WO2019216151A1

WO2019216151A1 - Polyamide-imide resin, polyamide-imide varnish, and polyamide-imide film

Info

Publication number: WO2019216151A1
Application number: PCT/JP2019/016583
Authority: WO
Inventors: 洋平安孫子; 慎司関口; 末永　修也
Original assignee: 三菱瓦斯化学株式会社
Priority date: 2018-05-10
Filing date: 2019-04-18
Publication date: 2019-11-14
Also published as: CN111989353B; TWI787499B; KR20210007960A; CN111989353A; TW201946954A; JP7375749B2; JPWO2019216151A1

Abstract

The present invention provides: a polyamide–imide resin that can be used to form a film having excellent mechanical characteristics, heat resistance, and transparency, and also having reduced residual stress; and a polyamide-imide varnish and polyamide-imide film containing the polyamide-imide resin. The present invention pertains to: a polyamide-imide resin having constituent unit A derived from a tetracarboxylic dianhydride, constituent unit B derived from a diamine, and constituent unit C derived from an aromatic dicarboxylic acid dichloride, wherein constituent unit A contains a constituent unit (A-1) derived from a compound represented by formula (a-1), constituent unit B contains a constituent unit (B-1) derived from a compound represented by formula (b-1), and constituent unit C contains a constituent unit (C-1) derived from a compound represented by formula (c-1); and a polyamide-imide varnish and polyamide-imide film containing the polyamide-imide resin.

Description

Polyamide-imide resin, polyamide-imide varnish and polyamide-imide film

The present invention relates to a polyamide-imide resin, a polyamide-imide varnish, and a polyamide-imide film.

Generally, polyimide resins have excellent mechanical properties and heat resistance, and thus are being used in various fields such as electrical 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 or flexibility of the device. Research is ongoing. High transparency is required for polyimide films for such applications.

When a varnish applied on a glass support or a silicon wafer is heated to form a polyimide film, residual stress is generated in the polyimide film. When the residual stress of the polyimide film is large, there arises a problem that the glass support or the silicon wafer is warped. Therefore, the polyimide film is also required to reduce the residual stress.
On the other hand, attempts have been made to mix or copolymerize polyamide with polyimide resin which is the main material of polyimide film.
Patent Document 1 discloses a unit structure derived from 2,2′-bis (trifluoromethyl) benzidine as a copolymerized polyamide-imide film having excellent thermal, mechanical and optical properties, 4,4 ′-(hexa Unit structure derived from fluoroisopropylidene) diphthalic anhydride, unit structure derived from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and unit structure derived from terephthalic acid chloride (TPC) A resin is disclosed.
Patent Document 2 discloses a fragrance containing at least one selected from 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride, cyclobutanetetracarboxylic dianhydride, and cyclopentanetetracarboxylic dianhydride. Polyamide-imide resin, which is an imidized polyamic acid obtained by copolymerization of an aromatic dianhydride, an aromatic dicarbonyl compound, and an aromatic diamine containing 2,2′-bis (trifluoromethyl) benzidine Has been.

Special table 2014-528490 gazette Special table 2017-503887 gazette

As described above, the polyimide film is required to have high transparency and low residual stress, but it is not easy to improve these characteristics while maintaining excellent mechanical characteristics and heat resistance.
This invention is made | formed in view of such a condition, The subject of this invention is excellent in a mechanical characteristic, heat resistance, and transparency, and also the formation of the film in which reduction of a residual stress is achieved is possible. The object is to provide a polyamide-imide resin, and a polyamide-imide varnish and a polyamide-imide film containing the polyamide-imide resin.

The present inventors have found that a polyamide-imide resin containing a specific combination of structural units can solve the above problems, and have completed the invention.

That is, the present invention relates to the following [1] to [8].
[1]
A polyamide-imide resin having a structural unit A derived from tetracarboxylic dianhydride, a structural unit B derived from diamine, and a structural unit C derived from aromatic dicarboxylic acid chloride,
The structural unit A includes a structural unit (A-1) derived from a compound represented by the following formula (a-1),
The structural unit B includes a structural unit (B-1) derived from a compound represented by the following formula (b-1),
A polyamide-imide resin in which the structural unit C includes a structural unit (C-1) derived from a compound represented by the following formula (c-1).

[2]
The ratio of the structural unit (A-1) in the total of the structural unit A and the structural unit C is 10 to 90 mol%,
The polyamide-imide resin according to the above [1], wherein the ratio of the structural unit (C-1) in the total of the structural unit A and the structural unit C is 10 to 60 mol%.
[3]
The polyamide-imide resin according to claim 1 or 2, wherein the structural unit A includes a structural unit (A-2) derived from a compound represented by the following formula (a-2).

[4]
The polyamide-imide resin according to the above [3], wherein the proportion of the structural unit (A-2) in the total of the structural unit A and the structural unit C is 50 mol% or less.
[5]
The polyamide-imide resin according to any one of [1] to [4] above, wherein the proportion of the structural unit (C-1) in the structural unit C is 50 mol% or more.
[6]
The polyamide-imide resin according to any one of [1] to [5] above, wherein the proportion of the structural unit (B-1) in the structural unit B is 50 mol% or more.
[7]
A polyamide-imide varnish obtained by dissolving the polyamide-imide resin according to any one of [1] to [6] above in an organic solvent.
[8]
A polyamide-imide film comprising the polyamide-imide resin according to any one of [1] to [6] above.

According to the present invention, it is possible to form a film that is excellent in mechanical properties, heat resistance, and transparency, and further achieves a reduction in residual stress.

[Polyamide-imide resin]
The polyamide-imide resin of the present invention has a structural unit A derived from tetracarboxylic dianhydride, a structural unit B derived from diamine, and a structural unit C derived from aromatic dicarboxylic acid chloride.
The structural unit A includes a structural unit (A-1) derived from a compound represented by the following formula (a-1),
The structural unit B includes a structural unit (B-1) derived from a compound represented by the following formula (b-1),
The structural unit C includes a structural unit (C-1) derived from a compound represented by the following formula (c-1).

The polyamide-imide resin of the present invention has a structure in which the structural unit A and the structural unit B are connected by an imide bond in the molecular chain, and a structure in which the structural unit C and the structural unit B are connected by an amide bond. Is included.

<Structural unit A>
The structural unit A is a structural unit derived from tetracarboxylic dianhydride in the polyamide-imide resin, and includes a structural unit (A-1) derived from a compound represented by the following formula (a-1). . The structural unit A may contain a structural unit (A-2) derived from a compound represented by the following formula (a-2) in addition to the structural unit (A-1).

The compound represented by the formula (a-1) is norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic Acid dianhydride.

The compound represented by the formula (a-2) is biphenyltetracarboxylic dianhydride (BPDA), and specific examples thereof include 3,3 ′, 4, represented by the following formula (a-2s): 4′-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) represented by the following formula (a-2a), Examples thereof include 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride (i-BPDA) represented by the following formula (a-2i).

When the structural unit A includes at least the structural unit (A-1), the mechanical properties, heat resistance and transparency of the film are further improved, and the residual stress is further decreased. Further, when the structural unit A contains the structural unit (A-2) in addition to the structural unit (A-1), the mechanical properties of the film are further improved, and the residual stress is further reduced.

The ratio of the structural unit (A-1) in the structural unit A is preferably 30 mol% or more, more preferably 40 mol% or more, and further preferably 50 mol% or more. The upper limit value of the ratio of the structural unit (A-1) is not particularly limited, that is, 100 mol%. The structural unit A may consist of only the structural unit (A-1).

The ratio of the structural unit (A-2) in the structural unit A is preferably 70 mol% or less, more preferably 15 to 60 mol%, and still more preferably 25 to 50 mol%.
The total ratio of the structural units (A-1) and (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. And particularly preferably 99 mol% or more. The upper limit value of the total ratio of the structural units (A-1) and (A-2) is not particularly limited, that is, 100 mol%. The structural unit A may consist of only the structural unit (A-1) and the structural unit (A-2).

The ratio of the structural unit (A-1) in the total of the structural unit A and the structural unit C is preferably 10 to 90 mol%, more preferably 30 to 85 mol%, still more preferably 35 to 75 mol%. %.
The ratio of the structural unit (A-2) in the total of the structural unit A and the structural unit C is preferably 50 mol% or less, more preferably 5 to 45 mol%, still more preferably 10 to 35 mol%. It is.
The ratio of the total of the structural units (A-1) and (A-2) in the total of the structural unit A and the structural unit C is preferably 40 to 90 mol%, more preferably 50 to 85 mol%. More preferably, it is 60 to 75 mol%.

The structural unit A may include structural units other than the structural units (A-1) and (A-2). The tetracarboxylic dianhydride that gives such a structural unit is not particularly limited, but pyromellitic dianhydride, 9,9′-bis (3,4-dicarboxyphenyl) fluorene dianhydride, and 4 , 4 ′-(Hexafluoroisopropylidene) diphthalic anhydride and other aromatic tetracarboxylic dianhydrides (excluding compounds represented by formula (a-2)); 1,2,3,4- Cyclobutanetetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydrides such as 1,2,4,5-cyclohexanetetracarboxylic dianhydride (provided that the compound represented by the formula (a-1) And aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride.
In this specification, an aromatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing one or more aromatic rings, and an alicyclic tetracarboxylic dianhydride means one alicyclic ring. The tetracarboxylic dianhydride containing the above and containing no aromatic ring means an aliphatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing neither an aromatic ring nor an alicyclic ring.
The structural units other than the structural units (A-1) and (A-2) optionally contained in the structural unit A may be one type or two or more types.

<Structural unit B>
The structural unit B is a structural unit derived from a diamine in the polyamide-imide resin, and includes a structural unit (B-1) derived from a compound represented by the following formula (b-1).

The compound represented by the formula (b-1) is 2,2′-bis (trifluoromethyl) benzidine.
When the structural unit B includes the structural unit (B-1), the transparency and heat resistance of the film are improved, and the residual stress is reduced.

The ratio of the structural unit (B-1) in the structural unit B is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol%. % Or more. The upper limit value of the ratio of the structural unit (B-1) is not particularly limited, that is, 100 mol%. The structural unit B may consist of only the structural unit (B-1).

The structural unit B may include a structural unit other than the structural unit (B-1). The diamine which gives such a structural unit is not particularly limited, but 1,4-phenylenediamine, p-xylylenediamine, 3,5-diaminobenzoic acid, 1,5-diaminonaphthalene, 2,2′-dimethyl Biphenyl-4,4′-diamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4′-diaminodiphenylsulfone, 4 , 4′-diaminobenzanilide, 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-indene-5-amine, α, α′-bis (4-aminophenyl) ) -1,4-diisopropylbenzene, N, N′-bis (4-aminophenyl) terephthalamide, 4,4′-bis (4-aminophenoxy) Biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2,2′-bis (trifluoromethyl) ) -4,4′-diaminodiphenyl ether, and aromatic diamines such as 9,9-bis (4-aminophenyl) fluorene (excluding the compound represented by the formula (b-1)); And alicyclic diamines such as bis (aminomethyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.
In this specification, an aromatic diamine means a diamine containing one or more aromatic rings, an alicyclic diamine means a diamine containing one or more alicyclic rings and no aromatic ring, A group diamine means a diamine containing neither an aromatic ring nor an alicyclic ring.
The number of structural units other than the structural unit (B-1) optionally included in the structural unit B may be one or more.

<Structural unit C>
The structural unit C is a structural unit derived from an aromatic dicarboxylic acid chloride in the polyamide-imide resin, and includes a structural unit (C-1) derived from a compound represented by the following formula (c-1).

The compound represented by the formula (c-1) is terephthalic acid chloride.
When the structural unit C includes the structural unit (C-1), the mechanical properties, heat resistance and transparency of the film are improved, and the residual stress is reduced.

The ratio of the structural unit (C-1) in the structural unit C is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol%. % Or more. The upper limit value of the ratio of the structural unit (C-1) is not particularly limited, that is, 100 mol%. The structural unit C may consist of only the structural unit (C-1).
The ratio of the structural unit (C-1) in the total of the structural unit A and the structural unit C is preferably 10 to 60 mol%, more preferably 15 to 50 mol%, and still more preferably 25 to 40 mol%. %.

The structural unit C may include a structural unit other than the structural unit (C-1). The aromatic dicarboxylic acid chloride giving such a structural unit is not particularly limited, and examples thereof include 4,4′-biphenyldicarbonyl chloride, 4,4′-oxydibenzoyl chloride, and isophthalic acid chloride.
The number of structural units other than the structural unit (C-1) optionally contained in the structural unit C may be one or two or more.

The number average molecular weight of the polyamide-imide resin of the present invention is preferably 5,000 to 300,000, more preferably 5,000 to 100,000, from the viewpoint of mechanical strength of the obtained polyamide-imide film. The number average molecular weight of the polyamide-imide resin can be determined from, for example, a standard polymethyl methacrylate (PMMA) conversion value measured by gel filtration chromatography.

The polyamide-imide resin of the present invention comprises a polyimide chain (structure in which structural unit A and structural unit B are imide-bonded) and a polyamide chain (structure in which structural unit C and structural unit B are amide-bonded). The structure etc. which contain are mentioned.
In the polyamide-imide resin of the present invention, the molar ratio of the structural unit A to the structural unit C (structural unit A / structural unit C) is preferably 40/60 to 90/10, more preferably 50/50 to 85 /. 15 and more preferably 60/40 to 75/25.

The polyamide-imide resin of the present invention has a polyimide chain (structure in which the structural unit A and the structural unit B are imide-bonded) and a polyamide chain (structure in which the structural unit C and the structural unit B are amide-bonded). It is preferable to include as a main structure. Therefore, the total ratio of the polyimide chain and the polyamide chain in the polyamide-imide resin of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, and further preferably 50% by mass or more. Especially preferably, it is 60 mass% or more.

By using the polyamide-imide resin of the present invention, it is possible to form a film that is excellent in mechanical properties, heat resistance, and transparency, and further achieves a reduction in residual stress. Is as follows.

The tensile elastic modulus is preferably 2.5 GPa or more, more preferably 3.0 GPa or more, and further preferably 4.0 GPa or more.
The tensile strength is preferably 100 MPa or more, more preferably 120 MPa or more, and further preferably 150 MPa or more.
The glass transition temperature (Tg) is preferably 320 ° C. or higher, more preferably 350 ° C. or higher, and still more preferably 365 ° C. or higher.
The total light transmittance is preferably 88% or more, more preferably 88.5% or more, and further preferably 89% or more, when a film having a thickness of 10 μm is formed.
The residual stress is preferably 18.0 MPa or less, more preferably 15.0 MPa or less, and even more preferably 10.0 MPa or less.
In addition, the said physical-property value in this invention can be specifically measured by the method as described in an Example.

[Production method of polyamide-imide resin]
In the polyamide-imide resin of the present invention, the tetracarboxylic acid component containing the compound giving the structural unit (A-1) was reacted with the diamine component containing the compound giving the structural unit (B-1). Thereafter, it can be produced by reacting a dicarboxylic acid component containing a compound that gives the structural unit (C-1).

Examples of the compound that provides the structural unit (A-1) include compounds represented by the formula (a-1), but are not limited thereto, and may be derivatives thereof within a range that provides the same structural unit. Examples of the derivative include tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-1) (that is, norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″). -Norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid), and alkyl esters of the tetracarboxylic acid. As the compound giving the structural unit (A-1), a compound represented by the formula (a-1) (that is, dianhydride) is preferable.

The tetracarboxylic acid component may contain a compound that provides the structural unit (A-2).
Examples of the compound that provides the structural unit (A-2) include compounds represented by the formula (a-2), but are not limited thereto, and may be derivatives thereof within a range that provides the same structural unit. 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, dianhydride) is preferable.

The tetracarboxylic acid component preferably contains 30 mol% or more, more preferably 40 mol% or more, and still more preferably 50 mol% or more of the compound that gives the structural unit (A-1). The upper limit of the content of the compound giving the structural unit (A-1) is not particularly limited, that is, 100 mol%. The tetracarboxylic acid component may consist only of a compound that provides the structural unit (A-1).

When the tetracarboxylic acid component contains the structural unit (A-2), the tetracarboxylic acid component preferably contains 70 mol% or less of the compound that gives the structural unit (A-2), more preferably 15 to 60%. Containing mol%, more preferably 25 to 50 mol%.
The tetracarboxylic acid component contains, in total, a compound that provides the structural unit (A-1) and a compound that provides the structural unit (A-2), preferably 50 mol% or more, more preferably 70 mol% or more, and still more preferably Contains 90 mol% or more, particularly preferably 99 mol% or more. The upper limit of the total content of the compound that provides the structural unit (A-1) and the compound that provides the structural unit (A-2) is not particularly limited, that is, 100 mol%. The tetracarboxylic acid component may consist only of a compound that provides the structural unit (A-1) and a compound that provides the structural unit (A-2).

The tetracarboxylic acid component may include a compound other than the compound that provides the structural unit (A-1) and the compound that provides the structural unit (A-2). Examples of the compound include the aromatic tetracarboxylic dianhydride described above. , Alicyclic tetracarboxylic dianhydrides, and aliphatic tetracarboxylic dianhydrides, and derivatives thereof (tetracarboxylic acids, alkyl esters of tetracarboxylic acids, etc.).
The compound other than the compound giving the structural unit (A-1) and the compound giving the structural unit (A-2) optionally contained in the tetracarboxylic acid component may be one kind or two or more kinds.

Examples of the compound that provides the structural unit (B-1) include compounds represented by the formula (b-1), but are not limited thereto, and may be derivatives thereof within a range that provides the same structural unit. Examples of the derivative include diisocyanates corresponding to the diamine represented by the formula (b-1). As the compound that gives the structural unit (B-1), a compound represented by the formula (b-1) (that is, a diamine) is preferable.

The diamine component preferably contains 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, particularly preferably 99 mol% or more of the compound that gives the structural unit (B-1). . The upper limit of the content of the compound that gives the structural unit (B-1) is not particularly limited, that is, 100 mol%. The diamine component may consist only of a compound that provides the structural unit (B-1).

The diamine component may contain a compound other than the compound that gives the structural unit (B-1). Examples of the compound include the above-mentioned aromatic diamine, alicyclic diamine, and aliphatic diamine, and derivatives thereof (such as diisocyanate). Is mentioned.
The compound other than the compound that provides the structural unit (B-1) optionally contained in the diamine component may be one kind or two or more kinds.

Examples of the compound that provides the structural unit (C-1) include compounds represented by the formula (c-1), but are not limited thereto and may be derivatives thereof within a range that provides the same structural unit. Examples of the derivative include other dicarboxylic acid halides corresponding to the dicarboxylic acid chloride represented by the formula (c-1) (that is, acid fluoride, acid bromide, acid iodide). As the compound giving the structural unit (C-1), a compound represented by the formula (c-1) (that is, an acid chloride) is preferable.

The dicarboxylic acid component preferably contains 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, particularly preferably 99 mol% or more of the compound that gives the structural unit (C-1). Including. The upper limit of the content of the compound giving the structural unit (C-1) is not particularly limited, that is, 100 mol%. The dicarboxylic acid component may consist only of the compound giving the structural unit (C-1).

The dicarboxylic acid component may contain a compound other than the compound giving the structural unit (C-1), and examples of the compound include the above-mentioned aromatic dicarboxylic acid chlorides and other carboxylic acid halides corresponding thereto (that is, acid fluorides). Compound, acid bromide, acid iodide).
The number of compounds other than the compound that gives the structural unit (C-1) optionally contained in the dicarboxylic acid component may be one, or two or more.

In the present invention, the charge ratio [(tetracarboxylic acid component + dicarboxylic acid component) / diamine component, molar ratio] of the total of the tetracarboxylic acid component and dicarboxylic acid component used in the production of the polyamide-imide resin and the diamine component is: The diamine component is preferably 0.9 to 1.1 mol with respect to 1 mol in total of the tetracarboxylic acid component and the dicarboxylic acid component.

In the present invention, the charge ratio of the tetracarboxylic acid component and the dicarboxylic acid component used in the production of the polyamide-imide resin (tetracarboxylic acid component / dicarboxylic acid component, molar ratio) is preferably 40/60 to 90/10, 50/50 to 85/15 is more preferable, and 60/40 to 75/25 is still more preferable.

In the present invention, a terminal-blocking agent may be used in the production of the polyamide-imide resin in addition to the above-described tetracarboxylic acid component dicarboxylic acid component and diamine component. As end-capping agents, monoamines or dicarboxylic acids are preferred.
The amount of the terminal blocking agent 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 monoamine end-capping agents include 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. Of these, benzylamine and aniline can be preferably used.
Examples of dicarboxylic acid end-capping agents include dicarboxylic acids (excluding the aforementioned dicarboxylic acid component), and a cyclic carboxylic acid anhydride in which two carboxy groups in the molecule have undergone a dehydration condensation reaction, and Dicarboxylic acids that can form carboxylic anhydrides are preferred. Specifically, 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. Of these, phthalic acid and phthalic anhydride can be suitably used.

There is no restriction | limiting in particular in the method of making the above-mentioned tetracarboxylic acid component, a diamine component, and a dicarboxylic acid component react, A well-known method can be used.
Specifically, (1) a tetracarboxylic acid component, a diamine component, and a reaction solvent are charged into a reactor, stirred at room temperature to 80 ° C. for 0.5 to 30 hours, and then heated to imidize. A method in which a dicarboxylic acid component is added and then agitated at room temperature to 80 ° C. for 0.5 to 30 hours to perform an amidation reaction. (2) A diamine component and a reaction solvent are charged into a reactor and dissolved. Thereafter, a tetracarboxylic acid component is charged, and if necessary, stirred at room temperature to 80 ° C. for 0.5 to 30 hours. Thereafter, the temperature is raised to carry out an imidization reaction, and then the dicarboxylic acid component is added, and the room temperature to 80 (3) A tetracarboxylic acid component, a diamine component, and a reaction solvent are charged into a reactor and stirred at room temperature to 80 ° C. for 0.5 to 30 hours. And dicarboxylic acid Add a minute, stir at room temperature to 80 ° C for 0.5 to 30 hours to perform amidation reaction, then raise the temperature to perform imidization reaction, (4) Charge diamine component and reaction solvent into the reactor Then, the tetracarboxylic acid component is charged, and if necessary, stirred at room temperature to 80 ° C. for 0.5 to 30 hours. Further, the dicarboxylic acid component is added, and if necessary, 0.5 to 30 ° C. at room temperature to 80 ° C. Stirring for 30 hours to perform amidation reaction, then raising temperature and performing imidization reaction, (5) Charge tetracarboxylic acid component, diamine component, dicarboxylic acid component, and reaction solvent into reactor, necessary Depending on the method, the amidation reaction may be carried out by stirring at room temperature to 80 ° C. for 0.5 to 30 hours, and then the temperature may be raised to carry out the imidization reaction.

The reaction solvent used for the production of the polyamide-imide resin may be any solvent that does not inhibit the amidation reaction and the imidization reaction and can dissolve the produced polyamide-imide resin. For example, an aprotic solvent, a phenol solvent, an ether solvent, a carbonate solvent, and the like can be given.

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

Specific examples of the phenol solvent 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 ether solvents include 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl]. Examples include ether, tetrahydrofuran, 1,4-dioxane and the like.
Specific examples of the carbonate 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 preferable. Moreover, you may use said reaction solvent individually or in mixture of 2 or more types.

In the amidation reaction and imidation reaction, it is preferable to perform the reaction using a Dean Stark apparatus or the like while removing water produced during production. By performing such an operation, the degree of polymerization and the imidization rate can be further increased.

In the above imidation reaction, a known imidation catalyst can be used. Examples of the imidization 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 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, etc. Is mentioned. The above imidation catalysts may be used alone or in combination of two or more.
Among these, from the viewpoint of handleability, it is preferable to use a base catalyst, more preferably an organic base catalyst, still more preferably triethylamine, and particularly preferably a combination of triethylamine and triethylenediamine.

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

[Polyamide-imide varnish]
The polyamide-imide varnish of the present invention is obtained by dissolving the polyamide-imide resin of the present invention in an organic solvent. That is, the polyamide-imide varnish of the present invention contains the polyamide-imide resin of the present invention and an organic solvent, and the polyamide-imide resin is dissolved in the organic solvent.
The organic solvent is not particularly limited as long as it dissolves the polyamide-imide resin, and the above-mentioned compounds as reaction solvents used for the production of the polyamide-imide resin may be used alone or in combination of two or more. preferable.
The polyamide-imide varnish of the present invention may be a polyamide-imide solution itself in which a polyamide-imide resin obtained by a polymerization method is dissolved in a reaction solvent, or a dilution solvent is further added to the polyamide-imide solution. It may be a thing.

Since the polyamide-imide resin of the present invention has solvent solubility, it can be a highly concentrated varnish stable at room temperature. The polyamide-imide varnish of the present invention preferably contains 5 to 40% by mass of the polyamide-imide resin of the present invention, and more preferably 10 to 30% by mass. The viscosity of the polyamide-imidoimide varnish is preferably 1 to 200 Pa · s, more preferably 5 to 150 Pa · s. The viscosity of the polyamide-imide varnish is a value measured at 25 ° C. using an E-type viscometer.
The polyamide-imide varnish of the present invention is an inorganic filler, an adhesion promoter, a release agent, a flame retardant, an ultraviolet stabilizer, a surfactant, a leveling agent, and an antifoaming agent as long as the required properties of the polyamide-imide film are not impaired. Various additives such as a fluorescent brightening agent, a crosslinking agent, a polymerization initiator, and a photosensitizer may be included.
The method for producing the polyamide-imide varnish of the present invention is not particularly limited, and a known method can be applied.

[Polyamide-imide film]
The polyamide-imide film of the present invention contains the polyamide-imide resin of the present invention. Therefore, the polyamide-imide film of the present invention is excellent in mechanical properties, heat resistance and transparency, and has a low residual stress. The preferred physical properties of the polyamide-imide film of the present invention are as described above.
There is no restriction | limiting in particular in the manufacturing method of the polyamide-imide film of this invention, A well-known method can be used. For example, the polyamide-imide varnish of the present invention is coated on a smooth support such as a glass plate, a metal plate, or a plastic, or formed into a film, and then an organic solvent such as a reaction solvent or a dilution solvent contained in the varnish. The method of removing by heating etc. is mentioned. If necessary, a release agent may be applied to the surface of the support in advance.

As the 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 ends of the self-supporting film are fixed, and the organic solvent used It is preferable to produce a polyamide-imide film by drying at a temperature equal to or higher than the boiling point. Moreover, it is preferable to dry in nitrogen atmosphere. The pressure in the dry atmosphere may be any of reduced pressure, normal pressure, and increased pressure. The heating temperature for producing the polyamide-imide film by drying the self-supporting film is not particularly limited, but is preferably 200 to 400 ° C.

The polyamide-imide film of the present invention can also be produced using a polyamide-amide acid varnish obtained by dissolving polyamide-amide acid in an organic solvent.
The polyamide-amide acid contained in the polyamide-amide acid varnish is a precursor of the polyamide-imide resin of the present invention, and includes a tetracarboxylic acid component containing a compound that gives the structural unit (A-1) described above, and A dicarboxylic acid component having an amic acid structure in which a diamine component containing a compound giving the structural unit (B-1) is bonded by a polyaddition reaction and containing a compound giving the structural unit (C-1); A product having a structure in which the diamine component containing the compound giving the structural unit (B-1) is linked by an amide bond. By imidizing (dehydrating and cyclizing) the polyamide-amide acid, the final product, the polyamide-imide resin of the present invention, is obtained.
As the organic solvent contained in the polyamide-amide acid varnish, the organic solvent contained in the polyamide-imide varnish of the present invention can be used.
In the present invention, the polyamide-amide acid varnish may be a polyamide-amide acid solution itself obtained by the reaction of the above-described tetracarboxylic acid component, diamine component, and dicarboxylic acid component, or may be based on the polyamide acid solution. Further, a dilution solvent may be added.

There is no particular limitation on the method for producing the polyamide-imide film using the polyamide-amic acid varnish, and a known method can be used. For example, a polyamide-amic acid varnish is coated on a smooth support such as a glass plate, metal plate, plastic, or formed into a film, and an organic solvent such as a reaction solvent or a dilution solvent contained in the varnish is heated. Thus, a polyamide-amide acid film is obtained by removing the polyamide-amide acid film, and the polyamide-amide acid in the polyamide-amide acid film is imidized by heating to produce a polyamide-imide film.
The heating temperature for obtaining the polyamide-amide acid film by drying the polyamide-amide acid varnish is preferably 50 to 120 ° C. The heating temperature for imidizing the polyamide-amic acid by heating is preferably 200 to 400 ° C.
The imidization method is not limited to thermal imidization, and chemical imidization can also be applied.

The thickness of the polyamide-imide film of the present invention can be appropriately selected according to the use and the like, but is preferably in the range of 1 to 100 μm, more preferably 3 to 50 μm, still more preferably 5 to 30 μm. When the thickness is 1 to 100 μm, practical use as a self-supporting film becomes possible.
The thickness of the polyamide-imide imide film can be easily controlled by adjusting the solid content concentration and viscosity of the polyamide-imide varnish.

The polyamide-imide film of the present invention is suitably used as a film for various members such as color filters, flexible displays, semiconductor parts, optical members and the like. The polyamide-imide film of the present invention is particularly preferably used as a substrate for image display devices such as liquid crystal displays and OLED displays.

Hereinafter, the present invention will be described specifically by way of examples. However, this invention is not restrict | limited at all by these Examples.
The solid content concentration of the varnish obtained in Examples and Comparative Examples and the physical properties of the film were measured by the methods shown below.

(1) Solid content concentration The solid content concentration of the varnish was calculated from the difference in mass of the sample before and after heating by heating the sample at 320 ° C. × 120 min in a small electric furnace “MMF-1” manufactured by AS ONE Corporation.
(2) Film thickness The film thickness was measured using a micrometer manufactured by Mitutoyo Corporation.
(3) Tensile Elastic Modulus and Tensile Strength The tensile elastic modulus and tensile strength were measured using a tensile tester “Strograph VG-1E” manufactured by Toyo Seiki Co., Ltd. in accordance with JIS K7127. The distance between chucks was 50 mm, the test piece size was 10 mm × 50 mm, and the test speed was 20 mm / min. The tensile modulus and the tensile strength are both excellent in mechanical properties as the numerical value is large.
(4) Glass transition temperature (Tg)
Residual stress is removed using the thermomechanical analyzer "TMA / SS6100" manufactured by Hitachi High-Tech Science Co., Ltd. under the conditions of sample size 2 mm x 20 mm, load 0.1 N, and heating rate 10 ° C / min. The temperature was raised to a sufficient temperature to remove residual stress, and then cooled to room temperature. Thereafter, the measurement of the elongation of the test piece was performed under the same conditions as the treatment for removing the residual stress, and the place where the inflection point of the elongation was observed was determined as the glass transition temperature. The larger the value of Tg, the better the heat resistance.
(5) Total Light Transmittance Total light transmittance was measured using a color / turbidity simultaneous measuring device “COH400” manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K7361-1: 1997. The closer the total light transmittance is to 100%, the better the transparency.
(6) Residual stress Using a residual stress measuring device “FLX-2320” manufactured by KLA-Tencor Corporation, the “warping amount” was measured in advance on a 4-inch silicon wafer having a thickness of 525 μm ± 25 μm. An imide varnish or a polyamide-amic acid varnish was applied using a spin coater and prebaked. Thereafter, heat treatment was performed using a hot air drier in a nitrogen atmosphere at 350 ° C. for 30 minutes, and a silicon wafer with a polyamide-imide film having a thickness of 8 to 20 μm after heating was produced. The amount of warpage of the wafer was measured using the above-described residual stress measuring apparatus, and the residual stress generated between the silicon wafer and the polyamide-imide film was evaluated.

The tetracarboxylic acid component, dicarboxylic acid component and diamine component used in Examples and Comparative Examples, and their abbreviations are as follows.
<Tetracarboxylic acid component>
CpODA: Norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride (manufactured by JX Energy Corporation; Compound represented by formula (a-1))
BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (Mitsubishi Chemical Corporation; compound represented by formula (a-2))
<Dicarboxylic acid component>
TPC: terephthalic acid chloride (Tokyo Chemical Industry Co., Ltd .; compound represented by formula (c-1))
<Diamine>
TFMB: 2,2′-bis (trifluoromethyl) benzidine (manufactured by Seika Corporation; compound represented by formula (b-1))

<Example 1>
In a 1 L 5-neck round bottom flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean Stark fitted with a cooling tube, a thermometer, and a glass end cap, 32.024 g (0.100 mol) of TFMB, N -Methyl-2-pyrrolidone (Mitsubishi Chemical Co., Ltd.) (63.570 g) was added, and the system temperature was 70 ° C. and stirred in a nitrogen atmosphere at a rotation speed of 200 rpm to obtain a solution.
To this solution, 26.907 g (0.070 mol) of CpODA and 15.894 g of N-methyl-2-pyrrolidone (Mitsubishi Chemical Corporation) were added all at once, and then triethylamine (manufactured by Kanto Chemical Co., Ltd.) as an imidization catalyst. ) 0.354 g and 0.039 g of triethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were added and heated with a mantle heater, and the reaction system temperature was raised to 190 ° C. over about 20 minutes. The components to be distilled off were collected, and the temperature in the reaction system was maintained at 190 ° C. and refluxed for 2 hours while adjusting the number of rotations according to the increase in viscosity.
Thereafter, 268.560 g of N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and the reaction system temperature was cooled to 120 ° C., followed by further stirring for about 3 hours to obtain a solid content of 15 A mass% polyimide varnish was obtained. Subsequently, 6.091 g (0.030 mol) of TPC and 204.70 g of N-methyl-2-pyrrolidone (Mitsubishi Chemical Co., Ltd.) were added, and the system was stirred for 2 hours at a system temperature of 50 ° C. and a nitrogen atmosphere at a rotation speed of 200 rpm. Thus, a polyamide-imide varnish was obtained.
Thereafter, the polyamide-imide varnish is diluted with N-methyl-2-pyrrolidone (Mitsubishi Chemical Co., Ltd.) to a solid content concentration of 5.0% by mass and added dropwise to a large excess of methanol to precipitate a polyamide-imide powder. I let you. Then, it suction-filtered with the Kiriyama funnel, and wash | cleaned twice each with a large excess methanol and ion-exchange water. A polyamide-imide powder was obtained by suction filtration with a Kiriyama funnel and drying at 200 ° C. for 2 hours in a nitrogen atmosphere.
A polyamide-imide varnish having a solid content of 10.0% by mass was obtained by dissolving 5.000 g of polyamide-imide powder in 45.000 g of N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Corporation).
Thereafter, the obtained polyamide-imide varnish is applied onto a glass or silicon wafer, held at 80 ° C. for 20 minutes on a hot plate, and then heated at 350 ° C. for 30 minutes in a hot air dryer under a nitrogen atmosphere. Evaporation gave a film with a thickness of 8 μm. The results are shown in Table 1.

<Example 2>
The same as Example 1 except that CpODA was changed from 26.907 g (0.070 mol) to 15.375 g (0.040 mol), and 8.826 g (0.030 mol) of BPDA was added simultaneously with the addition of CpODA. A polyamide-imide varnish was prepared by the method to obtain a polyamide-imide varnish having a solid content concentration of 10.0% by mass.
Using the obtained polyamide-imide varnish, a film was produced in the same manner as in Example 1 to obtain a film having a thickness of 9 μm. The results are shown in Table 1.

<Comparative Example 1>
In a 1 L 5-neck round bottom flask equipped with a stainless steel half-moon stirring blade, a nitrogen inlet tube, a Dean Stark fitted with a cooling tube, a thermometer, and a glass end cap, 32.024 g (0.100 mol) of TFMB, N -84.554 g of methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Co., Ltd.) was added, and stirred at a rotation speed of 200 rpm in a nitrogen atmosphere at a system temperature of 70 ° C to obtain a solution.
To this solution, 38.438 g (0.100 mol) of CpODA and 21.139 g of N-methyl-2-pyrrolidone (Mitsubishi Chemical Corporation) were added all at once, and then triethylamine (manufactured by Kanto Chemical Co., Ltd.) was used as an imidization catalyst. 0.506 g and 0.056 g of triethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were added and heated with a mantle heater, and the reaction system temperature was raised to 190 ° C. over about 20 minutes. The component to be distilled off was collected, and the temperature in the reaction system was maintained at 190 ° C. and refluxed for 3 hours while adjusting the number of rotations according to the increase in viscosity.
Thereafter, 4960.29 g of N-methyl-2-pyrrolidone (manufactured by Mitsubishi Chemical Co., Ltd.) was added and the reaction system internal temperature was cooled to 120 ° C., followed by further stirring for about 3 hours to obtain a solid content of 10%. A mass% polyimide varnish was obtained.
Then, the obtained polyimide varnish is applied onto a glass or silicon wafer, kept on a hot plate at 80 ° C. for 20 minutes, and then heated in a hot air dryer at 400 ° C. for 30 minutes in a nitrogen atmosphere to evaporate the solvent. And a film having a thickness of 14 μm was obtained. The results are shown in Table 1.

As shown in Table 1, it can be seen that the polyamide-imide films of Examples 1 and 2 are excellent in mechanical properties, heat resistance and transparency, and can further reduce the residual stress.
On the other hand, the polyimide film of Comparative Example 1 produced using only CpODA as the tetracarboxylic acid component without using the dicarboxylic acid component is excellent in transparency as compared with the polyamide-imide films of Examples 1 and 2. However, since the mechanical properties and heat resistance are inferior and the residual stress is high, it can be seen that the residual stress cannot be reduced.

Claims

A polyamide-imide resin having a structural unit A derived from tetracarboxylic dianhydride, a structural unit B derived from diamine, and a structural unit C derived from aromatic dicarboxylic acid chloride,
The structural unit A includes a structural unit (A-1) derived from a compound represented by the following formula (a-1),
The structural unit B includes a structural unit (B-1) derived from a compound represented by the following formula (b-1),
A polyamide-imide resin in which the structural unit C includes a structural unit (C-1) derived from a compound represented by the following formula (c-1).
The ratio of the structural unit (A-1) in the total of the structural unit A and the structural unit C is 10 to 90 mol%,
The polyamide-imide resin according to claim 1, wherein the ratio of the structural unit (C-1) in the total of the structural unit A and the structural unit C is 10 to 60 mol%.
The polyamide-imide resin according to claim 1 or 2, wherein the structural unit A includes a structural unit (A-2) derived from a compound represented by the following formula (a-2).
The polyamide-imide resin according to claim 3, wherein the proportion of the structural unit (A-2) in the total of the structural unit A and the structural unit C is 50 mol% or less.
The polyamide-imide resin according to any one of claims 1 to 4, wherein the proportion of the structural unit (C-1) in the structural unit C is 50 mol% or more.
The polyamide-imide resin according to any one of claims 1 to 5, wherein the proportion of the structural unit (B-1) in the structural unit B is 50 mol% or more.
A polyamide-imide varnish obtained by dissolving the polyamide-imide resin according to any one of claims 1 to 6 in an organic solvent.
A polyamide-imide film comprising the polyamide-imide resin according to any one of claims 1 to 6.