WO2020040057A1

WO2020040057A1 - Polyimide resin, polyimide varnish, and polyimide film

Info

Publication number: WO2020040057A1
Application number: PCT/JP2019/032153
Authority: WO
Inventors: 晃久松丸; 重之廣瀬; 智寿村山; 孝博村谷
Original assignee: 三菱瓦斯化学株式会社
Priority date: 2018-08-24
Filing date: 2019-08-16
Publication date: 2020-02-27
Also published as: JPWO2020040057A1; JP7463964B2; CN112601777A; CN112601777B; KR20210047858A; TW202014448A

Abstract

The present invention relates to a polyimide resin that comprises a constituent unit A derived from tetracarboxylic acid dianhydride and a constituent unit B derived from diamine, wherein the constituent unit A contains at least one constituent unit selected from the group consisting of a constituent unit (A-1) derived from a compound represented by formula (a-1) and a constituent unit (A-2) derived from a compound represented by formula (a-2), and the constituent unit B contains at least one constituent unit (B-1) selected from the group consisting of a constituent unit derived from a compound represented by general formula (b1-1) and a constituent unit derived from a compound represented by general formula (b2-1). Provided are a polyimide resin that can form a highly transparent and colorless film that exhibits a low retardation; a polyimide varnish; and a polyimide film. (In the formulas, X¹ to X⁴ each independently represent a single bond, an alkylene group having 1 to 5 carbons, an alkylidene group having 2 to 5 carbons, -S-, -SO-, -SO₂-, -O-, or -CO-.)

Description

Polyimide resin, polyimide varnish and polyimide film

(4) The present invention relates to a polyimide resin, a polyimide varnish, and a polyimide film.

Various uses of polyimide resins are being studied in the fields of electric and electronic parts. For example, it is desired to replace a glass substrate used for an image display device such as a liquid crystal display or an OLED display with a plastic substrate for the purpose of reducing the weight and flexibility of the device. Research is ongoing. Polyimide films for such uses are required to be colorless and transparent.
Further, as the required characteristics of the polyimide film, it is required that the retardation due to birefringence is small and the retardation is low.

Patent Document 1 discloses that a polyimide resin which gives a film with reduced birefringence is obtained by using a diamine (for example, metaphenylenediamine) in which at least one of amino groups of the diamine is bonded to a meta position with respect to a main chain. Is disclosed.
Patent Document 2 discloses, as a polyimide resin that gives a film excellent in heat resistance, transmittance, low linear expansion coefficient and low retardation, a tetracarboxylic acid residue and a diamine residue having a specific structure, and a tetracarboxylic residue having a bent portion. Disclosed are polyimide resins containing groups and / or diamine residues, specifically 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-bicyclohexane A polyimide resin obtained using tetracarboxylic dianhydride, pyromellitic anhydride, 2,2'-bis (trifluoromethyl) benzidine, and 4,4'-diaminodiphenyl sulfone is disclosed.

JP-A-8-134211 International Publication No. WO 2015/125895

As described above, various characteristics are required for the polyimide film, but it is not easy to satisfy these characteristics simultaneously.
The present invention has been made in view of such a situation, and an object of the present invention is to provide a polyimide resin that is excellent in colorless transparency and that can form a film with low retardation, and a polyimide varnish containing the polyimide resin. And a polyimide film.

(4) The present inventors have found that a polyimide resin containing a combination of specific structural units can solve the above-mentioned problems, and have completed the invention.

That is, the present invention relates to the following [1] to [9].
[1]
A polyimide resin having a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine,
The structural unit A is a structural unit (A-1) derived from a compound represented by the following formula (a-1) and a structural unit (A-2) derived from a compound represented by the following formula (a-2) ) Comprising at least one structural unit selected from the group consisting of
The structural unit B is at least selected from the group consisting of a structural unit derived from a compound represented by the following general formula (b1-1) and a structural unit derived from a compound represented by the following general formula (b2-1). A polyimide resin containing one structural unit (B-1).

(Wherein X ¹ to X ⁴ are each independently a single bond, an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, —S—, —SO—, —SO ₂ —, —O -Or -CO-.)

[2]
The polyimide resin according to the above [1], wherein the ratio of the structural unit (B-1) in the structural unit B is 5 to 100 mol%.
[3]
The polyimide resin according to the above [1] or [2], wherein the structural unit A includes the structural unit (A-1), and the ratio of the structural unit (A-1) in the structural unit A is 45 to 100 mol%. .
[4]
Wherein the structural unit (B-1) is a structural unit derived from a compound represented by the following formula (b1-1-1), a structural unit derived from a compound represented by the following formula (b1-1-2), and The polyimide resin according to any one of the above [1] to [3], comprising at least one structural unit selected from the group consisting of structural units derived from a compound represented by the following formula (b1-1-3).

[5]
The structural unit B further includes 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) ) And at least one structural unit selected from the group consisting of structural units (B-4) derived from a compound represented by the following formula (b-4): The polyimide resin according to the above.

[6]
The above-mentioned [5], wherein the ratio of the total of the structural units (B-2), (B-3) and (B-4) in the structural unit B is 5 to 95 mol%. Polyimide resin.
[7]
The polyimide resin according to any one of the above [1] to [6], wherein the structural unit A further includes a structural unit (A-3) derived from a compound represented by the following formula (a-3).

[8]
A polyimide varnish obtained by dissolving the polyimide resin according to any one of the above [1] to [7] in an organic solvent.
[9]
A polyimide film containing the polyimide resin according to any one of the above [1] to [7].

According to the present invention, it is possible to provide a polyimide resin which is excellent in colorless transparency and can form a film having further low retardation, and a polyimide varnish and a polyimide film containing the polyimide resin.

[Polyimide resin]
The polyimide resin of the present invention has a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine, and the structural unit A is derived from a compound represented by the following formula (a-1). At least one structural unit selected from the group consisting of a structural unit (A-1) and a structural unit (A-2) derived from a compound represented by the following formula (a-2):
The structural unit B is at least selected from the group consisting of a structural unit derived from a compound represented by the following general formula (b1-1) and a structural unit derived from a compound represented by the following general formula (b2-1). Contains one structural unit (B-1).

<Structural unit A>
The structural unit A is a structural unit derived from tetracarboxylic dianhydride in the polyimide resin, and the structural unit A is a structural unit (A-1) derived from a compound represented by the following formula (a-1). ) And at least one structural unit selected from the group consisting of structural units (A-2) derived from a compound represented by the following formula (a-2).

The compound represented by the formula (a-1) is 1,2,4,5-cyclohexanetetracarboxylic dianhydride.
When the structural unit A contains the structural unit (A-1), the film has improved colorless transparency, heat resistance, and thermal stability.
The compound represented by the formula (a-2) is 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride.
When the structural unit A contains the structural unit (A-2), the transparency of the film is improved, and the solubility of the polyimide in an organic solvent is improved.

The structural unit A may include both the structural unit (A-1) and the structural unit (A-2), but preferably the structural unit (A-1) or the structural unit (A-2) Any one of them, more preferably the structural unit (A-1).

When the structural unit A includes the structural unit (A-1) and the structural unit (A-2), the total ratio of the structural units (A-1) and (A-2) in the structural unit A is preferably 50. It is at least 70 mol%, more preferably at least 70 mol%, even more preferably at least 90 mol%, particularly preferably at least 99 mol%. The upper limit of the total ratio of the structural units (A-1) and (A-2) is not particularly limited, that is, 100 mol%.

When the structural unit A includes the structural unit (A-1), the ratio of the structural unit (A-1) in the structural unit A is preferably 45 mol% or more, more preferably 70 mol% or more, and further preferably 90 mol% or more. Mol% or more, particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, that is, 100 mol%. Similarly, the ratio of the structural unit (A-1) in the structural unit A is preferably from 45 to 100 mol%, more preferably from 70 to 100 mol%, further preferably from 90 to 100 mol%, particularly preferably from 99 to 100 mol%. 100 mol%.
When the structural unit A includes the structural unit (A-2), the ratio of the structural unit (A-2) in the structural unit A is preferably 45 mol% or more, more preferably 70 mol% or more, and further preferably 90 mol% or more. Mol% or more, particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited, that is, 100 mol%. Similarly, the ratio of the structural unit (A-2) in the structural unit A is preferably from 45 to 100% by mole, more preferably from 70 to 100% by mole, still more preferably from 90 to 100% by mole, and particularly preferably from 99 to 100% by mole. 100 mol%.

The structural unit A may further include a structural unit (A-3) derived from a compound represented by the following formula (a-3).

The compound represented by the formula (a-3) is: norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid It is an acid dianhydride. When the structural unit A contains the structural unit (A-3), the colorless transparency of the film is improved.

When the structural unit A includes the structural unit (A-3), the ratio of the structural unit (A-13) in the structural unit A is preferably 55 mol% or less, more preferably 30 mol% or less.
When the structural unit A includes the structural unit (A-3), the structural unit A preferably includes the structural unit (A-1) and the structural unit (A-3), and more preferably the structural unit (A-1) And the structural unit (A-3).

The structural unit A may include structural units other than the structural units (A-1) to (A-3) as long as the effects of the present invention are not impaired. The tetracarboxylic dianhydride that gives such a constitutional unit is not particularly limited, but pyromellitic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3 ', 4 Aromatics such as 4'-biphenyltetracarboxylic dianhydride, 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride and 2,2', 3,3'-biphenyltetracarboxylic dianhydride Tetracarboxylic dianhydride; 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclopentanetetracarboxylic dianhydride, bicyclo [2.2.2] octa- 7-en-2,3,5 Alicyclic tetracarboxylic dianhydrides such as 1,6-tetracarboxylic dianhydride and dicyclohexyltetracarboxylic dianhydride; and aliphatic such as 1,2,3,4-butanetetracarboxylic dianhydride And tetracarboxylic dianhydride.
In this specification, aromatic tetracarboxylic dianhydride means tetracarboxylic dianhydride containing one or more aromatic rings, and alicyclic tetracarboxylic dianhydride means one alicyclic ring. The tetracarboxylic dianhydride containing the above and containing no aromatic ring is meant, and the aliphatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing neither an aromatic ring nor an alicyclic ring.
The structural unit other than the structural units (A-1) to (A-3) arbitrarily included in the structural unit A may be one type or two or more types.
It is preferable that the structural unit A does not include a structural unit other than the structural units (A-1) to (A-3).

<Structural unit B>
Structural unit B is a structural unit derived from a diamine in the polyimide resin, and is represented by a structural unit derived from a compound represented by the following general formula (b1-1), and represented by the following general formula (b2-1) At least one structural unit (B-1) selected from the group consisting of structural units derived from compounds.

In the formulas (b1-1) and (b2-1), X ¹ to X ⁴ each independently represent a single bond, an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, —S—, — Represents SO—, —SO ₂ —, —O—, or —CO—.
When the structural unit B contains the structural unit (B-1), the colorless transparency of the film is improved, and the retardation value is reduced. The structural unit (B-1) may be one type or two or more types.

The compound represented by general formula (b1-1) are connected three benzene ring via the ^{X 1} and ^{X 2,} the ^{backbone X 1} and ^{X 2} are bonded to the 1- and 3-positions of the central benzene ring a compound represented by the general formula (b2-1), via the ^{X 3} and ^{X 4} are connected three benzene rings, ^{X 3} and ^{X 4} is bonded to the 1,2-position of the central benzene ring It has a modified skeleton. By having such a skeleton structure in the structural unit B of the polyimide resin, it is possible to form a film having excellent low retardation.

X ¹ to X ⁴ in the general formulas (b1-1) and (b2-1) each independently preferably represent an alkylidene group having 3 to 5 carbon atoms, from the viewpoint of forming a film excellent in low retardation, Represents _2- or -O-, more preferably represents an alkylidene group having 3 to 5 carbon atoms, or -O-, further preferably represents an isopropylidene group or -O-, and still more preferably represents an isopropylidene group. Is shown.
X ¹ and X ² in the general formula (b1-1) may each have a different group, but are preferably the same group. Similarly, X ³ and X ⁴ in the formula (b2-1) may each have a different group, but are preferably the same group.
The amino group in the general formulas (b1-1) and (b2-1) may be located at the para position or the meta position of the benzene ring with respect to any of X ¹ to X ⁴ bonded to the benzene ring to which each amino group is bonded. It is preferable to bond to the position.

The structural unit (B-1) preferably contains a structural unit derived from the compound represented by the general formula (b1-1), and is derived from a compound represented by the following formula (b1-1-1) At least one selected from the group consisting of a structural unit, a structural unit derived from a compound represented by the following formula (b1-1-2), and a structural unit derived from a compound represented by the following formula (b1-1-3) More preferably, it contains one structural unit.

The compound represented by the formula (b1-1-1) is 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene,
The compound represented by the formula (b1-1-2) is 1,3-bis (4-aminophenoxy) benzene,
The compound represented by the formula (b1-1-3) is 1,3-bis (3-aminophenoxy) benzene.

Among the compounds represented by the formulas (b1-1-1) to (b1-1-3), the compound represented by the formula (b1-1-1) and the compound represented by the formula (b1-1-2) are preferable. And at least one compound selected from the group consisting of compounds represented by formula (b), and more preferably a compound represented by formula (b1-1-1).

The ratio of the structural unit (B-1) in the structural unit B is preferably at least 5 mol%, more preferably at least 15 mol%, further preferably at least 45 mol%, particularly preferably at least 75 mol%. The upper limit of the ratio of the structural unit (B-1) is not particularly limited, that is, 100 mol%. The structural unit B may be composed of only the structural unit (B-1).
The ratio of the structural unit (B-1) in the structural unit B is preferably 5 to 100 mol%, more preferably 15 to 100 mol%, further preferably 45 to 100 mol%, and particularly preferably 75 to 100 mol%. It is.
When the structural unit (B-1) includes a structural unit derived from the compound represented by the formula (b1-1-1), it is represented by the formula (b1-1-1) in the structural unit (B-1). The ratio of the structural units derived from the compound is preferably 50 to 100 mol%, more preferably 75 to 100 mol%, further preferably 90 to 100 mol%, and particularly preferably 95 to 100 mol%.

The structural unit B may include a structural unit other than the structural unit (B-1). Such a structural unit is not particularly limited, but may be a structural unit (B-2) derived from a compound represented by the following formula (b-2), or a structural unit derived from a compound represented by the following formula (b-3) It is preferable to include at least one structural unit selected from the group consisting of the structural unit (B-3) and a structural unit (B-4) derived from a compound represented by the following formula (b-4).

The compound represented by the formula (b-2) is 2,2-bis [4- (4-aminophenoxy) phenyl] propane,
The compound represented by the formula (b-3) is 4,4′-diaminodiphenyl ether,
The compound represented by the formula (b-4) is 1,4-bis [2- (4-aminophenyl) -2-propyl] benzene.
When the structural unit B contains at least one structural unit selected from the group consisting of the structural units (B-2) to (B-4), two or more of the structural units (B-2) to (B-4) May be included, but it is preferable to include one of the structural units (B-2) to (B-4). That is, it is preferable that the structural unit B includes the structural unit (B-2), the structural unit (B-3), or the structural unit (B-4).

When the structural unit B includes at least one structural unit selected from the group consisting of the structural units (B-2) to (B-4), the structural units (B-2) to (B-4) in the structural unit B Is preferably 5 to 95 mol%, more preferably 7 to 85 mol%, further preferably 10 to 55 mol%, and particularly preferably 12 to 25 mol%.

The structural unit B may include structural units other than the structural units (B-1) to (B-4). The diamine providing such a structural unit is not particularly limited, but includes 1,4-phenylenediamine, p-xylylenediamine, 3,5-diaminobenzoic acid, 1,5-diaminonaphthalene, 2,2′-dimethyl Biphenyl-4,4'-diamine, 2,2'-bis (trifluoromethyl) benzidine, 4,4'-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4'- Diaminodiphenyl sulfone, 4,4'-diaminobenzanilide, 3,4'-diaminodiphenyl ether, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-5 Amine, N, N'-bis (4-aminophenyl) terephthalamide, 4,4'-bis (4-aminophenoxy) biphenyl, 2,2 Bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane and 9,9-bis (4-aminophenyl) fluorene, Aromatic diamines such as 4-bis (4-aminophenoxy) benzene; alicyclic diamines such as 1,3-bis (aminomethyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane; and ethylenediamine and hexamethylenediamine And the like.
In the present specification, aromatic diamine means a diamine containing one or more aromatic rings, and alicyclic diamine means a diamine containing one or more alicyclic rings and not containing an aromatic ring. The aromatic diamine means a diamine containing neither an aromatic ring nor an alicyclic ring.
The structural unit other than the structural units (B-1) to (B-4) arbitrarily included in the structural unit B may be one type or two or more types.
It is preferable that the structural unit B does not include a structural unit other than the structural units (B-1) to (B-4).

数 The polyimide resin of the present invention preferably has a number average molecular weight of 5,000 to 100,000 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 value measured by gel filtration chromatography.

The polyimide resin of the present invention may include a structure other than a polyimide chain (a structure in which the structural unit A and the structural unit B are imide-bonded). Examples of the structure other than the polyimide chain that can be included in the polyimide resin include a structure including an amide bond.
The polyimide resin of the present invention preferably contains a polyimide chain (a structure in which the structural unit A and the structural unit B are imide-bonded) as a main structure. Therefore, the proportion of the polyimide chain in the polyimide resin of the present invention is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 90% by mass or more, and particularly preferably 99% by mass or more. % Or more.

By using the polyimide resin of the present invention, a film having excellent colorless transparency and low retardation can be formed, and preferable physical properties of the film are as follows.
The total light transmittance of a film having a thickness of 30 μm is preferably 85% or more, more preferably 87% or more, further preferably 88% or more, and still more preferably 89% or more.
The haze of the film having a thickness of 30 μm is preferably 2.0% or less, more preferably 1.5% or less, and further preferably 1.0% or less.
The yellow index (YI) of the film having a thickness of 30 μm is preferably 4.0 or less, more preferably 3.5 or less, still more preferably 3.0 or less, and even more preferably 2.0 or less. It is as follows.
In the present invention, a polyimide film having a thickness retardation (Rth) of preferably 90 nm or less, more preferably 70 nm or less, further preferably 50 nm or less, and still more preferably 30 nm or less can be obtained. In this specification, “low retardation” means that the thickness retardation (Rth) is low, and preferably that the thickness retardation (Rth) is within the above range.
In addition, the above-mentioned physical property values in the present invention can be specifically measured by the methods described in Examples.

The film that can be formed by using the polyimide resin of the present invention has good heat resistance and mechanical properties, and has the following preferable physical properties.
The glass transition temperature (Tg) is preferably 200 ° C. or higher, more preferably 230 ° C. or higher, and further preferably 250 ° C. or higher.
The tensile modulus is preferably 2.5 GPa or more, more preferably 3.0 GPa or more, and still more preferably 3.5 GPa or more.
The tensile strength is preferably at least 70 MPa, more preferably at least 90 MPa, even more preferably at least 100 MPa.
The tensile modulus and the tensile strength are values measured according to JIS K7127: 1999.

[Production method of polyimide resin]
The polyimide resin of the present invention comprises: a tetracarboxylic acid component containing at least one selected from the group consisting of a compound providing the above-mentioned structural unit (A-1) and a compound giving the above-mentioned structural unit (A-2); By reacting with a diamine component containing a compound giving the structural unit (B-1).

Examples of the compound providing the structural unit (A-1) include a compound represented by the formula (a-1), but are not limited thereto, and may be a derivative thereof as long as 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) and an alkyl ester of the tetracarboxylic acid. As the compound giving the structural unit (A-1), a compound represented by the formula (a-1) (that is, a dianhydride) is preferable.
Similarly, the compound providing the structural unit (A-2) includes a compound represented by the formula (a-2), but is not limited thereto, and may be a derivative thereof as long as 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 giving the structural unit (A-2), a compound represented by the formula (a-2) (that is, a dianhydride) is preferable.

The tetracarboxylic acid component contains the compound giving the structural unit (A-1) and the compound giving the structural unit (A-2) in total, preferably at least 50 mol%, more preferably at least 70 mol%, even more preferably. Is at least 90 mol%, particularly preferably at least 99 mol%. The upper limit of the total content 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 consist of only the compound giving the structural unit (A-1) and the compound giving the structural unit (A-2).

When the tetracarboxylic acid component contains a compound giving the structural unit (A-1) or a compound giving the structural unit (A-2), the compound giving the structural unit (A-1) or the structural unit (A-2) ) Is contained in an amount of preferably at least 45 mol%, more preferably at least 70 mol%, even more preferably at least 90 mol%. The upper limit of the content of the compound giving the structural unit (A-1) or the compound giving the structural unit (A-2) is not limited, that is, 100 mol%. The tetracarboxylic acid component may consist only of the compound giving the structural unit (A-1) or the compound giving the structural unit (A-2), and preferably consists only of the compound giving the structural unit (A-1). .

The tetracarboxylic acid component may contain a compound that provides the above structural unit (A-3) within a range that does not impair the physical properties of low retardation.
Examples of the compound providing the structural unit (A-3) include a compound represented by the formula (a-3), but are not limited thereto, and may be a derivative thereof as long as the same structural unit is provided. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-3) and an alkyl ester of the tetracarboxylic acid. As the compound giving the structural unit (A-3), a compound represented by the formula (a-3) (that is, a dianhydride) is preferable.

(4) When the tetracarboxylic acid component contains a compound that provides the structural unit (A-3), it preferably contains the compound that provides the structural unit (A-3) in an amount of 55 mol% or less, more preferably 30 mol% or less. When the tetracarboxylic acid component contains a compound that gives the structural unit (A-3), it is preferably composed of only a compound that gives the structural unit (A-1) and a compound that gives the structural unit (A-3).

The tetracarboxylic acid component may include a compound other than the compound giving the structural unit (A-1), the compound giving the structural unit (A-2), and the compound giving the structural unit (A-3). Are the above-mentioned aromatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aliphatic tetracarboxylic dianhydrides, and derivatives thereof (tetracarboxylic acids, alkyl esters of tetracarboxylic acids, etc.) Is mentioned.
The compound other than the compound providing the structural units (A-1) to (A-3) arbitrarily contained in the tetracarboxylic acid component may be one type or two or more types.

Examples of the compound giving the structural unit (B-1) include a compound represented by the general formula (b1-1) and a compound represented by the general formula (b2-1), but are not limited thereto and have the same constitution. It may be a derivative thereof as long as the unit is given. Examples of the derivative include a diisocyanate corresponding to the compound represented by the general formula (b1-1) and a diisocyanate corresponding to a diamine represented by the general formula (b2-1). As the compound giving the structural unit (B-1), at least one compound selected from the group consisting of a compound represented by the general formula (b1-1) and a compound represented by the general formula (b2-1) ( That is, diamine) is preferable.

The compound providing the structural unit (B-1) preferably includes a compound represented by the general formula (b1-1), and includes a compound represented by the formula (b1-1-1) and a compound represented by the formula (b1-1). More preferably, the composition contains at least one compound selected from the group consisting of a compound represented by formula (b1-1-3) and a compound represented by formula (b1-1-3). And more preferably at least one compound selected from the group consisting of a compound represented by the formula (b1-1-2) and a compound represented by the formula (b1-1-1) Is particularly preferred.

The diamine component preferably contains 5 mol% or more, more preferably 15 mol% or more, further preferably 45 mol% or more, particularly preferably 75 mol% or more of the compound giving the structural unit (B-1). . The upper limit of the content of the compound providing the structural unit (B-1) is not particularly limited, that is, 100 mol%. The diamine component may consist only of the compound giving the structural unit (B-1).
When the compound giving the structural unit (B-1) includes the compound represented by the formula (b1-1-1), the compound represented by the formula (b1-1-1) in the compound giving the structural unit (B-1) is used. The ratio of the compound to be prepared is preferably 50 to 100 mol%, more preferably 75 to 100 mol%, further preferably 90 to 100 mol%, particularly preferably 95 to 100 mol%.

The diamine component is a compound that provides the above structural unit (B-2), a compound that provides the above structural unit (B-3), and a compound that provides the above structural unit (B) as long as the physical properties of colorless transparency and low retardation are not impaired. It may contain at least one compound selected from the group consisting of compounds giving -4).
Examples of the compound providing the structural units (B-2) to (B-4) include compounds represented by the formulas (b-2) to (b-4), but are not limited thereto, and are not limited thereto. Or a derivative thereof as long as Examples of the derivative include diisocyanates corresponding to the diamines represented by the formulas (b-2) to (b-4). As the compound giving the structural units (B-2) to (B-4), compounds represented by the formulas (b-2) to (b-4) (that is, diamines) are preferable.

When the diamine component contains a compound that provides at least one structural unit selected from the group consisting of the structural units (B-2) to (B-4), the diamine component may be any of the structural units (B-2) to (B-4). It may contain a compound giving two or more types of structural units, but preferably contains a compound giving one type of structural unit among structural units (B-2) to (B-4). That is, it is preferable that the structural unit B includes a compound that provides the structural unit (B-2), a compound that provides the structural unit (B-3), or a compound that provides the structural unit (B-4).

When the diamine component includes a compound that provides at least one structural unit selected from the group consisting of the structural units (B-2) to (B-4), the compound is contained in an amount of preferably 5 to 95 mol%, more preferably 5 to 95 mol%. The content is 7 to 85 mol%, more preferably 10 to 55 mol%, and particularly preferably 12 to 25 mol%.

The diamine component may include a compound other than the compound providing the structural units (B-1) to (B-4). Examples of the compound include the above-mentioned aromatic diamine, alicyclic diamine, and aliphatic diamine; (Such as diisocyanate).
The compound other than the compound providing the structural units (B-1) to (B-4) arbitrarily contained in the diamine component may be one kind or two or more kinds.

において In the present invention, the charge ratio of the tetracarboxylic acid component to the diamine component used in the production of the polyimide resin is preferably 0.9 to 1.1 mol of the diamine component per 1 mol of the tetracarboxylic acid component.

In the present invention, an end-capping agent may be used in the production of the polyimide resin in addition to the above-mentioned tetracarboxylic acid component and diamine component. As the terminal blocking agent, monoamines or dicarboxylic acids are preferred. The amount of the terminal blocking agent to be introduced is preferably 0.0001 to 0.1 mol, particularly preferably 0.001 to 0.06 mol, per 1 mol of the tetracarboxylic acid component. Examples of the monoamine terminal capping agent include, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, Ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline and the like are recommended. Of these, benzylamine and aniline can be suitably used. As the dicarboxylic acid terminal blocking agent, dicarboxylic acids are preferable, and a part of the dicarboxylic acids may be closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1 , 2-dicarboxylic acid and the like are recommended. Of these, 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.
As a specific reaction method, (1) a tetracarboxylic acid component, a diamine component, and a reaction solvent are charged into a reactor, and the mixture is stirred at room temperature to 80 ° C for 0.5 to 30 hours, and then heated to imidization. A method for carrying out the reaction, (2) a diamine component and a reaction solvent are charged and dissolved in a reactor, and then a tetracarboxylic acid component is charged and, if necessary, stirred at room temperature to 80 ° C. for 0.5 to 30 hours. And (3) a method in which a tetracarboxylic acid component, a diamine component, and a reaction solvent are charged into a reactor, and the temperature is immediately raised to perform an imidization reaction.

反応 The reaction solvent used in the production of the polyimide resin may be any solvent that does not inhibit the imidization reaction and can dissolve the produced polyimide. For example, aprotic solvents, phenol solvents, ether solvents, carbonate solvents and the like can be mentioned.

Specific examples of the aprotic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1,3-dimethylimidazolidinone, tetramethylurea and the like. Amide solvents, lactone solvents such as γ-butyrolactone and γ-valerolactone, phosphorus-containing amide solvents such as hexamethylphosphoric amide and hexamethylphosphine triamide, and sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide and sulfolane Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methylcyclohexanone; amine solvents such as picoline and pyridine; and ester solvents such as acetic acid (2-methoxy-1-methylethyl).

Specific examples of phenol solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4 -Xylenol, 3,5-xylenol and the like.
Specific examples of the ether solvent include 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, and bis [2- (2-methoxyethoxy) ethyl]. Ether, tetrahydrofuran, 1,4-dioxane and the like can be mentioned.
Specific examples of the carbonate-based solvent include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, propylene carbonate, and the like.
Among the above reaction solvents, amide solvents or lactone solvents are preferred. The above reaction solvents may be used alone or in combination of two or more.

In the imidization reaction, it is preferable to carry out the reaction using a Dean-Stark apparatus or the like while removing water generated during the production. By performing such an operation, the degree of polymerization and the imidization ratio can be further increased.

In the above imidation reaction, a known imidization catalyst can be used. Examples of the imidation catalyst include a base catalyst and an acid catalyst.
Base catalysts include pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N, N Organic base catalysts such as -dimethylaniline and N, N-diethylaniline; and inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogen carbonate and sodium hydrogen carbonate.
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, paratoluenesulfonic acid, and naphthalenesulfonic acid. Is mentioned. The above imidization catalysts may be used alone or in combination of two or more.
Among the above, from the viewpoint of handleability, it is preferable to use a base catalyst, more preferably to use an organic base catalyst, even more preferably to use one or more selected from triethylamine and triethylenediamine, to use triethylamine, Alternatively, it is particularly preferable to use a combination of triethylamine and triethylenediamine.

温度 The temperature of the imidization reaction is preferably from 120 to 250 ° C, more preferably from 160 to 200 ° C, from the viewpoint of the reaction rate and suppression of gelation and the like. The reaction time is preferably 0.5 to 10 hours after the start of the distillation of the produced water.

[Polyimide varnish]
The polyimide varnish of the present invention is obtained by dissolving the polyimide resin of the present invention in an organic solvent. That is, the polyimide varnish of the present invention contains the polyimide resin of the present invention and an organic solvent, and the polyimide resin is dissolved in the organic solvent.
The organic solvent is not particularly limited as long as it can dissolve the polyimide resin, but it is preferable to use the above-mentioned compounds alone or as a mixture of two or more as the reaction solvent used in the production of the polyimide resin.
The polyimide varnish of the present invention may be a polyimide solution itself in which a polyimide resin obtained by a polymerization method is dissolved in a reaction solvent, or may be a solution obtained by further adding a diluting solvent to the polyimide solution.
The polyimide varnish of the present invention may be one obtained by dissolving the polyimide resin of the present invention in a low-boiling solvent having a boiling point of 130 ° C or lower. By using the low-boiling solvent as the organic solvent, the heating temperature at the time of producing a polyimide film described later can be reduced. Examples of the low boiling point solvent include carbon tetrachloride, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydrofuran, acetone and the like, and among them, dichloromethane is preferable.

Since the polyimide resin of the present invention has solvent solubility, a varnish with a high concentration that is stable at room temperature can be obtained. The polyimide varnish of the present invention preferably contains 5 to 40% by mass of the polyimide resin of the present invention, more preferably 10 to 30% by mass. The viscosity of the polyimide varnish is preferably from 1 to 200 Pa · s, more preferably from 5 to 150 Pa · s. The viscosity of the polyimide varnish is a value measured at 25 ° C. using an E-type viscometer.
In addition, the polyimide varnish of the present invention is an inorganic filler, an adhesion promoter, a release agent, a flame retardant, a UV stabilizer, a surfactant, a leveling agent, a defoaming agent, and a fluorescent enhancer as long as the required properties of the polyimide film are not impaired. Various additives such as a whitening agent, a crosslinking agent, a polymerization initiator, and a photosensitive agent may be included.
The method for producing the polyimide varnish of the present invention is not particularly limited, and a known method can be applied.

[Polyimide film]
The polyimide film of the present invention contains the polyimide resin of the present invention. Therefore, the polyimide film of the present invention is excellent in colorless transparency and further has low retardation. Suitable physical properties of the polyimide film of the present invention are as described above.
The method for producing the polyimide film of the present invention is not particularly limited, and a known method can be used. For example, the polyimide varnish of the present invention, a glass plate, a metal plate, coated on a smooth support such as plastic, or after forming into a film shape, the organic solvent such as a reaction solvent or a diluting solvent contained in the varnish. A method of removing by heating and the like can be given. A release agent may be previously applied to the surface of the support, if necessary.
As a method for removing the organic solvent contained in the varnish by heating, the following method is preferable. That is, after evaporating the organic solvent at a temperature of 120 ° C. or less to form a self-supporting film, the self-supporting film is peeled off from the support, the end of the self-supporting film is fixed, and the organic solvent used It is preferable to produce a polyimide film by drying at a temperature equal to or higher than the boiling point. Further, it is preferable to dry under a nitrogen atmosphere. The pressure of the drying atmosphere may be any of reduced pressure, normal pressure, and pressure. The heating temperature for producing the polyimide film by drying the self-supporting film is not particularly limited, but is preferably from 200 to 400 ° C.
When the organic solvent contained in the polyimide varnish of the present invention is a low-boiling solvent having a boiling point of 130 ° C. or lower, the heating temperature of the self-supporting film is preferably from 100 to 180 ° C. Furthermore, it is preferable to perform an annealing treatment in which the polyimide film obtained by removing the low boiling point solvent is further heated at a temperature equal to or higher than the glass transition temperature.

Further, the polyimide film of the present invention can also be produced using a polyamic acid varnish obtained by dissolving polyamic acid in an organic solvent.
The polyamic acid contained in the polyamic acid varnish is a precursor of the polyimide resin of the present invention, and includes a compound providing the above-mentioned structural unit (A-1) and a compound giving the above-mentioned structural unit (A-2). It is a product of a polyaddition reaction between a tetracarboxylic acid component containing at least one selected from the group and a diamine component containing a compound giving the above-mentioned structural unit (B-1). By imidizing (dehydrating and ring-closing) this polyamic acid, the polyimide resin of the present invention as a final product is obtained.
As the organic solvent contained in the polyamic acid varnish, the organic solvent contained in the polyimide varnish of the present invention can be used.
In the present invention, the polyamic acid varnish comprises a tetracarboxylic acid component containing at least one selected from the group consisting of a compound giving the above-mentioned structural unit (A-1) and a compound giving the above-mentioned structural unit (A-2). The polyamic acid solution itself obtained by polyaddition reaction with a diamine component containing the compound giving the above-mentioned structural unit (B-1) in a reaction solvent may be used, or may be further diluted with respect to the polyamic acid solution. A solvent may be added.

The method for producing a polyimide film using a polyamic acid varnish is not particularly limited, and a known method can be used. For example, a polyamic acid varnish is coated on a smooth support such as a glass plate, a metal plate, or a plastic, or formed into a film, and an organic solvent such as a reaction solvent or a diluting solvent contained in the varnish is removed by heating. Thus, a polyamic acid film is obtained, and the polyamic acid in the polyamic acid film is imidized by heating to produce a polyimide film.
The heating temperature for drying the polyamic acid varnish to obtain a polyamic acid film is preferably 50 to 120 ° C. The heating temperature when the polyamic acid is imidized by heating is preferably from 200 to 400 ° C.
The method of imidization is not limited to thermal imidization, and chemical imidization can be applied.

The thickness of the polyimide film of the present invention can be appropriately selected according to the application and the like, but is preferably in the range of 1 to 250 μm, more preferably 5 to 100 μm, and still more preferably 10 to 80 μm. When the thickness is 1 to 250 μm, practical use as a self-supporting film becomes possible.
The thickness of the polyimide film can be easily controlled by adjusting the solid content concentration and the viscosity of the polyimide varnish.

Hereinafter, the present invention will be described specifically with reference to examples. However, the present invention is not limited at all by these examples.
The solid content concentration of the varnishes obtained in Examples and Comparative Examples and each physical property of the films were measured by the following methods.

(1) Solid Content Concentration The solid content concentration of the varnish was measured by heating a sample at 280 ° C. for 120 minutes in a small electric furnace “MMF-1” manufactured by As One Corporation, and calculating from the mass difference between the sample before and after heating.
(2) Film thickness The film thickness was measured using a micrometer manufactured by Mitutoyo Corporation.
(3) Total light transmittance, yellow index (YI), haze The total light transmittance, YI, and haze were measured using a simultaneous color / turbidity meter “COH400” manufactured by Nippon Denshoku Industries Co., Ltd. The measurement of total light transmittance and YI was based on JIS K7361-1: 1997, and the measurement of haze was based on JIS K7136: 2000. (4) Thickness phase difference (Rth)
The thickness retardation (Rth) was measured using an ellipsometer “M-220” manufactured by JASCO Corporation. The value of thickness retardation at a measurement wavelength of 550 nm was measured. Note that Rth is represented by the following formula, when the maximum in-plane refractive index of the polyimide film is nx, the minimum is ny, the refractive index in the thickness direction is nz, and the thickness of the film is d. Things.
Rth = [{(nx + ny) / 2} −nz] × d

The tetracarboxylic acid component and the diamine component used in Examples and Comparative Examples, and their abbreviations are as follows.
<Tetracarboxylic acid component>
HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Company; compound represented by formula (a-1))
CpODA: norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride (manufactured by JXTG Energy Corporation; Compound represented by formula (a-3))
<Diamine component>
BisAM: 1,3-bis [2- (4-aminophenyl) -2-propyl] benzene (compound represented by formula (b1-1-1), manufactured by Mitsui Chemicals, Inc.)
TPER: 1,3-bis (4-aminophenoxy) benzene (compound represented by formula (b1-1-2), manufactured by Wakayama Seika Kogyo Co., Ltd.)
APBN: 1,3-bis (3-aminophenoxy) benzene (a compound represented by formula (b1-1-3) manufactured by Mitsui Chemicals, Inc.)
TPEQ: 1,4-bis (4-aminophenoxy) benzene (manufactured by Wakayama Seika Kogyo Co., Ltd.)
3,5-DABA: 3,5-diaminobenzoic acid (manufactured by Nippon Pure Chemicals Co., Ltd.)
BAPA: 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (manufactured by Wakayama Seika Kogyo Co., Ltd.)
ODA: 4,4'-diaminodiphenyl ether (compound represented by formula (b-3), manufactured by Wakayama Seika Kogyo Co., Ltd.)
BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane (compound represented by formula (b-2), manufactured by Wakayama Seika Kogyo Co., Ltd.)
3,4'-DPE: 3,4'-diaminodiphenyl ether (manufactured by Wakayama Seika Kogyo Co., Ltd.)
BisAP: 1,4-bis [2- (4-aminophenyl) -2-propyl] benzene (manufactured by Mitsui Chemicals, Inc., compound represented by formula (b-4))

The details of the solvent and catalyst used in the examples and comparative examples are as follows.
γ-butyrolactone (Mitsubishi Chemical Corporation)
N, N-dimethylacetamide (Mitsubishi Gas Chemical Co., Ltd.)
Triethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.)
Triethylamine (Kanto Chemical Co., Ltd.)

<Example 1>
A stainless steel half-moon stirring blade, a Dean-Stark apparatus equipped with a nitrogen inlet tube and a cooling tube, a thermometer, and a 0.3 L 5-neck glass round bottom flask equipped with a glass end cap were used. In the round bottom flask, 25.920 g (0.075 mol) of BisAM, 35.0 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Corporation), and 0.048 g of triethylenediamine and 3.80 g of triethylamine were used as catalysts. The solution was heated to 70 ° C. while stirring at 150 rpm in a nitrogen atmosphere to obtain a solution. To this solution, 16.830 g (0.075 mol) of HPMDA and 17.1 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature in the reaction system to 200 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 200 ° C. for 5.5 hours. After adding 67.71 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid concentration of 25% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 30 μm. Table 1 shows the evaluation results of this polyimide film.

<Example 2>
Using the same reactor as in Example 1, 24.899 g (0.085 mol) of APBN, 40.0 g of γ-butyrolactone, and 4.30 g of triethylamine as a catalyst were placed in a round bottom flask in a nitrogen atmosphere. The solution was heated to 70 ° C. while stirring at 150 rpm to obtain a solution. To this solution, 19.074 g (0.085 mol) of HPMDA and 13.7 g of γ-butyrolactone were added all at once, and then heated with a mantle heater, and the temperature in the reaction system was raised to 190 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 3.3 hours. After adding 41.6 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 30% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 47 μm. Table 1 shows the evaluation results of this polyimide film.

<Example 3>
Using the same reaction apparatus as in Example 1, 24.337 g (0.083 mol) of TPER, 45.1 g of γ-butyrolactone, and 2.11 g of triethylamine as a catalyst were placed in a round-bottom flask in a nitrogen atmosphere. The solution was heated to 70 ° C. while stirring at 150 rpm to obtain a solution. To this solution, 18.701 g (0.083 mol) of HPMDA and 19.4 g of N, N-dimethylacetamide were added all at once, and then heated with a mantle heater, and the temperature in the reaction system was reduced over about 20 minutes. The temperature was raised to 190 ° C. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 2.7 hours. After adding 64.5 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid concentration of 24% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 31 μm. Table 1 shows the evaluation results of this polyimide film.

<Comparative Example 1>
Using the same reactor as in Example 1, 23.370 g (0.080 mol) of TPEQ, 40.4 g of γ-butyrolactone, 0.41 g of triethylamine as a catalyst, and 0.41 g of nitrogen were placed in a round-bottomed flask. The solution was heated to 80 ° C. while stirring at 150 rpm to obtain a solution. To this solution, 17.934 g (0.080 mol) of HPMDA and 10.1 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature in the reaction system to 200 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 200 ° C. for 2.5 hours. After adding 103.3 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 20% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 18 μm. Table 1 shows the evaluation results of this polyimide film.

<Comparative Example 2>
Using the same reactor as in Example 1, 28.559 g (0.188 mol) of 3,5-DABA, 132.1 g of γ-butyrolactone, and 0.95 g of triethylamine as a catalyst were used in a round bottom flask. The solution was heated to 70 ° C. while stirring at 150 rpm in a nitrogen atmosphere to obtain a solution. To this solution, 42.132 g (0.188 mol) of HPMDA and 33.03 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature in the reaction system to 190 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 5.0 hours. After 90.86 g of γ-butyrolactone was added, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 20% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 29 μm. Table 1 shows the evaluation results of this polyimide film.

<Comparative Example 3>
Using the same reactor as in Example 1, 42.278 g (0.115 mol) of BAPA, 81.8 g of γ-butyrolactone, and 0.58 g of triethylamine as a catalyst were placed in a round bottom flask in a nitrogen atmosphere. The solution was heated to 70 ° C. while stirring at 150 rpm to obtain a solution. To this solution, 25.877 g (0.115 mol) of HPMDA and 20.4 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature in the reaction system to 190 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 5.0 hours. After adding 153.8 g of γ-butyrolactone, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 20% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 26 μm. Table 1 shows the evaluation results of this polyimide film.

<Comparative Example 4>
Using the same reactor as in Example 1, 20.024 g (0.100 mol) of ODA, 45.0 g of γ-butyrolactone, 1.52 g of triethylamine as a catalyst and 1.5 g of nitrogen in a round-bottomed flask, The solution was heated to 70 ° C. while stirring at 150 rpm to obtain a solution. To this solution, 22.417 g (0.100 mol) of HPMDA and 18.7 g of γ-butyrolactone were added all at once, and then heated with a mantle heater, and the temperature in the reaction system was raised to 200 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 200 ° C. for 4.0 hours. After 91.7 g of N, N-dimethylacetamide was added, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 20% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 40 μm. Table 1 shows the evaluation results of this polyimide film.

<Comparative Example 5>
Using the same reactor as in Example 1, 43.745 g (0.107 mol) of BAPP, 81.4 g of γ-butyrolactone, and 0.54 g of triethylamine as a catalyst were placed in a round-bottomed flask, and a nitrogen atmosphere was added. The solution was heated to 70 ° C. while stirring at 150 rpm to obtain a solution. To this solution, 23.887 g (0.107 mol) of HPMDA and 20.3 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Corporation) were added all at once, and the mixture was heated with a mantle heater and reacted for about 20 minutes. The temperature in the system was increased to 190 ° C. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 4.0 hours. After adding 154.2 g of γ-butyrolactone (manufactured by Mitsubishi Chemical Corporation), the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 20% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame, and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 33 μm. Table 1 shows the evaluation results of this polyimide film.

<Comparative Example 6>
Using the same reactor as in Example 1, 20.024 g (0.100 mol) of 3,4′-DPE, 45.0 g of γ-butyrolactone, and 0 0.065 g and 1.52 g of triethylamine were added, and the mixture was heated to 70 ° C. while stirring at 150 rpm under a nitrogen atmosphere to obtain a solution. To this solution, 22.417 g (0.100 mol) of HPMDA and 18.7 g of γ-butyrolactone were added all at once, and then heated with a mantle heater, and the temperature in the reaction system was raised to 200 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 200 ° C. for 4.0 hours. After 91.7 g of N, N-dimethylacetamide was added, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 20% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 25 μm. Table 1 shows the evaluation results of this polyimide film.

<Example 4>
Using the same reactor as in Example 1, 14.417 g (0.072 mol) of ODA, 6.201 g (0.018 mol) of BisAM, 40.0 g of γ-butyrolactone and As a catalyst, 0.050 g of triethylenediamine and 4.55 g of triethylamine were added, and the mixture was heated to 70 ° C. while stirring at 150 rpm in a nitrogen atmosphere to obtain a solution. To this solution, 20.175 g (0.090 mol) of HPMDA and 10.0 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature in the reaction system to 200 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 200 ° C. for 0.7 hours. After adding 38.0 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 30% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 42 μm. Table 1 shows the evaluation results of this polyimide film.

<Example 5>
Using the same reactor as in Example 1, in a round bottom flask, 10.012 g (0.050 mol) of ODA, 17.225 g (0.050 mol) of BisAM, 48.7 g of γ-butyrolactone, and As a catalyst, 0.056 g of triethylenediamine and 5.06 g of triethylamine were added, and the mixture was heated to 70 ° C. while stirring at 150 rpm in a nitrogen atmosphere to obtain a solution. To this solution, 22.417 g (0.10 mol) of HPMDA and 12.2 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature of the reaction system to 200 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 200 ° C. for 0.6 hours. After adding 77.8 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid concentration of 25% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a 34 μm thick film. Table 1 shows the evaluation results of this polyimide film.

<Example 6>
As a reaction apparatus, the same 3.0 L apparatus as in Example 1 was used, and in a round bottom flask, 23.228 g (0.116 mol) of ODA, 159.848 g (0.464 mol) of BisAM, and γ 307.0 g of butyrolactone, 0.325 g of triethylenediamine as a catalyst, and 29.345 g of triethylamine were added, and the mixture was heated to 70 ° C. while stirring at 150 rpm under a nitrogen atmosphere to obtain a solution. To this solution, 130.19 g (0.580 mol) of HPMDA and 76.8 g of γ-butyrolactone were added all at once, and then heated with a mantle heater, and the temperature in the reaction system was raised to 200 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 200 ° C. for 2.0 hours. After adding 300.0 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 30% by mass.

Subsequently, the obtained polyimide varnish is applied on a PET substrate, and the temperature is gradually increased, and is maintained at a maximum temperature of 140 ° C. for about 2 minutes. A primary dried film was obtained. Further, the film was fixed to a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 32 μm. Table 1 shows the evaluation results of this polyimide film.

<Example 7>
Using the same reactor as in Example 1, 27.259 g (0.066 mol) of BAPP, 5.719 g (0.017 mol) of BisAM, 50.6 g of γ-butyrolactone and As a catalyst, 0.047 g of triethylenediamine and 4.20 g of triethylamine were added, and the mixture was heated to 70 ° C. while stirring at 150 rpm in a nitrogen atmosphere to obtain a solution. To this solution, 18.606 g (0.083 mol) of HPMDA and 12.6 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature in the reaction system to 200 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 200 ° C. for 0.5 hour. After adding 83.0 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid concentration of 25% by mass.

<Example 8>
Using the same reactor as in Example 1, 16.421 g (0.040 mol) of BAPP, 13.780 g (0.040 mol) of BisAM, 40.0 g of γ-butyrolactone and catalyst in a round bottom flask 0.044 g of triethylenediamine and 4.05 g of triethylamine were added, and the mixture was heated to 70 ° C. while stirring at 150 rpm in a nitrogen atmosphere to obtain a solution. To this solution, 17.934 g (0.080 mol) of HPMDA and 18.8 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature of the reaction system to 190 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 2.2 hours. After adding 122.2 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid concentration of 20% by mass.

<Example 9>
Using the same reactor as in Example 1, 6.568 g (0.016 mol) of BAPP, 22.048 g (0.064 mol) of BisAM, 30.0 g of γ-butyrolactone, and As a catalyst, 0.044 g of triethylenediamine and 4.05 g of triethylamine were added, and the mixture was heated to 70 ° C. while stirring at 150 rpm in a nitrogen atmosphere to obtain a solution. To this solution, 17.934 g (0.080 mol) of HPMDA and 16.6 g of γ-butyrolactone were added all at once, and then heated with a mantle heater, and the temperature in the reaction system was raised to 190 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 1.4 hours. After adding 84.4 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 25% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame, and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 35 μm. Table 1 shows the evaluation results of this polyimide film.

<Example 10>
Using the same reactor as in Example 1, 27.560 g (0.080 mol) of BisAM, 30.8 g of γ-butyrolactone, 0.022 g of triethylenediamine, and 2% of triethylamine were used as catalysts in a round bottom flask. 0.02 g was added, and the temperature was raised to 70 ° C. while stirring at 150 rpm under a nitrogen atmosphere to obtain a solution. To this solution, 8.967 g (0.040 mol) of HPMDA, 15.375 g (0.040 mol) of CpODA, and 32.9 g of γ-butyrolactone were added all at once, and then heated with a mantle heater. The temperature in the reaction system was raised to 190 ° C. over 20 minutes. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 2.0 hours. After adding 88.0 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid concentration of 25% by mass.

Subsequently, the obtained polyimide varnish was applied on a PET substrate, kept at 100 ° C. for 20 minutes, and volatilized the solvent to obtain a self-supporting colorless and transparent primary dried film. Further, the film was fixed on a stainless steel frame and dried at 210 ° C. in an air atmosphere for 20 minutes to remove the solvent, thereby obtaining a film having a thickness of 38 μm. Table 1 shows the evaluation results of this polyimide film.

<Example 11>
Using the same reactor as in Example 1, 13.780 g (0.040 mol) of BisAP, 13.780 g (0.040 mol) of BisAM, 40.0 g of γ-butyrolactone, and As a catalyst, 0.044 g of triethylenediamine and 4.05 g of triethylamine were added, and the mixture was heated to 70 ° C. while stirring at 150 rpm in a nitrogen atmosphere to obtain a solution. To this solution, 17.934 g (0.080 mol) of HPMDA and 15.6 g of γ-butyrolactone were added all at once, and then heated with a mantle heater to raise the temperature in the reaction system to 190 ° C. in about 20 minutes. Raised. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. for 3.5 hours. After adding 114.8 g of N, N-dimethylacetamide, the mixture was stirred at about 100 ° C. for about 1 hour to obtain a uniform polyimide varnish having a solid content of 20% by mass.

As shown in Table 1, the polyimide films of Examples 1 to 11 manufactured using the specific tetracarboxylic acid component and the specific diamine component were excellent in colorless transparency and further low retardation.
On the other hand, the polyimide films of Comparative Examples 1 to 6 in which no diamine providing the structural unit (B-1) was used as the diamine component had larger retardation values (Rth) than the polyimide films of Examples 1 to 3.
The polyimide films of Examples 4 to 6 in which BisAM and ODA were used in combination as the diamine acid components had a significantly reduced retardation value (Rth) as compared with the polyimide film of Comparative Example 4 manufactured using only ODA.
The polyimide films of Examples 7 to 9 in which BisAM and BAPP were used in combination as the diamine acid component had a significantly reduced retardation value (Rth) as compared with the polyimide film of Comparative Example 5 manufactured using only BAPP.

The polyimide film of the present invention is suitably used as a film for various members such as a color filter, a flexible display, a semiconductor component, and an optical member. The polyimide film of the present invention is particularly suitably used as a substrate for an image display device such as a liquid crystal display or an OLED display.

Claims

A polyimide resin having a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine,
The structural unit A is a structural unit (A-1) derived from a compound represented by the following formula (a-1) and a structural unit (A-2) derived from a compound represented by the following formula (a-2) ) Comprising at least one structural unit selected from the group consisting of
The structural unit B is at least selected from the group consisting of a structural unit derived from a compound represented by the following general formula (b1-1) and a structural unit derived from a compound represented by the following general formula (b2-1). A polyimide resin containing one structural unit (B-1).

(Wherein X 1 to X 4 are each independently a single bond, an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 2 to 5 carbon atoms, —S—, —SO—, —SO 2 —, —O -Or -CO-.)
The polyimide resin according to claim 1, wherein the ratio of the structural unit (B-1) in the structural unit B is 5 to 100 mol%.
3. The polyimide resin according to claim 1, wherein the structural unit A contains the structural unit (A-1), and the ratio of the structural unit (A-1) in the structural unit A is 45 to 100 mol%.
Wherein the structural unit (B-1) is a structural unit derived from a compound represented by the following formula (b1-1-1), a structural unit derived from a compound represented by the following formula (b1-1-2), and 4. The polyimide resin according to claim 1, comprising at least one structural unit selected from the group consisting of structural units derived from a compound represented by the following formula (b1-1-3).
The structural unit B further includes 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) 5. The method according to claim 1, which comprises at least one structural unit selected from the group consisting of a structural unit (B-4) derived from a compound represented by the following formula (b-4). Polyimide resin.
6. The polyimide according to claim 5, wherein the ratio of the total of the structural units (B-2), (B-3) and (B-4) in the structural unit B is 5 to 95 mol%. resin.
7. The polyimide resin according to claim 1, wherein the structural unit A further includes a structural unit (A-3) derived from a compound represented by the following formula (a-3).
(8) A polyimide varnish obtained by dissolving the polyimide resin according to any one of (1) to (7) in an organic solvent.
(8) A polyimide film comprising the polyimide resin according to any one of (1) to (7).