KR102133559B1 - Polyimide precursor, resin composition, and method for producing resin film - Google Patents

Abstract

{식 중, X₁ 은 탄소수 4 ∼ 32 의 4 가의 기를 나타낸다. R₁, R₂, R₃ 은 각각 독립적으로 탄소수 1 ∼ 20 의 1 가의 유기기를 나타낸다. n 은 0 또는 1 을 나타낸다. 그리고 a 와 b 와 c 는 0 ∼ 4 의 정수이다.} 로 나타내는 구조 단위 L 과,
하기 일반식 (2)：

{식 중, X₂ 는 탄소수 4 ∼ 32 의 4 가의 기를 나타낸다.} 로 나타내는 구조 단위 M 을, 1/99 ≤ (구조 단위 L 의 몰수/구조 단위 M 의 몰수) ≤ 99/1 로 포함하는, 폴리이미드 전구체.(a1) The following general formula (1):

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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. Structural units L represented by },
The following general formula (2):

{In the formula, X ₂ represents a tetravalent group having 4 to 32 carbon atoms.} The structural unit M represented by 1/99 ≤ (molar number of structural units L/molar number of structural units M) ≤ 99/1 is included, Polyimide precursor.

Description

Manufacturing method of polyimide precursor, resin composition and resin film {POLYIMIDE PRECURSOR, RESIN COMPOSITION, AND METHOD FOR PRODUCING RESIN FILM}

The present invention relates to, for example, a method for producing a polyimide precursor, a resin composition, and a resin film used for manufacturing a substrate for a flexible device.

Generally, a film of a polyimide resin is used as a resin film in applications requiring high heat resistance. The general polyimide resin is a high heat resistance produced by preparing a polyimide precursor by solution polymerization of an aromatic carboxylic acid anhydride and an aromatic diamine, followed by thermal imidization at a high temperature or chemical imidization using a catalyst. It is resin.

The polyimide resin is an insoluble and infusible super-heat-resistant resin, and has excellent properties such as heat oxidation resistance, heat resistance, radiation resistance, low temperature resistance, and chemical resistance. For this reason, polyimide resins are used in a wide range of fields including electronic materials. Examples of the application of the polyimide resin in the field of electronic materials include, for example, insulating coating agents, insulating films, semiconductor protective films, and TFT-LCD electrode protective films. In recent years, adoption as a colorless and transparent flexible substrate utilizing its lightness and flexibility has been studied instead of a glass substrate conventionally used in the field of display materials.

When manufacturing a polyimide resin film as a flexible substrate, a polyimide resin film is obtained by applying a composition containing a polyimide precursor on a suitable support to form a coating film, followed by heat treatment and imidization. As the support, glass, silicon, silicon nitride, silicon oxide, metal, or the like is used, for example. When manufacturing a laminate having a polyimide film on such a support, heat treatment at a high temperature of 250° C. or higher is required for drying and imidization of the polyimide precursor. By this heat treatment, residual stress is generated in the laminate, and serious problems such as bending and peeling occur. This is because the coefficient of linear thermal expansion of the polyimide is greater than that of the material constituting the support.

As a polyimide material having a small coefficient of thermal expansion, polyimide formed from 3,3',4,4'-biphenyltetracarboxylic dianhydride and paraphenylenediamine is best known. Although it depends on the film thickness and manufacturing conditions, it has been reported that this polyimide film exhibits a very low coefficient of linear thermal expansion (Non-Patent Document 1).

Moreover, since the polyimide which has an ester structure in a molecular chain has moderate linearity and rigidity, it has been reported to show a low linear thermal expansion coefficient (patent document 1).

However, general polyimide resins, including the polyimide described in the above-mentioned documents, are colored in brown or yellow due to high aromatic ring density, so that the light transmittance in the visible light region is low, and thus transparency is required. It is difficult to use on. For example, the polyimide of the non-patent document 1 obtained from 3,3',4,4'-biphenyltetracarboxylic dianhydride and paraphenylenediamine has a yellowness (YI at a film thickness of 10 µm). Chi) is higher than 40, and is insufficient in terms of transparency.

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

Japanese Patent No. 4627297 Japanese Patent Publication No. 2010-538103 Japanese Patent No. 3079867

The latest polyimide Japan Polyimide Research Association N T S

However, in order to apply the polyimide resin as a colorless transparent flexible substrate, in addition to transparency, mechanical properties such as excellent elongation and breaking strength are also required. In particular, in recent years, with the device type of the TFT being LTPS (low temperature polysilicon TFT), a film that exhibits the above physical properties has been desired even in a thermal history higher than that of the prior art.

However, the physical properties of known transparent polyimide are not sufficient for use as a heat-resistant colorless transparent substrate for displays.

Further, as confirmed by the present inventors, although the polyimide resin described in Patent Document 1 exhibited a low linear thermal expansion coefficient, the yellowness (YI value) of the polyimide resin film after peeling was high, and the residual stress was high. It has been found that there are problems that the elongation is low and the breaking strength is low.

As for the yellowness, the polyimide film described in Patent Literature 2 shows a low yellowness in a temperature range of about 300°C, but a yellowness (YI value) significantly deteriorates in a high temperature region of 400°C or higher. there was.

Further, as a polyimide having a low linear expansion coefficient, a polyimide composed of 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 has a very soft film to be applied as a flexible substrate, and there is room for improvement in the yellowness at high temperature.

The present invention has been made in view of the problems described above. Accordingly, an object of the present invention is to provide a polyimide resin film having 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.

[One]

(a1) The following general formula (1):

[Formula 1]

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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. Structural units L represented by },

The following general formula (2):

[Formula 2]

{In the formula, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is a structural unit M represented by at least one member selected from the group consisting of the following general formulas (3), (4) and (5),

1/99 ≤ (number of moles of structural unit L/number of moles of structural unit M) ≤ 99/1

Characterized in that it comprises, a polyimide precursor.

[Formula 3]

[Formula 4]

[Formula 5]

{In the formula, R ₄ to R ₁₁ each independently represent a monovalent organic group having 1 to 20 carbon atoms. d to k are integers from 0 to 4}

[2]

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

[3]

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

[4]

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

[5]

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

[6]

(a2) The following general formula (10):

[Formula 6]

A polyimide precursor having a structural unit represented by and having a weight average molecular weight of 30,000 or more and 300,000 or less.

{Wherein, X ₃ is 4,4'-oxydiphthalic anhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA), and 4,4'-biphenylbis(trimellitic acid monoesteric anhydride ) (TAHQ), a tetravalent group derived from at least one selected from the group consisting of. 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.}

[7]

The polyimide precursor according to [6], wherein the content of the molecule of the weight average molecular weight less than 1,000 in the polyimide precursor (a2) is less than 5% by mass.

[8]

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

[9]

The X ₁ , X ₂ is pyromellitic dianhydride (PMDA), 4,4'-oxydiphthalic anhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA), and 4,4'-ratio The polyimide precursor according to any one of [1] to [5], which is a tetravalent organic group derived from at least one selected from the group consisting of phenylbis (trimellitic acid monoester acid anhydride) (TAHQ).

[10]

The resin composition comprising the polyimide precursor according to any one of [1] to [9], and (b) an organic solvent.

[11]

Moreover, the resin composition as described in [10] which contains at least 1 sort(s) selected from the group which consists of (c) surfactant and (d) alkoxysilane compound,.

[12]

The following general formula (11):

[Formula 7]

{In the formula, X ₁ and X ₂ represent a tetravalent group having 4 to 32 carbon atoms. 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 member selected from the group consisting of the following general formulas (3), (4) and (5). l and m each independently represent an integer of 1 or more, and satisfies 0.01≦l/(l+m)≦0.99.} A polyimide characterized by having a structural unit represented by.

[Formula 8]

[Formula 9]

[Formula 10]

{In the formula, R ₄ to R ₁₁ each independently represent a monovalent organic group having 1 to 20 carbon atoms. d to k are integers from 0 to 4}

[13]

The following general formula (12):

[Formula 11]

{Wherein, X ₃ is 4,4'-oxydiphthalic anhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA), and 4,4'-biphenylbis(trimellitic acid monoesteric anhydride ) (TAHQ), a tetravalent group derived from at least one selected from the group consisting of. 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 of 0 to 4. A polyimide having a structural unit represented by} and having an elongation of 15% or more.

[14]

A step of forming a coating film by applying the resin composition according to [10] or [11] on the surface of the support;

Heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film;

Step of peeling the polyimide resin film from the support

It characterized in that it comprises, a method for producing a resin film.

[15]

The manufacturing method of the resin film as described in [14] which performs the process of irradiating a laser from the said support side, before the process of peeling the said polyimide resin film from the said support body.

[16]

A step of forming a coating film by applying the resin composition according to [10] or [11] on the surface of the support;

Step of forming a polyimide resin film by imidizing the polyimide precursor contained in the coating film by heating the support and the coating film

It characterized in that it comprises, a method for producing a laminate.

[17]

A step of forming a coating film by applying the resin composition according to [10] or [11] on the surface of the support;

Heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film;

Forming a device or a circuit on the polyimide resin film;

Step of peeling the polyimide resin film on which the device or circuit is formed from the support

Characterized in that it comprises, a method of manufacturing a display substrate.

[18]

The following general formula (12):

[Formula 12]

{Wherein, X ₃ is 4,4'-oxydiphthalic anhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA), and 4,4'-biphenylbis(trimellitic acid monoesteric anhydride ) (TAHQ) and at least one member selected from the group consisting of, R ₁ , R ₂ , 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.}

A polyimide film for display, comprising a polyimide represented by.

[19]

The following general formula (13):

[Formula 13]

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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 of 0 to 4. A layered product comprising a polyimide film layer containing a polyimide represented by} and a low-temperature polysilicon TFT layer.

[20]

Yellowness at a film thickness of 10 microns after heating at 400°C or higher is 20 or less, absorbance at 308 nm at a film thickness of 1 micron is 0.6 or more and 2.0 or less, and elongation is 15% or more. , Polyimide film.

[21]

(a) the polyimide precursor represented by the following general formula (1),

(b) an organic solvent,

(c) at least one member selected from the group consisting of surfactants and (d) alkoxysilane compounds

Resin composition comprising a.

[Formula 14]

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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.}

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

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

Hereinafter, exemplary embodiments of the present invention (hereinafter abbreviated as "embodiments") will be described in detail. In addition, this invention is not limited to the following embodiment, It can be implemented by various modification within the range of the summary. In addition, it is intended that the characteristic value described in this disclosure is a value measured by a method understood by a person skilled in the art or the method described in the section of [Example] or equivalent thereto unless otherwise specified.

<resin composition>

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

Hereinafter, each component is demonstrated in order.

[Polyimide precursor]

The polyimide precursor as the first aspect of this embodiment,

(a1) The following general formula (1):

[Formula 15]

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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. Structural units L represented by },

The following general formula (2):

[Formula 16]

{In the formula, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is a structural unit M represented by at least one selected from the group consisting of the following general formulas (3), (4) and (5)}

It is a polyimide precursor characterized by including 1/99<(molar number of structural units L/molar number of structural units M)<99/1.

[Formula 17]

[Formula 18]

[Formula 19]

{In the formula, R ₄ to R ₁₁ each independently represent a monovalent organic group having 1 to 20 carbon atoms. d to k are integers from 0 to 4}

When the polyimide precursor of the first aspect of the present embodiment is a polyimide film, residual stress is low, bending is small, yellowness (YI value) is small, and elongation is high. In addition, when the polyimide precursor of the first aspect of the present embodiment is a polyimide film, yellowness (YI value) in a 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 group, ethyl group and propyl group, halogen-containing groups such as trifluoromethyl group, alkoxy groups such as methoxy group and ethoxy group. Among these, a methyl group is preferred from the viewpoint of YI in the high temperature region.

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

Here, n is 0 or 1. Of these, 0 is preferred from the viewpoint of YI in the high temperature region.

Moreover, the lower limit of the molar ratio of the structural unit L and the structural unit M (the number of moles of the structural unit L/the number of moles of the structural unit M) may be 5/95, 10/90, 20/80, or 30/70 It may be 40/60. The upper limit of the molar ratio of the structural unit L to the structural unit M (molar number of structural units L/molar number of structural units M) may be 95/5, 90/10, 80/20, or 70/30. 60/40 may be sufficient.

X ₁ and X ₂ are independently a tetravalent group having 4 to 32 carbon atoms, and may be the same or different. The tetravalent organic group derived from the following tetracarboxylic dianhydride is illustrated.

Specifically, as the tetracarboxylic dianhydride, an aromatic tetracarboxylic dianhydride having 8 to 36 carbon atoms, an aliphatic tetracarboxylic dianhydride having 6 to 36 carbon atoms, and an alicyclic having 6 to 36 carbon atoms The compound selected from the formula tetracarboxylic dianhydride can be illustrated. Of these, aromatic tetracarboxylic dianhydrides having 8 to 36 carbon atoms are preferred from the viewpoint of yellowness in the high temperature region. The number of carbons referred to herein includes the number of carbons contained in the carboxyl group.

More specifically, as an aromatic tetracarboxylic dianhydride having 8 to 36 carbon atoms, for example, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (hereinafter also referred to as 6FDA), 5- (2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2dicarboxylic anhydride, pyromellitic dianhydride (hereinafter also referred to as PMDA), 1,2, 3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (hereinafter also referred to as BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 2,2 ',3,3'-biphenyltetracarboxylic dianhydride, methylene-4,4'-diphthalic acid 2 anhydride, 1,1-ethylidene-4,4'-diphthalic acid 2 anhydride, 2,2-propyl Liden-4,4'-diphthalic acid 2 anhydride, 1,2-ethylene-4,4'-diphthalic acid 2 anhydride, 1,3-trimethylene-4,4'-diphthalic acid 2 anhydride, 1,4-tetra Methylene-4,4'-diphthalic anhydride, 1,5-pentamethylene-4,4'-diphthalic anhydride, 4,4'-oxydiphthalic anhydride (hereinafter also referred to as ODPA), p- Phenylenebis (trimellitate anhydride) (hereinafter also referred to as TAHQ) Thio-4,4'-diphthalic acid 2 anhydride, sulfonyl-4,4'-diphthalic acid 2 anhydride, 1,3-bis(3, 4-dicarboxyphenyl)benzene 2 anhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene 2 anhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene 2 anhydride, 1, 3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene 2 anhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene 2 anhydride, Bis[3-(3,4-dicarboxyphenoxy)phenyl]methane 2 anhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane 2 anhydride, 2,2-bis[3-(3 ,4-dicarboxyphenoxy)phenyl]propane 2 anhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane 2 anhydride, bis(3,4-dicarboxyphenoxy)dimethyl Silane 2 anhydride, 1,3-bis (3,4) -Dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane 2 anhydride, 2,3,6,7-naphthalenetetracarboxylic acid 2 anhydride, 1,4,5,8-naphthalenetetracarboxylic acid 2 anhydride, 1,2,5,6-naphthalenetetracarboxylic acid 2 anhydride, 3,4,9,10-perylenetetracarboxylic acid 2 anhydride, 2,3,6,7-anthracenetetracarboxylic acid 2 And anhydrides, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, and the like.

Examples of the aliphatic tetracarboxylic dianhydride having 6 to 50 carbon atoms include, for example, ethylenetetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride and the like;

As alicyclic tetracarboxylic dianhydride having 6 to 36 carbon atoms, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexane-1, 2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride (hereinafter referred to as CHDA), 3,3',4,4'-ratio Cyclohexyltetracarboxylic dianhydride, carbonyl-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) 2 anhydride, methylene-4,4'-bis(cyclohexane-1,2- Dicarboxylic acid) 2 anhydride, 1,2-ethylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) 2 anhydride, 1,1-ethylidene-4,4'-bis( Cyclohexane-1,2-dicarboxylic acid) 2 anhydride, 2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) 2 anhydride, oxy-4,4' -Bis(cyclohexane-1,2-dicarboxylic acid) 2 anhydride, thio-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) 2 anhydride, sulfonyl-4,4'- Bis(cyclohexane-1,2-dicarboxylic acid) dihydrate, 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-dicar And carboxylic acid anhydride phenyl) ether.

From the viewpoint of the balance of CTE, chemical resistance, Tg and yellowness in the high temperature region, PMDA, BPDA, TAHQ, and ODPA are preferred, and BPDA and TAHQ are more preferred.

The polyimide precursor in the embodiment may be used as a polyamideimide precursor by using dicarboxylic acid in addition to the above-described tetracarboxylic dianhydride in a range that does not impair its performance. By using such a precursor, in the obtained film, various performances such as improvement in mechanical elongation, improvement in glass transition temperature, and reduction in yellowness can be adjusted. Examples of such dicarboxylic acids include dicarboxylic acids having an aromatic ring and alicyclic dicarboxylic acids. It is particularly preferable that it is at least one compound selected from the group consisting of an aromatic dicarboxylic acid having 8 to 36 carbon atoms and an alicyclic dicarboxylic acid having 6 to 34 carbon atoms. The number of carbons referred to herein includes the number of carbons contained in the carboxyl group.

Of these, dicarboxylic acids having aromatic rings are preferred.

Specifically, for example, isophthalic acid, terephthalic acid, 4,4'-biphenyldicarboxylic acid, 3,4'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 1, 4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-sulfonylbisbenzoic acid, 3, 4'-sulfonylbisbenzoic acid, 3,3'-sulfonylbisbenzoic acid, 4,4'-oxybisbenzoic acid, 3,4'-oxybisbenzoic acid, 3,3'-oxybisbenzoic acid, 2,2-bis (4-carboxyphenyl)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)fluorene, 9, 9-bis(4-(3-carboxyphenoxy)phenyl)fluorene, 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)biphenyl, 3, 3'-bis(3-carboxyphenoxy)biphenyl, 4,4'-bis(4-carboxyphenoxy)-p-terphenyl, 4,4'-bis(4-carboxyphenoxy)-m-ter Phenyl, 3,4'-bis(4-carboxyphenoxy)-p-terphenyl, 3,3'-bis(4-carboxyphenoxy)-p-terphenyl, 3,4'-bis(4-carboxy Phenoxy)-m-terphenyl, 3,3'-bis(4-carboxyphenoxy)-m-terphenyl, 4,4'-bis(3-carboxyphenoxy)-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)-m-terphenyl, 3,3'-bis(3-carboxyphenoxy)-m-terphenyl, 1,1-cyclobutanedicar Carboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 1,3-phenylene diacetic acid, 1,4- Phenylene diacetic acid, etc.; and

And 5-aminoisophthalic acid derivatives described in the pamphlet of International Publication No. 2005/068535. In the case where these dicarboxylic acids are actually copolymerized with the polymer, they may be used in the form of acid chlorides derived from thionyl chloride or the like, and active esters.

As for the weight average molecular weight (Mw) of the polyimide precursor in this embodiment, 10,000-300,000 are preferable, and 30,000-200,000 are especially preferable. When the weight average molecular weight is greater than 10,000, mechanical properties such as elongation and breaking strength are excellent, residual stress is low, and YI is low. When the weight average molecular weight is less than 300,000, it is easy to control the weight average molecular weight at the time of synthesis of the polyamic acid, and a resin composition having a suitable viscosity can be obtained, and the coatability of the resin composition is improved. In this disclosure, a weight average molecular weight is a value calculated|required as a standard polystyrene conversion value using gel permeation chromatography (hereinafter also referred to as GPC).

In the polyimide precursor in the present embodiment, the content of the molecule having a molecular weight of less than 1,000 is preferably less than 5% by mass and more preferably less than 1% by mass relative to the total amount of the polyimide precursor. The polyimide film formed from the resin composition obtained using such a polyimide precursor has a low residual stress and is preferable from the viewpoint of lowering the haze of the inorganic film formed on the polyimide film.

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

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

[Formula 20]

(In the formula, 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.)

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

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

More specifically, when n is 0, 4-aminophenyl-4-aminobenzoate (APAB), 2-methyl-4-aminophenyl-4-aminobenzoate (ATAB), 4-aminophenyl-3 -Aminobenzoate (4,3-APAB) and the like can be exemplified.

When n is 1, [4-(4-aminobenzoyl)oxyphenyl]4-aminobenzoate etc. can be illustrated.

The diamine represented by the following general formula (7) can be illustrated as a diamine used for the structural unit represented by general formula (3) in this embodiment.

[Formula 21]

(In the formula, R ₄ and R ₅ each 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 independently monovalent organic groups having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl group, ethyl group and propyl group, halogen-containing groups such as trifluoromethyl group, alkoxy groups such as methoxy group and ethoxy group. Among these, a methyl group is preferred from the viewpoint of YI in the high temperature region.

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

More specifically, 4,4'-diaminodiphenylsulfone and 3,3'-diaminodiphenylsulfone can be exemplified.

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

[Formula 22]

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

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

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

Z can be exemplified by a single bond, methylene group, ethylene group, ether, or ketone. Among these, a single bond is more preferable from the viewpoint of YI in the high temperature region.

More specifically, 9,9-bis(aminophenyl)fluorene, 9,9-bis(4-amino-3-methylphenyl)fluorene, 9,9-bis(4-amino-3-fluorophenyl) Fluorene, 9,9-bis(4-hydroxy-3-aminophenyl)fluorene, 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, etc. can be exemplified, among which It is preferable to use one or more selected.

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

[Formula 23]

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

Moreover, if j and k are each independently integers of 0-4, they will not be limited. Among them, an integer of 0 to 2 is preferred from the viewpoint of YI and residual stress, and 0 is particularly preferred from the viewpoint of YI in the high temperature region.

More specifically, 2,2'-bis(trifluoromethyl)benzidine etc. can be illustrated.

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

As a second aspect of this embodiment,

(a2) The following general formula (10):

[Formula 24]

A polyimide precursor having a structural unit represented by and having a weight average molecular weight of 30,000 or more and 300,000 or less can be provided.

{Wherein, X ₃ is 4,4'-oxydiphthalic anhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA), and 4,4'-biphenylbis(trimellitic acid monoesteric anhydride ) (TAHQ), a tetravalent group derived from at least one selected from. 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, but 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 group, ethyl group and propyl group, halogen-containing groups such as trifluoromethyl group, alkoxy groups such as methoxy group and ethoxy group. Among these, a methyl group is preferred from the viewpoint of YI in the high temperature region.

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

Here, n is 0 or 1. Of these, 0 is preferred from the viewpoint of YI in the high temperature region.

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

The weight average molecular weight (Mw) of the polyimide precursor in the second aspect is 30,000 to 300,000. When the weight average molecular weight is greater than 30,000, mechanical properties such as elongation and breaking strength are excellent, residual stress is low, and YI is low. When the weight average molecular weight is less than 300,000, it is easy to control the weight average molecular weight at the time of synthesis of the polyamic acid, and a resin composition having a suitable viscosity can be obtained, and the coatability of the resin composition is improved. Of these, the weight average molecular weight (Mw) is more preferably 35000 or more and 250,000 or less, and particularly preferably 40000 or more and 230,000 or less.

In the polyimide precursor in the second aspect of the present embodiment, the content of the molecule having a molecular weight of less than 1,000 is preferably less than 5% by mass and more preferably less than 1% by mass relative to the total amount of the polyimide precursor. The polyimide film formed from the resin composition obtained using such a polyimide precursor has a low residual stress and is preferable from the viewpoint of lowering the haze of the inorganic film formed on the polyimide film.

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

The polyimide precursor of the second aspect of the present embodiment has excellent storage stability and excellent coating properties. Moreover, the polyimide film formed from the polyimide precursor of the second aspect of the present embodiment has low residual stress, low warpage, small yellowness (YI value), high elongation, and high breaking strength.

In addition to the diamines represented by the general formulas (6) to (9) described above, the polyimide precursors in the first aspect and the second aspect do not inhibit elongation, strength, stress, and yellowness. Diamines can be used.

Other diamines include, for example, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide, 3,3' -Diaminodiphenyl sulfide, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3, 4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 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]sulfone, 4,4-bis(4-aminophenoxy)biphenyl, 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 )Phenyl)propane, 2,2-bis[4-(4-aminophenoxy)phenyl)hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, and the like. It is preferable to use one or more of them.

The content of the other diamine in all diamines is preferably 20 mol% or less, and particularly preferably 10 mol% or less.

[Preparation of polyimide precursor]

The polyimide precursor (polyamic acid) of the present invention includes tetracarboxylic dianhydride, a diamine (for example, APAB) used in the structural unit represented by the general formula (1), and the general formula (2). ) Can be synthesized by polycondensation reaction of a diamine (for example, 4,4'-DAS) used for the structural unit represented by ). It is preferable to perform this reaction in a suitable solvent. Specifically, for example, after dissolving a predetermined amount of APAB and 4,4'-DAS in a solvent, a predetermined amount of tetracarboxylic dianhydride is added to the obtained diamine solution, followed by stirring. .

Of the diamine components, the molar ratio of diamine used in the structural unit represented by the general formula (1) and the diamine used in the structural unit represented by the general formula (2) is not limited as long as it is 99/1 to 1/99. Among diamine components, when the diamine used for the structural unit represented by the general formula (2) is 1 mol% or more, yellowness tends to be good, and the diamine used for the structural unit represented by the general formula (1) is 1 mol% or more. There is a tendency that the warpage after forming the inorganic film on the resulting polyimide film is good. The molar ratio of diamine used in the structural unit represented by the general formula (1) and the diamine used in the structural unit represented by the general formula (2) is preferably 95/5 to 50/50, and 90/10 to 50/50 is It is more preferable. The molar ratio of diamine used in the structural unit represented by the general formula (1) and the diamine used in the structural unit represented by the general formula (2) may be 80/20 to 50/50, or 70/30 to 50/50 do. It is preferable to make the molar ratio of the diamine used for the structural unit represented by general formula (1) more than the molar ratio of the diamine used for the structural unit represented by general formula (2).

In addition, the polyimide precursor of the second aspect of the present embodiment includes tetracarboxylic dianhydride (for example, TAHQ) and diamine (for example, APAB) used for the structural unit represented by the general formula (6) described above. It can be synthesized by a polycondensation reaction. It is preferable to perform this reaction in a suitable solvent. Specifically, for example, after dissolving a predetermined amount of APAB in a solvent, a predetermined amount of TAHQ is added to the obtained diamine solution, followed by stirring.

The ratio (molar ratio) of the tetracarboxylic dianhydride component and the diamine component when synthesizing the polyimide precursor is the thermal expansion coefficient, residual stress, elongation, and yellowness (hereinafter, also referred to as YI) of the resulting resin film. From the viewpoint of controlling) to a desired range, it is preferable to be in the range of tetracarboxylic dianhydride:diamine = 100:90 to 100:110 (diamine 0.90 to 1.10 molar part relative to 1 mole of tetracarboxylic dianhydride). , 100:95 to 100:105 (diamine 0.95 to 1.05 mol parts with respect to 1 mol part of acid anhydride) is more preferable.

In the present embodiment, when synthesizing a polyamic acid which is a preferred polyimide precursor, the molecular weight is adjusted by adjusting the ratio of the tetracarboxylic dianhydride component and the diamine component, and adding a terminal blocker (i). It is possible to control. The molecular weight of the polyamic acid can be increased as the ratio of the acid anhydride component to the diamine component approaches 1:1, and the amount of the terminal blocker used is small.

It is recommended to use a high-purity product as the tetracarboxylic dianhydride component and diamine component. The purity is preferably 98% by mass or more, more preferably 99% by mass or more, and even more preferably 99.5% by mass or more. In the case where a plurality of types of acid anhydride components or diamine components are used in combination, it is sufficient to have the above-mentioned purity as a whole of the acid 2 anhydride components or diamine components. It is desirable to have a purity of.

The solvent for the reaction is not particularly limited as long as it is a solvent in which a tetracarboxylic dianhydride component and a diamine component and the generated polyamic acid can be dissolved, and a high molecular weight polymer is obtained. Specific examples of such a solvent include aprotic solvents, phenolic solvents, ether and glycol solvents, and the like. As specific examples of these,

As the aprotic solvent, for example, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N-methylcapro Lactam, 1,3-dimethylimidazolidinone, tetramethylurea, the following general formula (13):

[Formula 25]

Amide-based solvents such as Ecamide M100 represented by R ₁₂ =methyl group (trade name: manufactured by Idemitsu Heungsan), and Ecamide B100 represented by R ₁₂ =n-butyl group (trade name: manufactured by Idemitsu Heungsan);

lactone-based solvents such as γ-butyrolactone and γ-valerolactone;

A phosphorus-based amide-based solvent such as hexamethylphosphoricamide and hexamethylphosphine triamide;

Sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane;

Ketone solvents such as cyclohexanone and methylcyclohexanone;

Tertiary amine solvents such as picoline and pyridine;

Ester solvents such as acetic acid (2-methoxy-1-methylethyl)

My back:

As the phenolic solvent, for example, 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, etc.:

As the ether and glycol solvent, for example, 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-( 2-methoxyethoxy)ethyl]ether, tetrahydrofuran, 1,4-dioxane, etc.,

Each can be lifted.

The boiling point at normal pressure of the solvent used for the synthesis of the polyamic acid 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, a drying process is required for a long time. On the other hand, when the boiling point of the solvent is lower than 60°C, roughness on the surface of the resin film and mixing of bubbles into the resin film may occur during the drying step, and a uniform film may not be obtained.

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

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

You may use these solvents individually or in mixture of 2 or more types.

It is preferable that the content of the molecule|numerator of molecular weight less than 1,000 in (a) polyimide precursor in this embodiment is less than 5 mass %.

(a) It is considered that the presence of a molecule having a molecular weight of less than 1,000 in the polyimide precursor is due to the fact that the amount of the solvent used in the synthesis is involved. That is, it is considered that the acid anhydride group of a part of the acid anhydride monomer is hydrolyzed by moisture to become a carboxyl group and remains in a low molecular state without high molecular weight. Therefore, it is preferable that the water content of the solvent used in the polymerization reaction is as small as possible. The water content of this solvent is preferably 3,000 ppm by mass or less, and more preferably 1,000 ppm by mass or less.

The water content of the solvent is the grade of the solvent used (dehydration grade, general purpose grade, etc.), solvent container (bottle, 18 liter can, canister can, etc.), storage condition of the solvent (with or without rare gas encapsulation), from opening to use. It is considered that time (used immediately after opening, used after a time has elapsed since opening, etc.), etc. are involved. In addition, it is considered that the replacement of the rare gas in the reactor before synthesis and the presence or absence of the distribution of the rare gas during synthesis are also involved. Therefore, (a) When synthesizing the polyimide precursor, it is necessary to use a high-purity product as a raw material, use a solvent with a low moisture content, and take measures to prevent moisture from entering the system from entering the system before and during the reaction. Is recommended

When dissolving each monomer component in a solvent, you may heat as needed.

(a) The reaction temperature at the time of synthesizing the polyimide precursor is preferably 0°C to 120°C, more preferably 40°C to 100°C, and further preferably 60 to 100°C. By carrying out the polymerization reaction at this temperature, a polyimide precursor having a high degree of polymerization is 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 having a uniform polymerization degree is obtained, and by setting it to 100 hours or less, a polyimide precursor having a high polymerization degree can be obtained.

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

(a) After the solution obtained by dissolving the polyimide precursor in a solvent (for example, N-methyl-2-pyrrolidone) is applied to the surface of the support, the solution is added under a nitrogen atmosphere (for example, an oxygen concentration of 2,000 ppm). In the resin obtained by imidizing the polyimide precursor by heating (for example, 1 hour) at 300 to 550°C (for example, 430°C) in the following nitrogen, the yellowness in the 10 µm film thickness 30 or less.

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

The polyimide precursor according to the present embodiment is, if necessary, within the range that does not impair the desired performance of the present invention, the following general formula (14):

[Formula 26]

{In General Formula (14), a plurality of R _13s are each independently a hydrogen atom, a C 1 to C 20 monovalent aliphatic hydrocarbon, or a monovalent aromatic group,

X ₄ is a tetravalent organic group having 4 to 32 carbon atoms,

Y is a divalent organic group having 4 to 32 carbon atoms. only,

The structural unit corresponding to the said General formula (1) and said General formula (6) is excluded. You may further contain the polyimide precursor which has a structure represented by }.

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

It is preferable that the mass ratio of the polyimide precursor which has the structural unit represented by general formula (14) in (a) polyimide precursor which concerns on this embodiment is 80 mass% or less with respect to all of (a) polyimide precursor. It is more preferable that it is 70 mass% or less from a viewpoint of a fall of oxygen dependence of YI value and total light transmittance.

In a preferable aspect of this embodiment, a part of (a1) polyimide precursor and (a2) polyimide precursor may be imidized. The imidation rate in this case is preferably 80% or less, and more preferably 50% or less. This partial imidization is obtained by heating (a) the polyimide precursor and dehydrating the waste ring. The heating is preferably 120 to 200°C, more preferably 150 to 180°C, preferably 15 minutes to 20 hours, more preferably 30 minutes to 10 hours.

Further, N,N-dimethylformamidedimethylacetal or N,N-dimethylformamidediethylacetal is added to the polyamic acid obtained by the above-described reaction, heated, and part or all of the carboxylic acid is esterified. Then, by using as the polyimide precursor (a) in the present embodiment, a resin composition with improved viscosity stability at room temperature can also be obtained. In addition, these ester-modified polyamic acids are sequentially reacted with the above-described acid dihydride component with an equivalent of a monohydric alcohol equivalent to an acid anhydride group and a dehydrating condensing agent such as thionyl chloride and dicyclohexylcarbodiimide. It can also be obtained by a condensation reaction with a diamine component after being prepared.

The proportion of the polyaimide precursor (preferably polyamic acid) in the resin composition of the present embodiment is preferably 3 to 50% by mass, more preferably 5 to 40% by mass from the viewpoint of coatability. , 10 to 30 mass% is particularly preferred.

<resin composition>

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

[(b) Organic solvent]

The organic solvent (b) in the present embodiment is not particularly limited as long as it can dissolve the above-mentioned (a) polyimide precursor and other components optionally used. As such (b) organic solvent, the above-mentioned thing can be used as a solvent which can be used for the synthesis of (a) polyimide precursor. Preferred organic solvents are also the same as above. The organic solvent (b) in the resin composition of the present embodiment may be the same as or different from the solvent used in the synthesis of (a) the polyimide precursor.

(b) It is preferable to make the organic solvent into the quantity which becomes 3-50 mass% of solid content concentration of a resin composition. Moreover, it is preferable to add after adjusting (b) the structure and quantity of an organic solvent so that the viscosity (25 degreeC) of a resin composition becomes 500 mPa*s-100,000 mPa*s.

[Other ingredients]

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

The resin composition according to the present embodiment includes at least one member selected from the group consisting of (a) a polyimide precursor, (b) an organic solvent, (c) a surfactant, and (d) an alkoxysilane compound.

The skeleton of the polyimide precursor is not limited to the skeleton described above in the first and second aspects. 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).

[Formula 27]

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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)

By adding surfactant to the resin composition of this embodiment, the coating property of the resin composition can be improved. Specifically, generation of streaks in the coating film can be prevented.

Examples of such surfactants include silicone-based surfactants, fluorine-based surfactants, and nonionic surfactants other than these. These examples are:

As a silicone surfactant, For example, organosiloxane polymers KF-640, 642, 643, KP341, X-70-092, X-70-093, (above, trade names, manufactured by Shin-Etsu Chemical Co., Ltd.), SH-28PA, SH-190, SH-193, SZ-6032, SF-8428, DC-57, DC-190 (above, trade names, manufactured by Toray Dow Corning and Silicon), SILWET L-77, L-7001, FZ-2105 , FZ-2120, FZ-2154, FZ-2164, FZ-2166, L-7604 (above, trade name, 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 (above, trade name, BIC Chemie・Japan manufactured), Granol (trade name, manufactured by Kyoeisha Chemical Co., Ltd.);

As the fluorine-based surfactant, for example, Megapak F171, F173, R-08 (manufactured by Dainippon Ink Chemical Industry Co., Ltd., trade name), Fluorad FC4430, FC4432 (Sumitomo 3M Co., Ltd., trade name) and the like;

As nonionic surfactants other than these, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether and the like are listed.

Among these surfactants, silicone surfactants and fluorine surfactants are preferred from the viewpoint of coatability (stripes suppression) of the resin composition, and from the viewpoint of the effect on the YI value and total light transmittance by oxygen concentration during the curing process, silicone-based Surfactants are preferred.

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

(d) alkoxysilane compounds

In order to make the resin film obtained from the resin composition which concerns on this embodiment show sufficient adhesiveness with a support body in the manufacturing process, such as a flexible device, the resin composition is (a) 100 mass% of polyimide precursors. , The alkoxysilane compound may contain 0.01 to 20% by mass. When the content of the alkoxysilane compound to 100 mass% of the polyimide precursor is 0.01 mass% or more, good adhesion to the support can be obtained. Moreover, it is preferable from a viewpoint of storage stability of a resin composition that content of an alkoxysilane compound is 20 mass% or less. The content of the alkoxysilane compound is more preferably 0.02 to 15% by mass, more preferably 0.05 to 10% by mass, and particularly preferably 0.1 to 8% by mass, with respect to 100 parts by mass of the polyimide precursor.

By using an alkoxysilane compound as an additive of the resin composition according to the present embodiment, in addition to the above-mentioned improvement in adhesion, and also improves the coatability (suppression of streaky non-uniformity) of the resin composition, cure oxygen of the YI value of the resulting cured film Concentration dependence can be reduced.

Examples of the alkoxysilane compound include 3-ureidpropyltriethoxysilane, bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, γ -Aminopropyltrimethoxysilane, γ-aminopropyltripropoxysilane, γ-aminopropyltributoxysilane, γ-aminoethyltriethoxysilane, γ-aminoethyltripropoxysilane, γ-aminoethyltribu Methoxysilane, γ-aminobutyltriethoxysilane, γ-aminobutyltrimethoxysilane, γ-aminobutyltripropoxysilane, γ-aminobutyltributoxysilane, phenylsilanetriol, trimethoxyphenylsilane, Trimethoxy(p-tolyl)silane, diphenylsilanediol, dimethoxydiphenylsilane, diethoxydiphenylsilane, dimethoxydi-p-tolylsilane, triphenylsilanol, and alkoxysilane compounds represented by the following structures Etc. are mentioned, It is preferable to use 1 or more types chosen from these.

[Formula 28]

The manufacturing method of the resin composition in this embodiment is not specifically limited. For example, the following method can be followed.

When the solvent used when (a) the polyimide precursor is synthesized and the organic solvent (b) are the same, the synthesized polyimide precursor solution can be used as the resin composition. Moreover, if necessary, in the temperature range of room temperature (25°C) to 80°C, one or more of (b) an organic solvent and other components are added to the polyimide precursor, stirred and mixed, and then used as a resin composition. May be For the stirring and mixing, a suitable device such as a three-one motor (manufactured by Shinto Chemical Co., Ltd.) equipped with a stirring blade, a rotating revolution mixer, or the like can be used. Moreover, you may apply heat of 40-100 degreeC as needed.

On the other hand, in the case where (a) the solvent used when synthesizing the polyimide precursor and (b) the organic solvent are different, the solvent in the synthesized polyimide precursor solution can be appropriately used, for example, by reprecipitation or solvent distillation removal After removal by (a) isolating the polyimide precursor, the resin composition may be prepared by adding and stirring and mixing (b) an organic solvent and other components as necessary in a temperature range of room temperature to 80°C.

After preparing the resin composition as described above, a part of the polyimide precursor is already dehydrated to such an extent that the polymer does not cause precipitation by heating the composition solution at, for example, 5 minutes to 2 hours at 130 to 200°C. You may dedicate. Here, the imidation rate can be controlled by controlling the heating temperature and the heating time. By partially imidizing the polyimide precursor, the viscosity stability at the time of storage of the resin composition at room temperature can be improved. The range of the imidation ratio is preferably 5% to 70% from the viewpoint of balancing the solubility of the polyimide precursor with the resin composition solution and storage stability of the solution.

It is preferable that the water content of the resin composition which concerns on this embodiment is 3,000 mass ppm or less.

The moisture content of the resin composition is more preferably 1,000 ppm by mass or less, and more preferably 500 ppm by mass or less, from the viewpoint of viscosity stability when the resin composition is stored.

The solution viscosity of the resin composition according to the present 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. This solution viscosity can be measured using an E-type viscometer (made by Toki Sangyo Co., Ltd., VISCONICEHD). When the solution viscosity is lower than 300 mPa·s, application at the time of film formation is difficult, and when the solution viscosity is higher than 200,000 mPa·s, there is a concern that agitation during synthesis becomes difficult.

(a) When synthesizing the polyimide precursor, even if the solution has a high viscosity, it is possible to obtain a resin composition having good handleability by adding a solvent and stirring after the completion of the reaction.

The resin composition of this embodiment has the following characteristics in a preferable aspect.

After coating the resin composition on the surface of the support to form a coating film, the coating film is contained in the coating film by heating in a nitrogen atmosphere (for example, in nitrogen having an oxygen concentration of 2,000 ppm or less) at 300°C to 550°C. The resin film obtained by imidizing the polyimide precursor to be obtained has a yellowness YI of 30 or less in a 10 µm film thickness.

After coating the resin composition on the surface of the support to form a coating film, the coating film is contained in the coating film by heating in a nitrogen atmosphere (for example, in nitrogen having an oxygen concentration of 2,000 ppm or less) at 300°C to 550°C. The resin film obtained by imidizing the polyimide precursor to be formed has a residual stress of 25 MPa or less.

The resin composition according to the present embodiment can be suitably used, for example, to form transparent substrates for display devices such as liquid crystal displays, organic electroluminescent displays, field emission displays, and electronic paper. Specifically, it can be used to form a substrate of a thin film transistor (TFT), a substrate of a color filter, a substrate of a transparent conductive film (ITO, IndiumThinOxide), or the like.

Since the resin precursor of this embodiment can form a polyimide film having a residual stress of 25 MPa or less, it is easy to apply to a display manufacturing process provided with a TFT element device on a colorless transparent polyimide substrate.

<resin film>

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

Moreover, another aspect of this invention provides the method of manufacturing a resin film from the above-mentioned resin composition.

The resin film in this embodiment,

A step of forming a coating film by applying the aforementioned resin composition on the surface of the support (coating step),

A step of heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film (heating process);

Step of peeling the polyimide resin film from the support (peeling step)

It characterized in that it comprises a.

Here, the support is not particularly limited as long as it has heat resistance at the heating temperature of the subsequent steps and good peelability. For example, a glass (eg, alkali-free glass) substrate;

Silicon wafer;

PET (polyethylene terephthalate), OPP (stretched polypropylene), polyethylene glycol terephthalate, polyethylene glycol naphthalate, polycarbonate, polyimide, polyamideimide, polyetherimide, polyetheretherketone, polyethersulfone, polyphenylene Resin substrates such as sulfone and polyphenylene sulfide;

Metal substrates such as stainless steel, alumina, copper and nickel

Etc. are used.

In the case of forming a film-like polyimide molded body, for example, a glass substrate or a silicon wafer is preferable, and when forming a film- or sheet-like polyimide molded body, for example, PET (polyethylene Terephthalate), OPP (stretched polypropylene), etc. are preferred.

As the coating method, for example, a coating method such as a doctor blade knife coater, an air knife coater, a roll coater, a rotary coater, a flow coater, a die coater, a bar coater, a spin coat, a spray coat, or a dip coat; Printing techniques such as screen printing and gravure printing can be applied.

The coating thickness should be appropriately adjusted depending on the thickness of the desired resin film and the content of the polyimide precursor in the resin composition, but is preferably about 1 to 1,000 μm. Although the coating process is sufficient at room temperature, the resin composition may be heated in the range of 40 to 80°C for the purpose of lowering the viscosity and improving workability.

Following the coating step, a drying step may be performed, or the drying step may be omitted to directly proceed to the next heating step. This drying step is performed for the purpose of removing the organic solvent. When performing a drying process, suitable apparatus, such as a hot plate, a box dryer, and a conveyor dryer, can be used, for example. It is preferable to perform a drying process at 80-200 degreeC, and it is more preferable to carry out at 100-150 degreeC. The drying time is preferably 1 minute to 10 hours, more preferably 3 minutes to 1 hour.

As described above, a coating film containing a polyimide precursor is formed on the support.

Subsequently, a heating step is performed. The heating step is a step in which the organic solvent remaining in the coating film is removed in the drying step and the imidization reaction of the polyimide precursor in the coating film is performed to obtain a film made of polyimide.

This heating process can be performed, for example, using an apparatus such as an inert gas oven, a hot plate, a box dryer, or a conveyor dryer. This step may be performed simultaneously with the drying step, or both steps may be performed sequentially.

Although the heating process may be performed under an air atmosphere, it is recommended to perform under an inert gas atmosphere from the viewpoint of safety, transparency of the resulting polyimide film, and YI value. As an inert gas, nitrogen, argon, etc. are mentioned, for example.

Although the heating temperature may be appropriately set depending on the type of the organic solvent (b), 250°C to 550°C is preferable, and 300 to 450°C is more preferable. If it is 250°C or higher, imidization becomes sufficient, and if it is 550°C or lower, there is no problem such as deterioration in transparency or deterioration of heat resistance of the resulting polyimide film. It is preferable to set heating time to about 0.5 to 3 hours.

In the present embodiment, the oxygen concentration in the ambient atmosphere in the heating step is preferably 2,000 mass ppm or less, more preferably 100 mass ppm or less, and more preferably 10 mass, from the viewpoints of transparency and YI value of the resulting polyimide film. ppm or less is more preferable. By heating in an atmosphere having an oxygen concentration of 2,000 ppm by mass or less, the YI value of the resulting polyimide film can be 30 or less.

Depending on the purpose and purpose of use of the polyimide resin film, a peeling step of peeling the resin film from the support is required after the heating step. It is preferable to perform this peeling process, after cooling the resin film on a support body to room temperature-about 50 degreeC.

As this peeling process, the following aspect (1)-(4) is mentioned, for example.

(1) A polyimide resin is produced by producing a structure comprising a polyimide resin film/support by the above method, and irradiating a laser from the support side of the structure to ablation the interface between the support and the polyimide resin film. How to peel. As a type of laser, a solid (YAG) laser, a gas (UV excimer) laser, and the like can be mentioned. It is preferable to use a spectrum having a wavelength of 308 nm or the like (see Japanese Patent Publication No. 2007-512568, Japanese Patent Publication No. 2012-511173, etc.).

(2) A method of forming a release layer on the support before applying the resin composition to the support, and then obtaining a construct comprising a polyimide resin film/peeling layer/support to peel the polyimide resin film. Examples of the release layer include parylene (registered trademark, manufactured by Nippon Parylene Co., Ltd.), and a method of using tungsten oxide; a method of using a release agent such as vegetable oil, silicone, fluorine or alkyd. (See Japanese Unexamined Patent Publication 2010-67957, Japanese Unexamined Patent Publication 2013-179306, etc.).

You may use together the laser irradiation of this method (2) and said (1).

(3) A method of obtaining a polyimide resin film by etching a metal with an etchant after obtaining a construct comprising a polyimide resin film/support using a metal substrate that can be etched as a support. As a metal, copper (for example, Mitsui Metal Mining Co., Ltd. electrolytic copper foil "DFF"), aluminum, etc. can be used, for example. As the etchant, ferric chloride or the like can be used for copper, and dilute hydrochloric acid or the like can be used for aluminum.

(4) After obtaining a structure comprising a polyimide resin film/support by the above method, an adhesive film is attached to the surface of the polyimide resin film, and the adhesive film/polyimide resin film is separated from the support. After the method for separating the polyimide resin film from the adhesive film.

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

Moreover, in the method (3), when copper is used as a support, the tendency that the YI value of the resulting polyimide resin film becomes large and the elongation becomes small is seen. This is considered to be the influence of copper ions.

Although the thickness of the resin film obtained by the said method is not specifically limited, It is preferable that it is the range of 1-200 micrometers, More preferably, it is 5-100 micrometers.

In the resin film according to the present embodiment, the yellowness YI at a film thickness of 10 μm may be 30 or less. In addition, the residual stress may be 25 MPa or less. In particular, the yellowness YI at a film thickness of 10 μm may be 30 or less, and the residual stress may be 25 MPa or less. Such characteristics are, for example, the resin precursor of the present disclosure in a nitrogen atmosphere (for example, in nitrogen having an oxygen concentration of 2,000 ppm or less), preferably 300°C to 550°C, more preferably 350°C to 450 By imidizing at ℃, it is realized satisfactorily.

The resin film according to the present embodiment may also have a tensile elongation of 15% or more. The tensile elongation of the resin film may also be 20% or more, particularly 30% or more. This tensile elongation can be measured using a commercially available tensile tester using a 10 μm film-thick resin film as a sample.

The resin film according to the present embodiment is a film composed of polyimide in which the polyimide precursor (a1) contained in the above-mentioned resin composition is heat imidized. Therefore, the following general formula (11):

[Formula 29]

{In the formula, X ₁ and X ₂ represent a tetravalent group having 4 to 32 carbon atoms. 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 member selected from the group consisting of the general formulas (3), (4) and (5). l and m each independently represent an integer of 1 or more, and have a structural unit represented by 0.01 ≤ l / (l + m) ≤ 0.99.}.

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

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

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

Moreover, as a 2nd aspect, it is a film which consists of the polyimide (a2) polyimide which the polyimide precursor (a2) contained in the resin composition mentioned above was heat imidized. Therefore, the following general formula (12):

[Formula 30]

{Wherein, X ₃ is 4,4'-oxydiphthalic anhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA), and 4,4'-biphenylbis(trimellitic acid monoesteric anhydride ) (TAHQ), a tetravalent group derived from at least one selected from. 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 of 0-4.} A resin film having a structural unit represented by elongation and having an elongation of 15% or more, preferably a residual stress of 25 MPa or less, and a YI of 30 or less, The glass transition temperature is 400°C or higher, and the breaking strength is 250 MPa or higher.

<Laminated body>

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

Further, another aspect of the present invention provides a method for manufacturing the laminate.

The laminate in this embodiment,

A step of forming a coating film by applying the aforementioned resin composition on the surface of the support (coating step);

By heating the support and the coating film, it can be obtained by a method for producing a laminate, including a step (heating step) of imidizing a polyimide precursor contained in the coating film to form a polyimide resin film.

The manufacturing method of the said laminated body can be implemented by carrying out similarly to the manufacturing method of the above-mentioned resin film except not performing a peeling process, for example.

This laminated body can be used suitably for manufacture of a flexible device, for example.

It will be described in more detail below.

In the case of forming a flexible display, a glass substrate is used as a support, a flexible substrate is formed thereon, and TFT or the like is formed thereon. The process of forming a TFT or the like on the flexible substrate is typically performed at a temperature in a wide range of 150 to 650°C. However, in order to realize realistically desired performance, a TFT-IGZO (InGaZnO) oxide semiconductor or TFT (a-Si-TFT, poly-Si-TFT) is used at an elevated temperature of 250°C to 450°C using an inorganic material. ).

On the other hand, by these thermal histories, various properties (especially yellowness and elongation) of the polyimide film tend to decrease, and when it exceeds 400°C, yellowness and elongation particularly decrease. By the way, the polyimide film obtained from the polyimide precursor according to the present invention can be favorably used in the region even in a high temperature region of 400° C. or higher with very little deterioration in yellowness or elongation.

Moreover, in this embodiment, the laminated body containing the polyimide film layer containing polyimide represented by the following general formula (13) and LTPS (low temperature polysilicon TFT) layer can be provided.

[Formula 31]

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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 manufacturing method of the said laminated body, after manufacturing a laminated body containing the above-mentioned support body and the polyimide resin film formed from the above-mentioned resin composition on the surface of this support body, after forming an amorphous Si layer, 400-450 After dehydrogenation annealing for 0.5 to 3 hours at a temperature, the LTPS layer can be formed by crystallization with an excimer laser or the like. Then, the said laminated body can be obtained by peeling a glass and a polyimide film by laser peeling or the like.

The polyimide film layer containing the polyimide represented by the general formula (13), and the layered product containing the LTPS (low temperature polysilicon TFT) layer, have little peeling or swelling after a heat cycle test, and have little substrate warpage.

In addition, if the residual stress generated on the flexible substrate and the polyimide resin film is high, when the laminate composed of both expands and contracts during cooling at room temperature after expansion in a high-temperature TFT process, the warpage and breakage of the glass substrate and the flexible substrate Problems such as peeling from the glass substrate may occur. In general, since the coefficient of thermal expansion of a glass substrate is small compared to a resin, residual stress occurs between the glass substrate and the flexible substrate. As described above, the resin film according to the present embodiment can be suitably used for forming a flexible display because the residual stress generated between the glass substrate and the glass substrate can be 25 MPa or less.

The polyimide film according to the present embodiment can have a yellowness YI of 30 or less in a 10 µm film thickness and a tensile elongation of 15% or more. Thereby, the resin film which concerns on this embodiment is excellent in the breaking strength at the time of handling a flexible substrate, and therefore the yield at the time of manufacturing a flexible display can be improved.

Further, as another aspect, the yellowness at a film thickness of 10 microns after heating at 400°C or higher is 20 or less, the absorbance at 308 nm when the film thickness is 0.1 micron is 0.6 or more and 2.0 or less, and the elongation is 15 % Or more, a polyimide film can be provided.

By setting YI to 20 or less, a flexible substrate can be manufactured without deteriorating the image quality when the display is used.

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

When the absorbance of 308 nm at a film thickness of 0.1 micron 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 removed from the glass substrate with a laser. From the viewpoint of suppressing the ash after laser peeling, 0.6 or more and 1.5 or less, and elongation is preferably 20% or more, for example, from the viewpoint of not degrading the performance of the organic EL device, 0.6 or more and 1.0 or less and elongation is 20% or more Especially preferred.

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

In addition, the polyimide film may burn out with laser light when the laser is peeled off, and the remaining ash is ash.

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

Another aspect of the present invention provides a method of manufacturing the display substrate.

The manufacturing method of the display substrate in this embodiment is,

A step of forming a coating film by applying the aforementioned resin composition on the surface of the support (coating step),

A step of heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film (heating process);

A step of forming an element or circuit on the polyimide resin film (element and circuit forming step);

Step of peeling the polyimide resin film on which the device or circuit is formed from the support (peeling process)

It characterized in that it comprises a.

In the said method, a coating process, a heating process, and a peeling process can be performed in the same manner as the manufacturing method of the above-mentioned resin film, respectively.

The element/circuit formation process can be performed by a method known to those skilled in the art.

The resin film according to the present embodiment that satisfies the above properties is suitably used in applications where the use of the existing polyimide film is limited by the yellow color, in particular, a colorless transparent substrate for flexible displays, a protective film for color filters, and the like. Furthermore, for example, a diffuser sheet and a coating film (for example, an interlayer of TFT-LCD, a gate insulating film, a liquid crystal alignment film, etc.) in a protective film, TFT-LCD, etc., an ITO substrate for a touch panel, a cover glass for a smartphone It can also be used in fields such as resin substrates, where colorless transparency and low birefringence are required. When the polyimide according to the present embodiment is applied as a liquid crystal alignment film, it is possible to manufacture a TFT-LCD having a high aperture ratio and a high contrast ratio.

The polyimide precursor and the resin film and laminate obtained using the resin precursor according to the present embodiment can be applied as, for example, semiconductor insulating films, TFT-LCD insulating films, electrode protective films, and the like, and flexible device manufacturing. In particular, it can be suitably used as a substrate. Here, examples of the flexible device to which the resin film and laminate according to the present embodiment can be applied include, for example, flexible displays, flexible solar cells, flexible touch panel electrode substrates, flexible lighting, and flexible batteries.

Example

Hereinafter, the present invention will be described in more detail based on Examples, which are described for explanation, and the scope of the present invention is not limited to the following Examples.

Various evaluations in 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, for high-speed liquid chromatography, 24.8 mmol/L lithium bromide monohydrate (wako Pure Chemical Industries Co., purity 99.5%) and 63.2 m immediately before measurement) A mol/L phosphoric acid (manufactured by Wako Pure Chemical Industries Ltd., for high-speed liquid chromatography) was used. The calibration curve for calculating the weight average molecular weight was prepared using standard polystyrene (manufactured by Tosoh Corporation).

Column: Shodex KD-806M (Showa Electric Works)

Flow rate: 1.0 ml/min

Column temperature: 40 ℃

Pump: PU-2080Plus (manufactured by JASCO)

Detector: RI-2031Plus (RI: Differential refractometer, manufactured by JASCO) and UV-2075Plus (UV-VIS: Ultraviolet visible absorbometer, manufactured by JASCO)

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

The content of the molecule having a molecular weight of less than 1,000 in the resin was calculated as a ratio (percentage) of the peak area occupied by the components having a molecular weight of less than 1,000 in the peak area of the entire molecular weight distribution using the measurement results of GPC obtained above.

<Evaluation of water content>

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

<Evaluation of viscosity stability of resin composition>

Regarding the resin composition prepared in each of Examples and Comparative Examples,

After preparation, a sample left at room temperature for 3 days was used as a sample after preparation, and viscosity measurement at 23°C was carried out;

Thereafter, the sample left at room temperature for 2 weeks was used as the sample after 2 weeks, and viscosity measurement at 23°C was performed again. These viscosity measurements were performed using a viscometer (TV-22 manufactured by Toki Sangyo Co., Ltd.) with a temperature controller.

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

Viscosity change rate 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 based on the following criteria.

◎: Viscosity change rate is 5% or less (preservation stability "good")

○: Viscosity change rate is more than 5 and less than 10% (preservation stability "good")

×: Viscosity change rate exceeded 10% (preservation stability "poor")

<Evaluation of varnish coatability>

The resin composition prepared in each of Examples and Comparative Examples was coated on a non-alkali glass substrate (size 37×47 mm, thickness 0.7 mm) using a bar coater, applied to a film thickness of 15 μm after curing, and then at 140° C. And pre-baked for 60 minutes.

The coating property of the varnish was evaluated by measuring the step difference on the surface of the coating film using a step meter (manufactured by Tencor, Model P-15).

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

○: The step difference of the surface is more than 0.1 and 0.5 µm or less (coating "good")

×: The level difference of the surface was more than 0.5 µm (applicable "poor")

<Evaluation of residual stress>

Each resin composition was coated with a spin coater on a 6 inch silicon wafer having a thickness of 625 µm ± 25 µm, in which the "bending amount" was measured in advance, and prebaked at 100°C for 7 minutes. Thereafter, the oxygen concentration in the warehouse was adjusted to 10 ppm by mass or less using a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B), and heated at 430°C for 1 hour. Curing treatment (cure treatment) was performed, and a silicon wafer with a polyimide resin film having a thickness of 10 µm after curing was produced.

The warpage amount of this wafer was measured using a residual stress measuring device (manufactured by Tencor Corporation, model name FLX-2320), and the residual stress generated between the silicon wafer and the resin film was evaluated.

◎: Residual stress is ―5 sec 15 5 or less (evaluation of residual stress “excellent”)

○: Residual stress is greater than 15 and less than or equal to 25 MPa (evaluation of residual stress "good")

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

<Evaluation of warpage of the polyimide resin film formed with an inorganic film>

The resin composition prepared in each of Examples and Comparative Examples was spin-coated on a 6-inch silicon wafer substrate having an aluminum vapor-deposited layer formed on its surface so that the film thickness after curing was 10 µm, and pre-baked at 100°C for 7 minutes. Thereafter, the oxygen concentration in the warehouse was adjusted to 10 ppm by mass or less using a vertical cure (manufactured by Koyo Lindberg, model name VF-2000B), and heat-cured at 430°C for 1 hour, and poly A wafer on which a mid resin film was formed was prepared. Using this wafer, a silicon nitride (SiNx) film, which is an inorganic film, was formed on a polyimide resin film by a CVD method to a thickness of 100 nm at 350 deg. C, and a laminate wafer on which an inorganic film/polyimide resin was formed was formed. Got.

The layered wafer obtained above was immersed in a dilute hydrochloric acid aqueous solution, and two layers of an inorganic film and a polyimide film were integrally peeled from the wafer to obtain a sample of a polyimide film with an inorganic film formed on the surface. The warpage of the polyimide resin film was evaluated using this sample.

◎：There is no warpage (bending “excellent”)

○: There is only a slight bending (bending "good")

×: The film is rounded due to bending (bending "bad")

<Evaluation of yellowness (YI value)>

A wafer (one in which an inorganic film was not formed) was produced in the same manner as in <evaluation evaluation of the polyimide resin film on which an inorganic film was formed>. A resin film was obtained by immersing the wafer in a dilute hydrochloric acid solution and peeling the polyimide resin film.

About the obtained polyimide resin film, YI value (film thickness of 10 micrometers equivalent) was measured using the D65 light source with Nippon Electric Color Co., Ltd. (Spectrophotometer: SE600).

<Evaluation of elongation and breaking strength>

A wafer (one in which an inorganic film was not formed) was produced in the same manner as in <evaluation evaluation of the polyimide resin film on which an inorganic film was formed>. Using a dicing saw (DAD 3350 manufactured by Disco Co., Ltd.), a 3 mm-wide groove was placed in the polyimide resin film of the wafer, and then the resin film piece was immersed in a dilute hydrochloric acid solution overnight, and dried. This was cut to a length of 50 mm and used as a sample.

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

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

Each of the above varnishes was spin-coated on a quartz glass substrate, and heated in a nitrogen atmosphere at 430°C for 1 hour to obtain polyimide resin films each having a film thickness of 0.1 µm. About these polyimide films, the absorbance at 308 nm was measured using UV-1600 (manufactured by Shimadzu Corporation).

[Example 1]

In a nitrogen-substituted 500 ml separable flask, 96 g of N-methyl-2-pyrrolidone (NMP) was added, and 17.71 g (77.6 mmol) and 4 of 4-aminophenyl-4-aminobenzoate (APAB) were added. ,4'-diaminodiphenylsulfone (DAS) was added 4.82 g (19.4 mmol) and stirred to dissolve APAB and DAS. Subsequently, 29.42 g (100 mmol) of biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA) was added, and the polymerization reaction was performed under nitrogen flow at 80°C for 3 hours with stirring. It was carried out. Thereafter, the mixture was cooled to room temperature, and the solution viscosity was adjusted to 51,000 mPa·s by adding the NMP, thereby obtaining an NMP solution of polyamic acid (hereinafter also referred to as varnish) P-1. The weight average molecular weight (Mw) of the obtained polyamic acid was 65,000.

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

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

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

The abbreviations of each component in Table 1 are respectively the following meanings.

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

PMDA: pyromellitic anhydride

TAHQ: p-phenylene bis (trimellitate anhydride)

APAB: 4-aminophenyl-4-aminobenzoate

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

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

BAFL: 9,9-bis (aminophenyl) fluorene

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

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

DAS: 4,4'-diaminodiphenylsulfone

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 used as resin compositions as they were, and evaluated according to the methods described above. Table 2 shows the evaluation results.

As apparent from Table 1 and Table 2, the polyimide films obtained in Comparative Examples 1 and 2, which contained only the structural units represented by General Formula (1), were unable to evaluate physical properties such as elongation. Moreover, the residual stress also became a high result. Moreover, the polyimide film obtained in Comparative Example 3 containing only the structural unit represented by the general formula (2) had a high residual stress, warpage occurred after forming the inorganic film, and the elongation was also low.

On the other hand, the polyimide film obtained from Examples 1 to 21, which contains the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) in a molar ratio of 99/1 to 1/99, is yellow. The result was as low as 20 or less, the residual stress was as low as 25 MPa or less, and the elongation was as high as 20% or more. In addition, even if the warpage after forming the inorganic film did not occur or occurred, it was extremely slight.

From the results of Table 2 above, it was confirmed that the polyimide resin film obtained from the resin composition according to the present invention is a resin film having small yellowness, 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 is obtained.

[Example 22]

In an nitrogen-substituted 500 ml separable flask, N-methyl-2-pyrrolidone (NMP) (moisture content 250 mass ppm) immediately after opening of an 18-liter can was added in an amount equivalent to 17 wt% of solid content, and 4- 5.71 g (25.0 mmol) of aminophenyl-4-aminobenzoate (APAB, purity 99.5%, manufactured by Nippon Pharmaceuticals Co., Ltd.) was added and stirred to dissolve APAB. Subsequently, 7.36 g (25.0 mmol) of biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA, purity 99.5%, manufactured by Manak Co., Ltd.) was added, and it was 80°C under nitrogen flow. The polymerization reaction was carried out under stirring for 3 hours. Thereafter, the mixture was cooled to room temperature, and the solution viscosity was adjusted to 51,000 mPa·s by adding the NMP to obtain an NMP solution of polyamic acid (hereinafter also referred to as varnish) P-27. The weight average molecular weight (Mw) of the obtained polyamic acid was 128,000, and the content of the molecule with a molecular weight less than 1,000 was 0.01 mass%.

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

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

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

The abbreviation of each component in Table 3 has the following meaning respectively.

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

TAHQ: p-phenylenebis (trimellitate anhydride), purity 99.5%, manufactured by Manak Co., Ltd.

PMDA: pyromellitic anhydride

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-aminobenzoyl)oxyphenyl]4-aminobenzoate

NMP 1: 18 ℓ Can immediately after opening, water content 250 ppm

NMP 2: 500 ml Bottles left unopened for 1 month after opening, moisture content 3,070 ppm

DMF: 500 ml bottled thing after opening, moisture content 3510 ppm

DMAc: 500 ml bottled thing after opening, moisture content 3430 ppm

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

Varnishes P-27 to P-44 obtained in the above Examples and Comparative Examples were used as resin compositions as they were, and evaluated according to the methods described above. Table 4 shows the evaluation results.

As is apparent from Tables 3 and 4, Comparative Example 6 (P-39), Comparative Example 7 (P-40), and Comparative Example 8 (P-41) having a weight average molecular weight of 3,0000 or less of the polyimide precursor (varnish) ), Comparative Example 10 (P-43) and Comparative Example 11 (P-44) had a large residual stress and a large warpage. Moreover, yellowness was large, elongation and breaking strength were also small. In particular, in Comparative Examples 10 and 11 with a large amount of moisture, the membrane was very wet.

On the other hand, in Comparative Example 9 (P-42) in which the weight average molecular weight of the polyimide precursor was 30,0000 or more, the residual stress and bending were small, the yellowness was low, the elongation and the breaking strength were also large, but the applicability was poor. .

On the other hand, in Examples 22 to 33 using the polyimide precursors P-27 to P-38 having a weight average molecular weight of 30,000 or more and 300,000 or less, the residual stress is low, the bending is small, the yellowness is low, the elongation and Excellent results were obtained in any of the properties, which also had a high breaking strength.

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

Specifically, in the present invention, the 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. This is obtained.

In Examples 34 to 45 shown below, experiments were conducted on the effect when at least one selected from the group consisting of a surfactant and an alkoxysilane compound was added to the resin composition.

[Example 34]

First, using the varnish P-27 obtained in Example 22 as a resin composition as it was, evaluation of coating streaks was performed by the following procedure.

<Evaluation of coating streaks (coating properties)>

The above resin composition was coated on a non-alkali glass substrate (size 37 x 47 mm, thickness 0.7 mm) using a bar coater so that the film thickness after curing was 15 µm. After coating, after standing at room temperature for 10 minutes, it was visually confirmed whether coating streaks were not generated in the obtained coating film. Three coatings were performed using the same resin composition, and the number of coating stripes was examined for each coating film, and evaluation was performed based on the following criteria using the average value.

◎: 0 coating stripes having a width of 1 mm or more and a length of 1 mm or more in succession (evaluation of coating stripes "good")

○: 1 or 2 coating stripes above (evaluation "good" for coating stripes)

△: 3 to 5 coating stripes above (evaluation of coating stripes "good")

Table 5 shows the evaluation results.

[Examples 35 to 45]

A resin composition was prepared by adding a surfactant and an alkoxysilane compound of the kind and amount shown in Table 5 as additional additives to the varnish P-27 obtained in Example 22, respectively, and then filtering through a 0.1 µm filter.

Using the above resin composition, coating stripes were evaluated in the same manner as in Example 34. Table 5 shows the results.

The abbreviation of each component in Table 5 has the following meaning respectively. The usage-amount of these components in Table 5 is the compounding quantity (consumption amount) with respect to 100 mass parts of polyimide precursors contained in varnish, respectively. In Examples 39 and 45, surfactant 1 and alkoxysilane compound 1 were used in combination.

Surfactant 1: DBE-821, product name, silicone surfactant, Gelest production

Surfactant 2: Megapak F171, product name, fluorine-based surfactant, DIC production

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

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

[Formula 32]

As is clear from Table 5, in Examples 35 to 39 and Examples 41 to 45 containing a surfactant or an alkoxysilane compound, generation of coating streaks was suppressed compared to Examples 34 and 40 not containing, It was found that a polyimide resin film excellent in surface smoothness was obtained.

[Example 46]

The varnish P-27 was applied onto an alkali-free glass substrate (size 37×47 mm, thickness 0.7 mm) using a bar coater, and then cured to a thickness of 10 μm, followed by pre-baking at 140° C. for 60 minutes. Subsequently, the oxygen concentration in the warehouse was adjusted to 10 ppm or less by using a vertical cure (manufactured by Koyo Lindbergh, model name VF-2000B), followed by heat curing treatment at 430°C for 1 hour, and polyimide. A glass substrate on which a resin film was formed was prepared. An amorphous silicon layer was formed on this polyimide film, dehydrogenation was performed at 430°C for 1 hour, and the LTPS layer was formed by continuously irradiating an excimer laser. The glass substrate was peeled off with an excimer laser (wavelength 308 nm, repetition frequency 300 Hz) to obtain a laminate comprising a polyimide film and an LTPS layer.

This laminate had no warpage and a yellowness of 20 or less.

[Example 47]

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

[Comparative Example 12]

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

[Synthesis example]

In a separable flask equipped with a Dean Stark apparatus and a reflux, 2.24 g (9.8 mmol) of APAB, 16.14 g of NMP and 50 g of toluene were added under nitrogen atmosphere, and APAB was dissolved under stirring. To this, 2.24 g (10.0 mmol) of H-PMDA was added, refluxed at 180° C. for 2 hours, and toluene as an azeotropic solvent was removed over 3 hours. The contents of the flask was cooled to 40 ℃, 1,650 ㎝ derived from an amide bond from the IR ^- it was confirmed that the absorption of near ¹ (C = O) is lost. Polyimide was then added by adding 8.95 g (39.2 mmol) of APAB, 121.6 g of NMP, 6.54 g (30.0 mmol) of PMDA and 4.44 g (10.0 mmol) of 6FDA, followed by stirring at 80°C for 4 hours. -Varnish of polyamic acid polymer was obtained (P-45). The weight average molecular weight (Mw) of the obtained polyimide-polyamic acid polymer was 82,000.

[Examples 48 to 53, Comparative Example 13]

An organic EL substrate as shown in Fig. 1 was produced.

A polyimide precursor varnish (P-1, P-11, P-20, P-22, P-27, P-33, P-45) was used on a mother glass substrate (0.7 mm thick) using a bar coater, After curing, it was applied to a thickness of 10 µm, and then prebaked at 140°C for 60 minutes. Subsequently, the oxygen concentration in the warehouse was adjusted to 10 ppm or less by using a vertical cure (manufactured by Koyo Lindbergh, model name VF-2000B), followed by heat curing treatment at 430°C for 1 hour, and polyimide. A glass substrate on which a resin film was formed was prepared.

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

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

Next, a SiN layer was formed to a thickness of 100 nm on the entire glass substrate on which the scanning signal lines were formed by CVD. (This is referred to as the lower substrate 2a)

Then, an amorphous silicon layer 256 was formed on the lower substrate 2a, dehydrogenation was performed at 430° C. for 1 hour, and the LTPS layer was formed by continuously irradiating an excimer laser.

Subsequently, a photosensitive acrylic resin is coated on the entire surface of the lower substrate 2a by a spin coating method, and exposure and development are performed by a photolithography method to obtain an interlayer insulating film 258 having a plurality of contact holes 257. Formed. A portion of each LTPS 256 was exposed by the contact hole 257.

Next, an ITO film is formed on the entire surface of the lower substrate 2a on which the interlayer insulating film 258 is formed by sputtering, exposure and development are performed by a photolithography method, patterning is performed by an etching method, and each LTPS and The lower electrode 259 was formed to form a pair.

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

Next, after forming the partition wall 251, a hole transport layer 253 and a light emitting layer 254 were formed in each space partitioned by the partition wall 251. In addition, the upper electrode 255 was formed to cover the light emitting layer 254 and the partition wall 251. An organic EL substrate 25 was produced by the above process.

Next, a UV curable resin is coated around the glass substrate, the encapsulation substrate 2b in which the polyimide film of the present embodiment and the SiN layer are formed in this order, and the encapsulation substrate 2b and the organic EL substrate in an argon gas atmosphere. The organic EL element was sealed by bonding. Accordingly, a hollow portion 261 was formed between each organic EL element and the sealing substrate 2b.

The excimer laser (wavelength 308 nm, repetition frequency 300 Hz) is irradiated from the lower substrate 2a side and the encapsulation substrate 2b side of the thus-formed laminate, and peeled with the minimum energy required to peel the entire surface. Was conducted.

About this laminated body, the board|substrate bending after peeling, the lighting test, the cloudiness evaluation of a laminated body, and the presence or absence evaluation were performed. Moreover, it carried out also about the heat cycle test. Table 6 shows the results.

<substrate bending>

◎：No warping

○: There is only a slight bending

△: Rounded by bending

<Lighting test>

○: Lighted

×: Not lit

<Laminated body cloudiness evaluation>

After the layered product was formed, the whole device was designated as a transparent one, △ as slightly cloudy, and Δ as cloudy.

<Heat cycle test>

The external appearance observation was performed after 1000 cycle test of -5 degreeC and 60 degreeC at 30 minutes (bath moving time 1 minute), respectively, using the SPEC manufactured heat cycle tester.

The absence of peeling or swelling was set to ○, and the peeling or swelling was observed to be very partially after the test.

[Examples 54 to 58, Comparative Example 14]

When polyimide precursor varnish (P-1, P-11, P-20, P-22, P-27, P-33, P-45) was used and the above laminate was produced, LTPS was set to IGZO Except for this, a laminate was produced and the test was conducted. Table 7 shows the results.

[Examples 59 to 63, Comparative Example 15]

Polyimide precursor varnish (P-1, P-11, P-20, P) that gives absorbance of 308 nm when YI is 20 or less and film thickness of 0.1 micron is 0.6 or more and 2.0 or less, and gives elongation of 15% or more. -27, P-33, P-45) ash when irradiated with the minimum energy required for laser exfoliation at the time of the laser exfoliation, and the energy with 10 mJ/cm 2 added to the minimum energy (ash content )). ○ that no ash was generated at all, Δ that a little ash was observed at the edge, and Δ that the entire ash was observed were set to ×. Table 8 shows the results.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention.

Industrial availability

The resin film formed from the polyimide precursor of the present invention can be applied to, for example, a semiconductor insulating film, a TFT-LCD insulating film, an electrode protective film, etc., in particular, in the production of flexible displays, substrates for touch panel ITO electrodes, etc. It can be suitably used as a substrate.

Claims (24)

(a1) The following general formula (1):

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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. Structural units L represented by },
The following general formula (2):

{In the formula, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is at least one member selected from the group consisting of the following general formulas (3) and (4).
A polyimide precursor comprising 1/99 ≤ (molar number of structural units L/molar number of structural units M) ≤ 99/1.

{In the formula, R ₄ to R ₉ each independently represent a monovalent organic group having 1 to 20 carbon atoms. Z each independently represents a single bond, a methylene group, an ethylene group, an ether or a ketone. d to i are integers from 0 to 4} According to claim 1,
The polyimide precursor whose n in the said general formula (1) is 0. According to claim 1,
The polyimide precursor whose Y of said general formula (2) is general formula (3). According to claim 1,
The polyimide precursor in which Y of the said general formula (2) is general formula (4). delete delete delete According to claim 1,
X ₁ , X ₂ is pyromellitic acid anhydride (PMDA), 4,4'-oxydiphthalic acid anhydride (ODPA), biphenyltetracarboxylic dianhydride (BPDA), and 4,4'-biphenyl Bis (trimellitic acid monoester acid anhydride) (TAHQ), a polyimide precursor that is a tetravalent organic group derived from at least one member selected from the group consisting of. delete A resin composition comprising the polyimide precursor according to any one of claims 1 to 4 and 8, and (b) an organic solvent. The method of claim 10,
Further, (c) a surfactant, and (d) a resin composition comprising at least one member selected from the group consisting of alkoxysilane compounds. The following general formula (11):

{In the formula, X ₁ and X ₂ represent a tetravalent group having 4 to 32 carbon atoms. 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 member selected from the group consisting of the following general formulas (3) and (4). l and m each independently represent an integer of 1 or more, and satisfies 0.01≦l/(l+m)≦0.99.} A polyimide characterized by having a structural unit.

{In the formula, R ₄ to R ₉ each independently represent a monovalent organic group having 1 to 20 carbon atoms. Z each independently represents a single bond, a methylene group, an ethylene group, an ether or a ketone. d to i are integers from 0 to 4} delete A step of forming a coating film by applying the resin composition according to claim 10 on the surface of the support;
Heating the support and the coating film to imidize 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 of claim 14,
The manufacturing method of the resin film which performs the process of irradiating a laser from the said support side, before the process of peeling the said polyimide resin film from the said support body. delete A step of forming a coating film by applying the resin composition according to claim 10 on the surface of the support;
And heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film. A step of forming a coating film by applying the resin composition according to claim 10 on the surface of the support;
Heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film;
Forming a device or a circuit on the polyimide resin film;
And a step of peeling the polyimide resin film on which the device or circuit is formed from the support. delete delete A laminate comprising the polyimide film layer comprising the polyimide according to claim 12 and a low-temperature polysilicon TFT layer. The following general formula (13):

{In the formula, X ₁ represents a tetravalent group having 4 to 32 carbon atoms. 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 of 0 to 4. A polyimide film layer containing a polyimide represented by },
A flexible display comprising a low-temperature polysilicon TFT layer formed on the polyimide film layer,
The polyimide film layer has the following general formula (11):

{In the formula, X ₁ and X ₂ represent a tetravalent group having 4 to 32 carbon atoms. 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 member selected from the group consisting of the following general formulas (3) and (4). l and m each independently represent an integer of 1 or more and satisfies 0.01 ≤ l / (l + m) ≤ 0.99.) Polyimide having a structural unit represented by}

{In the formula, R ₄ to R ₉ each independently represent a monovalent organic group having 1 to 20 carbon atoms. Z each independently represents a single bond, a methylene group, an ethylene group, an ether or a ketone. d to i are integers from 0 to 4. Flexible display comprising a. delete delete

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