CN113795383A

CN113795383A - Laminate

Info

Publication number: CN113795383A
Application number: CN202080033961.6A
Authority: CN
Inventors: 星野舜; 村山智寿; 安孙子洋平; 三田寺淳
Original assignee: Mitsubishi Gas Chemical Co Inc
Current assignee: Mitsubishi Gas Chemical Co Inc
Priority date: 2019-05-09
Filing date: 2020-04-23
Publication date: 2021-12-14
Also published as: KR20220007595A; JPWO2020226062A1; JP7632280B2; TW202105415A; WO2020226062A1

Abstract

A laminate wherein a polyimide film is laminated on a glass substrate or a silicon substrate, and a metal film or an oxide semiconductor film is further laminated on the polyimide film, wherein the metal film or the oxide semiconductor film has a thickness of 1 to 400nm, and the polyimide film has a moisture content of 1,000 to 35,000 ppm by mass.

Description

Laminated body

Technical Field

The present invention relates to a laminate, and more particularly, to a laminate in which a polyimide film is closely adhered to a glass substrate or a silicon substrate, and a metal film or an oxide semiconductor film is further laminated on the polyimide film.

Background

Polyimide resins have been variously used in the fields of electric and electronic components and the like. For example, for the purpose of weight reduction and flexibility of devices, it is desired to replace glass substrates used in image display devices such as liquid crystal displays and OLED displays with plastic substrates, and studies on polyimide films suitable for the plastic substrates have been advanced.

In an image display device, when light emitted from a display element passes through a plastic substrate and is emitted, the plastic substrate is required to have colorless transparency, and when light passes through a retardation film or a polarizing plate (for example, a liquid crystal display, a touch panel, or the like), high optical isotropy (that is, low Rth) is required in addition to the colorless transparency.

When a polyimide film is used as a substrate, a desired electronic circuit is formed on the polyimide film through various steps such as a sputtering step and an etching step for forming an oxide semiconductor film such as an Indium Tin Oxide (ITO) film, depending on the application. In order to ensure flatness of a polyimide film when a desired electronic circuit is formed on the polyimide film, the polyimide film is closely adhered to a hard support such as a glass plate. In this case, if the polyimide film is not adhered to the support, a process defect occurs. Further, after these processes, a step of peeling the polyimide film from the support is required. The peeling step is performed after the molded body on the base material is cooled to about room temperature to 50 ℃.

As a method for bonding a polyimide film to a support, in addition to a method of adding an adhesive to polyimide itself, a method of inserting a layer called a release layer between a polyimide film and a support to secure bonding in a process, and the like are known.

As a method for peeling the polyimide film from the support, for example, the following methods are known.

(1) A method of obtaining a structure comprising a polyimide resin and a support, and then irradiating the structure with a laser beam from the support side to ablate the polyimide resin interface, thereby peeling the polyimide resin (see, for example, patent document 1). Examples of the laser include solid-state (YAG) laser and gas (UV excimer) laser, and a spectrum of 308nm or the like is used.

(2) A method of forming a release layer on a support before applying a resin composition to the support, obtaining a structure comprising a polyimide resin film/release layer/support, and mechanically releasing the polyimide resin film (see, for example, patent document 2). Examples of the release layer include a method using Parylene (registered trademark, manufactured by Parylene Japan k.k.), tungsten oxide, and a method using a vegetable oil-based, silicone-based, fluorine-based, or alkoxide-based release agent. In addition, the laser beam described in (1) above may be irradiated in combination.

Further, patent document 3 discloses the following method: in the method of fixing a resin substrate to a support substrate via an adhesive layer, forming an electronic element on the resin substrate, and peeling an electronic component including the electronic element and the resin substrate from the support substrate, the adhesive layer mainly contains a material whose adhesive force with the support substrate is reduced by contact with moisture.

On the other hand, patent document 4 discloses: the water content in the resin composition containing the polyimide precursor and the organic solvent is reduced from the viewpoint of imidization of the polyamic acid and the viewpoint of storage stability of the resin composition. That is, it is considered that a part of the acid anhydride groups of the acid dianhydride monomer are hydrolyzed into carboxyl groups by the influence of moisture, and remain in a low molecular weight state without increasing the molecular weight. In addition, it is considered that moisture is involved in decomposition and re-bonding of the polyimide precursor, and affects the viscosity stability of the resin composition during storage.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication No. 2007-512568

Patent document 2: japanese laid-open patent publication No. 2010-067957

Patent document 3: japanese patent laid-open publication No. 2016-021384

Patent document 4: japanese patent laid-open publication No. 2018-145440

Disclosure of Invention

Problems to be solved by the invention

In the method (1), there is a problem that the resin substrate formed on the base is damaged during laser irradiation. In addition, an expensive laser irradiation device must be introduced, which causes a problem of cost.

In the method (2), although a laser irradiation device is not required, the release layer may not sufficiently function depending on the type of polyimide.

In the method of patent document 3, in order to prevent the adhesive layer from contacting moisture and to prevent the adhesive force from decreasing when forming the electronic component, it is necessary to form a sealing layer for sealing the exposed portion of the adhesive layer. On the other hand, when the electronic device is peeled off after the electronic element is formed, the sealing layer needs to be removed before peeling in order to bring moisture into contact with the adhesive layer. Therefore, the method of patent document 3 is a complicated process as a whole. Further, in order to contact with moisture, it is necessary to install the separator in a high humidity environment having a humidity of 90% or more, and there is a problem that it is difficult to control the moisture content and to ensure stable peelability.

The present invention has been made in view of such circumstances, and provides a laminate in which a polyimide film is laminated on a glass substrate or a silicon substrate, and a metal film or an oxide semiconductor film is further laminated on the polyimide film, which is excellent in colorless transparency and optical isotropy, and which can be easily and stably peeled from the glass substrate or the silicon substrate.

Means for solving the problems

The present inventors have surprisingly found that: the above problems can be solved by intentionally adding an optimum amount of moisture, which has been required to be reduced in the past, to the film. The present invention has been completed based on such findings.

Namely, the present invention relates to the following.

[ claim 1] A laminate wherein a polyimide film is laminated on a glass substrate or a silicon substrate, and a metal film or an oxide semiconductor film is further laminated on the polyimide film, wherein the metal film or the oxide semiconductor film has a thickness of 1 to 400nm, and the polyimide film has a moisture content of 1,000 to 35,000 ppm by mass.

<2> the laminate according to <1>, wherein the polyimide film has a peel strength from a glass substrate or a silicon substrate of 20gf/cm or less.

<3> the laminate according to <1> or <2>, wherein the polyimide film has a film thickness of 3 to 20 μm.

<4> the laminate according to any one of <1> to <3>, wherein the oxide semiconductor film is at least 1 selected from the group consisting of indium tin oxide, amorphous silicon, indium gallium zinc oxide, and low temperature polysilicon.

<5> an electroconductive thin film obtained by peeling and removing the glass substrate or the silicon substrate from the laminate according to any one of <1> to <4 >.

<6> a method for manufacturing a conductive thin film, comprising:

a step of laminating a polyimide film on a glass substrate or a silicon substrate;

adjusting the moisture content of the polyimide film to 1,000 to 35,000 mass ppm;

a step of laminating a metal film or an oxide semiconductor film having a thickness of 1 to 400nm on the polyimide film; and

and a step of peeling off and removing the glass substrate or the silicon substrate.

<7> the method for producing a conductive thin film according to <6>, wherein the step of adjusting the moisture content of the polyimide film is a step of holding the polyimide film in a temperature and humidity environment of 10 to 40 ℃ and 40 to 80% RH for 20 hours or more.

<8> the method for manufacturing a conductive thin film according to <6> or <7>, wherein the step of laminating a metal film or an oxide semiconductor film on the polyimide film is a physical vapor deposition method or a chemical vapor deposition method.

ADVANTAGEOUS EFFECTS OF INVENTION

The laminate of the present invention can be easily and stably peeled even when the polyimide film is mechanically peeled from the glass substrate or the silicon substrate. Therefore, the laminate of the present invention can contribute to simplification of the manufacturing process of a flexible electronic device provided with a resin substrate, improvement of the yield thereof, and the like.

The polyimide film is excellent in colorless transparency and optical isotropy. Therefore, the thin film peeled from the glass substrate or the silicon substrate is suitable as a resin substrate for a flexible electronic device.

Detailed Description

Hereinafter, an embodiment of the present invention will be described. The present invention is not limited to the embodiments described below.

In the present specification, the term "a to B" used in the description of numerical values means "a to B inclusive" (in the case of a < B) or "a to B inclusive" (in the case of a > B). In the present invention, a combination of preferred embodiments is a more preferred embodiment.

In the laminate of the present invention, a polyimide film is laminated on a glass substrate or a silicon substrate, and a metal film or an oxide semiconductor film is further laminated on the polyimide film, wherein the thickness of the metal film or the oxide semiconductor film is 1 to 400nm, and the moisture content of the polyimide film is 1,000 to 35,000 ppm by mass.

(glass substrate or silicon substrate)

The glass substrate or the silicon substrate is not particularly limited as long as it has a strength enough to support the polyimide film when manufacturing an electronic device (conductive film) having the polyimide film as a substrate. The type of glass is not particularly limited, and alkali-free glass (borosilicate glass), alkali glass, soda-lime glass, non-fluorescent glass, phosphate glass, borate glass, quartz, and the like can be used.

In order to improve adhesion to the polyimide film, the upper surface of the glass substrate or the silicon substrate is preferably highly flat. Specifically, the surface roughness Rmax is preferably 10 μm or less, and Rmax is more preferably 1 μm or less.

(polyimide film)

In the laminate of the present invention, the polyimide film is bonded to the glass substrate or the silicon substrate. The polyimide film is preferably directly bonded to the glass substrate or the silicon substrate, and an adhesive layer or the like is preferably not interposed between the glass substrate or the silicon substrate and the polyimide film.

The polyimide film of the present invention has a moisture content of 1,000 to 35,000 mass ppm, preferably 3,000 to 30,000 mass ppm, and more preferably 5,000 to 25,000 mass ppm. When the moisture content of the polyimide film is within this range, the polyimide film can be stably peeled from the glass substrate or the silicon substrate after the electronic device is manufactured.

The film thickness of the polyimide film is preferably 3 to 20 μm, more preferably 4 to 15 μm, and further preferably 5 to 10 μm. When the film thickness of the polyimide film is within this range, the polyimide film is not damaged during the production of the electronic device, the production of the electronic device is easy, and the polyimide film can be stably peeled from the glass substrate or the silicon substrate after the production of the electronic device. The film thickness of the polyimide film may be measured physically using a micrometer or the like, or may be determined by measuring the height of the contact surface between the upper surface of the film and the glass by optical observation using a laser microscope or the like.

The polyimide film preferably has a peel strength from a glass substrate or a silicon substrate of 20gf/cm or less, more preferably 15gf/cm or less, and still more preferably 10gf/cm or less. When the peel strength is within this range, the polyimide film adheres to the glass substrate or the silicon substrate without peeling during the production of the electronic device, and can be stably peeled from the glass substrate or the silicon substrate after the production of the electronic device.

The polyimide film of the present invention is excellent in colorless transparency and optical isotropy. Suitable physical property values of the polyimide film in the present invention are as follows.

When a film having a thickness of 10 μm is used, the total light transmittance is preferably 88% or more, more preferably 88.5% or more, and still more preferably 89% or more. The Yellow Index (YI) is preferably 4.0 or less, more preferably 2.5 or less, and still more preferably 2.0 or less when a film having a thickness of 10 μm is used. For b^*When a thin film having a thickness of 10 μm is used, it is preferably 2.0 or less, more preferably 1.2 or less, and still more preferably 1.0 or less.

When a film having a thickness of 10 μm is used as the absolute value of the retardation by thickness (Rth), it is preferably 100nm or less, more preferably 60nm or less, and still more preferably 35nm or less. When the amount is within this range, the optical isotropy is excellent.

The tensile strength is preferably 60MPa or more, more preferably 70MPa or more, and still more preferably 80MPa or more. The tensile modulus is preferably 2.0GPa or more, more preferably 2.5GPa or more, and still more preferably 3.0GPa or more.

The glass transition temperature (Tg) of the polyimide resin constituting the polyimide film in the present invention is preferably 230 ℃ or higher, more preferably 250 ℃ or higher, and still more preferably 270 ℃ or higher.

A preferred example of the polyimide resin usable in the present invention is shown, but the present invention is not limited thereto.

[ polyimide resin 1]

The polyimide resin 1 has a constituent unit A1 derived from a tetracarboxylic dianhydride and a constituent unit B1 derived from a diamine, the constituent unit A1 includes a constituent unit (A-11) derived from a compound represented by the following formula (a-11) and a constituent unit (A-12) derived from a compound represented by the following formula (a-12), and the constituent unit B1 includes a constituent unit (B-11) derived from a compound represented by the following formula (B-11) and a constituent unit (B-12) derived from a compound represented by the following formula (B-12).

< constituent Unit A1>

The constituent unit a1 is a constituent unit derived from a tetracarboxylic dianhydride in the polyimide resin 1, and includes a constituent unit (a-11) derived from a compound represented by the following formula (a-11) and a constituent unit (a-12) derived from a compound represented by the following formula (a-12).

The compound represented by the formula (a-11) is 1,2,4, 5-cyclohexanetetracarboxylic dianhydride.

The compound represented by the formula (a-12) is 4, 4' -oxydiphthalic anhydride.

By including both the constituent unit (A-11) and the constituent unit (A-12) in the constituent unit A1, the colorless transparency, optical isotropy, and chemical resistance of the film can be improved. The constituent unit (A-11) contributes greatly to the improvement of colorless transparency and optical isotropy in particular, and the constituent unit (A-12) contributes greatly to the improvement of chemical resistance in particular.

The proportion of the constituent unit (a-11) in the constituent unit a1 is preferably 5 to 95 mol%, more preferably 15 to 95 mol%, still more preferably 20 to 90 mol%, and particularly preferably 50 to 90 mol%.

The proportion of the constituent unit (a-12) in the constituent unit a1 is preferably 5 to 95 mol%, more preferably 5 to 85 mol%, still more preferably 10 to 80 mol%, and particularly preferably 10 to 50 mol%.

The ratio of the total of the constituent units (A-11) and (A-12) in the constituent unit A1 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 of the total ratio of the constituent units (A-11) and (A-12) is not particularly limited, i.e., 100 mol%. The constituent unit A1 may be formed of only the constituent unit (A-11) and the constituent unit (A-12).

The constituent unit A1 may include constituent units other than the constituent units (A-11) and (A-12). The tetracarboxylic dianhydride providing such a constituent unit is not particularly limited, and examples thereof include aromatic tetracarboxylic dianhydrides (excluding the compound represented by the formula (a-12)) such as pyromellitic dianhydride, 3 ', 4, 4' -biphenyltetracarboxylic dianhydride, 9 '-bis (3, 4-dicarboxyphenyl) fluorene dianhydride, and 4, 4' - (hexafluoroisopropylidene) phthalic anhydride; alicyclic tetracarboxylic dianhydrides such as 1,2,3, 4-cyclobutanetetracarboxylic dianhydride and norbornane-2-spiro- α -cyclopentanone- α' -spiro-2 ″ -norbornane-5, 5 ″,6,6 ″ -tetracarboxylic dianhydride (excluding the compound represented by the formula (a-11)); and aliphatic tetracarboxylic acid dianhydrides such as 1,2,3, 4-butanetetracarboxylic acid dianhydride.

In the present specification, an aromatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride containing 1 or more aromatic rings, an alicyclic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride containing 1 or more alicyclic rings and no aromatic rings, and an aliphatic tetracarboxylic dianhydride refers to a tetracarboxylic dianhydride containing neither aromatic rings nor alicyclic rings.

The number of constituent units (i.e., constituent units other than the constituent units (a-11) and (a-12)) included in the constituent unit a1 may be 1, or 2 or more.

< constituent Unit B1>

The constituent unit B1 is a diamine-derived constituent unit in the polyimide resin, and includes a constituent unit (B-11) derived from a compound represented by the following formula (B-11) and a constituent unit (B-12) derived from a compound represented by the following formula (B-12).

The compound represented by the formula (b-11) is 3, 3' -diaminodiphenyl sulfone.

By including the constituent unit (B-11) in the constituent unit B1, the optical isotropy and chemical resistance of the film can be improved.

The compound represented by the formula (b-12) is bis [4- (4-aminophenoxy) phenyl ] sulfone.

By including the constituent unit (B-12) in the constituent unit B1, the tensile elongation of the film can be improved.

The proportion of the constituent unit (B-11) in the constituent unit B1 is preferably 5 to 95 mol%, more preferably 15 to 95 mol%, still more preferably 20 to 90 mol%, and particularly preferably 50 to 90 mol%.

The proportion of the constituent unit (B-12) in the constituent unit B1 is preferably 5 to 95 mol%, more preferably 5 to 85 mol%, still more preferably 10 to 80 mol%, and particularly preferably 10 to 50 mol%.

The ratio of the total of the constituent units (B-11) and (B-12) in the constituent unit B1 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 of the total ratio of the constituent units (B-11) and (B-12) is not particularly limited, i.e., 100 mol%. The constituent unit B1 may be formed of only the constituent unit (B-11) and the constituent unit (B-12).

The constituent unit B1 may include constituent units other than the constituent units (B-11) and (B-12). The diamine providing such a constituent unit is not particularly limited, and examples thereof include 1, 4-phenylenediamine, p-xylylenediamine, 3, 5-diaminobenzoic acid, 1, 5-diaminonaphthalene, 2 '-dimethylbiphenyl-4, 4' -diamine, 2 '-bis (trifluoromethyl) benzidine, 4' -diaminodiphenyl ether, 4 '-diaminodiphenylmethane, 2-bis (4-aminophenyl) hexafluoropropane, 4' -diaminodiphenylsulfone, 4 '-diaminobenzanilide, 1- (4-aminophenyl) -2, 3-dihydro-1, 3, 3-trimethyl-1H-indene-5-amine, α' -bis (4-aminophenyl) -1, aromatic diamines such as 4-diisopropylbenzene, N '-bis (4-aminophenyl) terephthalamide, 4' -bis (4-aminophenoxy) biphenyl, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 9-bis (4-aminophenyl) fluorene, and 4,4 '-diamino-2, 2' -bistrifluoromethyldiphenyl ether (excluding compounds represented by the formula (b-11) or (b-12)); alicyclic diamines such as 1, 3-bis (aminomethyl) cyclohexane and 1, 4-bis (aminomethyl) cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.

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

Constituent units (i.e., constituent units other than constituent units (B-11) and (B-12)) arbitrarily contained in constituent unit B1 may be 1 type, or 2 or more types.

As the diamine that provides a constituent unit optionally contained in the constituent unit B1, a compound represented by the following formula (B-13-1), a compound represented by the following formula (B-13-2), a compound represented by the following formula (B-13-3), and a compound represented by the following formula (B-13-4) are preferable. That is, in the polyimide resin according to one embodiment of the present invention, the constituent unit B1 may further include a constituent unit (B-13), and the constituent unit (B-13) is at least 1 selected from the group consisting of a constituent unit (B-13-1) derived from a compound represented by the following formula (B-13-1), a constituent unit (B-13-2) derived from a compound represented by the following formula (B-13-2), a constituent unit (B-13-3) derived from a compound represented by the following formula (B-13-3), and a constituent unit (B-13-4) derived from a compound represented by the following formula (B-13-4).

(in the formula (b-13-2), R is each independently a hydrogen atom, a fluorine atom or a methyl group.)

The compound represented by the formula (b-13-1) is 2,2 '-bis (trifluoromethyl) -4, 4' -diaminodiphenyl ether (6 FODA).

When the constituent unit B1 contains the constituent unit (B-13-1), the colorless transparency of the film can be improved.

In the formula (b-13-2), R is independently selected from the group consisting of a hydrogen atom, a fluorine atom and an alkyl group having 1 to 5 carbon atoms, is a hydrogen atom, a fluorine atom or a methyl group, and is preferably a hydrogen atom. Examples of the compound represented by the formula (b-13-2) include 9, 9-bis (4-aminophenyl) fluorene, 9-bis (3-fluoro-4-aminophenyl) fluorene, and 9, 9-bis (3-methyl-4-aminophenyl) fluorene, and preferably at least 1 selected from the group consisting of these 3 compounds, and more preferably 9, 9-bis (4-aminophenyl) fluorene.

By including the constituent unit (B-13-2) in the constituent unit B1, the optical isotropy and heat resistance of the film can be improved.

The compound represented by the formula (b-13-3) is 2, 2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane.

When the constituent unit B1 contains the constituent unit (B-13-3), the colorless transparency of the film can be improved.

The compound represented by the formula (b-13-4) is 2, 2' -bis (trifluoromethyl) benzidine.

By including the constituent unit (B-13-4) in the constituent unit B1, the colorless transparency, chemical resistance, and mechanical properties of the film can be improved.

When the constituent unit B1 includes the constituent unit (B-11), the constituent unit (B-12) and the constituent unit (B-13), the total ratio of the constituent unit (B-11) and the constituent unit (B-12) in the constituent unit B1 is preferably 70 to 95 mol%, more preferably 75 to 95 mol%, and still more preferably 75 to 90 mol%, and the ratio of the constituent unit (B-13) in the constituent unit B1 is preferably 5 to 30 mol%, more preferably 5 to 25 mol%, and still more preferably 10 to 25 mol%.

The total ratio of the constituent unit (B-11), the constituent unit (B-12) and the constituent unit (B-13) in the constituent unit B1 is preferably 75 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio of the total of the constituent unit (B-11), the constituent unit (B-12) and the constituent unit (B-13) is not particularly limited, i.e., 100 mol%. The constituent unit B1 may be formed of only the constituent unit (B-11), the constituent unit (B-12) and the constituent unit (B-13).

The constituent unit (B-13) may be only the constituent unit (B-13-1), only the constituent unit (B-13-2), only the constituent unit (B-13-3), or only the constituent unit (B-13-4).

Further, the constituent unit (B-13) may be a combination of 2 or more constituent units selected from the group consisting of the constituent units (B-13-1) to (B-13-4).

The number average molecular weight of the polyimide resin 1 is preferably 5,000 to 200,000 from the viewpoint of the mechanical strength of the polyimide film to be obtained. 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 permeation chromatography.

The polyimide resin 1 may contain a structure other than a polyimide chain (a structure in which the constituent unit a1 and the constituent unit B1 are imide-bonded). Examples of the structure other than the polyimide chain that can be contained in the polyimide resin include a structure containing an amide bond.

The polyimide resin 1 preferably contains a polyimide chain (a structure in which the constituent unit a1 and the constituent unit B1 are imide-bonded) as a main structure. Therefore, the ratio of the polyimide chain in the polyimide resin 1 is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 99% by mass or more.

[ method for producing polyimide resin 1]

The polyimide resin 1 can be produced by reacting a tetracarboxylic acid component containing a compound that provides the constituent unit (a-11) and a compound that provides the constituent unit (a-12) with a diamine component containing a compound that provides the constituent unit (B-11) and a compound that provides the constituent unit (B-12).

Examples of the compound that provides the constituent unit (A-11) include compounds represented by the formula (a-11), but the compound is not limited thereto, and derivatives thereof may be provided within a range that provides the same constituent unit. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-11) (i.e., 1,2,4, 5-cyclohexanetetracarboxylic acid) and an alkyl ester of the tetracarboxylic acid. As the compound providing the constituent unit (A-11), a compound represented by the formula (a-11) (i.e., dianhydride) is preferred.

Similarly, examples of the compound which provides the constituent unit (A-12) include compounds represented by the formula (a-12), but the compound is not limited thereto, and derivatives thereof may be included within the range in which the same constituent unit is provided. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-12) and an alkyl ester of the tetracarboxylic acid. As the compound providing the constituent unit (A-12), a compound represented by the formula (a-12) (i.e., dianhydride) is preferred.

The tetracarboxylic acid component contains the compound that provides the constituent unit (a-11) preferably in a range of 5 to 95 mol%, more preferably in a range of 15 to 95 mol%, even more preferably in a range of 20 to 90 mol%, and particularly preferably in a range of 50 to 90 mol%.

The tetracarboxylic acid component contains the compound that provides the constituent unit (a-12) preferably in a range of 5 to 95 mol%, more preferably in a range of 5 to 85 mol%, even more preferably in a range of 10 to 80 mol%, and particularly preferably in a range of 10 to 50 mol%.

The tetracarboxylic acid component contains the compound that provides the constituent unit (A-11) and the compound that provides the constituent unit (A-12) in total preferably at least 50 mol%, more preferably at least 70 mol%, even more preferably at least 90 mol%, and particularly preferably at least 99 mol%. The upper limit of the total content ratio of the compound that provides the constituent unit (A-11) and the compound that provides the constituent unit (A-12) is not particularly limited, i.e., 100 mol%. The tetracarboxylic acid component may be formed only from the compound which provides the constituent unit (A-11) and the compound which provides the constituent unit (A-12).

The tetracarboxylic acid component may contain compounds other than the compound providing the constituent unit (a-11) and the compound providing the constituent unit (a-12), and examples of the compounds include the above-mentioned aromatic tetracarboxylic acid dianhydride, alicyclic tetracarboxylic acid dianhydride, and aliphatic tetracarboxylic acid dianhydride, and derivatives thereof (e.g., tetracarboxylic acid, alkyl ester of tetracarboxylic acid, etc.).

The number of the compounds (i.e., compounds other than the compound providing the constituent unit (A-11) and the compound providing the constituent unit (A-12)) contained in the tetracarboxylic acid component may be 1, or 2 or more.

The compound that provides the constituent unit (B-11) is not limited to the compound represented by the formula (B-11), and derivatives thereof may be used as long as the same constituent unit is provided. Examples of the derivative include diisocyanates corresponding to the diamines represented by the formula (b-11). As the compound providing the constituent unit (B-11), a compound represented by the formula (B-11) (i.e., diamine) is preferable.

The compound that provides the constituent unit (B-12) includes, but is not limited to, the compound represented by the formula (B-12), and derivatives thereof may be included within the range that provides the same constituent unit. Examples of the derivative include diisocyanates corresponding to the diamines represented by the formula (b-12). As the compound providing the constituent unit (B-12), a compound represented by the formula (B-12) (i.e., diamine) is preferable.

The diamine component contains the constituent unit (B-11) preferably in a range of 5 to 95 mol%, more preferably in a range of 15 to 95 mol%, even more preferably in a range of 20 to 90 mol%, and particularly preferably in a range of 50 to 90 mol%.

The diamine component contains the constituent unit (B-12) preferably at 5 to 95 mol%, more preferably at 5 to 85 mol%, even more preferably at 10 to 80 mol%, and particularly preferably at 10 to 50 mol%.

The diamine component contains the constituent units (B-11) and (B-12) in a total amount of 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 of the total ratio of the constituent units (B-11) and (B-12) is not particularly limited, i.e., 100 mol%. The diamine component may be formed only from the constituent unit (B-11) and the constituent unit (B-12).

The diamine component may contain compounds other than the compound that provides the constituent unit (B-11) and the compound that provides the constituent unit (B-12), and examples of the compounds include the above-mentioned aromatic diamine, alicyclic diamine, and aliphatic diamine, and derivatives thereof (e.g., diisocyanate).

The number of compounds (i.e., compounds other than the compound that provides the constituent unit (B-11) and the compound that provides the constituent unit (B-12)) optionally contained in the diamine component may be 1, or 2 or more.

As the compound optionally contained in the diamine component, a compound which can provide the constituent unit (B-13) (i.e., a compound which can provide the constituent unit (B-13-1), a compound which can provide the constituent unit (B-13-2), a compound which can provide the constituent unit (B-13-3), and a compound which can provide the constituent unit (B-13-4)) are preferable.

Examples of the compound that can provide the constituent unit (B-13) include compounds represented by the formula (B-13-1), compounds represented by the formula (B-13-2), compounds represented by the formula (B-13-3), and compounds represented by the formula (B-13-4), but are not limited thereto, and derivatives thereof may be included as long as they can form the same constituent unit. Examples of the derivative include diisocyanates corresponding to diamines represented by the formulae (b-13-1) to (b-13-4). As the compound providing the constituent unit (B-13), compounds represented by the formulae (B-13-1) to (B-13-4) (i.e., diamines) are preferable.

When the diamine component contains the compound that provides the constituent unit (B-11), the compound that provides the constituent unit (B-12), and the compound that provides the constituent unit (B-13), the total amount of the compound that provides the constituent unit (B-11) and the compound that provides the constituent unit (B-12) in the diamine component is preferably 70 to 95 mol%, more preferably 75 to 95 mol%, and still more preferably 75 to 90 mol%, and the amount of the compound that provides the constituent unit (B-13) is preferably 5 to 30 mol%, more preferably 5 to 25 mol%, and still more preferably 10 to 25 mol%.

The diamine component contains the compound that provides the constituent unit (B-11), the compound that provides the constituent unit (B-12), and the compound that provides the constituent unit (B-13) in total preferably at least 75 mol%, more preferably at least 80 mol%, still more preferably at least 90 mol%, and particularly preferably at least 99 mol%. The upper limit of the total content ratio of the compound that provides the constituent unit (B-11), the compound that provides the constituent unit (B-12), and the compound that provides the constituent unit (B-13) is not particularly limited, i.e., 100 mol%. The diamine component may be formed only of the compound that provides the constituent unit (B-11), the compound that provides the constituent unit (B-12), and the compound that provides the constituent unit (B-13).

The compound that provides the constituent unit (B-13) may be only the compound that provides the constituent unit (B-13-1), may be only the compound that provides the constituent unit (B-13-2), may be only the compound that provides the constituent unit (B-13-3), or may be only the compound that provides the constituent unit (B-13-4).

The compound that provides the constituent unit (B-13) may be a combination of 2 or more compounds selected from the group consisting of the compounds that provide the constituent units (B-13-1) to (B-13-4).

The amount ratio of the tetracarboxylic acid component to the diamine component to be used for producing the polyimide resin 1 is preferably 0.9 to 1.1 mol of the diamine component relative to 1 mol of the tetracarboxylic acid component.

In addition, in the production of the polyimide resin 1, an end-capping agent may be used in addition to the tetracarboxylic acid component and the diamine component described above. As the blocking agent, monoamines or dicarboxylic acids are preferred. The amount of the end-capping agent to be introduced is preferably 0.0001 to 0.1 mol, and particularly preferably 0.001 to 0.06 mol, based on 1 mol of the tetracarboxylic acid component. As the blocking agent of the monoamine type, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline and the like are recommended. Among these, benzylamine and aniline can be suitably used. As the dicarboxylic acid-based end capping agent, dicarboxylic acids are preferred, and a part of the ring closure may be carried out. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2, 3-benzophenonedicarboxylic acid, 3, 4-benzophenonedicarboxylic acid, cyclopentane-1, 2-dicarboxylic acid, 4-cyclohexene-1, 2-dicarboxylic acid, and the like are recommended. Among 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.

Specific reaction methods include: (1) a method in which a tetracarboxylic acid component, a diamine component, and a reaction solvent are charged into a reactor, stirred at room temperature to 80 ℃ for 0.5 to 30 hours, and then heated to effect imidization; (2) a method in which a diamine component and a reaction solvent are put into a reactor and dissolved, and then a tetracarboxylic acid component is put into the reactor, and stirring is performed at room temperature to 80 ℃ for 0.5 to 30 hours if necessary, followed by heating to perform imidization; (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.

The reaction solvent used for producing the polyimide resin 1 may be any solvent that can dissolve the polyimide resin produced without inhibiting the imidization reaction. Examples thereof include aprotic solvents, phenol solvents, ether solvents, and carbonate solvents.

Specific examples of the aprotic solvent include amide solvents such as N, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 1, 3-dimethylimidazolidinone, and tetramethylurea, lactone solvents such as γ -butyrolactone and γ -valerolactone, phosphorus-containing amide solvents such as hexamethylphosphoramide and hexamethylphosphinotriamide, sulfur-containing solvents such as dimethylsulfone, dimethylsulfoxide, and sulfolane, 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, and 3, 5-xylenol.

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

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

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

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

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

Examples of the base catalyst include organic base catalysts such as pyridine, quinoline, isoquinoline, α -picoline, β -picoline, 2, 4-dimethylpyridine, 2, 6-dimethylpyridine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N-dimethylaniline and N, N-diethylaniline, and inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium 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, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, and the like. The imidization catalyst can be used singly or in combination of 2 or more.

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

The temperature of the imidization reaction is preferably 120 to 250 ℃ and more preferably 160 to 200 ℃ from the viewpoint of suppressing the reactivity, gelation, and the like. The reaction time is preferably 0.5 to 10 hours after the start of distillation of the product water.

The solid content concentration during the imidization reaction is preferably 30 to 60 mass%, more preferably 35 to 58 mass%, and particularly preferably 40 to 56 mass%. When the solid content concentration during the imidization reaction is within this range, the imidization reaction proceeds well, and water produced during the reaction can be easily removed, so that the degree of polymerization and the imidization rate can be increased.

The solid content concentration during the imidization reaction is a value calculated by the following formula based on the mass of the tetracarboxylic acid component added to the reaction system, the diamine component in the reaction system, and the reaction solvent.

The solid content concentration (mass%) at the time of the imidization reaction ═ mass of the total of the tetracarboxylic acid component and the diamine component)/(mass of the total of the tetracarboxylic acid component, the diamine component, and the reaction solvent) × 100

Further, another preferable example of the polyimide resin usable in the present invention is shown, but the present invention is not limited thereto.

[ polyimide resin 2]

The polyimide resin 2 has a constituent unit A2 derived from a tetracarboxylic dianhydride and a constituent unit B2 derived from a diamine, the constituent unit A2 includes a constituent unit (A-21) derived from a compound represented by the following formula (a-21) and a constituent unit (A-22) derived from a compound represented by the following formula (a-22), the constituent unit B2 includes a constituent unit (B-21) derived from a compound represented by the following formula (B-21), and the ratio of the constituent unit (B-21) in the constituent unit B2 is 70 mol% or more.

< constituent Unit A2>

The constituent unit a2 is a constituent unit derived from a tetracarboxylic dianhydride in the polyimide resin 2, and includes a constituent unit (a-21) derived from a compound represented by the formula (a-21) and a constituent unit (a-22) derived from a compound represented by the formula (a-22). The compound represented by the formula (a-21) is the same as the compound represented by the formula (a-11). The compound represented by the formula (a-22) is the same as the compound represented by the formula (a-12).

By including both the constituent unit (A-21) and the constituent unit (A-22) in the constituent unit A2, the colorless transparency, optical isotropy, and chemical resistance of the film can be improved. The constituent unit (A-21) contributes greatly to improvement of colorless transparency and optical isotropy, and the constituent unit (A-22) contributes greatly to improvement of chemical resistance.

The proportion of the constituent unit (a-21) in the constituent unit a2 is preferably 5 to 95 mol%, more preferably 15 to 95 mol%, still more preferably 20 to 90 mol%, and particularly preferably 50 to 90 mol%.

The proportion of the constituent unit (a-22) in the constituent unit a2 is preferably 5 to 95 mol%, more preferably 5 to 85 mol%, still more preferably 10 to 80 mol%, and particularly preferably 10 to 50 mol%.

The ratio of the total of the constituent units (a-21) and (a-22) in the constituent unit a2 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 of the total ratio of the constituent units (A-21) and (A-22) is not particularly limited, i.e., 100 mol%. The constituent unit a2 may be formed of only the constituent unit (a-21) and the constituent unit (a-22).

The constituent unit a2 may include constituent units other than the constituent units (a-21) and (a-22). The tetracarboxylic dianhydrides providing such constituent units are not particularly limited, and include aromatic tetracarboxylic dianhydrides (excluding the compound represented by the formula (a-22)) such as pyromellitic dianhydride, 3 ', 4, 4' -biphenyltetracarboxylic dianhydride, 9 '-bis (3, 4-dicarboxyphenyl) fluorene dianhydride, and 4, 4' - (hexafluoroisopropylidene) phthalic anhydride; alicyclic tetracarboxylic dianhydrides such as 1,2,3, 4-cyclobutanetetracarboxylic dianhydride and norbornane-2-spiro- α -cyclopentanone- α' -spiro-2 ″ -norbornane-5, 5 ″,6,6 ″ -tetracarboxylic dianhydride (excluding the compound represented by formula (a-21)); and aliphatic tetracarboxylic acid dianhydrides such as 1,2,3, 4-butanetetracarboxylic acid dianhydride.

The number of constituent units included in the constituent unit a2 (i.e., constituent units other than the constituent units (a-21) and (a-22)) may be 1, or 2 or more.

< constituent Unit B2>

The constituent unit B2 is a diamine-derived constituent unit in the polyimide resin, and includes the constituent unit (B-21) derived from the compound represented by the formula (B-21). The compound represented by the formula (b-21) is the same as the compound represented by the formula (b-11).

By including the constituent unit (B-21) in the constituent unit B2, the optical isotropy and chemical resistance of the film can be improved.

The proportion of the constituent unit (B-21) in the constituent unit B2 is 70 mol% or more. This ratio is preferably 75 mol% or more, and more preferably 80 mol% or more. The upper limit of the ratio of the constituent unit (B-21) may be 90 mol%, 95 mol%, 99 mol%, or 100 mol%. The constituent unit B2 may be formed of only the constituent unit (B-21).

The constituent unit B2 may contain a constituent unit other than the constituent unit (B-21). The diamine providing such a constituent unit is not particularly limited, and examples thereof include 1, 4-phenylenediamine, p-xylylenediamine, 3, 5-diaminobenzoic acid, 1, 5-diaminonaphthalene, 2 '-dimethylbiphenyl-4, 4' -diamine, 2 '-bis (trifluoromethyl) benzidine, 4' -diaminodiphenyl ether, 4 '-diaminodiphenylmethane, 2-bis (4-aminophenyl) hexafluoropropane, 4' -diaminodiphenylsulfone, 4 '-diaminobenzanilide, 1- (4-aminophenyl) -2, 3-dihydro-1, 3, 3-trimethyl-1H-indene-5-amine, α' -bis (4-aminophenyl) -1, aromatic diamines such as 4-diisopropylbenzene, N '-bis (4-aminophenyl) terephthalamide, 4' -bis (4-aminophenoxy) biphenyl, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 9-bis (4-aminophenyl) fluorene, and 4,4 '-diamino-2, 2' -bistrifluoromethyldiphenyl ether (excluding the compounds represented by the formula (b-21)); alicyclic diamines such as 1, 3-bis (aminomethyl) cyclohexane and 1, 4-bis (aminomethyl) cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.

The number of constituent units (i.e., constituent units other than constituent unit (B-21)) arbitrarily contained in constituent unit B2 may be 1, or 2 or more.

As the diamine that provides a constituent unit optionally contained in the constituent unit B2, a compound represented by the following formula (B-22-1), a compound represented by the following formula (B-22-2), a compound represented by the following formula (B-22-3), and a compound represented by the following formula (B-22-4) are preferable. That is, in the polyimide resin according to one embodiment of the present invention, the constituent unit B2 may further include a constituent unit (B-22), and the constituent unit (B-22) is at least 1 selected from the group consisting of a constituent unit (B-22-1) derived from a compound represented by the following formula (B-22-1), a constituent unit (B-22-2) derived from a compound represented by the following formula (B-22-2), a constituent unit (B-22-3) derived from a compound represented by the following formula (B-22-3), and a constituent unit (B-22-4) derived from a compound represented by the following formula (B-22-4).

(in the formula (b-22-2), R is each independently a hydrogen atom, a fluorine atom or a methyl group.)

The compound represented by the formula (b-22-1) is the same as the compound represented by the formula (b-13-1).

By including the constituent unit (B-22-1) in the constituent unit B, the colorless transparency of the film can be improved.

The compound represented by the formula (b-22-2) is the same as the compound represented by the formula (b-13-2) described above, and the preferred ranges are the same.

By including the constituent unit (B-22-2) in the constituent unit B2, the optical isotropy and heat resistance of the film can be improved.

The compound represented by the formula (b-22-3) is the same as the compound represented by the formula (b-13-3).

When the constituent unit B2 contains the constituent unit (B-22-3), the colorless transparency of the film can be improved.

The compound represented by the formula (b-22-4) is the same as the compound represented by the above-mentioned formula (b-13-4).

By including the constituent unit (B-22-4) in the constituent unit B2, the colorless transparency, chemical resistance and mechanical properties of the film can be improved.

When the constituent unit B2 includes the constituent unit (B-21) and the constituent unit (B-22), the ratio of the constituent unit (B-21) in the constituent unit B2 is preferably 70 to 95 mol%, more preferably 75 to 95 mol%, and still more preferably 75 to 90 mol%, and the ratio of the constituent unit (B-22) in the constituent unit B2 is preferably 5 to 30 mol%, more preferably 5 to 25 mol%, and still more preferably 10 to 25 mol%.

The ratio of the total of the constituent unit (B-21) and the constituent unit (B-22) in the constituent unit B2 is preferably 75 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the total ratio of the constituent unit (B-21) and the constituent unit (B-22) is not particularly limited, i.e., 100 mol%. The constituent unit B may be formed of only the constituent unit (B-21) and the constituent unit (B-22).

The constituent unit (B-22) may be only the constituent unit (B-22-1), only the constituent unit (B-22-2), only the constituent unit (B-22-3), or only the constituent unit (B-22-4).

The constituent unit (B-22) may be a combination of 2 or more constituent units selected from the group consisting of the constituent units (B-22-1) to (B-22-4).

The number average molecular weight of the polyimide resin 2 is preferably 5,000 to 200,000 from the viewpoint of the mechanical strength of the polyimide film to be obtained.

The polyimide resin 2 may contain a structure other than a polyimide chain (a structure in which the constituent unit a2 and the constituent unit B2 are imide-bonded). Examples of the structure other than the polyimide chain that can be contained in the polyimide resin include a structure containing an amide bond.

The polyimide resin 2 preferably has a main structure of a polyimide chain (a structure in which the constituent unit a2 and the constituent unit B2 are imide-bonded). Therefore, the ratio of the polyimide chain in the polyimide resin 2 is preferably 50% by mass or more, more preferably 70% by mass or more, further preferably 90% by mass or more, and particularly preferably 99% by mass or more.

[ method for producing polyimide resin 2]

The polyimide resin can be produced by reacting a tetracarboxylic acid component containing a compound that provides the constituent unit (a-21) and a compound that provides the constituent unit (a-22) with a diamine component containing 70 mol% or more of a compound that provides the constituent unit (B-21).

Examples of the compound that provides the constituent unit (A-21) include compounds represented by the formula (a-21), but the compound is not limited thereto, and derivatives thereof may be included within the range that provides the same constituent unit. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-21) (i.e., 1,2,4, 5-cyclohexanetetracarboxylic acid) and an alkyl ester of the tetracarboxylic acid. As the compound providing the constituent unit (A-21), a compound represented by the formula (a-21) (i.e., dianhydride) is preferred.

Similarly, examples of the compound which provides the constituent unit (A-22) include compounds represented by the formula (a-22), but the compound is not limited thereto, and derivatives thereof may be included within the range in which the same constituent unit is provided. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride represented by the formula (a-22) and an alkyl ester of the tetracarboxylic acid. As the compound providing the constituent unit (A-22), a compound represented by the formula (a-22) (i.e., dianhydride) is preferred.

The tetracarboxylic acid component contains the compound that provides the constituent unit (a-21) preferably in a range of 5 to 95 mol%, more preferably in a range of 15 to 95 mol%, even more preferably in a range of 20 to 90 mol%, and particularly preferably in a range of 50 to 90 mol%.

The tetracarboxylic acid component contains the compound that provides the constituent unit (a-22) preferably in a range of 5 to 95 mol%, more preferably in a range of 5 to 85 mol%, even more preferably in a range of 10 to 80 mol%, and particularly preferably in a range of 10 to 50 mol%.

The tetracarboxylic acid component contains the compound that provides the constituent unit (A-21) and the compound that provides the constituent unit (A-22) in total preferably at least 50 mol%, more preferably at least 70 mol%, even more preferably at least 90 mol%, and particularly preferably at least 99 mol%. The upper limit of the total content ratio of the compound that provides the constituent unit (A-21) and the compound that provides the constituent unit (A-22) is not particularly limited, i.e., 100 mol%. The tetracarboxylic acid component may be formed only from the compound which provides the constituent unit (A-21) and the compound which provides the constituent unit (A-22).

The tetracarboxylic acid component may contain compounds other than the compound providing the constituent unit (a-21) and the compound providing the constituent unit (a-22), and examples of the compounds include the above-mentioned aromatic tetracarboxylic acid dianhydride, alicyclic tetracarboxylic acid dianhydride, and aliphatic tetracarboxylic acid dianhydride, and derivatives thereof (e.g., tetracarboxylic acid, alkyl ester of tetracarboxylic acid, etc.).

The number of the compounds (i.e., compounds other than the compound providing the constituent unit (A-21) and the compound providing the constituent unit (A-22)) contained in the tetracarboxylic acid component may be 1, or 2 or more.

Examples of the compound that provides the constituent unit (B-21) include compounds represented by the formula (B-21), but the compound is not limited thereto, and derivatives thereof may be included within the range that provides the same constituent unit. Examples of the derivative include diisocyanates corresponding to diamines represented by the formula (b-21). As the compound providing the constituent unit (B-21), a compound represented by the formula (B-21) (i.e., diamine) is preferable.

The diamine component contains 70 mol% or more of a compound that provides the constituent unit (B-21). The diamine component contains preferably 75 mol% or more, more preferably 80 mol% or more of a compound that provides the constituent unit (B-21). The upper limit of the content ratio of the compound constituting the unit (B-21) may be 90 mol%, 95 mol%, 99 mol%, or 100 mol%. The diamine component may be formed only from the compound that provides the constituent unit (B-21).

The diamine component may contain compounds other than the compound providing the constituent unit (B-21), and examples of the compounds include the above-mentioned aromatic diamine, alicyclic diamine, and aliphatic diamine, and derivatives thereof (e.g., diisocyanate).

The number of the compounds optionally contained in the diamine component (i.e., compounds other than the compound providing the constituent unit (B-21)) may be 1, or 2 or more.

As the compound optionally contained in the diamine component, a compound which can provide the constituent unit (B-22) (i.e., a compound which can provide the constituent unit (B-22-1), a compound which can provide the constituent unit (B-22-2), a compound which can provide the constituent unit (B-22-3), and a compound which can provide the constituent unit (B-22-4)) are preferable.

Examples of the compound that can provide the constituent unit (B-22) include compounds represented by the formula (B-22-1), compounds represented by the formula (B-22-2), compounds represented by the formula (B-22-3), and compounds represented by the formula (B-22-4), but are not limited thereto, and derivatives thereof may be included as long as the same constituent unit can be formed. Examples of the derivative include diisocyanates corresponding to diamines represented by the formulae (b-22-1) to (b-22-4). As the compound providing the constituent unit (B-22), compounds represented by the formulae (B-22-1) to (B-22-4) (i.e., diamines) are preferable.

When the diamine component contains the compound that provides the constituent unit (B-21) and the compound that provides the constituent unit (B-22), the diamine component contains the compound that provides the constituent unit (B-21) preferably at 70 to 95 mol%, more preferably at 75 to 95 mol%, and still more preferably at 75 to 90 mol%, and the compound that provides the constituent unit (B-22) preferably at 5 to 30 mol%, more preferably at 5 to 25 mol%, and still more preferably at 10 to 25 mol%.

The diamine component contains the compound that provides the constituent unit (B-21) and the compound that provides the constituent unit (B-22) in total preferably at least 75 mol%, more preferably at least 80 mol%, even more preferably at least 90 mol%, and particularly preferably at least 99 mol%. The upper limit of the total content ratio of the compound that provides the constituent unit (B-21) and the compound that provides the constituent unit (B-22) is not particularly limited, i.e., 100 mol%. The diamine component may be formed only of the compound that provides the constituent unit (B-21) and the compound that provides the constituent unit (B-22).

The compound that provides the constituent unit (B-22) may be only the compound that provides the constituent unit (B-22-1), may be only the compound that provides the constituent unit (B-22-2), may be only the compound that provides the constituent unit (B-22-3), or may be only the compound that provides the constituent unit (B-22-4).

The compound that provides the constituent unit (B-22) may be a combination of 2 or more compounds selected from the group consisting of the compounds that provide the constituent units (B-22-1) to (B-22-4).

The amount ratio of the tetracarboxylic acid component to the diamine component used for producing the polyimide resin 2 is preferably 0.9 to 1.1 mol of the diamine component relative to 1 mol of the tetracarboxylic acid component.

In addition, in the production of the polyimide resin 2, an end-capping agent may be used in addition to the tetracarboxylic acid component and the diamine component described above. As the end-capping agent, the same applies to the preferable range as described for the polyimide resin 1.

The method for reacting the tetracarboxylic acid component with the diamine component is not particularly limited, and a known method can be used. The specific reaction method is as described for the polyimide resin 1.

The reaction solvent used for producing the polyimide resin 2 may be any solvent that can dissolve the polyimide produced without inhibiting the imidization reaction. As a specific example of the reaction solvent, the same applies to the preferable range as described for the polyimide resin 1.

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

In the imidization reaction, a known imidization catalyst can be used. Specific examples of the imidization catalyst include the same preferable ranges as described for the polyimide resin 1.

Further, as another preferable example of the polyimide resin usable in the present invention, a polyimide resin obtained from the following copolymer can be exemplified, but the present invention is not limited thereto.

[ copolymer 3]

The copolymer 3 is a copolymer having a constituent unit A3 derived from tetracarboxylic dianhydride and a constituent unit B3 derived from diamine,

the constituent unit A3 is composed of a constituent unit (A-31) derived from an alicyclic tetracarboxylic dianhydride (a-31) and a constituent unit (A-32) derived from a tetracarboxylic dianhydride (a-32) other than the alicyclic tetracarboxylic dianhydride (a-31),

the constituent unit B3 contains a constituent unit (B-31) derived from a compound represented by the following formula (B-31),

the constituent unit (A-32) contains at least 1 selected from the group consisting of a constituent unit (A-32-1) derived from a compound represented by the following formula (a-32-1), a constituent unit (A-32-2) derived from a compound represented by the following formula (a-32-2), a constituent unit (A-32-3) derived from a compound represented by the following formula (a-32-3), and a constituent unit (A-32-4) derived from a compound represented by the following formula (a-32-4),

the copolymer has an imide repeating structural unit formed of a compound providing a constituent unit (A-31) and a compound providing a constituent unit (B-31), and has an amic acid repeating structural unit formed of a compound providing a constituent unit (A-32) and a compound providing a constituent unit B3.

< constituent Unit A3>

The constituent unit A3 is a constituent unit derived from a tetracarboxylic dianhydride in the copolymer 3, and is formed from a constituent unit (a-31) derived from an alicyclic tetracarboxylic dianhydride (a-31) and a constituent unit (a-32) derived from a tetracarboxylic dianhydride (a-32) other than an alicyclic tetracarboxylic dianhydride (a-31).

The constituent unit (A-31) is a constituent unit derived from an alicyclic tetracarboxylic dianhydride (a-31).

From the viewpoint of high transparency, high heat resistance and low residual stress, the constituent unit (A-31) preferably contains a constituent unit (A-31-1) derived from a compound represented by the following formula (a-31-1). The compound represented by the formula (a-31-1) is norbornane-2-spiro- α -cyclopentanone- α' -spiro-2 ″ -norbornane-5, 5 ″,6,6 ″ -tetracarboxylic dianhydride.

The proportion of the constituent unit (A-31-1) in the constituent unit (A-31) is preferably 45 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 of the ratio is not particularly limited, i.e., 100 mol%.

The constituent unit (A-31) may have a constituent unit derived from an alicyclic tetracarboxylic dianhydride other than the compound represented by the formula (a-31-1). Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 1,2,3, 4-cyclopentanetetracarboxylic dianhydride, 1,2,4, 5-cyclohexanetetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2, 3,5, 6-tetracarboxylic dianhydride, and dicyclohexyltetracarboxylic dianhydride.

The alicyclic tetracarboxylic dianhydride (a-31) may be 1 type alone or 2 or more types in combination.

The constituent unit (A-32) is a constituent unit derived from a tetracarboxylic dianhydride (a-32) other than the alicyclic tetracarboxylic dianhydride (a-31). The tetracarboxylic dianhydride (a-32) includes 1 or more selected from the group consisting of aromatic tetracarboxylic dianhydrides and aliphatic tetracarboxylic dianhydrides, and preferably includes an aromatic tetracarboxylic dianhydride. That is, the constituent unit (a-32) preferably contains a constituent unit derived from an aromatic tetracarboxylic dianhydride.

From the viewpoint of high heat resistance and low residual stress, the constituent unit (A-32) preferably contains at least 1 selected from the group consisting of a constituent unit (A-32-1) derived from a compound represented by the following formula (a-32-1), a constituent unit (A-32-2) derived from a compound represented by the following formula (a-32-2), a constituent unit (A-32-3) derived from a compound represented by the following formula (a-32-3), and a constituent unit (A-32-4) derived from a compound represented by the following formula (a-32-4).

The compound represented by the formula (a-32-1) is biphenyltetracarboxylic dianhydride (BPDA), and specific examples thereof include 3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride (s-BPDA) represented by the following formula (a-32-1s), 2,3,3 ', 4' -biphenyltetracarboxylic dianhydride (a-BPDA) represented by the following formula (a-32-1a), and 2,2 ', 3, 3' -biphenyltetracarboxylic dianhydride (i-BPDA) represented by the following formula (a-32-1 i). Among them, 3 ', 4, 4' -biphenyltetracarboxylic dianhydride (s-BPDA) represented by the following formula (a-32-1s) is preferable.

The compound represented by the formula (a-32-2) is p-phenylene bis (trimellitate) dianhydride (TAHQ).

The compound represented by the formula (a-32-3) is oxydiphthalic anhydride (ODPA), and specific examples thereof include 4,4 ' -oxydiphthalic anhydride (s-ODPA) represented by the following formula (a-32-3s), 3,4 ' -oxydiphthalic anhydride (a-ODPA) represented by the following formula (a-32-3a), and 3,3 ' -oxydiphthalic anhydride (i-ODPA) represented by the following formula (a-32-3 i). Among them, 4' -oxydiphthalic anhydride (s-ODPA) represented by the following formula (a-32-3s) is preferable.

The compound represented by the formula (a-32-4) is pyromellitic dianhydride (PMDA).

From the viewpoint of high heat resistance and low residual stress, the constituent unit (A-32) is preferably at least 1 selected from the group consisting of the constituent unit (A-32-1) and the constituent unit (A-32-2).

The constituent unit (A-32-1) is preferable from the viewpoint of improving the heat resistance and thermal stability of the film and further reducing the residual stress, and the constituent unit (A-32-2) is preferable from the viewpoint of reducing YI and further improving the colorless transparency.

The tetracarboxylic dianhydride (a-32) may contain a tetracarboxylic dianhydride other than the compounds represented by the formulae (a-32-1) to (a-32-4). Examples of the tetracarboxylic acid dianhydride include aromatic tetracarboxylic acid dianhydrides such as 4,4 ' - (hexafluoroisopropylidene) phthalic anhydride, 3,3 ', 4,4 ' -diphenylsulfone tetracarboxylic acid dianhydride, 3,3 ', 4,4 ' -benzophenone tetracarboxylic acid dianhydride, 2 ', 3,3 ' -benzophenone tetracarboxylic acid dianhydride, and a compound represented by the following formula (a-32-5); and aliphatic tetracarboxylic acid dianhydrides such as 1,2,3, 4-butanetetracarboxylic acid dianhydride. Among these, aromatic tetracarboxylic dianhydrides are preferred.

The tetracarboxylic dianhydride (a-32) may be 1 type alone or 2 or more types in combination.

The ratio of the constituent unit (A-32-1) to the constituent unit (A-32-4) in the constituent unit (A-32) is preferably 45 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 of the ratio is not particularly limited, i.e., 100 mol%. The constituent unit (A-32) may include at least 1 selected from the constituent unit (A-32-1) to the constituent unit (A-32-4), and may be formed of only 1 selected from the constituent unit (A-32-1) to the constituent unit (A-32-4).

When the constituent unit (a-32) contains 2 or more species of constituent units selected from the constituent unit (a-32-1) to the constituent unit (a-32-4), the ratio of the constituent units in the constituent unit (a-32) is not particularly limited, and may be any ratio.

The molar ratio [ (A-31)/(A-32) ] of the constituent unit (A-31) to the constituent unit (A-32) in the constituent unit A3 is preferably 10/90 to 90/10, more preferably 30/70 to 85/15, and still more preferably 50/50 to 80/20.

The proportion of the constituent unit derived from an aromatic tetracarboxylic dianhydride in the constituent unit (a-32) is preferably 45 mol% or more, more preferably 60 mol% or more, and still more preferably 85 mol% or more. The upper limit of the total content is not particularly limited, i.e., 100 mol%.

< constituent Unit B3>

Constituent unit B3 is a constituent unit derived from diamine in the copolymer of the present invention, and contains constituent unit (B-31) derived from a compound represented by the following formula (B-31). By including the constituent unit (B-31) in the constituent unit B, the transparency is excellent and the characteristics of low residual stress and low retardation can be achieved at the same time.

The compound represented by the formula (b-31) is the same as the compound represented by the formula (b-13-1).

The constituent unit B3 preferably further contains a constituent unit (B-32) derived from a compound represented by the following general formula (B-32). By including the constituent unit (B-32) in the constituent unit B3, the residual stress is reduced.

In the formula (b-32), Z¹And Z²Each independently represents a 2-valent aliphatic group or a 2-valent aromatic group, R¹And R²Each independently represents a 1-valent aromatic group or a 1-valent aliphatic group, R³And R⁴Each independently represents a 1-valent aliphatic group, R⁵And R⁶Each independently represents a 1-valent aliphatic group or a 1-valent aromatic group, m and n each independently represent an integer of 1 or more, and the sum of m and n represents an integer of 2 to 1000. Wherein R is¹And R²At least one of (a) and (b) represents a 1-valent aromatic group.

In the formula (b-32), 2 or more different repeating units represented in parallel by [ ] may be repeated in any form and order of random, alternating, or block.

In the formula (b-32), Z¹And Z²The 2-valent aliphatic group or the 2-valent aromatic group in (1) may be substituted with a fluorine atom. The aliphatic group having a valence of 2 includes saturated or unsaturated aliphatic groups having a valence of 2 and having 1 to 20 carbon atoms. The number of carbon atoms of the 2-valent aliphatic group is preferably 3 to 20.

Examples of the saturated aliphatic group having a valence of 2 include alkylene groups having 1 to 20 carbon atoms, and examples thereof include methylene, ethylene, propylene, trimethylene, tetramethylene, hexamethylene, octamethylene, decamethylene, and dodecamethylene.

Examples of the unsaturated aliphatic group having a valence of 2 include alkylene groups having 2 to 20 carbon atoms, for example, an ethenylene group, an propenylene group, and an alkylene group having an unsaturated double bond at a terminal.

Examples of the aromatic group having a valence of 2 include an arylene group having 6 to 20 carbon atoms and an aralkylene group having 7 to 20 carbon atoms. As Z¹And Z²In (3), specific examples of the arylene group having 6 to 20 carbon atoms may includeExamples thereof include o-phenylene, m-phenylene, p-phenylene, 4' -biphenylene, and 2, 6-naphthylene.

As Z¹And Z²Particularly preferred are trimethylene group and p-phenylene group, and more preferred is trimethylene group.

In the formula (b-32), as R¹～R⁶Examples of the 1-valent aliphatic group in (1) include 1-valent saturated or unsaturated aliphatic groups. Examples of the saturated aliphatic group having a valence of 1 include alkyl groups having 1 to 22 carbon atoms, and examples thereof include methyl, ethyl, and propyl groups. The 1-valent unsaturated aliphatic group includes alkenyl groups having 2 to 22 carbon atoms, and examples thereof include vinyl groups and propenyl groups. These groups may be substituted with fluorine atoms.

R as formula (b-32)¹、R²、R⁵And R⁶Examples of the aromatic group having a valence of 1 in (A) include aryl groups having 6 to 20 carbon atoms, aryl groups having 7 to 30 carbon atoms and substituted with alkyl groups, and aralkyl groups having 7 to 30 carbon atoms. The aromatic group having a valence of 1 is preferably an aryl group, more preferably a phenyl group.

R¹And R²At least one of them represents a 1-valent aromatic group, preferably R¹And R²Aromatic groups each having a valence of 1, more preferably R¹And R²Are all phenyl groups.

As R³And R⁴The alkyl group having 1 to 6 carbon atoms is preferable, and the methyl group is more preferable.

As R⁵And R⁶The aliphatic group having a valence of 1 is preferable, and the methyl group is more preferable.

In the formula (b-32), m represents the number of repeating siloxane units bonded to at least 1 aromatic group having a valence of 1, and n represents the number of repeating siloxane units bonded to an aliphatic group having a valence of 1.

m and n each independently represent an integer of 1 or more, and the sum (m + n) of m and n represents an integer of 2 to 1000. The sum of m and n is preferably an integer of 3 to 500, more preferably an integer of 3 to 100, and further preferably an integer of 3 to 50.

The ratio of m/n is preferably 50/50 to 99/1, more preferably 60/40 to 90/10, and still more preferably 70/30 to 80/20.

The equivalent weight of the functional group of the compound represented by the formula (b-32) is preferably 150 to 5,000g/mol, more preferably 400 to 4,000g/mol, and further preferably 500 to 3,000 g/mol.

The functional group equivalent means the mass of the compound represented by the formula (b-32) in which 1 mole of the functional group is averaged.

The content of the polyorganosiloxane unit is preferably 5 to 45% by mass, more preferably 7 to 40% by mass, and still more preferably 10 to 35% by mass, based on the total of the constituent unit A3 and the constituent unit B3. When the content of the polyorganosiloxane unit is within the above range, a low retardation and a low residual stress can be more highly satisfied.

The content of the polyorganosiloxane unit relative to the total of the constituent unit A3 and the constituent unit B3 is calculated from the mass ratio of the amount of the compound providing the constituent unit (B-32), preferably the compound represented by the formula (B-32), to the total amount of the raw materials providing the constituent unit A3 and the constituent unit B3.

As commercially available compounds of the compound represented by the formula (B-32), X-22-9409 and X-22-1660B-3, available from shin-Etsu chemical Co., Ltd.

The constituent unit B3 preferably further contains a constituent unit (B-33) derived from a compound represented by the following formula (B-33).

The compound represented by the formula (b-33) is the same as the compound represented by the formula (b-13-2) described above, and the preferred ranges are the same.

The copolymer of the present invention contains the above-mentioned constituent unit (B-33), and thus has improved transparency and heat resistance.

The proportion of the constituent unit (B-31) in the constituent unit B3 is preferably 45 mol% or more, more preferably 48 mol% or more, further preferably 85 mol% or more, further preferably 88 mol% or more, preferably 100 mol% or less, more preferably 99.5 mol% or less, further preferably 99.0 mol% or less. The constituent unit B3 may be formed of only the constituent unit (B-31).

When the constituent unit B3 includes the constituent unit (B-32), the ratio of the constituent unit (B-32) in the constituent unit B3 is preferably 0.01 to 15.0 mol%, more preferably 0.5 to 12.0 mol%, and still more preferably 1.0 to 8.0 mol%.

When the constituent unit B3 includes the constituent unit (B-33), the ratio of the constituent unit (B-3) in the constituent unit B3 is preferably 5 mol% or more, more preferably 10 mol% or more, further preferably 25 mol% or more, and is preferably 65 mol% or less, more preferably 55 mol% or less, further preferably 50 mol% or less, from the viewpoint of low residual stress.

When the constituent unit B3 includes the constituent unit (B-33), the total ratio of the constituent units (B-31) and (B-33) in the constituent unit B3 is preferably 85.0 to 100 mol%, more preferably 88.0 to 99.5 mol%, and still more preferably 92.0 to 99.0 mol%. When the constituent unit B3 does not include the constituent unit (B-33), the ratio of the constituent unit (B-31) in the constituent unit B3 is preferably in the same range as described above.

The content ratio of the total of the constituent units (B-31) to (B-33) in the constituent unit B3 is preferably 45 to 100 mol%, more preferably 60 to 100 mol%, still more preferably 85 to 100 mol%, and particularly preferably 100 mol%.

Constituent unit B3 may contain constituent units other than constituent units (B-31) to (B-33).

The diamine providing such a constituent unit is not particularly limited, and examples thereof include 1, 4-phenylenediamine, p-xylylenediamine, 3, 5-diaminobenzoic acid, 1, 5-diaminonaphthalene, 2 '-dimethylbiphenyl-4, 4' -diamine, 2 '-bis (trifluoromethyl) benzidine, 2' -dimethylbiphenyl-4, 4 '-diamine, 4' -diaminodiphenyl ether, 4 '-diaminodiphenylmethane, 1, 4-bis [2- (4-aminophenyl) -2-propyl ] benzene, 2-bis (4-aminophenyl) hexafluoropropane, 4' -diaminodiphenyl sulfone, 4 '-bisanilide, 3, 4' -diaminodiphenyl ether, aminobenzene, and the like, Aromatic diamines such as 1- (4-aminophenyl) -2, 3-dihydro-1, 3, 3-trimethyl-1H-indene-5-amine, α ' -bis (4-aminophenyl) -1, 4-diisopropylbenzene, N ' -bis (4-aminophenyl) terephthalamide, 4 ' -bis (4-aminophenoxy) biphenyl, 2-bis [4- (4-aminophenoxy) phenyl ] propane, 2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane and 1, 4-bis (4-aminophenoxy) benzene; alicyclic diamines such as 1, 3-bis (aminomethyl) cyclohexane and 1, 4-bis (aminomethyl) cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.

Constituent units other than constituent units (B-31) to (B-33) optionally contained in constituent unit B3 may be 1 type, or 2 or more types.

Constituent unit B3 preferably does not contain constituent units other than constituent units (B-31) to (B-33). In particular, from the viewpoint of achieving a low retardation, it is preferable that the constituent unit B3 does not contain a constituent unit derived from 2, 2' -bis (trifluoromethyl) benzidine.

< imide repeating structural Unit/amic acid repeating structural Unit >

The copolymer 3 has an imide repeating structural unit formed of a compound providing the constituent unit (A-31) and a compound providing the constituent unit (B-31), and an amic acid repeating structural unit formed of a compound providing the constituent unit (A-32) and a compound providing the constituent unit B3.

The copolymer 3 may also have an imide repeating structural unit formed of a compound other than the compound providing the constituent unit (A-31) and a compound providing the constituent unit B3, an imide repeating structural unit formed of a compound providing the constituent unit (A-31) and a compound other than the compound providing the constituent unit (B-31). Likewise, the copolymer 3 may also have an amic acid repeating structural unit formed from a compound other than the compound providing the constituent unit (A-32) and a compound providing the constituent unit B3.

[ method for producing copolymer 3]

The copolymer 3 can be produced by reacting a tetracarboxylic acid component composed of a compound providing the constituent unit (a-31) and a compound providing the constituent unit (a-32) with a diamine component containing a compound providing the constituent unit B3 including the constituent unit (B-31), and is preferably produced by a method having the following steps 1 and 2.

Step 1: a step of reacting the compound providing the constituent unit (A-31) with the compound providing the constituent unit (B-31) to obtain an oligomer having an imide repeating structural unit

And a step 2: a step of reacting the oligomer obtained in the step 1 with a compound that provides a constituent unit (A-32) and a compound that provides a constituent unit B3 to obtain a copolymer 3 having an imide repeating structural unit and an amic acid repeating structural unit

By the production method including the steps 1 and 2, the copolymer 3 capable of forming a film excellent in colorless transparency and heat resistance, and also excellent in low retardation and low residual stress can be produced.

The method for producing the copolymer 3 will be described below.

< tetracarboxylic acid component >

Examples of the compound that provides the constituent unit (A-31) include alicyclic tetracarboxylic dianhydrides (a-31), but the compound is not limited thereto, and derivatives thereof may be used as long as the same constituent unit is provided. Examples of the derivative include an alicyclic tetracarboxylic acid corresponding to the alicyclic tetracarboxylic dianhydride (a-31) and an alkyl ester of the alicyclic tetracarboxylic acid. As the compound providing the constituent unit (A-31), alicyclic tetracarboxylic dianhydride (a-31) is preferred.

Similarly, the compound providing the constituent unit (A-32) may be a tetracarboxylic dianhydride (a-32), but is not limited thereto, and may be a derivative thereof insofar as the same constituent unit is provided. Examples of the derivative include a tetracarboxylic acid corresponding to the tetracarboxylic dianhydride (a-32) and an alkyl ester of the tetracarboxylic acid. As the compound providing the constituent unit (A-32), tetracarboxylic dianhydride (a-32) is preferred.

The molar ratio [ (A-31)/(A-32) ] of the compound which provides the constituent unit (A-31) to the compound which provides the constituent unit (A-32) in the tetracarboxylic acid component is preferably 10/90 to 90/10, more preferably 30/70 to 85/15, and still more preferably 50/50 to 80/20.

As the compound which provides the constituent unit (A-31), a compound which provides the constituent unit (A-31-1) is preferable. The proportion of the compound that provides the constituent unit (A-31-1) among the compounds that provide the constituent unit (A-31) is preferably 45 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 of the ratio is not particularly limited, i.e., 100 mol%.

As the compound that provides the constituent unit (A-32), 1 or more selected from the group consisting of a compound that provides the constituent unit (A-32-1), a compound that provides the constituent unit (A-32-2), a compound that provides the constituent unit (A-32-3), and a compound that provides the constituent unit (A-32-4) are preferable. The ratio of the total of the compounds providing the constituent unit (a-32-1) to the constituent unit (a-32-4) in the compounds providing the constituent unit (a-32) is preferably 45 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 of the ratio is not particularly limited, i.e., 100 mol%.

The tetracarboxylic acid component may contain a compound other than the compounds that provide the constituent unit (A-31-1), the constituent unit (A-32-2), the constituent unit (A-32-3), and the constituent unit (A-32-4), and the number of the compounds may be 1 or 2 or more.

< diamine component >

Examples of the compound that can provide the constituent unit B3 include diamines, but are not limited thereto, and derivatives thereof may be provided as long as the same constituent unit is provided. Examples of the derivative include diisocyanates corresponding to diamines. As the compound providing the constituent unit B3, a diamine is preferable.

As the compound providing the constituent unit (B-31), a compound represented by the formula (B-31) (i.e., diamine) is preferable. Similarly, as the compound which provides the constituent unit (B-32), a compound represented by the general formula (B-32) (i.e., diamine) is preferable, and as the compound which provides the constituent unit (B-33), a compound represented by the formula (B-33) (i.e., diamine) is preferable.

The diamine component contains the compound that provides the constituent unit (B-31) preferably at least 45 mol%, more preferably at least 48 mol%, even more preferably at least 85 mol%, even more preferably at least 88 mol%, and preferably at most 100 mol%, even more preferably at most 99.5 mol%, even more preferably at most 99.0 mol%. The diamine component may be formed only from the compound that provides the constituent unit (B-31).

When the compound that provides the constituent unit (B-32) is contained as the diamine component, the compound that provides the constituent unit (B-32) is contained in the total diamine component by preferably 0.01 to 15.0 mol%, more preferably 0.5 to 12.0 mol%, and further preferably 1.0 to 8.0 mol%.

When the compound that provides the constituent unit (B-33) is contained as the diamine component, the compound that provides the constituent unit (B-33) is contained in the total diamine component by preferably 5 to 65 mol%, more preferably 10 to 55 mol%, and still more preferably 25 to 50 mol%.

The diamine component may be formed from a combination of 1 or more selected from the group consisting of a compound that provides the constituent unit (B-31), a compound that provides the constituent unit (B-32), and a compound that provides the constituent unit (B-33).

The total content ratio of the compound that provides the constituent unit (B-31), the compound that provides the constituent unit (B-32), and the compound that provides the constituent unit (B-33) is preferably 45 mol% or more, more preferably 60 mol% or more, and still more preferably 85 mol% or more, of the total diamine components. The upper limit of the total content is not particularly limited, i.e., 100 mol%.

The diamine component may contain a compound that provides the constituent unit B3 in addition to the compound that provides the constituent unit (B-31), the compound that provides the constituent unit (B-32), and the compound that provides the constituent unit (B-33), and such compounds include the above-mentioned aromatic diamine, alicyclic diamine, and aliphatic diamine, and derivatives thereof (e.g., diisocyanate).

The diamine component may optionally contain 1 or 2 or more compounds other than the compounds providing the constituent units (B-31) to (B-33).

The amount ratio of the tetracarboxylic acid component to the diamine component to be used for producing the copolymer 3 is preferably 0.9 to 1.1 mol of the diamine component relative to 1 mol of the tetracarboxylic acid component.

< solvent >

The solvent used for producing the copolymer 3 may be any solvent capable of dissolving the produced copolymer. Specific examples of the reaction solvent are described with respect to the polyimide resin 1. Among the above reaction solvents, an amide solvent or a lactone solvent is preferable, an amide solvent is more preferable, and N-methyl-2-pyrrolidone is further preferable. The reaction solvent can be used alone or in combination of 2 or more.

< step 1>

Step 1 is a step of reacting a compound that provides the constituent unit (A-31) with a compound that provides the constituent unit (B-31) to obtain an oligomer having an imide repeating structural unit.

When the tetracarboxylic acid component used in step 1 contains a compound that provides the constituent unit (A-31) and the constituent unit (A-31) contains the constituent unit (A-31-1), the compound that provides the constituent unit (A-31-1) is preferably used in the whole amount in step 1.

The diamine component used in step 1 may contain a compound that provides the constituent unit (B-31), and may contain a diamine component other than the compound that provides the constituent unit (B-31) within a range that does not impair the effects of the present invention. Examples of such a compound include compounds that provide the constituent unit (B-33).

The amount of the diamine component used in step 1 is preferably 0.9 to 1.1 mol, more preferably 1.0 to 1.1 mol, based on the compound providing the constituent unit (A-31).

The method for reacting the tetracarboxylic acid component containing the compound providing the constituent unit (a-31) and the diamine component containing the compound providing the constituent unit (B-31) to obtain the oligomer in the step 1 is not particularly limited, and a known method can be used. The specific reaction method is as described for the polyimide resin 1.

The oligomer obtained in step 1 has an imide repeating structural unit formed of a compound that provides a constituent unit (A-31) and a compound that provides a constituent unit (B-31).

The oligomer obtained in step 1 preferably has amino groups at both ends of the main chain of the molecular chain.

By the above method, a solution containing the oligomer dissolved in the solvent is obtained. The solution containing the oligomer obtained in step 1 may contain at least a part of the components used as the tetracarboxylic acid component and the diamine component in step 1 as unreacted monomers within a range not to impair the effects of the present invention.

< step 2>

Step 2 is a step of reacting the oligomer obtained in step 1 with a compound that provides the constituent unit (a-32) and a compound that provides the constituent unit B3 to obtain a copolymer having an imide repeating structural unit and an amic acid repeating structural unit.

The tetracarboxylic acid component used in step 2 contains a compound that provides the constituent unit (a-32), and may contain a compound that provides the constituent unit (a-31) within a range that does not impair the effects of the present invention. Among these, the tetracarboxylic acid component used in step 2 preferably does not contain a compound that provides the constituent unit (A-31-1). Further, the compound providing the constituent unit (A-32) is preferably used in the whole amount in the step 2.

The diamine component used in step 2 is a compound that provides the constituent unit B3. The diamine component used in step 2 is a component other than the diamine component constituting the oligomer obtained in step 1, of the compound providing the constituent unit B3 in the raw material monomers in the copolymer of the present invention. The unreacted diamine component remaining in the oligomer-containing solution obtained in step 1 can be used as the diamine component in step 2. The diamine component used in step 2 preferably contains at least a compound that provides the constituent unit (B-31). When the compound providing the constituent unit (B-32) is used, it is preferable to use the whole amount thereof in the step 2.

The method for reacting the tetracarboxylic acid component containing the compound providing the constituent unit (a-32) and the diamine component containing the compound providing the constituent unit B3 for obtaining the copolymer in the step 2 with the oligomer obtained in the step 1 is not particularly limited, and a known method can be used.

Specific reaction methods include: (1) a method of charging the oligomer, the tetracarboxylic acid component, the diamine component, and the solvent obtained in the step 1 into a reactor, and stirring them at 0 to 120 ℃, preferably 5 to 80 ℃ for 1 to 72 hours; (2) a method in which the oligomer obtained in step 1, a diamine component, preferably a diamine component other than the compound providing the constituent unit (B-32), and a solvent are charged into a reactor and dissolved, then a tetracarboxylic acid component is charged and stirred at 0 to 120 ℃, preferably 5 to 80 ℃ for 1 to 72 hours, and then the compound providing the constituent unit (B-32) and the solvent are charged as the diamine component and stirred at 0 to 120 ℃, preferably 15 to 80 ℃ for 0.5 to 10 hours. When the diamine component contains a compound that provides the constituent unit (B-32), the production method (2) is preferable among the above.

When the reaction is carried out at 80 ℃ or lower, the molecular weight of the copolymer obtained in step 2 does not vary depending on the temperature history at the time of polymerization, and the progress of thermal imidization can be suppressed, so that the copolymer can be stably produced.

The copolymer 3 is a copolymer having an amic acid repeating structural unit and an imide repeating structural unit, and is a product of addition polymerization of the tetracarboxylic acid component in the step 2, the diamine component in the step 2, and the oligomer obtained in the step 1.

The copolymer 3 has an imide repeating structural unit formed of a compound providing the structural unit (a-31) and a compound providing the structural unit (B-31) in step 1, and has an amic acid repeating structural unit formed of a compound providing the structural unit (a-32) and a compound providing the structural unit B3 in step 2.

By the above method, a copolymer solution containing the copolymer 3 dissolved in the solvent was obtained.

The concentration of the copolymer in the obtained copolymer solution is usually in the range of 1 to 50% by mass, preferably 3 to 35% by mass, and more preferably 10 to 30% by mass.

The number average molecular weight of the copolymer 3 is preferably 5,000 to 500,000 from the viewpoint of mechanical strength of the polyimide film to be obtained. The number average molecular weight of the copolymer 3 can be determined, for example, from a standard polymethyl methacrylate (PMMA) conversion value measured by gel permeation chromatography.

[ method for producing polyimide film ]

The method for producing the polyimide film of the present invention is not particularly limited, and a known method can be used. For example, a method of applying a polyimide varnish onto a smooth support such as a glass plate, a metal plate, or a plastic, or forming the polyimide varnish into a film, and then removing an organic solvent such as a reaction solvent or a diluting solvent contained in the varnish by heating may be mentioned.

Examples of the method for applying the varnish include known coating methods such as spin coating, slit coating, and blade coating. Among them, slit coating is preferable from the viewpoint of controlling intermolecular orientation, improving chemical resistance, and handling.

The organic solvent contained in the varnish is preferably removed by heating, and the varnish is preferably dried at a temperature not lower than 150 ℃ at a temperature not higher than the boiling point of the organic solvent used (not particularly limited, preferably 200 to 500 ℃). Further, it is preferable to perform drying under an air atmosphere or a nitrogen atmosphere. The pressure of the drying atmosphere may be reduced pressure, normal pressure or increased pressure.

< polyimide varnish >

The polyimide varnish is obtained by dissolving a polyimide resin in an organic solvent. That is, the polyimide varnish includes a polyimide resin and an organic solvent, and the polyimide resin is dissolved in the organic solvent.

The organic solvent is not particularly limited as long as the polyimide resin is dissolved, and it is preferable to use 2 or more of the above-described compounds alone or in combination as a reaction solvent used for producing the polyimide resin.

The polyimide varnish may be a polyimide solution itself obtained by dissolving a polyimide resin obtained by a polymerization method in a reaction solvent, or may be a polyimide solution obtained by further adding a diluting solvent to the polyimide solution.

The polyimide resins 1 and 2 have solvent solubility, and therefore can be used as stable varnish having a high concentration at room temperature. The polyimide varnish preferably contains 5 to 40 mass%, more preferably 10 to 30 mass% of the polyimide resin 1 or 2. The viscosity of the polyimide varnish is preferably 1 to 200 pas, more preferably 1.5 to 100 pas, and still more preferably 2 to 100 pas. The viscosity of the polyimide varnish was measured at 25 ℃ using an E-type viscometer.

The polyimide varnish may contain various additives such as inorganic fillers, adhesion promoters, release agents, flame retardants, ultraviolet stabilizers, surfactants, leveling agents, defoaming agents, fluorescent whitening agents, crosslinking agents, polymerization initiators, and photosensitizers, as long as the required properties of the polyimide film are not impaired.

The method for producing the polyimide varnish is not particularly limited, and a known method can be applied.

< Polyamic acid varnish >

The polyimide film may be produced using a polyamic acid varnish obtained by dissolving a polyamic acid in an organic solvent.

The polyamic acid contained in the polyamic acid varnish is preferably a precursor of the polyimide resin 1 or 2. The polyamic acid as a precursor of the polyimide resin 1 is: a product of addition polymerization of a tetracarboxylic acid component comprising the compound providing the constituent unit (A-11) and the compound providing the constituent unit (A-12) with a diamine component comprising the compound providing the constituent unit (B-11) and the compound providing the constituent unit (B-12). The polyamic acid as a precursor of the polyimide resin 2 is: a product of addition polymerization of a tetracarboxylic acid component comprising the compound providing the constituent unit (A-21) and the compound providing the constituent unit (A-22) with a diamine component comprising 70 mol% or more of the compound providing the constituent unit (B-21). By imidizing (dehydrating ring closure) these polyamic acids, a polyimide resin 1 or 2 as a final product is obtained.

As the organic solvent contained in the polyamic acid varnish, an organic solvent contained in a polyimide varnish may be used.

In the present invention, the polyamic acid varnish may be a polyamic acid solution itself obtained by addition polymerization of a tetracarboxylic acid component and a diamine component in a reaction solvent, or may be a polyamic acid solution to which a diluting solvent is further added.

The method for producing the polyimide film using the polyamic acid varnish is not particularly limited, and a known method can be used. For example, a polyamic acid varnish may be applied to a smooth support such as a glass plate, a metal plate, or a plastic or formed in a film form, an organic solvent such as a reaction solvent or a diluting solvent contained in the varnish may be removed by heating to obtain a polyamic acid film, and the polyamic acid in the polyamic acid film may be 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 ℃. The heating temperature for imidizing the polyamic acid by heating is preferably 200 to 400 ℃.

The method of imidization is not limited to thermal imidization, and chemical imidization may be applied.

< copolymer varnish >

The polyimide film may be produced using a copolymer varnish in which the above-mentioned copolymer 3 is dissolved in an organic solvent.

The copolymer varnish is obtained by dissolving a copolymer 3, which is a precursor of a polyimide resin, in an organic solvent. That is, the copolymer varnish contains the copolymer 3 and an organic solvent, and the copolymer 3 is dissolved in the organic solvent.

The organic solvent is not particularly limited as long as the copolymer 3 is dissolved, and 2 or more kinds of the above-mentioned compounds are preferably used alone or in combination as a solvent for producing the copolymer 3.

The copolymer varnish may be the copolymer solution itself, or may be one obtained by further adding a diluting solvent to the copolymer solution.

The copolymer varnish may further contain an imidization catalyst and a dehydration catalyst in order to efficiently perform imidization of the amic acid sites in the copolymer 3. The imidization catalyst may be any imidization catalyst having a boiling point of 40 ℃ or higher and 180 ℃ or lower, and an amine compound having a boiling point of 180 ℃ or lower may be preferably used. When the imidization catalyst has a boiling point of 180 ℃ or lower, there is no fear that the film is colored and the appearance is deteriorated when the film is dried at a high temperature after the film is formed. In addition, in the case of an imidization catalyst having a boiling point of 40 ℃ or higher, the possibility of volatilization before sufficient imidization can be avoided.

As the amine compound suitably used as the imidization catalyst, pyridine or picoline is exemplified. The imidization catalyst can be used singly or in combination of 2 or more.

Examples of the dehydration catalyst include anhydrides such as acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, and trifluoroacetic anhydride; carbodiimide compounds such as dicyclohexylcarbodiimide; and the like. These may be used alone or in combination of 2 or more.

The copolymer 3 contained in the copolymer varnish has solvent solubility, and thus a varnish having a high concentration can be prepared. The copolymer varnish preferably contains 5 to 40 mass%, more preferably 10 to 30 mass% of the copolymer 3. The viscosity of the copolymer varnish is preferably 0.1 to 100 pas, more preferably 0.1 to 20 pas. The viscosity of the copolymer varnish was measured at 25 ℃ using an E-type viscometer.

The copolymer varnish may contain various additives such as an inorganic filler, an adhesion promoter, a release agent, a flame retardant, an ultraviolet stabilizer, a surfactant, a leveling agent, an antifoaming agent, a fluorescent whitening agent, a crosslinking agent, a polymerization initiator, and a photosensitizer, within a range not to impair the required characteristics of the polyimide film.

The method for producing the varnish is not particularly limited, and a known method can be applied.

The heating temperature for drying the copolymer varnish to obtain a copolymer film is preferably 50 to 150 ℃. The heating temperature for imidizing the copolymer 3 by heating may be selected from the range of preferably 200 to 500 ℃, more preferably 250 to 450 ℃, and still more preferably 300 to 400 ℃. The heating time is usually 1 minute to 6 hours, preferably 5 minutes to 2 hours, and more preferably 15 minutes to 1 hour.

Examples of the heating atmosphere include air gas, nitrogen gas, oxygen gas, hydrogen gas, and nitrogen/hydrogen mixed gas, and nitrogen gas having an oxygen concentration of 100ppm or less and nitrogen/hydrogen mixed gas having a hydrogen concentration of 0.5% or less are preferable in order to suppress coloration of the polyimide resin to be obtained.

[ adjustment of moisture content of polyimide film ]

The polyimide film has a moisture content of 1,000 to 35,000 mass ppm. The method for adjusting the moisture content of the polyimide film to be within the above range is not particularly limited, and the polyimide film may be produced by adding moisture to a polyimide varnish applied on a glass substrate or a silicon substrate, but it is more preferable to absorb moisture after the polyimide film is produced. Further, after the polyimide film is formed, a metal film or an oxide semiconductor film may be stacked on the polyimide film, and moisture may be absorbed after various electronic devices are manufactured.

When the polyimide film is made to absorb moisture, it is preferably kept for a predetermined time in a temperature and humidity environment at a temperature of preferably 10 to 40 ℃, more preferably 15 to 35 ℃, and a humidity of preferably 40 to 80% RH, more preferably 50 to 70% RH, and particularly preferably 55 to 65% RH. The holding time is also affected by the temperature and humidity, and is preferably 20 hours or more, more preferably 40 hours or more, further preferably 60 hours or more, and usually 170 hours or less. RH represents relative humidity.

(Metal film or oxide semiconductor film)

In the laminate of the present invention, a metal film or an oxide semiconductor film is further laminated on the polyimide film. By laminating a metal film or an oxide semiconductor film on a polyimide film, a target electronic device (conductive film) such as a touch sensor or an OLED can be formed on the polyimide film.

Preferable specific examples of the metal film include a copper mesh and a silver mesh.

As a preferable specific example of the oxide semiconductor film, at least 1 selected from the group consisting of Indium Tin Oxide (ITO), amorphous silicon, Indium Gallium Zinc Oxide (IGZO), and Low Temperature Polysilicon (LTPS) can be cited.

Further, another metal film or an oxide semiconductor film may be stacked over the metal film or the oxide semiconductor film.

The thickness of the metal film or the oxide semiconductor film is 1 to 400nm, preferably 10 to 300nm, and more preferably 20 to 200nm, from the viewpoint of manufacturing an electronic device on a polyimide film.

The method for laminating a metal film or an oxide semiconductor film on a polyimide film is not particularly limited, and a physical vapor deposition method or a chemical vapor deposition method is preferable. Examples of the physical vapor deposition method include a vacuum vapor deposition method, a sputtering method, and an ion plating method, and examples of the chemical vapor deposition method include a plasma chemical vapor deposition method, a thermochemical vapor deposition method, and a photochemical vapor deposition method.

The conductive thin film is obtained by peeling and removing a glass substrate or a silicon substrate from a laminate in which a metal film or an oxide semiconductor film is laminated. That is, the method for producing a conductive thin film of the present invention includes a step of peeling and removing the glass substrate or the silicon substrate from the laminate.

The conductive thin film may be obtained by peeling off a glass substrate or a silicon substrate immediately after a metal film or an oxide semiconductor film is laminated on a polyimide thin film to produce a conductive thin film, or may be obtained by peeling off a glass substrate or a silicon substrate as needed while keeping a laminate. Storage in the state of a laminate is preferable because handling property at the time of conveyance of the conductive thin film is improved.

The method for peeling and removing the glass substrate or the silicon substrate from the laminate is not particularly limited, and the laminate of the present invention can easily and stably peel the polyimide film from the glass substrate or the silicon substrate, and therefore can be mechanically peeled without being irradiated with a laser.

Examples

The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples in any way.

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

(1) Thickness of film

The film thickness was measured using a laser microscope (manufactured by KEYENCE CORPORATION).

(2) Glass transition temperature (Tg)

The residual stress was removed by heating up to a temperature sufficient for removing the residual stress in a tensile mode under conditions of a specimen size of 2mm × 20mm, a load of 0.1N, and a heating rate of 10 ℃/min using a thermomechanical analyzer "TMA/SS 6100" (manufactured by Hitachi High-Tech Science Corporation), followed by cooling to room temperature. Thereafter, the elongation of the test piece was measured under the same conditions as in the treatment for removing the residual stress, and the inflection point at which the elongation was observed was determined as the glass transition temperature.

(3) Total light transmittance, Yellow Index (YI)

For total light transmittance and YI, according to JIS K7105: 1981, measurement was carried out using a color/turbidity simultaneous measurement instrument "COH 400" (manufactured by Nippon Denshoku industries Co., Ltd.).

(4) Thickness retardation (Rth)

The thickness retardation (Rth) was measured using an ellipsometer "M-220" (manufactured by Nippon spectral Co., Ltd.). The value of the thickness retardation at a measurement wavelength of 590nm was measured. In addition, regarding Rth, when nx is a maximum value, ny is a minimum value, nz is a refractive index in a thickness direction, and d is a thickness of the film, the maximum value is a refractive index in a plane of the polyimide film, and the thickness is expressed by the following formula.

Rth＝[{(nx+ny)/2}-nz]×d

(5) Moisture content of polyimide film

The film was measured by Karl-Fischer method at 260 ℃ for 30 minutes. As the measuring machine, a micro-moisture measuring device "CA-200" (moisture meter of Mitsubishi Chemical Analyzech Co., Ltd., Karl-Fischer Co., Ltd.) and a moisture vaporizing device "VA-236S" (Mitsubishi Chemical Analyzech Co., Ltd., with a sample converter) were used.

(6) Peel strength

A90 DEG peel test was carried out in accordance with JIS K6854-1 to measure the peel strength at the interface between the polyimide film and the glass. For the peel strength, 5 measurements were made and the average value thereof was taken as the peel strength.

The tetracarboxylic acid component and the diamine component used in the production examples, other components, and their abbreviations are as follows.

< tetracarboxylic acid component >

HPMDA: 1,2,4, 5-Cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi gas chemical Co., Ltd.; Compounds represented by formulae (a-11) and (a-21))

ODPA: 4, 4' -oxydiphthalic anhydride (manufactured by Manac incorporated; compounds represented by the formulae (a-12) and (a-22))

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-31-1))

s-BPDA: 3,3 ', 4, 4' -Biphenyltetracarboxylic dianhydride (a compound represented by the formula (a-32-1s), manufactured by Mitsubishi chemical Co., Ltd.)

< diamine component >

3, 3' -DDS: 3, 3' -diaminodiphenyl sulfone (manufactured by Seika Corporation; compounds represented by the formulae (b-11) and (b-21))

BAPS: bis [4- (4-aminophenoxy) phenyl ] sulfone (manufactured by Seika Corporation; compound represented by formula (b-12))

HFBAPP: 2, 2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane (manufactured by Seika Corporation; compound represented by the formula (b-22-3))

6 FODA: 2,2 '-bis (trifluoromethyl) -4, 4' -diaminodiphenyl ether (ChinaTech (Tianjin) chemical Co., Ltd., product of Ltd., compound represented by the formula (b-31))

X-22-1660B-3: both terminal amino-modified silicone oils (Compound represented by the formula (b-32) (functional group equivalent: 2200g/mol or 2170g/mol, manufactured by shin Etsu chemical Co., Ltd.)

< others >

GBL: gamma-butyrolactone (manufactured by Mitsubishi chemical corporation)

TEA: triethylamine (manufactured by Kanto chemical Co., Ltd.)

NMP: n-methyl-2-pyrrolidone (manufactured by Mitsubishi chemical corporation)

Production example 1

A300 mL 5-neck round-bottomed flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a condenser tube, a dean-Stark, a thermometer, and a glass end cap was charged with 3, 3' -DDS 13.845g (0.056 mol), BAPS 24.115g (0.056 mol), and GBL 41.903g, and stirred at a rotation speed of 200rpm in a nitrogen atmosphere at a temperature of 70 ℃ in the system to obtain a solution.

To this solution were added HPMDA 22.499g (0.100 mol), ODPA 3.459g (0.011 mol) and GBL 12.804g in combination, and then TEA 0.564g as an imidization catalyst was charged and heated with a mantle heater to raise the temperature in the reaction system to 190 ℃ over about 20 minutes. The distilled components were collected, and the reaction mixture was refluxed for about 5 hours while adjusting the revolution rate in accordance with the increase in viscosity and maintaining the temperature in the reaction system at 190 ℃.

Then, GBL 175.981g was added so that the solid content concentration became 20 mass%, and after cooling the temperature in the reaction system to 100 ℃, the mixture was stirred and homogenized for about 1 hour to obtain a polyimide varnish 1.

Next, the obtained polyimide varnish 1 was applied onto a glass plate by spin coating, and held at 80 ℃ for 20 minutes on a hot plate, and then heated at 260 ℃ for 30 minutes in a hot air dryer under an air atmosphere to evaporate the solvent, thereby obtaining a film.

Production example 2

In a 300mL 5-neck round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a condenser tube, a dean-Stark bed, a thermometer, and a glass end cap, 3' -DDS 23.530g (0.094 mol), HFBAPP 12.247g (0.024 mol), and GBL 62.820g were charged, and the mixture was stirred at a temperature of 70 ℃ in the system and a rotation speed of 200rpm in a nitrogen atmosphere to obtain a solution.

To this solution were added HPMDA 21.158g (0.094 mol), ODPA 7.313g (0.024 mol) and GBL 15.705g in combination, and then TEA 0.596g as an imidization catalyst was charged and heated with a mantle heater to raise the temperature in the reaction system to 190 ℃ over about 20 minutes. The distilled components were collected, and the reaction mixture was refluxed for 5 hours while adjusting the revolution speed in accordance with the increase in viscosity and maintaining the temperature in the reaction system at 190 ℃.

Then, GBL 161.475g was added so that the solid content concentration became 20 mass%, and after cooling the temperature in the reaction system to 100 ℃, the mixture was stirred and homogenized for about 1 hour to obtain a polyimide varnish 2.

Next, the obtained polyimide varnish 2 was applied onto a glass plate by spin coating, and the resultant was held at 80 ℃ for 20 minutes on a hot plate, and then heated at 260 ℃ for 30 minutes in a hot air dryer under an air atmosphere to evaporate the solvent, thereby obtaining a film.

Production example 3

6FODA 26.953g (0.0802 mol) and NMP 56.000g were put into a 500mL 5-neck round-bottom flask equipped with a stainless steel semilunar stirring blade, a nitrogen inlet tube, a condenser tube, a dean-Stark bed, a thermometer, and a glass end cap, and stirred at a temperature of 70 ℃ in the system and a nitrogen atmosphere at a rotation speed of 200rpm to obtain a solution.

To this solution were added CpODA 19.231g (0.050 mol) and NMP 14.000g together, and then TEA 0.253g as an imidization catalyst was charged, and the mixture was heated with a mantle heater to raise the temperature in the reaction system to 190 ℃ over about 20 minutes. The distilled components were collected, and the reaction mixture was refluxed for 1 hour while adjusting the revolution speed in accordance with the increase in viscosity and maintaining the temperature in the reaction system at 190 ℃. Thereafter, 85.806g of NMP was added, and the temperature in the reaction system was cooled to 50 ℃ to obtain a solution containing an oligomer having an imide repeating structural unit.

To the resulting solution were added s-BPDA 9.814g (0.033 mol) and NMP 7.527g together, and the mixture was stirred at 50 ℃ for 5 hours. After 100.000g of NMP was added and homogenized, a mixed solution of 14.002g (0.003 mol) of X-22-1660B-3 dissolved in 16.667g of NMP was poured in the mixture and stirred for about 1 hour to obtain varnish 3 containing a copolymer (PI-B-PAA) having a solid content of about 20 mass%. The copolymer having an imide repeating structural unit and an amic acid repeating structural unit is referred to herein as "PI-b-PAA".

Subsequently, the varnish 3 obtained was applied onto a glass plate by spin coating, and the plate was held at 80 ℃ for 20 minutes on a hot plate, and heated at 350 ℃ for 30 minutes in a hot air dryer under an air atmosphere to evaporate the solvent, thereby obtaining a polyimide film.

The polyimide films obtained in production examples 1 to 3 were subjected to the above measurement. The results are shown in tables 1 and 2.

[ Table 1]

TABLE 1

[ Table 2]

TABLE 2

Examples 1 to 2 and comparative example 1

The polyimide varnish 1 obtained in production example 1 was coated on a glass plate by spin coating, and was held at 80 ℃ for 20 minutes on a hot plate, and then heated at 260 ℃ for 30 minutes in a hot air dryer under an air atmosphere to evaporate the solvent, thereby obtaining a 2-layer laminate (glass/polyimide film). Further, SiO was formed on the polyimide film of the laminate by sputtering to a thickness of 30nm₂Film and an ITO film having a thickness of 120nm was formed thereon to obtain a 4-layer laminate (glass/polyimide film/SiO)₂film/ITO film). The moisture content of the polyimide film in the 4-layer laminate was adjusted by maintaining the obtained 4-layer laminate under the conditions described in table 3.

Examples 3 to 4 and comparative example 2

The polyimide varnish 2 obtained in production example 2 was applied onto a glass plate by spin coating, and the plate was held at 80 ℃ for 20 minutes on a hot plate, and then heated at 260 ℃ for 30 minutes in a hot air dryer under an air atmosphere to evaporate the solvent, thereby obtaining a 2-layer laminate (glass/polyimide film). Further, SiO was formed on the polyimide film of the laminate by sputtering to a thickness of 30nm₂Film and an ITO film having a thickness of 120nm was formed thereon to obtain a 4-layer laminate (glass/polyimide film/SiO)₂film/ITO film). The moisture content of the polyimide film in the 4-layer laminate was adjusted by maintaining the obtained 4-layer laminate under the conditions described in table 3.

Examples 5 to 6

The varnish 3 obtained in production example 3 was applied onto a glass plate by spin coating, and the plate was held at 80 ℃ for 20 minutes on a hot plate, and then heated at 350 ℃ for 30 minutes in a hot air dryer under an air atmosphere to evaporate the solvent, thereby obtaining a 2-layer laminate (glass/polyimide film). Further, SiO was formed on the polyimide film of the laminate by sputtering to a thickness of 30nm₂Film and an ITO film having a thickness of 120nm was formed thereon to obtain a 4-layer laminate (glass/polyimide film/SiO)₂film/ITO film). The obtained 4-layer laminate was held under the conditions described in table 3, and the polyimide thickness in the 4-layer laminate was adjustedMoisture content of the film.

The laminate obtained above was subjected to the above peel test. The results are shown in Table 3.

In the laminate of comparative example 1, the film could not be peeled from the glass, and the peel strength could not be measured. In addition, in the laminate of comparative example 2, the thin film was broken when peeled from the glass, and the peel strength could not be measured.

[ Table 3]

TABLE 3

From the results in table 3, it is understood that the laminate of the present invention in which the moisture content of the polyimide film is adjusted to be within the predetermined range has relatively low peel strength, and the polyimide film can be easily and stably peeled from the glass substrate or the silicon substrate.

The results in tables 1 and 2 show that the polyimide films of production examples 1 to 3 are excellent in both colorless transparency and optical isotropy.

Claims

1. A laminate wherein a polyimide film is laminated on a glass substrate or a silicon substrate, and a metal film or an oxide semiconductor film is further laminated on the polyimide film, wherein the metal film or the oxide semiconductor film has a thickness of 1 to 400nm, and the polyimide film has a water content of 1000 to 35000 mass ppm.

2. The laminate according to claim 1, wherein the polyimide film has a peel strength from a glass substrate or a silicon substrate of 20gf/cm or less.

3. The laminate according to claim 1 or 2, wherein the polyimide film has a film thickness of 3 to 20 μm.

4. The laminate according to any one of claims 1 to 3, wherein the oxide semiconductor film is at least 1 selected from the group consisting of indium tin oxide, amorphous silicon, indium gallium zinc oxide, and low-temperature polysilicon.

5. A conductive thin film obtained by peeling and removing the glass substrate or the silicon substrate from the laminate according to any one of claims 1 to 4.

6. A method for manufacturing a conductive thin film, comprising:

adjusting the water content of the polyimide film to 1000-35000 mass ppm;

7. The method for producing a conductive film according to claim 6, wherein the step of adjusting the water content of the polyimide film is a step of holding the polyimide film in a temperature-humidity environment of 10 to 40 ℃ and 40 to 80% RH for 20 hours or longer.

8. The method of manufacturing a conductive thin film according to claim 6 or 7, wherein a physical vapor deposition method or a chemical vapor deposition method is used in the step of laminating a metal film or an oxide semiconductor film on the polyimide film.