WO2018079707A1

WO2018079707A1 - Polyimide and flexible device using same

Info

Publication number: WO2018079707A1
Application number: PCT/JP2017/038882
Authority: WO
Inventors: 知則中山; 則男三浦; 幸徳小濱; 久野　信治
Original assignee: 宇部興産株式会社
Priority date: 2016-10-27
Filing date: 2017-10-27
Publication date: 2018-05-03
Also published as: TW201819471A; JP7215904B2; JPWO2018079707A1; KR20190077015A; CN109923148A

Abstract

The present invention relates to a polyimide which is obtained from a tetracarboxylic acid component and a diamine component, and which is configured such that: a film thereof having a thickness of 10 μm has a yellowness of less than 3 and a linear expansion coefficient from 50°C to 200°C of 55 ppm/K or less; and a film thereof having a thickness of 10 μm has a light transmittance of 70% or more at a wavelength of 365 nm and a light transmittance of less than 0.1% at a wavelength of 308 nm.

Description

Polyimide and flexible device using the same

The present invention relates to a polyimide having excellent transparency and a flexible device using the same.

Conventionally, glass substrates have been used for electronic devices such as liquid crystal display elements and flat panel displays using organic EL display elements. However, when glass is made thin for weight reduction, the problem is that it becomes fragile due to insufficient strength. There is. Therefore, studies have been made to use resin materials that can be easily reduced in weight and thickness, for example, polyimide films as alternative materials for glass, and various polyimide films for substrates have been proposed (for example, Patent Documents 1 to 3). etc).

However, various characteristics are required for the substrate of the display device (display device), and further improvement of the proposed polyimide film has been desired.

JP 2007-231224 A International Publication No. 2013/179727 International Publication No. 2014/162733

The present invention is particularly suitably used as a substrate for a display device such as a liquid crystal display, an organic EL display, and electronic paper, and as a substrate for a light receiving device such as a light receiving element of a thin film solar cell, a touch sensor, or a touch panel. It is an object to provide a polyimide and a polyimide film that can be used.

The present invention relates to the following items.
1. A polyimide obtained from a tetracarboxylic acid component and a diamine component,
The yellowness in a film having a thickness of 10 μm is less than 3,
The linear expansion coefficient from 50 ° C. to 200 ° C. is 55 ppm / K or less,
A polyimide having a light transmittance of 70% or more at a wavelength of 365 nm and a light transmittance of less than 0.1% at a wavelength of 308 nm in a 10 μm thick film.
2. Item 2. The polyimide according to Item 1, wherein 90 mol% or more of the tetracarboxylic acid component is a compound having an alicyclic structure.
3. The compound having the alicyclic structure is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic dianhydride, 1,2,4. , 5-cyclohexanetetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid Anhydrides, decahydro-1,4: 5,8-dimethananaphthalene-2,3,6,7-tetracarboxylic dianhydride, and N, N ′-(1,4-phenylene) bis (1,3 The polyimide according to Item 2, which is one or more compounds selected from the group consisting of -dioxooctahydroisobenzofuran-5-carboxamide).
4). Item 4. The polyimide according to any one of Items 1 to 3, wherein 20 to 100 mol% of the diamine component is a compound represented by the following chemical formula (1).

(In the formula, A represents hydrogen, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, and Ar represents a divalent group selected from the following group: is there.)

(In the formula, B represents hydrogen, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.)
5). 20 to 100 mol% of the diamine component is 4,4′-bis (4-aminophenoxy) biphenyl and 4,4 ′-([1,1 ′: 3 ′, 1 ″: 3 ″, 1 Item 5. The polyimide according to any one of Items 1 to 4, which is one or more aromatic compounds selected from the group consisting of “″ -quarterphenyl] -4 ″, 6′-diylbis (oxy)) dianiline.
6). The glass transition temperature (Tg) is 250 ° C. or higher,
Item 6. The polyimide according to any one of Items 1 to 5, wherein a thickness direction retardation (Rth) in a 10 μm-thick film is 500 nm or less.

7). 7. A polyimide film mainly comprising the polyimide according to any one of items 1 to 6.
8). A flexible device using the polyimide film according to Item 7 as a substrate.
9. Forming the polyimide film according to Item 7 on a carrier substrate;
Forming a circuit on the polyimide film; and
The manufacturing method of the flexible device characterized by including the process of peeling the polyimide film in which the said circuit was formed in the surface from the said carrier substrate.

According to the present invention, it is particularly suitable as a substrate of a display device such as a liquid crystal display, an organic EL display, and electronic paper, and as a substrate of a light receiving device such as a light receiving element of a thin film solar cell, a touch sensor, or a touch panel. The polyimide which can be used for and a polyimide film can be provided.

In the display device (display device) as described above, in order to observe an image displayed by the element through the polyimide substrate, it is necessary to use polyimide having a high light transmittance in the visible light region for the substrate. In addition, when adopting a method of manufacturing a display device on a carrier substrate such as glass, after forming a polyimide substrate (polyimide film) on the carrier substrate, ultraviolet rays (directly or via other layers) on the polyimide substrate A cured resin layer may be formed, and the polyimide to be used is also required to have high light transmittance in the ultraviolet region. On the other hand, in order to employ a method of separating a polyimide substrate from a carrier substrate by laser light irradiation, it is necessary that the polyimide to be used absorbs the laser light.

The polyimide of the present invention has high light transmittance in the visible light region, and specifically, the yellowness (YI) in a film having a thickness of 10 μm is less than 3. If the yellowness (YI) is within this range, the transparency required for the substrate of the display device can be usually secured.

Furthermore, the polyimide of the present invention has a linear expansion coefficient from 50 ° C. to 200 ° C. of 55 ppm / K or less. When a polyimide film is used for a substrate of an electronic device such as a display device or a light receiving device, a necessary circuit is formed on the polyimide film. If the linear thermal expansion coefficient of the polyimide film is large, the warpage of the substrate is caused by this process. It can grow and be a problem. Therefore, in order to produce an electronic device having good characteristics without problems, it is usually necessary that the linear expansion coefficient from 50 ° C. to 200 ° C. is 55 ppm / K or less.

Further, the polyimide of the present invention transmits only ultraviolet rays in a specific wavelength region, and particularly has high light transmittance in a wavelength region of 365 nm or more and absorbs ultraviolet rays having a wavelength of 308 nm. Specifically, the light transmittance at a wavelength of 365 nm in a film having a thickness of 10 μm is 70% or more, and the light transmittance at a wavelength of 308 nm is less than 0.1%. If the light transmittance of polyimide at a wavelength of 308 nm is less than 0.1%, the polyimide substrate can be separated from a carrier substrate such as glass by irradiation with laser light. On the other hand, if the light transmittance at a wavelength of 365 nm in a film having a thickness of 10 μm is 70% or more, light having a longer wavelength (including ultraviolet light) passes through the polyimide from around the wavelength of 365 nm. A cured resin layer can be formed.

Therefore, this polyimide can be suitably used as a substrate for display devices such as liquid crystal displays, organic EL displays, and electronic paper. Furthermore, this polyimide can be suitably used as a substrate for a flexible device such as a substrate other than a display device, for example, a light receiving device such as a light receiving element of a thin film solar cell. Moreover, it can be suitably used as a substrate for touch sensors and touch panels.

The polyimide of the present invention has high transparency, and when the film has a film thickness of 10 μm, the yellowness (YI) measured in accordance with ASTM E313 is less than 3, preferably 2.8 or less, more preferably 2 .6 or less, more preferably 2.4 or less. In an embodiment in which higher transparency is required, the yellowness (YI) of a film having a thickness of 10 μm is 2.3 or less, more preferably 2.2 or less, and even more preferably 2.0 or less. preferable.

The polyimide of the present invention is controlled to have a relatively low linear expansion coefficient (CTE). When measured with a film having a thickness of 10 μm, the linear expansion coefficient at 50 to 200 ° C. is 55 ppm / K or less, preferably It is preferable that it is 50 ppm / K or less. In some embodiments, the linear expansion coefficient at 50 to 200 ° C. may be 45 ppm / K or less, more preferably 40 ppm / K or less, and even more preferably 35 ppm / K or less.

Further, when the polyimide of the present invention is a film having a thickness of 10 μm, the light transmittance at a wavelength of 365 nm is 70% or more, preferably 72% or more, more preferably 75% or more. In some embodiments, the transmittance of light having a wavelength of 365 nm in a film having a thickness of 10 μm may be 78% or more, more preferably 80% or more. If the light transmittance at a wavelength of 365 nm is low, it may be difficult to form an ultraviolet curable resin layer on the polyimide film (directly or via another layer), which may limit the manufacturing process of the flexible device. is there.

Furthermore, when the polyimide of the present invention is a film having a thickness of 10 μm, the light transmittance at a wavelength of 308 nm is less than 0.1%, preferably 0.09% or less. In some embodiments, the light transmittance at a wavelength of 308 nm in a film having a thickness of 10 μm is preferably less than 0.08%, more preferably less than 0.06%. If the light transmittance at a wavelength of 308 nm is high, that is, if the absorption of light at a wavelength of 308 nm by polyimide is insufficient, it may be difficult to separate the polyimide film from the carrier substrate using laser light of this wavelength.

The polyimide of the present invention preferably has a small thickness direction retardation (Rth). For example, when the film has a thickness of 10 μm, the thickness direction retardation (Rth) is 500 nm or less, and further 300 nm or less. It is preferable that The thickness direction retardation (Rth) is defined below.

Rth (nm) = [(nx + ny) / 2−nz] × d
(Nx, ny, and nz represent the refractive indexes of the X-axis, Y-axis, and Z-axis of the polyimide film, respectively, and d represents the thickness of the polyimide film. Here, the X-axis represents the maximum refractive index in the plane. (The Y axis is the direction perpendicular to the X axis in the plane, and the Z axis is the thickness direction perpendicular to these axes.)

Furthermore, the polyimide of the present invention preferably has a high glass transition temperature (Tg). For example, the glass transition temperature (Tg) is preferably 250 ° C. or higher, more preferably 280 ° C. or higher. In some embodiments, it may be preferred that the glass transition temperature (Tg) be 300 ° C. or higher, further 320 ° C. or higher, and even 350 ° C. or higher.

The details of the method for measuring the physical property values will be described in the examples described later.

The polyimide of the present invention is obtained from a tetracarboxylic acid component (the tetracarboxylic acid component includes a tetracarboxylic acid derivative such as tetracarboxylic dianhydride) and a diamine component, and the tetracarboxylic acid component and the diamine component are The main component is preferably a compound selected from the group consisting of aromatic compounds and compounds having an alicyclic structure. Including a large amount of an aromatic compound may cause coloring, and in particular, the tetracarboxylic acid component is preferably composed mainly of a compound having an alicyclic structure. That is, 80 mol% or more, particularly preferably 90 mol% or more of the tetracarboxylic acid component is preferably a compound having an alicyclic structure.

In one embodiment, the polyimide of the present invention preferably has a ratio of the compound having an alicyclic structure of 110 to 190 mol% in a total of 200 mol% of the tetracarboxylic acid component and the diamine component. is there.

Examples of the compound having an alicyclic structure that can be used as the tetracarboxylic acid component include 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2,3,4-cyclopentanetetracarboxylic acid. Dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic dianhydride, bicyclo [2,2,2] octane-2 , 3,5,6-tetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetra Carboxylic dianhydride, decahydro-1,4: 5,8-dimethananaphthalene-2,3,6,7-tetracarboxylic dianhydride, N, N ′-(1,4-phenylene) bis (1 , 3-Dioki (Sooctahydroisobenzofuran-5-carboxamide), 4,4′-methylenebis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 4,4 ′-(propane-2,2-diyl) bis (cyclohexane-) 1,2-dicarboxylic acid) dianhydride, 4,4′-oxybis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 4,4′-thiobis (cyclohexane-1,2-dicarboxylic acid) dianhydride 4,4′-sulfonylbis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 4,4 ′-(dimethylsilanediyl) bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 4,4 '-(Tetrafluoropropane-2,2-diyl) bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, octahydropentalene-1,3,4,6- Tracarboxylic dianhydride, bicyclo [2.2.1] heptane-2,3,5,6-tetracarboxylic dianhydride, 6- (carboxymethyl) bicyclo [2.2.1] heptane-2, 3,5-tricarboxylic dianhydride, bicyclo [2.2.2] octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] oct-5-ene-2 , 3,7,8-tetracarboxylic dianhydride, tricyclo [4.2.2.02,5] decane-3,4,7,8-tetracarboxylic dianhydride, tricyclo [4.2.2 .02,5] dec-7-ene-3,4,9,10-tetracarboxylic dianhydride, 9-oxatricyclo [4.2.1.02,5] nonane-3,4,7, Examples include 8-tetracarboxylic dianhydride. These may be used alone or in combination with a plurality of compounds.

In the present invention, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetra Carboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride, decahydro- 1,4: 5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic dianhydride, N, N ′-(1,4-phenylene) bis (1,3-dioxooctahydroiso It is preferable to use a compound selected from (benzofuran-5-carboxamide).

Examples of aromatic compounds that can be used as the tetracarboxylic acid component include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4 '-Biphenyltetracarboxylic dianhydride, 2,3,3', 4'-biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3 ', 4,4'-diphenylsulfone Tetracarboxylic dianhydride, 9,9-bis (3,4-dicarboxyphenyl) fluorene dianhydride, 1,4-difluoropyromellitic dianhydride, 1,4-bis (trifluoromethyl) pyromellit Acid dianhydride, 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride, 2,2-bis (3,4-dicarboxyphenyl) Hexafluoropropane dianhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, bis (3,4- Dicarboxyphenyl) sulfone dianhydride, m-terphenyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, p-terphenyl-3,4,3 ′, 4′-tetracarboxylic acid dianhydride Anhydride, biscarboxyphenyldimethylsilane dianhydride, bisdicarboxyphenoxydiphenyl sulfide dianhydride, sulfonyldiphthalic dianhydride, isopropylidenediphenoxybisphthalic dianhydride, and the like can be given. These may be used alone or in combination with a plurality of compounds. These aromatic compounds can be used in combination with the compound having the alicyclic structure.

The polyimide of the present invention is, for example, preferably a tetracarboxylic acid component, which is a compound having an alicyclic structure, preferably 80 mol% or more, particularly preferably 90 mol% or more, and one compound represented by the following chemical formula (1) It can obtain from the diamine component containing the above. In this case, 20 to 100 mol% of the diamine component is preferably a compound represented by the following chemical formula (1).

(In the formula, B represents hydrogen, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.)
The aryl group having 6 to 12 carbon atoms is preferably a substituted or unsubstituted phenyl group, more preferably an unsubstituted phenyl group.

In chemical formula (1), A is preferably hydrogen, and Ar is preferably a divalent group represented by the following chemical formula (2).

(In the formula, B represents hydrogen, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.)
In the chemical formula (2), B is preferably hydrogen or an aryl group having 6 to 12 carbon atoms, more preferably hydrogen or a substituted or unsubstituted phenyl group.

Although depending on the tetracarboxylic acid component used in combination and the other diamine component, in the case of the compound represented by the chemical formula (1) wherein B is hydrogen, the content of the compound in the diamine component is 20 to 90. It is preferable that it is mol%. When an aromatic diamine component is used in combination, the content of the compound represented by the chemical formula (1) in which B is hydrogen in the diamine component may be preferably 35 to 90 mol%. . On the other hand, in the case of the compound represented by the chemical formula (1) in which B is an aryl group, preferably a substituted or unsubstituted phenyl group, the content of the compound in the diamine component is 20 to 100 mol%, more preferably The content of the compound represented by the chemical formula (1) in which B is an aryl group in the diamine component is usually 30 to 100 mol%, even when an aromatic diamine component is used in combination. This range is preferred.

Examples of the compound represented by the chemical formula (1) include 4,4′-bis (4-aminophenoxy) biphenyl, 4,4 ′-([1,1′-biphenyl] -4,4′-diylbis (oxy )) Bis (2-phenoxyaniline), 4-((4 ′-(4-aminophenoxy)-[1,1′-biphenyl] -4-yl) oxy) -2-phenoxyaniline, 4,4′- ([1,1 ′: 3 ′, 1 ″: 3 ″, 1 ′ ″-quarterphenyl] -4 ″, 6′-diylbis (oxy)) dianiline, 4,4 ′-(naphthalene-1 , 5-diylbis (oxy)) dianiline, 4,4 ′-(naphthalene-1,6-diylbis (oxy)) dianiline, 4,4 ′-(naphthalene-1,4-diylbis (oxy)) dianiline, etc. It is done. These may be used alone or in combination with a plurality of compounds.

In the present invention, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4 ′-([1,1 ′: 3 ′, 1 ″: 3 ″, 1 ′ ″-quarterphenyl] It is preferable to use a compound selected from -4 ″, 6′-diylbis (oxy)) dianiline. In this case, although depending on the tetracarboxylic acid component used in combination and the other diamine component, 4,4′-bis (4-aminophenoxy) biphenyl and / or 4,4 ′-([1, The content of 1 ′: 3 ′, 1 ″: 3 ″, 1 ′ ″-quarterphenyl] -4 ″, 6′-diylbis (oxy)) dianiline is preferably 20 to 100 mol%. . In addition, the content of 4,4′-bis (4-aminophenoxy) biphenyl in the diamine component may be preferably 20 to 90 mol%, and may preferably be 35 to 90 mol%. .

Examples of other aromatic compounds that can be used as the diamine component include p-phenylenediamine, m-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, m-tolidine, and 4,4 ′. -Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-methylenedianiline, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4- Aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 5-amino-2- (4-aminophenyl) benzimidazole 4,4′-diaminobenzanilide, 2,2′-bis (trifluoromethyl) benzene Dizine, 3,3′-bis (trifluoromethyl) benzidine, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis [(4-aminophenoxy) phenyl] fluorene, 4,4′-bis (3-aminophenoxy) biphenyl, Bis (4-aminophenyl) sulfone, 3,3′-bis ((aminophenoxy) phenyl) propane, 2,2′-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (4- (4 -Aminophenoxy) diphenyl) sulfone, bis (4- (3-aminophenoxy) diphenyl) sulfone, octaful Robenzidine, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diaminobiphenyl, 3,3′-difluoro-4,4′-diaminobiphenyl, 4,4 '' -Diaminoterphenyl, 2,4-bis (4-aminoanilino) -6-anilino-1,3,5-triazine, 2,4-bis (4-aminoanilino) -6-diphenylamino-1,3 Examples include 5-triazine, 2,4-bis (3-aminoanilino) -6-anilino-1,3,5-triazine. These may be used alone or in combination with a plurality of compounds.

Examples of the compound having an alicyclic structure that can be used as the diamine component include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis ( Aminomethyl) cyclohexane, 4,4′-methylenebis (cyclohexylamine), bis (aminomethyl) norbornane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4- Diamino-2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino- 2-sec-butylcyclohexane, 1,4-diamino 2-tert-butylcyclohexane, 1,2-diaminocyclohexane, 1,3-diaminocyclobutane, 1,4-bis (aminomethyl) cyclohexane, 1,3-bis (aminomethyl) cyclohexane, diaminobicycloheptane, diamino Methylbicycloheptane, diaminooxybicycloheptane, diaminomethyloxybicycloheptane, isophoronediamine, diaminotricyclodecane, diaminomethyltricyclodecane, bis (aminocyclohexyl) methane, bis (aminocyclohexyl) isopropylidene 6,6'- Bis (3-aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, 6,6′-bis (4-aminophenoxy) -3,3,3 ′, 3 ′ -Tetramethyl-1,1'-spirobiinders For example. These may be used alone or in combination with a plurality of compounds.

Examples of other diamine components include 1,6-hexamethylene diamine, 1,10-decamethylene diamine, dimer diamine (a diamine obtained by reducing and aminating dimer acid, which is a dimer of a long-chain unsaturated fatty acid). ). These may be used alone or in combination with a plurality of compounds.

However, the polyimide of the present invention is not limited to those obtained from these tetracarboxylic acid components and diamine components.

The polyimide of the present invention can be obtained by preparing a polyamic acid by reacting a tetracarboxylic acid component and a diamine component and imidizing this polyamic acid. Specifically, for example, a polyimide film is obtained by applying a polyamic acid solution composition containing at least a polyamic acid and a solvent to a substrate, removing the solvent by heat treatment, and imidizing (dehydrating ring closure).

The polyamic acid used in the present invention can be obtained as a polyamic acid solution by reacting a tetracarboxylic acid component and a diamine component in a solvent. In this reaction, usually, a tetracarboxylic acid component and a diamine component are used in approximately equimolar amounts. Specifically, the molar ratio of the tetracarboxylic acid component to the diamine component [tetracarboxylic acid component / diamine component] is preferably about 0.90 to 1.10, more preferably about 0.95 to 1.05. . In order to suppress imidization, the reaction is performed at a relatively low temperature of, for example, 100 ° C. or less, preferably 80 ° C. or less. Although not limited, the reaction temperature is usually 25 ° C. to 100 ° C., preferably 40 ° C. to 80 ° C., more preferably 50 ° C. to 80 ° C., and the reaction time is about 0.1 to 24 hours, preferably It is preferably about 2 to 12 hours. By setting the reaction temperature and reaction time within the above ranges, a high molecular weight polyamic acid solution composition can be efficiently obtained. The reaction can be carried out in an air atmosphere, but usually it is suitably carried out in an inert gas atmosphere, preferably in a nitrogen gas atmosphere.

The solvent used for preparing the polyamic acid is not particularly limited. For example, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylformamide, N, N— Amide solvents such as dimethylpropionamide, N, N-dimethylisobutyramide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, δ -Cyclic ester solvents such as valerolactone, γ-caprolactone, ε-caprolactone, α-methyl-γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, glycol solvents such as triethylene glycol, m-cresol, p- Cresol, 3-chloropheno Le, 4-phenol-based solvents chlorophenol such as acetophenone, 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide, 1,4-dioxane, tetramethyl urea. The organic solvent to be used may be one type or a mixture of two or more types.

In the present invention, the logarithmic viscosity of the polyamic acid is not particularly limited, but the logarithmic viscosity in an N, N-dimethylacetamide solution having a concentration of 0.5 g / dL at 30 ° C. is 0.2 dL / g or more, preferably 0.4 dL. / G or more is preferable. When the logarithmic viscosity is 0.2 dL / g or more, the molecular weight of the polyamic acid is high, and the resulting polyimide has excellent mechanical strength and heat resistance.

In the polyamic acid solution composition used in the present invention, the solid content concentration resulting from the polyamic acid is not particularly limited, but is preferably 5% by mass to 45% with respect to the total amount of the polyimide precursor and the solvent. It is suitable that the content is 7% by mass, more preferably 7% by mass to 40% by mass, and still more preferably 9% by mass to 30% by mass. When the solid content concentration is lower than 5% by mass, productivity and handling during use may be deteriorated. When the solid content concentration is higher than 45% by mass, the fluidity of the solution may be lost.

The solution viscosity at 30 ° C. of the polyamic acid solution composition is not particularly limited, but is preferably 1000 Pa · sec or less, more preferably 0.1 to 500 Pa · sec, still more preferably 0.1 to 300 Pa · sec, particularly The handling is preferably 0.1 to 200 Pa · sec. When the solution viscosity exceeds 1000 Pa · sec, fluidity is lost, and uniform application to a support such as metal or glass may be difficult. If the solution viscosity is lower than 0.1 Pa · sec, dripping or repellency may occur when applied to a support such as metal or glass, and high-performance polyimide, polyimide film, polyimide flexible device substrate, etc. It may be difficult to get.

The polyamic acid solution composition may contain silica. Silica preferably has a particle size measured by a dynamic light scattering method of 100 nm or less, more preferably 1 to 60 nm, particularly preferably 1 to 50 nm, and further 10 to 30 nm. The content of silica is, for example, 1 to 100 parts by mass, more preferably 5 to 90 parts by mass, and particularly preferably 10 to 90 parts by mass with respect to 100 parts by mass of the total amount of the tetracarboxylic acid component and the diamine component. is there.

Silica is preferably added to and mixed with the polyamic acid solution as a colloidal solution in which colloidal silica is dispersed in an organic solvent. The solvent for colloidal silica is not particularly limited. For example, N, N-dimethylacetamide, N, N-dimethylformamide, propylene glycol monomethyl ether acetate, ethylene glycol mono-n-propyl ether, ethylene glycol, isopropanol, methanol, Examples thereof include methyl ethyl ketone, methyl isobutyl ketone, xylene, n-butanol, and propylene glycol monomethyl ether. The solvent of colloidal silica is preferably selected according to the solvent of the polyamic acid solution so that desired physical properties can be obtained, and is usually preferably a solvent having high compatibility with the polyamic acid solution. In addition, the organic solvent to be used may be one type or a mixture of two or more types.

The polyamic acid solution composition may contain a dehydrating agent and an imidization catalyst. Examples of the dehydrating agent include acetic anhydride, and examples of the imidization catalyst include imidazole compounds such as 1,2-dimethylimidazole, heterocyclic compounds containing nitrogen atoms such as isoquinoline, and basic compounds such as triethylamine and triethanolamine. Is mentioned.

In addition, the polyamic acid solution composition may contain additional components other than the above.

A polyimide film is obtained by applying the above polyamic acid solution composition to a substrate, removing the solvent by heat treatment and imidizing (dehydrating ring closure). The heat treatment conditions are not particularly limited, but it is preferable that the heat treatment is performed at a maximum heating temperature of 300 ° C. to 500 ° C., preferably 350 ° C. to 450 ° C. after drying in a temperature range of 50 ° C. to 150 ° C. Moreover, after apply | coating a polyamic acid solution composition to a base material and drying, the film | membrane of the obtained polyimide precursor composition (polyamic acid solution composition) is peeled from a base material, and the edge part of the film | membrane is peeled off. A polyimide film can also be obtained by imidization by heat treatment in a fixed state or without fixing the end of the membrane. Note that although the heat treatment can be performed in an air atmosphere, it is usually performed preferably in an inert gas atmosphere, preferably in a nitrogen gas atmosphere.

The polyimide film of the present invention is mainly composed of the polyimide of the present invention as described above, and if necessary, inorganic particles (filler) such as silica, various additives generally used for other polyimide films, etc. Can be contained. The thickness of the polyimide film of this invention can be suitably selected according to a use etc.

The flexible device of the present invention uses the polyimide film of the present invention as described above as a substrate, and can be manufactured as follows.

First, a polyamic acid solution composition is cast on a carrier substrate and imidized by heat treatment to form a polyimide film. Although there is no restriction | limiting in a carrier substrate, Generally glass substrates, such as soda-lime glass, borosilicate glass, an alkali free glass, are used. The method for casting the polyamic acid solution composition onto the glass substrate is not particularly limited, and examples thereof include conventionally known methods such as spin coating, screen printing, bar coater, and electrodeposition. The heat treatment conditions are not particularly limited, but it is preferable to dry at a temperature range of 50 ° C. to 150 ° C. and then treat at a maximum heating temperature of 300 ° C. to 500 ° C., preferably 350 ° C. to 450 ° C.

The thickness of the polyimide film to be formed is usually preferably 1 to 30 μm. When the thickness is less than 1 μm, the polyimide film cannot maintain sufficient mechanical strength, and when used as a flexible device substrate or the like, the polyimide film cannot withstand stress and may be destroyed. Moreover, when the thickness of a polyimide film exceeds 30 micrometers, it will become difficult to thin a flexible device. In order to make the film thinner while maintaining sufficient resistance as a flexible device, the thickness of the polyimide resin film is more preferably 2 to 10 μm.

On the polyimide film formed as described above, for example, a circuit necessary for a display device such as a liquid crystal display, an organic EL display, and electronic paper, a light receiving device such as a solar cell, and CMOS is formed. This process varies depending on the type of device. For example, when a TFT liquid crystal display device is manufactured, an amorphous silicon TFT is formed on a polyimide film. The TFT includes a gate metal layer, a silicon nitride gate dielectric layer, and an ITI pixel electrode. Further, a structure necessary for the liquid crystal display can be formed by a known method.

Next, the polyimide film having a circuit or the like formed on the surface is peeled off from the carrier substrate. There is no restriction | limiting in particular in the peeling method, For example, it can peel by irradiating a laser etc. from the carrier substrate side. For peeling by laser light irradiation, it is preferable to irradiate laser light having a wavelength of 308 nm. Since the polyimide film of the present invention has a very low light transmittance at a wavelength of 308 nm, that is, excellent in light absorption, the polyimide film can be easily peeled off from the carrier substrate by irradiating a laser beam with a wavelength of 308 nm. it can. In this way, the flexible device of the present invention can be obtained.

Examples of the flexible device in the present invention include a display device such as a liquid crystal display, an organic EL display, and electronic paper, a light receiving device such as a solar cell, and a CMOS. Moreover, a touch sensor and a touch panel can also be mentioned. The present invention is particularly suitable for application to a device that is desired to be thin and flexible.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to a following example.

The abbreviations of the compounds used in the examples are as follows.
CpODA: Norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic dianhydride DNDA: Decahydro-1,4 : 5,8-dimethananaphthalene-2,3,6,7-tetracarboxylic dianhydride H-PMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride CBDA: 1,2,3 4-Cyclobutanetetracarboxylic dianhydride HTAC (PPD): N, N ′-(1,4-phenylene) bis (1,3-dioxooctahydroisobenzofuran-5-carboxamide)
H-BPDA: Dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic dianhydride 6FDA: 4,4 ′-(2,2-hexafluoroisopropylene) diphthalic dianhydride 1,4-CHDA: 1,4-diaminocyclohexane BAPB: 4,4′-bis (4-aminophenoxy) biphenyl BAFL: 9,9-bis (4-aminophenyl) fluorene DABAN: 4,4′-diaminobenzanilide 4-APBP-DP : 4,4 ′-([1,1 ′: 3 ′, 1 ″: 3 ″, 1 ′ ″-quarterphenyl] -4 ″, 6′-diylbis (oxy)) dianiline PPD: p- Phenylenediamine m-TD: m-tolidine ODA: 4,4'-diaminodiphenyl ether TFMB: 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl

The measurement method of characteristics used in the examples is shown below.

(Light transmittance)
The light transmittance of the polyimide film at a wavelength of 365 nm and a wavelength of 308 nm was measured using a spectrophotometer U-2910 (manufactured by Hitachi High-Technologies Corporation).

(Yellowness)
The yellowness (YI) of the polyimide film was measured using a spectrophotometer U-2910 (manufactured by Hitachi High-Technologies Corporation) in accordance with ASTM E313.

(Laser peel strength)
A laminate of glass and a polyimide film obtained by applying a polyamic acid solution composition onto a glass plate and imidizing was used as a test sample. Using a laser peeling tester (IPEX-860, manufactured by Light Machinery), laser was irradiated from the glass plate side of the test sample, and the energy of the laser was gradually increased from 100 mJ / cm ² to measure the energy at which the film peeled.

(Linear expansion coefficient (CTE) and glass transition temperature (Tg))
A polyimide film having a thickness of 10 μm is cut into a strip shape having a width of 4 mm to form a test piece, and TMA / SS6100 (manufactured by SII Nano Technology Co., Ltd.) is used. The temperature was raised to 400 ° C. The linear expansion coefficient from 50 ° C. to 200 ° C. was determined from the obtained TMA curve. Moreover, Tg was calculated from the inflection point of the TMA curve.

(Thickness direction phase difference)
A phase difference (Rth) in the thickness direction was measured at a measurement wavelength of 590 nm and an incident angle of 40 ° using a phase difference measuring device KOBRA-WR (manufactured by Oji Scientific Instruments).

[Example 1]
430 g of N-methyl-2-pyrrolidone was added as a solvent to a glass reaction vessel having an internal volume of 500 ml equipped with a stirrer and a nitrogen gas introduction / discharge pipe, and 1,4-CHDA 2.2773 g (0.0199 mol), BAPB29 3934 g (0.0798 mol) and CpODA 38.3293 g (0.0997 mol) were added and stirred at 30 ° C. to obtain a polyamic acid solution.

This polyamic acid solution is applied onto a base glass plate by a bar coater, heated from 50 ° C. to 350 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, and heated at 350 ° C. for 5 minutes. A polyimide film having a thickness of 10 μm was formed on the glass plate.

The obtained polyimide film was peeled off from the glass plate and each characteristic was measured. The results are shown in Table 1.

[Example 2]
Implemented except that 430 g of N-methyl-2-pyrrolidone, 4.9104 g (0.0430 mol) of BAPB, 23.7668 g (0.0645 mol) of BAPB, and 41.228 g (0.1075 mol) of CpODA were used as solvents. A polyimide film was obtained in the same manner as in Example 1. Table 1 shows the measurement results of each characteristic.

Example 3
Implemented except that 430 g of N-methyl-2-pyrrolidone, 7.9896 g (0.0700 mol) of BAPB, 17.1868 g (0.0466 mol) of BAPB, and 44.8236 g (0.1166 mol) of CpODA were used as solvents. A polyimide film was obtained in the same manner as in Example 1. Table 1 shows the measurement results of each characteristic.

Example 4
Implementation was performed except that 430 g of N-methyl-2-pyrrolidone, 11.6388 g (0.1019 mol) of BAPB, 9.3888 g (0.0255 mol) of BAPB, and 48.9724 g of CpODA (0.1274 mol) were used as solvents. A polyimide film was obtained in the same manner as in Example 1. Table 1 shows the measurement results of each characteristic.

Example 5
As a solvent, N-methyl-2-pyrrolidone 430 g, 1,4-CHDA 4.9255 g (0.0431 mol), BAPB 19.8667 g (0.0539 mol), BAFL 3.7575 g (0.0108 mol), CpODA 41.4502 g (0 .1078 mol) was used in the same manner as in Example 1 to obtain a polyimide film. Table 1 shows the measurement results of each characteristic.

Example 6
As a solvent, 440 g of N-methyl-2-pyrrolidone, 3.4576 g of 1,4-CHDA (0.0303 mol), 26.0326 g (0.0707 mol) of BAPB, and 30.5098 g of DNDA (0.1009 mol) were used at 370 ° C. A polyimide film was obtained in the same manner as in Example 1 except that the heat treatment was performed. Table 1 shows the measurement results of each characteristic.

Example 7
As a solvent, 440 g of N-methyl-2-pyrrolidone, 3.9807 g (0.0349 mol) of 1,4-CHDA, 29.9707 g (0.0813 mol) of BAPB, and 26.0487 g (0.1162 mol) of H-PMDA A polyimide film was obtained in the same manner as in Example 1 except that it was used. Table 1 shows the measurement results of each characteristic.

Example 8
N-methyl-2-pyrrolidone 450 g, 1,4-CHDA 2.6809 g (0.0235 mol), BAPB 20.0.1847 g (0.0548 mol), CpODA 24.0649 g (0.0626 mol), CBDA 3.0695 g (0 0.157 mol) was used in the same manner as in Example 1 to obtain a polyimide film. Table 1 shows the measurement results of each characteristic.

Example 9
N-methyl-2-pyrrolidone 440 g, 1,4-CHDA 2.7022 g (0.0237 mol), BAPB 20.4352 g (0.0552 mol), HTAC (PPD) 36.9526 g (0.0789 mol) are used as solvents. A polyimide film was obtained in the same manner as in Example 1 except that. Table 1 shows the measurement results of each characteristic.

Example 10
N-methyl-2-pyrrolidone 440 g, 1,4-CHDA 3.4343 g (0.0301 mol), BAPB 25.8573 g (0.0702 mol), and H-BPDA 30.7083 g (0.1003 mol) were used as the solvent. Obtained a polyimide film in the same manner as in Example 1. Table 1 shows the measurement results of each characteristic.

Example 11
The same procedure as in Example 1 was performed except that 430 g of N-methyl-2-pyrrolidone, 40.3094 g (0.0774 mol) of 4-APBP-DP, and 29.6906 g (0.0774 mol) of CpODA were used and heat-treated at 390 ° C. Thus, a polyimide film was obtained. Table 2 shows the measurement results of each characteristic.

Example 12
As a solvent, 430 g of N-methyl-2-pyrrolidone, 26.1108 g (0.0502 mol) of 4-APBP-DP, 5.4245 g (0.0502 mol) of PPD, and 38.4648 g (0.1003 mol) of CpODA were used at 370 ° C. A polyimide film was obtained in the same manner as in Example 1 except that the heat treatment was performed. Table 2 shows the measurement results of each characteristic.

Example 13
As a solvent, 430 g of N-methyl-2-pyrrolidone, 20.27919 g (0.0389 mol) of 4-APBP-DP, 12.3990 g (0.0584 mol) of m-TD, and 37.3291 g of CpODA (0.0973 mol) were used. A polyimide film was obtained in the same manner as in Example 1 except that the heat treatment was performed at ° C. Table 2 shows the measurement results of each characteristic.

Example 14
N-methyl-2-pyrrolidone 430 g, 4-APBP-DP 29.9264 g (0.0575 mol), BAFL 8.5837 g (0.0246 mol), and CpODA 31.4898 g (0.0821 mol) were used as solvents at 370 ° C. A polyimide film was obtained in the same manner as in Example 1 except that the heat treatment was performed. Table 2 shows the measurement results of each characteristic.

Example 15
As a solvent, 410 g of N-methyl-2-pyrrolidone, 42.9053 g (0.0824 mol) of 4-APBP-DP, 7.5912 g (0.0206 mol) of BAPB, 39.5034 g (0.1030 mol) of CpODA, and 370 ° C. A polyimide film was obtained in the same manner as in Example 1 except that the heat treatment was performed. Table 2 shows the measurement results of each characteristic.

[Comparative Example 1]
A polyimide film was prepared in the same manner as in Example 1 except that 410 g of N-methyl-2-pyrrolidone, 37.7002 g (0.1177 mol) of TFMB, 52.998 g of 6FDA (0.1177 mol) were used, and heat treatment was performed at 370 ° C. Obtained. Table 2 shows the measurement results of each characteristic.

[Comparative Example 2]
A polyimide film was obtained in the same manner as in Example 1 except that 410 g of N-methyl-2-pyrrolidone, 42.4650 g (0.2120 mol) of ODA, and 47.5350 g (0.2120 mol) of H-PMDA were used. Table 2 shows the measurement results of each characteristic. This polyimide film could not be peeled even when the laser energy was increased to 300 mJ / cm ² .

Claims

A polyimide obtained from a tetracarboxylic acid component and a diamine component,
The yellowness in a film having a thickness of 10 μm is less than 3,
The linear expansion coefficient from 50 ° C. to 200 ° C. is 55 ppm / K or less,
A polyimide having a light transmittance of 70% or more at a wavelength of 365 nm and a light transmittance of less than 0.1% at a wavelength of 308 nm in a 10 μm thick film.
The polyimide according to claim 1, wherein 90 mol% or more of the tetracarboxylic acid component is a compound having an alicyclic structure.
The compound having the alicyclic structure is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, dicyclohexyl-3,3 ′, 4,4′-tetracarboxylic dianhydride, 1,2,4. , 5-cyclohexanetetracarboxylic dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid Anhydrides, decahydro-1,4: 5,8-dimethananaphthalene-2,3,6,7-tetracarboxylic dianhydride, and N, N ′-(1,4-phenylene) bis (1,3 The polyimide according to claim 2, which is one or more compounds selected from the group consisting of -dioxooctahydroisobenzofuran-5-carboxamide).
The polyimide according to any one of claims 1 to 3, wherein 20 to 100 mol% of the diamine component is a compound represented by the following chemical formula (1).

(In the formula, A represents hydrogen, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, and Ar represents a divalent group selected from the following group: is there.)

(In the formula, B represents hydrogen, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.)
20 to 100 mol% of the diamine component is 4,4′-bis (4-aminophenoxy) biphenyl and 4,4 ′-([1,1 ′: 3 ′, 1 ″: 3 ″, 1 The compound according to any one of claims 1 to 4, which is one or more aromatic compounds selected from the group consisting of '' '-quarterphenyl] -4' ', 6'-diylbis (oxy)) dianiline. Polyimide.
The glass transition temperature (Tg) is 250 ° C. or higher,
The polyimide according to any one of claims 1 to 5, wherein a thickness direction retardation (Rth) of a film having a thickness of 10 µm is 500 nm or less.
A polyimide film mainly composed of the polyimide according to any one of claims 1 to 6.
A flexible device using the polyimide film according to claim 7 as a substrate.
Forming the polyimide film according to claim 7 on a carrier substrate;
Forming a circuit on the polyimide film; and
The manufacturing method of the flexible device characterized by including the process of peeling the polyimide film in which the said circuit was formed in the surface from the said carrier substrate.