CN113166413B

CN113166413B - Polyimide resin composition and polyimide film

Info

Publication number: CN113166413B
Application number: CN201980080632.4A
Authority: CN
Inventors: 安孙子洋平; 关口慎司; 高田贵文
Original assignee: Mitsubishi Gas Chemical Co Inc
Current assignee: Mitsubishi Gas Chemical Co Inc
Priority date: 2018-12-13
Filing date: 2019-12-06
Publication date: 2024-02-09
Anticipated expiration: 2039-12-06
Also published as: CN113166413A; WO2020121949A1; KR20210102216A; TW202031728A; JPWO2020121949A1; TWI844593B; JP7392657B2

Abstract

The present invention provides a polyimide resin composition, and a polyimide film, wherein the polyimide resin composition comprises a polyimide resin and a cross-linking agent with at least 2 oxazolyl groups, and the polyimide resin comprises: structural units a derived from tetracarboxylic dianhydride and structural units B derived from diamine, the structural units a comprising: a structural unit (A-1) derived from a compound represented by the following formula (a-1), the structural unit B comprising: the polyimide film is formed by crosslinking the polyimide resin in the polyimide resin composition with the crosslinking agent, and the structural unit (B-1) is derived from the compound represented by the following formula (B-1), the structural unit (B-2) is derived from the compound represented by the following formula (B-2), and the structural unit (B-3) is derived from the compound represented by the following formula (B-3). (in the formula (b-1), X is a single bond or a specific group, p is an integer of 0 to 2, m1 is an integer of 0 to 4, m2 is an integer of 0 to 4; in the formula (b-2), R ¹ ～R ⁴ Each independently is a monovalent aliphatic group or a monovalent aromatic group, Z ¹ And Z ² Each independently is a divalent aliphatic group or a divalent aromatic group, and r is a positive integer. )

Description

Polyimide resin composition and polyimide film

Technical Field

The present invention relates to a polyimide resin composition and a polyimide film.

Background

Polyimide resins have excellent mechanical properties and heat resistance, and therefore various uses have been studied in the fields of electric/electronic parts and the like. For example, for the purpose of weight reduction and flexibility of devices, it is desired to replace a glass substrate used in an image display device such as a liquid crystal display or an OLED display with a plastic substrate, and research on polyimide films suitable for the plastic substrate has been advanced. Colorless transparency is required for polyimide films for such applications.

As a polyimide film suitable for the above-mentioned applications, a polyimide film produced by adding a crosslinking agent to a polyimide resin has been proposed. Patent document 1 discloses a polyimide resin composition containing a polyimide resin having a carboxyl group and a crosslinking agent having at least 2 oxazolyl groups, and describes that a film having good transparency and high hardness can be formed by the polyimide resin composition.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication 2016-222797

Disclosure of Invention

Problems to be solved by the invention

In an image display device, when light emitted from a display element is emitted through a plastic substrate, colorless transparency is required for the plastic substrate, and when light passes through a retardation film or a polarizing plate (for example, a liquid crystal display, a touch panel, or the like), not only colorless transparency but also high optical isotropy is required. However, patent document 1 does not describe any optical isotropy.

Furthermore, chemical resistance (solvent resistance, acid resistance) is also required for polyimide films to be suitable as substrates. For example, when a varnish for forming a resin layer (e.g., a color filter or a resist) is applied to a polyimide film to form another resin layer on the polyimide film, the polyimide film is required to have resistance to a solvent contained in the varnish. If the solvent resistance of the polyimide film is insufficient, the film may be dissolved or swelled, and the meaning of the polyimide film as a substrate may be lost.

In addition, when a polyimide film is used as a substrate for forming an ITO (Indium Tin Oxide) film, the polyimide film requires resistance to an acid used for etching the ITO film. If the acid resistance of the polyimide film is insufficient, the film may be yellowing and the colorless transparency may be impaired.

In patent document 1, the resistance to the solvent (N, N-dimethylacetamide) is evaluated, but the acid resistance is not evaluated.

In addition, a polyimide resin composition containing a polyimide resin and a crosslinking agent may undergo gelation due to crosslinking even when stored at normal temperature by a combination of the polyimide resin and the crosslinking agent, and in this case, the polyimide resin composition is not suitable for long-term storage.

Further, there is a demand for solubility of a polyimide resin composition in a cleaning liquid (for example, "OK73 thin" manufactured by tokyo applied chemical company, ltd.) used in piping and equipment used for coating the polyimide resin composition and the like. If the solubility of the cleaning liquid is low, there is a concern that the cleaning of the piping and the apparatus using the cleaning liquid becomes insufficient.

Patent document 1 does not describe any storage stability or cleaning property of the polyimide resin composition.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide: a polyimide resin composition which can form a film excellent in colorless transparency, optical isotropy, and chemical resistance (solvent resistance and acid resistance), and is excellent in storage stability and cleaning property; providing: the polyimide resin in the polyimide resin composition is a polyimide film obtained by crosslinking a polyimide resin with a crosslinking agent.

Solution for solving the problem

The inventors found that: the polyimide resin composition containing a polyimide resin containing a combination of specific structural units and a specific crosslinking agent can solve the above-mentioned problems, and thus has completed the present invention.

That is, the present invention relates to [1] to [11] described below.

[1]

A polyimide resin composition comprising a polyimide resin and a crosslinking agent having at least 2 oxazolyl groups,

the polyimide resin has: structural units A derived from tetracarboxylic dianhydrides and structural units B derived from diamines,

the structural unit A comprises: a structural unit (A-1) derived from a compound represented by the following formula (a-1),

the structural unit B comprises: a structural unit (B-1) derived from a compound represented by the following formula (B-1), a structural unit (B-2) derived from a compound represented by the following formula (B-2), and a structural unit (B-3) derived from a compound represented by the following formula (B-3).

(in the formula (b-1),

x is a single bond, a substituted or unsubstituted alkylene group, a carbonyl group, an ether group, a group represented by the following formula (b-1-i), or a group represented by the following formula (b-1-ii),

p is an integer of 0 to 2,

m1 is an integer of 0 to 4,

m2 is an integer of 0 to 4,

[ formula (b-1-i) wherein m3 is an integer of 0 to 5, and formula (b-1-ii) wherein m4 is an integer of 0 to 5. ]

Wherein,

m1+m2+m3+m4 is 1 or more,

when p is 0, m1 is an integer of 1 to 4,

when p is 2, 2X and 2 m2 to m4 are independently selected;

in the formula (b-2), the amino acid sequence,

R ¹ ～R ⁴ each independently of the otherIs a monovalent aliphatic group or a monovalent aromatic group,

Z ¹ And Z ² Each independently is a divalent aliphatic group or a divalent aromatic group,

r is a positive integer. )

[2]

The polyimide resin composition according to the above [1], wherein the structural unit (B-1) is a structural unit (B-11) derived from a compound represented by the following formula (B-11).

[3]

The polyimide resin composition according to the above [1] or [2], wherein the crosslinking agent is: a compound comprising an aromatic ring or an aromatic heterocyclic ring to which at least 2 oxazolyl groups are bonded.

[4]

The polyimide resin composition according to the above [3], wherein the crosslinking agent is: a compound comprising a benzene ring bonded with at least 2 oxazolyl groups.

[5]

The polyimide resin composition according to the above [4], wherein the crosslinking agent is 1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene.

[6]

The polyimide resin composition according to any one of the above [1] to [5], wherein the ratio of the structural unit (A-1) in the structural unit A is 50 mol% or more.

[7]

The polyimide resin composition according to any one of the above [1] to [6], wherein,

the ratio of the structural unit (B-1) in the structural unit B is 20 to 75 mol%,

the ratio of the structural unit (B-2) in the structural unit B is 1 to 25 mol%,

The ratio of the structural unit (B-3) in the structural unit B is 20 to 75 mol%.

[8]

The polyimide resin composition according to any one of the above [1] to [7], wherein the structural unit A further comprises: structural unit (A-2) derived from a compound represented by the following formula (a-2).

[9]

The polyimide resin composition according to the above [8], wherein,

the ratio of the structural unit (A-1) in the structural unit A is 50 to 99 mol%,

the ratio of the structural unit (A-2) in the structural unit A is 1 to 50 mol%.

[10]

A polyamide varnish, comprising: the polyimide resin composition according to any one of the above [1] to [9], and an organic solvent.

[11]

A polyimide film obtained by crosslinking the polyimide resin in the polyimide resin composition according to any one of the above [1] to [9] with the crosslinking agent.

ADVANTAGEOUS EFFECTS OF INVENTION

The polyimide resin composition of the present invention is excellent in storage stability and cleaning properties, and can be formed into a film excellent in colorless transparency, optical isotropy, and chemical resistance (solvent resistance and acid resistance).

Detailed Description

[ polyimide resin composition ]

The polyimide resin composition of the present invention comprises a polyimide resin and a crosslinking agent. Hereinafter, the polyimide resin and the crosslinking agent in the present invention will be described.

< polyimide resin >)

In the present invention, a polyimide resin comprises: structural units a derived from tetracarboxylic dianhydride and structural units B derived from diamine, the structural units a comprising: a structural unit (A-1) derived from a compound represented by the following formula (a-1), the structural unit B comprising: a structural unit (B-1) derived from a compound represented by the following formula (B-1), a structural unit (B-2) derived from a compound represented by the following formula (B-2), and a structural unit (B-3) derived from a compound represented by the following formula (B-3).

In the formula (b-1), the amino acid sequence,

p is an integer of 0 to 2,

m1 is an integer of 0 to 4,

m2 is an integer of 0 to 4.

(in the formula (b-1-i), m3 is an integer of 0 to 5, and in the formula (b-1-ii), m4 is an integer of 0 to 5.)

Wherein,

m1+m2+m3+m4 is 1 or more,

when p is 0, m1 is an integer of 1 to 4,

when p is 2, 2X and 2 m2 to m4 are independently selected.

In the formula (b-2), the amino acid sequence,

R ¹ ～R ⁴ each independently is a monovalent aliphatic group or a monovalent aromatic group,

r is a positive integer.

(structural unit A)

The structural unit A is a structural unit derived from tetracarboxylic dianhydride in a polyimide resin, and comprises a structural unit (A-1) derived from a compound represented by the following formula (a-1).

The compound represented by the formula (a-1) is 1,2,4, 5-cyclohexane tetracarboxylic dianhydride.

The structural unit A can improve the colorless transparency and optical isotropy of the film by containing the structural unit (A-1).

The ratio of the structural unit (A-1) in the structural unit A is preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably 85 mol% or more. The upper limit of the ratio of the structural unit (A-1) is not particularly limited, that is, 100 mol%. The structural unit A may be constituted only by the structural unit (A-1).

The structural unit A may contain structural units other than the structural unit (A-1). The tetracarboxylic dianhydride providing such a structural unit is not particularly limited, and examples thereof include aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride, 3', 4' -biphenyl tetracarboxylic dianhydride, 9 '-bis (3, 4-dicarboxyphenyl) fluorene dianhydride, and 4,4' - (hexafluoroisopropylidene) diphthalic anhydride; alicyclic tetracarboxylic dianhydrides such as 1,2,3, 4-cyclobutane tetracarboxylic dianhydride and norbornane-2-spiro- α -cyclopentanone- α' -spiro-2 "-norbornane-5, 5",6 "-tetracarboxylic dianhydride (excluding compounds represented by formula (a-1)); aliphatic tetracarboxylic dianhydrides such as 1,2,3, 4-butanetetracarboxylic dianhydride.

In the present specification, the aromatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing 1 or more aromatic rings, the alicyclic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing 1 or more alicyclic rings and not containing an aromatic ring, and the aliphatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride not containing an aromatic ring and an alicyclic ring.

The number of structural units (i.e., structural units other than the structural unit (A-1)) arbitrarily contained in the structural unit A may be 1 or 2 or more.

Among the above-mentioned exemplary compounds, 4' - (hexafluoroisopropylidene) diphthalic anhydride is preferred as the tetracarboxylic dianhydride providing the structural unit arbitrarily contained in the structural unit a. That is, in the polyimide resin composition according to one embodiment of the present invention, the structural unit a of the polyimide resin further includes a structural unit (a-2) derived from a compound represented by the following formula (a-2).

The structural unit A can further improve the optical isotropy of the film by containing the structural unit (A-2).

When the structural unit A includes the structural unit (A-1) and the structural unit (A-2), the ratio of the structural unit (A-1) in the structural unit A is preferably 50 to 99 mol%, more preferably 50 to 95 mol%, still more preferably 70 to 95 mol%, particularly preferably 85 to 95 mol%, and the ratio of the structural unit (A-2) in the structural unit A is preferably 1 to 50 mol%, more preferably 5 to 50 mol%, still more preferably 5 to 30 mol%, particularly preferably 5 to 15 mol%.

The ratio of the total of the structural units (A-1) and the structural units (A-2) in the structural unit A is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, particularly preferably 99 mol% or more. The upper limit of the ratio of the total of the structural units (A-1) and (A-2) is not particularly limited, that is, 100 mol%. The structural unit A may be composed of only the structural unit (A-1) and the structural unit (A-2).

(structural unit B)

The structural unit B is a structural unit derived from diamine in a polyimide resin, and includes: a structural unit (B-1) derived from a compound represented by the following formula (B-1), a structural unit (B-2) derived from a compound represented by the following formula (B-2), and a structural unit (B-3) derived from a compound represented by the following formula (B-3).

In the formula (b-1), the amino acid sequence,

p is an integer of 0 to 2,

m1 is an integer of 0 to 4,

m2 is an integer of 0 to 4.

Wherein,

m1+m2+m3+m4 is 1 or more,

when p is 0, m1 is an integer of 1 to 4,

When p is 2, 2X and 2 m2 to m4 are independently selected.

In the formula (b-2), the amino acid sequence,

r is a positive integer.

Specific examples of the compound represented by the formula (b-1) include compounds represented by the following formulas (b-11) to (b-17).

Among the above-mentioned compounds, the compound represented by the formula (b-11) is preferable, and the compound represented by the following formula (b-111), namely, 3, 5-diaminobenzoic acid, is more preferable.

The structural unit (B-1) is a structural unit which provides a carboxyl group to the polyimide resin. The polyimide resins have carboxyl groups, and thus crosslinking of the polyimide resins with each other by a crosslinking agent described later is possible. The structural unit B contains the structural unit (B-1), whereby the chemical resistance of the film can be improved.

R in formula (b-2) ¹ 、R ² 、R ³ And R is ⁴ Each independently represents a monovalent aliphatic group or a monovalent aromatic group, optionally substituted with a fluorine atom. Examples of the monovalent aliphatic group include monovalent saturated hydrocarbon groups and monovalent unsaturated hydrocarbon groups. Examples of the monovalent saturated hydrocarbon group include an alkyl group having 1 to 22 carbon atoms, such as methyl, ethyl, and propyl. Examples of the monovalent unsaturated hydrocarbon group include alkenyl groups having 2 to 22 carbon atoms, for example, vinyl groups and propenyl groups. Examples of monovalent aromatic groups include aryl groups having 6 to 24 carbon atoms, aralkyl groups, and the like. As R ¹ 、R ² 、R ³ And R is ⁴ Methyl or phenyl is particularly preferred.

In addition, Z ¹ And Z ² Each independently represents a divalent aliphatic group or a divalent aromatic group, which groups are optionally substituted with fluorine atoms, optionally containing oxygen atoms. When an oxygen atom is contained as an ether bond, the carbon number indicated below refers to the total carbon number contained in an aliphatic group or an aromatic group. Examples of the divalent aliphatic group include a divalent saturated hydrocarbon group and a divalent unsaturated hydrocarbon group. Examples of the divalent saturated hydrocarbon group include an alkylene group having 1 to 22 carbon atoms, an alkyleneoxy group, and a saturated hydrocarbon group having an ether bond, examples of the alkylene group include a methylene group, an ethylene group, and a propylene group, and examples of the alkyleneoxy group include a propyleneoxy group and a trimethyleneoxy group. Examples of the divalent unsaturated hydrocarbon group include an unsaturated hydrocarbon group having 2 to 22 carbon atoms, such as an ethenylene group, an propenylene group, and an alkylene group having an unsaturated double bond at the terminal. Examples of the divalent aromatic group include a phenylene group having 6 to 24 carbon atoms, a phenylene group substituted with an alkyl group, and an aralkylene group. As Z ¹ And Z ² Propylene, phenylene, aralkylene are particularly preferred.

R is a positive integer, preferably an integer of 10 to 10000.

As described above, among the compounds represented by the formula (b-2), the compounds represented by the following formula (b-21) are preferable.

(in the formula (b-21), m and n each independently represent an integer of 1 or more, and the sum of m and n is an integer of 10 to 10000.)

The sum of m and n (m+n) is preferably 10 to 1000, more preferably 10 to 500, still more preferably 10 to 100, still more preferably 10 to 50.

The ratio of m/n is preferably 5/95 to 50/50, more preferably 10/90 to 40/60, still more preferably 20/80 to 30/70.

Examples of the compound represented by the formula (b-2) include: 1, 3-bis (3-aminopropyl) -1, 2-tetramethyldisiloxane, 1, 3-bis (3-aminobutyl) -1, 2-tetramethyldisiloxane, bis (4-aminophenoxy) dimethylsilane, 1, 3-bis (4-aminophenoxy) tetramethyldisiloxane, 1, 3-tetramethyl-1, 3-bis (4-aminophenyl) disiloxane, 1, 3-tetraphenoxy-1, 3-bis (2-aminoethyl) disiloxane 1, 3-tetraphenyl-1, 3-bis (2-aminoethyl) disiloxane, 1, 3-tetraphenyl-1, 3-bis (3-aminopropyl) disiloxane 1, 3-tetramethyl-1, 3-bis (2-aminoethyl) disiloxane, 1, 3-tetramethyl-1, 3-bis (3-aminopropyl) disiloxane 1, 3-tetramethyl-1, 3-bis (4-aminobutyl) disiloxane, 1, 3-dimethyl-1, 3-dimethoxy-1, 3-bis (4-aminobutyl) disiloxane 1, 3-tetramethyl-1, 3-bis (4-aminobutyl) disiloxane 1, 3-dimethyl-1, 3-dimethoxy-1, 3-bis (4-aminobutyl) disiloxane, 1, 5-tetraphenyl-3, 3-dimethoxy-1, 5-bis (5-aminopentyl) trisiloxane, 1, 5-tetramethyl-3, 3-dimethoxy-1, 5-bis (2-aminoethyl) trisiloxane, 1, 5-tetramethyl-3, 3-dimethoxy-1, 5-bis (4-aminobutyl) trisiloxane 1, 5-tetramethyl-3, 3-dimethoxy-1, 5-bis (5-aminopentyl) trisiloxane, 1,3, 5-hexamethyl-1, 5-bis (3-aminopropyl) trisiloxane, 1,3, 5-hexaethyl-1, 5-bis (3-aminopropyl) trisiloxane 1,3, 5-hexapropyl-1, 5-bis (3-aminopropyl) trisiloxane, and the like. The above compounds may be used alone or in combination of 2 or more.

As commercially available products of the compound represented by the formula (B-2), there may be mentioned "X-22-9409", "X-22-1660B", "X-22-161A", "X-22-161B" manufactured by Kagaku Kogyo Co., ltd.

The structural unit B can improve the colorless transparency and optical isotropy of the film and the cleanability of the polyimide resin composition by containing the structural unit (B-2).

The compound represented by the formula (b-3) is 4,4 '-diamino-2, 2' -bistrifluoromethyl diphenyl ether.

The structural unit B can improve the optical isotropy of the film, and the storage stability and cleaning property of the polyimide resin composition by containing the structural unit (B-3).

The ratio of the structural unit (B-1) in the structural unit B is preferably 20 to 75 mol%, more preferably 25 to 70 mol%, still more preferably 30 to 60 mol%.

The ratio of the structural unit (B-2) in the structural unit B is preferably 1 to 25 mol%, more preferably 2 to 20 mol%, still more preferably 3 to 15 mol%.

The ratio of the structural unit (B-3) in the structural unit B is preferably 20 to 75 mol%, more preferably 25 to 70 mol%, still more preferably 30 to 60 mol%.

The total ratio of the structural units (B-1) to (B-3) in the structural unit B is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, particularly preferably 99 mol% or more. The upper limit of the total ratio of the structural units (B-1) to (B-3) is not particularly limited, and is 100 mol%. The structural unit B may be composed of only the structural unit (B-1), the structural unit (B-2) and the structural unit (B-3).

The structural unit B may contain structural units other than the structural units (B-1) to (B-3). The diamine providing such a structural unit is not particularly limited, and examples thereof include: aromatic diamines of formula (b) wherein the aromatic diamines (b) are excluded are represented by the formula (1), and the aromatic diamines (b) are represented by the formula (1), wherein the aromatic diamines are represented by the formula (b); alicyclic diamines such as 1, 3-bis (aminomethyl) cyclohexane and 1, 4-bis (aminomethyl) cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine (among them, the compounds represented by the formula (b-2) are excluded).

In the present specification, an aromatic diamine means a diamine containing 1 or more aromatic rings, an alicyclic diamine means a diamine containing 1 or more alicyclic rings and containing no aromatic rings, and an aliphatic diamine means a diamine containing neither aromatic rings nor alicyclic rings.

The number of structural units (i.e., structural units other than the structural units (B-1) to (B-3)) included in the structural unit B may be 1 or 2 or more.

In the present invention, the number average molecular weight of the polyimide resin is preferably 5000 to 100000 from the viewpoint of the mechanical strength of the obtained polyimide film. The number average molecular weight of the polyimide resin can be determined, for example, from a standard polymethyl methacrylate (PMMA) conversion measured by gel filtration chromatography.

Method for producing polyimide resin

In the present invention, the polyimide resin can be produced by reacting a tetracarboxylic acid component comprising a compound providing the above-mentioned structural unit (A-1), a diamine component comprising a compound providing the above-mentioned structural unit (B-1), a compound providing the above-mentioned structural unit (B-2), and a compound providing the above-mentioned structural unit (B-3).

The compound providing the structural unit (A-1) may be a compound represented by the formula (a-1), but is not limited thereto, and may be a derivative thereof within a range in which the same structural unit is provided. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-1) (i.e., 1,2,4, 5-cyclohexane tetracarboxylic acid), and an alkyl ester of the tetracarboxylic acid. As the compound providing the structural unit (A-1), a compound represented by the formula (a-1) (i.e., dianhydride) is preferable.

The tetracarboxylic acid component preferably contains 50 mol% or more of the compound providing the structural unit (a-1), more preferably 70 mol% or more, and still more preferably 85 mol% or more. The upper limit of the content ratio of the compound providing the structural unit (A-1) is not particularly limited, that is, 100 mol%. The tetracarboxylic acid component may be constituted only by the compound providing the structural unit (A-1).

The tetracarboxylic acid component may contain compounds other than the compound providing the structural unit (a-1), and examples of the compound include the aromatic tetracarboxylic dianhydride, the alicyclic tetracarboxylic dianhydride, the aliphatic tetracarboxylic dianhydride, and derivatives thereof (tetracarboxylic acid, alkyl esters of tetracarboxylic acid, and the like).

The number of compounds (i.e., compounds other than the compound providing the structural unit (A-1)) contained in any of the tetracarboxylic acid components may be 1 or 2 or more.

As the compound contained in any of the tetracarboxylic acid components, a compound providing the structural unit (A-2) is preferable.

The compound providing the structural unit (A-2) may be a compound represented by the formula (a-2), but is not limited thereto, and may be a derivative thereof within a range in which the same structural unit is provided. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-2), and an alkyl ester of the tetracarboxylic acid. As the compound providing the structural unit (A-2), a compound represented by the formula (a-2) (i.e., dianhydride) is preferable.

In the case where the tetracarboxylic acid component contains the compound providing the structural unit (A-1) and the compound providing the structural unit (A-2), the tetracarboxylic acid component preferably contains 50 to 99 mol% of the compound providing the structural unit (A-1), more preferably contains 50 to 95 mol%, still more preferably contains 70 to 95 mol%, particularly preferably contains 85 to 95 mol%, preferably contains 1 to 50 mol% of the compound providing the structural unit (A-2), still more preferably contains 5 to 50 mol%, still more preferably contains 5 to 30 mol%, and particularly preferably contains 5 to 15 mol%.

The tetracarboxylic acid component contains, in total, preferably 50 mol% or more of the compound providing the structural unit (a-1) and the compound providing the structural unit (a-2), more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the total content ratio of the compound providing the structural unit (A-1) and the compound providing the structural unit (A-2) is not particularly limited, that is, 100 mol%. The tetracarboxylic acid component may be composed of only the compound providing the structural unit (A-1) and the compound providing the structural unit (A-2).

The compound for providing the structural unit (B-1), the compound for providing the structural unit (B-2), and the compound for providing the structural unit (B-3) may be a compound represented by the formula (B-1), a compound represented by the formula (B-2), or a compound represented by the formula (B-3), respectively, but the present invention is not limited to these, and may be a derivative thereof within a range where the same structural unit is provided. The derivative includes diisocyanates corresponding to the diamines of the formulae (b-1) to (b-3).

As the compound for providing the structural unit (B-1), the compound for providing the structural unit (B-2), and the compound for providing the structural unit (B-3), a compound represented by the formula (B-1) (i.e., diamine), a compound represented by the formula (B-2) (i.e., diamine), and a compound represented by the formula (B-3) (i.e., diamine), respectively, are preferable.

The diamine component preferably contains 20 to 75 mol% of the compound providing the structural unit (B-1), more preferably contains 25 to 70 mol%, and still more preferably contains 30 to 60 mol%.

The diamine component preferably contains 1 to 25 mol% of the compound providing the structural unit (B-2), more preferably 2 to 20 mol%, and still more preferably 3 to 15 mol%.

The diamine component preferably contains 20 to 75 mol% of the compound providing the structural unit (B-3), more preferably contains 25 to 70 mol%, and still more preferably contains 30 to 60 mol%.

The diamine component preferably contains 50 mol% or more of the compound for providing the structural unit (B-1), the compound for providing the structural unit (B-2), and the compound for providing the structural unit (B-3), more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol% or more in total. The upper limit of the total content ratio of the compound providing the structural unit (B-1), the compound providing the structural unit (B-2), and the compound providing the structural unit (B-3) is not particularly limited, that is, 100 mol%. The diamine component may be composed of only the compound providing the structural unit (B-1), the compound providing the structural unit (B-2), and the compound providing the structural unit (B-3).

The diamine component may contain compounds other than the compound providing the structural unit (B-1), the compound providing the structural unit (B-2), and the compound providing the structural unit (B-3), and examples of the compound include the above aromatic diamine, alicyclic diamine, aliphatic diamine, and derivatives thereof (diisocyanate, etc.).

The number of compounds (i.e., compounds other than the compound providing the structural unit (B-1), the compound providing the structural unit (B-2), and the compound providing the structural unit (B-3)) optionally contained in the diamine component may be 1 or 2 or more.

In the present invention, the ratio of the amount of the tetracarboxylic acid component to the amount of the diamine component to be added used for producing the polyimide resin is preferably 0.9 to 1.1 mol based on 1 mol of the tetracarboxylic acid component.

In the present invention, a blocking agent may be used in addition to the tetracarboxylic acid component and the diamine component in order to produce a polyimide resin. As the blocking agent, monoamines or dicarboxylic acids are preferred. The amount of the blocking agent to be introduced is preferably 0.0001 to 0.1 mol, particularly preferably 0.001 to 0.06 mol, based on 1 mol of the tetracarboxylic acid component. As monoamine type blocking agents, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline and the like are recommended. Among them, benzylamine and aniline can be suitably used. The dicarboxylic acid-based capping agent is preferably a dicarboxylic acid, and a part of the dicarboxylic acid may be closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2, 3-benzophenone dicarboxylic acid, 3, 4-benzophenone dicarboxylic acid, cyclohexane-1, 2-dicarboxylic acid, cyclopentane-1, 2-dicarboxylic acid, 4-cyclohexene-1, 2-dicarboxylic acid, and the like are recommended. Among them, phthalic acid and phthalic anhydride can be suitably used.

The method for reacting the tetracarboxylic acid component with the diamine component is not particularly limited, and a known method can be used.

Specific reaction methods include the following: the method comprises the steps of (1) charging a tetracarboxylic acid component, a diamine component and a reaction solvent into a reactor, stirring at room temperature (about 20 ℃) to 80 ℃ for 0.5 to 30 hours, and then raising the temperature to carry out imidization; the method (2) comprises the steps of adding a diamine component and a reaction solvent to a reactor to dissolve the diamine component and the reaction solvent, adding a tetracarboxylic acid component, stirring the mixture at room temperature (about 20 ℃) to 80 ℃ for 0.5 to 30 hours as required, and heating the mixture to perform imidization; a method (3) wherein a tetracarboxylic acid component, a diamine component, and a reaction solvent are charged into a reactor, and the temperature is immediately raised to carry out imidization; etc.

The reaction solvent used in the production of the polyimide resin may be one which does not interfere with the imidization reaction and which can dissolve the polyimide to be produced. Examples thereof include aprotic solvents, phenolic solvents, ether solvents, and carbonate solvents.

Specific examples of the aprotic solvent include amide solvents such as N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1, 3-dimethylimidazolidone, and tetramethylurea; lactone solvents such as gamma-butyrolactone and gamma-valerolactone; a phosphorus-containing amide solvent such as hexamethylphosphoramide and hexamethylphosphinotricin; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; ketone solvents such as acetone, cyclohexanone, and methylcyclohexanone; amine solvents such as picoline and pyridine; ester solvents such as (2-methoxy-1-methylethyl) acetate, and the like.

Specific examples of the phenol-based solvent include phenol, o-cresol, m-cresol, p-cresol, 2, 3-xylenol, 2, 4-xylenol, 2, 5-xylenol, 2, 6-xylenol, 3, 4-xylenol, and 3, 5-xylenol.

Specific examples of the ether solvent include 1, 2-dimethoxyethane, bis (2-methoxyethyl) ether, 1, 2-bis (2-methoxyethoxy) ethane, bis [ 2- (2-methoxyethoxy) ethyl ] ether, tetrahydrofuran, and 1, 4-dioxane.

Specific examples of the carbonate-based solvent include diethyl carbonate, methylethyl carbonate, ethylene carbonate, propylene carbonate, and the like.

Among the above reaction solvents, an amide-based solvent or a lactone-based solvent is preferable. The reaction solvent may be used alone or in combination of 2 or more kinds.

In the imidization reaction, the reaction is preferably performed while removing water generated during the production, using a dean-stark trap device or the like. By performing such an operation, the polymerization degree and the imidization rate can be further increased.

In the imidization reaction, a known imidization catalyst may be used. Examples of the imidization catalyst include a base catalyst and an acid catalyst.

Examples of the base catalyst include organic base catalysts such as pyridine, quinoline, isoquinoline, α -methylpyridine, β -methylpyridine, 2, 4-dimethylpyridine, 2, 6-dimethylpyridine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N-dimethylaniline, and N, N-diethylaniline, and inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.

Examples of the acid catalyst include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, and the like. The imidization catalyst may be used alone or in combination of 2 or more.

Among the above, from the viewpoint of operability, a base catalyst is preferably used, an organic base catalyst is more preferably used, and triethylamine and triethylenediamine are particularly preferably used in combination.

The temperature of the imidization reaction is preferably 120 to 250 ℃, more preferably 160 to 200 ℃, from the viewpoints of reaction rate, gelation inhibition, and the like. The reaction time is preferably 0.5 to 10 hours after the start of distillation of the produced water.

< crosslinker >

In the present invention, the crosslinker has at least 2 oxazolyl groups. That is, the crosslinking agent in the present invention is a polyfunctional oxazoline compound having 2 or more oxazolyl groups (oxazoline rings) in the molecule.

The oxazolyl group is reactive with the carboxyl group, and if the carboxyl group reacts with the oxazolyl group, an amide bond is formed as shown below. This reaction is particularly easy to carry out if it is heated to 80℃or higher.

Since the polyimide resin contained in the polyimide resin composition of the present invention has a carboxyl group, if the polyimide resin composition of the present invention is heated, the polyimide resins are crosslinked with each other via a crosslinking agent to form a crosslinked polyimide resin. For this reason, the chemical resistance of the film is improved.

The crosslinking agent is not particularly limited as long as it is a polyfunctional oxazoline compound having 2 or more oxazolyl groups in the molecule, and specific examples thereof include 1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene, 1, 4-bis (4, 5-dihydro-2-oxazolyl) benzene, 2' -bis (2-oxazoline), K-2010E, K-2020E, K-2030E manufactured by japan catalyst, ltd, 2, 6-bis (4-isopropyl-2-oxazolin-2-yl) pyridine, 2, 6-bis (4-phenyl-2-oxazolin-2-yl) pyridine, 2' -isopropylidene bis (4-phenyl-2-oxazoline), 2' -isopropylidene bis (4-tert-butyl-2-oxazoline), and the like.

The crosslinking agent preferably contains a compound having an aromatic ring or an aromatic heterocyclic ring bonded with at least 2 oxazolyl groups, more preferably contains a compound having a benzene ring or a pyridine ring bonded with at least 2 oxazolyl groups, still more preferably contains a compound having a benzene ring bonded with at least 2 oxazolyl groups, and particularly preferably 1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene.

The crosslinking agent may be used alone or in combination of 2 or more.

The polyimide resin composition of the present invention preferably contains the polyimide resin and the crosslinking agent in a ratio such that the molar ratio of the oxazolyl group in the crosslinking agent to the carboxyl group in the polyimide resin (oxazolyl/carboxyl group) is in the range of 1/4 to 1/0.5. The above molar ratio is more preferably 1/4 to 1/1, still more preferably 1/2 to 1/1.5, still more preferably 1/2 to 1/1.7.

The molar ratio is calculated based on the amount of the crosslinking agent added and the amount of the compound providing the structural unit (B-1), and is the molar ratio of the oxazolyl group contained in the crosslinking agent to the carboxyl group contained in the compound providing the structural unit (B-1) used in the production of the polyimide resin.

In addition, the polyimide resin composition of the present invention may contain, within a range that does not impair the desired properties of the polyimide film: inorganic filler, adhesion promoter, release agent, flame retardant, ultraviolet stabilizer, surfactant, leveling agent, defoamer, fluorescent brightening agent, cross-linking agent, polymerization initiator, photosensitizer and other additives.

The method for producing the polyimide resin composition of the present invention is not particularly limited, and a known method can be applied.

The polyimide resin composition of the present invention can form a film excellent in colorless transparency, optical isotropy, and chemical resistance. Suitable physical properties of the film which can be formed using the polyimide resin composition of the present invention are as follows.

When a film having a thickness of 10 μm is formed, the total light transmittance is preferably 88% or more, more preferably 90% or more, and still more preferably 91% or more.

When a film having a thickness of 10 μm is formed, the Yellowness Index (YI) is preferably 2.5 or less, more preferably 2.3 or less, and still more preferably 2.0 or less.

B when a film having a thickness of 10 μm is formed ^＊ Preferably 1.5 or less, more preferably 1.2 or less, and still more preferably 1.0 or less.

When a film having a thickness of 10 μm is formed, the haze is preferably 2.0% or less, more preferably 1.0% or less, and still more preferably 0.6% or less.

When a film having a thickness of 10 μm is produced, the absolute value of the thickness retardation (Rth) is preferably 100nm or less, more preferably 90nm or less, and still more preferably 60nm or less.

When a film having a thickness of 10 μm is formed, the mixed acid ΔYI is preferably 1.5 or less, more preferably 1.3 or less, and still more preferably 1.2 or less.

The mixed acid Δyi is a difference between YI before and after immersing the polyimide film in a mixture of phosphoric acid, nitric acid, and acetic acid, and specifically can be measured by the method described in the examples. The smaller Δyi indicates the more excellent acid resistance. By using the polyimide resin composition of the present invention, a film having excellent chemical resistance can be formed, and excellent resistance to acid can be exhibited. Particularly, the composition exhibits excellent resistance to mixed acids (for example, a mixed solution of 50 to 97 mass% of phosphoric acid, 1 to 20 mass% of nitric acid, 1 to 10 mass% of acetic acid and 1 to 20 mass% of water, preferably a mixed solution of 63 to 87 mass% of phosphoric acid, 5 to 15 mass% of nitric acid, 3 to 7 mass% of acetic acid and 5 to 15 mass% of water).

The polyimide resin composition of the present invention can be used to form a film having excellent mechanical properties and heat resistance, and has the following suitable physical properties.

The tensile modulus is preferably 2.0GPa or more, more preferably 2.5GPa or more, and still more preferably 2.7GPa or more.

The tensile strength is preferably 60MPa or more, more preferably 70MPa or more, and still more preferably 80MPa or more.

The tensile elongation at break is preferably 5.0% or more, more preferably 6.0% or more, and still more preferably 7.5% or more.

The glass transition temperature (Tg) is preferably 230℃or higher, more preferably 250℃or higher, still more preferably 290℃or higher.

The physical property values in the present invention can be specifically measured by the methods described in examples.

[ polyimide varnish ]

A suitable embodiment of the polyimide resin composition of the present invention includes a polyimide resin composition (hereinafter, also referred to as "polyimide varnish") which contains an organic solvent in addition to the polyimide resin and the crosslinking agent, and in which the polyimide resin is dissolved in the organic solvent.

That is, the polyimide varnish of the present invention comprises a polyimide resin composition and an organic solvent.

The organic solvent is not particularly limited as long as it dissolves the polyimide resin, and the reaction solvent used in the production of the polyimide resin is preferably used alone or in combination of 2 or more of the above compounds.

Examples of the organic solvent include aprotic solvents, phenol solvents, ether solvents, and carbonate solvents.

Among the above organic solvents, an amide-based solvent or a lactone-based solvent is preferable, and a lactone-based solvent is more preferable from the viewpoint of cleaning properties. Among the lactone-based solvents, gamma-butyrolactone and gamma-valerolactone are preferable, and gamma-butyrolactone is more preferable.

When a lactone solvent is used as the organic solvent, the ratio of the lactone solvent in the organic solvent contained in the polyimide varnish is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, and may be composed of only the lactone solvent.

The lactone-based solvent has a low moisture absorption rate, and therefore, when a film is coated, the varnish does not absorb moisture in the environment, whitening due to precipitation of polyimide is less likely to occur, and the film surface is preferably roughened. In addition, it is preferable to provide a method that can improve the manufacturability without controlling the humidity in the environment.

The organic solvent may be used alone or in combination of 2 or more kinds.

The polyimide varnish may be obtained by adding a crosslinking agent to a solution in which a polyimide resin obtained by a polymerization method is dissolved in a reaction solvent, or may be obtained by adding a diluting solvent and a crosslinking agent to the solution.

The polyimide resin has solvent solubility, and the crosslinking reaction with the crosslinking agent does not substantially proceed at room temperature. Thus, a polyimide varnish stable at room temperature can be formed. The polyimide varnish preferably contains 1 to 40 mass% of the polyimide resin, and more preferably 2 to 40 mass%.

Among them, from the viewpoint of stability, storage at a high concentration, and good film formation, the content is more preferably 5 to 40% by mass, still more preferably 10 to 30% by mass, and still more preferably 15 to 25% by mass. The viscosity of the polyimide varnish is preferably 1 to 200pa·s, more preferably 2 to 100pa·s. The viscosity of the polyimide varnish is a value measured at 25℃using an E-type viscometer.

In addition, when the film is coated, the concentration of the polyimide resin in the polyimide varnish is preferably further reduced, and the polyimide resin is preferably diluted with the organic solvent. The polyimide varnish used for coating the film preferably contains 1 to 10 mass% of the polyimide resin, more preferably 2 to 8 mass%, and even more preferably 4 to 7 mass% from the viewpoint of improving the cleaning performance of the device. The viscosity at this time is preferably 0.1 to 15 Pa.s, more preferably 1 to 10 Pa.s, and still more preferably 2 to 5 Pa.s. By forming the polyimide varnish to have a polyimide resin concentration or viscosity in such a range, the varnish in the apparatus used for film coating with the cleaning liquid can be easily replaced, and the cleaning property can be improved.

[ polyimide film ]

The polyimide film of the present invention is a polyimide film obtained by crosslinking the polyimide resin contained in the polyimide resin composition of the present invention with the crosslinking agent. That is, the polyimide film of the present invention contains a crosslinked polyimide resin which is a crosslinked product of polyimide resins each other via a crosslinking agent. Therefore, the polyimide film of the present invention is excellent in colorless transparency, optical isotropy, and chemical resistance. The polyimide film of the present invention has suitable physical properties as described above.

The method for producing a polyimide film of the present invention is not particularly limited as long as it includes the following steps: the heating is performed at a temperature (preferably 80 ℃ or higher, more preferably 100 ℃ or higher, still more preferably 150 ℃ or higher) at which the crosslinking reaction of the polyimide resin and the crosslinking agent proceeds. For example, the following methods can be mentioned: the polyimide varnish is coated on a smooth support such as a glass plate, a metal plate, or a plastic, or formed into a film, and then heated. By this heat treatment, the crosslinking reaction between the polyimide resin in the polyimide varnish and the crosslinking agent can be performed, and the organic solvent such as the reaction solvent and the diluting solvent contained in the polyimide varnish can be removed.

The coating method includes known coating methods such as spin coating, slot coating, and blade coating.

The heat treatment is preferably performed by evaporating the organic solvent at a temperature of 60 to 150 ℃ to prevent sticking of hands, and then drying the organic solvent at a temperature not lower than the boiling point of the organic solvent used (not particularly limited, preferably 200 to 500 ℃). In addition, the drying is preferably performed under an air atmosphere or a nitrogen atmosphere. The pressure of the drying atmosphere may be reduced, normal pressure or increased.

The method for peeling the polyimide film formed on the support from the support is not particularly limited, and examples thereof include a laser peeling method; a method of using a sacrificial layer for peeling (a method of pre-coating a release agent on the surface of a support) is used.

The thickness of the polyimide film of the present invention may be appropriately selected depending on the application, etc., and is preferably in the range of 1 to 250. Mu.m, more preferably 5 to 100. Mu.m, still more preferably 10 to 80. Mu.m. The thickness is 1 to 250 μm, thereby enabling practical use as a self-standing film.

The thickness of the polyimide film can be easily controlled by adjusting the solid concentration and viscosity of the polyimide varnish.

The polyimide film of the present invention can be suitably used as a film for various members such as color filters, flexible displays, semiconductor components, and optical members. The polyimide film of the present invention is particularly suitable for use as a substrate for image display devices such as liquid crystal displays and OLED displays.

Examples

Hereinafter, the present invention will be specifically described with reference to examples. The present invention is not limited by these examples.

In examples and comparative examples, the physical properties were measured by the methods shown below.

(1) Concentration of solid content

The solid content concentrations of the polyimide resin solution and polyimide varnish were measured as follows: in a small electric furnace "MMF-1" manufactured by AS ONE Corporation, a sample was heated at 320℃for 120 minutes, and the mass difference of the sample before and after heating was calculated.

(2) Film thickness

Film thickness was measured using a micrometer manufactured by Mitutoyo co.

(3) Tensile strength, tensile modulus, tensile elongation at break

Tensile strength, tensile modulus, and tensile elongation at break according to JIS K7127:1999, measured by the tensile tester "Stroggraph VG-1E" manufactured by Toyo Seisakusho Co. The pitch of the chucks was 50mm, the test piece size was 10 mm. Times.70 mm, and the test speed was 20 mm/min.

(4) Glass transition temperature (Tg)

The sample was heated to a sufficient temperature required for removing residual stress under conditions of a sample size of 2mm×20mm, a load of 0.1N, and a heating rate of 10 ℃/min in a tensile mode using a thermo-mechanical analysis apparatus "TMA/SS6100" manufactured by Hitachi High-Tech Science Corporation, the residual stress was removed, and then cooled to room temperature. Thereafter, the elongation of the test piece was measured under the same conditions as in the treatment for removing the residual stress, and the point of inflection of the elongation was found as the glass transition temperature.

(5) Total light transmittance, yellow Index (YI), b ^＊ Haze (haze)

Total light transmittance, YI, b ^＊ And haze according to JIS K7105:1981, a color/turbidity simultaneous measuring instrument "COH400" manufactured by Nippon electric color industry Co., ltd.

(6) Thickness retardation (Rth)

The thickness retardation (Rth) was measured using an ellipsometer "M-220" manufactured by Japanese spectroscopic Co. The thickness phase difference at a wavelength of 590nm was measured. Note that Rth is represented by the following formula, where nx is the largest refractive index in the plane of the polyimide film, ny is the smallest refractive index in the thickness direction, nz is the refractive index, and d is the thickness of the film.

Rth＝[{(nx+ny)/2}-nz]×d

(7) Solvent resistance

At room temperature, a solvent was dropped onto a polyimide film formed on a glass plate, and whether or not the surface of the film was changed was confirmed. Propylene Glycol Monomethyl Ether Acetate (PGMEA) was used as the solvent.

The evaluation criteria for solvent resistance are as follows.

A: the film surface is unchanged.

B: the surface of the film had slightly introduced cracks.

C: cracks are introduced into the film surface, or the film surface dissolves.

(8) Acid resistance (Mixed acid delta YI)

A polyimide film formed on a glass plate was immersed in a mixed acid (H) heated to 40 ℃ ₃ PO ₄ (70 mass%) +HNO ₃ (10 mass%) +CH ₃ COOH (5 mass%) +H ₂ O (15 mass%) for 4 minutes, and then water washing was performed. After washing with water, the water was wiped off, and the mixture was heated on a hot plate at 240℃for 50 minutes to dry. YI was measured before and after the test, and the change (. DELTA.YI) was obtained. The YI measurement was performed in a state where a polyimide film was formed on a glass plate (glass plate+polyimide film state).

(9) Storage stability

The polyimide varnish was stored at room temperature (23 ℃) for 1 week to visually confirm whether Haze (Haze) occurred in the varnish. After 1 week of storage, those who did not exhibit Haze were rated as A, and those who exhibited Haze were rated as C. Specifically, a Haze value of less than 5% was designated as a value where no Haze was found by the same evaluation method as (5), and a Haze value of 5% or more was designated as a value where no Haze was found by the same evaluation method as (5), and a value of C was designated as a value where no Haze was found.

(10) Cleaning property

The Propylene Glycol Monomethyl Ether (PGME) and Propylene Glycol Monomethyl Ether Acetate (PGMEA) were mixed such that the mass ratio of PGME/PGMEA became a mixing ratio of 7/3, to prepare a PGME/PGMEA mixture. The polyimide varnish was mixed with the above PGME/PGMEA mixture to confirm whether or not the mixture was uniformly mixed at room temperature. When the mixture was not uniformly mixed, a precipitate was generated and the mixed solution was clouded, so that the Haze of the mixed solution was measured by the same evaluation method as in (5) Haze, and the cleaning property was evaluated.

The evaluation criteria for the cleaning performance are as follows.

A: the polyimide varnish was uniformly mixed with the PGME/PGMEA mixture. The Haze is 1% or less.

C: the polyimide varnish was not uniformly mixed with the PGME/PGMEA mixture, resulting in a precipitate. The Haze is greater than 1%.

Abbreviations for the tetracarboxylic acid component, diamine component, and crosslinking agent used in examples and comparative examples are as follows.

< tetracarboxylic acid component >

HPMDA:1,2,4, 5-cyclohexane tetracarboxylic dianhydride (Mitsubishi gas chemical Co., ltd.; compound represented by formula (a-1))

6FDA:4,4' - (hexafluoroisopropylidene) diphthalic anhydride (Daikin Industries, manufactured by Ltd.; a compound represented by formula (a-2))

< diamine component >

3,5-DABA:3, 5-diaminobenzoic acid (Compound represented by formula (b-1) of Japanese pure Liang Yak Co., ltd.)

X-22-9409: two terminal amino group-modified silicone oil "X-22-9409" (Compound represented by formula (b-2) manufactured by Xinyue chemical industry Co., ltd.)

6FODA:4,4 '-diamino-2, 2' -bistrifluoromethyl diphenyl ether (ChinaTech Chemical (Tianjin) Co., ltd.; compound represented by formula (b-3))

HFBAPP:2, 2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane (Seika co., ltd.)

TFMB:2,2' -bis (trifluoromethyl) benzidine (Seika Co., ltd.)

< crosslinker >

1,3-PBO:1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene (manufactured by Sanguo pharmaceutical industry Co., ltd.)

Example 1 >

A1L five-necked round-bottomed flask equipped with a stainless steel half-moon shaped stirring blade, a nitrogen inlet pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap was charged with 3,5-DABA8.518g (0.056 mol), X-22-9409 13.09 g (0.010 mol), 6FODA 18.833g (0.056 mol), and gamma-butyrolactone (Mitsubishi chemical Co., ltd.) 66.873g, and the mixture was stirred at a temperature of 70℃in the system under a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution, 27.333g (0.122 mol) of HPDA and 16.718g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added at the same time, and then 0.617g of triethylamine (Kanto chemical Co., ltd.) as an imidization catalyst was added thereto, and the mixture was heated in a covered heater to raise the temperature in the reaction system to 190℃over about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 172.409g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (1) having a solid content of 20% by mass.

Then, to 200g of the polyimide resin solution (1), 3.784g (0.0175 mol) of 1,3-pbo as a crosslinking agent was added, and the mixture was stirred at room temperature for 1 hour to obtain a polyimide varnish containing the crosslinking agent and the polyimide resin in a solid content concentration of 19.6 mass%. The molar ratio of oxazolyl group/carboxyl group calculated based on the addition amount of 1,3-PBO and the addition amount of 3,5-DABA was 1/2.

Then, the obtained polyimide varnish was spin-coated on a glass plate, and kept at 80 ℃ for 20 minutes on a hot plate, and then heated at 260 ℃ for 30 minutes in an air atmosphere in a hot air dryer, and the solvent was evaporated to obtain a thin film. The results are shown in Table 1.

Example 2 >

A1L five-necked round-bottomed flask equipped with a stainless steel half-moon shaped stirring blade, a nitrogen inlet pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap was charged with 8.173g (0.054 mol) of 3,5-DABA, 13.155g (0.010 mol) of X-22-9409, 18.071g (0.054 mol) of 6FODA, and 66.699g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) and stirred at a temperature of 70℃in the system under a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution, 23.605g (0.105 mol) of HPMDA and 8.338g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added simultaneously, and after stirring was continued for 10 minutes, 5.211g (0.012 mol) of 6FDA and 8.338g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added simultaneously, and after adding 0.617g of triethylamine (Kanto chemical Co., ltd.) as an imidization catalyst, heating was performed in a covered heater, and the temperature in the reaction system was raised to 190℃for about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 172.626g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (2) having a solid content of 20.0% by mass.

Then, 200g of 1,3-PBO3.655g (0.0169 mol) as a crosslinking agent was added to 200g of the polyimide resin solution (2), and the mixture was stirred at room temperature for 1 hour to obtain a polyimide varnish containing the crosslinking agent and the polyimide resin and having a solid content concentration of 19.6 mass%. The molar ratio of oxazolyl group/carboxyl group calculated based on the addition amount of 1,3-PBO and the addition amount of 3,5-DABA was 1/2.

Comparative example 1 >

A1L five-necked round-bottomed flask equipped with a stainless steel half-moon shaped stirring blade, a nitrogen inlet pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap was charged with 28.245 g (0.188 mol) of 3,5-DABA and 84.928g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) and stirred at a temperature of 70℃in the system under a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution, 42.149g (0.188 mol) of HPDA and 21.232g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added simultaneously, and then 0.951g of triethylamine (Kanto chemical Co., ltd.) as an imidization catalyst was added thereto, and the mixture was heated in a covered heater to raise the temperature in the reaction system to 190℃over about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 149.840g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (3) having a solid content of 20% by mass.

Then, to 200g of the polyimide resin solution (3), 12.704g (0.059 mol) of 1,3-pbo as a crosslinking agent was added, and after stirring at room temperature for 1 hour, a polyimide varnish containing the crosslinking agent and the polyimide resin in a solid content concentration of 19.6 mass% was obtained. After that, the polyimide varnish was left to stand at room temperature, and as a result, white precipitate was formed in the polyimide varnish, and the fluidity of the polyimide varnish disappeared. Therefore, it is difficult to thin the film. The molar ratio of oxazolyl group/carboxyl group calculated based on the addition amount of 1,3-PBO and the addition amount of 3,5-DABA was 1/2.

Comparative example 2 >

Into a 1L five-necked round-bottom flask equipped with a stainless steel half-moon shaped stirring blade, a nitrogen gas introduction pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap were charged 6FODA41.034g (0.122 mol) and 82.073g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) and stirred at a temperature of 70℃in the system under a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution, 27.361g (0.122 mol) of HPDA and 20.518g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added at the same time, and then 0.617g of triethylamine (Kanto chemical Co., ltd.) as an imidization catalyst was added thereto, and the mixture was heated in a covered heater to raise the temperature in the reaction system to 190℃over about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 153.408g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (4) having a solid content of 20% by mass.

The polyimide resin solution (4) was used as a polyimide varnish without adding a crosslinking agent 1, 3-PBO. That is, the obtained polyimide varnish (polyimide resin solution (4)) was spin-coated on a glass plate, kept at 80 ℃ for 20 minutes on a hot plate, and then heated at 260 ℃ for 30 minutes in a hot air dryer under an air atmosphere, whereby the solvent was evaporated to obtain a film. The results are shown in Table 1.

Comparative example 3 >

To a 1L five-necked round-bottom flask equipped with a stainless steel half-moon shaped stirring blade, a nitrogen inlet pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap were charged TFMB24.160g (0.075 mol), 3,5-DABA 11.478g (0.075 mol), and gamma-butyrolactone (Mitsubishi chemical Co., ltd.) 83.318g, and the mixture was stirred at a temperature of 70℃in the system under a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution, 33.794g (0.151 mol) of HPDA and 20.830g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added at the same time, and then 0.763g of triethylamine (Kanto chemical Co., ltd.) as an imidization catalyst was added thereto, and the mixture was heated in a covered heater to raise the temperature in the reaction system to 190℃over about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 151.852g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (5) having a solid content of 20% by mass.

Then, to 200g of the polyimide resin solution (5), 5.069g (0.023 mol) of 1,3-pbo as a crosslinking agent was added, and the mixture was stirred at room temperature for 1 hour to obtain a polyimide varnish containing the crosslinking agent and the polyimide resin in a solid content concentration of 19.5 mass%. The molar ratio of oxazolyl group/carboxyl group calculated based on the addition amount of 1,3-PBO and the addition amount of 3,5-DABA was 1/2.

Comparative example 4 >

Into a 1L five-necked round-bottom flask equipped with a stainless steel half-moon shaped stirring blade, a nitrogen inlet pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap were charged 6FODA24.894g (0.074 mol), 3,5-DABA 11.266g (0.074 mol), and gamma-butyrolactone (Mitsubishi chemical Co., ltd.) 83.198g, and the mixture was stirred at a temperature of 70℃in the system under a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution, 33.172g (0.148 mol) of HPDA and 20.800g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added at the same time, and then 0.749g of triethylamine (Kanto chemical Co., ltd.) as an imidization catalyst was added, and the mixture was heated in a covered heater to raise the temperature in the reaction system to 190℃over about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 152.002g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (6) having a solid content of 20% by mass.

Then, 5.000g (0.023 mol) of 1,3-PBO as a crosslinking agent was added to 200g of the polyimide resin solution (6), and the mixture was stirred at room temperature for 1 hour to obtain a polyimide varnish containing the crosslinking agent and the polyimide resin in a solid content concentration of 19.5 mass%. The molar ratio of oxazolyl group/carboxyl group calculated based on the addition amount of 1,3-PBO and the addition amount of 3,5-DABA was 1/2.

Comparative example 5 >

3,5-DABA6.994g (0.046 mol), X-22-9409 g (0.010 mol), HFBAPP 23.951g (0.046 mol) and gamma-butyrolactone (Mitsubishi chemical Co., ltd.) 65.994g were charged into a 1L five-necked round-bottom flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap, and stirred at a nitrogen atmosphere and a rotation speed of 200rpm at a temperature of 70℃in the system to obtain a solution.

To this solution, 22.861g (0.102 mol) of HPDA and 16.498g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added simultaneously, and then 0.516g of triethylamine (Kato chemical Co., ltd.) and 0.057g of tetraethylene diamine (Tokyo chemical Co., ltd.) as imidization catalysts were added, and the mixture was heated in a covered heater to raise the temperature in the reaction system to 190℃for about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 173.51g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (7) having a solid content of 20% by mass.

Then, 200g of 1,3-PBO3.784g (0.0175 mol) as a crosslinking agent was added to 200g of the polyimide resin solution (7), and the mixture was stirred at room temperature for 1 hour to obtain a polyimide varnish containing the crosslinking agent and the polyimide resin in a solid content concentration of 19.6 mass%. The molar ratio of oxazolyl group/carboxyl group calculated based on the addition amount of 1,3-PBO and the addition amount of 3,5-DABA was 1/2.

Comparative example 6 >

A1L five-necked round-bottomed flask equipped with a stainless steel half-moon shaped stirring blade, a nitrogen inlet pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap was charged with 3,5-DABA8.640g (0.057 mol), X-22-9409 13.906g (0.010 mol), TFMB 18.861g (0.056 mol), and gamma-butyrolactone (Mitsubishi chemical Co., ltd.) 66.934g, and the mixture was stirred at a temperature of 70℃in the system under a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution, 27.724g (0.124 mol) of HPDA and 16.734g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added simultaneously, and then 0.625g of triethylamine (Kanto chemical Co., ltd.) as an imidization catalyst was added thereto, and the mixture was heated in a covered heater to raise the temperature in the reaction system to 190℃over about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 172.332g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (8) having a solid content of 20% by mass.

Then, 200g (0.0178 mol) of 1,3-PBO3.853g (as a crosslinking agent) was added to the polyimide resin solution (8), and the mixture was stirred at room temperature for 1 hour to obtain a polyimide varnish having a solid content concentration of 19.6 mass% including the crosslinking agent and the polyimide resin. The molar ratio of oxazolyl group/carboxyl group calculated based on the addition amount of 1,3-PBO and the addition amount of 3,5-DABA was 1/2.

Comparative example 7 >

A1L five-necked round-bottomed flask equipped with a stainless steel half-moon shaped stirring blade, a nitrogen inlet pipe, a dean-Stark trap equipped with a condenser, a thermometer, and a glass end cap was charged with 8.183g (0.054 mol) of 3,5-DABA, 13.859g (0.010 mol) of X-22-9409, 17.224g (0.054 mol) of TFMB, and 66.721g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) and stirred at a temperature of 70℃in the system under a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution, 23.733g (0.106 mol) of HPMDA and 8.340g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added simultaneously, and after stirring for 10 minutes, 5.399 g (0.012 mol) of 6FDA and 8.340g of gamma-butyrolactone (Mitsubishi chemical Co., ltd.) were added simultaneously, and after adding 0.595g of triethylamine (Kanto chemical Co., ltd.) as an imidization catalyst, heating was performed in a covered heater, and the temperature in the reaction system was raised to 190℃for about 20 minutes. The distilled components were collected, the rotation speed was adjusted according to the viscosity increase, and the temperature in the reaction system was kept at 190℃for about 5 hours for reflux.

Then, 172.598g of γ -butyrolactone (Mitsubishi chemical corporation) was added, the temperature in the reaction system was cooled to 120℃and then stirred for about 3 hours to homogenize the mixture, thereby obtaining a polyimide resin solution (9) having a solid content of 20% by mass.

Then, 200g (0.0169 mol) of 1,3-PBO3.650g (as a crosslinking agent) was added to the polyimide resin solution (9), and the mixture was stirred at room temperature for 1 hour to obtain a polyimide varnish containing the crosslinking agent and the polyimide resin in a solid content concentration of 19.6 mass%. The molar ratio of oxazolyl group/carboxyl group calculated based on the addition amount of 1,3-PBO and the addition amount of 3,5-DABA was 1/2.

TABLE 1

As shown in table 1, the polyimide films of examples 1 and 2 were excellent in colorless transparency, optical isotropy, and chemical resistance (solvent resistance and acid resistance), and the polyimide varnishes of examples 1 and 2 were excellent in storage stability and cleaning property.

On the other hand, in comparative example 1, a polyimide varnish was obtained by adding a crosslinking agent to a polyimide resin solution and stirring for 1 hour, and then, the polyimide varnish was left to stand at room temperature, so that white precipitate was generated in the polyimide varnish, and fluidity of the polyimide varnish was lost. That is, the polyimide varnish of comparative example 1 was inferior in storage stability and cleaning property.

The polyimide film of comparative example 2 was poor in solvent resistance. In addition, the value of ΔYI of the mixed acid is as large as 1.57, and the acid resistance is also poor.

The polyimide film of comparative example 3 was poor in optical isotropy. In addition, the polyimide varnish of comparative example 3 was poor in cleaning property.

The polyimide varnish of comparative example 4 was poor in detergency.

The polyimide film of comparative example 5 has good solvent resistance. In addition, the polyimide varnish of comparative example 5 was poor in detergency.

The polyimide varnish of comparative example 6 was inferior in storage stability and cleaning property.

The polyimide varnish of comparative example 7 was poor in detergency.

Claims

1. A polyimide resin composition comprising a polyimide resin and a crosslinking agent having at least 2 oxazolyl groups,

the structural unit B comprises: a structural unit (B-1) derived from a compound represented by the following formula (B-1), a structural unit (B-2) derived from a compound represented by the following formula (B-2), and a structural unit (B-3) derived from a compound represented by the following formula (B-3),

the ratio of the structural unit (A-1) in the structural unit A is 85 mol% or more,

the ratio of the structural unit (B-3) in the structural unit B is 20 to 75 mol%,

The total ratio of the structural units (B-1) to (B-3) in the structural unit B is 90 mol% or more,

the molar ratio of the oxazolyl in the cross-linking agent to the carboxyl in the polyimide resin, namely that the oxazolyl/carboxyl is 1/4-1/0.5,

in the formula (b-1), the amino acid sequence,

p is an integer of 0 to 2,

m1 is an integer of 0 to 4,

m2 is an integer of 0 to 4,

in the formula (b-1-i), m3 is an integer of 0 to 5, in the formula (b-1-ii), m4 is an integer of 0 to 5,

wherein,

m1+m2+m3+m4 is 1 or more,

when p is 0, m1 is an integer of 1 to 4,

when p is 2, 2X and 2 m2 to m4 are independently selected;

in the formula (b-2), the amino acid sequence,

r is a positive integer.

2. The polyimide resin composition according to claim 1, wherein the structural unit (B-1) is a structural unit (B-11) derived from a compound represented by the following formula (B-11),

3. the polyimide resin composition according to claim 1 or 2, wherein the crosslinking agent is: a compound comprising an aromatic ring or an aromatic heterocyclic ring to which at least 2 oxazolyl groups are bonded.

4. The polyimide resin composition according to claim 3, wherein the crosslinking agent is: a compound comprising a benzene ring bonded with at least 2 oxazolyl groups.

5. The polyimide resin composition according to claim 4, wherein the crosslinking agent is 1, 3-bis (4, 5-dihydro-2-oxazolyl) benzene.

6. The polyimide resin composition according to claim 1 or 2, wherein the structural unit a further comprises: a structural unit (A-2) derived from a compound represented by the following formula (a-2),

7. the polyimide resin composition according to claim 6, wherein,

the ratio of the structural unit (A-1) in the structural unit A is 85 to 99 mol%,

the ratio of the structural unit (A-2) in the structural unit A is 1 to 15 mol%.

8. A polyimide varnish, comprising: the polyimide resin composition according to any one of claims 1 to 7, and an organic solvent.

9. A polyimide film obtained by crosslinking the polyimide resin in the polyimide resin composition according to any one of claims 1 to 7 with the crosslinking agent.