JP6665862B2 - Polyimide precursor, polyimide having crosslinked structure and method for producing the same - Google Patents

Description

  The present invention relates to a polyimide precursor capable of easily producing a polyimide having a high crosslinking density, a polyimide having a crosslinked structure having excellent heat resistance and dimensional stability at high temperatures, and a method for producing the same. Further, another aspect of the present invention relates to a polyimide precursor capable of easily producing a high heat-resistant polyimide, and a method for producing the same.

  Polyimide is superior to other engineering plastics in terms of mechanical properties, electrical properties, etc., in addition to excellent heat resistance, and its high reliability obtained in space and aerospace applications makes it applicable to industrial applications. It is widely used as a heat-resistant insulation material for consumer use. However, in recent years, the downsizing and weight reduction of electronic devices, multifunctionality and high performance have been remarkably progressed, and excellent heat resistance and dimensional stability exceeding conventional polyimide materials have been required. Until now, in the research and development of polyimides, various characteristics have been improved by combining various diamines and acid anhydrides.

  It has been studied that heat resistance and chemical resistance such as decomposition temperature and glass transition temperature of a resin can be improved by introducing a crosslinked structure into the resin (Non-Patent Document 1). Patent Literature 1 discloses that a polycarboxylic acid is produced by reacting a tetracarboxylic dianhydride with a triamine in a molar ratio of 1/2 to less than 3/2, and this is imidized to produce a hyperbranched polyimide. Furthermore, a multi-branched polyimide for promoting electroless plating, in which an electroless plating catalyst precursor substance is adsorbed to the amide group, is described. Patent Literature 2 describes a terminal-modified multi-branched polyimide obtained from tetracarboxylic dianhydride, triamine, and a terminal component.

  In addition, since many polyimides are hardly soluble or insoluble in organic solvents, solutions in which a polyamic acid that is soluble in an organic solvent is dissolved in a solvent have been used in various applications. A polyamic acid solution is a polymer solution having a high degree of polymerization.When a polyimide coating is obtained from this polymer solution, the polymer solution is generally coated on a substrate such as copper or glass, and heated. Then, removal of the solvent and imidization proceed to obtain a polyimide coating film.

  However, when coating a polymer solution having a high degree of polymerization, there is a problem that the solid content concentration must be reduced in order to obtain a coatable viscosity. In addition, if the solid content is increased to increase the productivity, the viscosity of the solution becomes high, so that there is a problem that the coating cannot be performed, and even if the coating can be performed, good mechanical and thermal properties are obtained. There was a problem that it was not possible to obtain a coating film or film having the following. Further, the polymer solution is hard to withstand storage for a long period of time, and it is extremely difficult to store the polymer solution for a long period of time while maintaining its degree of polymerization. As a method for solving this problem, Patent Literature 3 reports that if a specific monomer is combined, a thermoplastic polyimide coating film can be obtained directly from a solution of the monomer, even if it is not a polymer.

JP 2008-50694 A WO2008 / 013210 JP-A-11-333376

Katrien Vanhercka et al., Progress in PolymerScience 38 (2013) 874-896 Yoshiaki Echigo et al., Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 37, 11-14 (1999)

  Polyimide is generally synthesized by synthesizing a polyamic acid, which is a precursor thereof, and then performing a ring closing reaction of an imide ring. Also in Patent Documents 1 and 2 and Non-patent Document 1, polyimide is synthesized via polyamic acid. However, when a cross-linked structure is introduced, it is easily gelled, so that it is limited to a low-concentration polyamic acid solution, and thus there is a problem that various restrictions are imposed on actual use.

  One embodiment of the present invention has been made to solve these problems, and a polyimide precursor capable of easily producing a polyimide having a suitably high crosslink density and a heat resistant, crosslinked polyimide having excellent dimensional stability at high temperatures. , And a method of manufacturing the same.

  A different aspect of the present invention provides a polyimide precursor capable of easily producing a polyimide having a suitably high cross-linking density, a cross-linked polyimide excellent in heat resistance, dimensional stability at high temperatures, and excellent bending resistance, and a method for producing the same. The purpose is to:

  Patent Document 3 reports that a thermoplastic polyimide coating film can be obtained by a combination of specific monomers. Among polyimides, 3,3 ′, 4,4′-biphenyltetra is excellent in heat resistance. It has been reported that a combination of carboxylic acid (s-BPTA) and a diamine having an aromatic ring with a para-position bond (for example, paraphenylenediamine (PPD)) has poor solubility, and a polyimide precursor solution cannot be obtained. (Non-Patent Document 2). For this reason, a method of directly obtaining a polyimide coating film from a monomer solution has not been known for a highly heat-resistant polyimide using s-BPTA.

  Therefore, a further different aspect of the present invention aims to provide a polyimide precursor which mainly comprises a combination of s-BPTA or a derivative thereof and a diamine having an aromatic ring with a para-position, and which gives a polyimide having high heat resistance. .

  A first aspect of the present invention relates to a polyimide precursor containing at least a tetracarboxylic acid (a) and an amine compound (b) having three or more amino groups.

  The tetracarboxylic acid (a) preferably contains at least one or more tetracarboxylic acids selected from the compounds represented by the general formula (1).

〔式中のＸ_１は、直接結合または、２価の基である。〕

[X ₁ in the formula is a direct bond or a divalent group. ]

Further, at least the second aspect of the present invention provides:
A tetracarboxylic ester derivative (A) selected from the compounds represented by the general formula (II-1),
Amine compound (B) having three or more amino groups selected from compounds represented by general formula (II-3)
And a polyimide precursor.

〔式中のＸ_１は直接結合もしくは、下記式（ＩＩ−２）で示される基から選ばれる２価の基を表し、Ｒ_１１〜Ｒ_３０は、それぞれ独立に水素、炭素数１〜８の１価の脂肪族基（ただし、テトラカルボン酸となる場合を除く）を表す。〕

[In the formula, X ₁ represents a direct bond or a divalent group selected from groups represented by the following formula (II-2), and R _{11 to} R ₃₀ each independently represent hydrogen or C 1-8. It represents a monovalent aliphatic group (except when it becomes tetracarboxylic acid). ]

〔式中のＸ_２は、２価の有機基である。〕

[X ₂ in the formula is a divalent organic group. ]

〔Ｚ_１は３価の窒素原子、３価以上の芳香族基、３価以上の脂肪族基、Ｚ_２およびＺ_３は直接結合または２価の基であり、Ｒ_３１〜Ｒ_３６は１価の芳香族基、脂肪族基、ハロゲン、ｎ_１は３以上、ｍ_１およびｍ_３は０〜４、ｍ_２およびｍ_４〜ｍ_６は０〜３の整数を表す。〕

[Z ₁ is a trivalent nitrogen atom, a trivalent or higher aromatic group, a trivalent or higher aliphatic group, Z ₂ and Z ₃ are a direct bond or a divalent group, and R _{31 to} R ₃₆ are monovalent. aromatic group, an aliphatic group, a halogen, _{n 1} is 3 or more, _{m 1} and _{m 3} is 0 to 4, _{m 2} and _m 4 ~m ₆ represents an integer of 0 to 3. ]

Further, a third aspect of the present invention provides a method for manufacturing a battery comprising: at least one tetracarboxylic acid (A31) selected from 3,3 ′, 4,4′-biphenyltetracarboxylic acid and an ester derivative thereof;
A tetracarboxylic acid component containing at least one tetracarboxylic acid (A32) selected from the tetracarboxylic acids different from the tetracarboxylic acids (A31) and ester derivatives thereof;
The present invention relates to a polyimide precursor containing a diamine component containing an aromatic diamine (B31) represented by the following general formula (III-1).

〔式中のＹ_１は直接結合、エーテル結合、エステル結合、アミド結合、ケトン結合、メチレン、イソプロピリデン、ジメチルシリレンまたは、炭素数１〜６のアルキレン、炭素数１２以下の芳香族基、または下記一般式（ＩＩＩ−２）で表されるいずれかの分子構造を表し、Ｒ_１〜Ｒ_３は、それぞれ独立に炭素数１２以下の芳香族基、炭素数１〜６のアルキル基、ハロゲン基、水酸基、カルボン酸基であり、ｎ_１〜ｎ_３は０〜４の整数を表す。〕

[Y ₁ in the formula is a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene or an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, or Represents any molecular structure represented by the general formula (III-2), and R _{1 to} R ₃ each independently represent an aromatic group having 12 or less carbon atoms, an alkyl group having 1 to 6 carbon atoms, a halogen group, It is a hydroxyl group or a carboxylic acid group, and n _{1 to} n ₃ represent an integer of 0 to 4. ]

〔式中のＹ_２は直接結合、エーテル結合、エステル結合、アミド結合、ケトン結合、メチレン、イソプロピリデン、ジメチルシリレンまたは、炭素数１〜６のアルキレン、炭素数１２以下の芳香族基を表し、Ｒ_４、Ｒ_５は、それぞれ独立に炭素数１〜６のアルキレン、炭素数１２以下の芳香族基を表す。〕

[Y ₂ in the formula represents a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene, or an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, R ₄ and R ₅ each independently represent an alkylene having 1 to 6 carbon atoms or an aromatic group having 12 or less carbon atoms. ]

  According to one aspect of the present invention, there is provided a polyimide precursor capable of easily producing a polyimide having a suitably high crosslink density, heat resistance, dimensional stability at high temperatures, and a crosslinked polyimide excellent in bending resistance, and a method for producing the same. be able to.

  Further, according to one embodiment of the present invention, a polyimide precursor which can easily produce a polyimide having a suitably high cross-linking density, heat resistance, dimensional stability at high temperatures, and a cross-linked polyimide excellent in bending resistance, and production thereof A method can be provided.

  Further, according to one embodiment of the present invention, it is possible to provide a polyimide precursor capable of easily producing a high heat-resistant polyimide and increasing the solid content concentration.

It is a graph which shows the thermo-mechanical characteristics of Examples I-2-6 and Comparative Example I-1. It is a graph which shows the thermo-mechanical characteristics of Examples II-1 to II-5 and Comparative example II-1. It is a stress-strain curve (SS curve) of the tensile test of the polyimide film obtained in Example III-25 and Comparative Example III-9.

  Hereinafter, the present invention will be described below by dividing it into Part I, Part II and Part III. Each part will be described independently, but in the description of each part, the components, compounds, methods, and the like described in other parts may be adopted as long as they do not contradict the spirit of the invention of the part.

In the present application, the tetracarboxylic acid residue means a tetravalent group obtained by removing four carboxyl groups (—COOH) from tetracarboxylic acid. An amine residue means a group obtained by removing an amino group (—NH ₂ ) from an amine compound. A diamine residue is a divalent group, and a triamine residue is a trivalent group.

  In the present application, the tetracarboxylic acid component refers to a carboxylic acid compound such as a tetracarboxylic acid ester, a tetracarboxylic dianhydride, or a tetracarboxylic acid as a raw material of the polyimide, and the amine component is a raw material of the polyimide. , Ie, an amine compound or a diamine compound having three or more amino groups.

  When a polyimide is synthesized by reacting a tetracarboxylic acid component with an amine component in a predetermined step, a polyimide having a tetracarboxylic acid residue and an amine residue derived from a raw material compound is obtained. In the present specification, when specifying the chemical structure of a polyimide, the chemical structure may be described by describing a tetracarboxylic acid component and an amine component instead of directly showing the structure by a chemical formula.

  In the present application, the polyimide precursor is not particularly limited with respect to its state and form as long as it contains the predetermined compound described in this specification and forms a polyimide by a subsequent manufacturing method. In the inventions of Part I, Part II and Part III, the contained tetracarboxylic acid component, amine component (diamine, triamine), and other components as necessary are specified. Or a mixture of the components or compounds to be formed, or an association or salt formed by these. In addition, an existing component (compound) may exist in a state of being divided into several parts (for example, existing in different phases). For example, a mixture in which some components are solid and other components are liquid or solution Some of the existing components may be in a different state from other components. These may be any as long as the components present in the process of producing the polyimide react to form the polyimide. The form is not particularly limited, but may be a solid such as a powder, a lump, a pellet, a film, or a liquid such as a liquid, a solution or a dispersion, or a complex with other substances. Absent.

<< Part I >>
An object of the invention of Part I is to provide a polyimide precursor which can easily produce a polyimide having a suitably high crosslinking density, a crosslinked polyimide excellent in heat resistance and dimensional stability at high temperatures, and a method for producing the same.

  The present inventors have conducted intensive studies, and as a result of using a compound having a tetracarboxylic acid and three or more amino groups instead of a polyamic acid which is a polyimide precursor that has been generally used until now, The inventors have found that polyimides appropriately crosslinked at high density can be easily produced, and have led to the invention of Part I.

  That is, the invention of Part I relates to the following matters.

  1. A polyimide precursor comprising at least a tetracarboxylic acid (a) and an amine compound (b) having three or more amino groups.

  2. The polyimide precursor according to the above 1, wherein the polyimide precursor contains at least one or more kinds of tetracarboxylic acids selected from the compounds represented by the general formula (1) as the tetracarboxylic acid (a).

〔式中のＸ_１は、直接結合または、２価の基である。〕
３． テトラカルボン酸（ａ）として、ピロメリット酸および一般式：

[X ₁ in the formula is a direct bond or a divalent group. ]
3. As the tetracarboxylic acid (a), pyromellitic acid and the general formula:

で表され且つＸ_１が直接結合または下記一般式（２）で示されるいずれかの２価の基であるテトラカルボン酸からなる群より選ばれる少なくとも１種類を含むことを特徴とする上記１または２に記載のポリイミド前駆体。

Wherein X ₁ comprises at least one member selected from the group consisting of a direct bond or a tetracarboxylic acid which is any divalent group represented by the following general formula (2): 3. The polyimide precursor according to 2.

〔式中のＸ_２は、２価の有機基である。〕
４． 前記アミン化合物（ｂ）として、一般式（３）で表されるアミン化合物から選ばれる少なくとも１種類を含むことを特徴とする上記１〜３のいずれか１項に記載のポリイミド前駆体。

[X ₂ in the formula is a divalent organic group. ]
4. 4. The polyimide precursor according to any one of the above items 1 to 3, wherein the amine compound (b) includes at least one selected from amine compounds represented by the general formula (3).

〔式中のＺ_１は３価以上の基、Ｚ_２およびＺ_３は直接結合または２価の基であり、Ｒ_３１〜Ｒ_３６はそれぞれ独立に１価の基を表し、ｎ_１は３以上、ｍ_１およびｍ_３は０〜４、ｍ_２およびｍ_４〜ｍ_６は０〜３の整数を表す。〕
５． さらに、ジアミン（Ｃ）を含むことを特徴とする上記１〜４のいずれか１項に記載のポリイミド前駆体。

[In the formula, Z ₁ is a trivalent or more valent group, Z ₂ and Z ₃ are a direct bond or a divalent group, R _{31 to} R ₃₆ each independently represent a monovalent group, and n ₁ is 3 or more. , M ₁ and m ₃ represent an integer of 0 to 4, and m ₂ and m _{4 to} m ₆ represent an integer of 0 to 3. ]
5. The polyimide precursor according to any one of the above items 1 to 4, further comprising a diamine (C).

  6. The amine compound (b) is contained in an amount of 1 mol% or more based on the total molar amount of all the diamine components composed of the amine compound (b) and, if present, the diamine (C). 6. The polyimide precursor according to any one of 5.

  7. 7. The polyimide precursor according to the above item 5 or 6, wherein the diamine (C) contains at least one selected from compounds represented by the general formula (4).

〔式中のＹ_１は直接結合または２価の基を表し、Ｒ_５〜Ｒ_７はそれぞれ独立に１価の基を表し、ｍ_５〜ｍ_７は０〜４の整数を表す。〕
８． 粒子径５ｍｍ以下の粉末である上記１〜７のいずれか１項に記載のポリイミド前駆体。

[In the formula, Y ₁ represents a direct bond or a divalent group, R _{5 to} R ₇ each independently represent a monovalent group, and m _{5 to} m ₇ represent an integer of 0 to 4. ]
8. 8. The polyimide precursor according to any one of the above items 1 to 7, which is a powder having a particle diameter of 5 mm or less.

  9. A polyimide precursor solution, comprising: the polyimide precursor according to any one of the above items 1 to 7; and a solvent (D).

  10. 9. A method for producing a polyimide having a crosslinked structure, comprising a step of imidizing the polyimide precursor according to any one of the above items 1 to 8 or the polyimide precursor in the solution of the above item 9.

11. A polyimide having a structural unit derived from a tetracarboxylic acid component and a structural unit derived from an amine component,
The structural unit derived from the amine component may be a structural unit derived from an amine compound (bi) having three or more amino groups and a diamine (Ci), respectively, in a range where the value of the following formula is 0.01 to 1. A polyimide having a crosslinked structure, characterized by being included in

[Total moles of amine compound (bi)] / ([Total moles of amine compound (bi)] + [Total moles of diamine (Ci)])
12. 12. The polyimide having a crosslinked structure according to the above item 11, wherein the polyimide has a glass transition temperature of 180 ° C. or higher.

  13. 13. The polyimide having a crosslinked structure according to the above item 11 or 12, wherein an average linear expansion coefficient at 50 ° C. to 200 ° C. when measured on a film having a thickness of 10 μm is 60 ppm / K or less.

  14． 14. The polyimide having a crosslinked structure according to any one of 11 to 13, wherein a 5% weight loss temperature determined by TGA is 450 ° C. or higher.

  15. A polyimide film comprising the polyimide having a crosslinked structure according to any one of the above items 11 to 14.

  16. A laminate comprising any one of a glass layer, a metal layer, a resin layer, and a ceramic layer, and the polyimide having a crosslinked structure according to any one of the above items 11 to 14.

<Effects of the invention of Part I>
According to the invention of Part I, it is possible to provide a polyimide precursor capable of easily producing a polyimide having a suitably high crosslinking density, a crosslinked polyimide excellent in heat resistance, dimensional stability at high temperatures, and bending resistance, and a method for producing the same. .

<Details of Invention of Part I>
In the following description of the present application, the amine compound (b) having three or more amino groups (such as a triamine compound and a tetraamine compound) may be simply referred to as “amine compound (b)”.

(Polyimide precursor)
The polyimide precursor of the invention of Part I is a polyimide precursor that forms a polyimide by an imidization reaction, and includes at least a tetracarboxylic acid (a) and an amine compound (b) having three or more amino groups. .

  The polyimide precursor preferably contains at least one or more tetracarboxylic acids represented by the general formula (1) as the tetracarboxylic acid (a).

In the formula, X ₁ is a direct bond or a divalent group.

  As the tetracarboxylic acid (a), pyromellitic acid and the general formula:

で表され且つＸ_１が直接結合または下記一般式（２）：

And X ₁ is a direct bond or the following general formula (2):

〔式中のＸ_２は、２価の有機基である。〕
で示されるいずれかの２価の基であるテトラカルボン酸からなる群より選ばれる少なくとも１種類以上を含む場合、耐熱性に優れることから、より好ましい。

[X ₂ in the formula is a divalent organic group. ]
It is more preferable to include at least one or more selected from the group consisting of tetracarboxylic acids that are any of the divalent groups represented by the formula (1) because of excellent heat resistance.

X ₂ is preferably a divalent organic group containing an aromatic ring or an alicyclic structure, and more preferably a general formula:

R _{111 to} R ₁₂₄ are preferably a direct bond, and a divalent group represented by

からなる群より選ばれる基である。

A group selected from the group consisting of

  The tetracarboxylic acid (a) is preferably 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2,3,3', 4'-biphenyltetracarboxylic acid, 2,2 ', 3,3 '-Biphenyltetracarboxylic acid, pyromellitic acid, oxydiphthalic acid, 3,3', 4,4'-diphenylsulfonetetracarboxylic acid, m-terphenyl-3,3 ', 4,4'-tetracarboxylic acid, 4,4 '-(2,2-hexafluoroisopropylene) diphthalic acid, 2,2'-bis (3,4-dicarboxyphenyl) propane, 4,4'-(dimethylsiladiyl) diphthalic acid, 4,4 '-(1,4-phenylenebis (oxy)) diphthalic acid and the like, particularly preferably 3,3', 4,4'-biphenyltetracarboxylic acid and 2,3,3 ', 4'-biphenyltetracarboxylic acid , Pyromellitic acid, oxydiphthalic acid, 4,4 '- is a (2,2-hexafluoro isopropylene) diphthalic acid.

  The use of 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2,3,3', 4'-biphenyltetracarboxylic acid, pyromellitic acid, etc. is preferable because of its excellent heat resistance and dimensional stability. It is preferable to use 4,4'-oxydiphthalic acid, 4,4 '-(2,2-hexafluoroisopropylene) diphthalic acid, etc., since solubility and coloring of polyimide can be reduced.

  The polyimide precursor of the invention of Part I is not particularly limited, but as an amine compound (b) having three or more amino groups, since it has excellent heat resistance, at least one compound containing an aromatic ring is used. It is preferable to contain at least one kind of the compound represented by the general formula (3).

In the formula, Z ₁ is a trivalent or higher valent group, Z ₂ and Z ₃ are a direct bond or a divalent group, R _{1 to} R ₆ each independently represent a monovalent group, and n ₁ is Z ₁ Represents an integer of 3 or more, preferably 6 or less, more preferably an integer of 3 or 4, m ₁ and m ₃ are 0 to 4, m ₂ and m _{4 to} m ₆ are 0 to Represents an integer of 3.

Z ₁ is preferably a trivalent nitrogen atom (N), a trivalent or higher aromatic group which may have a hetero atom or a trivalent or higher aliphatic group which may have a hetero atom. Represent. Although not particularly limited, Z ₁ in the general formula (3) is preferably a trivalent or higher valent group represented by the general formula (5).

R _{51 to} R ₁₀₀ in the formula each independently represent a direct bond or one of divalent groups represented by the following formula (6), and R ₁₀₁ represents hydrogen or an aliphatic group or an aromatic group (any of Also preferably up to about 18 carbon atoms).

However, R _{51 to} R ₅₃ are a direct bond or a compound represented by the formula:

で示される基から選ばれることが好ましい。

It is preferable to be selected from the groups represented by

Although not particularly limited, Z ₂ and Z ₃ in the general formula (3) are preferably a direct bond or a divalent group represented by the above formula (6), and among them, have excellent heat resistance. Therefore, it is more preferable to have a direct bond, an ether bond, an ester bond, an amide bond, an isopropylidene bond, and a hexafluoroisopropylidene bond, and it is particularly preferable to have a direct bond or an ether bond.

As R _{1 to} R ₆ in the formula (3), an aromatic group having 12 or less carbon atoms (eg, phenyl group, benzyl group, phenoxy group), an alkyl group having 1 to 6 carbon atoms, fluorine, chlorine and the like are preferable. .

m ₁ is preferably 0, 1 or 2, m ₂ is preferably 0 or 1, m ₃ is preferably 0, 1 or 2, m ₄ is preferably 0 or 1, m ₅ and m ₆ are independently preferred Is 0 or 1.

  Since the amine compound (B) has excellent reactivity, the ring bonded to the amino group in the chemical structure is preferably a heterocyclic ring or an aromatic ring having no quinone structure, and a tetracarboxylic acid derivative It is more preferable that the chemical structure does not include a hydroxyl group, a thiol, or a secondary amine in order to suppress side reactions other than the imidation reaction.

Specific examples of the amine compound (B) include:
1,3,5-triaminobenzene, 4,4 ′, 4 ″ -triaminotriphenylamine,
3,5-di (4-aminophenoxy) aniline, 3,5-di (3-methyl, 4-aminophenoxy) aniline, 3,5-di (3-methoxy, 4-aminophenoxy) aniline, 3,5 -Di (2-methyl, 4-aminophenoxy) aniline, 3,5-di (2-methoxy, 4-aminophenoxy) aniline, 3,5-di (3-ethyl, 4-aminophenoxy) aniline,
1,3,5-tri (4-aminophenoxy) benzene, 1,3,5-tri (3-methyl, 4-aminophenoxy) benzene, 1,3,5-tri (3-methoxy, 4-aminophenoxy) ) Benzene, 1,3,5-tri (2-methyl, 4-aminophenoxy) benzene, 1,3,5-tri (2-methoxy, 4-aminophenoxy) benzene, 1,3,5-tri (3 -Ethyl, 4-aminophenoxy) benzene,
1,3,5-tri (4-aminophenylamino) benzene, 1,3,5-tri (3-methyl, 4-aminophenylamino) benzene, 1,3,5-tri (3-methoxy, 4- Aminophenylamino) benzene, 1,3,5-tri (2-methyl, 4-aminophenylamino) benzene, 1,3,5-tri (2-methoxy, 4-aminophenylamino) benzene, 1,3 5-tri (3-ethyl, 4-aminophenylamino) benzene,
1,3,5-tri (4-aminophenyl) benzene, 1,3,5-tri (3-methyl, 4-aminophenyl) benzene, 1,3,5-tri (3-methoxy, 4-aminophenyl) ) Benzene, 1,3,5-tri (2-methyl, 4-aminophenyl) benzene, 1,3,5-tri (2-methoxy, 4-aminophenyl) benzene, 1,3,5-tri (3 -Ethyl, 4-aminophenyl) benzene,
1,3,5-tri (4-aminophenyl) amine, 1,3,5-tri (3-methyl, 4-aminophenyl) amine, 1,3,5-tri (3-methoxy, 4-aminophenyl) ) Amine, 1,3,5-tri (2-methyl, 4-aminophenyl) amine, 1,3,5-tri (2-methoxy, 4-aminophenyl) amine, 1,3,5-tri (3 -Ethyl, 4-aminophenyl) amine,
Tris (4- (4-aminophenoxy) phenyl) methane, tris (4- (3-methyl, 4-aminophenoxy) phenyl) methane, tris (4- (3-methoxy, 4-aminophenoxy) phenyl) methane, Tris (4- (2-methyl, 4-aminophenoxy) phenyl) methane, tris (4- (2-methoxy, 4-aminophenoxy) phenyl) methane, tris (4- (3-ethyl, 4-aminophenoxy) Phenyl) methane,
Tris (4- (4-aminophenoxy) phenyl) ethane, tris (4- (3-methyl, 4-aminophenoxy) phenyl) ethane, tris (4- (3-methoxy, 4-aminophenoxy) phenyl) ethane, Tris (4- (2-methyl, 4-aminophenoxy) phenyl) ethane, tris (4- (2-methoxy, 4-aminophenoxy) phenyl) ethane, tris (4- (3-ethyl, 4-aminophenoxy) Phenyl) ethane,
4- (4-aminophenoxy) benzene-1,3-diamine, 4- (4-aminophenoxy) benzene-2,4-diamine,
3,5-diamino-N- (4-aminophenyl) benzamide, 3,5-diamino-N- (4-aminophenyl) -4-methoxybenzamide,
3,3′-diaminobenzidine and the like, preferably 1,3,5-triaminobenzene, 4,4 ′, 4 ″ -triaminotriphenylamine, 1,3,5-tri (4 -Aminophenoxy) benzene, 4- (4-aminophenoxy) benzene-1,3-diamine, 3,5-diamino-N- (4-aminophenyl) benzamide, 3,5-diamino-N- (4-amino Phenyl) -4-methoxybenzamide is preferred, 4,4 ′, 4 ″ -triaminotriphenylamine, 4- (4-aminophenoxy) benzene-1,3-diamine, more preferably
4,4 ', 4 "-triaminotriphenylamine, 4- (4-aminophenoxy) benzene-1,3-diamine, 3,5-diamino-N- (4-aminophenyl) benzamide, 3,5- Diamino-N- (4-aminophenyl) -4-methoxybenzamide These amine compounds may be used alone or in combination of two or more.

  The polyimide precursor of the invention of Part I can optionally include a diamine (C). Although not particularly limited, it is preferable that the diamine (C) contains at least one or more compounds represented by the general formula (4) because of excellent heat resistance.

In the formula, Y ₁ represents a direct bond or a divalent group, R _{5 to} R ₇ each independently represent a monovalent group, and m _{5 to} m ₇ represent an integer of 0 to 4.

Although not particularly limited, Y ₁ in the general formula (4) is preferably selected from a group represented by the above formula (6) and a divalent group represented by the following general formula (7). .

In the formula, R ₉ each independently (independently within one molecule) represents a direct bond or a divalent group represented by the above formula (6). R ₉ preferably has a direct bond, an ether bond, an ester bond, an amide bond, an isopropylidene bond, a hexafluoroisopropylidene bond, and more preferably a direct bond or an ether bond, because of excellent heat resistance. preferable.

Y ₁ preferably has a direct bond, an ether bond, an ester bond, an amide bond, an isopropylidene bond, a hexafluoroisopropylidene bond, and more preferably has a direct bond or an ether bond, since it has excellent heat resistance. preferable.

R _{5 to} R ₇ are preferably an aromatic group having 12 or less carbon atoms (for example, a phenyl group, a benzyl group, or a phenoxy group), an alkyl group having 1 to 6 carbon atoms, fluorine, or chlorine.

m _{5 to} m ₇ are preferably 0, 1 or 2.

  Specific examples of the diamine (C) include, for example, paraphenylenediamine, metaphenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 4,4′-diaminobiphenyl, 3,3′-dimethyl-4 , 4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 2,2-bis (trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis- (4-aminophenyl) propane, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl ether, 3,4 '-Diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,5-diamino Phthalene, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2,2-bis (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 9,9-bis (4-aminophenyl) fluorene and the like. These diamine compounds may be used alone or in combination of two or more. Among them, paraphenylenediamine, metaphenylenediamine, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylether, 4,4'-diaminodiphenylether, 1,3-bis (3-aminophenoxy) benzene , 1,3-bis (4-aminophenoxy) benzene) and 2,2-bis [4- (4-aminophenoxy) phenyl] propane are preferred.

  In the polyimide precursor of the invention of Part I, the value of [total mole number of amine compound (b)] / ([total mole number of amine compound (b)] + [total mole number of diamine (C)]) is: It is preferably 0.01 to 1, more preferably 0.03 to 1, and particularly preferably 0.1 to 1. Within this range, dimensional stability at high temperatures and solvent resistance are excellent.

  Although the polyimide precursor of the invention of Part I is not particularly limited, the value of the total number of carboxylic acid groups (mole number) of the tetracarboxylic acid component / the total number of amine groups (mole number) of the amine component is 1 to 3. Is preferable, 1.6-2.4 is more preferable, 1.8-2.2 is still more preferable, and it is especially preferable that it is substantially 2. Within this range, heat resistance, dimensional stability at high temperatures, and solvent resistance are excellent.

  In the polyimide precursor of the invention of Part I, the molecular weight α between crosslink points when a polyimide is formed is preferably in the range of 500 to 100,000 g / mol, more preferably in the range of 1,300 to 10,000. , More preferably from 1,500 to 5,000, particularly preferably from 1,800 to 4,000. The molecular weight α between cross-linking points has a substantially positive correlation with the elongation of the resin, and a substantially negative correlation with the elasticity of the resin, so that within this range, high elongation, high elasticity, bending resistance, and high temperature Dimensional stability can be compatible. The cross-linking point molecular weight α is preferably a known method (for example, a method described in Polymer Chemistry PJ Flori, Oka Koten-Kanamaru Competition, published by Maruzen Co., Ltd., Showa 31). It can be used, and the value may be a value obtained as a theoretical value or a value obtained from an experimental value such as viscoelasticity measurement.

  The molecular weight α between crosslink points determined as a theoretical value will be described below.

When k kinds (k is an integer) of monomer X components are contained in the resin, the blending amount of the i-th (i is an integer of 1 to k) monomer X component is defined as a _i (unit: g). . Further, when the resin contains l (l is an integer) monomer Y components, the amount of the j-th (j is an integer of 1 to 1) monomer Y component is defined as b _j (unit: g). Then, the weight W (unit: g) of all the resins is obtained by the equation (1).

The functional group equivalent of the i-th monomer X is E _i (unit: g / mol), and the number of functional groups in one molecule of the i-th monomer X is x _i . The functional group equivalent of the j-th monomer Y is represented by H _j (unit: g / mol), and the number of functional groups of one molecule of the j-th monomer Y is represented by y _j . The number c (unit: mol) of cross-linking points contained in all the resins is determined when the mixing ratio of the monomer X and the monomer Y is stoichiometric, when the monomer Y is excessive, and when the monomer X is excessive. The way of finding is different. Which method is to be adopted is determined by a compounding ratio index β that indicates the compounding ratio of the monomer X and the monomer Y, which is obtained by the equation (2).

  Here, when β = 1, the compounding ratio of the monomer X and the monomer Y is a stoichiometric amount, and the number c of the cross-linking points is obtained by the equation (3). The number c of cross-linking points represents the number of cross-linking points generated by the reaction between the functional groups of all the monomers X and the functional groups of all the monomers Y that can react.

  In the case of β> 1, the monomer Y is in excess of the stoichiometric amount, and the number c of crosslinking points can be obtained by the equation (4).

  When β <1, the monomer X is in excess of the stoichiometric amount, and the number c of cross-linking points is determined by the equation (5).

Here, E _i × x _i and H _j × y _j
Represents the average molecular weight of the i-th monomer X component and the average molecular weight of the j-th monomer Y component, respectively. Also, (x i _-2), the functional groups of all monomers X of the i-th monomer X component 1 in the molecule is reacted with the monomer Y, it represents the number of crosslinking points caused by being incorporated into the crosslinked structure. (Y _j -2) represents the number of cross-linking points generated when all the functional groups in one molecule of the j-th monomer Y component react with the monomer X and are incorporated into the cross-linked structure. For example, when the i-th monomer X is a tetrafunctional monomer X, one molecule has four functional groups, and the number of generated cross-linking points is 4-2. Further, when the j-th monomer Y component has two functional groups per molecule, the number of generated crosslinking points is 2-2 and zero.

  Using W and c determined by the above-described equations, the molecular weight α between the crosslinking points is determined by the equation (6).

In the case of polyimide, when the monomer X is a tetracarboxylic acid component and the monomer Y is an amine component (diamine and a compound having three or more amino groups), the compounding amount of the monomer X is a _i and the compounding amount of the monomer Y is And b _j is a value obtained by dividing the weight of the eliminated component (eg, water or alcohol) generated when imidization is performed. In the monomer X (tetracarboxylic acid component), two carboxylic acid groups forming an imide ring are calculated as one functional group.

  The molecular weight α between crosslink points determined as a value determined from experimental values will be described below.

  From the viscoelasticity measurement results, the absolute temperature T at the point where the storage elastic modulus becomes a minimum, and the storage elastic modulus E ′ at the minimum point are obtained, and when the resin density ρ and the gas constant R are obtained, the molecular weight α between crosslink points is , (7). When the polyimide composition contains a functional group that causes additional cross-linking such as a ketone bond or an unsaturated bond, it is preferable to obtain the functional group from experimental values.

The molecular weight α between crosslink points in the invention of Part I is not particularly limited, but a value obtained from the above-mentioned formula (6) can be suitably adopted. When the polyimide composition contains a functional group capable of forming an additional crosslink such as a ketone bond or an unsaturated bond, it is usually preferable to obtain the functional group from the experimental value as described above. The value obtained from this may be adopted as the molecular weight α between crosslink points. Additional crosslinking functional group is 75% or less are preferred number of amino groups in the amine component (-NH _2), more preferably not more than 50%, more preferably 25% or less, particularly preferably 10% It is as follows.

  The average molecular weight of the polyimide precursor of the invention of Part I is not particularly limited, but is substantially 50 to 5,000, more preferably 100 to 2,000 because it is substantially composed of a low molecular compound. , 200 to 1,000 are particularly preferred. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained. The molecular weight here may be a number average molecular weight determined by GPC measurement, a molecular weight determined from TOF-MASS, FAB-MASS, or a value of other known analysis methods. Further, under the condition that polymerization does not substantially occur, the average molecular weight of each component forming the polyimide can be suitably adopted.

  The logarithmic viscosity (ηinh) of the polyimide precursor of the invention of Part I is substantially less than 0.2, preferably less than 0.15, more preferably less than 0.1 because it is composed of a low molecular weight compound. is there. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained.

  Since the polyimide precursor of the invention of Part I is substantially composed of a low molecular compound, it is preferable that the polyimide precursor does not contain a repeating unit of polyamic acid. For the confirmation of the repeating unit of the polyamic acid, a known analysis method such as NMR or FT-IR can be suitably used. The ratio of the repeating unit (mol) of the polyamic acid is preferably 0.05 mol / mol or less per total mol of amino groups of the amine component (or 1/2 times the total mol of carbonyl groups of the tetracarboxylic acid component). It is at most 0.03 mol / mol, more preferably at most 0.01 mol / mol, particularly preferably at most the detection lower limit. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained.

  The polyimide precursor of the invention of Part I may be a powder, preferably an average particle diameter of 5 mm or less, more preferably 1 mm or less, particularly preferably 0.5 mm or less, and a maximum particle diameter of 5 mm or less, more preferably It is 1 mm or less, particularly preferably 0.5 mm or less. These particle diameters can be obtained by using a known measurement method such as a laser diffraction method, an image imaging method, or a gravity sedimentation method, and using a result obtained by using a known analysis method.

(Polyimide precursor solution)
The polyimide precursor solution is described together with Part I, Part II and Part III. In this section, unless otherwise specified, "polyimide precursor" means all polyimide precursors of Part I, Part II and Part III.

  The polyimide precursor is also preferably in the form of a solution and a dispersion (together, a polyimide precursor solution). That is, the polyimide precursor solution may be a solution in which the polyimide precursor is dissolved or a liquid in which the polyimide precursor is dispersed, and the polyimide precursor powder is dissolved in a solvent, dispersed or dissolved. Alternatively, a tetracarboxylic acid component and an amine component may be separately charged, dissolved and dispersed.

  The polyimide precursor (and solution) may optionally contain a chemical imidizing agent (an acid anhydride such as acetic anhydride, or an amine compound such as pyridine or isoquinoline), an antioxidant, or a filler (inorganic particles or organic particles). , Dyes, pigments, coupling agents such as silane coupling agents, primers, flame retardants, defoamers, leveling agents, rheology control agents (flow aids), release agents, surfactants, etc. can be added. . These additives can be added even when the polyimide precursor is not in a solution state but is partially or entirely solid, for example, a powder.

  The solvent (D) used in the polyimide precursor solution is preferably an amide solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, γ-valerolactone, δ- Valerolactone, γ-caprolactone, ε-caprolactone, cyclic ester solvents such as α-methyl-γ-butyrolactone, ethylene carbonate, carbonate solvents such as propylene carbonate, glycol solvents such as triethylene glycol, phenol, o-cresol, m Phenol solvents such as -cresol, p-cresol, 3-chlorophenol and 4-chlorophenol, acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide and the like can be used. Further, other common organic solvents such as butyl acetate, ethyl acetate, isobutyl acetate, propylene glycol methyl acetate, ethyl cellosolve, butyl cellosolve, 2-methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, tetrahydrofuran, dimethoxyethane, dimethoxyethane Ethoxyethane, dibutyl ether, diethylene glycol dimethyl ether, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl ethyl ketone, acetone, butanol, ethanol, xylene, toluene, chlorobenzene, terpenes, mineral spirits, petroleum naphtha solvents, etc. Can be used.

  Since the polyimide precursor solution is preferably composed of a low molecular compound, the solution has a low viscosity even at a high concentration. Although not particularly limited, the viscosity of the solution measured at 30 ° C. with an E-type viscometer is preferably 1,000 Pa · sec or less, more preferably 0.01 to 500 Pa · sec, and particularly preferably 0.05 Pa · sec. ３００300 Pa · sec. If it is in this range, it is excellent in handling properties such as subsequent production of polyimide. On the other hand, the solid content (preferably determined by the method described in Examples) is preferably 1% or more, more preferably 5% to 80%, and particularly preferably 10% to 50%.

  The polyimide precursor solution can be suitably used as a polyimide precursor for producing a film. Although not particularly limited, the viscosity of the dope (polyimide precursor solution) at 30 ° C. is preferably 1,000 Pa · sec or less, more preferably 10 to 500 Pa · sec, and particularly preferably 50 to 300 Pa · sec. . On the other hand, the solid content concentration (preferably determined by the method described in Examples) is preferably 5% or more, more preferably 10% to 80%, and particularly preferably 20% to 50%. Within this range, the handleability during the subsequent production of the polyimide film is excellent.

  The polyimide precursor can be suitably used as a heat-resistant paint (raw material of paint, additive). Although not particularly limited, since the polyimide precursor is composed of a low molecular compound, a paint having a higher concentration and a lower viscosity can be obtained as compared with a general polyimide precursor. Therefore, for example, dip coating, bar coating, spin coating, blade coating, doctor coating, die coating gravure coating, spray coating, ultrasonic spray coating, various coating methods such as electrostatic coating, inkjet, letterpress, intaglio, lithographic, stencil, It can be suitably used for various printing methods such as a screen. As the solvent used in the coating material, for example, the above-described solvents described for the polyimide precursor solution can be used.

(Polyimide precursor / inorganic particle composite)
The polyimide precursors (and solutions) of the inventions of Part I, Part II and Part III may contain inorganic particles (E) as necessary. Examples of the inorganic particles include silica, alumina (aluminum oxide), beryllia (beryllium oxide), magnesia (magnesium oxide), silicon nitride, aluminum nitride, boron nitride, expandable graphite, and carbon nanotube. From the viewpoint of dispersibility and colorability, alumina (aluminum oxide), magnesia (magnesium oxide), silicon nitride, aluminum nitride, and boron nitride are preferred. These may be used alone or as a mixture of two or more. Further, as the particle diameter of the inorganic particles (E), the average particle diameter determined by a laser diffraction particle size distribution analyzer is preferably 20 μm or less, more preferably 10 μm or less, and still more preferably 5 μm or less. The inorganic particles are preferably used in an amount of 1 part by mass or more, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, particularly preferably 50 parts by mass or more, based on 100 parts by mass of the solid content of the polyimide precursor solution. Is preferred.

(Polyimide having a crosslinked structure)
The polyimide having a crosslinked structure of the invention of Part I is a polyimide having a structural unit derived from a tetracarboxylic acid component and a structural unit derived from an amine component, and the structural unit derived from the amine component has three or more structural units. Structural units derived from the amine compound (bi) and the diamine (Ci) each having an amino group are included in a range where the value of the following formula is 0.01 to 1.

  [Total moles of amine compound (bi)] / ([Total moles of amine compound (bi)] + [Total moles of diamine (Ci)])

  Here, the value of the formula, [total mole number of amine compound (bi)] / ([total mole number of amine compound (bi)] + [total mole number of diamine (Ci)]) is preferably 0.1. To 1, more preferably 0.2 to 1, still more preferably 0.25 to 1, particularly preferably 0.5 to 1. Within this range, a high crosslinking density can be achieved, so that the glass transition temperature is high and the dimensional stability is excellent.

  Although the polyimide having a crosslinked structure of the invention of Part I is not particularly limited, it is preferably produced by the above-mentioned polyimide precursor. Therefore, the tetracarboxylic acid component is preferably the above-mentioned tetracarboxylic acid (a). Similarly, the amine compound (bi) having three or more amino groups is preferably the amine compound (b) having three or more amino groups, and the diamine (Ci) is preferably the diamine (C) Is preferred.

  The polyimide having a crosslinked structure has a molecular weight α between crosslink points of preferably 500 to 100,000 g / mol, more preferably 1,300 to 10,000, and still more preferably 1,500 to 5,5. 000, particularly preferably 1,800-4,000. Within this range, dimensional stability at high temperatures and bending resistance are excellent.

  The polyimide having a crosslinked structure is not particularly limited, but has a glass transition temperature of 180 ° C. or higher, preferably 200 ° C. or higher, more preferably 220 ° C. or higher, still more preferably 230 ° C. or higher, and particularly preferably 260 ° C. or higher. It is. This range is preferable because of excellent dimensional stability.

  On the other hand, since the polyimide having a crosslinked structure of the invention of Part I has a small deformation at the time of heating, even a polyimide having a relatively low glass transition temperature can be used at a high temperature, and the glass transition temperature is from 180 ° C. 300 ° C is preferable, 180 ° C to 260 ° C is more preferable, 180 ° C to 240 ° C is further preferable, and 180 ° C to 230 ° C is particularly preferable.

  Here, the glass transition temperature is, for example, using a film of a thermoplastic polyimide layer alone or a multilayer polyimide film, measuring dynamic viscoelasticity (DMS), thermomechanical analysis (TMA), differential scanning calorimetry (DSC), Any glass transition temperature determined by differential thermal analysis (DTA) using known conditions and analysis methods may be employed.

  Since the polyimide having a cross-linked structure can have a suitably high-density cross-linked structure, the thermal expansion is small, and the average linear expansion coefficient at 50 ° C. to 200 ° C. (when Tg is 200 ° C. or less, 50 ° C. to Tg Is not particularly limited, but is preferably 70 ppm / K or less, preferably less than 60 ppm / K, more preferably 55 ppm / K or less, 50 ppm / K or less, and 45 ppm / K or less, still more preferably. It is 40 ppm / K or less, particularly preferably 10 ppm / K or less.

  Since the polyimide having a crosslinked structure can have a suitably high-density crosslinked structure, it is excellent in heat resistance, and the 5% weight loss temperature determined by TGA is preferably 430 ° C or higher, more preferably 450 ° C or higher, It is more preferably at least 470 ° C, particularly preferably at least 500 ° C, and most preferably at least 530 ° C in the invention of Part I.

  A polyimide having a crosslinked structure can have a suitably high-density crosslinked structure, and thus has excellent solvent resistance. Although not limited, it preferably has solvent resistance to the solvent (D) used in the above-mentioned polyimide precursor solution, and more preferably has solvent resistance to amide solvents such as NMP.

  The polyimide having a crosslinked structure is not particularly limited, but has heat resistance and colorless transparency, and thus can be suitably used for substrates for displays, lighting, optical devices, and solar power generation. Although not particularly limited, the total light transmittance when the film thickness is 10 μm is preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more. On the other hand, the light transmittance at 420 nm when the film thickness is 10 μm is 60% or more, preferably 70% or more, more preferably 75% or more, and particularly preferably 80% or more.

  The polyimide having a crosslinked structure can have various shapes, and one of the preferred forms is a film. That is, the polyimide film of the present invention contains the polyimide having a crosslinked structure of the present invention, and the resin component constituting the film is preferably substantially composed of the polyimide. Preferably, the film thickness is from 1 to 250 μm, more preferably from 5 to 150 μm, and particularly preferably from 7.5 to 75 μm, for excellent productivity.

  The laminate of the invention is a laminate in which any one of a glass layer, a metal layer, a resin layer, and a ceramic layer is laminated with the crosslinked polyimide of the invention. The film thickness of this laminated body is more preferably 5 to 150 μm, and particularly preferably 10 to 150 μm, because of excellent productivity.

(Method for producing polyimide having a crosslinked structure)
The polyimide having a crosslinked structure is produced by imidizing the above-mentioned polyimide precursor. Although not particularly limited, as a production method, a known polyimide production method can be suitably adopted except for using the polyimide precursor of the present invention.

  Specifically, a polyimide is obtained by subjecting the polyimide precursor (solution) obtained above to a polycondensation reaction and a ring closing reaction (formation of an imide ring) by a thermal or chemical method. (Thermal imidization method) for heat-treating the compound and a chemical method using a dehydrating agent (chemical imidization method). Further, a method of imidization by heating under reduced pressure can also be used. Hereinafter, each method will be described.

  Examples of the thermal method include a method in which a polycondensation reaction and an imidation reaction are caused to proceed by heat treatment of the polyimide precursor, and a solvent is evaporated at the same time. By this method, a solid polyimide can be obtained. The heating conditions are not particularly limited, but it is preferable to remove the organic solvent at a temperature of 200 ° C. or less for 3 minutes to 120 minutes and then at a temperature of 400 ° C. or less for 1 minute to 200 minutes. .

  Examples of the chemical method include a method in which a polycondensation reaction and an imidation reaction are advanced by adding a stoichiometric or more dehydrating agent and a catalyst to the polyimide precursor, and at the same time, an organic solvent is evaporated. Can be. By this method, a solid polyimide can be obtained. Examples of the dehydrating agent used in the chemical method include aliphatic acid anhydrides such as acetic anhydride, and aromatic acid anhydrides such as benzoic anhydride. Examples of the catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic tertiary amines such as pyridine, α-picoline, β-picoline, γ-picoline, and isoquinoline. Tertiary amines and the like can be mentioned. The conditions for the chemical method are preferably a temperature of 100 ° C. or less, and the evaporation of the organic solvent is preferably performed at a temperature of 200 ° C. or less for a time period of about 5 to 120 minutes.

  As another method for obtaining polyimide, there is a method in which the solvent is not evaporated in the above-mentioned thermal or chemical method. Specifically, a polyimide solution obtained by performing a thermal imidization treatment or a chemical imidization treatment with a dehydrating agent in a solvent is put into a poor solvent, a polyimide resin is precipitated, and an unreacted monomer is removed. It is a method of purifying and drying to obtain a solid polyimide. As the poor solvent, a material which is mixed well with the solvent but is poorly soluble in polyimide is selected.Examples include, but are not limited to, acetone, methanol, ethanol, isopropanol, benzene, methyl cellosolve, and methyl ethyl ketone. Not done.

  In addition, a method in which the polycondensation reaction and the imidization reaction are advanced by heating under reduced pressure may also be used. According to this method, water (water and / or alcohol in the case of Part II) generated by polycondensation and imidization can be positively removed from the system, so that hydrolysis of the polyimide precursor can be suppressed. And a high molecular weight polyimide is obtained.

  The heating condition of the method of heat imidization under reduced pressure is preferably 80 to 400 ° C., more preferably 100 ° C. or more, at which imidization is efficiently performed, and water is efficiently removed, and still more preferably 120 ° C. or more. . The maximum temperature is preferably equal to or lower than the thermal decomposition temperature of the target polyimide, and the usual completion temperature of imidization, that is, about 250 to 350 ° C. is usually applied. The pressure is preferably reduced at a low pressure, specifically, 0.9 to 0.001 atm, preferably 0.8 to 0.001 atm, more preferably 0.7 to 0.01 atm. .

(Use of polyimide precursor, laminate, and method for producing the same)
The polyimide precursors of the inventions of Part I, Part II, and Part III can be used for various purposes, for example, as described above, for producing a polyimide film, a coating material for producing a polyimide layer in a polyimide laminate, a battery, and the like. It can be used as a binder and an adhesive in various applications.

  The polyimide laminate has a structure in which a polyimide layer is laminated with a base layer or a base formed of a material such as glass, metal, resin, or ceramic. Here, the polyimide layer may partially cover the substrate layer or the surface of the substrate. As a production method, a polyimide film is produced from a polyimide precursor and bonded to the base layer or the base, or a polyimide precursor solution is applied to at least a part of the surface of the base layer or the base, Into a laminate. Since the polyimide precursor of the present invention can easily produce a polyimide having excellent properties, it is possible to produce a heat-resistant electric wire insulating layer, a substrate for a display, a substrate for a touch panel, a substrate for a solar cell, a substrate for a thin-film semiconductor, a sliding part. In the production of flexible circuit boards.

<< Part II >>
The invention of Part II is to provide a polyimide precursor which can easily produce a polyimide having a suitably high crosslinking density, a crosslinked polyimide which is excellent in heat resistance, dimensional stability at high temperature, and excellent bending resistance, and a method for producing the same. With the goal.

  The present inventors have conducted intensive studies and as a result, by using a combination of a specific tetracarboxylic acid ester compound and a specific compound having three or more amino groups, a polyimide having a crosslink density suitable for films and coatings is produced. A possible polyimide precursor was found, and the invention of Part II was completed.

That is, the invention of Part II relates to the following matters.

1. At least,
A tetracarboxylic ester derivative (A) selected from the compounds represented by the general formula (II-1),
Amine compound (B) having three or more amino groups selected from compounds represented by general formula (II-3)
A polyimide precursor comprising:

〔式中のＸ_１は直接結合もしくは、下記式（ＩＩ−２）で示される基から選ばれる２価の基を表し、Ｒ_１１〜Ｒ_３０は、それぞれ独立に水素、炭素数１〜８の１価の脂肪族基（ただし、テトラカルボン酸となる場合を除く）を表す。〕

[In the formula, X ₁ represents a direct bond or a divalent group selected from groups represented by the following formula (II-2), and R _{11 to} R ₃₀ each independently represent hydrogen or C 1-8. It represents a monovalent aliphatic group (except when it becomes tetracarboxylic acid). ]

〔式中のＸ_２は、２価の有機基である。〕

[X ₂ in the formula is a divalent organic group. ]

〔Ｚ_１は３価の窒素原子、３価以上の芳香族基、３価以上の脂肪族基、Ｚ_２およびＺ_３は直接結合または２価の基であり、Ｒ_３１〜Ｒ_３６は１価の芳香族基、脂肪族基、ハロゲン、ｎ_１は３以上、ｍ_１およびｍ_３は０〜４、ｍ_２およびｍ_４〜ｍ_６は０〜３の整数を表す。〕
２． さらに、ジアミン（Ｃ）を含むことを特徴とする上記１に記載のポリイミド前駆体。

[Z ₁ is a trivalent nitrogen atom, a trivalent or higher aromatic group, a trivalent or higher aliphatic group, Z ₂ and Z ₃ are a direct bond or a divalent group, and R _{31 to} R ₃₆ are monovalent. aromatic group, an aliphatic group, a halogen, _{n 1} is 3 or more, _{m 1} and _{m 3} is 0 to 4, _{m 2} and _m 4 ~m ₆ represents an integer of 0 to 3. ]
2. The polyimide precursor according to the above item 1, further comprising a diamine (C).

  3. 3. The polyimide precursor according to the above 2, wherein the proportion of the amine compound (B) represented by the following formula is in the range of 0.01 to 1.

[Total mole number of the amine compound (B)] / ([Total mole number of the amine compound (B)] + [Total mole number of the diamine (C)])
4. The polyimide precursor according to any one of the above items 1 to 3, wherein the molecular weight α between crosslinking points when the polyimide is formed is in the range of 500 to 10,000 g / mol.

  5. 4. The polyimide precursor according to the above item 2 or 3, wherein the diamine (C) contains at least one kind selected from the compounds represented by the general formula (II-4).

〔式中のＹ_１は直接結合または２価の基を表し、Ｒ_４１〜Ｒ_４３はそれぞれ独立に１価の芳香族基、脂肪族基、ハロゲンを表し、ｍ_５〜ｍ_７は０〜４の整数を表す。〕
６． 上記１〜５のいずれか１項に記載のポリイミド前駆体と、溶媒（Ｄ）を含むことを特徴とするポリイミド前駆体溶液。

[Wherein Y ₁ represents a direct bond or a divalent group, R _{41 to} R ₄₃ each independently represent a monovalent aromatic group, an aliphatic group, or a halogen, and m _{5 to} m ₇ represent 0 to 4 Represents an integer. ]
6. A polyimide precursor solution, comprising: the polyimide precursor according to any one of the above items 1 to 5; and a solvent (D).

  7. A polyimide precursor solution for producing a film, comprising the polyimide precursor according to any one of the above 1 to 5.

  8. A paint for forming a polyimide coating film, comprising the polyimide precursor according to any one of the above 1 to 5.

  9. 6. A method for producing a polyimide, comprising imidizing the polyimide precursor according to any one of the above 1 to 5 to produce a polyimide having a crosslinked structure.

10. A polyimide having a structural unit derived from a tetracarboxylic acid component and a structural unit derived from an amine component,
Structural units derived from the amine component are structural units derived from an amine compound (Bi) having three or more amino groups and a diamine (Ci), respectively, in a range where the value of the following formula is 0.01 to 1. A polyimide having a crosslinked structure, characterized by being included in

[Total moles of amine compound (Bi)] / ([Total moles of amine compound (Bi)] + [Total moles of diamine (Ci)])
11. The polyimide having a crosslinked structure according to the above item 10, wherein the molecular weight α between crosslink points is in the range of 500 to 10,000 g / mol.

  12. 12. The polyimide having a crosslinked structure according to 10 or 11, wherein the glass transition temperature of the polyimide having a crosslinked structure is 200 ° C. or higher.

  13. 13. The polyimide having a crosslinked structure according to any one of the above items 10 to 12, wherein an average linear expansion coefficient at 50 ° C. to 200 ° C. when measured on a film having a thickness of 10 μm is 60 ppm / K or less.

  14． 14. The polyimide having a crosslinked structure according to any one of the above items 10 to 13, wherein the 5% weight loss temperature determined by TGA is 430 ° C. or higher.

  15. 15. A film comprising the polyimide having a crosslinked structure according to any one of 10 to 14 above.

  16. A laminate comprising any one of a glass layer, a metal layer, a resin layer, and a ceramic layer, and the polyimide having a crosslinked structure according to any one of the above 10 to 14.

<Effect of the invention of Part II>
By using the polyimide precursor of the invention of Part II, a polyimide having a crosslinking density suitable for a film or a coating film can be produced. By using the polyimide having a crosslinked structure according to the invention of Part II, a polyimide having excellent heat resistance, dimensional stability at high temperatures, and bending resistance can be provided. Further, by using these for a film or the like, a film having excellent heat resistance, dimensional stability at high temperature, and bending resistance can be provided.

<Details of the invention of Part II>
In the description of the invention of Part II, the tetracarboxylic acid ester derivative (A) selected from the compounds represented by the general formula (II-1) is simply referred to as “tetracarboxylic acid ester derivative (A)” or the general formula (II). The amine compound (B) (triamine compound, tetraamine compound, etc.) having three or more amino groups selected from the compounds represented by -3) may be simply referred to as "amine compound (B)".

(Polyimide precursor)
The polyimide precursor of the invention of Part II is a polyimide precursor that forms a polyimide by a chemical reaction, and includes at least the tetracarboxylic acid ester derivative (A) and the amine compound (B) as described above.

  The tetracarboxylic acid ester derivative (A) is selected from compounds represented by the following general formula (II-1).

In the formula, X ₁ represents a direct bond or a divalent organic group selected from the group represented by the following formula (II-2), and R _{11 to} R ₃₀ each independently represent hydrogen or a C 1 to C 8 group. It represents a monovalent aliphatic group (except when it becomes tetracarboxylic acid).

X ₂ in the formula represents a divalent organic group. It is preferably a divalent organic group having an aromatic ring or an alicyclic structure, and more preferably a general formula:

R _{111 to} R ₁₂₄ are directly bonded, and

からなる群より選ばれる基である。

A group selected from the group consisting of

  In order to obtain a polyimide having a crosslinking density suitable for a film or a coating film, the tetracarboxylic acid ester derivative (A) used preferably does not have a ketone bond in the molecular structure. For example, when a benzophenone tetracarboxylic acid ester compound is used, the film-forming property is inferior, and it becomes difficult to produce a film (see Examples).

  Specific examples of the tetracarboxylic acid ester derivative (A) include the ester derivatives of those exemplified as the tetracarboxylic acid (a) in Part I, and more preferably 3,3 ′, 4,4′-biphenyltetracarboxylic acid. It is an ester derivative such as carboxylic acid, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, pyromellitic acid, oxydiphthalic acid, and 4,4 ′-(2,2-hexafluoroisopropylene) diphthalic acid.

  Use of ester derivatives such as 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2,3,3', 4'-biphenyltetracarboxylic acid, and pyromellitic acid provides excellent heat resistance and dimensional stability. It is preferable to use an ester derivative such as 4,4′-oxydiphthalic acid or 4,4 ′-(2,2-hexafluoroisopropylene) diphthalic acid because solubility and polyimide coloring can be reduced.

  Further, as these tetracarboxylic acid ester derivatives, any of monoester, diester, triester, and tetraester derivative can be suitably used, but diester derivatives and tetraester derivatives are preferable because they can be easily produced, and Diester derivatives are more preferred because of their excellent reactivity.

Further, in the general formula _(II-1), the monovalent aliphatic group which R 11 _{to R 30} can be taken 1 to 8 carbon atoms, preferably an alkyl of 1 to 3 carbon atoms, particularly 1 to 3 carbon atoms N-alkyl is preferred.

  The amine compound (B) has three or more amino groups and is selected from compounds represented by the general formula (II-3).

In the formula, Z ₁ is a trivalent nitrogen atom (N), a trivalent or higher aromatic group which may have a hetero atom in the ring member, or a trivalent or higher aliphatic which may have a hetero atom. represents a family group, _{Z 2} and _{Z 3} is a direct bond or a divalent _group, a monovalent aromatic radical R 31 _{to R 36} each independently represent an aliphatic group, a halogen, _{n 1} is, Z _{It is} a valence of ₁ and represents an integer of 3 or more, preferably 6 or less, more preferably an integer of 3 or 4, m ₁ and m ₃ are 0 to 4, m ₂ and m _{4 to} m ₆ are 0. Represents an integer of 1 to 3.

Although not particularly limited, Z ₁ in the general formula (II-3) is preferably a trivalent or higher valent group represented by the general formula (II-5).

R _{51 to} R ₁₀₀ in the formula each independently represent a direct bond or one of divalent groups represented by the following formula (II-6), and R ₁₀₁ represents hydrogen or an aliphatic group or an aromatic group. (Both preferably up to about 18 carbon atoms).

R _{51 to} R ₅₃ are a direct bond or a compound represented by the formula:

で示される基から選ばれることが好ましい。

It is preferable to be selected from the groups represented by

Although not particularly limited, Z ₂ and Z ₃ in the general formula (II-3) are preferably a direct bond or any divalent group represented by the above formula (II-6), Among them, from the viewpoint of excellent heat resistance, a direct bond, an ether bond, an ester bond, an amide bond, an isopropylidene bond, and a hexafluoroisopropylidene bond are more preferable, and a direct bond and an ether bond are particularly preferable.

R _{31 to} R ₃₆ in the formula (II-3) include an aromatic group having 12 or less carbon atoms (for example, a phenyl group, a benzyl group, and a phenoxy group), an alkyl group having 1 to 6 carbon atoms, fluorine, and chlorine. Is preferred.

m ₁ is preferably 0, 1 or 2, m ₂ is preferably 0 or 1, m ₃ is preferably 0, 1 or 2, m ₄ is preferably 0 or 1, m ₅ and m ₆ are independently preferred Is 0 or 1.

  Since the amine compound (B) has excellent reactivity, the ring bonded to the amino group in the chemical structure is preferably a heterocyclic ring or an aromatic ring having no quinone structure, and a tetracarboxylic acid derivative It is more preferable that the chemical structure does not include a hydroxyl group, a thiol, or a secondary amine in order to suppress side reactions other than the imidation reaction.

  Specific examples of the amine compound (B) include those exemplified as the amine compound (B) in Part I, and preferred examples are also the same, and a single compound or a mixture of two or more compounds may be used. The point is the same.

  The polyimide precursor of the invention of Part II can optionally contain a diamine (C). Although not particularly limited, it is preferable that the diamine (C) include at least one or more of any of the compounds represented by the general formula (II-4) because of excellent heat resistance.

In the formula, Y ₁ represents a direct bond or a divalent group, R _{41 to} R ₄₃ each independently represent a monovalent aromatic group, an aliphatic group, or a halogen group, and m _{5 to} m ₇ represent 0 to 4 Represents an integer.

Although not particularly limited, Y ₁ in the general formula (II-4) is a group represented by the above formula (II-6) or a divalent group represented by the following general formula (II-7) It is preferable to be selected from

In the formula, R _{111 to} R ₁₂₄ each independently represent a direct bond or a divalent group represented by the above formula (II-6). As R _{111 to} R ₁₂₄ , a direct bond, an ether bond, an ester bond, an amide bond, an isopropylidene bond, and a hexafluoroisopropylidene bond are more preferable because of excellent heat resistance, and a direct bond and an ether bond are particularly preferable. preferable.

As Y ₁ , since it has excellent heat resistance, it can be a direct bond, an ether bond, an ester bond, an amide bond, an isopropylidene bond, a hexafluoroisopropylidene bond, or any of R _{111 to} R among groups represented by the formula (II-7). Preferably, ₁₂₄ is a group selected from a direct bond, an ether bond, an ester bond, an amide bond, an isopropylidene bond and a hexafluoroisopropylidene bond.

R _{41 to} R ₄₃ are preferably an aromatic group having 12 or less carbon atoms (for example, a phenyl group, a benzyl group, or a phenoxy group), an alkyl group having 1 to 6 carbon atoms, fluorine, or chlorine.

m _{5 to} m ₇ are preferably 0, 1 or 2.

  Specific examples of the diamine (C) include those exemplified as the diamine (C) in Part I, and preferred examples are also the same, and the diamine (C) may be used alone or in combination of two or more. Is the same.

  In the polyimide precursor of the invention of Part II, the value of [total moles of amine compound (B)] / ([total moles of amine compound (B)] + [total moles of diamine (C)]) is as follows: Although not particularly limited, it is 0.01 to 1, preferably 0.05 to 1, more preferably 0.2 to 1, still more preferably 0.25 to 1, and particularly preferably 0.5 to 1. is there. Within this range, the polyimide has excellent dimensional stability at high temperatures and excellent bending resistance.

  The polyimide precursor of the invention of Part II is not particularly limited, but the number of carboxylic acid groups (including the number of esterified carboxylic acid groups) of the tetracarboxylic acid component (the number of moles) / total amine of the amine component The value of the number of groups (number of moles) is preferably from 1 to 3, more preferably from 1.6 to 2.4, still more preferably from 1.8 to 2.2, and particularly preferably substantially 2. Within this range, heat resistance, dimensional stability at high temperatures, and solvent resistance are excellent.

  In the polyimide precursor of the invention of Part II, the molecular weight α between crosslink points when a polyimide is formed is preferably in the range of 500 to 100,000 g / mol, more preferably in the range of 1,300 to 10,000. , More preferably from 1,500 to 5,000, particularly preferably from 1,800 to 4,000. The molecular weight α between cross-linking points has a substantially positive correlation with the elongation of the resin, and a substantially negative correlation with the elasticity of the resin, so that within this range, high elongation, high elasticity, bending resistance, and high temperature Dimensional stability can be compatible.

  Here, as described in Part I, the molecular weight α between cross-linking points can be obtained as a theoretical value by Expression (6) or from an experimental value by Expression (7).

  The molecular weight α between crosslink points of the invention of Part II is not particularly limited, but when a raw material having a ketone bond is used in the invention of Part II, polyimide may cause additional crosslink formation, When a functional group that causes additional cross-linking, such as a ketone bond, is not contained, the value determined from the above formula (6) can be suitably adopted.

  The average molecular weight of the polyimide precursor of the invention of Part II is not particularly limited, but is substantially 50 to 5,000, more preferably 100 to 2,000 because it is substantially composed of a low molecular compound. , 200 to 1,000 are particularly preferred. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained. The molecular weight here may be a number average molecular weight determined by GPC measurement, a molecular weight determined from TOF-MASS, FAB-MASS, or a value of another known analysis method. Further, under the condition that polymerization does not substantially occur, the average molecular weight of each component forming the polyimide can be suitably adopted.

  The logarithmic viscosity (ηinh) of the polyimide precursor of the invention of Part II is substantially less than 0.2, preferably less than 0.15, more preferably less than 0.1 because it is composed of a low molecular weight compound. is there. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained.

  Since the polyimide precursor of the invention of Part II is substantially composed of a low molecular compound, it is preferable that the polyimide precursor does not contain a repeating unit of polyamic acid. For the confirmation of the repeating unit of the polyamic acid, a known analysis method such as NMR or FT-IR can be suitably used. The ratio of the repeating unit (mol) of the polyamic acid is preferably 0.05 mol / mol or less per total mol of amino groups of the amine component (or 1/2 times the total mol of carbonyl groups of the tetracarboxylic acid component). It is at most 0.03 mol / mol, more preferably at most 0.01 mol / mol, particularly preferably at most the detection lower limit. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained.

  The polyimide precursor of the invention of Part II may be a powder, preferably an average particle diameter of 5 mm or less, more preferably 1 mm or less, particularly preferably 0.5 mm or less, and a maximum particle diameter of 5 mm or less, more preferably 1 mm or less. Or less, particularly preferably 0.5 mm or less. These particle diameters can be obtained by using a known measurement method such as a laser diffraction method, an image imaging method, or a gravity sedimentation method, and using a result obtained by using a known analysis method.

(Polyimide precursor solution)
The polyimide precursor solution of the invention of Part II was described collectively in Part I.

(Polyimide having a crosslinked structure)
The polyimide having a crosslinked structure of the invention of Part II is a polyimide having a structural unit derived from a tetracarboxylic acid component and a structural unit derived from an amine component, and the structural unit derived from the amine component has three or more structural units. Structural units derived from the amine compound (Bi) and the diamine (Ci) each having an amino group are included in a range where the value of the following formula is 0.01 to 1.

  [Total moles of amine compound (Bi)] / ([Total moles of amine compound (Bi)] + [Total moles of diamine (Ci)])

  Here, the value of the formula, [total mole number of amine compound (Bi)] / ([total mole number of amine compound (Bi)] + [total mole number of diamine (Ci) component]) is preferably 0.1. 05 to 1, more preferably 0.2 to 1, still more preferably 0.25 to 1, particularly preferably 0.5 to 1. Within this range, a high crosslinking density can be achieved, so that the polyimide has high dimensional stability at high temperature, high bending resistance, high glass transition temperature, and excellent dimensional stability.

  The polyimide having a crosslinked structure of the invention of Part II is not particularly limited, but is preferably produced by the above-mentioned polyimide precursor. Therefore, the tetracarboxylic acid component is preferably a tetracarboxylic acid ester derivative (A) represented by the general formula (II-1). Similarly, the amine compound (Bi) having three or more amino groups is preferably the above-mentioned amine compound (B), and the diamine (Ci) is preferably the above-described diamine (C).

  The polyimide having a crosslinked structure has a molecular weight α between crosslink points of preferably 500 to 100,000 g / mol, more preferably 1,300 to 10,000, and still more preferably 1,500 to 5,5. 000, particularly preferably 1,800-4,000. Within this range, dimensional stability at high temperatures and bending resistance are excellent.

  The polyimide having a crosslinked structure of the invention of Part II is not particularly limited, but from the viewpoint of dimensional stability, the glass transition temperature is 200 ° C or higher, preferably 230 ° C or higher, more preferably 260 ° C or higher, It is more preferably at least 280 ° C, particularly preferably at least 290 ° C. Within this range, dimensional stability is excellent.

  On the other hand, the polyimide having a crosslinked structure of the invention of Part II can be used at a high temperature even with a polyimide having a relatively low glass transition temperature because the deformation at the time of heating is small. , 180 ° C to 300 ° C, more preferably 180 ° C to 260 ° C, even more preferably 180 ° C to 240 ° C, and particularly preferably 180 ° C to 230 ° C. Measurement of the glass transition temperature was described in Part I.

  In Part I, the linear expansion coefficient of polyimide having a crosslinked structure, 5% weight loss temperature, solvent resistance, total light transmittance when the film thickness is 10 μm, a film, and a laminate are described in Part 1 of the invention. The same is true for polyimide having a structure.

(Method for producing polyimide having a crosslinked structure)
The method for producing a polyimide by imidizing the polyimide precursor of the invention of Part II is not particularly limited, and a known polyimide production method can be appropriately employed. Except for using the polyimide precursor described in Part II as the polyimide precursor, for example, a polyimide can be produced by the method described in the section of “(Method for Producing Polyimide Having Cross-Linked Structure)” in Part I.

(Use of polyimide precursor, laminate, and method for producing the same)
The polyimide precursor of the invention in Part II can be used for the applications described in Part I, “Items for (Applications of Polyimide Precursors, Laminates, and Methods for Producing the Same)”.

<< Part III >>
The purpose of the invention of Part III is to provide a polyimide precursor mainly comprising a combination of s-BPTA or a derivative thereof and a diamine having a para-positioned aromatic ring, and giving a polyimide having high heat resistance.

  The present inventors have conducted intensive studies and as a result, using a specific tetracarboxylic acid in a polyimide comprising a combination of s-BPTA giving high heat resistance and a diamine having an aromatic ring having a para-position, By using an amine compound having a cyclic structure in the molecular structure, a high-quality polyimide was found to be obtained, and the invention of Part III was completed.

  That is, the invention of Part III relates to the following matters.

1. At least one tetracarboxylic acid (A31) selected from 3,3 ′, 4,4′-biphenyltetracarboxylic acid and ester derivatives thereof,
A tetracarboxylic acid component containing at least one tetracarboxylic acid (A32) selected from the tetracarboxylic acids different from the tetracarboxylic acids (A31) and ester derivatives thereof;
A polyimide precursor comprising a diamine component containing an aromatic ring diamine (B31) represented by the following general formula (III-1).

〔式中のＹ_１は直接結合、エーテル結合、エステル結合、アミド結合、ケトン結合、メチレン、イソプロピリデン、ジメチルシリレンまたは、炭素数１〜６のアルキレン、炭素数１２以下の芳香族基、または下記一般式（ＩＩＩ−２）で表されるいずれかの分子構造を表し、Ｒ_１〜Ｒ_３は、それぞれ独立に炭素数１２以下の芳香族基、炭素数１〜６のアルキル基、ハロゲン基、水酸基、カルボン酸基であり、ｎ_１〜ｎ_３は０〜４の整数を表す。〕

[Y ₁ in the formula is a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene or an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, or Represents any molecular structure represented by the general formula (III-2), and R _{1 to} R ₃ each independently represent an aromatic group having 12 or less carbon atoms, an alkyl group having 1 to 6 carbon atoms, a halogen group, It is a hydroxyl group or a carboxylic acid group, and n _{1 to} n ₃ represent an integer of 0 to 4. ]

〔式中のＹ_２は直接結合、エーテル結合、エステル結合、アミド結合、ケトン結合、メチレン、イソプロピリデン、ジメチルシリレンまたは、炭素数１〜６のアルキレン、炭素数１２以下の芳香族基を表し、Ｒ_４、Ｒ_５は、それぞれ独立に炭素数１〜６のアルキレン、炭素数１２以下の芳香族基を表す。〕

[Y ₂ in the formula represents a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene, or an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, R ₄ and R ₅ each independently represent an alkylene having 1 to 6 carbon atoms or an aromatic group having 12 or less carbon atoms. ]

2. The polyimide precursor according to the above item 1, wherein the tetracarboxylic acid (A32) contains at least one kind of a tetracarboxylic acid represented by the general formula (III-3) and an ester derivative thereof.

〔式中のＸ_１は、直接結合または、２価の基である。ただし、Ｘ_１が直接結合の場合は、３，３’，４，４’−ビフェニルテトラカルボン酸を除く。〕

[X ₁ in the formula is a direct bond or a divalent group. However, when X ₁ is a direct bond, 3,3 ′, 4,4′-biphenyltetracarboxylic acid is excluded. ]

3. The tetracarboxylic acid (A32) is, pyromellitic acid and ester derivatives thereof, as well as X ₁ in the general formula (III-3), a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene Ridene, hexafluoroisopropylidene, dimethylsilylene, an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, or a tetracarboxylic acid represented by any of the general formula (III-4) and ester derivatives thereof 3. The polyimide precursor according to any one of the above 1 or 2, wherein the polyimide precursor comprises at least one member selected from the group consisting of:

〔式中のＸ_２は、２価の有機基である。〕

[X ₂ in the formula is a divalent organic group. ]

4. 4. The polyimide precursor according to any one of the above items 1 to 3, wherein the tetracarboxylic acid component contains 50 mol% or more of a tetracarboxylic acid (A31) based on a total molar amount of all tetracarboxylic acid components. body.

5. Wherein the diamine component is a diamine different from the diamine (B31), and includes one or more diamines (B32) selected from the compounds represented by the general formula (III-5). 5. The polyimide precursor according to any one of 4.

〔式中のＹ_３は直接結合または２価の基を表し、Ｒ_６〜Ｒ_８は、それぞれ独立に炭素数１２以下の芳香族基、炭素数１〜６のアルキル基、ハロゲン基、水酸基、カルボン酸基であり、ｎ_４〜ｎ_６は０〜４の整数を表す。ただし、前記一般式（ＩＩＩ−１）で表されるジアミンを除く。〕

[Wherein Y ₃ represents a direct bond or a divalent group, and R _{6 to} R ₈ each independently represent an aromatic group having 12 or less carbon atoms, an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, It is a carboxylic acid group, and n _{4 to} n ₆ represent an integer of 0 to 4. However, the diamine represented by the general formula (III-1) is excluded. ]

6. The polyimide precursor according to any one of the above items 1 to 5, wherein the diamine component contains the diamine (B31) in an amount of 50 mol% or more based on the total molar amount of all diamine components.

7. 7. The polyimide precursor according to any one of the above items 1 to 6, further comprising an amine compound (G) having a cyclic structure in the molecule.

8. The polyimide precursor according to the above item 7, wherein the amine compound (G) is selected from the group consisting of an aliphatic amine having a cyclic structure, an aromatic amine, and a heterocyclic amine.

9. The polyimide precursor according to the above item 7 or 8, wherein the amine compound (G) contains nitrogen as a ring member atom.

10. The polyimide precursor according to any one of the above items 7 to 9, wherein the amine compound (G) has a pyridine, pyrimidine, triazole or imidazole skeleton.

11. The polyimide precursor according to any one of the above items 7 to 10, wherein the amine compound (G) is contained in an amount of 10 mol% or more based on the total molar amount of all tetracarboxylic acid components.

12. 12. The polyimide precursor according to any one of the above items 1 to 11, further comprising a compound (H) having at least one kind of three or more amino groups.

13. 13. The polyimide precursor according to any one of the above items 1 to 12, which is a powder having a particle diameter of 5 mm or less.

14． 13. A polyimide precursor solution, comprising: the polyimide precursor according to any one of the above items 1 to 12; and a solvent (D).

15. 15. The polyimide precursor solution according to the above 14, further comprising inorganic particles (E).

16. Using the polyimide precursor according to any one of the above 1 to 12, or the polyimide precursor solution according to any one of the above 13 to 15 to imidize the polyimide precursor, the glass transition temperature is 250 ℃ A method for producing a polyimide, comprising producing the above polyimide.

17． Using the polyimide precursor according to any one of the above 1 to 12, or the polyimide precursor solution according to any one of the above 13 to 15, the polyimide precursor is imidized, and a film having a film thickness of 10 μm. A method for producing a polyimide, comprising producing a polyimide having an average coefficient of linear expansion at 50 ° C. to 200 ° C. as measured at 60 ppm / K or less.

18. The polyimide precursor according to any one of the above 1 to 12, or the polyimide precursor solution according to any one of the above 13 to 15, the polyimide precursor was imidized, and 5% obtained by TGA. A method for producing a polyimide, comprising producing a polyimide having a weight reduction temperature of 450 ° C. or higher.

19. Using the polyimide precursor according to any one of the above 1 to 12, or the polyimide precursor solution according to any one of the above 13 to 15, the polyimide precursor is imidized, and the stress-strain of the tensile test is performed. A method for producing a polyimide, comprising producing a polyimide having an initial elastic modulus obtained from a curve of 2.5 GPa or more.

20. Using the polyimide precursor according to any one of the above 1 to 12 or the polyimide precursor solution according to any one of the above 13 to 15, a polyimide layer and a glass, a metal, a resin, or a ceramic. Producing a polyimide laminate in which at least one material layer or substrate is laminated.

21. The polyimide precursor according to any one of the above 1 to 12, or the polyimide layer obtained from the polyimide precursor solution according to any one of the above 13 to 15, and a glass, a metal, a resin, or a ceramic. A polyimide laminate in which at least one layer or substrate is laminated.

22. Using the polyimide precursor according to any one of the above 1 to 12, or the polyimide precursor solution according to any one of the above 13 to 15, a heat-resistant wire insulating layer, a sliding component, a flexible circuit board, Alternatively, a method for producing a substrate selected from a display substrate, a touch panel substrate, a solar cell substrate, and a thin film semiconductor substrate.

  <Effect of the invention of Part III>

  According to the invention of Part III, it is possible to provide a polyimide precursor capable of easily producing a high heat-resistant polyimide, and a method for producing the same. In addition, the polyimide precursor solution of the invention of Part III is excellent in solubility, is capable of high solid differentiation, and is excellent in storage stability. Furthermore, the polyimide obtained from the polyimide precursor of the invention of Part III is excellent in film-forming properties, can form a high-quality film having bendability, and has a higher mechanical strength (compared to polyimide obtained from conventional polyamic acid). (E.g., high modulus of elasticity, stress at yield, stress at break) and low coefficient of linear expansion.

<Details of Invention of Part III>
(Polyimide precursor)
As described above, the invention of Part III includes, as a tetracarboxylic acid component, at least one tetracarboxylic acid (A31) selected from 3,3 ′, 4,4′-biphenyltetracarboxylic acid and an ester derivative thereof, An aromatic ring diamine containing a tetracarboxylic acid (A31) and at least one tetracarboxylic acid (A32) selected from different tetracarboxylic acids and ester derivatives thereof, and represented by the general formula (III-1) as a diamine component: It is a polyimide precursor containing (B31). The tetracarboxylic acid (A31) and the tetracarboxylic acid (A32) are described as "acids", and each includes an ester derivative as defined. The definition and state of the “polyimide precursor” are as described at the beginning.

  The tetracarboxylic acid (A31) is not limited as long as it is selected from 3,3 ', 4,4'-biphenyltetracarboxylic acid and its ester derivative. In one embodiment, 3,3 ', 4,4'-biphenyltetracarboxylic acid is preferred because the only component eliminated is water. On the other hand, in different embodiments, ester derivatives are preferred because of their excellent solubility. In this case, four carboxylic acid groups may be esterified, or only a part thereof may be esterified. In one embodiment, it is preferred that two of the four carboxylic acids of the tetracarboxylic acid are esterified. As the compound providing an ester group, an alcohol having 1 to 3 carbon atoms, a phenol having 6 to 12 carbon atoms, and a silanol having 3 to 12 carbon atoms are preferable.

  Diamine (B31) is an aromatic diamine (B31) selected from the compounds represented by the general formula (III-1).

[Y ₁ in the formula is a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene or an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, or Represents any molecular structure represented by the general formula (III-2), and R _{1 to} R ₃ each independently represent an aromatic group having 12 or less carbon atoms, an alkyl group having 1 to 6 carbon atoms, a halogen group, It is a hydroxyl group or a carboxylic acid group, and n _{1 to} n ₃ represent an integer of 0 to 4. ]

〔式中のＹ_２は直接結合、エーテル結合、エステル結合、アミド結合、ケトン結合、メチレン、イソプロピリデン、ジメチルシリレンまたは、炭素数１〜６のアルキレン、炭素数１２以下の芳香族基を表し、Ｒ_４、Ｒ_５は、それぞれ独立に炭素数１〜６のアルキレン、炭素数１２以下の芳香族基を表す。〕

[Y ₂ in the formula represents a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene, or an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, R ₄ and R ₅ each independently represent an alkylene having 1 to 6 carbon atoms or an aromatic group having 12 or less carbon atoms. ]

Diamine (B31) has a para-bonded aromatic ring and does not contain a functional group (for example, a sulfonic acid group or a trifluoromethane group) which is easily thermally decomposed, and thus is suitable as a main component of a diamine of polyimide. is there. In order to provide a polyimide having heat resistance, mechanical properties, and a low coefficient of linear expansion, a diamine of the formula (1-1) in the formula (III-1) is preferable, and n ₁ is 0, n ₁ is 1 and R ₁ is more preferably having a methyl group, those n ₁ is 0 are particularly preferred. On the other hand, from the viewpoint that the solubility and storage stability of the polyimide precursor solution and the heat resistance, high mechanical strength, and low coefficient of linear expansion of the polyimide are compatible, the diamine of the formula (1-2) is preferable. In particular, Y ₁ in the formula (1-2) is preferably a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, or a methylene, because of high mechanical strength and a low linear expansion coefficient, and more preferably. It is a direct bond, an ether bond, or an amide bond, particularly preferably an ether bond. On the other hand, are represented among the diamine (1-2), the solubility of the polyimide precursor solution, and storage stability, since it is excellent in film properties of the polyimide, Y ₁ is, formula (III-2) It is preferably any one of the molecular structures, more preferably the structures of the formulas (2-2) and (2-3), and particularly preferably, in the formula (2-2), R ₄ and R ₅ are isopropylidene. And (2-3), wherein Y ₂ is isopropylidene.

  The tetracarboxylic acid (A32) is not limited as long as it is a tetracarboxylic acid and its ester derivative other than 3,3 ', 4,4'-biphenyltetracarboxylic acid and its ester derivative. Since the solubility and storage stability of the polyimide precursor solution and the film-forming property and heat resistance of the polyimide can be compatible, any of the tetracarboxylic acids represented by the general formula (III-3) or ester derivatives thereof can be used. preferable.

[X ₁ in the formula is a direct bond or a divalent group. However, when X ₁ is a direct bond, 3,3 ′, 4,4′-biphenyltetracarboxylic acid is excluded. ]

Furthermore, since the solubility and storage stability of the polyimide precursor solution and the film forming property, heat resistance, high mechanical strength, and low linear expansion coefficient of polyimide can be compatible, pyromellitic acid and its tetracarboxylic acid (A32) can be used. In the ester derivative or the formula (3-2) in the general formula (III-3), X ₁ represents a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, hexafluoroisopropylide Preference is given to lidene, dimethylsilylene, alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, or a tetracarboxylic acid represented by any of the following general formula (III-4) and an ester derivative thereof. .

〔式中のＸ_２は、２価の有機基であり、例えば、直接結合、エーテル結合、エステル結合、アミド結合、ケトン結合、メチレン、イソプロピリデン、ヘキサフルオロイソプロピリデン、ジメチルシリレンおよび炭素数１〜６のアルキレンである。〕

[In the formula, X ₂ is a divalent organic group, and examples thereof include a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, hexafluoroisopropylidene, dimethylsilylene, and a compound having 1 to 1 carbon atoms. 6 alkylene. ]

More preferably, as the tetracarboxylic acid (A32), pyromellitic acid and X _{1 of the} formula (3-2) are a direct bond, an ether bond, an ester bond, a ketone bond, isopropylidene, hexafluoroisopropylidene, dimethylsilylene. And more preferably a tetracarboxylic acid and an ester derivative thereof, wherein X _{1 in} the formula (3-2) is a direct bond or an ether bond, and particularly preferably 2,3. ', 3,4'-biphenyltetracarboxylic acid and its ester derivatives.

  The total ratio of the tetracarboxylic acid (A31) and the tetracarboxylic acid (A32) to the total molar amount of all the tetracarboxylic acid components is preferably 90 mol% or more, more preferably 95 mol% or more, and most preferably. Substantially 100 mol%. The ratio of the tetracarboxylic acid (A31) is preferably at least 50 mol%, more preferably at least 50 mol%, based on the total molar amount of all the tetracarboxylic acid components, since the obtained polyimide has excellent heat resistance, mechanical strength and low linear expansion coefficient. It is at least 75 mol%, more preferably at least 80 mol%, particularly preferably at least 90 mol%. On the other hand, since the polyimide precursor solution is excellent in solubility and storage stability, the ratio of the tetracarboxylic acid (A31) to the total molar amount of all the tetracarboxylic acid components is preferably 95 mol% or less, more preferably 90 mol% or less. Mol% or less, more preferably 85 mol% or less, particularly preferably 80 mol% or less. In this case, the proportion of the tetracarboxylic acid (A32) is preferably at least 5 mol%, more preferably at least 10 mol%, still more preferably at least 15 mol%, particularly preferably at least 5 mol%, based on the total molar amount of all tetracarboxylic acid components. 20 mol% or more.

  As the diamine component, a diamine (B32) represented by the following general formula (III-5) can be used in addition to the aromatic ring diamine (B31) represented by the general formula (III-1).

〔式中のＹ_３は直接結合または２価の基を表し、Ｒ_６〜Ｒ_８は、それぞれ独立に炭素数１２以下の芳香族基、炭素数１〜６のアルキル基、ハロゲン基、水酸基、カルボン酸基、トリフルオロメチル基であり、ｎ_４〜ｎ_６は０〜４の整数を表す。ただし、前記一般式（ＩＩＩ−１）で表されるジアミンを除く。〕

[Wherein Y ₃ represents a direct bond or a divalent group, and R _{6 to} R ₈ each independently represent an aromatic group having 12 or less carbon atoms, an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, It is a carboxylic acid group or a trifluoromethyl group, and n _{4 to} n ₆ represent an integer of 0 to 4. However, the diamine represented by the general formula (III-1) is excluded. ]

Although not particularly limited, Y ₃ includes a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene, or an alkylene having 1 to 6 carbon atoms, and 12 or less carbon atoms. Or a molecular structure represented by any of the above formulas (III-2). Examples of the diamine (B32) include, among those mentioned as the diamine (C) in Part I, compounds not included in the general formula (III-1).

Solubility of the polyimide precursor solution, and storage stability, film-forming properties of the polyimide, because it can achieve both heat resistance, a compound of formula (5-1), or Y ₃ of the formula (5-2), a direct bond, Compounds having an ether bond, an amide bond, or an aromatic group having 12 or less carbon atoms are preferable. Further, since the compound has low linear expansion and excellent mechanical properties, the compound of the formula (5-1) or the compound of the formula (5-2) Compounds in which ₃ is a direct bond or an ether bond are more preferred.

  The total ratio of the diamine (B31) and the diamine (B32) is preferably at least 90 mol%, more preferably at least 95 mol%, most preferably substantially 100 mol%, based on the total molar amount of all diamine components. It is. Since the obtained polyimide has excellent heat resistance, mechanical strength, and low linear expansion coefficient, the proportion of the diamine (B31) having a para-bonded aromatic ring is preferably 50 mol% based on the total molar amount of all diamine components. It is at least 75 mol%, more preferably at least 80 mol%, particularly preferably at least 90 mol%, and preferably at least 100 mol%. On the other hand, from the viewpoint of excellent solubility and storage stability of the polyimide precursor solution, the ratio of the diamine (B32) may be more than 0 mol%, preferably 5 mol% or more, more preferably 10 mol% or more, and still more preferably. It may be 15 mol% or more, particularly preferably 20 mol% or more. In this case, the proportion of the diamine (B31) having a para-bonded aromatic ring is less than 100 mol%, preferably 95 mol% or less, more preferably 90 mol% or less, still more preferably 85 mol% or less, and particularly preferably 80 mol% or less. Mol% or less.

  Furthermore, although not particularly limited, an amine compound (G) having a cyclic structure in the molecule can be added to the polyimide precursor of the invention of Part III. It is preferable to use any of an aliphatic amine, an aromatic amine, and a heterocyclic amine having a cyclic structure, because the polyimide precursor solution has excellent solubility and storage stability and excellent polyimide film-forming properties. Further, an aromatic heterocyclic compound and an aliphatic heterocyclic compound containing a nitrogen atom as a ring atom are more preferable because the obtained polyimide has low coloring.

  Examples of the aromatic heterocyclic compound include pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, isoquinoline, quinazoline, phthalazine, or pyrrole, imidazole, pyrazole, oxazole, isoxazole, indole, and a compound having a benzimidazole skeleton. Here, part of the aromatic heterocyclic structure may be hydrogenated, may have a structure condensed with another ring structure, or may have a substituent in the ring structure . Among these, a compound having a pyridine or imidazole skeleton is preferable, and a compound having an imidazole skeleton is more preferable because the polyimide precursor has excellent solubility and the obtained polyimide has excellent heat resistance and mechanical properties. Examples of the compound having an imidazole skeleton include methylimidazole, dimethylimidazole, and ethyl-methylimidazole. Particularly preferred are 1,2-dimethylimidazole, 1-methylimidazole and the like. Examples of the compound having a pyridine skeleton include pyridine, picoline, dimethylpyridine, vinylpyridine, cyanopyridine, aminopyridine, amino-methylpyridine, (dimethylamino) pyridine, hydroxypyridine, phenylpyridine, quinoline, isoquinoline, viviridine and the like. Can be. Particularly preferred are isoquinoline, picoline, dimethylpyridine and the like.

  Examples of the aliphatic heterocyclic compound include piperidine, piperazine, hexahydropyrimidine, hexahydropyridazine, morpholine, quinuclidine, triethylenediamine (1,4-diazabicyclo [2.2.2] octane), pyrrolidine, tropane, azetidine, aziridine and the like. And a compound having a skeleton of Here, a part of the aliphatic heterocyclic structure may have an unsaturated bond, may have a structure condensed with another ring structure, and may have a substituent in the ring structure. May be. Among these, morpholine, triethylenediamine, diazabicycloundecene, and diazabicyclononene are preferable because the solubility of the polyimide precursor is particularly excellent.

  The content ratio of the amine compound (G) having a cyclic structure is at least 5 mol%, more preferably at least 10 mol%, further preferably at least 20 mol%, particularly preferably at least 10 mol%, based on the total molar amount of all the tetracarboxylic acid components. 30 mol% or more. Further, when the content ratio is 50 mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more, particularly preferably 100 mol% or more, the solubility and storage stability of the polyimide precursor solution are further increased. Excellent. Further, when the content is 150 mol% or more, more preferably 200 mol% or more, the film forming property of polyimide is particularly excellent.

  The polyimide precursor of the invention of Part III may optionally contain a compound (H) having three or more amino groups. As the compound (H) having three or more amino groups, the compounds described as the amine compound (b) in Part I are preferable.

  The average molecular weight of the polyimide precursor of the invention of Part III is not particularly limited, but is substantially 50 to 5,000, more preferably 100 to 2,000 because it is substantially composed of a low molecular compound. , 200 to 1,000 are particularly preferred. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained. The molecular weight here may be a number average molecular weight determined by GPC measurement, a molecular weight determined from TOF-MASS, FAB-MASS, or a value of other known analysis methods. Further, under the condition that polymerization does not substantially occur, the average molecular weight of each component forming the polyimide can be suitably adopted.

  The logarithmic viscosity (ηinh) of the polyimide precursor of the invention of Part III is substantially less than 0.2, preferably less than 0.15, more preferably less than 0.1 because it is composed of a low molecular weight compound. is there. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained.

  Since the polyimide precursor of the invention of Part III is substantially composed of a low molecular compound, it is preferable that the polyimide precursor does not include a repeating unit of polyamic acid. For the confirmation of the repeating unit of the polyamic acid, a known analysis method such as NMR or FT-IR can be suitably used. The ratio of the repeating unit (mol) of the polyamic acid is preferably 0.05 mol / mol or less per total mol of amino groups of the amine component (or 1/2 times the total mol of carbonyl groups of the tetracarboxylic acid component). It is at most 0.03 mol / mol, more preferably at most 0.01 mol / mol, particularly preferably at most the detection lower limit. Within this range, the polyimide precursor has a low molecular weight, and a polyimide precursor solution having both low viscosity and high solid content can be obtained.

  The polyimide precursor of the invention of Part III may be a powder, preferably an average particle diameter of 5 mm or less, more preferably 1 mm or less, particularly preferably 0.5 mm or less, and a maximum particle diameter of 5 mm or less, more preferably 1 mm or less. Or less, particularly preferably 0.5 mm or less. These particle diameters can be obtained by using a known measurement method such as a laser diffraction method, an image imaging method, or a gravity sedimentation method, and using a result obtained by using a known analysis method.

(Polyimide precursor solution)
The polyimide precursor solution of the invention of Part III is as described collectively in Part I.

(Polyimide precursor / inorganic particle composite)
As described in Part I, it is particularly preferable that the polyimide precursor of the invention of Part III is obtained by adding inorganic particles to obtain a polyimide precursor / inorganic particle composite material.

(Polyimide)
The polyimide produced from the polyimide precursor of the invention of Part III includes a tetracarboxylic acid (A31) composed of 3,3 ′, 4,4′-biphenyltetracarboxylic acids and a diamine (B31) having a para-positioned aromatic ring. ) Has a rigid molecular structure based on the combination of Therefore, it has a high glass transition temperature and is not particularly limited, but for example, preferably has a glass transition temperature of 250 ° C. or higher, more preferably 280 ° C. or higher, and still more preferably 300 ° C. or higher.

  Further, the polyimide to be produced has a small thermal expansion, and the average linear thermal expansion coefficient at 50 ° C. to 200 ° C. or the average linear thermal expansion coefficient at 50 ° C. to Tg is preferably 60 ppm / K or less, more preferably 50 ppm / K or less, More preferably, it is 45 ppm / K or less.

  The polyimide produced is excellent in heat resistance, and the 5% weight loss temperature determined by TGA is preferably 450 ° C. or higher, more preferably 470 ° C. or higher, still more preferably 500 ° C. or higher, and particularly preferably 550 ° C. or higher. It is.

  The produced polyimide has a high elastic modulus, and the initial elastic modulus obtained from the stress-strain curve of the tensile test is preferably 2.5 GPa or more, more preferably 3.0 GPa or more, and still more preferably 3.5 GPa or more. And particularly preferably 4.0 GPa or more.

(Method for producing polyimide)
The method for producing polyimide by imidizing the polyimide precursor of the invention of Part III is not particularly limited, and a known polyimide production method can be appropriately employed. Except for using the polyimide precursor described in Part III as the polyimide precursor, for example, a polyimide can be produced by the method described in the section of “(Production Method of Polyimide Having Cross-Linked Structure)” in Part I.

(Use of polyimide precursor, laminate, and method for producing the same)
The polyimide precursor of the invention of Part III can be used for various purposes, for example, for producing a polyimide film, a coating material for producing a polyimide layer in a polyimide laminate, a binder and an adhesive in batteries and other various applications. be able to.

  The polyimide laminate has a structure in which a polyimide layer is laminated with a base layer or a base formed of a material such as glass, metal, resin, or ceramic. Here, the polyimide layer may partially cover the substrate layer or the surface of the substrate. As a production method, a polyimide film is produced from a polyimide precursor and bonded to the base layer or the base, or a polyimide precursor solution is applied to at least a part of the surface of the base layer or the base, Into a laminate.

In the invention of Part III, the solid content concentration in the polyimide precursor solution can be increased, and the storage stability is excellent. Furthermore, the polyimide obtained from the polyimide precursor of the invention of Part III has excellent film-forming properties, can form a high-quality film having bendability, and has a higher mechanical strength than a polyimide obtained from a conventional polyamic acid. (Elastic modulus, yield point stress, break point stress) are high and the coefficient of linear expansion is low. Since the polyimide precursor of the invention of Part III can easily produce a polyimide having excellent properties, it is possible to produce a heat-resistant electric wire insulation layer, a display substrate, a touch panel substrate, a solar cell substrate, a thin film semiconductor substrate, and a slide. It can be suitably used in production of moving parts and production of flexible circuit boards.

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

<< Example of the Invention of Part I >>

The raw materials used in each of the following examples are as follows.
[Tetracarboxylic acid (a)]
3,3 ', 4,4'-biphenyltetracarboxylic acid: s-BPTA
2,3,3 ', 4'-biphenyltetracarboxylic acid: a-BPTA
4,4 '-(4,4'-isopropylidenediphenoxy) bis (phthalic acid): BPABP
4,4 '-(hexafluoroisopropylidene) diphthalic acid: 6FDP
4,4'-oxydiphthalic acid: ODP
3,3 ', 4,4'-benzophenonetetracarboxylic acid: BTTA

[Compound (b) having three or more amino groups]
1,3,5-tris (4-aminophenoxy) benzene: TAPOB

  4,4 ', 4 "-triaminotriphenylamine: TATPA

  2,4,4'-triaminodiphenyl ether: TADE

  2,4,6-triaminopyrimidine: TAP

  1,3,5-tris (4-aminophenyl) benzene: TAPB

[Diamine (C)]
1,3-bis (3-aminophenoxy) benzene: APB
4,4-diaminodiphenyl ether: DADE
2,2'-bis (trifluoromethyl) benzidine: TFMB
m-phenylenediamine: MPD

[Solvent (D)]
N, N-dimethylacetamide: DMAc
N-methyl-2-pyrrolidone: NMP

[Other]
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride: s-BPDA
Glass substrate: 2 mm thick soda glass plate

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

Evaluation of polyimide precursor
[Rotating viscosity]
The viscosity of the polyimide precursor solution at a temperature of 30 ° C. and a shear rate of 100 sec ⁻¹ was determined using a Toki Sangyo TV-22 E-type rotational viscometer.

[Logarithmic viscosity]
The polyimide precursor solution was diluted to 0.5 g / dl with NMP and measured at 30 ° C. using an Ubbelohde viscometer. The logarithmic viscosity (η _inh ) was determined by the following equation.

η _inh = ln (T / T ₀ ) / C
C = concentration of nonvolatile content × amount of composition weighed / volume of sample × 100 (g / dl)
T = falling time of the sample in the viscosity tube, T ₀ = falling speed of N-methyl-2-pyrrolidone Non-volatile content = 350 ° C. × 30 minutes weight after heat treatment / weight before heat treatment (concentration unit: weight%, weight unit: g , Volume unit: dl, time unit: second)

[Varnish solids]
1 g of the polyimide precursor solution was weighed into an aluminum Petri dish and heated in a hot air circulating oven at 200 ° C. for 2 hours to remove non-solid content, and the varnish solid content (heating residue mass%) was determined from the remaining mass. Was.

Evaluation of film forming properties
[Film forming property]
The polyimide precursor solution obtained in each example was coated on the washed glass substrate using a bar coater so that the polyimide film had a thickness of 10 μm. After the substrate was dried at 120 ° C. for 5 minutes, it was heated at 150 ° C. and 200 ° C. for 10 minutes and then at 250 ° C. for 1 hour to thermally imidize it. In the table, 場合 indicates that a transparent and uniform film was obtained, △ indicates that the film was dusty, and X indicates that it was whitened, cracked, or powdery.

Evaluation of polyimide film
[Thermo-mechanical properties (TMA): glass transition temperature, deformation during heating: 1%, 5%, 10% elongation temperature]
A polyimide film having a film thickness of about 10 μm was cut into a strip having a width of 4 mm to obtain a test piece, and the temperature was raised to 475 ° C. at a chuck length of 15 mm, a load of 2 g, and a heating rate of 20 ° C./min using TMA-50 manufactured by Shimadzu Corporation. did. From the obtained TMA curve, the coefficient of linear expansion and the temperature at 1%, 5%, and 10% elongation (° C.) were obtained, and the glass transition temperature (° C.) was obtained from the inflection point. The coefficient of linear expansion was defined as the average coefficient of linear expansion between 50 ° C. and 200 ° C., and when the glass transition temperature was 200 ° C. or less, or near, the average coefficient of linear expansion between 50 ° C. and the starting temperature of the glass transition.

[5% thermal weight loss temperature]
A polyimide film having a film thickness of 10 μm was used as a test piece, and the temperature was increased from 25 ° C. to 600 ° C. at a rate of 10 ° C./min in a nitrogen stream using a differential thermogravimetric simultaneous measurement device (TG / DTA6300) manufactured by SII Nanotechnology. The temperature rose. From the obtained weight curve, a 5% thermal weight loss temperature was determined.

[Bendability]
A polyimide film (thickness: about 10 μm, width: 1 cm, length: 5 cm) was sandwiched between slide glasses and bent (split), and a weight having a weight of 100 g was placed on the bent portion and allowed to stand for 1 minute. The bent portion was returned, and the case where there was no abnormality was evaluated as ○, and the case where cracks or the like occurred was evaluated as ×.

[Solvent resistance]
A polyimide film (about 10 μm thick, 1 cm wide and 1 cm long) was immersed in 10 g of NMP at 25 ° C. for 30 minutes.場合 indicates that there was no abnormality, and X indicates that dissolution or significant swelling was observed.

[Optical characteristics: total light transmittance, light transmittance at 420 nm]
A polyimide film having a film thickness of 10 μm was used as a test piece, and the measurement was performed using a spectrophotometer (V650 manufactured by JASCO Corporation, ARSV-732 absolute reflection unit).

[Hygroscopic resistance]
The polyimide film (thickness: about 10 μm) obtained in each example was treated for one hour under the conditions of 121 ° C. and wet saturation using EHS-411, an advanced accelerated life test manufactured by Espec Corporation. When there was no abnormality, it was evaluated as 、, when some abnormality such as whitening was observed, Δ, and when there was abnormality such as whitening on the entire surface, it was evaluated as ×.

[Example I-1]
As the tetracarboxylic acid (a), s-BPTA (dihydrate) 1.015 molar equivalent (1.291 g), as the compound (b) having three or more amino groups, TAPOB 0.03 molar equivalent (0 0.042 g) and 0.97 molar equivalents (1.000 g) of APB as a diamine (C) were placed in a mortar, ground sufficiently, and mixed to obtain a polyimide precursor powder. When this powder was checked with a microscope, particles having a particle diameter of 0.5 mm or more were not found. To this powder, as a solvent (D), DMAc was added in an amount (9.33 g) to give a monomer concentration of 20% by mass, and dissolved by heating at 50 ° C. to give a polyimide precursor solution (solid content: 20%, viscosity: 50 mPa · s). Obtained.

  The obtained polyimide precursor solution was applied to a glass substrate, dried at 120 ° C. for 5 minutes, and then heated at 150 ° C. and 200 ° C. for 10 minutes each, and then heated at 250 ° C. for 1 hour to thermally imidize. Thus, a polyimide / glass laminate was obtained. Next, the obtained polyimide / glass laminate was immersed in a hot water bath and then peeled off to obtain a polyimide (film) having a film thickness of about 10 μm. The results of measuring the properties of this polyimide are shown in Table I-1.

[Examples I-2 to 24]
A polyimide precursor powder and a solution were prepared in the same manner as in Example I-1, except that the components were changed to those described in Table I-1. In Examples I-23 and I-24, NMP was used as the solvent (D). The obtained polyimide precursor solution was used to obtain a polyimide (film) in the same manner as in Example I-1. The results of measuring the properties of this polyimide are shown in Table I-1.

[Comparative Example I-1]
A polyimide precursor powder and a solution were prepared in the same manner as in Example I-1, except that the components were changed to those described in Table I-1. The obtained polyimide precursor solution was used to obtain a polyimide (film) in the same manner as in Example I-1. The results of measuring the properties of this polyimide are shown in Table I-1.

[Comparative Example I-2]
As the tetracarboxylic acid (a) component, s-BPDA which is a tetracarboxylic dianhydride 1.015 mole equivalent (1.048 g), and as the compound (b) having three or more amino groups, TAPOB 0.03 mole The equivalent (0.042 g) and 0.97 mole equivalent (1.000 g) of APB as the diamine (C) were put in a mortar, ground sufficiently, and mixed to obtain a polyimide precursor powder. DMAc was added to this powder as a solvent (D) in an amount to give a monomer concentration of 20% by mass (8.36 g), and the mixture was heated and stirred at 50 ° C. When the powder was dissolved, the solution viscosity increased and the fluidity was lost (gelation), so that no polyimide precursor solution was obtained.

  Table I-1 summarizes the compositions and evaluation results of the examples and comparative examples. FIG. 1 shows the results of thermomechanical analysis (TMA) of the polyimide obtained in Examples I-2 to I-6 and the polyimide obtained in Comparative Example I-1.

  As can be seen from the results shown in Table I-1, the polyimide precursor of the invention of Part I has a high content of the compound (b) having three or more amino groups in the amine compound of the polyimide precursor. Thus, a precursor solution could be produced, and a crosslinked polyimide could be easily obtained by a thermal method (polycondensation and imidization reaction). In addition, since the polyimide having a crosslinked structure of the invention of Part I is produced from the above-described polyimide precursor, a polyimide having an appropriate (desirably high) crosslink density can be obtained, the linear expansion coefficient is small, and heating is performed even at a high temperature. It was confirmed that it was excellent in dimensional stability because it was hardly deformed at the time.

  << Example of the invention of Part II >>

  The raw materials used in each of the following examples are as follows.

[Ester derivative of tetracarboxylic acid (A)]
Ester derivative of 3,3 ', 4,4'-biphenyltetracarboxylic acid: s-BPTA / E
Ester derivative of 4,4 '-(hexafluoroisopropylidene) diphthalic acid: 6FDP / E
[Ester derivatives of other tetracarboxylic acids]
Ester derivative of 3,3 ', 4,4'-benzophenonetetracarboxylic acid: BTA / E

[Compound (B) having three or more amino groups]
1,3,5-tris (4-aminophenoxy) benzene: TAPOB

  4,4 ', 4 "-triaminotriphenylamine: TATPA

[Other compounds having three or more amino groups]
2,4,6-triaminopyrimidine: TAP

  1,4,5,8-tetraaminoanthraquinone: TAAQ

[Diamine (C)]
1,3-bis (3-aminophenoxy) benzene: APB
2,2'-bis (trifluoromethyl) benzidine: TFMB
m-phenylenediamine: MPD

[Solvent (D)]
N, N-dimethylacetamide: DMAc
N-methyl-2-pyrrolidone: NMP

[Other]
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride: s-BPDA
4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride: 6FDA
3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride: BTDA
Ethanol: EtOH
1,2-dimethylimidazole: 12DMZ
Glass substrate: 2 mm thick soda glass plate

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

Evaluation of polyimide precursor
[Rotation viscosity], [Logarithmic viscosity], and [Varnish solids] were determined in the same manner as in Part I.

[Molecular weight between crosslinking points]
Table II-1 shows the values obtained from the above equation (6).

Evaluation of film forming properties
[Film-forming property] was evaluated in the same manner as in Part I.

Evaluation of polyimide film
[Thermo-mechanical properties (TMA): glass transition temperature, deformation during heating: 1%, 5%, 10% elongation temperature], [5% thermal weight loss temperature], [bendability], [solvent resistance], [Optical properties: total light transmittance, light transmittance at 420 nm] and [moisture absorption resistance] were evaluated as in Part I.

[Example II-1]
In a glass container, s-BPDA is 1.25 molar equivalent (1.842 g), EtOH is twice as much as tetracarboxylic anhydride (0.577 g), and DMAc is monomer concentration (tetracarboxylic ester derivative). (A), the concentration of the amine compound (B) and the diamine (C) as a solute) was 20 mass% (13.72 g), and 0.02 g of 12DMZ was further added as a catalyst, followed by heating and stirring at 80 ° C. for 3 hours. did. By FT-IR, formation of an ester derivative s-BPTA / E of 3,3 ′, 4,4′-biphenyltetracarboxylic acid was confirmed. To the resulting solution are added 0.5 molar equivalents (1.000 g) of TAPOB as the amine compound (B) and 0.5 molar equivalents (0.732 g) of APB as the diamine (C), and heat-dissolved at 50 ° C. Thus, a polyimide precursor solution (solid content: 20%, viscosity: 62 mPa · s) was obtained.

  The obtained polyimide precursor solution was applied to a glass substrate, dried at 120 ° C. for 5 minutes, and then heated at 150 ° C. and 200 ° C. for 10 minutes each, and then heated at 250 ° C. for 1 hour to thermally imidize. Thus, a polyimide / glass laminate was obtained. Next, the obtained polyimide / glass laminate was immersed in a hot water bath and then peeled off to obtain a polyimide (film) having a film thickness of about 10 μm. Table 1 shows the measurement results of the characteristics of the polyimide.

[Examples II-2 to 5]
Except having changed each component into the description of Table 1, it carried out similarly to Example II-1, and produced the polyimide precursor solution. The obtained polyimide precursor solution was used to obtain a polyimide (film) in the same manner as in Example II-1. Table 1 shows the measurement results of the characteristics of the polyimide.

[Comparative Examples II-1 to 3]
Except having changed each component into the description of Table 1, it carried out similarly to Example II-1, and produced the polyimide precursor solution. The obtained polyimide precursor solution was used to obtain a polyimide (film) in the same manner as in Example II-1. Table 1 shows the measurement results of the characteristics of the polyimide.

[Comparative Example II-5]
In a glass container, 109.53 g (0.340 mol) of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) such that the solid content of the polyimide precursor solution becomes 43% by weight, 45.85 g (1.02 mol) of ethanol and 113.20 g of N-methyl-2-pyrrolidone (NMP) were added, and the mixture was heated to 80 ° C. and stirred for 2 hours to obtain a BTA / E solution. Next, 15.79 g (0.136 mol) of metaphenylenediamine (MPDA) and 18.27 g (0.136 mol) of 2,4,6-triaminopyrimidine (TAP) were added, and the mixture was heated again to 80 ° C. and stirred for 3 hours. Thus, a polyimide precursor solution was obtained. A polyimide (film) was produced from the obtained polyimide precursor solution in the same manner as in Example II-1, but was turned into a powdery form upon heating, and a film was not obtained. Table 1 shows the results of measuring the properties of the polyimide (powder) obtained here.

[Comparative Example II-6]
The input amount of BTDA was changed to 102.70 g (0.319 mol), the input amount of ethanol was changed to 44.05 g (0.956 mol), the input amount of NMP was changed to 115.47 g, and the input amount of MPDA was 20. A polyimide precursor solution was obtained in the same manner as in Comparative Example II-5, except that TAP 18.27 g (0.136 mol) was replaced with TAAQ 17.10 g (0.064 mol) instead of 68 g (0.191 mol). A polyimide (film) was produced from the obtained polyimide precursor solution in the same manner as in Example II-1, but was turned into a powdery form upon heating, and a film was not obtained.

  Table II-1 summarizes the compositions and evaluation results of the examples and comparative examples. FIG. 1 shows the results of thermomechanical analysis (TMA) of the polyimide obtained in Examples II-1 to II-5 and the polyimide obtained in Comparative Example II-1.

  As can be seen from the results shown in Table II-1, the polyimide precursor of the invention of Part II has a higher proportion of the compound (B) having three or more amino groups in the amine compound of the polyimide precursor. Thus, a precursor solution could be produced, and a crosslinked polyimide could be easily obtained by a thermal method (polycondensation and imidization reaction). In addition, since the polyimide having a crosslinked structure of the invention of Part II is manufactured from the above-mentioned polyimide precursor, a polyimide having an appropriate (desirably high) crosslink density can be obtained, the linear expansion coefficient is small, and heating is performed even at a high temperature. It was confirmed that it was excellent in dimensional stability because it was hardly deformed at the time, and that it had flexibility to bend.

  On the other hand, in the case of using a triamine (TAP) other than the amine compound (B) defined in the invention of Part II as in Comparative Examples II-2 to 3, cracks occur in the film at the time of production, and the film is flexible. No film was obtained and the 5% weight loss temperature was low. Further, when a tetracarboxylic acid ester derivative other than the tetracarboxylic acid ester derivative (A) of the invention of Part II is used as in Comparative Examples II-5 to 6, it becomes powder at the time of production and a film is obtained. Could not.

  << Example of the invention of Part III >>

    The raw materials used in each of the following examples are as follows.

[Tetracarboxylic acid (A31)]
3,3 ', 4,4'-biphenyltetracarboxylic acid: s-BPTA
[Tetracarboxylic acid (A32)]
2,3,3 ', 4'-biphenyltetracarboxylic acid: a-BPTA
4,4'-oxydiphthalic acid: ODP
4,4 '-(hexafluoroisopropylidene) diphthalic acid: 6FDP
4,4 '-(4,4'-isopropylidenediphenoxy) bis (phthalic acid): BPABP
3,3 ', 4,4'-benzophenonetetracarboxylic acid: BTTA
[Diamine (B31)]
Paraphenylenediamine: PPD
4,4-diaminodiphenyl ether: 4,4-ODA
2,2-bis [4- (4-aminophenoxy) phenyl] propane: BAPP
[Diamine (B32)]
3,4-diaminodiphenyl ether: 3,4-ODA
[Amine having cyclic structure (H)]
1,2-dimethylimidazole: 12DMZ
1-methylimidazole: 1 Mz
Pyridine: Py
Isoquinoline: IQ
Triethylenediamine: TEDA
Diazabicycloundecene: DBU
[Amine without cyclic structure]
Triethylamine: TEA
Triethanolamine: TEtOHA
[Solvent (D)]
N, N-dimethylacetamide: DMAc
N-methyl-2-pyrrolidone: NMP
[Inorganic particles (E)]
Aerosil 380 (silica particles)
Aerosil R972 (Silica particles with surface treatment)
[Other]
Glass substrate: 2 mm thick soda glass plate

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

[Varnish solids]
1 g of the polyimide precursor solution was weighed and placed in an aluminum Petri dish and heated in a hot air circulating oven at 200 ° C. for 2 hours to remove non-solid content, and the varnish solid content (heating residue mass%) was determined from the remaining mass. Was.

[Solubility]
The solubility of the polyimide precursor solution prepared by the method described in the examples was determined. In the table, 場合 indicates complete dissolution, and X indicates insoluble matter.

[Storage stability]
The storage stability (25 ° C., standing, sealed in a glass container) of the polyimide precursor solution prepared by the method described in the examples was determined. In the table, ◎ indicates that there was no abnormality such as precipitation for one month or more, ○ indicates that there was no abnormality such as precipitation for two weeks or more, and X indicates that abnormality occurred within two weeks.
[Rotating viscosity]
Using Toki Sangyo Co. TV-22 E-type rotational viscometer was determined viscosity of the polyimide precursor solution at a temperature 30 ° C. shear rate 100 sec ^-1 or 10 sec ^-1.

[Film forming property]
The polyimide precursor solution obtained in each example was coated on the washed glass substrate using a bar coater so that the polyimide film had a thickness of 10 μm or 25 μm. After the substrate was dried at 120 ° C. for 5 minutes, it was heated at 150 ° C. and 200 ° C. for 10 minutes and then at 250 ° C. for 1 hour to thermally imidize it. In the table, ◎: no abnormality (a self-supporting film is obtained), ：: noticeable coloring (brown to black) or turbidity of the film (coating can be made), △: whitening and swelling of the film, X: It was described that a film could not be obtained (eg, powdery).

[Bendability]
A polyimide film (thickness 10 μm or 25 μm, width 1 cm, length 5 cm) was sandwiched between slide glasses and bent (split), and a weight of 100 g was placed on the bent portion and allowed to stand for 1 minute. The bent portion was returned, and the case where there was no abnormality was evaluated as ○, the case where whitening occurred at the bent portion as △, and the case where cracks or the like occurred as x.

[Thermo-mechanical properties (TMA): glass transition temperature, linear expansion coefficient]
The polyimide film was cut into a strip having a width of 4 mm to obtain a test piece, and the temperature was raised to 475 ° C. at a chuck length of 15 mm, a load of 2 g, and a heating rate of 20 ° C./min using TMA-50 manufactured by Shimadzu Corporation. The glass transition temperature (° C.) was determined from the inflection point of the obtained TMA curve. The coefficient of linear expansion was an average coefficient of linear expansion at 50 ° C to 200 ° C.

[Tensile properties: elastic modulus, yield point stress, breaking elongation, breaking strength]
The polyimide film was punched out into a dumbbell shape according to IEC450 standard to obtain a test piece, and the measurement was performed using TENSIRON manufactured by ORIENTEC at a distance between chucks of 30 mm and a pulling speed of 2 mm / min. From the obtained SS curve, the elastic modulus, yield point stress, breaking elongation, and breaking strength were determined.

[5% thermal weight loss temperature]
A polyimide film having a film thickness of 10 μm was used as a test piece, and the temperature was increased from 25 ° C. to 600 ° C. at a rate of 10 ° C./min in a nitrogen stream using a differential thermogravimetric simultaneous measurement device (TG / DTA6300) manufactured by SII Nanotechnology. The temperature rose. From the obtained weight curve, a 5% thermal weight loss temperature was determined.

[Example III-1]
0.75 molar equivalent of s-BPTA as tetracarboxylic acid (A31), 0.25 molar equivalent of a-BPTA as tetracarboxylic acid (A32), 1 molar equivalent of 4,4-ODA as diamine (B31), cyclic As a amine having a structure (G), 0.1 mol equivalent of 12DMZ was placed in a mortar, ground sufficiently, and mixed to obtain a polyimide precursor powder. When this powder was checked with a microscope, particles having a particle diameter of 0.5 mm or more were not found. DMAc was added to this powder as a solvent (D) in an amount (9.33 g) to give a monomer concentration of 20% by mass, and heated and dissolved at 50 ° C. to obtain a polyimide precursor solution (solid content: 20%).

    The obtained polyimide precursor solution was applied to a glass substrate, dried at 120 ° C. for 5 minutes, and then heated at 150 ° C. and 200 ° C. for 10 minutes each, and then heated at 250 ° C. for 1 hour to thermally imidize. Thus, a polyimide / glass laminate was obtained. Next, the obtained polyimide / glass laminate was immersed in a hot water bath and then peeled off to obtain a polyimide (film) having a film thickness of about 10 μm and about 25 μm. The results of measuring the properties of this polyimide are shown in Table III-1.

[Examples III-2 to 28]
A polyimide precursor powder and a polyimide precursor solution were prepared in the same manner as in Example III-1, except that the components were changed to those described in Table III-1 (the addition of the solvent was appropriately adjusted). A polyimide (film) was produced in the same manner as in Example III-1. The results are shown in Tables III-1 to III-3.

[Comparative Examples III-1 to III]
A polyimide precursor powder was produced in the same manner as in Example III-1, except that the components were changed to those described in Table III-1, and a solvent was added thereto, followed by heating and stirring, but did not dissolve.

[Comparative Examples III-4 to 8]
A polyimide precursor powder and a polyimide precursor solution were prepared in the same manner as in Example III-1, except that the components were changed to those described in Table III-1 (the addition of the solvent was appropriately adjusted). A polyimide (film) was produced in the same manner as in Example III-1, but it turned into a powdery form and whitened, and a good quality film was not obtained.

[Example III-30]
To the polyimide precursor solution obtained in Example III-25, 20 parts by mass of Aerosil R972 was added to 100 parts by mass of the solid content of the raw material solution, and the mixture was dispersed with a three-roll mill, and the polyimide in which inorganic particles were dispersed was added. A precursor solution (solid content 42%) was obtained. A polyimide (film) was produced in the same manner as in Example III-1. Table III-4 shows the evaluation results of this polyimide.

[Comparative Example III-9]
As a raw material of the polyimide precursor solution, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride 0.8 molar equivalent, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride 0. 2 molar equivalents and 1 molar equivalent of 4,4-diaminodiphenyl ether were added, and a polyamic acid solution (polyimide precursor solution) was obtained by a known production method. The solid concentration of this solution was 20%.

    A polyimide (film) was produced in the same manner as in Example III-1. Table III-4 shows the evaluation results of this polyimide.

  As can be seen from the results shown in Tables III-1 to III-4, the polyimide precursor solution of the invention of Part III has excellent solubility, enables high solid differentiation, and has excellent storage stability. Furthermore, the polyimide obtained from the polyimide precursor of the invention of Part III has excellent film-forming properties and can form a high-quality film having bendability. Furthermore, it is excellent in characteristics such as high mechanical strength (elastic modulus, stress at yield, stress at break) and low coefficient of linear expansion as compared with polyimide obtained from conventional polyamic acid.

Claims (36)

A polyimide precursor for producing a polyimide having a crosslinked structure,
At least a tetracarboxylic acid (a) and an amine compound (b) having three or more amino groups are included, and when a polyimide is formed, a crosslinked structure is formed by the amine compound (b),
The amine compound (b) is contained in an amount of 1 mol% or more based on the total molar amount of all amine components composed of the amine compound (b) and, if present, the diamine (C);
A polyimide precursor, wherein the amine compound (b) includes at least one selected from amine compounds represented by the general formula (3).

[In the formula, Z ₁ is a trivalent or more valent group, Z ₂ and Z ₃ are a direct bond or a divalent group, R _{31 to} R ₃₆ each independently represent a monovalent group, and n ₁ is 3 or more. , M ₁ and m ₃ represent an integer of 0 to 4, and m ₂ and m _{4 to} m ₆ represent an integer of 0 to 3. ] The polyimide precursor according to claim 1, wherein the polyimide precursor (a) contains at least one kind of tetracarboxylic acid selected from the compounds represented by the general formula (1).

[X1 in the formula is a direct bond or a divalent group. ] As the tetracarboxylic acid (a), pyromellitic acid and the general formula:

And wherein X ₁ contains at least one selected from the group consisting of a direct bond or a tetracarboxylic acid which is any divalent group represented by the following general formula (2). Or the polyimide precursor according to 2.

[X ₂ in the formula is a divalent organic group. ]   The polyimide precursor according to any one of claims 1 to 3, further comprising a diamine (C). The polyimide precursor according to any one of claims 1 to 4, comprising a solvent (D) and not containing both a dehydrating agent and a catalyst for a polycondensation reaction and a ring closing reaction. The polyimide precursor according to claim 4 , wherein the diamine (C) includes at least one selected from compounds represented by the general formula (4).

[In the formula, Y ₁ represents a direct bond or a divalent group, R _{5 to} R ₇ each independently represent a monovalent group, and m _{5 to} m ₇ represent an integer of 0 to 4. ] The polyimide precursor according to any one of claims 1 to 4, which is a powder having a particle diameter of 5 mm or less. A polyimide precursor solution comprising the polyimide precursor according to any one of claims 1 to 6 and a solvent (D). A method for producing a polyimide having a crosslinked structure, comprising a step of imidizing the polyimide precursor according to any one of claims 1 to 7 or the polyimide precursor in a solution according to claim 8 . A polyimide having a structural unit derived from a tetracarboxylic acid component and a structural unit derived from an amine component,
The structural unit derived from the amine component may be a structural unit derived from an amine compound (bi) having three or more amino groups and a diamine (Ci), respectively, in a range where the value of the following formula is 0.01 to 1. Included in
[Total moles of amine compound (bi)] / ([Total moles of amine compound (bi)] + [Total moles of diamine (Ci)])
The tetracarboxylic acid component is a tetracarboxylic acid selected from compounds represented by the following general formula (1),
A polyimide having a crosslinked structure having a glass transition temperature Tg of 296 ° C. or lower (except for a polyimide obtained by curing the following curable polyimide resin composition (A)) .

[X ₁ in the formula is a direct bond or the following general formula (2):

Represents a divalent group selected from the groups represented by the following formula, wherein X ₂ represents a general formula:

(Wherein R _{111 to} R ₁₂₄ are a direct bond, and

A group selected from the group consisting of )
And a divalent organic group selected from the group consisting of ]
(A) Curable polyimide resin composition:
(A) The following general formula (1):

(Wherein, R ¹ is independently a divalent organic group having 1 to 10 carbon atoms, R ² is independently a monovalent organic group having 1 to 8 carbon atoms, and X is an aromatic ring or Tetravalent organics containing aliphatic rings
M is an integer of 1 to 200, and n is an integer of 2 or more), (B) a polyamic acid represented by the following general formula (2):

(Wherein, R ³ is independently an alkyl group, and X is as described above), (C) an aromatic diamine, and (D) an aromatic polyamine having three or more functional groups. And (E) a curable polyimide resin composition comprising an organic solvent. A polyimide film comprising the polyimide having a crosslinked structure according to claim 10 . A polyimide precursor for producing a polyimide having a crosslinked structure, at least,
A tetracarboxylic ester derivative (A) selected from the compounds represented by the general formula (II-1),
Amine compound (B) having three or more amino groups selected from compounds represented by general formula (II-3)
When a polyimide is formed, a crosslinked structure is formed by the amine compound (B) having three or more amino groups, and the molecular weight α between crosslinked points is in the range of 1300 to 10,000 g / mol. A polyimide precursor, characterized in that:

[In the formula, X ₁ represents a direct bond or a divalent group selected from groups represented by the following formula (II-2), and R _{11 to} R ₃₀ each independently represent hydrogen or C 1-8. It represents a monovalent aliphatic group (except when it becomes tetracarboxylic acid). ]

[X ₂ in the formula is a general formula:

(Wherein R _{111 to} R ₁₂₄ are a direct bond, and

A group selected from the group consisting of )
And a divalent organic group selected from the group consisting of ]

[Z ₁ is a trivalent nitrogen atom, a trivalent or higher aromatic group, a trivalent or higher aliphatic group, Z ₂ and Z ₃ are a direct bond or a divalent group, and R _{31 to} R ₃₆ are monovalent. aromatic group, an aliphatic group, a halogen, _{n 1} is 3 or more, _{m 1} and _{m 3} is 0 to 4, _{m 2} and _m 4 ~m ₆ represents an integer of 0 to 3. ] The polyimide precursor according to claim 12 , further comprising a diamine (C). The polyimide precursor according to claim 13 , wherein the proportion of the amine compound (B) represented by the following formula is in the range of 0.01 to 1.
[Total mole number of the amine compound (B)] / ([Total mole number of the amine compound (B)] + [Total mole number of the diamine (C)]) 15. The polyimide precursor according to claim 13 , wherein the diamine (C) contains at least one or more compounds selected from the compounds represented by the general formula (II-4). 16 .

[Wherein Y ₁ represents a direct bond or a divalent group, R _{41 to} R ₄₃ each independently represent a monovalent aromatic group, an aliphatic group, or a halogen, and m _{5 to} m ₇ represent 0 to 4 Represents an integer. ] A polyimide precursor solution, comprising: the polyimide precursor according to any one of claims 12 to 15 ; and a solvent (D). A method for producing a polyimide, comprising: imidizing the polyimide precursor according to any one of claims 12 to 15 to produce a polyimide having a crosslinked structure. A polyimide having a structural unit derived from a tetracarboxylic acid component and a structural unit derived from an amine component,
Structural units derived from the amine component are structural units derived from an amine compound (Bi) having three or more amino groups and a diamine (Ci), respectively, in a range where the value of the following formula is 0.01 to 1. Included in
[Total moles of amine compound (Bi)] / ([Total moles of amine compound (Bi)] + [Total moles of diamine (Ci)])
The tetracarboxylic acid component is a tetracarboxylic ester derivative (A) selected from compounds represented by the following general formula (II-1),
The amine compound (Bi) having three or more amino groups is selected from the compounds represented by the general formula (II-3) ,
A polyimide having a crosslinked structure , wherein the molecular weight α between crosslink points is in the range of 1300 to 10,000 g / mol .

[In the formula, X ₁ represents a direct bond or a divalent group selected from groups represented by the following formula (II-2), and R _{11 to} R ₃₀ each independently represent hydrogen or C 1-8. It represents a monovalent aliphatic group (except when it becomes tetracarboxylic acid). ]

[X ₂ in the formula is a general formula:

(Wherein, R _{111 to} R ₁₂₄ are a direct bond, and

A group selected from the group consisting of )
And a divalent organic group selected from the group consisting of ]

[Z ₁ is a trivalent nitrogen atom, a trivalent or higher aromatic group, a trivalent or higher aliphatic group, Z ₂ and Z ₃ are a direct bond or a divalent group, and R _{31 to} R ₃₆ are monovalent. aromatic group, an aliphatic group, a halogen, _{n 1} is 3 or more, _{m 1} and _{m 3} is 0 to 4, _{m 2} and _m 4 ~m ₆ represents an integer of 0 to 3. ] A film comprising the polyimide having a crosslinked structure according to claim 18 . Tetracarboxylic acid (A31) which is 3,3 ′, 4,4′-biphenyltetracarboxylic acid;
A tetracarboxylic acid component comprising the tetracarboxylic acid (A31) and a tetracarboxylic acid (A32) that is a different tetracarboxylic acid;
A diamine component containing an aromatic diamine (B31) represented by the following general formula (III-1); and an amine compound (G) having a cyclic structure in the molecule (wherein the amine compound (G) is a diamine compound and a Is not a compound having three or more amino groups at the same time)
A polyimide precursor comprising:

[Y ₁ in the formula is a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene or an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, or Represents any molecular structure represented by the general formula (III-2), and R _{1 to} R ₃ each independently represent an aromatic group having 12 or less carbon atoms, an alkyl group having 1 to 6 carbon atoms, a halogen group, It is a hydroxyl group or a carboxylic acid group, and n _{1 to} n ₃ represent an integer of 0 to 4. ]

[Y ₂ in the formula represents a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, dimethylsilylene, or an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, R ₄ and R ₅ each independently represent an alkylene having 1 to 6 carbon atoms or an aromatic group having 12 or less carbon atoms. ] The polyimide precursor according to claim 20 , wherein the tetracarboxylic acid (A32) contains one or more kinds of tetracarboxylic acids represented by the general formula (III-3).

[X ₁ in the formula is a direct bond or a divalent group. However, when X ₁ is a direct bond, 3,3 ′, 4,4′-biphenyltetracarboxylic acid is excluded. ] The tetracarboxylic acid (A32) is pyromellitic acid, and X1 in the general formula (III-3) is a direct bond, an ether bond, an ester bond, an amide bond, a ketone bond, methylene, isopropylidene, hexafluoroisopropylidene. It contains at least one selected from lidene, dimethylsilylene, an alkylene having 1 to 6 carbon atoms, an aromatic group having 12 or less carbon atoms, and a tetracarboxylic acid represented by formula (III-4). 22. The polyimide precursor according to claim 20, wherein:

[X ₂ in the formula is a divalent organic group. ] The polyimide according to any one of claims 20 to 22 , wherein the tetracarboxylic acid component contains 50 mol% or more of a tetracarboxylic acid (A31) based on a total molar amount of all tetracarboxylic acid components. precursor. The diamine component, a said diamine (B31) and different diamine, claim general formula comprises a (III-5) 1 or more diamines selected from the compounds represented by (B32), wherein 20 24. The polyimide precursor according to any one of items 23 to 23 .

[Wherein Y ₃ represents a direct bond or a divalent group, and R _{6 to} R ₈ each independently represent an aromatic group having 12 or less carbon atoms, an alkyl group having 1 to 6 carbon atoms, a halogen group, a hydroxyl group, It is a carboxylic acid group, and n _{4 to} n ₆ represent an integer of 0 to 4. However, the diamine represented by the general formula (III-1) is excluded. ] The polyimide precursor according to any one of claims 20 to 24 , wherein the diamine component contains the diamine (B31) in an amount of 50 mol% or more based on the total molar amount of all diamine components. The polyimide precursor according to any one of claims 20 to 25 , wherein the amine compound (G) is selected from the group consisting of an aliphatic amine having a cyclic structure, an aromatic amine, and a heterocyclic amine. body. The polyimide precursor according to any one of claims 20 to 26 , wherein the amine compound (G) contains nitrogen as a ring member atom. The amine compound (G) is, pyridine, pyrazine, pyrimidine, pyridazine, triazine, pyrrole, imidazole, pyrazole, oxazole or according to any one of claims 20-27 characterized by having a isoxazole skeleton, Polyimide precursor. The polyimide precursor according to any one of claims 20 to 28 , wherein the amine compound (G) is contained in an amount of 10 mol% or more based on the total molar amount of all tetracarboxylic acid components. A polyimide precursor solution, comprising: the polyimide precursor according to any one of claims 20 to 29 ; and a solvent (D). The polyimide precursor solution according to claim 30 , further comprising inorganic particles (E). The polyimide precursor according to any one of claims 1 to 7 , 12 to 15 , and 20 to 29 , or the polyimide precursor solution according to any one of claims 8 , 16 , 30, and 31. Producing a polyimide laminate in which a polyimide layer and a layer or a substrate of at least one material selected from glass, metal, resin and ceramic are laminated. The polyimide precursor according to any one of claims 1 to 7 , 12 to 15 , and 20 to 29 , or the polyimide precursor solution according to any one of claims 8 , 16 , 30, and 31. A polyimide laminate in which the obtained polyimide layer and at least one layer or substrate selected from glass, metal, resin and ceramic are laminated. The polyimide precursor according to any one of claims 1 to 7 , 12 to 15 , and 20 to 29 , or the polyimide precursor solution according to any one of claims 8 , 16 , 30, and 31. And manufacturing a substrate selected from a heat-resistant electric wire insulating layer, a sliding component, a flexible circuit board, or a display substrate, a touch panel substrate, a solar cell substrate, and a thin film semiconductor substrate. A solution for producing a film or forming a polyimide coating film, comprising the polyimide precursor according to any one of claims 1 to 7 , 12 to 15 , and 20 to 29 . The polyimide precursor according to any one of claims 1 to 4 , 6 to 7, 12 to 15 , and 20 to 29 , which is a powder having a particle diameter of 5 mm or less.

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