JP7069478B2 - Polyimide, polyimide solution composition, polyimide film, and substrate - Google Patents

Description

The present invention relates to a polyimide solution composition for obtaining a polyimide having high transparency and an extremely low coefficient of linear thermal expansion, and a polyimide having high transparency and an extremely low coefficient of linear thermal expansion. The present invention also relates to a polyimide film and a substrate.

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

Aromatic polyimides are essentially yellowish brown due to intramolecular conjugation and formation of charge transfer complexes. Therefore, as a means for suppressing coloring, for example, by introducing a fluorine atom into the molecule, imparting flexibility to the main chain, introducing a bulky group as a side chain, etc., the formation of intramolecular conjugation and charge transfer complex is inhibited. Then, a method of expressing transparency has been proposed.

Further, a method of exhibiting transparency by using a semi-alicyclic or full alicyclic polyimide that does not form a charge transfer complex in principle has also been proposed. In particular, a highly transparent semi-alicyclic polyimide using an aromatic tetracarboxylic acid dianhydride as a tetracarboxylic acid component and an alicyclic diamine as a diamine component, and an alicyclic tetracarboxylic acid dianhydride as a tetracarboxylic acid component. Many highly transparent semi-lipid ring-type polyimides using aromatic diamine as an anhydride and diamine components have been proposed.

For example, in Patent Document 1, norbornan-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornan-5,5'', 6,6''-tetra as a tetracarboxylic acid component. Carboxylic acid dianilides (abbreviation: CpODA) is used, and 2,2'-bis (trifluoromethyl) benzidine (abbreviation: TFMB) or TFMB and other aromatic diamines (eg, TFMB:) are used as diamine components. A polyimide using 4,4'-diaminobenzanilide: 9,9-bis (4-aminophenyl) fluorene = 5: 4: 1 (molar ratio)) is disclosed. Patent Document 2 uses CpODA having a specific stereoisomer ratio as the tetracarboxylic acid component, TFMB as the diamine component, and other aromatic diamines (eg, TFMB: 4,4'-diaminobenzanilide). = 5: 5 (molar ratio), etc.) is disclosed. However, in the examples of Patent Document 1 and Patent Document 2, the polyimide obtained from CpODA and a diamine component containing 50 mol% or more of TFMB has high transparency, but has a relatively high coefficient of linear thermal expansion. It tends to be big. If the coefficient of linear thermal expansion of polyimide is large and the difference in coefficient of linear thermal expansion from a conductor such as metal is large, warpage may occur when forming a circuit board, making it difficult to form fine circuits, especially for display applications. May become.

On the other hand, Patent Document 3 discloses a polyimide precursor having an imidization ratio of 30% or more and 90% or less, which is produced by thermal imidization from a tetracarboxylic acid component and a diamine component containing a specific aromatic diamine. Has been done. More specifically, in the examples of Patent Document 3, CpODA is used as the tetracarboxylic acid component, TFMB is used as the diamine component, and other aromatic diamines (for example, TFMB: 4,4'-diaminobenzanilide = A polyimide precursor having an imidization ratio of 33 to 60% is produced using 5: 5 (molar ratio) or the like). Regarding the imidization rate, Patent Document 3 describes a case where a polyimide precursor having an imidization rate of 0% is imidized by imidizing a polyimide precursor having an imidization rate of 30% or more to produce a polyimide. On the other hand, when the imidization ratio exceeds 90%, the solubility of the polyimide precursor (or polyimide) is lowered and the polyimide precursor (or the polyimide precursor) (or the polyimide precursor) is obtained. It is described that (polyimide) may precipitate and a polyimide having excellent properties may not be obtained.

Further, Patent Document 4 describes a polyimide resin containing a structural unit A derived from tetracarboxylic acid dianhydride and a structural unit B derived from a diamine compound, wherein the structural unit A is a structural unit derived from CpODA. (A-1), a structural unit derived from pyromellitic acid dianhydride (A-2), and a structural unit derived from 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride (A-3). The constituent unit B comprises at least one of the constituent units (B-1) derived from 9,9-bis (4-aminophenyl) fluorene, and the constituent unit (B-1) in the constituent unit B. A polyimide resin having a ratio of 60 mol% or more is disclosed. More specifically, in Example 4 of Patent Document 4, a polyimide resin is produced from CpODA (A-1) and 9,9-bis (4-aminophenyl) fluorene (B-1). In Example 5 of Patent Document 4, CpODA (A-1), 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride (A-3) and 9,9-bis (4-aminophenyl) fluorene ( A polyimide resin ((A-1) :( A-3) = 1: 1 (molar ratio)) is produced from B-1). In Example 6 of Patent Document 4, a polyimide resin is obtained from CpODA (A-1), 9,9-bis (4-aminophenyl) fluorene (B-1), and 2,2'-dimethylbenzidine (B-2). ((B-1) :( B-2) = 4: 1 (molar ratio)) is manufactured. In the examples of Patent Document 4, after obtaining the polyimide resin solution, the polyimide resin solution is applied on the substrate and dried to remove the solvent to obtain the polyimide film.

Further, in Example 1 and Comparative Example 1 of Patent Document 5, CpODA, 4,4'-diamino-2,2'-dimethylbiphenyl and 9,9-bis (4-aminophenyl) fluorene (molar ratio:: The polyimide obtained from 1/1) and the polyimide obtained from CpODA and 9,9-bis (4-aminophenyl) fluorene are described. In Example 1 and Comparative Example 1 of Patent Document 5, after obtaining a polyimide solution, the polyimide solution is applied onto a substrate and the coating film is cured to obtain a polyimide film.

International Publication No. 2013/179727 International Publication No. 2014/046064 International Publication No. 2014/208704 International Publication No. 2017/191822 Japanese Unexamined Patent Publication No. 2017-13302

The present invention provides a polyimide that achieves both high transparency and low linear thermal expansion at a high level, that is, a polyimide having high transparency and an extremely low coefficient of linear thermal expansion, and high transparency. It is an object of the present invention to provide a polyimide solution composition capable of obtaining a polyimide having an extremely low coefficient of linear thermal expansion.

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

2. 2. A polyimide solution containing a repeating unit represented by the following chemical formula (1) in an amount of more than 50 mol% with respect to all the repeating units, and a polyimide having an imidization ratio of more than 90% dissolved in a solvent. Composition.

3. 3. A polyimide obtained by removing a solvent from the polyimide solution composition according to Item 2.
4. A polyimide film obtained by removing a solvent from the polyimide solution composition according to Item 2.
5. The above-mentioned item is characterized in that the linear thermal expansion coefficient between 100 and 250 ° C. is 25 ppm / K or less and the light transmittance at a wavelength of 400 nm is 80% or more when the film thickness is measured at 10 μm. 3. The polyimide according to item 3 or the polyimide film according to item 4 above.
6. A laminate comprising the polyimide according to Item 1 or the polyimide film according to Item 4 or 5 formed on a glass substrate.
7. A substrate for a display, a touch panel, or a solar cell, which comprises the polyimide according to Item 1 or 3 or the polyimide film according to Item 4 or 5.

8. The step of applying the polyimide solution composition according to Item 2 to the substrate, and
A method for producing a polyimide film / base material laminate, which comprises a step of heating the polyimide solution composition on a base material.
9. The step of applying the polyimide solution composition according to Item 2 to the substrate, and
The step of heating the polyimide solution composition on the substrate and
A method for producing a polyimide film, which comprises a step of peeling a polyimide film formed on a substrate from the substrate.
10. The step of applying the polyimide solution composition according to Item 2 to the substrate, and
The step of drying the polyimide solution composition to obtain a self-supporting film, and
The step of peeling the self-supporting film from the substrate and heating it,
A method for manufacturing a polyimide film containing.

INDUSTRIAL APPLICABILITY 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 having high transparency and an extremely low coefficient of linear thermal expansion. Further, according to the present invention, it is possible to provide a polyimide solution composition capable of obtaining a polyimide having high transparency and an extremely low coefficient of linear thermal expansion.

Since the polyimide of the present invention and the polyimide obtained from the polyimide solution composition of the present invention have high transparency and an extremely low coefficient of linear thermal expansion, it is easy to form a fine circuit, and a substrate for display applications or the like can be used. It can be suitably used for forming. Further, the polyimide of the present invention and the polyimide obtained from the polyimide solution composition of the present invention can be suitably used for forming a substrate for a touch panel and a solar cell.

In the present specification, the following abbreviations are used as appropriate.
CpODA: Norbornan-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid dianhydride CpODA, etc .: Norbornan-2- Spiro-α-cyclopentanone-α'-spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acids, etc. (Tetracarboxylic acids, etc. are tetracarboxylic acid and tetracarboxylic acid. Represents a tetracarboxylic acid derivative such as acid dianhydride, tetracarboxylic acid silyl ester, tetracarboxylic acid ester, tetracarboxylic acid chloride)
TFMB: 2,2'-bis (trifluoromethyl) benzidine The tetracarboxylic acid component that gives the repeating unit represented by the chemical formula (1) is CpODA or the like, and the repeating unit represented by the chemical formula (1) is used. The given diamine component is TFMB.

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

The polyimide obtained from the conventionally known tetracarboxylic acid component mainly containing CpODA and the like and the diamine component mainly containing TFMB is an imide in which the tetracarboxylic acid component and the diamine component are mixed in a solvent at a relatively low temperature. After reacting while suppressing the formation to obtain a solution containing a polyimide precursor such as polyamic acid, this polyimide precursor solution is applied to a substrate, heated to remove (dry) the solvent, and imidized. It is manufactured by. As described above, the polyimide thus obtained has high transparency, but tends to have a relatively large coefficient of linear thermal expansion. On the other hand, in the present invention, the tetracarboxylic acid component mainly containing CpODA and the like and the diamine component mainly containing TFMB are reacted in a solvent under the condition that the imidization reaction proceeds, and the imidization rate is 90. After obtaining a solution (or solution composition) containing a soluble polyimide having an imidization ratio of more than%, preferably 95% or more, the polyimide is removed from the polyimide solution (or solution composition) to produce a polyimide. do. When the polyimide is manufactured by this method, the coefficient of linear thermal expansion can be significantly reduced as compared with the conventional one while maintaining high transparency. As a result, both high transparency and low linear thermal expansion can be achieved at a high level, resulting in a polyimide with high transparency and an extremely low coefficient of linear thermal expansion.

In the polyimide of the first embodiment of the present invention, the content of the repeating unit represented by the chemical formula (1) derived from CpODA or the like and TFMB exceeds 50 mol% with respect to all the repeating units, for example. It may be 80 mol% or more, further 90 mol% or more, and further 100 mol%.

The polyimide solution composition of the second embodiment of the present invention contains the repeating unit represented by the chemical formula (1) in an amount of more than 50 mol% with respect to all the repeating units, and the imidization ratio exceeds 90%. A solution composition in which polyimide having an imidization ratio of 95% or more is dissolved in a solvent. By removing the solvent from this polyimide solution composition, a polyimide having high transparency and an extremely low coefficient of linear thermal expansion, for example, a coefficient of linear thermal expansion between 100 and 250 ° C. when measured at a film thickness of 10 μm. A polyimide having a light transmittance of 25 ppm / K or less, preferably 20 ppm / K or less, more preferably 15 ppm / K or less, and a light transmittance of 80% or more, preferably 83% or more at a wavelength of 400 nm can be obtained.
Here, if the imidization rate is low, for example, if the imidization rate is about 30% to 80%, haze occurs and the transparency of the obtained polyimide is lowered, depending on the composition of the polyimide. Sometimes. In particular, in the case of a polyimide composed of the repeating unit of the chemical formula (1) [polyimide obtained from CpODA or the like and TFMB], the haze tends to be large.

Also in the polyimide 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 or the like and TFMB is the content of the repeating unit with respect to all the repeating units. It may exceed 50 mol%, for example 80 mol% or more, further 90 mol% or more, and even 100 mol%.

Here, the imidization ratio is the ratio of the repeating unit of the imide structure to the total of the repeating unit of the amic acid structure and the repeating unit of the imide structure, and the ¹ H-NMR spectrum of the polyimide (polyimide solution composition) is measured. , Can be calculated from the ratio of the integrated value of the peak of aromatic protons (6.2 to 8.5 ppm) and the integrated value of the peak of amide protons (9.5 to 11.0 ppm).

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

Of the six stereoisomers, the tetracarboxylic acid component CpODA used here is trans-endo-endo-norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane. -5,5'', 6,6''-tetracarboxylic acids, etc. (trans-endo-endo form) and / or cis-endo-endo-norbornane-2-spiro-α-cyclopentanone-α'-spiro -2''-Norbornane-5,5'', 6,6''-Tetracarboxylic acids and the like (cis-endo-endo form) may be preferable. In certain embodiments, the proportion of trans-endo-endo and / or cis-endo-endo in total, such as CpODA, is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 90 mol% or more. It is preferably 95 mol% or more, particularly preferably 99 mol% or more.

As CpODA or the like, one type may be used alone, or a plurality of types may be used in combination.

The polyimide in the polyimide solution composition of the first embodiment of the present invention and the polyimide solution composition of the second embodiment of the present invention are of other repeating units other than the repeating unit represented by the chemical formula (1). One or more may be included in the range of 50 mol% or less with respect to all repeating units.

As the tetracarboxylic acid component that gives another repeating unit, any other aromatic or aliphatic tetracarboxylic acid other than CpODA and the like can be used. For example, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 4- (2,5-dioxotetratetra-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2 -Dicarboxylic acid, pyromellitic acid, 3,3', 4,4'-benzophenone tetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 2,3,3', 4'-biphenyltetra Carboxylic acid, 4,4'-oxydiphthalic acid, bis (3,4-dicarboxyphenyl) sulfone dianhydride, m-terphenyl-3,4,3', 4'-tetracarboxylic acid dianhydride, p- Tarphenyl-3,4,3', 4'-tetracarboxylic acid dianhydride, biscarboxyphenyldimethylsilane, bisdicarboxyphenoxydiphenylsulfide, sulfonyldiphthalic acid, 1,2,3,4-cyclobutanetetracarboxylic acid , Isopropylidene diphenoxybisphthalic acid, cyclohexane-1,2,4,5-tetracarboxylic acid, [1,1'-bi (cyclohexane)]-3,3', 4,4'-tetracarboxylic acid, [ 1,1'-bi (cyclohexane)]-2,3,3', 4'-tetracarboxylic acid, [1,1'-bi (cyclohexane)]-2,2', 3,3'-tetracarboxylic acid , 4,4'-methylenebis (cyclohexane-1,2-dicarboxylic acid), 4,4'-(propane-2,2-diyl) bis (cyclohexane-1,2-dicarboxylic acid), 4,4'-oxybis (Cyclohexane-1,2-dicarboxylic acid), 4,4'-thiobis (cyclohexane-1,2-dicarboxylic acid), 4,4'-sulfonylbis (cyclohexane-1,2-dicarboxylic acid), 4,4'. -(Dimethylsilanediyl) bis (cyclohexane-1,2-dicarboxylic acid), 4,4'-(tetrafluoropropane-2,2-diyl) bis (cyclohexane-1,2-dicarboxylic acid), octahydropentalene -1,3,4,6-tetracarboxylic acid, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic acid, 6- (carboxymethyl) bicyclo [2.2.1] heptane -2,3,5-tricarboxylic acid, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic acid, bicyclo [2.2.2] octa-5-en-2,3 7,8-Tetracarboxylic acid, tricyclo [4.2.2.02,5] Decane-3,4,7,8-tetracarboxylic acid, tricyclo [4.2.2.02] , 5] Deca-7-en-3,4,9,10-tetracarboxylic acid, 9-oxatricyclo [4.2.1.02,5] nonane-3,4,7,8-tetracarboxylic acid , (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene-2c, 3c, 6c, 7c-tetracarboxylic acid, (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-di Examples thereof include methanonaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acid, and derivatives of these tetracarboxylic acids (tetracarboxylic acid dianhydride, etc.). Among these, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane, 2,3,3', 4'-biphenyltetracarboxylic acid, 4,4'-oxydiphthalic acid, cyclohexane-1, 2,4,5-Tetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene-2c, 3c, 6c, 7c -Derivatives such as tetracarboxylic acid, (4arH, 8acH) -decahydro-1t, 4t: 5c, 8c-dimethanonaphthalene-2t, 3t, 6c, 7c-tetracarboxylic acid, and acid dianhydrides thereof are more preferable. .. These tetracarboxylic acid components may be used alone or in combination of two or more.

When the diamine component to be combined is not a diamine component that gives a repeating unit represented by the chemical formula (1), the tetracarboxylic acid component that gives another repeating unit is a tetra that gives a repeating unit represented by the chemical formula (1). It may be a carboxylic acid component, that is, CpODA or the like.

As the diamine component that gives another repeating unit, any other aromatic or aliphatic diamines other than TFMB can be used. For example, p-phenylenediamine, m-phenylenediamine, benzidine, 3,3'-diamino-biphenyl, 3,3'-bis (trifluoromethyl) benzidine, m-trizine, 4,4'-diaminobenzanilide, 3 , 4'-diaminobenzanilide, N, N'-bis (4-aminophenyl) terephthalamide, N, N'-p-phenylene bis (p-aminobenzamide), 4-aminophenoxy-4-diaminobenzoate, bis (4-Aminophenyl) terephthalate, biphenyl-4,4'-dicarboxylic acid bis (4-aminophenyl) ester, p-phenylene bis (p-aminobenzoate), bis (4-aminophenyl)-[1,1' -Biphenyl] -4,4'-dicarboxylate, [1,1'-biphenyl] -4,4'-diylbis (4-aminobenzoate), 4,4'-oxydianiline, 3,4'-oxy Dianiline, 3,3'-oxydianiline, bis (4-aminophenyl) sulfide, p-methylenebis (phenylenediamine), 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-) Aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexa Fluoropropane, bis (4-aminophenyl) sulfone, 3,3-bis ((aminophenoxy) phenyl) propane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (4-( 4-Aminophenoxy) diphenyl) sulfone, bis (4- (3-aminophenoxy) diphenyl) sulfone, octafluorobenzidine, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4 , 4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 9,9-bis (4-aminophenyl) fluorene, 4,4'-(spiro [fluoren-9,9'- Xanthene] -3', 6'-diylbis (oxy)) dianiline, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, 1,4-diaminocyclo Hexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylsik Lohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, Examples thereof include 1,4-diamino-2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane and derivatives thereof. Among these, p-phenylenediamine, m-tridine, 4,4'-oxydianiline, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 9,9-bis (4-aminophenyl) fluorene, 4,4'-(spiro [fluorene-9,9'-xanthene] -3', 6'-diylbis (oxy)) dianiline and the like are more preferable. These diamine components may be used alone or in combination of two or more.

When the tetracarboxylic acid component to be combined is not a tetracarboxylic acid component that gives a repeating unit represented by the chemical formula (1), the diamine component that gives another repeating unit is a repeating unit represented by the chemical formula (1). It may be a diamine component to be given, that is, TFMB.

The polyimide of the first embodiment of the present invention and the polyimide solution composition of the second embodiment of the present invention (hereinafter, also simply referred to as the polyimide of the present invention and the polyimide solution composition of the present invention) are, for example, , Can be manufactured as follows. However, the method for producing the polyimide of the present invention and the polyimide solution composition of the present invention is not limited to the following production methods.

In the polyimide solution composition of the present invention, the tetracarboxylic acid component such as tetracarboxylic acid dianhydride and the diamine component are substantially equimolar, preferably the molar ratio of the diamine component to the tetracarboxylic acid component [diamine component. The number of moles / the number of moles of the tetracarboxylic acid component] is preferably 0.90 to 1.10, and more preferably 0.95 to 1.05.

More specifically, the diamine component is dissolved in a solvent, and the tetracarboxylic acid component such as tetracarboxylic acid dianhydride is gradually added while stirring the solution, and if necessary, preferably at room temperature to 80 ° C. After stirring in the range of 0.5 to 30 hours, the temperature is raised and the imidization reaction is carried out to obtain a polyimide solution. Imidization reaction can also be carried out by immediately raising the temperature after adding the tetracarboxylic acid component. It is also possible to reverse the order of addition of the diamine component and the tetracarboxylic acid component, and it is also possible to add the diamine component and the tetracarboxylic acid component to the solvent at the same time.

The imidization method is not particularly limited, and known thermal imidization or chemical imidization methods can be preferably applied. For example, a solution containing a tetracarboxylic acid component such as tetracarboxylic acid dianhydride and a diamine component is placed at a temperature in the range of 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 150 to 250 ° C., and 0.5 to 72. The imidization reaction can be carried out by reacting the tetracarboxylic acid component and the diamine component with stirring for a time. In the case of chemical imidization, a chemical imidizing agent (an acid anhydride such as anhydrous acetic acid or an amine compound such as pyridine, isoquinolin, or triethylamine) is added to the reaction solution to carry out the reaction. If necessary, an imidization catalyst or the like may be added to the reaction solution to carry out the reaction.

Further, the imidization reaction may be carried out while removing the water generated during the reaction.

When the molar ratio of the tetracarboxylic acid component to the diamine component is excessive, a carboxylic acid derivative in an amount substantially corresponding to the excess molar number of the diamine component is added as necessary, and the tetracarboxylic acid component and the diamine component are added. The molar ratio can be brought close to the equivalent amount. The carboxylic acid derivative here is a tetracarboxylic acid that does not substantially increase the viscosity of the polyimide solution, that is, does not substantially participate in the extension of the molecular chain, or a tricarboxylic acid that functions as a terminal terminator and its anhydride, a dicarboxylic acid. And its anhydride and the like are suitable.

The solvent used when preparing the polyimide solution is, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethylsulfoxide, etc. Aprotonic solvent is preferable, and N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable, but any kind of solvent can be used as long as the raw material monomer component and the produced polyimide are dissolved. Since it can be used, it is not particularly limited to its structure. As the solvent, an amide solvent 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. System solvents, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like are preferably adopted. In addition, other common organic solvents such as phenol, o-cresol, butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran. , Dimethoxyethane, diethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methylisobutylketone, diisobutylketone, cyclopentanone, cyclohexanone, methylethylketone, acetone, butanol, ethanol, xylene, toluene, chlorbenzene, turpen, mineral spirit, petroleum Nafsa-based solvents and the like can also be used. The solvent may be used in combination of a plurality of types.

After performing the imidization reaction as described above, the obtained reaction solution is used as it is, or concentrated or diluted, and if necessary, additives and the like described below are added to obtain the polyimide solution composition of the present invention. Can be used. Alternatively, a soluble polyimide can be isolated from the obtained reaction solution, and the isolated polyimide can be added to a solvent to obtain the polyimide solution composition of the present invention. Isolation of the polyimide can be performed, for example, by dropping or mixing a reaction solution containing the obtained soluble polyimide in a poor solvent such as water to precipitate (reprecipitate) the polyimide.

The polyimide solution composition of the present invention contains at least a polyimide and a solvent, and the polyimide is 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, particularly, with respect to the total amount of the solvent and the polyimide. The ratio is preferably 20% by mass or more. If this concentration is too low, it may be difficult to control the film thickness of the polyimide film obtained, for example, when manufacturing a polyimide film. In general, it is preferable that the polyimide content is 60% by mass or less, preferably 50% by mass or less.

As the solvent of the polyimide solution composition of the present invention, there is no problem as long as the polyimide is dissolved, and the structure thereof is not particularly limited. Examples of the solvent of the polyimide solution composition include the same solvent as that used when preparing the above-mentioned polyimide solution, and the solvent used when preparing the polyimide solution is used as it is as the solvent of the polyimide solution composition. can do. Further, if necessary, the solvent may be removed from the polyimide solution composition prepared as described above, or the solvent may be added.

In the present invention, the logarithmic viscosity of the polyimide 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 0.4 dL. It is preferably / g or more, particularly preferably 0.5 dL / g or more. When the logarithmic viscosity is 0.2 dL / g or more, the obtained polyimide is excellent in mechanical strength and heat resistance.

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

The polyimide solution composition of the present invention contains, if necessary, antioxidants, fillers (inorganic particles such as silica), dyes, pigments, coupling agents such as silane coupling agents, primers, flame-retardant materials, and defoamers. It can contain an agent, a leveling agent, a rheology control agent (fluid auxiliary agent), a release agent and the like.

The polyimide of the present invention can be suitably obtained by removing the solvent from the polyimide solution composition prepared as described above. For example, a polyimide film / base material laminate can be produced by spreading and applying a polyimide solution composition on a base material and heating the polyimide solution composition on the base material to remove a 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 carried out in vacuum, in an inert gas such as nitrogen, or in air, but it is usually desirable to carry out the heat treatment in vacuum or in an inert gas. Then, the polyimide film can be manufactured by peeling the polyimide film formed on the substrate from the substrate.

Here, the base material is not particularly limited, and for example, a base material such as ceramic (glass, silicon, alumina), metal (copper, aluminum, stainless steel), and heat-resistant plastic film (polyimide film) can be used. In one embodiment, glass is preferable as the base material, and the polyimide film / glass base material laminate obtained by forming the polyimide film on the glass base material is preferably used for producing, for example, a substrate for a display. Be done.

Further, the polyimide solution composition is cast and applied on the substrate, the polyimide solution composition on the substrate is dried to the extent that it becomes self-supporting, and the obtained self-supporting film is peeled off from the substrate. The polyimide film can also be suitably produced by removing the solvent by heating the film with the edges fixed. The drying conditions for producing the self-supporting film can be appropriately determined, and for example, the polyimide solution composition may be dried on the substrate in a temperature range of about 50 to 300 ° C. The temperature of the heat treatment 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. Also in this method, the heat treatment can be carried out in vacuum, in an inert gas such as nitrogen, or in air, but it is usually desirable to carry out the heat treatment in vacuum or in an inert gas.

The form of the polyimide of the present invention is not limited to a film or a laminate of a polyimide film and another base material, and a coating film, a powder, beads, a molded body, a foam, or the like can be preferably mentioned. can.

The polyimide of the present invention thus obtained has a linear thermal expansion coefficient between 100 and 250 ° C., preferably 25 ppm / K or less, more preferably 20 ppm / K or less, when measured on a film having a thickness of 10 μm. Particularly preferably, it is 15 ppm / K or less. If the coefficient of linear thermal expansion is large, the difference in the coefficient of linear thermal expansion from that of a conductor such as metal is large, which may cause problems such as increased warpage when forming a circuit board. The coefficient of linear thermal expansion in the present invention is a value measured for a polyimide film having a film thickness of 10 μm under the conditions of a film width of 4 mm, a chuck distance of 15 mm, a tensile load of 2 g, and a temperature rise rate of 20 ° C./min. Therefore, the coefficient of linear thermal expansion tends to decrease as the film thickness increases.

The polyimide of the present invention also preferably has a light transmittance of preferably 80% or more, more preferably 83% or more when measured with a film having a thickness of 10 μm. When a polyimide film is used for a display application or the like, if the light transmittance is low, it is necessary to strengthen the light source, which may cause a problem that energy is applied. The light transmittance at a wavelength of 400 nm tends to decrease as the film thickness increases.

The polyimide of the present invention preferably has a haze of preferably 2% or less, more preferably 1.5% or less, and particularly preferably 1% or less when measured on a film having a thickness of 10 μm. When a polyimide film is used for a display application or the like, if the haze is high, light may be scattered and the image may be blurred. The haze tends to increase as the film thickness increases.

The film made of the polyimide of the present invention has a thickness of preferably 1 μm to 250 μm, more preferably 1 μm to 150 μm, still more preferably 1 μm to 100 μm, and particularly preferably 1 μm to 80 μm, although it depends on the application. When the polyimide film is used for light transmission, if the polyimide film is too thick, the light transmittance may decrease.

The polyimide film / base material laminate or the polyimide film obtained as described above can obtain a flexible conductive substrate by forming a conductive layer on one side or both sides thereof.

The flexible conductive substrate can be obtained, for example, by the following method. That is, as a first method, a conductive substance (metal or metal oxidation) is applied to the surface of the polyimide film by sputtering, vapor deposition, printing, etc. without peeling the polyimide film from the base material of the polyimide film / base material laminate. A conductive layer of a material, a conductive organic material, a conductive carbon, etc.) is formed to produce a conductive laminate of a conductive layer / polyimide film / base material. After that, if necessary, the conductive layer / polyimide film laminate can be peeled off from the substrate to obtain a transparent and flexible conductive substrate made of the conductive layer / polyimide film laminate.

The second method is to peel the polyimide film from the base material of the polyimide film / base material laminate to obtain a polyimide film, and on the surface of the polyimide film, a conductive substance (metal or metal oxide, conductive organic substance, A conductive layer (such as conductive carbon) is formed in the same manner as in the first method, and is a transparent and flexible conductive layer composed of a conductive layer / polyimide film laminate or a conductive layer / polyimide film / conductive layer laminate. A sex 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 and light adjustment are performed by sputtering, vapor deposition, gel-sol method, or the like. 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 inkjet method.

The substrate of the present invention thus obtained has a circuit of a conductive layer on the surface of a polyimide film made of the polyimide of the present invention, if necessary, via a gas barrier layer or an inorganic layer. This substrate is flexible, has excellent transparency, bendability, and heat resistance, and has an extremely low coefficient of linear thermal expansion, so that it is easy to form a fine circuit. Therefore, this substrate can be suitably used as a substrate for a display, 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 inkjet method, or the like to manufacture a flexible thin film transistor, and a liquid crystal element, an EL element, or a photoelectric device for a display device is manufactured. It is suitably used as an element.
Further, in the first method, after forming not only the conductive layer but also at least a part of the transistor and / or other elements and structures necessary for the device on the surface of the polyimide film / base material laminate. The substrate may be peeled off.

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

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

<Evaluation of polyimide solution>
[Imidization rate]
Tetramethylsilane was used as the internal standard material, dimethylsulfoxide _- d6 was used as the diluting solvent for the polyimide solution, and ¹ H-NMR measurement of the polyimide solution was performed with M-AL400 manufactured by JEOL Ltd., and the integrated value of the peak of the aromatic proton was measured. The imidization rate was calculated by the following formula (I) from the ratio of the integrated value of the peak of the amide proton and the peak.

Imidization rate (%) = {1- (Y / Z) × (1 / X)} × 100 (I)
X: Integrated value of amide proton peak / integrated value of aromatic proton peak when imidization rate is 0%, which is obtained from the amount of monomer charged Y: ¹ Integrated value of amide proton peak obtained from H-NMR measurement Z: ¹ Integrated value of aromatic proton peak obtained from H-NMR measurement

<Evaluation of polyimide film>
[400 nm light transmittance]
Using an ultraviolet-visible spectrophotometer / V-650DS (manufactured by JASCO Corporation), the light transmittance of a polyimide film having a film thickness of 10 μm and a size of 5 cm square was measured at a wavelength of 400 nm.

[Haze]
Using a turbidity meter / NDH2000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.), the haze of a polyimide film having a film thickness of 10 μm and a size of 5 cm square was measured according to the JIS K7136 standard.

[Coefficient of linear thermal expansion (CTE)]
A polyimide film with a thickness of 10 μm is cut into strips with a width of 4 mm to make test pieces, and TMA / SS6100 (manufactured by SII Nanotechnology Co., Ltd.) is used. The temperature was raised to 500 ° C. in minutes. From the obtained TMA curve, the coefficient of linear thermal expansion from 100 ° C to 250 ° C was obtained.

[Tension modulus, fracture point elongation, fracture point stress]
The polyimide film was punched into a dumbbell shape of IEC-540 (S) standard to make a test piece (width: 4 mm), and using ORIENTEC's TENSILON, the chuck spacing was 30 mm, the tensile speed was 2 mm / min, and the initial tensile elastic modulus. , Break point elongation and break point stress were measured.

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) fluorene 4,4'-ODA: 4,4'-oxydianiline [purity: 99.9% (GC analysis)]
BABP: 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 acid dianhydride PMDA-H: 1, 2, , 4,5-Cyclohexanetetracarboxylic acid dianhydride [Purity: 99.9% (GC analysis)]

[solvent]
GBL: γ-Butyrolactone DMAc: N, N-dimethylacetamide

[Example 1]
TFMB 7.00 g (21.9 mmol) and BAFL 6.23 g (17.9 mmol) were placed in a reaction vessel substituted with nitrogen gas, and a mixed solvent of DMAc and GBL (DMAc: GBL = 1: 2 (mass ratio)) was placed. )) Is added in an amount of 95.44 g (DMAc is 31.81 g and GBL is 63.63 g) so that the total mass of the charged monomer (total of diamine component and carboxylic acid component) is 23% by mass, and the mixture is stirred at room temperature for 1 hour. bottom. 15.28 g (39.7 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 450 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent to obtain a colorless and transparent polyimide film / glass laminate. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 2]
TFMB 9.00 g (28.1 mmol) and BAFL 6.53 g (18.7 mmol) were placed in a reaction vessel substituted with nitrogen gas, and DMAc was added to the total mass of the charged monomer (total of diamine component and carboxylic acid component). 112.26 g was added in an amount of 23% by mass, and the mixture was stirred at room temperature for 1 hour. 18.00 g (46.8 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 430 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent to obtain a colorless and transparent polyimide film / glass laminate. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 3]
TFMB 9.00 g (28.1 mmol) and BAFL 4.20 g (12.0 mmol) were placed in a reaction vessel substituted with nitrogen gas, and DMAc was added to the total mass of the charged monomer (total of diamine component and carboxylic acid component). 95.85 g was added in an amount of 23% by mass, and the mixture was stirred at room temperature for 1 hour. 15.43 g (40.2 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 410 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 4]
10.00 g (31.2 mmol) of TFMB and 2.72 g (7.8 mmol) of BAFL were placed in a reaction vessel substituted with nitrogen gas, and DMAc was added to the total mass of the charged monomer (total of diamine component and carboxylic acid component). 92.82 g was added in an amount of 23% by mass, and the mixture was stirred at room temperature for 1 hour. 15.00 g (39.0 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 410 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 5]
10.00 g (31.2 mmol) of TFMB and 1.20 g (3.5 mmol) of BAFL were placed in a reaction vessel substituted with nitrogen gas, and DMAc was added to the total mass of the charged monomer (total of diamine component and carboxylic acid component). 82.18 g was added in an amount of 23% by mass, and the mixture was stirred at room temperature for 1 hour. 13.34 g (34.7 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 410 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 6]
40.00 g (124.9 mmol) of TFMB was placed in a reaction vessel substituted with nitrogen gas, and DMAc was added to 264.04 g in an amount such that the total mass of the charged monomers (total of diamine component and carboxylic acid component) was 25% by mass. Was added, and the mixture was stirred at room temperature for 1 hour. 48.01 g (124.9 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 410 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 7]
TFMB 8.00 g (25.0 mmol), BAFL 2.90 g (8.3 mmol) and 4,4'-ODA 1.67 g (8.3 millimoles) were placed in a reaction vessel substituted with nitrogen gas, and DMAc was placed. Was added with an amount of 95.66 g having a total mass of charged monomers (total of diamine component and carboxylic acid component) of 23% by mass, and the mixture was stirred at room temperature for 1 hour. 16.00 g (41.6 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 410 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 8]
In a reaction vessel substituted with nitrogen gas, 8.00 g (25.0 mmol) of TFMB, 4.35 g (12.5 mmol) of BAFL and 1.53 g (4.2 millimol) of BABP were placed, and DMAc was added to the total monomer. 100.07 g of an amount having a mass (total of diamine component and carboxylic acid component) of 23% by mass was added, and the mixture was stirred at room temperature for 1 hour. 16.00 g (41.6 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 410 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 9]
10.00 g (31.2 mmol) of TFMB and 4.66 g (13.4 mmol) of BAFL were placed in a reaction vessel substituted with nitrogen gas, and a mixed solvent of DMAc and GBL (DMAc: GBL = 1: 2 (weight ratio)) was placed. )) To Add 90.06 g (DMAc: 30.02 g and GBL: 60.04 g) in an amount such that the total mass of the charged monomer (total of diamine component and carboxylic acid component) is 25% by mass, and stir at room temperature for 1 hour. bottom. 12.86 g (33.5 mmol) of CpODA and 2.5 g (11.1 mmol) of PMDA-H were gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 410 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Example 10]
10.00 g (31.2 mmol) of TFMB and 3.91 g (13.4 mmol) of TPE-Q were placed in a reaction vessel substituted with nitrogen gas, and a mixed solvent of DMAc and GBL (DMAc: GBP = 1: 2 (DMAc: GBP = 1: 2). Add 93.18 g (31.06 g of DMAc and 62.12 g of GBL) in an amount that makes the total mass of the charged monomer (total of diamine component and carboxylic acid component) 25% by mass, and add 1 at room temperature. Stirred for hours. 17.15 g (44.6 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 370 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

[Comparative Example 1]
TFMB 7.00 g (21.9 mmol) and BAFL 7.62 g (21.9 mmol) were placed in a reaction vessel replaced with nitrogen gas, and DMAc was added to the total mass of the charged monomer (total of diamine component and carboxylic acid component). 94.26 g was added in an amount of 25% by mass, and the mixture was stirred at room temperature for 1 hour. 16.80 g (43.7 mmol) of CpODA was gradually added to this solution. The mixture was stirred at 70 ° C. for 3 hours and 160 ° C. for 7 hours to obtain a uniform and viscous polyimide solution. The imidization rate of the obtained polyimide solution was 95% or more.

The polyimide solution was applied to a glass substrate and heated from room temperature to 410 ° C. on the glass substrate as it was under a nitrogen atmosphere (oxygen concentration of 200 ppm or less) to remove the solvent, and a colorless and transparent polyimide film / glass laminate was obtained. Then, the obtained polyimide film / glass laminate was immersed in water, peeled off, and dried to obtain a polyimide film having a film thickness of 10 μm.

Table 1 shows the results of measuring the characteristics of this polyimide film.

INDUSTRIAL APPLICABILITY 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 having high transparency and an extremely low coefficient of linear thermal expansion. Further, according to the present invention, it is possible to provide a polyimide solution composition capable of obtaining a polyimide having high transparency and an extremely low coefficient of linear thermal expansion. The polyimide of the present invention and the polyimide obtained from the polyimide solution composition of the present invention have high transparency and a low coefficient of linear thermal expansion, and it is easy to form a fine circuit. It can be suitably used for forming.

Claims (11)

A polyimide containing more than 50 mol% of the repeating units represented by the following chemical formula (1) with respect to all the repeating units.
When measured with a film with a thickness of 10 μm,
The coefficient of linear thermal expansion between 100 and 250 ° C. is 25 ppm / K or less, and
A polyimide characterized by having a light transmittance of 80% or more at a wavelength of 400 nm (provided that the polyimide has a light transmittance of 80% or more.
(A)
Excluding polyimide obtained by using a diamine component containing a diamine represented by the following formula (1-1);

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are independent halogen atoms and carbon sources, respectively.
Represents an alkyl group having 1 to 5 children or an alkoxy group having 1 to 5 carbon atoms.
R ₆ and R ₇ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.
a, b, d and e each independently represent an integer from 0 to 4, and
c represents an integer of 0 to 2. )
and,
(B)
Norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'', 6,6''-tetracarboxylic acid dianhydride giving the repeating unit of formula (1) The following conditions (1a) and (1b) are satisfied for (hereinafter referred to as CpODA) and 2,2'-bis (trifluoromethyl) benzidine (hereinafter referred to as TFMB).
(1a) When the polyimide is prepared from 100 mol% CpODA tetracarboxylic acid dianhydride and 100 mol% TFMB diamine compound, the proportion of CpODA isomers is trans-exo-end isomer and cis-exo-end isomer. Excluding polyimides with a total body volume of 41.5 mol% or more;
(1b) When the polyimide is prepared from a tetracarboxylic acid dianhydride having a CpODA of less than 100 mol% and a diamine compound having a TFMB of 100 mol%, the tetracarboxylic acid dianhydride other than CpODA is 3,3', 4,4'-. Excludes polyimides consisting of biphenyltetracarboxylic acid dianhydride and / or pyromellitic acid dianhydride and 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride. ) .

Polyimide containing more than 50 mol% of the repeating unit represented by the following chemical formula (1) with respect to all the repeating units and having an imidization ratio of more than 90% is dissolved in the solvent.
The solvent is N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ- From butyrolactone, ethylene carbonate, propylene carbonate, triethylene glycol, m-cresol, p-cresol, 3-chlorophenol, 4-chlorophenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, and dimethyl sulfoxide A polyimide solution composition characterized by being one or more selected from the group of
(A)
Does not contain polyimide obtained by using a diamine component containing a diamine represented by the following formula (1-1);

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are independent halogen atoms and carbon sources, respectively.
Represents an alkyl group having 1 to 5 children or an alkoxy group having 1 to 5 carbon atoms.
R ₆ and R ₇ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms.
a, b, d and e each independently represent an integer from 0 to 4, and
c represents an integer of 0 to 2. )
and,
(B)
The following conditions (2a) and (2b) are satisfied for CpODA and TFMB that give the repeating unit of the formula (1).
(2a) When the polyimide is prepared from 100 mol% CpODA tetracarboxylic acid dianhydride and 100 mol% TFMB diamine compound, the proportion of CpODA isomers is trans-exo-end isomer and cis-exo-end isomer. Does not contain polyimides with a total body mass of 83.1 mol% or more;
(2b) When the polyimide is prepared from a tetracarboxylic acid dianhydride having a CpODA of less than 100 mol% and a diamine compound having a TFMB of 100 mol%, the tetracarboxylic acid dianhydride other than CpODA is 3,3', 4,4'-. It does not contain a polyimide consisting of biphenyltetracarboxylic acid dianhydride and / or pyromellitic acid dianhydride and 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride. ) .

A polyimide obtained by removing a solvent from the polyimide solution composition according to claim 2 (provided that the polyimide is obtained.
(3a) When the polyimide is prepared from 100 mol% CpODA tetracarboxylic acid dianhydride and 100 mol% TFMB diamine compound, the proportion of CpODA isomers is trans-exo-end isomer and cis-exo-end. Excluding polyimide having a total amount of isomers of 41.5 mol% or more. ) . A polyimide film obtained by removing a solvent from the polyimide solution composition according to claim 2 (provided that the polyimide film is obtained.
(4a) When the polyimide is prepared from 100 mol% CpODA tetracarboxylic acid dianhydride and 100 mol% TFMB diamine compound, the proportion of CpODA isomers is trans-exo-end isomer and cis-exo-end. Excluding polyimide having a total amount of isomers of 41.5 mol% or more. ) . The claim is characterized in that the linear thermal expansion coefficient between 100 and 250 ° C. is 25 ppm / K or less and the light transmittance at a wavelength of 400 nm is 80% or more when the film thickness is measured at 10 μm. The polyimide according to 3. The claim is characterized in that the linear thermal expansion coefficient between 100 and 250 ° C. is 25 ppm / K or less and the light transmittance at a wavelength of 400 nm is 80% or more when the film thickness is measured at 10 μm. 4. The polyimide film according to 4. A laminate comprising the polyimide according to claim 1 or the polyimide film according to claim 4 or 6 formed on a glass substrate. A substrate for a display, a touch panel, or a solar cell, which comprises the polyimide film according to claim 1 or 3, or the polyimide film according to claim 4 or 6 . The step of applying the polyimide solution composition according to claim 2 to a substrate, and
A method for producing a polyimide film / base material laminate, which comprises a step of heating the polyimide solution composition on a base material. The step of applying the polyimide solution composition according to claim 2 to a substrate, and
The step of heating the polyimide solution composition on the substrate and
A method for producing a polyimide film, which comprises a step of peeling a polyimide film formed on a substrate from the substrate. The step of applying the polyimide solution composition according to claim 2 to a substrate, and
The step of drying the polyimide solution composition to obtain a self-supporting film, and
The step of peeling the self-supporting film from the substrate and heating it,
A method for manufacturing a polyimide film containing.