WO2015080156A1

WO2015080156A1 - Polyimide precursor composition, polyimide manufacturing process, polyimide, polyimide film, and base material

Info

Publication number: WO2015080156A1
Application number: PCT/JP2014/081258
Authority: WO
Inventors: 卓也岡; 幸徳小濱; 久野　信治
Original assignee: 宇部興産株式会社
Priority date: 2013-11-27
Filing date: 2014-11-26
Publication date: 2015-06-04
Also published as: TW201529728A

Abstract

The present invention pertains to a polyimide precursor composition which is characterized in that: the composition comprises both a polyimide precursor having a specific composition and an imidazole compound; and the content of the imidazole compound is less than 4mol per mole of the repeating unit of the polyimide precursor.

Description

Polyimide precursor composition, polyimide production method, polyimide, polyimide film, and substrate

The present invention relates to a solution composition (polyimide precursor composition) containing a polyimide precursor that provides a polyimide that is more transparent, has a smaller linear thermal expansion coefficient, and excellent mechanical properties, and a method for producing the polyimide. . The present invention also relates to a polyimide, a polyimide film, and a substrate that are excellent in transparency, have a small linear thermal expansion coefficient, and are excellent in mechanical properties.

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

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

In addition, a method of expressing transparency by using a semi-alicyclic or fully alicyclic polyimide that does not form a charge transfer complex in principle has also been proposed. For example, Patent Documents 1 to 4 disclose various highly translucent semi-alicyclic polyimides using an alicyclic tetracarboxylic dianhydride as a tetracarboxylic acid component and an aromatic diamine as a diamine component. Yes.

Patent Documents 5 and 6 disclose polyimides using decahydro-1,4: 5,8-dimethananaphthalene-2,3,6,7-tetracarboxylic acids as tetracarboxylic acid components. . Non-Patent Document 1 discloses a polyimide using (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethananaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acid as a tetracarboxylic acid component. Non-Patent Document 2 uses (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethananaphthalene-2c, 3c, 6c, 7c-tetracarboxylic acids as the tetracarboxylic acid component. Disclosed polyimide.

However, polyimides with higher transparency are required particularly in the field of display devices and the like. In addition, semi-alicyclic polyimides using alicyclic tetracarboxylic dianhydride as the tetracarboxylic acid component and aromatic diamine as the diamine component have high transparency, bending resistance, and high heat resistance. The linear thermal expansion coefficient tends to be large. If the linear thermal expansion coefficient of polyimide is large and the difference in linear thermal expansion coefficient with a conductor such as metal is large, problems such as increased warping may occur when forming a circuit board, especially for display applications. A fine circuit formation process may not be easy.

On the other hand, Patent Document 7 discloses a polyimide formed by heating a coating liquid obtained by blending a polyimide precursor (polyamic acid) with an imidazoline compound and / or an imidazole compound. More specifically, in Example 1, 2,4-dimethyl was added to a polyamic acid solution obtained from 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride and 4,4′-diaminobiphenyl ether. A solution to which imidazoline has been added is applied onto a substrate and heated at 200 ° C. for 1 hour to obtain an aromatic polyimide film having a thickness of 1000 mm (0.1 μm). In Example 2, a solution obtained by adding 2-ethylimidazoline and 1,2-dimethylimidazole to a solution of polyamic acid obtained from pyromellitic dianhydride and 4,4′-diaminobiphenyl ether was applied onto a substrate. An aromatic polyimide film having a thickness of 800 mm (0.08 μm) is obtained by heating at 150 ° C. for 1 hour. In Patent Document 7, by adding an imidazoline-based compound and / or an imidazole-based compound, the remarkable brown coloration is avoided, and a liquid crystal display element having high light transmittance and excellent transparency can be obtained. It is described. However, the light transmittance at a wavelength of 400 nm of the liquid crystal display element using the polyimide film (liquid crystal alignment film) of Example 1 is 82% (polyimide film thickness: 0.1 μm), and the polyimide film of Example 2 (liquid crystal alignment film). The light transmittance at a wavelength of 400 nm of the liquid crystal display element using the above is 83% (polyimide film thickness: 0.08 μm), and this polyimide does not have sufficient transparency.

In addition, as a method for producing an aromatic polyimide having low transparency, Patent Document 8 discloses that a polyimide precursor resin and a curing accelerator for a 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 onto a substrate, followed by drying and imidization to complete the formation of a polyimide resin layer within a range of 280 to 380 ° C., It is described that the thermal expansion coefficient can be controlled to be low by using these curing accelerators. Patent Document 8 also describes that a curing accelerator having a boiling point exceeding 120 ° C. is preferably used, and that a boiling point not exceeding the upper limit temperature of heat treatment is preferably selected. In addition, it is described that a curing accelerator having a boiling point of, for example, 400 ° C. or higher has a higher ratio of remaining in the polyimide resin layer after imidization and tends to affect the function of the polyimide resin layer.

JP 2003-168800 A International Publication No. 2008/146737 JP 2002-69179 A JP 2002-146021 A JP 2007-2023 A JP-A-6-51316 JP-A 61-267030 JP 2008-115378 A

The present invention has been made in view of the situation as described above, and even a polyimide having the same composition is more transparent and has a low linear thermal expansion coefficient, or is more transparent and has a low linear heat. It aims at providing the manufacturing method of a polyimide precursor composition (solution composition containing a polyimide precursor) from which a polyimide which is an expansion coefficient and was excellent also in mechanical properties is obtained.

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

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

2. Item 2. The polyimide precursor composition according to Item 1, wherein the polyimide precursor contains a repeating unit represented by the following chemical formula (1-2).

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

3. Item 3. The polyimide precursor composition according to Item 1 or 2, wherein A in the chemical formula (1-1) or the chemical formula (1-2) is a group represented by the following chemical formula (1-A): object.

(In the formula, m represents an integer of 0 to 3, and n represents an integer of 0 to 3 independently. Y ₁ , Y ₂ , and Y ₃ are each independently a hydrogen atom, a methyl group, or a trifluoromethyl group. One selected from the group, Q and R are each independently a direct bond, or selected from the group consisting of groups represented by the formula: —NHCO—, —CONH—, —COO—, —OCO— 1 type is shown.)

4). Item 4. The polyimide precursor according to any one of Items 1 to 3, wherein the polyimide obtained from the 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. Composition.
5. Item 5. The polyimide precursor composition according to any one of Items 1 to 4, wherein the content of the imidazole compound is 0.05 mol or more and 2 mol or less with respect to 1 mol of the repeating unit of the polyimide precursor. object.
6). Any one of Items 1 to 5, wherein the imidazole compound is any one of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, and benzimidazole. A polyimide precursor composition according to claim 1.
7). 7. A method for producing a polyimide, wherein the polyimide precursor composition according to any one of items 1 to 6 is heat-treated at a maximum heating temperature exceeding 350 ° C. to imidize the polyimide precursor.
8). Applying the polyimide precursor composition according to any one of Items 1 to 6 on a substrate;
The method for producing polyimide according to Item 7, further comprising a step of heat-treating the polyimide precursor composition on the base material at a maximum heating temperature of over 350 ° C. to imidize the polyimide precursor.
9. Item 9. The method for producing polyimide according to Item 7 or 8, wherein a maximum heating temperature of the heat treatment exceeds 400 ° C.
10. 10. A polyimide produced by the method according to any one of items 7 to 9.
11. Item 11. The polyimide according to Item 10, wherein the light transmittance at a wavelength of 400 nm in a film having a thickness of 10 μm is 75% or more.
12 10. A polyimide film produced by the method according to any one of items 7 to 9.
13. Item 13. A substrate for display, touch panel, or solar cell, comprising the polyimide according to item 10 or 11, or the polyimide film according to item 12.

According to the present invention, a polyimide having the same composition can be a polyimide having a higher transparency and a low linear thermal expansion coefficient, or a polyimide having a higher transparency, a low linear thermal expansion coefficient and excellent mechanical characteristics. The obtained polyimide precursor composition (solution composition containing a polyimide precursor) and a method for producing polyimide can be provided.

The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is highly transparent and has a low linear thermal expansion coefficient, and it is easy to form a fine circuit. It can be suitably used for forming. Moreover, the polyimide of this invention can be used suitably also in order to form the board | substrate for touch panels and a solar cell.

The polyimide precursor composition of the present invention comprises a polyimide precursor containing at least one repeating unit represented by the chemical formula (1-1) and an imidazole compound, and the content of the imidazole compound is determined by the polyimide precursor. Less than 4 moles per mole of repeating units of the body.

A polyimide obtained from a polyimide precursor containing at least one repeating unit represented by the chemical formula (1-1), that is, a semi-alicyclic polyimide, has high transparency. In the case of such a highly transparent polyimide, the use of additives that can cause coloring is not preferred. However, by adding the imidazole compound to the polyimide precursor composition at a ratio of less than 4 mol, preferably 0.05 mol or more and 2 mol or less, with respect to 1 mol of the repeating unit of the polyimide precursor, Transparency is further improved, and the linear thermal expansion coefficient of the resulting polyimide is reduced. That is, according to the present invention, a polyimide having a higher transparency and a lower linear thermal expansion coefficient can be obtained from a polyimide precursor having the same composition.

Furthermore, in order to obtain a highly transparent polyimide, it is generally considered that it is preferable to complete the imidization by heat-treating the polyimide precursor at a relatively low temperature. Even if the polyimide precursor is imidized by heat treatment at a temperature exceeding 350 ° C., particularly preferably exceeding 400 ° C., a highly transparent polyimide can be produced. As a result, the maximum heating temperature of the heat treatment for imidization can be set to a high temperature exceeding 350 ° C., particularly preferably a high temperature exceeding 400 ° C., so that the mechanical properties of the resulting polyimide are improved. That is, according to the present invention, a polyimide having high transparency, a low coefficient of linear thermal expansion, 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 (1-1). As the polyimide precursor, a polyimide precursor containing a repeating unit represented by the chemical formula (1-2) is preferable.

However, in the chemical formula (1-1) and the chemical formula (1-2), one of the acid groups at the 2-position or 3-position of the decahydro-1,4: 5,8-dimethananaphthalene ring reacts with an amino group. An amide bond (—CONH—), _{one of} which is a group represented by —COOX ₁ not forming an amide bond, and one of the acid groups at the 6-position or 7-position reacts with an amino group. The amide bond (—CONH—) is formed, and one of them is a group represented by —COOX ₂ which does not form an amide bond. That is, in the chemical formula (1-1) and the chemical formula (1-2), there are four structural isomers, that is, (i) a group represented by —COOX ₁ at the 2-position and —CONH— at the 3-position. A group represented by —COOX ₂ at the 6-position and a group represented by —CONH—A— at the 7-position; (ii) represented by —COOX ₁ at the 3-position Having a group represented by -CONH- at the 2-position, a group represented by -COOX ₂ at the 6-position, and a group represented by -CONH-A- at the 7-position, iii) a group represented by -COOX ₁ at the 2-position, a group represented by -CONH- at the 3-position, a group represented by -COOX ₂ at the 7-position, and a -CONH-A at the 6-position (Iv) a group represented by —COOX ₁ at the 3-position, a group represented by —CONH— at the 2-position, and —C at the 7-position. All groups represented by OOX ₂ having a group represented by —CONH—A— at the 6-position are included.

In the chemical formula (1-1) and the chemical formula (1-2), A is preferably a divalent group having an aromatic ring having 6 to 40 carbon atoms.

Further, the polyimide precursor includes at least one repeating unit represented by the chemical formula (1-1), more preferably the chemical formula (1-2), in which A is a group represented by the chemical formula (1-A). It is preferable.

In other words, the polyimide precursor is decahydro-1,4: 5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic acid and the like, more preferably (4arH, 8acH) -decahydro-1t, 4t : 5c, 8c-dimethanonaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acids and the like (tetracarboxylic acids and the like are tetracarboxylic acid, tetracarboxylic dianhydride, tetracarboxylic silyl ester, tetracarboxylic acid A tetracarboxylic acid component including a tetracarboxylic acid derivative such as an ester or tetracarboxylic acid chloride) and a diamine component having an aromatic ring, more preferably, A is a group represented by the chemical formula (1-A). Obtained from a diamine component containing a diamine component that gives a repeating unit of formula (1-1) or formula (1-2) It is a polyimide precursor.

Examples of the tetracarboxylic acid component that gives the repeating unit of the chemical formula (1-1) include one type such as decahydro-1,4: 5,8-dimethananaphthalene-2,3,6,7-tetracarboxylic acid. You may use individually and can also be used in combination of multiple types. Examples of the tetracarboxylic acid component that gives the repeating unit of the chemical formula (1-2) include (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethananaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acids Etc., and may be used alone or in combination of two or more.

The diamine component that gives the repeating unit of the chemical formula (1-1) or the chemical formula (1-2) preferably contains a diamine that gives that A is a group represented by the chemical formula (1-A).

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

The diamine component that gives the repeating unit of the chemical formula (1-1) or the chemical formula (1-2) in which A is a group represented by the chemical formula (1-A) is not particularly limited. -Phenylenediamine, m-phenylenediamine, o-tolidine, 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-amino) Benzamide), 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′-diyl bis (4-aminobenzoate) and the like, and may be used alone or in combination of two or more. Among these, p-phenylenediamine, m-tolidine, 4,4′-diaminobenzanilide, 4-aminophenoxy-4-diaminobenzoate, 2,2′-bis (trifluoromethyl) benzidine, benzidine, N, N '-Bis (4-aminophenyl) terephthalamide, biphenyl-4,4'-dicarboxylic acid bis (4-aminophenyl) ester is preferred, p-phenylenediamine, 4,4'-diaminobenzanilide, 2,2' -Bis (trifluoromethyl) benzidine is more preferred. By using p-phenylenediamine, 4,4'-diaminobenzanilide, and 2,2'-bis (trifluoromethyl) benzidine as the diamine component, the resulting polyimide has both high heat resistance and high transmittance. . These diamines may be used alone or in combination of two or more.

The diamine component that gives A in the chemical formula (1-1) or the chemical formula (1-2) (that is, the diamine component that gives the repeating unit of the chemical formula (1-1) or the chemical formula (1-2)) , Other diamines other than the diamine component that gives the structure represented by the chemical formula (1-A) can be used in combination. Other aromatic or aliphatic diamines can be used as other diamine components. For example, 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-amino Phenoxy) 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-a No-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, 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, -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, isophorone diamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis (aminocycloheptane) Xyl) 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′-tetrame Examples include til-1,1′-spirobiindane and derivatives thereof, and these may be used alone or in combination of two or more. Of these, 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 is preferred, and 4,4′-bis (4-aminophenoxy) biphenyl is particularly preferred.

In the polyimide precursor of the present invention, A is a group represented by the chemical formula (1-A) in 100 mol% of the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2). The total proportion of the repeating units represented by the chemical formula (1-1) or the chemical formula (1-2) is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, particularly Preferably it is 100 mol%. When the proportion of the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2) in which A is a group represented by the chemical formula (1-A) is less than 50 mol%, The linear thermal expansion coefficient may increase.

In one embodiment, from the viewpoint of the characteristics of the resulting polyimide, 100 mol% of the diamine component giving the repeating unit of the chemical formula (1-1) or the chemical formula (1-2) has the chemical formula (1-A). It may be preferable that the ratio of the diamine component giving the structure is preferably 70 mol% or less, more preferably 80 mol% or less, and still more preferably 90 mol% or less in total. For example, other diamines such as a diamine having an ether bond (—O—) such as 4,4′-oxydianiline, 4,4′-bis (4-aminophenoxy) biphenyl, and the like are represented by the chemical formula (1- 1) or 100 mol% of the diamine component giving the repeating unit of the chemical formula (1-2), for example, 40 mol% or less, preferably 30 mol% or less, more preferably 20 mol% or less, further preferably 10 mol% or less. It may be preferable to use in

As described above, in the polyimide precursor including the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2) of the present invention, the chemical formula (1-1) or the chemical formula (1-2) A in the formula is preferably the chemical formula (1-A). In other words, in the chemical formula (1-1), the diamine component giving the repeating unit of the chemical formula (1-1) or the chemical formula (1-2) is a group represented by the chemical formula (1-A). Alternatively, a diamine component that gives a repeating unit of the chemical formula (1-2) is preferable. A diamine component that gives A in the chemical formula (1-1) or the chemical formula (1-2) (that is, a diamine component that gives a repeating unit of the chemical formula (1-1) or the chemical formula (1-2)), When A is a diamine component that gives a repeating unit of the chemical formula (1-1) or chemical formula (1-2), which is a group represented by the chemical formula (1-A), the heat resistance of the resulting polyimide is improved. .

In one embodiment, in the polyimide precursor including the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2) of the present invention, A is represented by the chemical formula (1-A). It may be preferable to include at least two repeating units of the chemical formula (1-1) or chemical formula (1-2) as a group. In other words, in the chemical formula (1-1), the diamine component giving the repeating unit of the chemical formula (1-1) or the chemical formula (1-2) is a group represented by the chemical formula (1-A). Alternatively, it may be preferable to include at least two kinds of diamine components that give the repeating unit of the chemical formula (1-2). A diamine component that gives A in the chemical formula (1-1) or the chemical formula (1-2) (that is, a diamine component that gives a repeating unit of the chemical formula (1-1) or the chemical formula (1-2)), By including at least two kinds of diamine components that give the structure represented by the chemical formula (1-A), A can achieve a balance between high transparency and low linear thermal expansion of the resulting polyimide (that is, high transparency). And a polyimide having a low linear thermal expansion coefficient).

In this embodiment, for example, the polyimide precursor containing the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2) of the present invention is represented by the chemical formula (1-1) or the chemical formula ( In 1-2), the diamine component that gives A (that is, the diamine component that gives the repeating unit of the chemical formula (1-1) or the chemical formula (1-2)) is the structure of the chemical formula (1-A). It is preferred that at least two of the diamine components that give are those, one of which is 4,4′-diaminobenzanilide. The diamine component that gives A in the chemical formula (1-1) or the chemical formula (1-2) includes at least two kinds of diamine components that give the structure of the chemical formula (1-A), and one of them is 4, By using 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 represented by the chemical formula (1-1) or the chemical formula (1-2) according to the present invention is represented by the chemical formula (1-1) or the chemical formula (1- 2) The diamine component that gives A (that is, the diamine component that gives the repeating unit of the chemical formula (1-1) or the chemical formula (1-2)) is 2,2′-bis (trifluoromethyl) benzidine and p It preferably contains at least one selected from -phenylenediamine and 4,4'-diaminobenzanilide. By combining these diamine components, a polyimide having both high transparency, low linear thermal expansion and heat resistance can be obtained.

In this embodiment, the diamine component giving A in the chemical formula (1-1) or the chemical formula (1-2) (that is, the repeating unit of the chemical formula (1-1) or the chemical formula (1-2) is substituted. The diamine component to be provided) preferably contains 4,4′-diaminobenzanilide in an amount of 20 mol% to 80 mol%, and includes p-phenylenediamine and 2,2′-bis (trifluoromethyl) benzidine. It is preferable that either one or both contain 20 mol% or more and 80 mol% or less, more preferably 4,4′-diaminobenzanilide is contained 30 mol% or more and 70 mol% or less, and p- Containing 30 mol% or more and 70 mol% or less of either or both of phenylenediamine and 2,2'-bis (trifluoromethyl) benzidine And particularly preferably contains 4,4′-diaminobenzanilide in an amount of 40 mol% to 60 mol%, and either p-phenylenediamine or 2,2′-bis (trifluoromethyl) benzidine. It is more preferable to include 40 mol% or more and 60 mol% or less.

The polyimide precursor of the present invention may contain other repeating units other than the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2).

Other aromatic or aliphatic tetracarboxylic acids can be used as the tetracarboxylic acid component that gives other repeating units. For example, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2 -Dicarboxylic acid, pyromellitic acid, 3,3 ', 4,4'-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, sulfonyldiph Phosphoric acid, 1,2,3,4-cyclobutanetetracarboxylic acid, isopropylidenediphenoxybisphthalic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, [1,1'-bi (cyclohexane)]- 3,3 ′, 4,4′-tetracarboxylic acid, [1,1′-bi (cyclohexane)]-2,3,3 ′, 4′-tetracarboxylic acid, [1,1′-bi (cyclohexane) ] -2,2 ′, 3,3′-tetracarboxylic acid, 4,4′-methylenebis (cyclohexane-1,2-dicarboxylic acid), 4,4 ′-(propane-2,2-diyl) bis (cyclohexane) -1,2-dicarboxylic acid), 4,4'-oxybis (cyclohexane-1,2-dicarboxylic acid), 4,4'-thiobis (cyclohexane-1,2-dicarboxylic acid), 4,4'-sulfonylbis (Sh (Rohexane-1,2-dicarboxylic acid), 4,4 ′-(dimethylsilanediyl) bis (cyclohexane-1,2-dicarboxylic acid), 4,4 ′-(tetrafluoropropane-2,2-diyl) bis ( Cyclohexane-1,2-dicarboxylic acid), octahydropentalene-1,3,4,6-tetracarboxylic acid, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid, 6 -(Carboxymethyl) bicyclo [2.2.1] heptane-2,3,5-tricarboxylic acid, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, bicyclo [2. 2.2] oct-5-ene-2,3,7,8-tetracarboxylic acid, tricyclo [4.2.2.02,5] decane-3,4,7,8-tetracarboxylic acid, tricyclo [ 4.2.2.02 , 5] dec-7-ene-3,4,9,10-tetracarboxylic acid, 9-oxatricyclo [4.2.1.02,5] nonane-3,4,7,8-tetracarboxylic acid 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-Derivatives such as tetracarboxylic acid and their acid dianhydrides may be used, and may be used alone or in combination of two or more. You can also Among these, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, norbornane -2-Spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane 5,5 ″, 6,6 ″ -tetracarboxylic acid, (4arH, 8acH) -decahydro-1t, 4t: 5c , 8c-Dimethananaphthalene-2c, 3c, 6c, 7c-Derivatives such as tetracarboxylic acid and these acid dianhydrides are easy to produce polyimide and are excellent in heat resistance of the resulting polyimide. preferable. These acid dianhydrides may be used alone or in combination of two or more.

The diamine component giving another repeating unit is the diamine exemplified as the diamine component giving the repeating unit of chemical formula (1-1) or chemical formula (1-2), wherein A is a group represented by the chemical formula (1-A). It may be.

Other aromatic or aliphatic diamines can be used as the diamine component that gives other repeating units. For example, 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-amino Phenoxy) 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-a No-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, 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, -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, isophorone diamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis (aminocycloheptane) Xyl) 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′-tetrame Examples include til-1,1′-spirobiindane and derivatives thereof, and these may be used alone or in combination of two or more.

In one embodiment, the polyimide precursor comprises a total of repeating units represented by the chemical formula (1-1) or the chemical formula (1-2), preferably 50 mol% or more in all repeating units. More preferably, it is 70 mol% or more, More preferably, it is 90 mol% or more, Especially preferably, it is preferable to contain 100 mol%. When the ratio of the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2) is 50 mol% or more, the film forming property is improved and the linear thermal expansion coefficient of the resulting polyimide is extremely small. . From the viewpoint of the total light transmittance, the repeating unit represented by the chemical formula (1-1) or the chemical formula (1-2) in the total repeating unit of 100 mol% is preferably from 50 mol% to 99 mol. It can also be used as a mol% or less, more preferably from 60 mol% to 95 mol%, particularly preferably from 70 mol% to 95 mol%.

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 a mixture in polymerization or the like.

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

When X ₁ and X ₂ are hydrogen, they tend preparation of polyimides is easy.

When X ₁ and X ₂ are alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, the storage stability of the polyimide precursor tends to be excellent. In this case, X ₁ and X ₂ are more preferably a methyl group or an ethyl group.

Furthermore, when X ₁ and X ₂ is an alkyl silyl group having 3 to 9 carbon atoms, there is a tendency that the solubility of the polyimide precursor excellent. In this case, X ₁ and X ₂ are more preferably a trimethylsilyl group or a t-butyldimethylsilyl group.

The introduction rate of the functional group is not particularly limited, but when an alkyl group or an alkylsilyl group is introduced, X ₁ and X ₂ are each 25% or more, preferably 50% or more, more preferably 75% or more of the alkyl group. Alternatively, it can be an alkylsilyl group.

The polyimide precursor of the present invention has a chemical structure taken by X ₁ and X ₂ , 1) polyamic acid (X ₁ and X ₂ are hydrogen), 2) polyamic acid ester (at least part of X ₁ and X ₂ is alkyl) Group), 3) and 4) polyamic acid silyl ester (at least a part of X ₁ and X ₂ is an alkylsilyl group). And the polyimide precursor of this invention can be easily manufactured with the following manufacturing methods for every classification. However, the manufacturing method of the polyimide precursor of this invention is not limited to the following manufacturing methods.

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

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

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

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

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

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

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

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

4) Polyamide acid silyl ester (direct method)
A polyimide precursor is obtained by mixing the polyamic acid solution obtained by the method 1) and a silylating agent and stirring 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 varies depending on the temperature history at the time of polymerization, and imidization proceeds due to heat, so there is a possibility that the polyimide precursor cannot be produced stably.

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

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

Solvents used in preparing the polyimide precursor are, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide An aprotic solvent such as N, N-dimethylacetamide is preferred, but any type of solvent can be used without any problem as long as the raw material monomer component and the polyimide precursor to be produced are dissolved. The structure is not limited. As solvents, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α- Cyclic ester solvents such as methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, phenols such as m-cresol, p-cresol, 3-chlorophenol and 4-chlorophenol A system solvent, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably employed. 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, terpene, mineral spirit, petroleum A naphtha solvent can also be used. In addition, a solvent can also be used in combination of multiple types.

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

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

The imidazole compound used in the present invention is not particularly limited as long as it has an imidazole skeleton. By adding an imidazole compound, a polyimide having higher transparency and a lower linear thermal expansion coefficient can 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. An imidazole compound may be used individually by 1 type, and can also be used in combination of multiple types.

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

The polyimide precursor composition of the present invention usually contains a solvent. The solvent used for the polyimide precursor composition of the present invention is not a problem as long as the polyimide precursor is dissolved, and the structure is not particularly limited. As solvents, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone , Cyclic ester solvents such as α-methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol Phenol solvents such as acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably employed. 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, terpene, mineral spirit, petroleum A naphtha solvent can also be used. Moreover, these can also be used combining multiple types. In addition, the solvent used when preparing a polyimide precursor can be used for the solvent of a polyimide precursor composition as it is.

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

In the present invention, the viscosity (rotational viscosity) of the polyimide precursor composition is not particularly limited, but the rotational viscosity measured using 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 to 100 Pa · sec is more preferable. Moreover, thixotropy can also be provided as needed. When the viscosity is in the above range, it is easy to handle when coating or forming a film, and the repelling is suppressed and the leveling property is excellent, so that a good film can be obtained.

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

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

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

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

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

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

The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, but the linear thermal expansion coefficient from 150 ° C. to 250 ° C. when formed into a film is preferably 40 ppm / K or less, More preferably, it is 35 ppm / K or less, More preferably, it is 30 ppm / K or less, Most preferably, it is 25 ppm / K or less. When the linear thermal expansion coefficient is large, the difference in the linear thermal expansion coefficient with a conductor such as metal is large, which may cause problems such as an increase in warpage when a circuit board is formed.

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

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

The film made of the polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) depends on the use, but the thickness of the film is preferably 0.1 μm to 250 μm, more preferably 1 μm to The thickness is 150 μm, more preferably 1 μm to 50 μm, particularly preferably 1 μm to 30 μm. When the polyimide film is used for light transmission, if the polyimide film is too thick, the light transmittance may be lowered.

The polyimide obtained from the polyimide precursor composition of the present invention (polyimide of the present invention) is not particularly limited, but the 1% weight loss temperature, which is an index of heat resistance of the polyimide film, is preferably 470 ° C. or more, more preferably It can be 480 ° C or higher, more preferably 485 ° C or higher, particularly preferably 490 ° C or higher. When a gas barrier film or the like is formed on a polyimide by forming a transistor on the polyimide or the like, if the heat resistance is low, swelling may occur between the polyimide and the barrier film due to outgas accompanying decomposition of the polyimide.

The polyimide obtained from the polyimide precursor composition of the present invention, that is, the polyimide of the present invention has excellent properties such as high transparency, bending resistance and high heat resistance, and also has a very low linear thermal expansion coefficient. In a use of a transparent substrate for a display, a transparent substrate for a touch panel, or a substrate for a solar cell, it can be suitably used.

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, it is not limited to the following method.

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

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

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

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

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

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

Further, the conductive layer is preferably formed with a circuit by a method such as a photolithography method, various printing methods, or an ink jet method.

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 as necessary. This substrate is flexible, has excellent transparency, bendability, and heat resistance, and further has a very low linear thermal expansion coefficient and excellent solvent resistance, so that a fine circuit can be easily formed. Therefore, this board | substrate can be used suitably as a board | substrate for displays, a touch panel, or a solar cell.

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

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

In 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 uniform state with fluidity after 3 days,
If it becomes cloudy or gelled after 3 days, it is marked as x.

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

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

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

[Linear thermal expansion coefficient (CTE)]
A polyimide film having a thickness of about 10 μm is cut into a strip having a width of 4 mm to form a test piece, and TMA / SS6100 (manufactured by SII Nano Technology Co., Ltd.) is used. The length between chucks is 15 mm, the load is 2 g, and the heating rate is 20 ° C. / The temperature was raised to 500 ° C. in minutes. The linear thermal expansion coefficient from 150 ° C. to 250 ° C. was determined from the obtained TMA curve.

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

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

[Diamine component]
DABAN: 4,4′-diaminobenzanilide [Purity: 99.90% (GC analysis)]
PPD: p-phenylenediamine [Purity: 99.9% (GC analysis)]
BAPB: 4,4′-bis (4-aminophenoxy) biphenyl [Purity: 99.93% (HPLC analysis)]
[Tetracarboxylic acid component]
DNDAxx: (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene-2t, 3t, 6c, 7c-tetracarboxylic dianhydride [purity as DNDAxx: 99.2% (GC analysis) ]

[Imidazole-imidazoline compound]
1,2-dimethylimidazole 1-methylimidazole 2-methylimidazole 2-phenylimidazoleimidazolebenzimidazole 2-ethyl-2-imidazoline

[solvent]
NMP: N-methyl-2-pyrrolidone DMAc: N, N-dimethylacetamide

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

[Synthesis Example 1]
In a reaction vessel substituted with nitrogen gas, 11.36 g (0.050 mol) of DABAN and 5.41 g (0.050 mol) of PPD were charged, N-methyl-2-pyrrolidone was charged, and the total mass of monomers (diamine component and 187.999 g of an amount such that the total of the carboxylic acid components was 20% by mass was added and stirred at room temperature for 1 hour. To this solution, 30.23 g (0.100 mol) of DNDAxx 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]
In a reaction vessel substituted with nitrogen gas, 11.36 g (0.050 mol) of DABAN and 5.41 g (0.050 mol) of PPD were charged, N, N-dimethylacetamide was charged, and the total mass of the monomer (diamine component and carbon 187.999 g of an amount such that the total of the acid components was 20% by mass was added and stirred at room temperature for 1 hour. To this solution, 30.23 g (0.100 mol) of DNDAxx was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish B).

[Synthesis Example 3]
In a reaction vessel substituted with nitrogen gas, 6.82 g (0.030 mol) of DABAN, 4.33 g (0.040 mol) of PPD, and 11.05 g (0.030 mol) of BAPB were placed, and N-methyl-2- Pyrrolidone was added in an amount of 209.70 g so that the total monomer weight (total of diamine component and carboxylic acid component) was 20% by mass, and the mixture was stirred at room temperature for 1 hour. To this solution, 30.23 g (0.100 mol) of DNDAxx was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish C).

[Synthesis Example 4]
In a reaction vessel substituted with nitrogen gas, 15.91 g (0.070 mol) of DABAN and 11.05 g (0.030 mol) of BAPB were charged, N-methyl-2-pyrrolidone was charged, and the total mass of monomers (diamine component and 228.76 g in such an amount that the total amount of carboxylic acid components was 20% by mass was added and stirred at room temperature for 1 hour. To this solution, 30.23 g (0.100 mol) of DNDAxx was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish D).

[Synthesis Example 5]
In a reaction vessel purged with nitrogen gas, 9.09 g (0.040 mol) of DABAN, 4.33 g (0.040 mol) of PPD, and 7.37 g (0.020 mol) of BAPB were placed, and N-methyl-2- Pyrrolidone was added in an amount of 204.06 g so that the total monomer weight (total of diamine component and carboxylic acid component) was 20% by mass, and the mixture was stirred at room temperature for 1 hour. To this solution, 30.23 g (0.100 mol) of DNDAxx was gradually added. The mixture was stirred at room temperature for 12 hours to obtain a uniform and viscous polyimide precursor solution (varnish E).

[Example 1]
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. 23.50 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole per mole of the repeating unit of the polyimide precursor is 0.1 equivalent.

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 440 ° C. on the glass substrate to thermally imidize it. A transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

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

[Example 2]
1,8-dimethylimidazole (0.38 g, 4.0 mmol) and N-methyl-2-pyrrolidone (0.38 g) were added to the reaction vessel to obtain a uniform solution. 23.50 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole per 0.4 mole of the repeating unit of the polyimide precursor is 0.4 equivalent.

Example 3
0.96 g (10.0 mmol) of 1,2-dimethylimidazole and 0.48 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 23.50 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole per 1.0 mole of the repeating unit of the polyimide precursor is 1.0 equivalent.

Example 4
1.92 g (20.0 mmol) of 1,2-dimethylimidazole and 0.48 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 23.50 g of varnish A obtained in Synthesis Example 1 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish A) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole per 2.0 moles of repeating units of the polyimide precursor is 2.0 equivalents.

[Comparative Example 1]
Varnish A obtained in Synthesis Example 1 filtered through a PTFE membrane filter was applied to a glass substrate and heated from room temperature to 440 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

Example 5
0.10 g (1.0 mmol) of 1,2-dimethylimidazole and 0.10 g of N, N-dimethylacetamide were added to the reaction vessel to obtain a uniform solution. 23.50 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the polyimide precursor repeating unit in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole per mole of the repeating unit of the polyimide precursor is 0.1 equivalent.

Example 6
A uniform solution was obtained by adding 0.38 g (4.0 mmol) of 1,2-dimethylimidazole and 0.38 g of N, N-dimethylacetamide to the reaction vessel. 23.50 g of varnish B obtained in Synthesis Example 2 (10 mmol with respect to the molecular weight of the polyimide precursor repeating unit in varnish B) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole per 0.4 mole of the repeating unit of the polyimide precursor is 0.4 equivalent.

[Comparative Example 2]
Varnish B obtained in Synthesis Example 2 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 440 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

Example 7
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, 26.21 g of varnish C obtained in Synthesis Example 3 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish C) was added and stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole relative to 1 mole of the repeating unit of the polyimide precursor is 0.2 equivalent.

[Comparative Example 3]
Varnish C obtained in Synthesis Example 3 filtered through a PTFE membrane filter was applied to a glass substrate and heated from room temperature to 440 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

Example 8
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. 28.60 g of varnish D obtained in Synthesis Example 4 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish D) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole relative to 1 mole of the repeating unit of the polyimide precursor is 0.2 equivalent.

[Comparative Example 4]
Varnish D obtained in Synthesis Example 4 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 440 ° C. as it was on a glass substrate in a nitrogen atmosphere (oxygen concentration 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

Example 9
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. 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole relative to 1 mole of the repeating unit of the polyimide precursor is 0.2 equivalent.

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

Example 10
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. 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1-methylimidazole per 0.2 mole of the repeating unit of the polyimide precursor is 0.2 equivalent.

Example 11
0.16 g (2.0 mmol) of 2-methylimidazole and 0.16 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 2-methylimidazole relative to 1 mole of the repeating unit of the polyimide precursor is 0.2 equivalent.

Example 12
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. 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of imidazole relative to 1 mole of the repeating unit of the polyimide precursor is 0.2 equivalent.

Example 13
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. 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 2-phenylimidazole per 0.2 mole of the repeating unit of the polyimide precursor is 0.2 equivalent.

Example 14
A uniform solution was obtained by adding 0.24 g (2.0 mmol) of benzimidazole and 0.24 g of N-methyl-2-pyrrolidone to the reaction vessel. 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of benzimidazole per 0.2 mol of the repeating unit of the polyimide precursor is 0.2 equivalent.

[Comparative Example 5]
Varnish E obtained in Synthesis Example 5 filtered through a PTFE membrane filter was applied to a glass substrate, and heated from room temperature to 440 ° C. on a glass substrate in a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to thermally imidize. A colorless transparent polyimide film / glass laminate was obtained. Next, the obtained polyimide film / glass laminate was immersed in water and then peeled off and dried to obtain a polyimide film having a film thickness of about 10 μm.

[Comparative Example 6]
0.10 g (1.0 mmol) of 2-ethyl-2-imidazoline and 0.90 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. When 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol relative to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, the varnish gelled. Even if it was stirred at room temperature for 3 hours, a uniform polyimide precursor solution could not be obtained. When calculated from the charged amount, the number of moles of 2-ethyl-2-imidazoline per mole of the repeating unit of the polyimide precursor is 0.1 equivalent.

[Comparative Example 7]
0.20 g (2.0 mmol) of 2-ethyl-2-imidazoline and 1.80 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. When 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol relative to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, the varnish gelled. Even if it was stirred at room temperature for 3 hours, a uniform polyimide precursor solution could not be obtained. When calculated from the charged amount, the number of moles of 2-ethyl-2-imidazoline per 0.2 mole of the repeating unit of the polyimide precursor is 0.2 equivalent.

[Comparative Example 8]
1.85 g (40.0 mmol) of 1,2-dimethylimidazole and 0.50 g of N-methyl-2-pyrrolidone were added to the reaction vessel to obtain a uniform solution. 25.51 g of varnish E obtained in Synthesis Example 5 (10 mmol with respect to the molecular weight of the repeating unit of the polyimide precursor in varnish E) was added to the solution, and the mixture was stirred at room temperature for 3 hours to obtain a uniform and viscous polyimide. A precursor solution was obtained. When calculated from the charged amount, the number of moles of 1,2-dimethylimidazole per 4.0 moles of repeating units of the polyimide precursor is 4.0 equivalents. When the obtained polyimide precursor solution was stored at 23 ° C., the polyimide precursor solution gelled by the third day.

From the results shown in Tables 2-1 and 2-2, it can be seen that the polyimide obtained from the polyimide precursor composition containing the imidazole compound is superior in transparency and has a small linear thermal expansion coefficient (Example 1). To 4 and Comparative Example 1, Examples 5 to 6 and Comparative Example 2, Example 7 and Comparative Example 3, Example 8 and Comparative Example 4, Examples 9 to 14 and Comparative Example 5). Moreover, it turns out that it is excellent also in storage stability as content of an imidazole type compound is less than 4 mol with respect to 1 mol of repeating units of a polyimide precursor (Example 9 and Comparative Example 8).

As described above, the polyimide obtained from the polyimide precursor composition of the present invention has excellent light transmittance and mechanical properties, and also has a low linear thermal expansion coefficient. It can be suitably used as a transparent substrate capable of forming a colorless and transparent and fine circuit for display applications and the like.

According to the present invention, even a polyimide having the same composition is superior in transparency and has a low linear thermal expansion coefficient, or more transparent, has a low linear thermal expansion coefficient, and has excellent mechanical properties. Can be provided, and a polyimide precursor composition (solution composition containing a polyimide precursor) and a method for producing polyimide can be provided. The polyimide obtained from this polyimide precursor composition is highly transparent and has a low linear thermal expansion coefficient, so that it is easy to form a fine circuit. It can be suitably used to form.

Claims

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

(In the formula, A is a divalent group having an aromatic ring, and X 1 and X 2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms. .)
The polyimide precursor composition according to claim 1, wherein the polyimide precursor includes a repeating unit represented by the following chemical formula (1-2).

(In the formula, A is a divalent group having an aromatic ring, and X 1 and X 2 are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms. .)
The polyimide precursor composition according to claim 1 or 2, wherein A in the chemical formula (1-1) or the chemical formula (1-2) is a group represented by the following chemical formula (1-A). object.

(In the formula, m represents an integer of 0 to 3, and n represents an integer of 0 to 3 independently. Y 1 , Y 2 , and Y 3 are each independently a hydrogen atom, a methyl group, or a trifluoromethyl group. One selected from the group, Q and R are each independently a direct bond, or selected from the group consisting of groups represented by the formula: —NHCO—, —CONH—, —COO—, —OCO— 1 type is shown.)
The polyimide precursor according to any one of claims 1 to 3, wherein the polyimide obtained from the polyimide precursor composition has a light transmittance at a wavelength of 400 nm of a film having a thickness of 10 µm of 75% or more. Composition.
5. The polyimide precursor composition according to claim 1, wherein the content of the imidazole compound is 0.05 mol or more and 2 mol or less with respect to 1 mol of the repeating unit of the polyimide precursor. object.
6. The imidazole compound is any one of 1,2-dimethylimidazole, 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, imidazole, and benzimidazole. A polyimide precursor composition according to claim 1.
A method for producing a polyimide, characterized in that the polyimide precursor composition according to any one of claims 1 to 6 is heat-treated at a maximum heating temperature exceeding 350 ° C to imidize the polyimide precursor.
Applying the polyimide precursor composition according to any one of claims 1 to 6 on a substrate;
The method for producing a polyimide according to claim 7, further comprising a step of heat-treating the polyimide precursor composition on the substrate at a maximum heating temperature exceeding 350 ° C. to imidize the polyimide precursor.
The method for producing polyimide according to claim 7 or 8, wherein a maximum heating temperature of the heat treatment exceeds 400 ° C.
A polyimide produced by the method according to any one of claims 7 to 9.
The polyimide according to claim 10, wherein a light transmittance at a wavelength of 400 nm in a film having a thickness of 10 μm is 75% or more.
A polyimide film produced by the method according to any one of claims 7 to 9.
A substrate for a display, a touch panel, or a solar cell, comprising the polyimide according to claim 10 or 11, or the polyimide film according to claim 12.