TWI834630B - Polyimide, polyimide solution composition, polyimide film, and substrate - Google Patents

Abstract

The present invention provides a polyimide, which is a polyimide containing more than 50 mol % of the repeating units represented by the following chemical formula (1) relative to all repeating units, when measured with a film having a thickness of 10 μm. In this case, the linear thermal expansion coefficient between 100 and 250°C is less than 25ppm/K, and the light transmittance at a wavelength of 400nm is more than 80%.

Description

Polyimide, polyimide solution composition, polyimide film and base containing the same Material layer body, substrate, display, and manufacturing method thereof

The present invention relates to a polyimide with high transparency and extremely low linear thermal expansion coefficient, and a polyimide solution composition that can obtain a polyimide with high transparency and extremely low linear thermal expansion coefficient. Furthermore, the present invention also relates to a polyimide film and a substrate.

In recent years, with the advent of a highly information-based society, there has been progress in the development of optical materials such as liquid crystal alignment films or protective films for color filters in display devices such as optical fibers or optical waveguides in the field of optical communications. Especially in the field of display devices, some people have been exploring the use of lightweight and highly flexible plastic substrates to replace glass substrates, or actively developing bendable and roundable displays. Therefore, higher performance optical materials that can be used in such applications are sought.

Aromatic polyimide is inherently colored yellowish brown due to the formation of intramolecular conjugation or charge transfer complexes. As methods for suppressing coloration, it has been proposed to introduce fluorine atoms into the molecule, impart flexibility to the main chain, introduce bulky groups as side chains, etc., in order to prevent the formation of intramolecular conjugation or charge transfer complexes. Ways to demonstrate transparency.

In addition, a method of exhibiting transparency by using a semi-alicyclic or fully alicyclic polyimide that theoretically does not form a charge transfer complex has also been proposed. In particular, many high-permeability products using aromatic tetracarboxylic dianhydride as the tetracarboxylic acid component and alicyclic diamine as the diamine component have been proposed. Clear semi-alicyclic polyimide and highly transparent semi-alicyclic polyimide using alicyclic tetracarboxylic dianhydride as the tetracarboxylic acid component and aromatic diamine as the diamine component.

For example, Patent Document 1 discloses a polyimide using norbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornane-5,5”,6,6” -Tetracarboxylic dianhydride (abbreviation: CpODA) uses 2,2'-bis(trifluoromethyl)benzidine (abbreviation: TFMB) as the tetracarboxylic acid component, or TFMB and other aromatic diamines (for example, TFMB: 4,4'-diamine benzamide: 9,9-bis(4-aminophenyl)fluorine=5:4:1 (molar ratio)) as the diamine component. Disclosed in Patent Document 2 A polyimide in which CpODA with a specific stereoisomer ratio is used as the tetracarboxylic acid component, and TFMB and other aromatic diamines (for example, TFMB: 4,4'-diamine benzyl aniline = 5 : 5 (molar ratio), etc.) as the diamine component. However, in the examples of Patent Document 1 and Patent Document 2, polyimide obtained from CpODA and a diamine component containing 50 mol% or more of TFMB Although it has high transparency, it tends to have a large linear thermal expansion coefficient. If the linear thermal expansion coefficient of polyimide is large and the difference between the linear thermal expansion coefficient of polyimide and the linear thermal expansion coefficient of a conductor such as metal is large, warpage may occur when forming a circuit board. , it may be particularly difficult to form precision circuits for display applications, etc.

On the other hand, Patent Document 3 discloses a polyimide precursor, which is produced by thermal imidization of a tetracarboxylic acid component and a diamine component containing a specific aromatic diamine. The conversion rate is above 30% and below 90%. More specifically, in the example of Patent Document 3, a polyimide precursor with an imidization rate of 33 to 60% is produced, which uses CpODA as the tetracarboxylic acid component, and uses TFMB and other aromatic diamines. (For example, TFMB: 4,4'-diamine benzyl aniline = 5:5 (molar ratio), etc.) as the diamine component. Regarding the imidization rate, Patent Document 3 describes that a polyimide precursor having an imidization rate of 30% or more is imidized to produce a polyimide. When 0% polyimide precursor is imidized, the linear thermal expansion coefficient can be obtained For low polyimide, on the other hand, if the imidization rate exceeds 90%, the solubility of the polyimide precursor (or polyimide) decreases, and the polyimide precursor (or polyimide) imine) precipitates, and polyimide with excellent characteristics may not be obtained.

Furthermore, Patent Document 4 discloses a polyimide resin, which is a polyimide resin containing a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine compound, wherein the structural unit A Contains a structural unit (A-1) derived from CpODA, a structural unit (A-2) derived from pyromellitic dianhydride, and a structural unit derived from 1,2,4,5-cyclohexanetetracarboxylic dianhydride. At least one of the structural units (A-3). The structural unit B includes the structural unit (B-1) derived from 9,9-bis(4-aminophenyl)fluoride. In the structural unit B, the structural unit The proportion of (B-1) is 60 mol% or more. More specifically, in Example 4 of Patent Document 4, a polyimide resin is produced from CpODA (A-1) and 9,9-bis(4-aminophenyl)fluoride (B-1). In Example 5 of Patent Document 4, CpODA (A-1), 1,2,4,5-cyclohexanetetracarboxylic dianhydride (A-3) and 9,9-bis(4-amino Phenyl) fluorine (B-1) is used to produce polyimide resin ((A-1): (A-3)=1:1 (mol ratio)). In Example 6 of Patent Document 4, CpODA (A-1), 9,9-bis(4-aminophenyl)quinone (B-1) and 2,2'-dimethylbenzidine (B- 2) Manufacture of polyimide resin ((B-1): (B-2)=4:1 (mol ratio)). In the examples of Patent Document 4, after obtaining the polyimide resin solution, the polyimide resin solution is coated on the substrate, and the solvent is removed by drying to obtain a polyimide film.

Furthermore, Example 1 and Comparative Example 1 of Patent Document 5 describe a product composed of CpODA and 4,4'-diamino-2,2'-dimethylbiphenyl and 9,9-bis(4-amino). Phenyl) fluoride (molar ratio: 1/1), and polyamide imide obtained from CpODA and 9,9-bis(4-aminophenyl) fluoride. In Example 1 and Comparative Example 1 of Patent Document 5, a polyimide film is obtained by coating the polyimide solution on a substrate after obtaining a polyimide solution, and then hardening the coating film. .

[Prior technical literature]

[Patent Document]

[Patent Document 1] International Publication No. 2013/179727

[Patent Document 2] International Publication No. 2014/046064

[Patent Document 3] International Publication No. 2014/208704

[Patent Document 4] International Publication No. 2017/191822

[Patent Document 5] Japanese Patent Application Publication No. 2017-133027

The object of the present invention is to provide a polyimide that achieves both high transparency and low linear thermal expansion at a high level, that is, a polyimide with high transparency and extremely low linear thermal expansion coefficient, and to provide a polyimide with the properties of Polyimide solution composition of polyimide with high transparency and extremely low linear thermal expansion coefficient.

The present invention relates to the following.

1. A polyimide, which contains a polyimide having a repeating unit represented by the following chemical formula (1) in an amount of more than 50 mol % relative to all repeating units, characterized in that it is processed with a film having a thickness of 10 μm In the case of measurement, the linear thermal expansion coefficient between 100 and 250°C is less than 25 ppm/K, and the light transmittance at a wavelength of 400 nm is more than 80%.

[Chemical 1]

2. A polyimide solution composition, characterized in that the following polyimide is dissolved in a solvent: the polyimide contains repeating units represented by the following chemical formula (1) relative to all repeating units: More than 50 mol%, and the imidization rate exceeds 90%.

3. A polyimide obtained by removing the solvent from the polyimide solution composition of item 2.

4. A polyimide film obtained by removing the solvent from the polyimide solution composition of item 2.

5. For example, the polyimide film in item 3 or the polyimide film in item 4 is characterized by: when measured with a film thickness of 10 μm, the linear thermal expansion coefficient between 100 and 250°C is: Below 25ppm/K, and the light transmittance at wavelength 400nm is above 80%.

6. A laminate characterized by forming a film containing the polyimide of the 1st item or the polyimide film of the 4th or 5th item on a glass base material.

7. A substrate for a display, a touch screen or a solar cell, characterized by comprising the polyimide of item 1 or 3 or the polyimide film of item 4 or 5 .

8. A method for manufacturing a polyimide film/substrate laminate, comprising: applying the polyimide solution composition of item 2 to a substrate; and applying the polyimide on the substrate. The step of heating the solution composition.

9. A method for manufacturing a polyimide film, comprising: applying the polyimide solution composition of item 2 to a base material; and heating the polyimide solution composition on the base material. ; and the step of peeling off the polyimide film formed on the base material from the base material.

10. A method for manufacturing a polyimide film, comprising: applying the polyimide solution composition of item 2 to a substrate; and drying the polyimide solution composition to obtain self-supporting properties. The step of forming a film; and the steps of peeling the self-supporting film from the substrate and heating it.

According to the present invention, it is possible to provide a polyimide that achieves both high transparency and low linear thermal expansion at a high level, that is, a polyimide with high transparency and extremely low linear thermal expansion coefficient. Furthermore, according to the present invention, it is possible to provide a polyimide solution composition capable of obtaining a polyimide having high transparency and extremely low linear thermal expansion coefficient.

The polyimide of the present invention and the polyimide obtained from the polyimide solution composition of the invention have high transparency and extremely low linear thermal expansion coefficient, and can easily form precise electrical components. path, and can be preferably used to form a substrate for display applications, etc. In addition, the polyimide of the present invention and the polyimide obtained from the polyimide solution composition of the present invention can also be preferably used to form substrates for touch screens and solar cells.

In this manual, the following abbreviations are used appropriately.

CpODA: norbornane-2-spiro-α-cyclopentanone-α’-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic dianhydride

CpODA, etc.: Norbornane-2-spiro-α-cyclopentanone-α’-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acids, etc. (tetracarboxylic acids, etc. refer to tetracarboxylic acid derivatives such as tetracarboxylic dianhydride, tetracarboxylic acid silyl ester, tetracarboxylic acid ester, and tetracarboxylic acid acyl chloride)

TFMB: 2,2’-bis(trifluoromethyl)benzidine

The tetracarboxylic acid component that provides the repeating unit represented by the chemical formula (1) is CpODA, etc., and the diamine component that provides the repeating unit represented by the chemical formula (1) is TFMB.

The polyimide according to the first embodiment of the present invention contains the repeating unit represented by the chemical formula (1) in an amount of more than 50 mol% relative to all repeating units. When measured with a film with a thickness of 10 μm, The linear thermal expansion coefficient between 100~250℃ is less than 25ppm/K, and the light transmittance at a wavelength of 400nm is more than 80%. When measured with a film with a thickness of 10 μm, the linear thermal expansion coefficient between 100 and 250°C is preferably 20 ppm/K or less, more preferably 15 ppm/K or less. Moreover, when measured with a film having a thickness of 10 μm, the light transmittance at a wavelength of 400 nm is preferably 83% or more.

It has been known conventionally that a polyimide obtained from a tetracarboxylic acid component mainly containing CpODA and the like and a diamine component mainly containing TFMB suppresses imidization of the tetracarboxylic acid component in a solvent at a relatively low temperature. After reacting with the diamine component to obtain a solution containing a polyimide precursor such as polyamide acid, the polyimide precursor solution is applied to the substrate, heated to remove (dry) the solvent, and then Amination, whereby it is manufactured. The polyimide thus obtained has high transparency as mentioned above, but its linear thermal expansion coefficient tends to be large. On the other hand, in the present invention, a tetracarboxylic acid component mainly containing CpODA and the like and a diamine component mainly containing TFMB are reacted in a solvent under conditions under which the imidization reaction proceeds, to obtain an imidization rate exceeding After preparing a solution (or solution composition) of soluble polyimide with an imidization rate of 90%, preferably 95% or more, the solvent is removed from the polyimide solution (or solution composition) to produce a polyimide. acyl imine. If polyimide is produced using this method, the linear thermal expansion coefficient can be significantly reduced compared to conventional methods while maintaining high transparency. Judging from the results, it is possible to simultaneously achieve high transparency and low linear thermal expansion at a high level, thereby obtaining a polyimide with high transparency and extremely low linear thermal expansion coefficient.

In the polyimide according to the first embodiment of the present invention, the content of the repeating unit represented by the chemical formula (1) derived from CpODA and the like and TFMB is more than 50 mol%, such as 80 mol%, relative to all repeating units. It can be more than 100 mol%, further more than 90 mol%, and still further can be 100 mol%.

The polyimide solution composition of the second embodiment of the present invention is a solution composition in which the following polyimide is dissolved in a solvent; the polyimide contains the repeating unit represented by the chemical formula (1) , more than 50 mol% relative to all repeating units, and the imidization rate exceeds 90%, relatively Preferably, the acyl imidization rate is above 95%. By removing the solvent from the polyimide solution composition, a polyimide with high transparency and extremely low linear thermal expansion coefficient can be obtained, for example, when the film thickness is measured at 10 μm, between 100 and 250°C The linear thermal expansion coefficient is 25 ppm/K or less, preferably 20 ppm/K or less, more preferably 15 ppm/K or less, and the light transmittance at a wavelength of 400 nm is 80% or more, preferably 83% or more.

Here, if the imidization rate is low, for example, if the imidization rate is about 30% to 80%, although it is also related to the composition of the polyimide, atomization may occur, resulting in the resulting polyimide Transparency is reduced. In particular, in the case of polyimide composed of the repeating unit of the chemical formula (1) [polyimide obtained from CpODA, etc. and TFMB], the haze tends to increase easily.

In the polyimide solution composition of the second embodiment of the present invention, the content of the repeating unit represented by the chemical formula (1) derived from CpODA, etc. and TFMB, relative to all repeating units, is It exceeds 50 mol%, for example, it is more than 80 mol%, further it is more than 90 mol%, and it may further be 100 mol%.

Here, the acyl imidization rate can be measured by the ratio of "the repeating units of the acyl imine structure" to the "total amount of the repeating units of the amide acid structure and the repeating units of the acyl imine structure". The ¹ H-NMR spectrum of an amine (polyimide solution composition) is calculated from the ratio of the integrated value of the aromatic proton peak (6.2~8.5ppm) to the integrated value of the amide proton peak (9.5~11.0ppm) .

The polyimide in the polyimide solution composition according to the first embodiment of the present invention and the polyimide solution composition according to the second embodiment of the invention contains the repeating unit represented by the chemical formula (1). The polyimide is more than 50 mol% based on all repeating units, and is obtained from a tetracarboxylic acid component including CpODA and the like and a diamine component including TFMB.

CpODA and the like as the tetracarboxylic acid component used here preferably include trans-endo-endo-norbornan-2-spiro-α-cyclopentanone-α'- among the six stereoisomers. Spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acids (trans-endo-endosome) and/or cis-endo-norbornane-2-spiro-α- Cyclopentanone-α'-spiro-2"-norbornane-5,5",6,6"-tetracarboxylic acids, etc. (cis-endosome). In one embodiment, the total proportion of trans-endo-endosomes and/or cis-endo-endosomes in CpODA and the like is preferably 80 mol% or more, more preferably 90 mol% or more, and still more preferably It is more than 95 mol%, and the best one is more than 99 mol%.

CpODA and others can be used alone or in combination.

Among the polyimide in the polyimide solution composition of the first embodiment of the invention and the polyimide solution composition of the second embodiment of the invention, in addition to the repeating unit represented by the chemical formula (1) In addition, one or more types of other repeating units may be included in a range of 50 mol% or less based on all the repeating units.

As the tetracarboxylic acid component that provides other repeating units, any other aromatic or aliphatic tetracarboxylic acids other than CpODA and the like can be used. Examples include: 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane, 4-(2,5-dilateral oxytetrahydrofuran-3-yl)-1,2,3,4- Tetralin-1,2-dicarboxylic acid, pyromellitic acid, 3,3',4,4'-benzophenone tetracarboxylic acid, 3,3',4,4'-biphenyl tetracarboxylic acid , 2,3,3',4'-biphenyltetracarboxylic acid, 4,4'-oxydiphthalic acid, bis(3,4-dicarboxyphenyl)teredicanhydride, m-triphenyl- 3,4,3',4'-tetracarboxylic dianhydride, p-triphenyl-3,4,3',4'-tetracarboxylic dianhydride, biscarboxyphenyldimethylsilane, bis-dicarboxybenzene Oxydiphenyl sulfide, sulfonyl diphthalic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, isopropylidene diphenoxydiphthalic acid, cyclohexane-1 ,2,4,5-tetracarboxylic acid, [1,1'-bis(cyclohexane)]-3,3',4,4'-tetracarboxylic acid, [1,1'-bis(cyclohexane) )]-2,3,3',4'-tetracarboxylic acid, [1,1'-bis(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), octahydropentene-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-tri Carboxylic 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, tricyclic [4.2.2.02,5]Decan-3,4,7,8-tetracarboxylic acid, tricyclo[4.2.2.02,5]decane-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-dimethylnaphthalene-2c , 3c, 6c, 7c-tetracarboxylic acid, (4arH, 8acH)-decahydro-1t, 4t: 5c, 8c-dimethyl naphthalene-2t, 3t, 6c, 7c-tetracarboxylic acid, and the same tetracarboxylic acid Carboxylic acid derivatives (tetracarboxylic dianhydride, etc.), etc. Among these, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane, 2,3,3',4'-biphenyltetracarboxylic acid, and 4,4'-oxy Diphthalic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, (4arH,8acH)-decahydro-1t,4t: 5c , 8c-dimethyl naphthalene-2c, 3c, 6c, 7c-tetracarboxylic acid, (4arH, 8acH)-decahydro-1t, 4t: 5c, 8c-dimethyl naphthalene-2t, 3t, 6c, 7c- Derivatives of tetracarboxylic acids and their acid dianhydrides. These tetracarboxylic acid components can be used alone or in combination.

In addition, when the diamine component that provides the repeating unit represented by the chemical formula (1) is not the diamine component of the combination, the tetracarboxylic acid component that provides other repeating units may also provide the repeating unit represented by the chemical formula (1). The tetracarboxylic acid component, namely CpODA, etc.

As the diamine component providing other repeating units, in addition to TFMB, any other aromatic or aliphatic diamines can also be used. For example, p-phenylenediamine, m-phenylenediamine, benzidine, 3,3'-diamino-biphenyl, 3,3'-bis(trifluoromethyl)benzidine, m-toluidine, 4,4'-Diaminobenzoanilide, 3,4'-Diaminobenzoanilide, 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-aminophenyl) ester, bis (p-Aminobenzoic acid) p-phenylene ester, bis(4-aminophenyl)-[1,1'-biphenyl]-4,4'-dicarboxylate, [1,1'-biphenyl ]-4,4'-Diylbis(4-aminobenzoate), 4,4'-oxydiphenylamine, 3,4'-oxydiphenylamine, 3,3'-oxydiphenylamine , bis(4-aminophenyl)sulfide, p-methylenebis(phenylenediamine), 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminobenzene) oxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis (4-Aminophenyl)hexafluoropropane, bis(4-aminophenyl)terine, 3,3-bis((aminophenoxy)phenyl)propane, 2,2-bis(3-amine) Bis-4-hydroxyphenyl)hexafluoropropane, bis(4-(4-aminophenoxy)diphenyl)terine, bis(4-(3-aminophenoxy)diphenyl)terine, Octafluorobenzidine, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 3,3'- Difluoro-4,4'-diaminobiphenyl, 9,9-bis(4-aminophenyl)fluorine, 4,4'-(spiro[fluorine-9,9'-xanthene]-3' ,6'-diylbis(oxy)diphenylamine, 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-diamine -2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamine Amino-2-isobutylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, 1, 2-Diaminocyclohexane, 1,4-diaminocyclohexane, etc. and their derivatives. Among these, preferred are p-phenylenediamine, m-benphenylamine, 4,4'-oxydiphenylamine, 1,4-bis(4-aminophenoxy)benzene, and 4,4'- Bis(4-aminophenoxy)biphenyl, 9,9-bis(4-aminophenyl)fluorine, 4,4'-(spiro[fluorine-9,9'-xanthene]-3', 6'-Diylbis(oxy))diphenylamine, etc. These diamine components can be used individually or in combination.

In addition, when the tetracarboxylic acid component that provides the repeating unit represented by the chemical formula (1) is not the tetracarboxylic acid component of the combination, the diamine component that provides other repeating units may also provide the repeating unit represented by the chemical formula (1). The diamine component of the unit is TFMB.

The polyimide solution composition of the first embodiment of the present invention and the polyimide solution composition of the second embodiment of the invention (hereinafter also simply referred to as the polyimide of the present invention and the polyimide of the present invention) Amine solution composition), for example, can be produced by the following method. However, the manufacturing method of the polyimide of this invention and the polyimide solution composition of this invention is not limited to the following manufacturing method.

The tetracarboxylic acid component and the diamine component such as tetracarboxylic dianhydride are made to be approximately equimolar, and preferably the molar ratio of the diamine component to the tetracarboxylic acid component is [moles of diamine component/tetracarboxylic acid component] The molar number of the acid component] is preferably 0.90 to 1.10, more preferably 0.95 to 1.05, and the polyimide solution composition of the present invention can be preferably obtained by reacting in the solvent.

More specifically, the diamine component is dissolved in the solvent, and a tetracarboxylic acid component such as tetracarboxylic dianhydride is slowly added to the solution while stirring. Depending on the needs, it is preferably in the range of room temperature to 80°C. After internal stirring for 0.5 to 30 hours, the temperature is raised to perform an imidization reaction to obtain a polyimide solution. The temperature may also be raised immediately after adding the tetracarboxylic acid component to perform the imidization reaction. Moreover, the addition order of a diamine component and a tetracarboxylic acid component may be reversed, or a diamine component and a tetracarboxylic acid component may be added to a solvent simultaneously.

The method of imidization is not particularly limited, and a conventional method of thermal imidization or chemical imidization can be preferably applied. For example, a solution containing a tetracarboxylic acid component such as tetracarboxylic dianhydride and a diamine component is stirred at a temperature in the range of 100°C or higher, preferably 120°C or higher, and more preferably 150 to 250°C for 0.5 to 72 hours. , the tetracarboxylic acid component and the diamine component are reacted, whereby the imidization reaction can be carried out. In the case of chemical imidization, a chemical imidization agent (an acid anhydride such as acetic anhydride or an amine compound such as pyridine, isoquinoline or triethylamine) is added to the reaction solution to react. If required, an imidization catalyst or the like can also be added to the reaction solution to carry out the reaction.

Alternatively, the imidization reaction may be performed while removing water generated during the reaction.

When the diamine component is excessive in the molar ratio between the tetracarboxylic acid component and the diamine component, a carboxylic acid derivative approximately equal to the excess molar number of the diamine component can be added as needed to make the tetracarboxylic acid component The molar ratio of the acid component and the diamine component is approximately equal. The carboxylic acid derivative here is preferably a tetracarboxylic acid that does not substantially increase the viscosity of the polyimide solution, that is, is substantially irrelevant to molecular chain extension, or a tricarboxylic acid that functions as an end-capping agent. Carboxylic acid and its anhydride, dicarboxylic acid and its anhydride, etc.

The solvent used when preparing the polyimide solution is preferably N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1 , aprotic solvents such as 3-dimethyl-2-imidazolidinone and dimethyl styrene, especially N,N-dimethylacetamide and N-methyl-2-pyrrolidone; As long as the raw material monomer components and the produced polyimide can be dissolved, various solvents can be used without any problem, and their structures are not particularly limited. As the solvent, it is preferable to use amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ- cyclic ester solvents such as valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, ethyl carbonate, propyl carbonate, etc. Carbonate solvents, glycol solvents such as triethylene glycol, m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol and other phenol solvents, acetophenone, 1,3-dimethyl-2- Imidazolidinone, cyclotenine, dimethyl terine, etc. Furthermore, other general organic solvents can also be used, namely phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethylcellulose, butylcellulose Su, 2-methylcellulose threate, ethylcellulose threate, butylcellulose threate, 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 essence, naphtha solvent, etc. In addition, solvents can also be used in combination.

After the imidization reaction is carried out in the above manner, the obtained reaction solution can be used as the polyimide solution composition of the present invention directly, or by condensing or diluting it, or even adding additives described below as needed. . Alternatively, the soluble polyimide is isolated from the obtained reaction solution, and then the isolated polyimide is added to the solvent to obtain the polyimide solution composition of the present invention. Isolation of the polyimide can be performed, for example, by dropping the reaction solution containing the obtained soluble polyimide into a poor solvent such as water or by mixing the reaction solution to precipitate (re-precipitate) the polyimide. ).

The polyimide solution composition of the present invention at least contains polyimide and a solvent. The proportion of polyimide is more than 5 mass%, preferably 10 mass%, relative to the total amount of solvent and polyimide. Above, more preferably 15% by mass or more, particularly preferably 20% by mass or more. If the concentration is too low, for example, when producing a polyimide film, it will be difficult to control the film thickness of the resulting polyimide film. In addition, the polyimide content is usually 60 mass% or less, preferably 50 mass% or less.

There is no problem as long as the solvent for the polyimide solution composition of the present invention can dissolve the polyimide, and its structure is not particularly limited. Examples of the solvent for the polyimide solution composition include the same solvents used for preparing the polyimide solution. The solvent used for preparing the polyimide solution can be directly used as the polyimide solution composition. solvents used. In addition, the solvent can be removed from the polyimide solution composition prepared above according to the demand, or the solvent can also be added.

In the present invention, the logarithmic viscosity of the polyimide is not particularly limited, but the logarithmic viscosity of the N,N-dimethylacetamide solution at a concentration of 0.5g/dL at 30°C is preferably 0.2dL/g or more. More preferably, it is 0.4dL/g or more, and particularly preferably, it is 0.5dL/g or more. If the logarithmic viscosity is above 0.2dL/g, the resulting polyimide will have excellent mechanical strength and heat resistance.

In the present invention, the viscosity (rotational viscosity) of the polyimide solution composition is not particularly limited. The rotational viscosity measured using an E-type rotational viscometer at a temperature of 25°C and a shear speed of 20sec ^-1 is preferably 0.01~1000Pa. ‧sec, preferably 0.1~100Pa‧sec. In addition, thixotropy can also be provided according to needs. The viscosity within the above range is easy to handle during coating or film formation, can suppress eye holes, has excellent coating uniformity, and can obtain a good coating film.

The polyimide solution composition of the present invention can contain coupling agents such as antioxidants, fillers (inorganic particles of silica, etc.), dyes, pigments, silane coupling agents, primers, and flame retardant materials according to needs. , defoaming agent, leveling agent, rheology control agent (flow aid), stripping agent, etc.

The polyimide of the present invention can be preferably obtained by removing the solvent from the polyimide solution composition prepared above. For example, a polyimide film/substrate laminate can be produced by casting and coating the polyimide solution composition on the substrate, and heating the polyimide solution composition on the substrate to remove the solvent. The temperature of the heat treatment is not particularly limited, but is usually 80 to 500°C, preferably 100 to 500°C, and more preferably about 150 to 450°C. The heat treatment can be performed in a vacuum, in an inert gas such as nitrogen, or in air, but it is usually desirably performed in a vacuum or an inert gas. Next, the polyimide film formed on the base material is peeled off from the base material, thereby producing a polyimide film.

Here, the base material is not particularly limited, and for example, base materials such as ceramics (glass, silicon, alumina), metals (copper, aluminum, stainless steel), heat-resistant plastic films (polyimide films), etc. can be used. In one embodiment, it is preferable to use glass as a base material and a polyimide film/glass substrate laminate in which a polyimide film is formed on the glass base material. For example, it can be preferably used in manufacturing applications. For display substrates, etc.

Furthermore, the polyimide solution composition is cast and coated on the base material, and the polyimide solution composition on the base material is dried to the extent of having self-supporting properties, and the obtained self-supporting film is formed from A polyimide film can be preferably produced by peeling off the base material, heating the film with its ends fixed, and then removing the solvent. The drying conditions during the production of the self-supporting membrane can be appropriately determined. For example, the polyimide solution composition may be dried on the base material within a temperature range of about 50 to 300°C. The heat treatment temperature of the self-supporting film is not particularly limited, but is usually 80 to 500°C, preferably 100 to 500°C, and more preferably about 150 to 480°C. In this method, the heat treatment can be performed in a vacuum, in an inert gas such as nitrogen, or in air, but it is usually desirably performed in a vacuum or an inert gas.

In addition, the form of the polyimide of the present invention is not limited to a film or a laminate of a polyimide film and other base materials. Preferable examples include coating films, powders, beads, molded bodies, foams, and the like.

The polyimide of the present invention thus obtained has a linear thermal expansion coefficient between 100 and 250° C. of preferably 25 ppm/K or less, more preferably 20 ppm/K or less, when measured as a film with a thickness of 10 μm. The best value is below 15ppm/K. If the linear thermal expansion coefficient is large, the difference in linear thermal expansion coefficient with a conductor such as metal becomes large, which may cause defects such as increased warpage when forming a circuit board. In addition, the linear thermal expansion coefficient in the present invention is a value measured for a polyimide film with a film thickness of 10 μm under the conditions of a film width of 4 mm, a distance between chucks of 15 mm, a tensile load of 2 g, and a heating rate of 20°C/min. , the linear thermal expansion coefficient tends to become smaller as the film thickness becomes thicker.

When the polyimide of the present invention is measured as a film with a thickness of 10 μm, the light transmittance at a wavelength of 400 nm is preferably 80% or more, more preferably 83% or more. When polyimide films are used in display applications, etc., if the light transmittance is low, the light source must be made stronger, which may cause energy consumption. Measure questions like this. In addition, the light transmittance at a wavelength of 400 nm tends to decrease as the film thickness increases.

When measured as a film with a thickness of 10 μm, the haze of the polyimide of the present invention is preferably 2% or less, more preferably 1.5% or less, and particularly preferably 1% or less. When a polyimide film is used for display applications, etc., if the haze is high, the image may be blurred due to light scattering. In addition, haze tends to increase as the film thickness increases.

Although the film composed of the polyimide of the present invention also depends on the use, the thickness of the film is preferably 1 μm~250 μm, more preferably 1 μm~150 μm, further preferably 1 μm~100 μm, and particularly preferably 1 μm~80 μm. When a polyimide film is used for light transmission, if the polyimide film is too thick, the light transmittance may become low.

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

A flexible conductive substrate can be obtained, for example, by the following method. That is, as a first method, in the polyimide film/base material laminate, the polyimide film is not peeled off from the base material, but is formed on the surface of the polyimide film by sputtering, A conductive layer of a conductive substance (metal or metal oxide, conductive organic substance, conductive carbon, etc.) is formed by evaporation, printing, etc., to produce a conductive laminate of conductive layer/polyimide film/substrate. Then, 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 can be peeled off from the base material of the polyimide film/base material laminate to obtain a polyimide film, and the surface of the polyimide film can be formed in the same manner as in the first method. Conductive layer of conductive substances (metal or metal oxide, conductive organic matter, conductive carbon, etc.), and A transparent and flexible conductive substrate composed of a conductive layer/polyimide film laminate or a conductive layer/polyimide film/conductive laminate can be obtained.

In addition, in the first and second methods, before forming the conductive layer on the surface of the polyimide film, gases such as water vapor, oxygen, etc. can also be formed according to needs through sputtering, evaporation, gel-sol method, etc. Inorganic layers such as barrier layers and light adjustment layers.

In addition, the conductive layer can preferably form a circuit by photolithography, various printing methods, inkjet methods, etc.

The substrate of the present invention thus obtained has a circuit with a conductive layer on the surface of the polyimide film composed of the polyimide of the present invention via a gas barrier layer or an inorganic layer as required. This substrate has excellent flexibility, high transparency, bendability, and heat resistance, and even has an extremely low coefficient of linear thermal expansion, making it easy to form precision circuits. Therefore, the substrate can be preferably used as a substrate for a display, a touch screen, or a solar cell.

That is, by further forming transistors (inorganic transistors, organic transistors) on the substrate through evaporation, various printing methods, or inkjet methods, a flexible thin film transistor can be produced, and can be preferably used as a display Liquid crystal elements, EL elements, and photoelectric elements for devices.

Furthermore, in the above-mentioned first method, not only the conductive layer can be formed on the surface of the polyimide film/substrate laminate, but also after at least a part of the transistor and/or other elements or structures required for the device are formed, Then peel off the base material.

[Example]

Hereinafter, the present invention will be further explained through Examples and Comparative Examples. In addition, the present invention is not limited to the following examples.

In each of the following examples, the following methods were used for evaluation.

<Evaluation of polyimide solution>

[Imination rate]

Tetramethylsilane was used as the internal standard material, dimethylsyanine-d ₆ was used as the dilution solvent of the polyimide solution, and ¹ H-NMR measurement of the polyimide solution was performed with M-AL400 manufactured by JEOL Ltd. The ratio of the integrated value of the peak of aromatic protons to the integrated value of the peak of amide protons is used to calculate the amide imidization rate according to the following formula (I).

Imination rate (%)={1-(Y/Z)×(1/X)}×100 (I)

X: Integrated value of the amide proton peak/integrated value of the aromatic proton peak when the amide imidization rate is 0%, calculated from the amount of the monomer added.

Y: Integrated value of the amide proton peak measured by ¹ H-NMR

Z: Integrated value of the aromatic proton peak measured by ¹ H-NMR

<Evaluation of polyimide membrane>

[400nm light transmittance]

The light transmittance of a polyimide film with a film thickness of 10 μm and a size of 5 × 5 cm ² at a wavelength of 400 nm was measured using a UV-visible light spectrometer/V-650DS (Japan Spectroscopic Co., Ltd.).

[Haze]

Using a nephelometer/NDH2000 (manufactured by Nippon Denshoku Industries), the haze of a polyimide film with a film thickness of 10 μm and a size of 5 × 5 cm ² was measured in accordance with the specifications of JIS K7136.

[Coefficient of Linear Thermal Expansion (CTE)]

A polyimide film with a film thickness of 10 μm was cut into a short piece with a width of 4 mm to serve as a test piece, and TMA/SS6100 (manufactured by SII NanoTechnology Co., Ltd.) was used. Distance 15mm, tensile load 2g, heating rate 20℃/min to 500℃. From the obtained TMA curve, the linear thermal expansion coefficient from 100°C to 250°C was obtained.

[Tensile elastic coefficient, breaking point elongation, breaking point stress]

The polyimide film was punched into a dumbbell shape according to the IEC-540 (S) standard to serve as a test piece (width: 4 mm). The initial tensile strength was measured using TENSILON manufactured by ORIENTEC with a length between chucks of 30 mm and a tensile speed of 2 mm/min. Elongation elastic coefficient, breaking point elongation, breaking point stress.

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

[Diamine component]

TFMB: 2,2’-bis(trifluoromethyl)benzidine [Purity: 99.83% (GC analysis)]

BAFL: 9,9-bis(4-aminophenyl)fluoride

4,4’-ODA: 4,4’-oxydiphenylamine [Purity: 99.9% (GC analysis)]

BAPB: 4,4’-bis(4-aminophenoxy)biphenyl

TPE-Q: 1,4-bis(4-aminophenoxy)benzene

[tetracarboxylic acid component]

CpODA: norbornane-2-spiro-α-cyclopentanone-α’-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic dianhydride

PMDA-H: 1,2,4,5-cyclohexanetetracarboxylic dianhydride [Purity: 99.9% (GC analysis)]

[Solvent]

GBL: gamma-butyrolactone

DMAc: N,N-dimethylacetamide

[Example 1]

Add 7.00g (21.9 mmol) of TFMB and 6.23g (17.9 mmol) of BAFL into the nitrogen-substituted reaction vessel. The total mass of the feed monomers (the sum of the diamine component and the carboxylic acid component) becomes 95.44g (31.81g of DMAc and 63.63g of GBL) a mixed solvent of DMAc and GBL (DMAc:GBL=1:2 (weight ratio)) was added in an amount of 23% by mass, and the mixture was stirred at room temperature for 1 hour. To this solution, 15.28 g (39.7 mmol) of CpODA was slowly added. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 450°C on the glass substrate in a nitrogen environment (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 2]

Add 9.00g (28.1 mmol) of TFMB and 6.53g (18.7 mmol) of BAFL into the nitrogen-substituted reaction vessel. The total mass of the feed monomers (the sum of the diamine component and the carboxylic acid component) becomes 112.26g DMAc was added in an amount of 23% by mass, and stirred at room temperature for 1 hour. To this solution, 18.00 g (46.8 mmol) of CpODA was slowly added. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and in a nitrogen environment (oxygen concentration below 200 ppm), it is directly heated from room temperature to 430°C on the glass substrate to remove the solvent and obtain a free Color-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 with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 3]

Add 9.00g (28.1 mmol) of TFMB and 4.20g (12.0 mmol) of BAFL into the nitrogen-substituted reaction vessel. The total mass of the feed monomers (the sum of the diamine component and the carboxylic acid component) becomes 95.85g DMAc was added in an amount of 23% by mass, and stirred at room temperature for 1 hour. To this solution was slowly added 15.43 g (40.2 mmol) of CpODA. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 410°C on the glass substrate in a nitrogen environment (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 4]

Add 10.00g (31.2 mmol) of TFMB and 2.72g (7.8 mmol) of BAFL into the nitrogen-substituted reaction vessel. The total mass of the feed monomers (the sum of the diamine component and the carboxylic acid component) becomes 92.82g DMAc was added in an amount of 23% by mass, and stirred at room temperature for 1 hour. To this solution, 15.00 g (39.0 mmol) of CpODA was slowly added. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 410°C on the glass substrate in a nitrogen environment (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 5]

Add 10.00g (31.2 mmol) of TFMB and 1.20g (3.5 mmol) of BAFL into the nitrogen-substituted reaction vessel. The total mass of the feed monomers (the sum of the diamine component and the carboxylic acid component) becomes 82.18g DMAc was added in an amount of 23% by mass, and stirred at room temperature for 1 hour. To this solution was slowly added 13.34 g (34.7 mmol) of CpODA. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 410°C on the glass substrate in a nitrogen environment (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 6]

40.00g (124.9 mmol) of TFMB was added to the nitrogen-substituted reaction vessel, and 264.04g of DMAc was added so that the total mass of the feed monomers (the sum of the diamine component and the carboxylic acid component) became 25% by mass, and the chamber was filled with Stir at warm temperature for 1 hour. To this solution, 48.01 g (124.9 mmol) of CpODA was slowly added. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain Homogeneous and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 410°C on the glass substrate in a nitrogen environment (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 7]

Add 8.00g (25.0 mmol) of TFMB, 2.90g (8.3 mmol) of BAFL and 1.67g (8.3 mmol) of 4,4'-ODA into the nitrogen-substituted reaction vessel to feed 95.66 g of DMAc was added so that the total mass of the monomers (the sum of the diamine component and the carboxylic acid component) became 23% by mass, and the mixture was stirred at room temperature for 1 hour. To this solution was slowly added 16.00 g (41.6 mmol) of CpODA. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 410°C on the glass substrate in a nitrogen atmosphere (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 8]

Add 8.00g (25.0 mmol) of TFMB, 4.35g (12.5 mmol) of BAFL and 1.53g (4.2 mmol) of BAPB into the nitrogen-substituted reaction vessel to feed monomers 100.07 g of DMAc was added so that the total mass (the sum of the diamine component and the carboxylic acid component) became 23% by mass, and the mixture was stirred at room temperature for 1 hour. To this solution was slowly added 16.00 g (41.6 mmol) of CpODA. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 410°C on the glass substrate in a nitrogen atmosphere (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 9]

Add 10.00g (31.2 mmol) of TFMB and 4.66g (13.4 mmol) of BAFL into the nitrogen-substituted reaction vessel. The total mass of the feed monomers (the sum of the diamine component and the carboxylic acid component) becomes 90.06g (30.02g of DMAc and 60.04g of GBL) a mixed solvent of DMAc and GBL (DMAc:GBL=1:2 (weight ratio)) was added in an amount of 25% by mass, and the mixture was stirred at room temperature for 1 hour. To this solution, 12.86 g (33.5 mmol) of CpODA and 2.5 g (11.1 mmol) of PMDA-H were slowly added. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 410°C on the glass substrate in a nitrogen environment (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Example 10]

Add 10.00g (31.2 mmol) of TFMB and 3.91g (13.4 mmol) of TPE-Q into the nitrogen-substituted reaction vessel to determine the total mass of the feed monomer (the sum of the diamine component and the carboxylic acid component). ) into 25% by mass, 93.18g (31.06g of DMAc and 62.12g of GBL) a mixed solvent of DMAc and GBL (DMAc:GBL=1:2 (weight ratio)) was added, and the mixture was stirred at room temperature for 1 hour. To this solution was slowly added 17.15 g (44.6 mmol) of CpODA. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 370°C on the glass substrate in a nitrogen environment (oxygen concentration below 200 ppm) to remove the solvent and obtain a colorless and transparent polyimide film/glass laminate. body. Next, the obtained polyimide film/glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Comparative example 1]

Add 7.00g (21.9 mmol) of TFMB and 7.62g (21.9 mmol) of BAFL into the nitrogen-substituted reaction vessel. The total mass of the feed monomers (the sum of the diamine component and the carboxylic acid component) becomes 94.26g DMAc was added in an amount of 25% by mass, and stirred at room temperature for 1 hour. To this solution was slowly added 16.80 g (43.7 mmol) of CpODA. Stir at 70°C for 3 hours and 160°C for 7 hours to obtain a uniform and viscous polyimide solution. The resulting polyimide solution has an imidization rate of more than 95%.

The polyimide solution is coated on a glass substrate, and heated directly from room temperature to 410°C on the glass substrate in a nitrogen environment (oxygen concentration below 200 ppm) to remove the solvent and obtain a free Color-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 with a film thickness of 10 μm.

The properties of the polyimide film were measured and the results are shown in Table 1.

[Possibility of industrial use]

According to the present invention, it is possible to provide a polyimide that achieves both high transparency and low linear thermal expansion at a high level, that is, a polyimide with high transparency and an extremely low linear thermal expansion coefficient. Furthermore, according to the present invention, it is possible to provide a polyimide solution composition capable of obtaining a polyimide having high transparency and extremely low linear thermal expansion coefficient. The polyimide of the present invention and the polyimide obtained from the polyimide solution composition of the present invention have high transparency and low linear thermal expansion coefficient, and are easy to form precision circuits, and are particularly suitable for use in forming displays, etc. substrate.

Claims (10)

A polyimide containing more than 50 mol% of the repeating unit represented by the following chemical formula (1) relative to all repeating units, characterized by: measured with a film having a thickness of 10 μm Under normal circumstances, the linear thermal expansion coefficient between 100 and 250°C is below 25ppm/K, and the light transmittance at a wavelength of 400nm is above 80%;

This does not include polyimide obtained by using a diamine component represented by the following formula (1-1);

In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ independently represent a halogen atom, an alkyl group with 1 to 5 carbon atoms or an alkoxy group with 1 to 5 carbon atoms. R ₆ and R ₇ They each independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 5 carbon atoms, or an alkoxy group with 1 to 5 carbon atoms. a, b, d and e each independently represent an integer from 0 to 4, and then c It represents an integer from 0 to 2. A polyimide solution composition, characterized in that the following polyimide is dissolved in a solvent; the polyimide contains more than 50 repeating units represented by the following chemical formula (1) relative to all repeating units Mol%, and the imidization rate exceeds 90%; [Chemical 2]

This does not include polyimide obtained by using a diamine component represented by the following formula (1-1);

In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ independently represent a halogen atom, an alkyl group with 1 to 5 carbon atoms or an alkoxy group with 1 to 5 carbon atoms. R ₆ and R ₇ They each independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 5 carbon atoms, or an alkoxy group with 1 to 5 carbon atoms. a, b, d and e each independently represent an integer from 0 to 4, and then c It represents an integer from 0 to 2. A polyimide obtained by removing the solvent from the polyimide solution composition of item 2 of the patent application. A polyimide film is obtained by removing the solvent from the polyimide solution composition of item 2 of the patent application. For example, the polyimide film in Item 3 of the patent scope or the polyimide film in Item 4 of the patent scope has a linear thermal expansion coefficient between 100 and 250°C of 25 ppm when measured with a film thickness of 10 μm. /K or less, and the light transmittance at a wavelength of 400nm is more than 80%. A laminate characterized by forming a film containing polyimide as claimed in claim 1 or a polyimide film as claimed in claim 4 or 5 on a glass substrate. A substrate for a display, a touch screen or a solar cell, which is characterized by containing a polyimide as described in Item 1 or 3 of the patent application or a polyimide as described in Item 4 or 5 of the patent application. Imide membrane. A method for manufacturing a laminated body including a base material and a polyimide film laminated on the base material, including the steps of applying the polyimide solution composition as described in Item 2 of the patent application to the base material; and applying the polyimide solution composition to the base material. The step of heating the polyimide solution composition on the substrate. A method for manufacturing a polyimide film, including: the steps of applying the polyimide solution composition as described in Item 2 of the patent application to a base material; and heating the polyimide solution composition on the base material. step; and the step of peeling off the polyimide film formed on the base material from the base material. A method for manufacturing a polyimide film, including the steps of coating a polyimide solution composition as described in item 2 of the patent application on a substrate; drying the polyimide solution composition to obtain a self-supporting The step of forming a self-supporting film; and the steps of peeling the self-supporting film from the base material and heating it.