickness of 10 μm when the reflectance is 10%
T ₂ ': Measured total light transmittance (%)
L: Thickness of measured polyimide film (μm)

[Elastic modulus, elongation at break]
A polyimide film having a film thickness of about 10 μm was punched out into a dumbbell shape of IEC450 standard to obtain a test piece, and using TENSILON manufactured by ORIENTEC, a chuck gap length of 30 mm, a pulling speed of 2 mm/min, an initial elastic modulus and an elongation at break were measured. It was measured.

[Coefficient of linear thermal expansion (CTE)]
A polyimide film having a film thickness of about 10 μm was cut into a strip shape having a width of 4 mm to obtain a test piece, and using TMA/SS6100 (manufactured by SII Nano Technology Co., Ltd.), a chuck gap length of 15 mm, a load of 2 g, and a heating rate of 20°C The temperature was raised to 500° C. in minutes. The linear thermal expansion coefficient from 150° C. to 250° C. was obtained 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 heating rate of 10° C./min in a nitrogen stream using a calorimeter measuring device (Q5000IR) manufactured by TA Instruments. The 1% weight loss temperature was determined from the obtained weight curve.

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

Abbreviations and purities 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 Product CpODA-cee: cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid di Anhydride CpODA: Mixture of CpODA-tee and CpODA-cee PACDA: N,N'-(1,4-phenylene)bis(1,3-dioxooctahydroisobenzofuran-5-carboxamide)

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

The tetracarboxylic acid components used in Examples and Comparative Examples in Table 1-1, the diamine components used in Examples and Comparative Examples in Table 1-2, and the imidazole/imidazolines used in Examples and Comparative Examples in Table 1-3. The structural formula of the compound is shown.

[Synthesis Example 1]
DABAN 90.91 g (0.4 mol) and PPD 64.88 g (0.6 mol) were placed in a reaction vessel substituted with nitrogen gas, and N-methyl-2-pyrrolidone was charged to the total mass of charged monomers (diamine component and diamine component). 2835.90 g was added in an amount such that the total amount of carboxylic acid components was 16% by mass, and the mixture was 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]
90.91 g (0.4 mol) of DABAN, 54.07 g (0.5 mol) of PPD and 36.84 g (0.1 mol) of BAPB were placed in a reaction vessel substituted with nitrogen gas, and N-methyl-2- Pyrrolidone was added in an amount of 2972.56 g such that the total mass of charged monomers (sum of diamine component and carboxylic acid component) was 16% by mass, and the mixture was 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]
22.73 g (0.100 mol) of DABAN was placed in a reaction vessel purged with nitrogen gas, and N-methyl-2-pyrrolidone was added so that the total mass of charged monomers (the sum of the diamine component and the carboxylic acid component) was 16% by mass. The amount of 3211.16 g was added and the mixture was stirred at room temperature for 1 hour. 38.44 g (0.100 mol) of CpODA was gradually added to this solution. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish C).

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

[Synthesis example 5]
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 in a reaction vessel substituted with nitrogen gas, and N was added. -Methyl-2-pyrrolidone was added in an amount of 294.74 g in which the total mass of charged monomers (sum of diamine component and carboxylic acid component) was 16% by mass, and the mixture was stirred at room temperature for 1 hour. 38.44 g (0.100 mol) of CpODA was gradually added to this solution. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish E).

[Synthesis Example 6]
20.02 g (0.100 mol) of 4,4′-ODA was placed in a reaction vessel substituted with nitrogen gas, and N-methyl-2-pyrrolidone was charged, and the total mass of charged monomers (sum of diamine component and carboxylic acid component) was charged. Of 207.21 g in an amount of 17 mass% was added, and the mixture was stirred at room temperature for 1 hour. 22.41 g (0.100 mmol) of PMDA-HS was gradually added to this solution. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish F).

[Synthesis Example 7]
22.73 g (0.100 mol) of DABAN was placed in a reaction vessel replaced with nitrogen gas, and N-methyl-2-pyrrolidone was added, and the total mass of charged monomers (the sum of the diamine component and the carboxylic acid component) was 20% by mass. The amount of 296.29 g was added, and the mixture was 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]
10.81 g (0.100 mol) of tra-DACH was put into a reaction vessel replaced with nitrogen gas, and N-methyl-2-pyrrolidone was added, and the total mass of charged monomers (total of diamine component and carboxylic acid component) was 12 mass. % Of 2950.64 g was added, and the mixture was stirred at room temperature for 1 hour. 28.69 g (0.0975 mol) of s-BPDA and 0.74 g (0.0025 mol) of a-BPDA were gradually added to this solution. 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 a reaction vessel to obtain a uniform solution. 33.76 g of varnish A obtained in Synthesis Example 1 (10 mmol based on 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 give 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 with a PTFE membrane filter is applied to a glass substrate and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) as it is from room temperature to 410° C. to thermally imidize, and is colorless. A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are shown in Table 2-1.

[Example 2]
0.15 g (1.6 mmol) of 1,2-dimethylimidazole and 0.15 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole was 0.16 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are shown in Table 2-1.

[Example 3]
0.19 g (2.0 mmol) of 1,2-dimethylimidazole and 0.19 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole was 1.0 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 2.0 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are shown in Table 2-1.

[Example 6]
1-Methylimidazole (0.04 g, 0.5 mmol) and N-methyl-2-pyrrolidone (0.04 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 based on 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 give 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 with a PTFE membrane filter is applied to a glass substrate and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) as it is from room temperature to 410° C. to thermally imidize, and is colorless. A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are shown in Table 2-1.

[Example 7]
1-Methylimidazole (0.08 g, 1.0 mmol) and N-methyl-2-pyrrolidone (0.08 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 based on 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 give 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 with a PTFE membrane filter is applied to a glass substrate and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) as it is from room temperature to 410° C. to thermally imidize, and is colorless. A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are shown in Table 2-1.

[Example 8]
0.16 g (2.0 mmol) of 1-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 based on 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 give 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 with a PTFE membrane filter is applied to a glass substrate and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) as it is from room temperature to 410° C. to thermally imidize, and is colorless. A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are shown in Table 2-1.

[Example 9]
0.33 g (4.0 mmol) of 1-methylimidazole and 0.33 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1-methylimidazole was 0.4 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are shown in Table 2-1.

[Example 10]
2-Methylimidazole (0.16 g, 2.0 mmol) and N-methyl-2-pyrrolidone (0.16 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 2-methylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, imidazole was 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 2-phenylimidazole is 0.2 mol based on 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are shown in Table 2-1.

[Example 13]
Benzimidazole (0.24 g, 2.0 mmol) and N-methyl-2-pyrrolidone (0.24 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated 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 with a PTFE membrane filter is applied to a glass substrate and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) as it is from room temperature to 410° C. to thermally imidize, and is colorless. A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are shown in Table 2-1.

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

The results of measuring the properties of this polyimide film are 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole was 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]
0.19 g (2.0 mmol) of 1,2-dimethylimidazole and 0.19 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 based on 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 give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.2 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are 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 the varnish B obtained in Synthesis Example 2 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in the varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to give 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 with a PTFE membrane filter is applied to a glass substrate and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) as it is from room temperature to 410° C. to thermally imidize, and is colorless. A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are 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 the varnish B obtained in Synthesis Example 2 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in the varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.1 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are shown in Table 2-2.

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

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

The results of measuring the properties of this polyimide film are shown in Table 2-2.

Example 17
0.16 g (2.0 mmol) of 1-methylimidazole and 0.16 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 35.39 g of the varnish B obtained in Synthesis Example 2 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in the varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to give 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 with a PTFE membrane filter is applied to a glass substrate and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) as it is from room temperature to 410° C. to thermally imidize, and is colorless. A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are shown in Table 2-2.

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

The results of measuring the properties of this polyimide film are shown in Table 2-2.

[Comparative Example 4]
2-Ethyl-2-imidazoline (0.10 g, 1.0 mmol) and N-methyl-2-pyrrolidone (0.20 g) were added to the reaction vessel to obtain a uniform solution. 35.39 g of the varnish B obtained in Synthesis Example 2 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in the varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to give 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 with a PTFE membrane filter is applied to a glass substrate and heated in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) as it is from room temperature to 410° C. to thermally imidize, and is colorless. A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are 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 based on the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, the varnish gelated. Even if it was stirred at room temperature for 3 hours as it was, a uniform polyimide precursor solution could not be obtained. When calculated from the charged amount, 2-ethyl-2-imidazoline is 0.2 mol based on 1 mol of the repeating unit of the polyimide precursor.

[Comparative Example 6]
2-Ethyl-2-imidazoline 0.49 g (5.0 mmol) and N-methyl-2-pyrrolidone 0.98 g 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 based on the molecular weight of the repeating unit of the polyimide precursor in varnish B) was added to the solution, the varnish gelated. Even if it was stirred at room temperature for 3 hours as it was, a uniform polyimide precursor solution could not be obtained. When calculated from the charged amount, 2-ethyl-2-imidazoline is 0.5 mol per 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 the varnish B obtained in Synthesis Example 2 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in the varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 2-methyl-2-imidazoline is 0.3 mol based on 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are 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 the varnish B obtained in Synthesis Example 2 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in the varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 2-phenylimidazoline is 0.3 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are 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 was added 38.23 g of varnish C obtained in Synthesis Example 3 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in varnish C), and the mixture was stirred at room temperature for 3 hours to give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.1 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

The results of measuring the properties of this polyimide film are 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. 35.99 g of the varnish D obtained in Synthesis Example 4 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in the varnish D) was added to the solution, and the mixture was stirred at room temperature for 3 hours to give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.1 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

The results of measuring the properties of this polyimide film are 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. 35.09 g of the varnish E obtained in Synthesis Example 5 (10 mmol based on the molecular weight of the repeating unit of the polyimide precursor in the varnish E) was added to the solution, and the mixture was stirred at room temperature for 3 hours to give a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, 1,2-dimethylimidazole is 0.1 mol per 1 mol of the repeating unit of the polyimide precursor.

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

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

A polyimide precursor solution filtered with 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. to thermally imidize it, thereby producing colorless A transparent polyimide film/glass laminate was obtained. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a thickness of about 10 μm.

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

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

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

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

The results of measuring the properties of this polyimide film are shown in Table 2-3.

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

The results of measuring the properties of this polyimide film are 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, and Example). 19 and Comparative Example 10, Example 20 and Comparative Example 11, Example 21 and Comparative Example 12, Example 22 and Comparative Example 13, and Example 23 and Comparative Example 14). Further, it can be seen that the transmittance is also improved when 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, or imidazole is used (Examples 1 to 11 and Comparative Example 1, 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, and Example. Example 23 and Comparative Example 14). Further, it can be seen that the storage stability is excellent when the content of the imidazole compound is less than 4 mol per 1 mol of the repeating unit of the polyimide precursor (Examples 1 to 13 and Comparative Example 2). Regarding the mechanical properties, it can be seen that the elongation at break becomes large by setting the maximum heating temperature of the heat treatment for imidization to 350° C. to 410° C. (Example 3 and Reference Example 1). ..

As described above, the polyimide obtained from the polyimide precursor composition of the present invention has a small retardation in the thickness direction, and also has excellent light transmittance, mechanical properties, and a low linear thermal expansion coefficient. INDUSTRIAL APPLICABILITY The polyimide film of the present invention can be suitably used as a transparent substrate which is colorless and transparent and capable of forming fine circuits.

According to the present invention, a polyimide having excellent transparency, in which the thickness direction retardation is smaller even in the same composition, or the thickness direction retardation is small, the transparency is excellent, and the polyimide having excellent mechanical properties is obtained. A polyimide precursor composition (solution composition containing a polyimide precursor) and a method for producing a polyimide can be provided. Polyimide obtained from this polyimide precursor composition has high transparency, and a small thickness direction retardation, and also because it is easy to form a fine circuit with a low linear thermal expansion coefficient, especially for displays, It can be suitably used for forming a substrate for a touch panel, a solar cell or the like.

Claims (10)

A repeating unit represented by the following chemical formula (1) or a polyimide precursor containing a repeating unit represented by the following chemical formula (2),
The imidazole-based compound contains at least one selected from 2-phenylimidazole and benzimidazole ,
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, and have 1 to 6 carbon atoms. 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, and have 1 to 6 carbon atoms. Or an alkylsilyl group having 3 to 9 carbon atoms.) 2. The polyimide precursor composition according to claim 1, wherein the polyimide obtained from this polyimide precursor composition has a light transmittance of 75% or more at a wavelength of 400 nm in a film having a thickness of 10 μm. Content of the said imidazole type compound is 0.05 mol or more and 2 mol or less with respect to 1 mol of repeating units of a polyimide precursor, The polyimide precursor composition of Claim 1 or 2 characterized by the above-mentioned. The polyimide precursor composition according to any one of claims 1 to 3, the heat treatment at the maximum heating temperature 350 ° C. greater than the production method of the polyimide, wherein the imidizing a polyimide precursor. A step of applying a polyimide precursor composition according to the substrate to any one of claims 1 to 3
The polyimide precursor composition on a base material is heat-processed at the maximum heating temperature of more than 350 degreeC, and the process of imidizing a polyimide precursor is included, The manufacturing method of the polyimide of Claim 6 characterized by the above-mentioned. The method for producing a polyimide according to claim 4 or 5 , wherein the maximum heating temperature of the heat treatment exceeds 400°C. A polyimide produced by the method according to claim 4 . The polyimide according to claim 7 , which has a light transmittance of 75% or more at a wavelength of 400 nm in a film having a thickness of 10 μm. A polyimide film produced by the method according to claim 4 . A substrate for a display, a touch panel, or a solar cell, comprising the polyimide according to claim 7 or 8 , or the polyimide film according to claim 9 .