JP2015232055A - Heat-resistant substrate composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition that provides a cured film suitable for a display substrate material having high strength, high heat resistance, moderate linear expansion coefficients and high transparency.SOLUTION: A heat-resistant substrate composition comprises at least one of a polyimide precursor comprising structural units represented by formula (1), formula (2) and formula (3) or an imidized polymer thereof, and organic solvent (in the formulas (1)-(3), Xrepresents a tetravalent group represented by formula (4), Y, Yand Yeach represent divalent groups represented by formulas (5), (6) and (7), and R-Rrepresent hydrogen atoms or the like).

Description

  The present invention relates to a heat-resistant substrate composition, and in particular, has high strength, high heat resistance, an appropriate linear expansion coefficient, and high transparency, and provides a heat-resistant film suitable for a substrate material of an electronic device, particularly a display. It is related with the composition for sex bases.

In recent years, in the field of display devices such as organic electroluminescence (hereinafter also referred to as organic EL) displays and liquid crystal displays, there has been an increasing demand for ultra-thin, lightweight, flexible, and resin materials are attracting attention as a base material. Has been.
However, an active matrix driving panel is used for a high-definition display, and in order to form an active matrix layer including a thin film active element in addition to a matrix-like pixel electrode in the manufacturing process, a temperature of 200 ° C. or higher is required. Not only high temperature processing but also extremely accurate alignment is required. Therefore, when a resin material is used instead of glass as the base material of such a display, it is difficult to satisfy heat resistance and dimensional stability.

  On the other hand, several proposals have been made as resin materials that can avoid problems of heat resistance and dimensional stability. For example, in Patent Document 1, a polyimide film for a display substrate using a polyimide obtained from an alicyclic structure-containing tetracarboxylic dianhydride and various diamines is disclosed, and in Patent Document 2, an alicyclic tetracarboxylic acid having a cyclohexane skeleton is disclosed. A polyimide film for a display substrate using a polyimide obtained from an diamine containing a dianhydride and a sulfone group is disclosed.

However, although high transparency is required for the base material of the display, since the tetracarboxylic dianhydride used in Patent Document 1 contains an aromatic group, it does not contain an aromatic group but consists of an alicyclic hydrocarbon group. Compared to the case of using tetracarboxylic dianhydride, there is a problem that the transparency of the film is lowered due to intramolecular conjugation of polyimide chains and charge transfer interaction.
In addition, the acid dianhydride used in Patent Document 2 is an alicyclic tetracarboxylic dianhydride having a special structure called a cyclohexane skeleton having a cis structure, which is poor in versatility. The manufacturing cost of polyimide is high, and there is room for improvement in that respect.

  For this reason, a material having characteristics necessary for a display substrate that can be manufactured using a highly versatile acid dianhydride has been demanded, but it is a typical alicyclic tetracarboxylic dianhydride used in the synthesis of polyimide. 1,2,3,4-cyclobutanetetracarboxylic dianhydride (hereinafter also referred to as CBDA), the imidation reaction of the polyimide precursor induced thereby is less likely to occur due to the three-dimensional structure. It is pointed out that it is not advantageous to use CBDA as a raw material for polyimide for display substrates because it requires higher temperature to complete the process, which causes coloring of the polyimide film, and can be produced using CBDA. No material suitable for the display substrate has been known.

JP 2008-231327 A Special table 2008-297360 gazette

  The present invention has been made in view of the above circumstances, and uses a highly versatile tetracarboxylic dianhydride to provide a thin film having high strength, high heat resistance, an appropriate linear expansion coefficient, and high transparency. A composition is provided.

｛式（１）〜（３）中、Ｘ^１は、式（４）で表される４価の基を表し

（式（４）中、Ｒ^１〜Ｒ^４は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基又は炭素数１〜６のパーフルオロアルキル基を表す。）、Ｙ^１は、式（５）で表される２価の基を表し

（式（５）中、Ｒ^５〜Ｒ^１２は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表す）、Ｙ^２は、式（６）で表される２価の基を表し

〔式（６）中、Ｒ^１３〜Ｒ^２０は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表す（但し、Ｒ^１３〜Ｒ^２０のうち少なくとも２つはパーフルオロアルキル基を表す。）。〕、Ｙ^３は、式（７）で表される２価の基を表す

（式（７）中、Ｒ^２１〜Ｒ^２４は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表す。）。}
２． 前記Ｙ^１が、式（８）で表される２価の基である１の耐熱性基盤用組成物、

（式（８）中、Ｒ^５〜Ｒ^１２は、前記と同じ意味を表す。）
３． 前記Ｒ^５が、水素原子であり、前記Ｒ^６〜Ｒ^１２が、それぞれ独立して、水素原子又は炭素数１〜６のパーフルオロアルキル基である１又は２の耐熱性基盤用組成物、
４． 前記Ｙ^２が、式（９）で表される２価の基である１〜３のいずれかの耐熱性基盤用組成物、

（式（９）中、Ｒ^１３〜Ｒ^２０は、前記と同じ意味を表す。）
５． 前記Ｒ^１３〜Ｒ^２０が、それぞれ独立して、水素原子又は炭素数１〜６のパーフルオロアルキル基である１〜４のいずれかの耐熱性基盤用組成物、
６． 前記Ｙ^３が、式（１０）で表される２価の基である１〜５のいずれかの耐熱性基盤用組成物、

（式（１０）中、Ｒ^２１〜Ｒ^２４は、前記と同じ意味を表す。）
７． 前記Ｒ^２１〜Ｒ^２４が、それぞれ独立して、水素原子又は炭素数１〜６のパーフルオロアルキル基である１〜６のいずれかの耐熱性基盤用組成物、
８． 前記Ｒ^１〜Ｒ^４が、水素原子、メチル基又はトリフルオロメチル基である１〜７のいずれかの耐熱性基盤用組成物、
９． １〜８のいずれかの耐熱性基盤用組成物を塗布し、加熱することにより得られる薄膜、
１０．９の薄膜からなる基盤材料、
１１．式（１）で表される構造単位、式（２）で表される構造単位及び式（３）で表される構造単位を含むポリイミド前駆体、

｛式（１）〜（３）中、Ｘ^１は、式（４）で表される４価の基を表し

（式（４）中、Ｒ^１〜Ｒ^４は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基又は炭素数１〜６のパーフルオロアルキル基を表す。）、Ｙ^１は、式（５）で表される２価の基を表し

（式（５）中、Ｒ^５〜Ｒ^１２は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表す）、Ｙ^２は、式（６）で表される２価の基を表し

〔式（６）中、Ｒ^１３〜Ｒ^２０は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表す（但し、Ｒ^１３〜Ｒ^２０のうち少なくとも２つはパーフルオロアルキル基を表す。）。〕、Ｙ^３は、式（７）で表される２価の基を表す

（式（７）中、Ｒ^２１〜Ｒ^２４は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表す。）。}
１２．１１のポリイミド前駆体のイミド化重合体
を提供する。 As a result of intensive studies to achieve the above object, the present inventor has obtained 1,2,3,4-cyclobutanetetracarboxylic dianhydride, biphenyldiamine having a perfluoroalkyl group, an imidazole skeleton, and benzene. A composition containing a diamine containing a skeleton, a polyimide precursor derived from phenylenediamine and an imidized polymer thereof, and an organic solvent, with sufficient film strength and appropriate flexibility The present invention has been completed by finding that it has heat resistance necessary for a thin film transistor (TFT) formation process, an appropriate linear expansion coefficient, and high transparency.
That is, the present invention
1. At least one selected from a structural unit represented by formula (1), a structural unit represented by formula (2), a polyimide precursor containing a structural unit represented by formula (3), and an imidized polymer thereof; , A composition for heat-resistant substrate comprising an organic solvent,

{In Formulas (1) to (3), X ¹ represents a tetravalent group represented by Formula (4).

(In Formula (4), R < ¹ > -R < ⁴ > represents a hydrogen atom, a C1-C6 alkyl group, or a C1-C6 perfluoroalkyl group each independently.) Y < ¹ > Represents a divalent group represented by formula (5)

(In Formula (5), R < ⁵ > -R < ¹² > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. And Y ² represents a divalent group represented by the formula (6).

[In Formula (6), R < ¹³ > -R < ²⁰ > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. Represents a group (provided that at least two of R ^{13 to} R ²⁰ represent a perfluoroalkyl group). Y ³ represents a divalent group represented by the formula (7).

(In Formula (7), R < ²¹ > -R < ²⁴ > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. Represents a group). }
2. 1 for a heat-resistant substrate, wherein Y ¹ is a divalent group represented by formula (8):

(In formula (8), R ^{5 to} R ¹² represent the same meaning as described above.)
3. 1 or 2 heat-resistant base composition, wherein R ⁵ is a hydrogen atom, and R ^{6 to} R ¹² are each independently a hydrogen atom or a C 1-6 perfluoroalkyl group,
4). The heat-resistant base composition according to any one of 1 to 3, wherein Y ² is a divalent group represented by formula (9):

(In formula (9), R ^{13 to} R ²⁰ represent the same meaning as described above.)
5). R ^{13 to} R ²⁰ are each independently a heat resistant base composition according to any one of 1 to 4 which is a hydrogen atom or a C 1-6 perfluoroalkyl group,
6). The composition for heat-resistant base according to any one of 1 to 5, wherein Y ³ is a divalent group represented by formula (10):

(In formula (10), R ^{21 to} R ²⁴ represent the same meaning as described above.)
7). Each of R ^{21 to} R ²⁴ is independently a hydrogen atom or a heat-resistant base composition according to any one of 1 to 6 which is a C 1-6 perfluoroalkyl group,
8). The heat-resistant base composition according to any one of 1 to 7, wherein R ^{1 to} R ⁴ are a hydrogen atom, a methyl group, or a trifluoromethyl group;
9. A thin film obtained by applying and heating the heat-resistant base composition of any one of 1 to 8,
A base material consisting of a thin film of 10.9,
11. A polyimide precursor comprising a structural unit represented by formula (1), a structural unit represented by formula (2) and a structural unit represented by formula (3);

{In Formulas (1) to (3), X ¹ represents a tetravalent group represented by Formula (4).

(In Formula (4), R < ¹ > -R < ⁴ > represents a hydrogen atom, a C1-C6 alkyl group, or a C1-C6 perfluoroalkyl group each independently.) Y < ¹ > Represents a divalent group represented by formula (5)

(In Formula (5), R < ⁵ > -R < ¹² > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. And Y ² represents a divalent group represented by the formula (6).

[In Formula (6), R < ¹³ > -R < ²⁰ > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. Represents a group (provided that at least two of R ^{13 to} R ²⁰ represent a perfluoroalkyl group). Y ³ represents a divalent group represented by the formula (7).

(In Formula (7), R < ²¹ > -R < ²⁴ > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. Represents a group). }
An imidized polymer of 12.11 polyimide precursor is provided.

  The heat-resistant composition of the present invention is a thin film having both high strength, high heat resistance, an appropriate linear expansion coefficient and high transparency by forming a film by a wet process such as a spin coat method and heating, particularly in recent years. In order to provide a thin film that satisfies the requirements in the display field, it can contribute to the development of device fields such as organic EL displays and liquid crystal displays.

Hereinafter, the present invention will be described in detail.
The composition for heat-resistant substrates of the present invention comprises a structural unit represented by the formula (1), a structural unit represented by the formula (2) and a polyimide precursor containing the structural unit represented by the formula (3) and It contains at least one selected from imidized polymers.

In the present invention, the imidized polymer means that an amide group and a carboxylic acid group in the polyimide precursor react to form an imide group, and at least one selected from formulas (11) to (19). Including species.

In formulas (1) to (19), X ¹ represents a tetravalent group represented by formula (4).

In formula (4), R < ¹ > -R < ⁴ > represents a hydrogen atom, a C1-C6 alkyl group, or a C1-C6 perfluoroalkyl group each independently.
Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, 1-methyl- Examples include n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, n-hexyl group and the like.
As a C1-C6 perfluoroalkyl group, the group by which all the hydrogen atoms in the said C1-C6 alkyl group were substituted by the fluorine atom is mentioned.
Specific examples thereof include trifluoromethyl, pentafluoroethyl, heptafluoro-n-propyl, heptafluoro-i-propyl, nonafluoro-n-butyl, nonafluoro-i-butyl, nonafluoro-s-butyl, nonafluoro-t-butyl. Groups and the like.
Among these, in consideration of the balance between transparency and heat resistance of the obtained cured film, R ^{1 to} R ⁴ are preferably a hydrogen atom, a methyl group, or a trifluoromethyl group, and are all hydrogen atoms. More preferred.

式（５）中、Ｒ^５〜Ｒ^１２は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表す。
炭素数６〜１４の芳香族基としては、フェニル、１−ナフチル、２−ナフチル、１−アントリル、２−アントリル、９−アントリル、１−フェナントリル、２−フェナントリル、３−フェナントリル、４−フェナントリル、９−フェナントリル基等が挙げられる。
炭素数１〜６のアルキル基及び炭素数１〜６のパーフルオロアルキル基としては、上記と同様のものが挙げられる。 In formulas (1) and (11) to (13), Y ¹ represents a divalent group represented by formula (5).

In formula (5), R ^{5 to} R ¹² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a perfluoroalkyl group having 1 to 6 carbon atoms, or an aromatic group having 6 to 14 carbon atoms. Represents.
Examples of the aromatic group having 6 to 14 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, A 9-phenanthryl group and the like can be mentioned.
Examples of the alkyl group having 1 to 6 carbon atoms and the perfluoroalkyl group having 1 to 6 carbon atoms are the same as those described above.

式（８）中、Ｒ^５〜Ｒ^１２は、上記と同じ意味を示す。
特に、得られる硬化膜の透明性と耐熱性のバランスを考慮すると、式（５）及び（８）中、Ｒ^５が、水素原子又はメチル基であり、Ｒ^６〜Ｒ^１２が、水素原子又は炭素数１〜６のパーフルオロアルキル基であることが好ましく、Ｒ^５〜Ｒ^１２が、全て水素原子であることがより好ましい。 Examples of the divalent group represented by the formula (5) include a divalent group represented by the formula (8).

In formula (8), R ^{5 to} R ¹² have the same meaning as described above.
In particular, considering the balance between transparency and heat resistance of the cured film obtained, in formulas (5) and (8), R ⁵ is a hydrogen atom or a methyl group, and R ^{6 to} R ¹² are a hydrogen atom or A perfluoroalkyl group having 1 to 6 carbon atoms is preferred, and R ^{5 to} R ¹² are all preferably hydrogen atoms.

式（６）中、Ｒ^１３〜Ｒ^２０は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表すが、Ｒ^１３〜Ｒ^２０のうち少なくとも２つはパーフルオロアルキル基である。
炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基及び炭素数６〜１４の芳香族基としては、上記と同様のものが挙げられる。 In Formula (2) and Formulas (14) to (16), Y ² represents a divalent group represented by Formula (6).

In formula (6), R ^{13 to} R ²⁰ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a perfluoroalkyl group having 1 to 6 carbon atoms, or an aromatic group having 6 to 14 carbon atoms. In the formula, at least two of R ^{13 to} R ²⁰ are perfluoroalkyl groups.
Examples of the alkyl group having 1 to 6 carbon atoms, the perfluoroalkyl group having 1 to 6 carbon atoms, and the aromatic group having 6 to 14 carbon atoms are the same as those described above.

式（９）中、Ｒ^１３〜Ｒ^２０は、上記と同じ意味を示す。
特に、得られる硬化膜の耐熱性のバランスを考慮すると、式（６）及び（９）中、Ｒ^１３〜Ｒ^２０の２〜４つが炭素数１〜６のパーフルオロアルキル基であり、それ以外は水素原子であることが好ましく、Ｒ^１３〜Ｒ^２０の２〜４つが炭素数１〜４のパーフルオロアルキル基であり、それ以外は水素原子であることがより好ましい。 Examples of the divalent group represented by the formula (6) include a divalent group represented by the formula (9).

In formula (9), R ^{13 to} R ²⁰ have the same meaning as described above.
In particular, considering the balance of heat resistance of the obtained cured film, in formulas (6) and (9), 2 to 4 of R ^{13 to} R ²⁰ are perfluoroalkyl groups having 1 to 6 carbon atoms. Is preferably a hydrogen atom, 2 to 4 of R ^{13 to} R ²⁰ are perfluoroalkyl groups having 1 to 4 carbon atoms, and the others are more preferably hydrogen atoms.

式（７）中、Ｒ^２１〜Ｒ^２４は、それぞれ独立して、水素原子、炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基又は炭素数６〜１４の芳香族基を表す。
炭素数１〜６のアルキル基、炭素数１〜６のパーフルオロアルキル基及び炭素数６〜１４の芳香族基としては、上記と同様のものが挙げられる。 In formulas (3) and (17) to (19), Y ³ represents a divalent group represented by formula (7).

In formula (7), R ^{21 to} R ²⁴ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a perfluoroalkyl group having 1 to 6 carbon atoms, or an aromatic group having 6 to 14 carbon atoms. Represents.
Examples of the alkyl group having 1 to 6 carbon atoms, the perfluoroalkyl group having 1 to 6 carbon atoms, and the aromatic group having 6 to 14 carbon atoms are the same as those described above.

式（１０）中、Ｒ^２１〜Ｒ^２４は、上記と同じ意味を示す。
特に、得られる硬化膜の耐熱性のバランスを考慮すると、式（７）及び（１０）中、Ｒ^２１〜Ｒ^２４は、水素原子又は炭素数１〜６のパーフルオロアルキル基であることが好ましく、水素原子又はトリフルオロメチルであることがより好ましく、全て水素原子であることがより一層好ましい。 Examples of the divalent group represented by the formula (7) include a divalent group represented by the formula (10).

In formula (10), R ^{21 to} R ²⁴ have the same meaning as described above.
In particular, in consideration of the heat resistance balance of the obtained cured film, in formulas (7) and (10), R ^{21 to} R ²⁴ are preferably a hydrogen atom or a C 1-6 perfluoroalkyl group. More preferably a hydrogen atom or trifluoromethyl, and even more preferably all hydrogen atoms.

The combination of X ¹ and Y ^{1 to} Y ³ is such that R ^{1 to} R ⁴ are a hydrogen atom, a methyl group or a trifluoromethyl group, a tetravalent group represented by the formula (4), and R ⁵ is a hydrogen atom or A divalent group represented by the formula (5) which is a methyl group and R ^{6 to} R ¹² are a hydrogen atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and 2 to 4 of R ^{13 to} R ²⁰ A divalent group represented by the formula (6) which is a perfluoroalkyl group having 1 to 6 carbon atoms and is a hydrogen atom, and R ^{21 to} R ²⁴ are a hydrogen atom or a perfluorocarbon group having 1 to 6 carbon atoms. A divalent group represented by formula (7) which is a fluoroalkyl group is preferred, and a tetravalent group represented by formula (4) wherein R ^{1 to} R ⁴ are a hydrogen atom, a methyl group or a trifluoromethyl group. When, ^{R 5} is a hydrogen atom or a methyl ^group, R 6 ^{to R 12} is C1-6 hydrogen or C Divalent group and represented by the formula (8) is a perfluoroalkyl group, one to four of R ¹³ to R ²⁰ is a perfluoroalkyl group having 1 to 6 carbon atoms, is a hydrogen atom otherwise A divalent group represented by the formula (9) and a divalent group represented by the formula (10) in which R ^{21 to} R ²⁴ are a hydrogen atom or a C 1-6 perfluoroalkyl group are more preferable. A tetravalent group represented by the formula (4) in which R ^{1 to} R ⁴ are all hydrogen atoms, and a divalent group represented by the formula (8) in which R ^{5 to} R ¹² are all hydrogen atoms; 2 to 4 of R ^{13 to} R ²⁰ are perfluoroalkyl groups having 1 to 4 carbon atoms, and other than that, a divalent group represented by formula (9) which is a hydrogen atom, and R ^{21 to} R ²⁴ A divalent group represented by the formula (10) in which all are hydrogen atoms is even more preferable.

Although the example of the bivalent group represented by Formula (9) below is shown, it is not necessarily limited to these.

  The polymerization average molecular weight of the polyimide precursor and imidized polymer is preferably 3,000 to 150,000 in terms of polystyrene. If the weight average molecular weight is less than 3,000, the resulting thin film may become brittle, and if it exceeds 150,000, the viscosity of the composition (varnish) may become too high, resulting in difficulty in handling. It is because it may become.

The number n ^{1 of} structural units represented by the formula (1) in the polyimide precursor, the number n ^{2 of} structural units represented by the formula (2), and the number n ^{3 of} structural units represented by the formula (3) are: , N ² / (n ¹ + n ³ ) = 70/30 to 99/1 is preferable, and 75/25 to 95/5 is more preferable.
Further, ^{n 1} and ^{n 3 are,} it is preferable to satisfy ^{n 1 / n 3 = 10 /} 90~90 / 10, more preferably satisfies the ^{n 1 / n 3 = 40 /} 60~60 / 40.

The solvent used in preparing the composition of the present invention is not particularly limited as long as it can dissolve the polyimide precursor and the imidized polymer satisfactorily.
Examples of such solvents include N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, dimethyl sulfoxide, and γ-butyrolactone. 1,3-dimethyl-2-imidazolidinone, 1,2-dimethoxyethane-bis (2-methoxyethyl) ether, tetrahydrofuran, 1,4-dioxane, picoline, pyridine, acetone, chloroform, toluene, xylene, etc. Examples include aprotic solvents, and protic solvents such as phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, p-chlorophenol, and the like. 5 to 100% by mass with respect to the total solvent Can. These solvents may be used alone or in combination of two or more.

  In addition, cyclohexanol, ethylene glycol, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol are used for the purpose of improving the wettability with respect to the substrate, adjusting the surface tension of the solvent, adjusting the polarity, adjusting the boiling point, and the like. Solvents that cannot dissolve polyimide or imidized polymers such as ethylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, propylene glycol, and hexylene glycol. The polyimide precursor and imidized polymer may be added to the composition as long as they do not precipitate. These solvents can be used alone or in combination of two or more.

  The composition of this invention can be manufactured by melt | dissolving the said polyimide precursor and / or a polyimide polymer in the above-mentioned solvent. Moreover, the reaction liquid obtained by reaction of the below-mentioned polyimide precursor can also be used as the composition of the present invention as it is or after being concentrated or diluted.

  The concentration of the polyimide precursor and imidized polymer in the composition of the present invention is usually 5 to 40% by mass with respect to the total mass (total mass) of the solvent used, but the storage stability of the composition is taken into consideration. Then, it is preferably 8 to 30% by mass, and more preferably 10 to 20% by mass.

The composition of the present invention may contain a crosslinking agent (hereinafter also referred to as a crosslinkable compound) within a range that does not significantly impair the heat resistance, transparency, linear expansion coefficient and flexibility of the thin film obtained.
The crosslinkable compound is a step of converting a coating film obtained using the composition of the present invention into a cured film, and a group capable of reacting with an organic group contained in at least one of a polyimide precursor and an imidized polymer. Although it will not specifically limit if it is a compound having, for example, a compound containing two or more epoxy groups or a group in which a hydrogen atom of an amino group is substituted with a methylol group, an alkoxymethyl group or both , Melamine derivatives, benzoguanamine derivatives or glycoluril. The melamine derivative and benzoguanamine derivative may be a dimer or a trimer, and may be a mixture arbitrarily selected from a monomer, a dimer and a trimer. These crosslinking agents can be used alone or in combination of two or more.

Although the specific example of a crosslinkable compound is given to the following, it is not limited to this.
Examples of the compound containing two or more epoxy groups include cyclohexene structures such as Epolide GT-401, Epolide GT-403, Epolide GT-301, Epolide GT-302, Celoxide 2021, Celoxide 3000 (manufactured by Daicel Corporation). Epicoat 1001, Epicoat 1002, Epicoat 1003, Epicoat 1004, Epicoat 1007, Epicoat 1009, Epicoat 1010, Epicoat 828 (above, Japan Epoxy Resin Co., Ltd. (currently Mitsubishi Chemical Corporation, presently jER) Bisphenol A type epoxy compounds such as Epicote 807 (manufactured by Japan Epoxy Resin Co., Ltd. (currently Mitsubishi Chemical Corporation, presently jER (registered trademark) series))) Poxy compounds; Epicoat 152, Epicoat 154 (above, Japan Epoxy Resin Co., Ltd. (currently Mitsubishi Chemical Corporation, presently jER (registered trademark) series)), EPPN201, EPPN202 (above, Nippon Kayaku Co., Ltd.) Phenol novolac epoxy compounds such as: ECON-102, ECON-103S, ECON-104S, ECON-1020, ECON-1025, ECON-1027 (above, Nippon Kayaku Co., Ltd.), Epicoat 180S75 (Japan Epoxy Resin ( Cresol novolak type epoxy compounds such as (manufactured by Mitsubishi Chemical Corporation, currently jER (registered trademark) series); naphthalene type epoxy compounds such as V8000-C7 (manufactured by DIC Corporation); Denacol EX-252 ( Nagase ChemteX Corporation), CY175, C Y177, CY179, Araldite CY-182, Araldite CY-192, Araldite CY-184 (above, manufactured by BASF), Epicron 200, Epicron 400 (above, manufactured by DIC Corporation), Epicoat 871, Epicoat 872 (above, Japan) Cycloaliphatic epoxy compounds such as Epoxy Resin Co., Ltd. (currently Mitsubishi Chemical Co., Ltd., present jER (registered trademark) series), ED-5661, ED-5661 (above, Celanese Coating Co., Ltd.); Denacol EX-611, Denacol EX-612, Denacol EX-614, Denacol EX-622, Denacol EX-411, Denacol EX-512, Denacol EX-522, Denacol EX-421, Denacol EX-313, Denacol EX-314, Denacor EX-31 (Above, manufactured by Nagase ChemteX Corporation) aliphatic polyglycidyl ether compounds, and the like.

  As the melamine derivative, benzoguanamine derivative, or glycoluril having a group in which the hydrogen atom of the amino group is substituted with a methylol group, an alkoxymethyl group, or both, an average of 3.7 methoxymethyl groups are substituted per triazine ring. MX-750, MW-30 substituted with an average of 5.8 methoxymethyl groups per triazine ring (above, manufactured by Sanwa Chemical Co., Ltd.); Cymel 300, Cymel 301, Cymel 303, Cymel 350 Methoxymethylated melamine such as Cymel 370, Cymel 771, Cymel 325, Cymel 327, Cymel 703, Cymel 712 and the like; Cymel 235, Cymel 236, Cymel 238, Cymel 212, Cymel 253, Cymel 254 and the like Mela Butylmethylated melamines such as Cymel 506 and Cymel 508; carboxyl group-containing methoxymethylated isobutoxymethylated melamines such as Cymel 1141; methoxymethylated ethoxymethylated benzoguanamines such as Cymel 1123; Methoxymethylated butoxymethylated benzoguanamine; butoxymethylated benzoguanamine such as Cymel 1128; carboxyl-containing methoxymethylated ethoxymethylated benzoguanamine such as Cymel 1125-80; butoxymethylated glycoluril such as Cymel 1170; Cymel 1172 Such as methylolated glycoluril (manufactured by Mitsui Cyanamid Co., Ltd. (currently Cytec Industries)).

The polyimide precursor contained in the composition of the present invention is also an object of the present invention, for example, tetracarboxylic dianhydride represented by the formula (20) and three diamines, that is, represented by the formula (21). It can be obtained by reacting the diamine represented by formula (22) and the diamine represented by formula (23).

In formula (20) to formula (23), R ^{1 to} R ²⁴ have the same meaning as described above.
In the above reaction, the diamine substance amount M ¹ represented by the formula (21), the diamine substance amount M ² represented by the formula (22), and the diamine substance amount M ³ represented by the formula (23) are: It is preferable to satisfy M ² / (M ¹ + M ³ ) = 70/30 to 99/1, and it is more preferable to satisfy 75/25 to 95/5.
Further, ^{M 1} and ^{M 3,} it is preferable to satisfy the ^{M 1 / M 3 = 10 /} 90~90 / 10, more preferably satisfies the ^{M 1 / M 3 = 40 /} 60~60 / 40.

  In the above reaction, the charge ratio of the carboxylic dianhydride component represented by formula (20) and the total diamine (diamine represented by formulas (21) to (23)) is 1 mol of carboxylic dianhydride. Usually, the total diamine is about 0.8 to 1.2 mol, preferably about 0.95 to 1.05 mol.

The solvent used for the reaction of the polyimide precursor is not particularly limited as long as it can dissolve the raw material compound and does not inhibit the reaction.
Specific examples thereof include N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, dimethyl sulfoxide, γ-butyrolactone, 1, Aprotic such as 3-dimethyl-2-imidazolidinone, 1,2-dimethoxyethane-bis (2-methoxyethyl) ether, tetrahydrofuran, 1,4-dioxane, picoline, pyridine, acetone, chloroform, toluene, xylene Examples include solvents and protic solvents such as phenol, o-cresol, m-cresol, p-cresol, o-chlorophenol, m-chlorophenol, and p-chlorophenol. These solvents may be used alone or in combination of two or more.

  What is necessary is just to set reaction temperature suitably in the range from the melting | fusing point of the solvent to be used to the boiling point of a solvent, and is about -20-100 degreeC normally, Preferably it is about 15-80 degreeC. The polymerization reaction time is usually about 1 to 72 hours.

On the other hand, the imidized polymer contained in the composition of the present invention is also an object of the present invention, and can be obtained, for example, by dehydrating and ring-closing (imidizing) the polyimide precursor. As a method of dehydrating and cyclizing, either dehydration cyclization by heating (thermal imidization) or dehydration cyclization by a catalyst can be adopted.
The heating temperature of dehydration and cyclization by heating is not particularly limited as long as the cyclization reaction proceeds, but is usually 100 to 450 ° C, preferably 100 to 420 ° C.
Further, the dehydration ring closure using a catalyst is performed in the presence of a base and an acid, for example. As the temperature for dehydration ring closure by the catalyst, any temperature can be selected as long as the reaction proceeds.

  As the tetracarboxylic dianhydride and diamine used in the above reaction, commercially available products may be used, or those synthesized by a known method may be used.

A thin film suitable for the base material can be formed on the substrate by applying the composition (varnish) described above onto the substrate and evaporating the solvent.
The coating method of the varnish is not particularly limited, and the cast coating method, spin coating method, blade coating method, dip coating method, roll coating method, bar coating method, die coating method, ink jet method, printing method (letter plate, Intaglio, lithographic, screen printing, etc.).
Moreover, as a base material for apply | coating a varnish, plastics (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetylcellulose, ABS, AS, norbornene resin etc.), metal, wood, Examples include paper, glass, and slate.

The solvent of the varnish may be evaporated in an appropriate atmosphere, that is, in an inert gas such as air, nitrogen, or in a vacuum using a hot plate or an oven, for example. Thereby, a thin film having a uniform film formation surface can be obtained.
A calcination temperature is 100-450 degreeC normally, Preferably it is 100-420 degreeC. In this case, two or more stages of temperature changes may be applied for the purpose of developing higher uniform film forming properties or allowing the reaction to proceed on the substrate.

Although the film thickness of a cured film is not specifically limited, When using especially as base films (base material), such as a flexible display, Preferably it is 1-50 micrometers, More preferably, it is 5-40 micrometers.
Methods for changing the film thickness include methods such as changing the solid content concentration in the varnish and changing the amount of the solution on the substrate during application.

  The cured film obtained by the method described above has moderate flexibility, excellent heat resistance, moderate linear expansion coefficient, and high transparency, so these characteristics such as liquid crystal display, organic EL lighting, electronic paper, etc. It is expected to be used as a base material in the field of devices that need to be used.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to the following Example.

[1] Abbreviations used in the examples PDA: p-phenylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.)
APAB: 2- (3-aminophenyl) -5-aminobenzimidazole (manufactured by Changzhou Sunlight Pharmaceutical Co., Ltd.) (formula (24))
TFMB: 2,2′-bis (trifluoromethyl) benzidine (manufactured by Tokyo Chemical Industry Co., Ltd.) (formula (25))
BAPPS: Bis [4- (3-aminophenoxy) phenyl] sulfone (manufactured by Tokyo Chemical Industry Co., Ltd.) (formula (26))
BAPS: bis (3-aminophenyl) sulfone (manufactured by Tokyo Chemical Industry Co., Ltd.) (formula (27))

[2] Measurement of polymer weight average molecular weight (hereinafter also referred to as Mw) and molecular weight distribution The gel permeation chromatography (GPC) apparatus used for the measurement of polymer Mw and molecular weight distribution and the conditions thereof are as follows. In addition, Mw was made into the polystyrene conversion value.
GPC: ChromNav, manufactured by JASCO Column: manufactured by Showa Denko KK Shodex [registered trademark] SB803HQ and SB804HQ
Column temperature: 40 ° C
Solvent: N, N-dimethylformamide (0.9 mL / min)
Detector: RI

[3] Synthesis of polyimide precursor acid and production of varnish [Example 1]
TFMB 16 g (0.005 mol), APAB 1.4 g (0.0006 mol), PDA 0.63 g (0.0006 mol) were dissolved in 170 g, and CBDA (Tokyo Chemical Industry Co., Ltd.) 12 g (0.061 The polymer was obtained by reacting at 23 ° C. for 24 hours under a nitrogen atmosphere (Mw 38,700 molecular weight distribution 2.1).
The obtained polymer solution was directly used as a varnish of Example 1 for production of a cured film described later (solid content: 15%).

[Comparative Example 1]
4.13 g (0.0095 mol) of BAPPS was dissolved in 14.0 g of NMP, and 1.87 g (0.0095 mol) of CBDA was added, followed by reaction at 23 ° C. for 24 hours in a nitrogen atmosphere to obtain a polymer. (Mw 19,800 molecular weight distribution 2.1).
The obtained polymer solution was directly used as a varnish of Comparative Example 1 for the production of a cured film described later (solid content 30%).

[Comparative Example 2]
3.35 g (0.013 mol) of BAPS was dissolved in 14.0 g of NMP, and 2.65 g (0.014 mol) of CBDA was added, followed by reaction at 23 ° C. for 24 hours in a nitrogen atmosphere to obtain a polymer. (Mw 13,600 molecular weight distribution 3.1)
The obtained polymer solution was directly used as a varnish of Comparative Example 2 for production of a cured film described later (solid content 30%).

[4] Preparation of cured film and evaluation thereof <Preparation of cured film and evaluation of film thickness>
The varnishes produced in Example 1 and Comparative Examples 1 and 2 were coated on a glass substrate with a bar coater, and under reduced pressure, 110 ° C. for 10 minutes, 230 ° C. for 30 minutes, 300 ° C. for 30 minutes, 350 ° C. for 120 minutes. A cured film was obtained by sequential heating for minutes.
The film thickness of the obtained cured film was measured using a contact-type film thickness measuring device (Dektak 3ST manufactured by ULVAC, Inc.).

<Evaluation of self-supporting>
The glass substrate with the cured film formed on the surface was left in pure water at 70 ° C. to peel the cured film. The self-supporting property was evaluated by a method of bending the peeled cured film.

<Heat resistance measurement>
A small piece having a weight of about 5 mg was cut out from the peeled cured film, this small piece was heated (heated from 50 ° C. to 500 ° C. at a rate of 5 ° C. per minute), and its 5% mass reduction was measured to evaluate the heat resistance. . For the evaluation, TG / DTA-2000SA (manufactured by Bruker AXS Co., Ltd.) was used.

<Transmittance measurement>
The transmittance of the cured film with the glass substrate prepared above was measured using a self-recording spectrophotometer UV-3100PC manufactured by Shimadzu Corporation.

<Linear expansion coefficient>
A 20 mm × 5 mm strip was cut out from the peeled cured film, and this strip was heated from 50 ° C. to 150 ° C. at 5 ° C./min using TMA-4000SA (manufactured by Bruker AXS Co., Ltd.) After cooling, it was heated again at 50 ° C. to 400 ° C. to measure the linear expansion coefficient. In addition, since the cured film of Comparative Example 2 did not have sufficient self-supporting property, the linear expansion coefficient could not be measured.

※１ ○：自己支持性あり。９０度に曲げても割れない。
△：自己支持性あり。但し衝撃で割れる。
×：自己支持性なし。 The results of the evaluation are shown in Table 1. The transmittance is a value at a wavelength of 400 nm.
As shown in Table 1, the cured film obtained from the varnish of Example 1 was not only low in linear expansion coefficient but also superior to those obtained from the varnishes produced in Comparative Examples 1 and 2. The result of having transparency, self-supporting property and heat resistance was obtained.

* 1 ○: Self-supporting. Even if it is bent at 90 degrees, it does not break.
Δ: Self-supporting. However, it breaks on impact.
X: No self-supporting property.

Claims (12)

At least one selected from a structural unit represented by formula (1), a structural unit represented by formula (2), a polyimide precursor containing a structural unit represented by formula (3), and an imidized polymer thereof; And a heat-resistant substrate composition comprising an organic solvent.

{In Formulas (1) to (3), X ¹ represents a tetravalent group represented by Formula (4).

(In Formula (4), R < ¹ > -R < ⁴ > represents a hydrogen atom, a C1-C6 alkyl group, or a C1-C6 perfluoroalkyl group each independently.) Y < ¹ > Represents a divalent group represented by formula (5)

(In Formula (5), R < ⁵ > -R < ¹² > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. And Y ² represents a divalent group represented by the formula (6).

[In Formula (6), R < ¹³ > -R < ²⁰ > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. Represents a group (provided that at least two of R ^{13 to} R ²⁰ represent a perfluoroalkyl group). Y ³ represents a divalent group represented by the formula (7).

(In Formula (7), R < ²¹ > -R < ²⁴ > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. Represents a group). } The heat-resistant base composition according to claim 1, wherein Y ¹ is a divalent group represented by formula (8).

(In formula (8), R ^{5 to} R ¹² represent the same meaning as described above.) The R ⁵ is a hydrogen atom, and the R ^{6 to} R ¹² are each independently a hydrogen atom or a C 1-6 perfluoroalkyl group. Composition. Wherein Y ² is, heat resistance based composition according to claim 1 is a divalent group represented by the formula (9).

(In formula (9), R ^{13 to} R ²⁰ represent the same meaning as described above.) Said R < ¹³ > -R < ²⁰ > is a hydrogen atom or a C1-C6 perfluoroalkyl group each independently, The composition for heat resistant base | substrates of any one of Claims 1-4. Wherein Y ³ is, heat resistance based composition according to claim 1 is a divalent group represented by the formula (10).

(In formula (10), R ^{21 to} R ²⁴ represent the same meaning as described above.) Wherein R ²¹ to R ²⁴ are each independently of the heat resistance based composition according to any one of claims 1 to 6 is a hydrogen atom or a perfluoroalkyl group having 1 to 6 carbon atoms. Said R < ¹ > -R < ⁴ > is a hydrogen atom, a methyl group, or a trifluoromethyl group, The composition for heat resistant base | substrates of any one of Claims 1-7.   The thin film obtained by apply | coating the composition for heat resistant base | substrates of any one of Claims 1-8, and heating.   A base material comprising the thin film according to claim 9. The polyimide precursor containing the structural unit represented by Formula (1), the structural unit represented by Formula (2), and the structural unit represented by Formula (3).

{In Formulas (1) to (3), X ¹ represents a tetravalent group represented by Formula (4).

(In Formula (4), R < ¹ > -R < ⁴ > represents a hydrogen atom, a C1-C6 alkyl group, or a C1-C6 perfluoroalkyl group each independently.) Y < ¹ > Represents a divalent group represented by formula (5)

(In Formula (5), R < ⁵ > -R < ¹² > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. And Y ² represents a divalent group represented by the formula (6).

[In Formula (6), R < ¹³ > -R < ²⁰ > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. Represents a group (provided that at least two of R ^{13 to} R ²⁰ represent a perfluoroalkyl group). Y ³ represents a divalent group represented by the formula (7).

(In Formula (7), R < ²¹ > -R < ²⁴ > is respectively independently a hydrogen atom, a C1-C6 alkyl group, a C1-C6 perfluoroalkyl group, or a C6-C14 aromatic. Represents a group). }   The imidized polymer of the polyimide precursor of Claim 11.