TWI695855B - Polyimide precursor, resin composition and resin film manufacturing method - Google Patents

Abstract

{式中，X₁ 表示碳數4～32之四價之基；R₁ 、R₂ 、R₃ 分別獨立表示碳數1～20之一價之有機基；n表示0或1；並且a、b及c為0～4之整數}；及 下述通式(2)所表示之結構單元M：

{式中，X₂ 表示碳數4～32之四價之基}。The present invention is a polyimide precursor, which is (a1) a polyimide precursor, which is 1/99≦(mole number of structural unit L/mole number of structural unit M)≦99/1 Contains: Structural unit L represented by the following general formula (1):

{In the formula, X ₁ represents a tetravalent group with a carbon number of 4 to 32; R ₁ , R ₂ , and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b and c are integers from 0 to 4}; and the structural unit M represented by the following general formula (2):

{In the formula, X ₂ represents a tetravalent base having 4 to 32 carbon atoms}.

Description

Polyimide precursor, resin composition and resin film manufacturing method

The present invention relates to, for example, a method for manufacturing a polyimide precursor, a resin composition, and a resin film used in the manufacture of substrates for flexible devices.

Generally, a film of polyimide resin is used as a resin film in applications requiring high heat resistance. Common polyimide resins are produced by solution polymerization of aromatic carboxylic acid dianhydride and aromatic diamine to produce a polyimide precursor, which is then thermally imidized at high temperature or using a catalyst High heat-resistant resin manufactured by chemical imidization.

Polyimide resin is an insoluble and infusible super heat-resistant resin with excellent characteristics such as heat-resistant oxidation, heat resistance, radiation resistance, low temperature resistance, and chemical resistance. Therefore, polyimide resin is used in a wide range of fields including electronic materials. Examples of the application of polyimide resin in the field of electronic materials include, for example, insulating coating agents, insulating films, protective films for semiconductors, and TFT-LCD (Thin film transistor-liquid crystal display). The electrode protection film, etc. Recently, research is being conducted to replace the glass substrate previously used in the field of display materials as a colorless transparent flexible substrate using its lightness and flexibility.

In the case of manufacturing a polyimide resin film as a flexible substrate, a composition containing a polyimide precursor is coated on an appropriate support to form a coating film, and then heat-treated to imide the polyimide, thereby A polyimide resin film was obtained. As the support, for example, glass, silicon, silicon nitride, silicon oxide, metal, or the like is used. When manufacturing a laminate having a polyimide film on such a support, in order to dry and polyimide the polyimide precursor, a high temperature of 250°C or higher is required Of heat treatment. By this heat treatment, residual stress is generated in the laminate, and serious problems such as warpage and peeling are caused. The reason is that the thermal expansion coefficient of polyimide is larger than that of the material constituting the support.

As a polyimide material having a small thermal expansion coefficient, the most well-known is polyimide formed from 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine. Although it depends on the film thickness and production conditions, it is reported that this polyimide film shows a very low linear thermal expansion coefficient (Non-Patent Document 1).

In addition, it is reported that polyimide having an ester structure in the molecular chain has moderate linearity and rigidity, and therefore shows a low coefficient of linear thermal expansion (Patent Document 1).

However, for the conventional polyimide resin containing the polyimide described in the above literature, due to the higher aromatic ring density, the coloration is brown or yellow, so the light transmittance in the visible light region is low, Therefore, it is difficult to use in fields requiring transparency. For example, the above-mentioned non-patent document 1 obtained from 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine has a polyimide-based film with a thickness of 10 μm and a yellowness (YI value) of up to 40 The above is insufficient in terms of transparency.

Regarding the yellowness of the film, for example, it is known that polyimide using a monomer having a fluorine atom shows extremely low yellowness (Patent Document 2).

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Specification of Japanese Patent No. 4627297

[Patent Document 2] Japanese Patent Special Publication No. 2010-538103

[Patent Document 3] Specification of Japanese Patent No. 3079867

[Non-patent literature]

[Non-Patent Document 1] Latest Polyimide Japan Polyimide Research Society Editor NTS

However, in order to use the polyimide resin as a colorless transparent flexible substrate, in addition to transparency, excellent mechanical properties such as elongation and breaking strength are also required. Especially recently, the device type accompanying TFT (thin-film transistor) has become LTPS (Low Temperature Poly-silicon) (low temperature poly-silicon) (low-temperature poly-silicon TFT), and it is expected that a device that can perform the above-mentioned effects even if it exceeds the previous thermal history Physical film.

However, the physical properties of the well-known transparent polyimide are insufficient for use as a heat-resistant colorless transparent substrate for displays.

Furthermore, it has been confirmed by the inventors that although the polyimide resin described in Patent Document 1 shows a low coefficient of linear thermal expansion, the yellowness (YI value) of the polyimide resin film after peeling is large. In addition, the residual stress is high, the elongation is low, and the fracture strength is low.

Regarding the yellowness, it can be seen that the polyimide film described in Patent Document 2 exhibits a low yellowness in the temperature range of about 300°C, but the yellowness (YI value) significantly deteriorates in the high-temperature range of 400°C or higher. .

In addition, as a polyimide having a reduced linear expansion coefficient, a polyimide containing 4,4'-diaminodiphenyl ether and 4,4'-diaminodiphenyl ester is disclosed (Patent Document 3) .

However, as confirmed by the present inventors, the polyimide resin described in Patent Document 3 is very brittle for use as a flexible substrate, and there is room for improvement in yellowness at high temperatures.

The present invention has been completed in view of the problems described above. Therefore, the object of the present invention is to provide a polyimide resin film with low residual stress, low warpage, low yellowness (YI value), and high elongation, and a method for manufacturing the same.

The present invention is as follows.

[1]

A polyimide precursor, characterized in that it is (a1) a polyimide precursor, which is 1/99≦(mole number of structural unit L/mole number of structural unit M)≦99/1 Contains: Structural unit L represented by the following general formula (1):

{In the formula, X ₁ represents a tetravalent group with a carbon number of 4 to 32; R ₁ , R ₂ and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b and c are integers from 0 to 4}; and the structural unit M represented by the following general formula (2):

{In the formula, X ₂ represents a tetravalent group with a carbon number of 4 to 32; Y is at least one selected from the group consisting of the following general formulas (3), (4) and (5)},

{In the formula, R ₄ ~R ₁₁ independently represent a monovalent organic group with a carbon number of 1~20; d~k is an integer of 0~4}.

[2]

The polyimide precursor as in [1], wherein n in the above general formula (1) is 0.

[3]

The polyimide precursor as in [1] or [2], wherein Y in the above general formula (2) is the general formula (3).

[4]

The polyimide precursor as in [1] or [2], wherein Y in the above general formula (2) is the general formula (4).

[5]

The polyimide precursor as in [1] or [2], wherein Y in the above general formula (2) is the general formula (5).

[6]

A polyimide precursor, characterized in that it is (a2) a polyimide precursor, which contains a structural unit represented by the following general formula (10): [Chem 6]

Moreover, the weight average molecular weight is 30,000 or more and 300,000 or less, {wherein, X ₃ represents a source selected from the group consisting of 4,4'-oxydiphthalic dianhydride (ODPA) and biphenyltetracarboxylic dianhydride (BPDA) At least one tetravalent group in the group formed; R ₁ , R ₂ , and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b, and c are Integer of 0~4}.

[7]

For example, the polyimide precursor of [6], wherein the content of the above-mentioned (a2) polyimide precursor has a weight average molecular weight of less than 1,000 molecules and the content is less than 5 mass%.

[8]

The polyimide precursor as in [6] or [7], wherein n in the general formula (10) is 0.

[9]

The polyimide precursor according to any one of [1] to [5], wherein the above X _1, X ₂ are derived from pyromellitic dianhydride (PMDA), 4,4′-oxydi-ortho A tetravalent organic group of at least one of the group consisting of phthalic dianhydride (ODPA) and biphenyltetracarboxylic dianhydride (BPDA).

[10]

A resin composition characterized in that it contains the polyimide precursor according to any one of [1] to [9] and (b) an organic solvent.

[11]

The resin composition as described in [10], which further contains a resin selected from the group consisting of (c) surfactant and (d) alkoxy silicon At least one of the groups consisting of alkane compounds.

[12]

A polyimide characterized in that it contains a structural unit represented by the following general formula (11):

{In the formula, X ₁ and X ₂ represent a tetravalent group with a carbon number of 4 to 32; R ₁ , R ₂ and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; And a, b, and c are integers from 0 to 4; Y is at least one selected from the group consisting of the following general formulas (3), (4), and (5); l, m independently represent 1 or more Integer, satisfying 0.01≦l/(l+m)≦0.99},

[化10]

{In the formula, R ₄ ~R ₁₁ independently represent a monovalent organic group with a carbon number of 1~20; d~k is an integer of 0~4}.

[13]

A polyimide characterized in that it contains a structural unit represented by the following general formula (12):

{In the formula, X ₃ represents a tetravalent derived from at least one selected from the group consisting of 4,4'-oxydiphthalic dianhydride (ODPA) and biphenyltetracarboxylic dianhydride (BPDA) Radicals; R ₁ , R ₂ , R ₃ independently represent a monovalent organic group with a carbon number of 1-20; n represents 0 or 1; and a, b, and c are integers of 0-4}, and the elongation is 15 %the above.

[14]

A method of manufacturing a resin film, characterized in that it includes the steps of: forming a coating film by coating a resin composition such as [10] or [11] on the surface of a support; by applying the support And the step of heating the coating film to form a polyimide resin film that is polyimide precursor contained in the coating film to form a polyimide resin film; and peeling the polyimide resin film from the support A step of.

[15]

The method for producing a resin film according to [14], wherein before the step of peeling the polyimide resin film from the support, a step of irradiating the laser from the side of the support is performed.

[16]

A method for manufacturing a laminate, characterized in that it includes the steps of forming a coating film by coating a resin composition such as [10] or [11] on the surface of a support; and by applying the above support The step of heating the body and the above coating film to imide the polyimide precursor contained in the coating film to form a polyimide resin film.

[17]

A method for manufacturing a display substrate, characterized in that it includes the steps of: forming a coating film by coating a resin composition such as [10] or [11] on the surface of a support; by applying the support And the above-mentioned coating film is heated to form a polyimide resin film containing polyimide precursor imidized in the coating film to form a polyimide resin film; forming an element or a circuit on the polyimide resin film Step; and the step of peeling the polyimide resin film formed with the element or circuit from the support.

[18]

A polyimide film for displays, characterized in that it contains a polyimide represented by the following general formula (12): [化12]

{In the formula, X ₃ is at least one selected from the group consisting of 4,4'-oxydiphthalic dianhydride (ODPA) and biphenyltetracarboxylic dianhydride (BPDA), R ₁ and R ₂ , R ₃ independently represents a monovalent organic group having 1 to 20 carbon atoms; n represents 0 or 1; and a, b, and c are integers of 0 to 4}.

[19]

A laminated body characterized by comprising a polyimide film layer and a low-temperature polysilicon TFT layer, the polyimide film layer containing a polyimide represented by the following general formula (13):

{In the formula, X ₁ represents a tetravalent group with a carbon number of 4 to 32; R ₁ , R ₂ and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b and c are integers from 0 to 4}.

[20]

A polyimide film, characterized in that the yellowness of the film with a thickness of 10 microns after heating above 400°C is 20 or less, the absorbance at 308 nm when the film thickness is 0.1 microns is 0.6 or more and 2.0 or less, and the elongation is 15 %the above.

[twenty one]

A resin composition characterized by comprising: (a) a polyimide precursor represented by the following general formula (1), (b) an organic solvent, and selected from (c) a surfactant and (d) At least one of the group consisting of alkoxysilane compounds,

{In the formula, X ₁ represents a tetravalent group with a carbon number of 4 to 32; R ₁ , R ₂ and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b and c are integers from 0 to 4}.

The polyimide film obtained from the polyimide precursor and resin composition of the present invention has low residual stress, less warpage, less yellowness (YI value), and higher elongation.

2a: Lower substrate

2b: Sealed substrate

25: Organic EL substrate

251: partition

252: Lower electrode

253: Hole transport layer

254: Luminous layer

255: upper electrode

256: amorphous silicon layer

257: contact hole

258: Interlayer insulating film

259: Lower electrode

261: Hollow Department

FIG. 1 is a diagram showing the structure of an organic EL (Electroluminescence) substrate produced in Examples and Comparative Examples.

Hereinafter, an exemplary embodiment of the present invention (hereinafter simply referred to as "embodiment") will be described in detail. Furthermore, the present invention is not limited by the following embodiments, and can be carried out within the scope of the gist Various changes are implemented. In addition, unless otherwise specified, the characteristic value described in the present invention refers to a value measured by the method described in the item of [Example] or the method understood by the manufacturer as the same method.

<resin composition>

The resin composition provided in one aspect of the present invention contains (a) a polyimide precursor and (b) an organic solvent.

Hereinafter, each component will be described in order.

[Polyimide precursor]

The polyimide precursor system as the first aspect of the present embodiment is a polyimide precursor having the following characteristics: (a1) a polyimide precursor, which is 1/99≦(the structural unit L Number of ears/mole number of structural unit M)≦99/1 Contains: Structural unit L represented by the following general formula (1):

{In the formula, X ₁ represents a tetravalent base with a carbon number of 4 to 32. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1. And a, b and c are integers from 0 to 4}; and the structural unit M represented by the following general formula (2): [Chem 16]

{In the formula, X ₂ represents a tetravalent base with a carbon number of 4 to 32. Y is at least one selected from the group consisting of the following general formulas (3), (4) and (5)}.

{In the formula, R ₄ to R ₁₁ independently represent a monovalent organic group having 1 to 20 carbon atoms. d~k is an integer from 0 to 4}

The polyimide precursor system of the first aspect of the present embodiment has low residual stress, less warpage, less yellowness (YI value) and higher elongation when the polyimide film is formed. Also, the first of this implementation When the polyimide precursor system of the aspect is made into a polyimide film, the yellowness (YI value) in the high-temperature region is small.

Here, R ₁ to R ₃ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, and alkoxy groups such as methoxy and ethoxy groups. Among them, from the viewpoint of YI in a high-temperature region, a methyl group is preferred.

Here, a, b, c, and d are not limited as long as they are integers from 0 to 4. Among them, from the viewpoint of YI and residual stress, an integer of 0 to 2 is preferable, and from the viewpoint of YI in a high-temperature region, 0 is particularly preferable.

Here, n is 0 or 1. Among them, from the viewpoint of YI in the high-temperature region, it is preferably 0.

In addition, the lower limit of the molar ratio of the structural unit L to the structural unit M (the number of moles of the structural unit L/the number of moles of the structural unit M) can be 5/95, 10/90, or 20/ 80 can also be 30/70 or 40/60. The upper limit of the molar ratio of the structural unit L to the structural unit M (the molar number of the structural unit L/the molar number of the structural unit M) can be 95/5, 90/10, or 80/20, It can also be 70/30 or 60/40.

X ₁ and X ₂ are independently a four-valent base with a carbon number of 4 to 32, and may be the same or different. The tetravalent organic group derived from the following tetracarboxylic dianhydride can be exemplified.

Specific examples of the tetracarboxylic dianhydride include aromatic tetracarboxylic dianhydride having 8 to 36 carbon atoms, aliphatic tetracarboxylic dianhydride having 6 to 36 carbon atoms and 6 to 6 carbon atoms. 36 compounds in alicyclic tetracarboxylic dianhydride. Among them, from the viewpoint of yellowness in a high-temperature region, an aromatic tetracarboxylic dianhydride having 8 to 36 carbon atoms is preferred. The carbon number here also includes the carbon number contained in the carboxyl group.

More specifically, the aromatic tetracarboxylic dianhydride having 8 to 36 carbon atoms may be exemplified by 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (hereinafter also referred to as 6FDA ), 5-(2,5-two sides Oxytetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2-dicarboxylic anhydride, pyromellitic dianhydride (hereinafter also referred to as PMDA), 1,2,3,4-benzene Tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone tetracarboxylic dianhydride, 3,3' ,4,4'-biphenyltetracarboxylic dianhydride (hereinafter also referred to as BPDA), 3,3',4,4'-diphenyl ash tetracarboxylic dianhydride, 2,2',3,3' -Biphenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylene-4,4'-diphthalic dianhydride, 2,2 -Propylene-4,4'-diphthalic dianhydride, 1,2-ethylidene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4 '-Diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic acid Formic dianhydride, 4,4'-oxydiphthalic dianhydride (hereinafter also referred to as ODPA), p-phenylene bis (trimellitic anhydride) (hereinafter also referred to as TAHQ), thio-4,4 '-Diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis(3,4-dicarboxyphenyl)phthalic anhydride, 1,3- Bis(3,4-dicarboxyphenoxy)phthalic anhydride, 1,4-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 1,3-bis[2-(3,4-bis Carboxyphenyl)-2-propyl]phthalic anhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]phthalic anhydride, bis[3-(3,4 -Dicarboxyphenoxy)phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-di Carboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy) Dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisilazane dianhydride, 2,3,6,7-naphthalene Tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic dianhydride , 2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrene tetracarboxylic dianhydride, etc.

Examples of the aliphatic tetracarboxylic dianhydride having 6 to 50 carbon atoms include, for example, ethylidene tetracarboxylic dianhydride, 1,2,3,4-butane tetracarboxylic dianhydride, etc. The carbon number is Examples of 6-36 alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutane tetracarboxylic dianhydride, cyclopentane tetracarboxylic dianhydride, and cyclohexane-1,2. ,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride (hereinafter referred to as CHDA), 3,3',4,4'-bicyclohexyltetracarboxylic acid Acid dianhydride, carbonyl -4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,2-ethylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylene-4,4'-bis(cyclohexane-1 ,2-dicarboxylic acid) dianhydride, 2,2-propylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis( (Cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis (Cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, rel-[1S,5R ,6R]-3-oxabicyclo[3,2,1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 4-(2 ,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, ethylene glycol-bis-(3,4-dicarboxylic anhydride phenyl) Ether etc.

From the viewpoint of the balance of CTE (Coefficient of thermal expansion), chemical resistance, Tg (Glass Transition Temperature) and yellowness in a high temperature region, PMDA, BPDA, TAHQ, ODPA, more preferably BPDA, TAHQ.

The polyimide precursor of the embodiment can be made into a polyimide amide imide precursor by using a dicarboxylic acid in addition to the above-mentioned tetracarboxylic dianhydride within the range that does not impair its performance. By using this precursor, various properties such as mechanical elongation increase, glass transition temperature increase, and yellowness decrease can be adjusted. Examples of such dicarboxylic acids include dicarboxylic acids having an aromatic ring and alicyclic dicarboxylic acids. Particularly preferred is at least one compound selected from the group consisting of aromatic dicarboxylic acids having 8 to 36 carbon atoms and alicyclic dicarboxylic acids having 6 to 34 carbon atoms. The carbon number here also includes the carbon number contained in the carboxyl group.

Among these, dicarboxylic acids having aromatic rings are preferred.

Specifically, for example, isophthalic acid, terephthalic acid, 4,4'-biphenyl dicarboxylic acid, 3,4'-biphenyl dicarboxylic acid, 3,3'-biphenyl dicarboxylic acid , 1,4-naphthalene dicarboxylic acid, 2,3-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-sulfonyl dibenzoic acid, 3 ,4'-sulfonyl bisbenzoic acid, 3,3'- Sulfonyl bisbenzoic acid, 4,4'-oxybisbenzoic acid, 3,4'-oxybisbenzoic acid, 3,3'-oxybisbenzoic acid, 2,2-bis(4-carboxybenzene Group) propane, 2,2-bis(3-carboxyphenyl)propane, 2,2'-dimethyl-4,4'-biphenyldicarboxylic acid, 3,3'-dimethyl-4,4 '-Biphenyldicarboxylic acid, 2,2'-dimethyl-3,3'-biphenyldicarboxylic acid, 9,9-bis(4-(4-carboxyphenoxy)phenyl) stilbene, 9 ,9-bis(4-(3-carboxyphenoxy)phenyl) stilbene, 4,4'-bis(4-carboxyphenoxy)biphenyl, 4,4'-bis(3-carboxyphenoxy) ) Biphenyl, 3,4'-bis(4-carboxyphenoxy) biphenyl, 3,4'-bis(3-carboxyphenoxy) biphenyl, 3,3'-bis(4-carboxyphenoxy) Group) biphenyl, 3,3'-bis(3-carboxyphenoxy)biphenyl, 4,4'-bis(4-carboxyphenoxy)-p-terphenyl, 4,4'-bis(4- Carboxyphenoxy)-metatriphenyl, 3,4'-bis(4-carboxyphenoxy)-p-terphenyl, 3,3'-bis(4-carboxyphenoxy)-p-terphenyl, 3 ,4'-bis(4-carboxyphenoxy)-metatriphenyl, 3,3'-bis(4-carboxyphenoxy)-metatriphenyl, 4,4'-bis(3-carboxybenzene Oxy)-p-terphenyl, 4,4'-bis(3-carboxyphenoxy)-m-terphenyl, 3,4'-bis(3-carboxyphenoxy)-p-terphenyl, 3,3 '-Bis(3-carboxyphenoxy)-p-terphenyl, 3,4'-bis(3-carboxyphenoxy)-metatriphenyl, 3,3'-bis(3-carboxyphenoxy) -Metatriphenyl, 1,1-cyclobutane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid, 4,4'-benzophenone dicarboxylic acid Acid, 1,3-phenylene diacetic acid, 1,4-phenylene diacetic acid, etc.; and 5-aminoisophthalic acid derivatives described in International Publication No. 2005/068535 pamphlet, etc. In the case of actually copolymerizing these dicarboxylic acids into a polymer, it can also be used in the form of acetyl chloride and active ester derived from thiosulfide and the like.

The weight average molecular weight (Mw) of the polyimide precursor of this embodiment is preferably 10,000 to 300,000, and particularly preferably 30,000 to 200,000. If the weight average molecular weight is greater than 10,000, the mechanical properties such as elongation and breaking strength are excellent, the residual stress is low, and the YI becomes low. If the weight average molecular weight is less than 300,000, it is easy to control the weight average molecular weight during the synthesis of polyamic acid, a resin composition with a moderate viscosity can be obtained, and the coating properties of the resin composition become good. In the present invention, the weight average molecular weight system uses gel permeation chromatography (hereinafter also referred to as GPC) to standard polystyrene The value obtained in the form of a converted value.

In the polyimide precursor of the present embodiment, the content of molecules with a molecular weight of less than 1,000 is preferably less than 5 mass% relative to the total amount of polyimide precursor, and more preferably less than 1 mass%. The residual stress of the polyimide film formed from the resin composition obtained by using such a polyimide precursor becomes low, and the haze (Haze) of the inorganic film formed on the polyimide film becomes A low viewpoint is better.

The content of molecules with a molecular weight of less than 1,000 relative to the total amount of polyimide precursor can be calculated from the peak area obtained by GPC measurement using a solution in which the polyimide precursor is dissolved.

As the diamine used for the structural unit represented by the general formula (1) of this embodiment, the diamine represented by the following general formula (6) can be exemplified.

(In the formula, R ₁ , R ₂ , and R ₃ independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1. and a, b, and c are integers of 0 to 4)

Examples of R ₁ and R ₂ include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, and alkoxy groups such as methoxy and ethoxy. Among them, from the viewpoint of YI in a high-temperature region, a methyl group is preferred.

Here, a and b are not limited as long as they are integers from 0 to 4. Among them, from the viewpoint of YI and residual stress, an integer of 0 to 2 is preferable, and from the viewpoint of YI in a high-temperature region, 0 is particularly preferable.

More specifically, when n is 0, 4-aminophenyl-4-aminobenzoate (APAB), 2-methyl-4-aminophenyl-4-amine Benzoate (ATAB), 4-aminophenyl-3-aminobenzoate (4,3-APAB), etc.

In the case where n is 1, [4-(4-aminobenzyl)oxyphenyl] 4-aminobenzoate and the like can be exemplified.

As the diamine used for the structural unit represented by the general formula (3) of this embodiment, the diamine represented by the following general formula (7) can be exemplified.

(In the formula, R ₄ and R ₅ independently represent a monovalent organic group having 1 to 20 carbon atoms. d and e are integers from 0 to 4)

Here, R ₄ and R ₅ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, and alkoxy groups such as methoxy and ethoxy groups. Among them, from the viewpoint of YI in a high-temperature region, a methyl group is preferred.

Here, c and d are not limited as long as they are integers from 0 to 4. Among them, from the viewpoint of YI and residual stress, an integer of 0 to 2 is preferable, and from the viewpoint of YI in a high-temperature region, 0 is particularly preferable.

More specifically, 4,4'-diamino diphenyl satin and 3,3'- diamino diphenyl satin can be exemplified.

As the diamine used for the structural unit represented by the general formula (4) of this embodiment, the diamine represented by the following general formula (8) can be exemplified.

Here, R ₆ and R ₇ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl; halogen-containing groups such as trifluoromethyl; and alkoxy groups such as methoxy and ethoxy. Among them, from the viewpoint of YI in a high-temperature region, a methyl group is preferred.

R ₈ and R ₉ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, or a halogen atom. Examples of the organic group include alkyl groups such as methyl, ethyl, and propyl; halogen-containing groups such as trifluoromethyl; alkoxy groups such as methoxy and ethoxy. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

f, g, h, and i are not limited as long as they are independently integers from 0 to 4. Among them, from the viewpoint of YI and residual stress, an integer of 0 to 2 is preferable, and from the viewpoint of YI in a high-temperature region, 0 is particularly preferable.

Z can be exemplified by single bonds, methylene, ethylidene, ether, ketone, and the like. Among them, from the viewpoint of YI in a high-temperature region, a single bond is more preferable.

More specifically, it can be exemplified by 9,9-bis(aminophenyl) stilbene, 9,9-bis(4-amino-3-methylphenyl) stilbene, 9,9-bis(4-amino -3-fluorophenyl) stilbene, 9,9-bis(4-hydroxy-3-aminophenyl) stilbene, 9,9-bis[4-(4-aminophenoxy)phenyl] stilbene, etc. It is preferable to use one or more selected from these.

As the diamine used for the structural unit represented by the general formula (5) of this embodiment, the diamine represented by the following general formula (9) can be exemplified.

Here, R ₁₀ and R ₁₁ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl; halogen-containing groups such as trifluoromethyl; and alkoxy groups such as methoxy and ethoxy. Among them, from the viewpoint of YI in a high-temperature region, a methyl group is preferred.

In addition, j and k are not limited as long as they are independently integers from 0 to 4. Among them, from the viewpoint of YI and residual stress, an integer of 0 to 2 is preferable, and from the viewpoint of YI in a high-temperature region, 0 is particularly preferable.

More specifically, 2,2'-bis(trifluoromethyl) benzidine and the like can be exemplified.

The polyimide film formed from the polyimide precursor of the first aspect of this embodiment has low residual stress, less warpage, less yellowness (YI value) in the high-temperature region, and higher elongation.

As a second aspect of the present embodiment, the following polyimide precursor can be provided: it is (a2) a polyimide precursor, which contains a structural unit represented by the following general formula (10):

Also, the weight average molecular weight is 30,000 or more and 300,000 or less.

{In the formula, X ₃ represents a tetravalent group derived from at least one selected from 4,4′-oxydiphthalic dianhydride (ODPA) and biphenyltetracarboxylic dianhydride (BPDA). R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1. And a, b and c are integers from 0 to 4}

Here, X ₃ is not limited as long as it is a tetravalent organic group derived from at least one selected from ODPA, BPDA, and TAHQ. From the viewpoint of CTE and Tg, BPDA and TAHQ are preferred.

Here, R ₁ to R ₃ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl, ethyl, and propyl, halogen-containing groups such as trifluoromethyl, and alkoxy groups such as methoxy and ethoxy groups. Among them, from the viewpoint of YI in a high-temperature region, a methyl group is preferred.

Here, a, b, c, and d are not limited as long as they are integers from 0 to 4. Among them, from the viewpoint of YI and residual stress, an integer of 0 to 2 is preferable, and from the viewpoint of YI in a high-temperature region, 0 is particularly preferable.

Here, n is 0 or 1. Among them, from the viewpoint of YI in the high-temperature region, it is preferably 0.

As the diamine used in the structure represented by the general formula (10), the diamine used in the general formula (6) can be used.

The polyimide precursor of the second aspect has a weight average molecular weight (Mw) of 30,000 to 300,000. If the weight average molecular weight is more than 30,000, the mechanical properties such as elongation and breaking strength are excellent, the residual stress is low, and the YI becomes low. If the weight average molecular weight is less than 300,000, it is easy to control the weight average molecular weight during the synthesis of polyamic acid, a resin composition with a moderate viscosity can be obtained, and the coating properties of the resin composition become good. Among them, the weight average molecular weight (Mw) is more preferably 35,000 or more and 250,000 or less, and particularly preferably 40,000 or more and 230,000 or less.

In the polyimide precursor of the second aspect of the present embodiment, the content of molecules with a molecular weight of less than 1,000 relative to the total amount of polyimide precursor is preferably less than 5% by mass, more preferably less than 1 quality the amount%. From the viewpoint that the residual stress of the polyimide film formed from the resin composition obtained by using such a polyimide precursor becomes low, and the haze of the inorganic film formed on the polyimide film becomes low Is better.

The content of molecules with a molecular weight of less than 1,000 relative to the total amount of polyimide precursor can be calculated from the peak area obtained by GPC measurement using a solution in which the polyimide precursor is dissolved.

The polyimide precursor of the second aspect of this embodiment has excellent storage stability and excellent coatability. In addition, the polyimide film formed from the polyimide precursor of the second aspect of the present embodiment has low residual stress, less warpage, less yellowness (YI value), higher elongation, and lower breaking strength. high.

In the polyimide precursors of the first aspect and the second aspect, it can be used in addition to the above general formulas (6) to (9) in a range that does not impair elongation, strength, stress and yellowness, etc. Diamines other than those indicated.

Examples of other diamines include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'- Diaminodiphenyl sulfide, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminodiphenyl Benzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diamine Diphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene , 1,3-bis(3-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl] benzene, 4,4-bis(4-aminophenoxy) Benzene, 4,4-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy) Phenyl] ether, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 9,10-bis(4-aminophenyl)anthracene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(4-(4-aminophenoxy)benzene Group) propane, 2,2-bis[4-(4-aminophenoxy)phenyl)hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, etc. Better make Use more than one of these.

The content of the above-mentioned other diamines in all diamines is preferably 20 mol% or less, particularly preferably 10 mol% or less.

[Manufacture of Polyimide Precursor]

The polyimide precursor (polyamide) of the present invention can be used for the above-mentioned general by using a tetracarboxylic dianhydride, a diamine (for example, APAB) used in the structural unit represented by the above general formula (1) The diamine (for example, 4,4'-DAS) of the structural unit represented by the formula (2) is synthesized by polycondensation reaction. The reaction is preferably carried out in a suitable solvent. Specifically, for example, a method of dissolving a specific amount of APAB and 4,4'-DAS in a solvent, adding a specific amount of tetracarboxylic dianhydride to the obtained diamine solution, and stirring.

In the diamine component, the molar ratio of the diamine used for the structural unit represented by the general formula (1) to the diamine used for the structural unit represented by the general formula (2) is only 99/1 to 1/99 Yes, there is no limit. Among the diamine components, if the diamine used in the structural unit represented by the general formula (2) is 1 mol% or more, there is a tendency for the yellowness to be good. If used in the structural unit represented by the general formula (1) When the diamine is 1 mol% or more, there is a tendency for the warpage after forming an inorganic film on the obtained polyimide film to be good. The molar ratio of the diamine used for the structural unit represented by the general formula (1) and the diamine used for the structural unit represented by the general formula (2) is preferably 95/5 to 50/50, more preferably 90/ 10~50/50. The molar ratio of the diamine used for the structural unit represented by the general formula (1) and the diamine used for the structural unit represented by the general formula (2) can also be 80/20~50/50, or 70 /30~50/50. It is preferable to set the molar ratio of the diamine used for the structural unit represented by the general formula (1) to the molar ratio of the diamine used for the structural unit represented by the general formula (2) or more.

In addition, the polyimide precursor of the second aspect of the present embodiment can be obtained by using a tetracarboxylic dianhydride (such as TAHQ) and a diamine (such as APAB) used in the structural unit represented by the above general formula (6) Polycondensation Synthesized by reaction. The reaction is preferably carried out in a suitable solvent. Specifically, for example, a method of adding a specific amount of TAHQ to the resulting diamine solution after dissolving a specific amount of APAB in a solvent, and stirring.

Regarding the ratio of the tetracarboxylic dianhydride component to the diamine component (mol ratio) when synthesizing the above polyimide precursor, the thermal linear expansion rate, residual stress, elongation and yellowness of the resulting resin film (hereinafter also From the viewpoint of controlling it within a desired range, it is preferably set to tetracarboxylic dianhydride: diamine = 100: 90 to 100: 110 (1 mole part relative to tetracarboxylic dianhydride, The range of diamine is 0.90~1.10 moles), more preferably it is set to the range of 100:95~100:105 (0.95~1.05 moles of diamine relative to 1 mole of acid dianhydride).

In this embodiment, when synthesizing polyamic acid which is a preferred precursor of polyimide, the molecular weight can be controlled by adjusting the ratio of the tetracarboxylic dianhydride component and the diamine component and adding an end-capping agent. The closer the ratio of the acid dianhydride component and the diamine component is to 1:1, and the smaller the amount of the blocking agent used, the greater the molecular weight of the polyamic acid.

As the tetracarboxylic dianhydride component and diamine component, high-purity products are recommended. The purity is preferably 98% by mass or more, more preferably 99% by mass or more, and still more preferably 99.5% by mass or more. When a plurality of acid dianhydride components or diamine components are used in combination, the acid dianhydride component or the diamine component as a whole may have the above purity, but it is preferably all types of acid dianhydride components and diamine components used Each has the above purity.

The solvent for the reaction is not particularly limited as long as it can dissolve the tetracarboxylic dianhydride component and the diamine component and the produced polyamic acid and can obtain a high molecular weight polymer. Specific examples of such solvents include aprotic solvents, phenol-based solvents, ethers, and alcohol-based solvents. As specific examples of such, as the aprotic solvent, for example, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl -2-pyrrolidone (NMP), N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea, the following general formula (13):

烷等。 Where R ₁₂ =Equamide M100 (trade name: manufactured by Idemitsu Kosei Co., Ltd.) represented by methyl and R ₁₂ =Equamide B100 (trade name: manufactured by Idemitsu Kosei Co., Ltd.) represented by n-butyl; etc.; Lactone-based solvents such as γ-butyrolactone and γ-valerolactone; phosphorus-containing amide-based solvents such as hexamethylphosphoramide and hexamethylphosphoric triamine; dimethyl sulfone and dimethyl sulfoxide , Sulfolane and other sulfur-containing solvents; ketone solvents such as cyclohexanone and methylcyclohexanone; tertiary amine solvents such as picoline and pyridine; acetic acid (2-methoxy-1-methylethyl ) Ester solvents such as esters; examples of the phenol solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2, 5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol and the like; examples of the ether and alcohol-based solvents include: 1,2-dimethoxy Ethyl ethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy) ethane, bis[2-(2-methoxyethoxy) ethyl ] Ether, tetrahydrofuran, 1,4-di

Alkane etc.

The boiling point of the solvent used in the synthesis of polyamic acid under normal pressure is preferably 60 to 300°C, more preferably 140 to 280°C, and particularly preferably 170 to 270°C. If the boiling point of the solvent is higher than 300°C, the drying step requires a long time. On the other hand, if the boiling point of the solvent is lower than 60 ℃, it is in the drying step In the case where the surface of the resin film is rough, bubbles and the like are mixed in the resin film, and a uniform film cannot be obtained.

In this way, from the viewpoints of solubility and edge shrinkage during coating, it is preferable to use a solvent having a boiling point of 170 to 270°C, more preferably a vapor pressure of 250 Pa or less at 20°C. More specifically, it is preferable to use at least one selected from the group consisting of N-methyl-2-pyrrolidone, γ-butyrolactone, and the compound represented by the above general formula (11).

The moisture content in the solvent is preferably 3000 mass ppm or less.

These solvents can be used alone or in combination of two or more.

In the (a) polyimide precursor of the present embodiment, the content of molecules with a molecular weight of less than 1,000 is preferably less than 5% by mass.

It is believed that the reason for the presence of molecules with molecular weights less than 1,000 in the (a) polyimide precursor is related to the water content of the solvent used in the synthesis. That is, it is considered that the reason for this is that a part of the acid anhydride groups of the acid dianhydride monomer is hydrolyzed into carboxyl groups by moisture, and it does not have a high molecular weight but remains in a low molecular state. Therefore, the water content of the solvent used in the polymerization reaction is preferably as small as possible. The water content of the solvent is preferably 3,000 mass ppm or less, and more preferably 1,000 mass ppm or less.

It is believed that the water content of the solvent is related to the following factors: the grade of the solvent used (dehydration grade, general grade, etc.), the solvent container (bottle, 18L tank, drum, etc.), the storage state of the solvent (the presence or absence of the sealing of rare gas, etc.) ), the time from opening to use (use immediately after opening, or use over time after opening, etc.), etc. It is also considered to be related to the replacement of rare gas in the reactor before synthesis and the presence or absence of the circulation of rare gas during synthesis. Therefore, it is recommended to use high-purity products as raw materials in the synthesis of (a) polyimide precursors, use solvents with low water content, and take measures before and during the reaction so that moisture from the environment is not mixed into Within the system.

When each monomer component is dissolved in a solvent, it can be heated as necessary.

(a) The reaction temperature during synthesis of the polyimide precursor is preferably set at 0°C to 120°C, more preferably at 40°C to 100°C, and even more preferably at 60 to 100°C. By conducting the polymerization reaction at this temperature, a polyimide precursor with a relatively high degree of polymerization can be obtained. The polymerization time is preferably 1 to 100 hours, and more preferably 2 to 10 hours. By setting the polymerization time to 1 hour or more, a polyimide precursor with a uniform degree of polymerization can be obtained, and by setting it to 100 hours or less, a polyimide precursor with a high degree of polymerization can be obtained.

In a preferred aspect of this embodiment, (a1) the polyimide precursor and (a2) the polyimide precursor have the following characteristics.

After the solution obtained by dissolving the (a) polyimide precursor in a solvent (for example, N-methyl-2-pyrrolidone) is coated on the surface of the support, the solution is placed under a nitrogen atmosphere ( For example, in a nitrogen gas with an oxygen concentration of 2,000 ppm or less), the resin obtained by heating (for example, 1 hour) at 300 to 550°C (for example, 430°C) to imidate the polyimide precursor, a 10 μm film Thick yellowness is below 30.

After the solution obtained by dissolving the (a) polyimide precursor in a solvent (for example, N-methyl-2-pyrrolidone) is coated on the surface of the support, the solution is placed under a nitrogen atmosphere ( For example, in a nitrogen gas with an oxygen concentration of 2,000 ppm or less), the resin obtained by heating (for example, 1 hour) at 300 to 550°C (for example, 430°C) to imidate the polyimide precursor has residual stress. 25MPa or less.

The polyimide precursor of the present embodiment can, if necessary, contain a polyimide precursor having a structure represented by the following general formula (14) within a range that does not impair the desired performance of the present invention: [化26]

{In the general formula (14), there are a plurality of R ₁₃ which are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon having a carbon number of 1 to 20 or a monovalent aromatic group, and X ₄ is a carbon number of 4 to 32 Valence organic group, Y is a divalent organic group with a carbon number of 4~32. Among them, the structural units corresponding to the above general formula (1) and the above general formula (6) are excluded}.

In the general formula (14), R _{13 is} preferably a hydrogen atom. In addition, X _{3 is} preferably a tetravalent aromatic group from the viewpoints of heat resistance, reduction in YI value, and total light transmittance. In addition, from the viewpoints of heat resistance, reduction in YI value, and total light transmittance, Y is preferably a divalent aromatic group or an alicyclic group.

The mass ratio of the polyimide precursor containing the structural unit represented by the general formula (14) in the (a) polyimide precursor of this embodiment, relative to the (a) polyimide precursor All, preferably 80% by mass or less, from the viewpoint of the decrease in the oxygen dependency of the YI value and the total light transmittance, it is more preferably 70% by mass or less.

In a preferred aspect of this embodiment, (a1) a polyimide precursor and (a2) a portion of the polyimide precursor system may be imidized. In this case, the imidate ratio is preferably 80% or less, and more preferably 50% or less. This partial imidization can be obtained by heating the above (a) polyimide precursor to dehydrate and close the ring. The heating may be performed at a temperature of preferably 120 to 200°C, more preferably 150 to 180°C, preferably 15 minutes to 20 hours, more preferably 30 minutes to 10 hours.

In addition, N,N-dimethylformamide dimethyl acetal or N,N-dimethylformamide diethyl acetal is added to the polyamic acid obtained by the above reaction and heated, After part or all of a carboxylic acid is esterified, it can be used as the (a) polyimide precursor of the present embodiment, whereby the room temperature guarantee can also be obtained Resin composition with improved viscosity stability at the time of tube. These ester-modified polyamic acids can be additionally obtained by making the above-mentioned acid dianhydride component equivalent to 1 equivalent of a monohydric alcohol and thionyl chloride and dicyclohexylcarbodiacid with respect to the acid anhydride group After dehydrating condensation agents such as amines are sequentially reacted, condensation reactions with diamine components are performed.

From the viewpoint of coating film formability, the ratio of (a) polyimide precursor (preferably polyamic acid) in the resin composition of this embodiment is preferably 3 to 50% by mass, more preferably It is 5-40% by mass, particularly preferably 10-30% by mass.

<resin composition>

Another aspect of the present invention provides a resin composition containing the above (a) polyimide precursor and (b) organic solvent. The resin composition is typically a varnish.

[(b) Organic solvent]

(B) The organic solvent of this embodiment is not particularly limited as long as it can dissolve the (a) polyimide precursor and other components used arbitrarily. As such (b) organic solvent, the solvent described in the foregoing can be used as a solvent that can be used in the synthesis of (a) a polyimide precursor. The preferred organic solvents are also the same as described above. The (b) organic solvent in the resin composition of this embodiment may be the same as or different from the solvent used in the synthesis of (a) polyimide precursor.

(b) The organic solvent is preferably an amount such that the solid content concentration of the resin composition becomes 3 to 50% by mass. In addition, it is preferable to adjust (b) the composition and amount of the organic solvent so that the viscosity (25° C.) of the resin composition becomes 500 mPa‧s to 100,000 mPa‧s, and then add it.

[Other ingredients]

The resin composition of this embodiment may contain (c) a surfactant, (d) an alkoxysilane compound, etc. in addition to the components (a) and (b) above.

The resin composition of this embodiment includes a precursor selected from (a) polyimide precursor, (b) organic solvent At least one of the group consisting of an agent, (c) a surfactant, and (d) an alkoxysilane compound.

The skeleton of the polyimide precursor is not limited to the skeleton described in the first aspect and the second aspect above. That is, the skeleton of the polyimide precursor is not particularly limited as long as it is a skeleton represented by the following general formula (1).

{In the formula, X ₁ represents a tetravalent base with a carbon number of 4 to 32. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1. And a, b and c are integers from 0 to 4}

((c) surfactant)

The resin composition of this embodiment can improve the coatability of the resin composition by adding a surfactant. Specifically, the occurrence of streaks in the coating film can be prevented.

Examples of such surfactants include polysiloxane-based surfactants, fluorine-based surfactants, and nonionic surfactants other than these. As an example of such, Examples of polysiloxane-based surfactants include organic silicone polymers (Organosilicone polymer) KF-640, 642, 643, KP341, X-70-092, and X-70-093 (the above are trade names, Shin-Etsu Chemical Co., Ltd.), SH-28PA, SH-190, SH-193, SZ-6032, SF-8428, DC-57, DC-190 (the above are trade names, manufactured by Toray Dow Corning Silicone Company), SILWET L-77, L-7001, FZ-2105, FZ-2120, FZ-2154, FZ-2164, FZ-2166, L-7604 (the above are trade names, manufactured by Nippon Unicar), DBE-814, DBE-224, DBE-621, CMS-626, CMS-222, KF-352A, KF-354L, KF-355A, KF-6020, DBE-821, DBE-712 (Gelest), BYK-307 , BYK-310, BYK-378, BYK-333 (the above are trade names, manufactured by BYK-Chemie Japan), Glanol (trade names, manufactured by Kyoeisha Chemical Company), etc.; Examples of fluorine-based surfactants include MEGAFAC F171, F173, and R-08 (manufactured by Dainippon Ink Chemical Industry Co., Ltd., trade name), Fluorad FC4430, FC4432 (Sumitomo 3M Co., Ltd., trade name), etc.; Examples of non-ionic surfactants other than these include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether, and the like.

Among these surfactants, polysiloxane-based surfactants and fluorine-based surfactants are preferred from the viewpoint of the coating properties (stripe suppression) of the resin composition, and the oxygen concentration in the curing step From the viewpoint of the influence of the value and the total light transmittance, the silicone surfactant is preferred.

When the (c) surfactant is used, the amount of the compound is preferably 0.001 to 5 parts by mass, more preferably 0.01 to 3 parts relative to 100 parts by mass of the (a) polyimide precursor in the resin composition. Quality parts.

(d) Alkoxysilane compounds

In order for the resin film obtained from the resin composition of the present embodiment to exhibit sufficient adhesion to the support during the manufacturing process of a flexible device, etc., the resin composition can be used with respect to (a) a polyimide precursor 100% by mass and containing 0.01 to 20% by mass of alkoxysilane compound. By setting the content of the alkoxysilane compound to 100% by mass of the polyimide precursor to 0.01% by mass or more, good adhesion to the support can be obtained. In addition, from the viewpoint of storage stability of the resin composition, the content of the alkoxysilane compound is preferably 20% by mass or less. The content of the alkoxysilane compound with respect to 100 parts by mass of the polyimide precursor is more preferably 0.02 to 15% by mass, further preferably 0.05 to 10% by mass, and particularly preferably 0.1 to 8% by mass.

By using an alkoxysilane compound as an additive of the resin composition of this embodiment, in addition to improving the above-mentioned adhesion, the coating property of the resin composition can be improved (striated unevenness is suppressed), and the resulting cured film can be reduced Dependency of oxygen concentration during curing of YI value.

Examples of the alkoxysilane compound include 3-ureidopropyltriethoxysilane, bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-glycidoxy Propyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltripropoxysilane, γ-aminopropyltributoxysilane, γ-aminoethyltriethyl Oxysilane, γ-aminoethyltripropoxysilane, γ-aminoethyltributoxysilane, γ-aminobutyltriethoxysilane, γ-aminobutyltrimethoxysilane , Γ-aminobutyltripropoxysilane, γ-aminobutyltributoxysilane, phenylsilanetriol, trimethoxyphenylsilane, trimethoxy(p-tolyl)silane, diphenyl Silanediol, dimethoxydiphenylsilane, diethoxydiphenylsilane, dimethoxydi-p-tolylsilane, triphenylsilanol, and alkoxysilane represented by the following structures, respectively It is preferable to use one or more compounds selected from these compounds for compounds and the like.

The method for producing the resin composition of this embodiment is not particularly limited. For example, the following method can be used.

In the case where the solvent used when synthesizing the (a) polyimide precursor is the same as the (b) organic solvent, the synthetic polyimide precursor solution can be used directly as the resin composition. In addition, if necessary, more than one (b) organic solvent and other components can be added to the polyimide precursor in the temperature range of room temperature (25°C) to 80°C, and used as a resin composition after stirring and mixing . For the stirring and mixing, a suitable device such as a Sany motor (manufactured by Xindong Chemical Co., Ltd.) equipped with a stirring wing, an orbiting revolution mixer, or the like can be used. Furthermore, heat of 40 to 100°C can be applied as needed.

On the other hand, when the solvent used in the synthesis of (a) polyimide precursor is different from (b) organic solvent, the synthesized polymer can be removed by suitable methods such as reprecipitation and solvent distillation. After removing the solvent in the imidate precursor solution to separate (a) the polyimide precursor, add (b) an organic solvent and other components as needed within the temperature range of room temperature to 80 ℃, and stir and mix , Thereby preparing a resin composition.

After the resin composition is prepared in the above manner, the composition solution is heated at, for example, 130 to 200°C for, for example, 5 minutes to 2 hours, thereby partially dehydrating a part of the polyimide precursor without causing polymer precipitation. Amidation. Here, by controlling the heating temperature and the heating time, it is possible to control the rate of amidation. By partially imidizing the polyimide precursor, the viscosity stability of the resin composition when stored at room temperature can be improved. From the viewpoint of achieving a balance between the solubility of the polyimide precursor in the resin composition solution and the storage stability of the solution as the range of the imidate ratio, it is preferably 5% to 70%.

The resin composition of this embodiment preferably has a water content of 3,000 mass ppm or less.

From the viewpoint of viscosity stability when storing the resin composition, the moisture content of the resin composition is more preferably 1,000 mass ppm or less, and further preferably 500 mass ppm or less.

The solution viscosity of the resin composition of this embodiment is preferably 500 to 200,000 mPa‧s at 25°C, more preferably 2,000 to 100,000 mPa‧s, and particularly preferably 3,000 to 30,000 mPa‧s. The viscosity of this solution can be measured using an E-type viscometer (manufactured by Toki Industries Co., Ltd., VISCONICEHD). If the viscosity of the solution is less than 300 mPa‧s, the coating will be difficult when the film is formed, and if it is higher than 200,000 mPa‧s, there may be a problem that the stirring during synthesis becomes difficult.

When synthesizing (a) a polyimide precursor, even if the solution becomes high in viscosity, a resin composition with a viscosity with better handleability can be obtained by adding a solvent after the reaction and stirring.

In a preferred aspect, the resin composition of this embodiment has the following characteristics.

After coating the resin composition on the surface of the support to form a coating film, the coating film is heated at 300° C. to 550° C. under a nitrogen atmosphere (for example, nitrogen gas with an oxygen concentration of 2,000 ppm or less), thereby allowing The resin film obtained by imidization of the polyimide precursor contained in the above coating film has a yellowness YI of 10 μm and a film thickness of 30 or less.

After coating the resin composition on the surface of the support to form a coating film, the coating film is heated at 300° C. to 550° C. under a nitrogen atmosphere (for example, nitrogen gas with an oxygen concentration of 2,000 ppm or less), thereby allowing The residual stress of the resin film system obtained by acylation of the polyimide precursor contained in the coating film is 25 MPa or less.

The resin composition of this embodiment can be preferably used to form a transparent substrate of a display device such as a liquid crystal display, an organic electroluminescence display, a field emission display, and electronic paper, for example. Specifically, it can be used for forming a thin film transistor (TFT) substrate, a color filter substrate, a transparent conductive film (ITO, Indium Thin Oxide) substrate, etc.

The resin precursor of the present embodiment can form a polyimide film having a residual stress of 25 MPa or less, so it is easy to apply to a display having a TFT element device on a colorless transparent polyimide substrate Display manufacturing steps.

<resin film>

Another aspect of the present invention provides a resin film formed from the above resin precursor.

Furthermore, still another aspect of the present invention provides a method of manufacturing a resin film from the above resin composition.

The resin film of the present embodiment is characterized by comprising: a step of forming a coating film by coating the resin composition on the surface of the support (coating step); by heating the support and the coating film A step (heating step) of forming a polyimide resin film with a polyimide precursor contained in the coating film (imidization); and a step (peeling) of the polyimide resin film from the support step).

Here, the support is not particularly limited as long as it has heat resistance to the heating temperature of the subsequent step and good peelability. For example, glass (eg, alkali-free glass) substrates; silicon wafers; PET (polyethylene terephthalate), OPP (extended polypropylene), polyethylene glycol terephthalate, polyethylene Naphthalene dicarboxylate, polycarbonate, polyimide, polyimide amide imide, polyether amide imide, polyether ether ketone, polyether sulfone, polyphenylene sulfide, polyphenylene sulfide and other resins Substrate; metal substrates such as stainless steel, alumina, copper, nickel, etc.

In the case of forming a film-shaped polyimide molded body, for example, a glass substrate, a silicon wafer, etc. is preferable. In the case of forming a film-shaped or sheet-shaped polyimide molded body, for example, it is preferable to include PET (polyethylene terephthalate), OPP (extended polypropylene) and other supports.

As the coating method, for example, coating by a blade coater, an air knife coater, a roll coater, a spin coater, a flow coater, a die coater, a bar coater, etc. can be applied Method, spin coating, spray Coating methods such as fog coating and dip coating; printing technologies represented by screen printing and gravure printing.

The coating thickness should be appropriately adjusted according to the desired thickness of the resin film and the content of the polyimide precursor in the resin composition, preferably about 1 to 1,000 μm. The coating step may be performed at room temperature, but if the viscosity is to be reduced and the workability is improved, the resin composition may be heated at a temperature in the range of 40 to 80°C.

After the coating step, a drying step may be performed, or the drying step may be omitted and the subsequent heating step may be directly performed. This drying step is performed for the purpose of removing the organic solvent. In the case of performing the drying step, for example, a suitable device such as a heating plate, a box dryer, a conveyor dryer, etc. can be used. The drying step is preferably performed at 80 to 200°C, and more preferably performed at 100 to 150°C. The execution time of the drying step is preferably set to 1 minute to 10 hours, and more preferably set to 3 minutes to 1 hour.

A coating film containing a polyimide precursor is formed on the support in the above-mentioned manner.

Then, a heating step is performed. The heating step is a step of removing the organic solvent remaining in the coating film in the above-mentioned drying step, and performing the amide imidization reaction of the polyimide precursor in the coating film to obtain a film containing polyimide.

This heating step can be performed, for example, using an inert gas oven, a heating plate, a box-type dryer, a conveyor-type dryer, or the like. This step can be performed simultaneously with the above-mentioned drying step, or two steps can be performed one after another.

The heating step can be performed in an air environment, but from the viewpoint of safety and the transparency and YI value of the resulting polyimide film, it is recommended to be performed in an inert gas environment. Examples of the inert gas include nitrogen and argon.

The heating temperature can be appropriately set according to the type of (b) organic solvent, preferably 250°C to 550°C, more preferably 300 to 450°C. If it is above 250°C, the imidate will be sufficient. If it is 550°C, Under the circumstances, no disadvantages such as a decrease in transparency and deterioration of heat resistance of the resulting polyimide film will occur. The heating time is preferably about 0.5 to 3 hours.

In this embodiment, the oxygen concentration of the surrounding environment in the heating step is preferably 2,000 mass ppm or less, and more preferably 100 mass ppm or less from the viewpoint of the transparency and YI value of the obtained polyimide film. Furthermore, it is preferably 10 mass ppm or less. By heating in an environment with an oxygen concentration of 2,000 mass ppm or less, the YI value of the resulting polyimide film can be 30 or less.

Depending on the use purpose and purpose of the polyimide resin film, a peeling step of peeling the resin film from the support may be required after the above heating step. This peeling step is preferably performed after cooling the resin film on the support to about room temperature to about 50°C.

Examples of the peeling step include the following aspects (1) to (4).

(1) After the structure including the polyimide resin film/support is prepared by the above method, the laser is irradiated from the support side of the structure to erode the interface between the support and the polyimide resin film Processing method to peel off the polyimide resin. Examples of the types of lasers include solid (YAG (Yttrium Aluminum Garnet) lasers and gas (UV (ultraviolet) excimer) lasers. Preferably, a spectrum with a wavelength of 308 nm or the like is used (refer to Japanese Patent Publication 2007-512568, Japanese Patent Publication 2012-511173, etc.).

(2) Before coating the resin composition on the support, a peeling layer is formed on the support, and then a structure including a polyimide resin film/peeling layer/support is obtained, and the polyimide resin film is peeled off. method. Examples of the peeling layer include a method of using Parylene (registered trademark, manufactured by Japan Parylene Contract Co., Ltd.) and tungsten oxide; a method of using a release agent such as vegetable oil, polysiloxane, fluorine, and alkyd. (Refer to Japanese Patent Laid-Open No. 2010-67957, Japanese Patent Laid-Open No. 2013-179306, etc.).

This method (2) can also be used in combination with the laser irradiation of (1) above.

(3) A method of obtaining a polyimide resin film by using an etchable metal substrate as a support, obtaining a structure including a polyimide resin film/support, and etching the metal with an etchant. As the metal, for example, copper (specific examples are electrolytic copper foil "DFF" manufactured by Mitsui Metal Mining Co., Ltd.), aluminum, and the like. As an etchant, iron chloride or the like is used for copper, and dilute hydrochloric acid or the like is used for aluminum.

(4) After obtaining the structure including the polyimide resin film/support by the above method, an adhesive film is attached to the surface of the polyimide resin film to separate the adhesive film/polyimide resin film from the support , And then separate the polyimide resin film from the adhesive film.

Among these peeling methods, from the viewpoint of the refractive index difference, YI value, and elongation of the front and back sides of the resulting polyimide resin film, the method (1) or (2) is suitable for the resulting polyimide From the viewpoint of the difference in refractive index between the front and back of the imine resin film, the method (1) is more suitable.

In addition, in the method (3), when copper is used as the support, the YI value of the resulting polyimide resin film tends to increase, and the elongation tends to decrease. It is believed to be due to the influence of copper ions.

The thickness of the resin film obtained by the above method is not particularly limited, but is preferably in the range of 1 to 200 μm, and more preferably 5 to 100 μm.

The resin film of this embodiment can have a yellowness YI of 10 μm or less in thickness of 30 or less. In addition, the residual stress may be 25 MPa or less. In particular, the yellowness YI of a film thickness of 10 μm can be 30 or less and the residual stress can be 25 MPa or less. Such characteristics can be achieved, for example, by subjecting the resin precursor of the present invention to a nitrogen atmosphere (for example, nitrogen with an oxygen concentration of 2,000 ppm or less), preferably at 300°C to 550°C, and more preferably at 350°C to 450°C. The imidization is achieved well.

The resin film of this embodiment can further have a tensile elongation of 15% or more. The tensile elongation of the resin film may further be 20% or more, especially 30% or more. This tensile elongation can be measured using a commercially available tensile tester using a resin film with a thickness of 10 μm as a sample.

The resin film of the present embodiment is a film containing polyimide obtained by thermally imidizing (a1) a polyimide precursor contained in the resin composition. Therefore, it contains the structural unit represented by the following general formula (11):

{In the formula, X ₁ and X ₂ represent a tetravalent base with a carbon number of 4 to 32. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1. And a, b and c are integers from 0 to 4. Y is at least one selected from the group consisting of the aforementioned general formulas (3), (4) and (5). l and m independently represent integers above 1 and satisfy 0.01≦l/(l+m)≦0.99}.

The lower limit of l/(l+m) can be 0.05, 0.10, 0.20, 0.30, or 0.40.

The upper limit of l/(l+m) can be 0.95, 0.90, 0.80, 0.70, or 0.60.

As described above, it is preferable that the residual stress is 25 MPa or less, the YI is 30 or less, the glass transition temperature is 400° C. or more, the elongation is 15% or more, and the breaking strength is 250 MPa or more.

In addition, as a second aspect, it is a film containing (a2) the polyimide precursor contained in the resin composition by thermal imidization of polyimide. Therefore, it contains the structural unit represented by the following general formula (12): [Chem 30]

{In the formula, X ₃ represents a tetravalent group derived from at least one selected from 4,4′-oxydiphthalic dianhydride (ODPA) and biphenyltetracarboxylic dianhydride (BPDA). R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1. And a, b, and c are integers from 0 to 4} and a resin film with an elongation of 15% or more, preferably a residual stress of 25 MPa or less, a YI of 30 or less, a glass transition temperature of 400° C or more, and a breaking strength of 250MPa or more.

<Laminate>

Another aspect of the present invention provides a laminate including a support and a polyimide resin film formed from the resin composition on the surface of the support.

Yet another aspect of the present invention provides a method for manufacturing the above laminate.

The layered body of this embodiment can be obtained by a method of manufacturing a layered body including the steps of: forming a coating film by coating the above resin composition on the surface of a support (coating step); and by applying The step of heating the support and the coating film to imide the polyimide precursor contained in the coating film to form a polyimide resin film (heating step).

The manufacturing method of the above-mentioned laminate can be implemented in the same manner as the manufacturing method of the above-mentioned resin film, for example, except that the peeling step is not performed.

The laminate can be preferably used for the manufacture of flexible devices, for example.

If further detailed, it is as follows.

In the case of forming a flexible display, a glass substrate is used as a support, a flexible substrate is formed thereon, and a TFT and the like are formed thereon. The steps of forming TFTs and the like on a flexible substrate are typically performed at a temperature in a wide range of 150 to 650°C. However, in order to achieve the desired performance in reality, it is necessary to form TFT-IGZO (InGaZnO) oxide semiconductor or TFT (a-Si-TFT, poly-Si- TFT).

On the other hand, due to such thermal history, various physical properties (especially yellowness or elongation) of the polyimide film tend to decrease. If the temperature exceeds 400°C, especially the yellowness or elongation decreases. However, the polyimide film obtained from the polyimide precursor of the present invention has little decrease in yellowness or elongation even in a high-temperature region of 400° C. or higher, and can be used well in this region.

Furthermore, in this embodiment, a laminate including a polyimide film layer and an LTPS (low temperature polysilicon TFT) layer can be provided, the polyimide film layer containing a polyimide represented by the following general formula (13) Imine.

{In the formula, X ₁ represents a tetravalent base with a carbon number of 4 to 32. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1. And a, b and c are integers from 0 to 4}

As a method of manufacturing the laminate, after manufacturing the laminate including the above-mentioned support and a polyimide resin film formed of the above-mentioned resin composition on the surface of the support, an amorphous Si layer is formed at 400~ After dehydrogenation annealing at 450°C for about 0.5 to 3 hours, the LTPS layer can be formed by crystallization by an excimer laser or the like. After that, the glass and the polyamide are separated by laser peeling, etc. The amine film is peeled off, whereby the above laminate can be obtained.

The laminate system including the polyimide film layer containing the polyimide represented by the general formula (13) and the LTPS (low temperature polysilicon TFT) layer has less peeling or bulging after the thermal cycle test and less warpage of the substrate.

In addition, if the residual stress generated in the flexible substrate and the polyimide resin film is high, the laminate including the two may expand in the high-temperature TFT step and shrink when cooled at room temperature, which may cause warpage of the glass substrate And problems such as breakage and peeling of the flexible substrate from the glass substrate. Generally, the thermal expansion coefficient of the glass substrate is smaller than that of resin, so residual stress is generated between the glass substrate and the flexible substrate. As described above, the resin film of the present embodiment can set the residual stress generated between the glass substrate and the glass substrate to 25 MPa or less, so it can be preferably used for the formation of flexible displays.

Furthermore, in the polyimide film system of the present embodiment, the yellowness YI of a film thickness of 10 μm can be 30 or less, and the tensile elongation can be 15% or more. As a result, the resin film of the present embodiment is excellent in breaking strength when processing a flexible substrate, so that the yield when manufacturing a flexible display can be improved.

Also, as another aspect, it is possible to provide a film with a film thickness of 10 μm and a yellowness of 20 or less after heating at 400° C. or more, an absorbance of 308 nm at a film thickness of 0.1 μm of 0.6 or more and 2.0 or less, and an elongation of 15 % Polyimide film.

By setting YI to 20 or less, a flexible substrate can be produced without reducing the image quality when the display is made.

It is more preferably 18 or less, and particularly preferably 16 or less.

When the absorbance at 308 nm at a film thickness of 0.1 μm is 0.6 or more and 2.0 or less and the elongation is 15% or more, for example, the polyimide film can be easily peeled from the glass substrate by laser. From the viewpoint of suppressing dust after laser peeling, it is preferably 0.6 or more and 1.5 or less and the elongation is 20% or more, for example, from the viewpoint of not degrading the performance of the organic EL element, it is particularly preferably 0.6 or more and 1.0 Below and the elongation is 20% or more.

The upper limit of the elongation is not particularly limited, and may be 80% or less, 70% or less, 60% or less, 50% or less, or 40% or less.

In addition, when the laser is peeled off, the polyimide film may burn due to laser light, and the burning residue is dust.

Therefore, another aspect of the present invention provides a display substrate.

Furthermore, still another aspect of the present invention provides a method of manufacturing the above display substrate.

The manufacturing method of the display substrate of the present embodiment is characterized by including the steps of: forming a coating film by coating the resin composition on the surface of the support (coating step); by applying the support and the coating The step of heating the film to imidate the polyimide precursor contained in the coating film to form a polyimide resin film (heating step); forming an element or a circuit on the polyimide resin film Step (element, circuit formation step); and the step of peeling the polyimide resin film on which the element or circuit is formed from the support (peeling step).

In the above method, the coating step, the heating step, and the peeling step can be performed in the same manner as the above-described resin film manufacturing method.

The component and circuit formation steps can be implemented by methods known to the industry.

The resin film of this embodiment that satisfies the above physical properties can be preferably used for applications that are restricted in use due to the yellow color of the existing polyimide film, especially for colorless transparent substrates for flexible displays and color filters Protective film and other uses. Furthermore, it can also be used for light-scattering sheets and coating films such as protective films, TFT-LCD, etc. (such as TFT-LCD interlayers, gate insulating films, liquid crystal alignment films, etc.), ITO substrates for touch panels, and smartphones Use it instead of the glass-covered resin substrate In the field of colorless transparency and low birefringence. If the polyimide of this embodiment is used as a liquid crystal alignment film, a TFT-LCD with a high aperture ratio and a high contrast ratio can be manufactured.

The resin film and the laminated body manufactured using the polyimide precursor and the resin precursor of the present embodiment can be used not only as a semiconductor insulating film, a TFT-LCD insulating film, an electrode protective film, etc. but also in flexible devices It is especially used as a substrate in manufacturing. Here, as a flexible device to which the resin film and the laminate of the present embodiment can be applied, for example, a flexible display, a flexible solar battery, a flexible touch panel electrode substrate, a flexible lighting, a flexible battery, etc. may be mentioned.

[Example]

Hereinafter, the present invention will be described in more detail based on examples, but these are described for explanation, and the scope of the present invention is not limited by the following examples.

Various evaluations of Examples and Comparative Examples were carried out as follows.

<Measurement of weight average molecular weight>

The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) under the following conditions.

As a solvent, N,N-dimethylformamide (manufactured by Wako Pure Chemical Industries, Ltd., for high-performance liquid chromatography, and 24.8 mmol/L of lithium bromide monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.) were added immediately before the measurement , Purity 99.5%) and 63.2mmol/L phosphoric acid (made by Wako Pure Chemical Industries, for high performance liquid chromatography) and dissolved). The calibration curve used to calculate the weight average molecular weight was prepared using standard polystyrene (manufactured by Tosoh Corporation).

Column: Shodex KD-806M (manufactured by Showa Denko)

Flow rate: 1.0mL/min

Column temperature: 40℃

Pump: PU-2080Plus (made by JASCO)

Detector: RI-2031Plus (RI: differential refractometer, manufactured by JASCO) and UV-2075Plus (UV-VIS: ultraviolet-visible absorbance meter, manufactured by JASCO)

<Evaluation of the content of molecules with a molecular weight of less than 1,000 (low molecular weight content)>

The content of molecules with a molecular weight of less than 1,000 in the resin is calculated as the ratio (percentage) of the peak area occupied by the component with a molecular weight of less than 1,000 to the peak area of the entire molecular weight distribution using the GPC measurement results obtained above .

<Evaluation of Moisture>

The water content of the synthetic solvent and the resin composition (varnish) was measured using a Karl Fischer moisture measuring device (a trace moisture measuring device AQ-300, manufactured by Hiranuma Industries).

<Evaluation of viscosity stability of resin composition>

For the resin compositions prepared in the examples and comparative examples, the sample that was allowed to stand at room temperature for 3 days after preparation was used as the prepared sample, and the viscosity was measured at 23°C; after that, it was further allowed to stand at room temperature Set a sample of 2 weeks as a sample after 2 weeks, and perform the viscosity measurement at 23°C again. These viscosity measurements were carried out using a viscometer with a thermostat (TV-22 manufactured by Toki Industry Machinery Co., Ltd.).

Using the above measured values, the rate of change in viscosity at room temperature for 2 weeks was calculated by the following formula.

Rate of viscosity change at room temperature for 2 weeks (%) = [(viscosity of sample after 2 weeks)-(viscosity of sample after preparation)]/(viscosity of sample after preparation) × 100

The rate of change in viscosity at room temperature for 2 weeks was evaluated according to the following criteria.

◎: Viscosity change rate is below 5% (storage stability is "excellent")

○: Viscosity change rate exceeds 5 and is 10% or less (storage stability "good")

×: Viscosity change rate exceeds 10% (storage stability is "bad")

<Evaluation of varnish coatability>

Using a bar coater, the resin compositions prepared in the examples and comparative examples were applied to an alkali-free glass substrate (size 37×47 mm, thickness 0.7 mm) so that the film thickness after curing became 15 μm. Pre-bake at 60°C for 60 minutes.

Using a surface profilometer (manufactured by Tencor Corporation, model name P-15), the step difference of the coating film surface was measured to evaluate the coatability of the varnish.

◎: The step difference of the surface is 0.1 μm or less (coatability "excellent")

○: The step difference of the surface exceeds 0.1 and is 0.5 μm or less (coatability “good”)

×: The step difference of the surface exceeds 0.5 μm (coating property “poor”)

<Evaluation of Residual Stress>

Each resin composition was coated on a 6-inch silicon wafer with a thickness of 625 μm ± 25 μm whose "warpage amount" was previously measured by a spin coater, and prebaked at 100°C for 7 minutes. Thereafter, a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B) was used to adjust the oxygen concentration in the storage to 10 mass ppm or less, and heat curing treatment was performed at 430°C for 1 hour (curing Processing) to produce a silicon wafer with a cured polyimide resin film with a thickness of 10 μm.

A residual stress measuring device (manufactured by Tencor, model name FLX-2320) was used to measure the amount of warpage of the wafer, and the residual stress generated between the silicon wafer and the resin film was evaluated.

◎: Residual stress exceeds -5 and is 15 MPa or less (evaluation of residual stress is "excellent")

○: Residual stress exceeds 15 and is 25 MPa or less (evaluation of residual stress is "good")

×: Residual stress exceeds 25 MPa (evaluation of residual stress "bad")

<Warpage evaluation of polyimide resin film formed with inorganic film>

The resin compositions prepared in the examples and the comparative examples were spin-coated on a 6-inch silicon wafer substrate provided with an aluminum vapor deposition layer on the surface so that the film thickness after curing became 10 μm. Bake for 7 minutes. Thereafter, a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B) was used to adjust the oxygen concentration in the storage to 10 mass ppm or less, and heat curing treatment was performed at 430°C for 1 hour to produce A wafer formed with a polyimide resin film. Using this wafer, a silicon nitride (SiNx) film as an inorganic film was formed on the polyimide resin film by CVD (chemical vapor deposition) method at 350°C with a thickness of 100 nm to obtain a formation Laminated wafer with inorganic film/polyimide resin.

The laminate wafer obtained above is immersed in a dilute hydrochloric acid aqueous solution, and the two layers of the inorganic film and the polyimide film are integrally peeled from the wafer, thereby obtaining a polyimide film having an inorganic film formed on the surface Samples. Using this sample, the warpage of the polyimide resin film was evaluated.

◎: No warping (warping "excellent")

○: Only a small amount of warping (warping "good")

×: The film curled due to warpage (warpage "bad")

<Evaluation of yellowness (YI value)>

Wafers (those with no inorganic film formed) were produced in the same manner as in the above <Warpage Evaluation of Polyimide Resin Film with Inorganic Film Formed>. The wafer was immersed in a dilute hydrochloric acid aqueous solution to peel off the polyimide resin film, thereby obtaining a resin film.

The obtained polyimide resin film was measured by Nippon Denshoku Industries Co., Ltd. (Spectrophotometer: SE600) using a D65 light source (YI value converted to a film thickness of 10 μm).

<Evaluation of Elongation and Breaking Strength>

Wafers (those with no inorganic film formed) were produced in the same manner as in the above <Warpage Evaluation of Polyimide Resin Film with Inorganic Film Formed>. Using a wafer dicing machine (DAD3350 manufactured by DISCO Co., Ltd.), a 3 mm wide cut was cut into the polyimide resin film of the wafer, immersed in a dilute hydrochloric acid aqueous solution overnight, and the resin film was peeled off and dried . Cut it to a length of 50mm, As a sample.

For the above samples, TENSILON (UTM-II-20 manufactured by Orientec) was used, and the elongation and breaking strength were measured at a test speed of 40 mm/min and an initial weight of 0.5 fs.

<Measurement of absorbance at 308 nm of polyimide resin film>

The above varnish was spin-coated on a quartz glass substrate, respectively, and heated at 430° C. for 1 hour in a nitrogen atmosphere, thereby obtaining a polyimide resin film with a film thickness of 0.1 μm. For these polyimide films, the absorbance at 308 nm was measured using UV-1600 (manufactured by Shimadzu Corporation).

[Example 1]

In a 500ml separable flask replaced with nitrogen, 96g of N-methyl-2-pyrrolidone (NMP) and 17.71g of 4-aminophenyl-4-aminobenzoate (APAB) were charged (77.6mmol) and 4,4'-diaminodiphenylbenzene (DAS) 4.82g (19.4mmol) were stirred to dissolve APAB and DAS. Thereafter, 29.42 g (100 mmol) of biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA) was added, and the polymerization reaction was carried out with stirring under nitrogen at 80°C for 3 hours. Thereafter, it was cooled to room temperature, and the above-mentioned NMP was added to adjust the viscosity of the solution to 51,000 mPa‧s, thereby obtaining a polyamide NMP solution (hereinafter also referred to as varnish) P-1. The weight average molecular weight (Mw) of the obtained polyamide was 65,000.

[Examples 2 to 21 and Comparative Examples 1 to 5]

In Example 1, the varnish P- was obtained in the same manner as in Example 1, except that the input amount (mole ratio) of the raw materials, the type of solvent used, the polymerization temperature, and the polymerization time were changed as described in Table 1, respectively. 2~P-26.

Table 1 shows the weight average molecular weight (Mw) of the polyamic acid contained in each varnish.

The abbreviations of the components in Table 1 indicate the following meanings, respectively.

BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride

PMDA: pyromellitic dianhydride

TAHQ: p-phenylene bis (trimellitic anhydride)

APAB: 4-aminophenyl-4-aminobenzoate

ATAB: 2-methyl-4-aminophenyl-4-aminobenzoate

BABB: [4-(4-aminobenzyl)oxyphenyl] 4-aminobenzoate

BAFL: 9,9-bis(aminophenyl) stilbene

BFAF: 9,9-bis(4-amino-3-fluorophenyl) stilbene

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

DAS: 4,4'-diaminodiphenyl sulfone

NMP: N-methyl-2-pyrrolidone

DMF: N,N-dimethylformamide

DMAc: N,N-dimethylacetamide

The varnishes P-1 to P-26 obtained in the above examples and comparative examples were directly used as the resin composition, and evaluation was performed according to the above method. The evaluation results are shown in Table 2.

As shown in Tables 1 and 2, the polyimide film-based films obtained in Comparative Examples 1 and 2 containing only the structural unit represented by the general formula (1) are brittle, and physical properties such as elongation cannot be evaluated. In addition, the residual stress also becomes a higher result. In addition, the polyimide film obtained in Comparative Example 3 containing only the structural unit represented by the general formula (2) has a high residual stress, warpage occurs after the inorganic film is formed, and the elongation is also low.

On the other hand, the polyimide obtained in Examples 1 to 21 containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) at a molar ratio of 99/1 to 1/99 The film system has the result that the yellowness is as low as 20 or less, the residual stress is also as low as 25 MPa or less, and the elongation is as high as 20% or more. Also, warpage after the formation of the inorganic film did not occur, or even a small amount.

From the results of Table 2 above, it was confirmed that the polyimide resin film obtained from the resin composition of the present invention is a resin film having a low yellowness, a low residual stress, and excellent mechanical properties.

Specifically, in the present invention, a resin film having a residual stress of 25 MPa or less, a yellowness YI of 30 or less, and an elongation of 15% or more can be obtained.

[Example 22]

N-methyl-2-pyrrolidone (NMP) (water content 250 mass ppm) was added to a 500ml separable flask replaced with nitrogen immediately after opening from an 18L tank in an amount equivalent to 17wt% of solid content. In it, 5.71 g (25.0 mmol) of 4-aminophenyl-4-aminobenzoate (APAB, purity 99.5%, manufactured by Nippon Pure Chemical Co., Ltd.) was charged and stirred to dissolve APAB. Thereafter, 7.36 g (25.0 mmol) of biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by MANAC Co., Ltd.) was added, and the mixture was flowed under nitrogen at 80°C at 80°C. The polymerization reaction was carried out with stirring for 3 hours. After that, it was cooled to room temperature, and the above-mentioned NMP was added to adjust the viscosity of the solution to 51,000 mPa‧s to obtain a polyamide NMP solution (hereinafter also referred to as varnish) P-27. The weight average molecular weight (Mw) of the obtained polyamide was 128,000, and the content of molecules with a molecular weight of less than 1,000 was 0.01% by mass.

[Examples 23 to 33 and Comparative Examples 6 to 11]

In Example 22 above, except that the type of raw materials, the amount of raw materials input, the type of solvent used, the polymerization temperature and the polymerization time were changed as described in Table 3, varnish P- was obtained in the same manner as in Synthesis Example 1. 28~P-44.

Table 3 also shows the weight average molecular weight (Mw) of the polyamic acid contained in each varnish.

The abbreviations of the components in Table 3 indicate the following meanings, respectively.

BPDA: Biphenyltetracarboxylic dianhydride, 99.5% purity, manufactured by Mitsubishi Chemical Corporation

TAHQ: p-phenylene bis (trimellitic anhydride), purity 99.5%, manufactured by MANAC Co., Ltd.

PMDA: pyromellitic dianhydride

APAB: 4-aminophenyl-4-aminobenzoate, purity 99.5%

4,3-APAB: 4-aminophenyl-3-aminobenzoate, purity 99.5%

ATAB: 2-methyl-4-aminophenyl-4-aminobenzoate

BABB: [4-(4-aminobenzyl)oxyphenyl] 4-aminobenzoate

NMP1: user immediately after opening 18L can, water content 250ppm

NMP2: If the 500ml bottle is opened for one month, the water content is 3,070ppm

DMF: Open the latter in 500ml bottle, the moisture content is 3510ppm

DMAc: Open the latter in 500ml bottle, the moisture content is 3430ppm

[Examples 22 to 33 and Comparative Examples 6 to 11]

The varnishes P-27 to P-44 obtained in the above examples and comparative examples were directly used as the resin composition, and evaluation was performed according to the above method. The evaluation results are shown in Table 4.

As shown in Tables 3 and 4, Comparative Example 6 (P-39), Comparative Example 7 (P-40), and Comparative Example 8 with a weight average molecular weight of the polyimide precursor (varnish) of 3,000 or less In (P-41), Comparative Example 10 (P-43) and Comparative Example 11 (P-44), the residual stress was large and the warpage was also large. In addition, the yellowness is large, and the elongation and breaking strength are also small. In particular, in Comparative Examples 10 and 11 with a large amount of water, the film was very brittle.

On the other hand, in Comparative Example 9 (P-42) where the weight average molecular weight of the polyimide precursor is 30,000 or more, the residual stress and warpage are small, the yellowness is also low, and the elongation and breaking strength are also It is large, but the coating property is poor.

On the other hand, in Examples 22 to 33 using polyimide precursors P-27 to P-38 with a weight average molecular weight of 30,000 or more and 300,000 or less, the residual stress is low, the warpage is also small, and yellow The degree is low, the elongation and breaking strength are also large, and any characteristic has obtained excellent results.

From the results in Table 4 above, it was confirmed that the polyimide resin film obtained from the resin composition of the present invention is a resin film having a low yellowness, a low residual stress, and excellent mechanical properties.

Specifically, in the present invention, a resin film having a residual stress of 25 MPa or less, a yellowness YI of 20 or less, a glass transition temperature of 400° C. or more, an elongation of 15% or more, and a breaking strength of 250 MPa or more can be obtained.

In Examples 34 to 45 disclosed below, the effect of adding at least one selected from the group consisting of surfactants and alkoxysilane compounds to the resin composition was tested.

[Example 34]

First, the varnish P-27 obtained in the above Example 22 was directly used as the resin composition, and the evaluation of the coating stripes was performed according to the following procedure.

<Evaluation of coating stripes (coatability)>

Using a bar coater, the above resin composition was applied onto an alkali-free glass substrate (size 37×47 mm, thickness 0.7 mm) so that the film thickness after curing became 15 μm. After coating, after leaving at room temperature for 10 minutes, it was visually confirmed whether coating streaks occurred on the obtained coating film. The coating was performed three times using the same resin composition, and the number of coating streaks was checked for each coating film, and the average value was used for evaluation according to the following criteria.

◎: Continuous coating stripes with a width of 1 mm or more and a length of 1 mm or more are 0 (the evaluation of coating stripes is "excellent")

○: The above coating stripes are 1 or 2 (the evaluation of coating stripes is "good")

△: The above-mentioned coating stripes are 3~5 (the evaluation of coating stripes is "can")

The evaluation results are shown in Table 5.

[Examples 35 to 45]

After adding the types and amounts of surfactants or alkoxysilane compounds shown in Table 5 as additional additives to the varnish P-27 obtained in the above Example 22, they were filtered with a 0.1 μm filter. Thus, a resin composition is prepared.

Using the above resin composition, the evaluation of the coating stripes was performed in the same manner as in Example 34. The results are shown in Table 5.

The abbreviations of the components in Table 5 respectively indicate the following meanings. The usage amounts of these components in Table 5 are the blending amounts (usage amounts) with respect to 100 parts by mass of the polyimide precursor contained in the varnish, respectively. In Examples 39 and 45, the surfactant 1 and the alkoxysilane compound 1 were used in combination.

Surfactant 1: DBE-821, product name, polysiloxane-based surfactant, manufactured by Gelest

Surfactant 2: MEGAFAC F171, product name, fluorine-based surfactant, manufactured by DIC

Alkoxysilane compound 1: compound represented by the following general formula (AS-1)

Alkoxysilane compound 2: compound represented by the following general formula (AS-2)

As shown in Table 5, in Examples 35 to 39 and 41 to 45 containing a surfactant or an alkoxysilane compound, compared with Examples 34 and 40 which did not contain, coating streaks occurred This is suppressed, and a polyimide resin film excellent in surface smoothness can be obtained.

[Example 46]

Using a bar coater, the varnish P-27 was applied on an alkali-free glass substrate (size 37×47 mm, thickness 0.7 mm) so that the film thickness after curing became 10 μm, and then pre-baked at 140° C. for 60 minutes. Then, a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B) was used to adjust the oxygen concentration in the storage to 10 mass ppm or less, and heat curing treatment was carried out at 430°C for 1 hour. Glass substrate of polyimide resin film. An amorphous silicon layer is formed on the polyimide film, dehydrogenation annealing is performed at 430°C for 1 hour, and then an excimer laser is irradiated, thereby forming an LTPS layer. The excimer laser (wavelength 308 nm, repetition frequency 300 Hz) peeled off the glass substrate to obtain a laminate including a polyimide film and an LTPS layer.

The laminate had no warpage and the yellowness was 20 or less.

[Example 47]

A laminate was obtained in the same manner as in Example 46 except that varnish P-1 was used. The laminate had no warpage and the yellowness was 20 or less.

[Comparative Example 12]

A laminate was obtained in the same manner as in Example 46 except that varnish P-24 was used. The laminate had a large warpage and cracked part of the polyimide film.

[Synthesis example]

In a separable flask equipped with a Dean-Stark device and a refluxer, 2.24 g (9.8 mmol) of APAB, 16.14 g of NMP and 50 g of toluene were charged under a nitrogen atmosphere, and APAB was dissolved under stirring. 2.24 g (10.0 mmol) of H-PMDA was added thereto, and after refluxing at 180°C for 2 hours, toluene as an azeotropic solvent was removed in 3 hours. The contents of the flask were cooled to 40°C, and the absorption (C=O) near 1,650 cm ^-1 derived from the amide bond was confirmed by IR. After that, APAB 8.95g (39.2mmol), NMP 121.6g, PMDA 6.54g (30.0mmol) and 6FDA 4.44g (10.0mmol) were added and stirred at 80°C for 4 hours, thereby obtaining polyimide-polyamide Acid polymer varnish (P-45). The weight average molecular weight (Mw) of the resulting polyimide-polyamide acid polymer was 82,000.

[Examples 48 to 53, Comparative Example 13]

The organic EL substrate shown in FIG. 1 was produced.

Using a bar coater, the polyimide precursor varnish (P-1, P-11, P-20, P-22, P-27, P-33, P-45) was cured to a film thickness of 10 μm After being coated on a plain glass substrate (thickness 0.7mm), pre-baked at 140°C for 60 minutes. Then, a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B) was used to adjust the oxygen concentration in the storage to 10 mass ppm or less, and heat curing treatment was carried out at 430°C for 1 hour. Glass substrate of polyimide resin film.

Subsequently, the SiN layer was formed into a film with a thickness of 100 nm by CVD (Chemical Vapor Deposition) method.

Subsequently, titanium was formed into a film by sputtering, and then patterned by photolithography to form scanning signal lines.

Next, a SiN layer is formed on the entire glass substrate on which the scanning signal lines are formed by a CVD method with a thickness of 100 nm. (Think of the lower substrate 2a so far)

Then, an amorphous silicon layer 256 is formed on the lower substrate 2a, dehydrogenation annealing is performed at 430°C for 1 hour, and then an excimer laser is irradiated, thereby forming an LTPS layer.

Thereafter, photosensitive acrylic is applied on the entire surface of the lower substrate 2a by spin coating The resin is exposed and developed by photolithography to form 258 with a plurality of contact holes 257. The contact hole 257 exposes a part of each LTPS 256.

Secondly, the ITO film is formed on the entire surface of the lower substrate 2a on which the interlayer insulating film 258 is formed, exposed and developed by photolithography, and patterned by etching to match with each LTPS The lower electrodes 259 are formed in pairs.

In addition, in each contact hole 257, the lower electrode 252 penetrating through the interlayer insulating film 258 is electrically connected to the LTPS 256.

Next, after the partition wall 251 is formed, the hole transport layer 253 and the light-emitting layer 254 are formed in each space defined by the partition wall 251. In addition, the upper electrode 255 is formed so as to cover the light-emitting layer 254 and the partition wall 251. The organic EL substrate 25 is produced through the above steps.

Next, the periphery of the sealing substrate 2b in which the glass substrate, the polyimide film of this embodiment, and the SiN layer are sequentially formed is coated with an ultraviolet curing resin, and the sealing substrate 2b and the organic EL substrate are bonded in an argon atmosphere. This encloses an organic EL element. Thereby, a hollow portion 261 is formed between each organic EL element and the sealing substrate 2b.

An excimer laser (wavelength 308 nm, repetition frequency 300 Hz) is irradiated to the lower substrate 2a side and the sealing substrate 2b side of the laminated body formed in this way, and peeled off with the minimum energy required to peel off the entire surface.

Evaluation of the presence or absence of substrate warpage, lighting test, and white cloudiness evaluation of the laminate after peeling off the laminate. In addition, a thermal cycle test is also carried out. The results are shown in Table 6.

<substrate warpage>

◎: No warpage

○: Only a small amount of warpage

△: Curled due to warpage

<Lighting test>

○: Lighter

×: Unlit

<Evaluation of laminated body turbidity>

After the layered product was formed, the transparent device as a whole was regarded as ○, the slightly cloudy was regarded as △, and the cloudy was regarded as ×.

<Thermal Cycle Test>

Using a thermal cycle tester manufactured by Espec, the appearance was observed after performing 1000 cycle tests at -5°C and 60°C for 30 minutes (the moving time of the tank was 1 minute) respectively.

Those without peeling or bulging were regarded as ○, those with only a part of peeling or bulging observed after the test were regarded as △, and those with overall peeling or bulging observed after the test were regarded as ×.

[Examples 54 to 58, Comparative Example 14]

When using the polyimide precursor varnish (P-1, P-11, P-20, P-22, P-27, P-33, P-45) for the manufacture of the above laminates, except that the LTPS is changed to Other than IGZO, the laminate was manufactured, and the above test was conducted. The results are shown in Table 7.

[Examples 59 to 63, Comparative Example 15]

For providing polyimide precursor varnishes (P-1, P-11, P-20, YI of 20 or less, 308nm absorbance of 0.6 or more and 2.0 or less, and elongation of 15% or more at a thickness of 0.1 microns) P-27, P-33, P-45), the dust (ash) when irradiated with the minimum energy required for laser stripping during the above laser stripping and the energy obtained by adding the minimum energy plus 10mJ/cm ² Evaluation. Those who did not produce dust at all were regarded as ○, those who observed a small amount of dust were regarded as △, and those who observed dust as a whole were regarded as ×. The results are shown in Table 8.

The present invention is not limited to the above-mentioned embodiments, and can be implemented with various changes without departing from the gist of the invention.

[Industry availability]

The resin film formed from the polyimide precursor of the present invention can be applied to semiconductors in addition to, for example In addition to bulk insulating films, TFT-LCD insulating films, electrode protective films, etc., they can also be used as substrates in the manufacture of flexible displays, ITO electrode substrates for touch panels, etc.

Claims (20)

A polyimide precursor, which is (a2) a polyimide precursor, which contains a structural unit represented by the following general formula (10):

Moreover, the weight average molecular weight is 30,000 or more and 300,000 or less, {wherein, X ₃ represents a tetravalent group derived from p-phenylene bis(trimellitic anhydride); R ₁ , R ₂ , and R ₃ each independently represent carbon An organic group of 1 to 20 monovalent; n represents 0 or 1; and a, b, and c are integers of 0 to 4}, which satisfy the following requirements (1), and/or the following requirements (2) The polyimide precursor used for the transparent polyimide film, requirements (1): the yellowness of the above film when the film thickness is 10 μm is less than 30, requirements (2): when the film thickness of the above film is 0.1 μm The absorbance at 308 nm is 0.6 or more and 2.0 or less. The polyimide precursor according to claim 1, wherein the content of the above-mentioned (a2) polyimide precursor has a weight average molecular weight of less than 1,000 molecules and a content of less than 5 mass%. The polyimide precursor according to claim 1 or 2, wherein n in the general formula (10) is 0. A polyimide precursor, which is (a1) a polyimide precursor, which contains 1/99≦(mole number of structural unit L/mole number of structural unit M)≦99/1: The structural unit L represented by the general formula (1):

{In the formula, X ₁ represents a tetravalent group with a carbon number of 4 to 32; R ₁ , R ₂ and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b and c are integers from 0 to 4}; and the structural unit M represented by the following general formula (2):

{In the formula, X ₂ represents a tetravalent group with a carbon number of 4 to 32; Y is at least one selected from the group consisting of the following general formulas (3), (4) and (5)}, wherein the above X _1. X ₂ is derived from pyromellitic dianhydride (PMDA), 4,4′-oxydiphthalic dianhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA) and p-extended benzene A tetravalent organic group of at least one of the group consisting of bis(trimellitic anhydride),

{In the formula, R ₄ ~R ₁₁ independently represent a monovalent organic group with a carbon number of 1~20; Z is at least one of methylene, ethylidene, ether, ketone, or a single bond; d~k is 0 Integer of ~4}, which is a polyimide precursor for transparent polyimide film that meets the following requirements (1) and/or (2), requirements (1): The yellowness at a film thickness of 10 μm is 30 or less, and requirement (2): The absorbance at 308 nm at a film thickness of 0.1 μm of the above film is 0.6 or more and 2.0 or less. A resin composition characterized in that it contains a polyimide precursor according to any one of claims 1 to 4 and (b) an organic solvent. The resin composition according to claim 5, which further contains at least one selected from the group consisting of (c) surfactants and (d) alkoxysilane compounds. A polyimide containing a structural unit represented by the following general formula (11):

{In the formula, X ₁ and X ₂ are four-valent bases with carbon numbers 4 to 32; R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group with carbon numbers 1 to 20; n indicates 0 or 1; And a, b, and c are integers from 0 to 4; Y is at least one selected from the group consisting of the following general formulas (3), (4), and (5); l, m independently represent 1 or more Integer, satisfying 0.01≦l/(l+m)≦0.99},

[化9]

{In the formula, R ₄ ~R ₁₁ independently represent a monovalent organic group with a carbon number of 1-20; d~k is an integer of 0~4}, which satisfies the following requirements (1), and/or the following Requirements (2) Polyimide for transparent polyimide film, Requirements (1): The yellowness of the above film when the film thickness is 10 μm is 30 or less, Requirements (2): The film thickness of the above film is 0.1 μm The absorbance at 308 nm at the time is 0.6 or more and 2.0 or less. A polyimide containing a structural unit represented by the following general formula (12):

{In the formula, X ₃ represents a source selected from the group consisting of 4,4'-oxydiphthalic dianhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA) and p-phenylene bis(trimellitic anhydride) At least one tetravalent group in the group formed; R ₁ , R ₂ , and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b, and c are 0~4 integer}, and the elongation rate is 15% or more, which is a polyimide for transparent polyimide film that satisfies the following requirements (1) and/or the following requirements (2), requirements (1): The yellowness of the above film at a thickness of 10 μm is 30 or less. Requirements (2): The absorbance of 308 nm at a thickness of 0.1 μm of the above film is 0.6 or more and 2.0 or less. A method of manufacturing a resin film, characterized in that it includes the steps of: forming a coating film by coating the surface of the support with the resin composition according to claim 5 or 6; by applying the support and the above A step of heating the coating film to imidate the polyimide precursor contained in the coating film to form a polyimide resin film; and a step of peeling the polyimide resin film from the support . The method for producing a resin film according to claim 9, wherein before the step of peeling the polyimide resin film from the support, a step of irradiating the laser from the side of the support is performed. A method for manufacturing a laminate, characterized in that it includes the steps of: forming a coating film by coating the surface of the support with the resin composition as in claim 5 or 6; and The step of forming the polyimide resin film by heating the support and the coating film to imide the polyimide precursor contained in the coating film. A method for manufacturing a display substrate, characterized in that it includes the steps of: forming a coating film by coating a resin composition such as claim 5 or 6 on the surface of a support; by applying the support and the above A step of heating the coating film to imide the polyimide precursor contained in the coating film to form a polyimide resin film; a step of forming an element or a circuit on the polyimide resin film; And the step of peeling the polyimide resin film on which the element or circuit is formed from the support. A polyimide film for display, which contains a polyimide represented by the following general formula (12):

{In the formula, X ₃ is a structure derived from p-phenylene bis (trimellitic anhydride), R ₁ , R ₂ and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b and c are integers from 0 to 4}, which are polyimide films for transparent polyimide films that satisfy the following requirements (1) and/or (2) Requirements (1): The yellowness of the above film at a thickness of 10 μm is 30 or less, and Requirements (2): The absorbance of 308 nm at a thickness of the above film of 0.1 μm is 0.6 or more and 2.0 or less. A laminate comprising a transparent polyimide film layer and a low-temperature polysilicon TFT layer. The transparent polyimide film layer contains a polyimide represented by the following general formula (13):

{In the formula, X ₁ represents a tetravalent group with a carbon number of 4 to 32; R ₁ , R ₂ and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b and c are integers from 0 to 4}, and X ₁ is derived from pyromellitic dianhydride (PMDA), 4,4'-oxydiphthalic dianhydride (ODPA), and biphenyltetracarboxylic acid A tetravalent organic group of at least one of the group consisting of acid dianhydride (BPDA) and p-phenylene bis (trimellitic anhydride), the above-mentioned laminate meets the following requirements (1), and/or the following requirements (2), requirements (1): the above-mentioned transparent polyimide film layer has a yellowness of 30 or less at a thickness of 10 μm, and requirements (2): the above-mentioned transparent polyimide film layer has a thickness of 308 nm at a thickness of 0.1 μm The absorbance is 0.6 or more and 2.0 or less. The laminated body according to claim 14, wherein the yellowness YI value of the polyimide film layer at a thickness of 10 μm is 30 or less. The laminate according to claim 14, wherein the elongation of the polyimide film layer is 15% or more. A polyimide film, characterized in that it contains polyimide as claimed in claim 7 or 8, and the yellowness of the film thickness of 10 microns after heating above 400°C is 20 or less, and the film thickness is 308nm when the film thickness is 0.1 microns The absorbance is 0.6 or more and 2.0 or less, and the elongation is 15% or more. A resin composition comprising: (a) a polyimide precursor represented by the following general formula (1), (b) an organic solvent, and selected from (c) a surfactant and (d) an alkoxy group At least one of the group consisting of silane compounds, and X ₁ is derived from pyromellitic dianhydride (PMDA), 4,4′-oxydiphthalic dianhydride (ODPA), biphenyltetracarboxy A tetravalent organic group of at least one of the group consisting of acid dianhydride (BPDA) and p-phenylene bis (trimellitic anhydride),

{In the formula, X ₁ represents a tetravalent group with a carbon number of 4 to 32; R ₁ , R ₂ and R ₃ independently represent a monovalent organic group with a carbon number of 1 to 20; n represents 0 or 1; and a, b and c are integers from 0 to 4}, which is a resin composition for a transparent polyimide film that satisfies the following requirements (1) and/or the following requirements (2), requirement (1): above The yellowness of the film when the film thickness is 10 μm is 30 or less, and the requirement (2): The absorbance at 308 nm when the film thickness of the film is 0.1 μm is 0.6 or more and 2.0 or less. The resin composition according to claim 18, wherein the polyimide film obtained by heating the above resin composition has a yellowness YI value of 30 or less when the film thickness is 10 μm. The resin composition according to claim 18, wherein the polyimide film obtained by heating the resin composition has an elongation of 15% or more.

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