JP2022018374A - Polyimide film, laminate of polyimide film and inorganic substrate, and flexible electronic device - Google Patents

Abstract

To provide a polyimide film having high colorless transparency and high ultraviolet absorptivity, and a flexible electronic device using the same.SOLUTION: A polyimide is obtained by blending 625 ppm or more and 20,000 ppm or less of zinc oxide particles and/or 750 ppm or more and 20,000 ppm or less of zinc sulfide particles, and 680 ppm or more and 10,000 ppm or less of zirconium oxide particles and/or 1,000 ppm or more and 10,000 ppm or less of zirconium silicate particles, with a colorless polyimide resin.EFFECT: A total addition amount can be suppressed by energizing ultraviolet absorption capability of a zinc oxide with a light diffusion effect by a zirconium compound, and accordingly whitening of a film is suppressed, high transparency is maintained, and UV laser cutting properties are improved. A device having little ultraviolet degradation can be obtained by using the film as a member of a flexible electronic device.SELECTED DRAWING: None

Description

The present invention relates to a polyimide film that is colorless and has excellent transparency, a laminate of the polyimide film and an inorganic substrate, and a flexible electronic device using the polyimide film as a member.

Polyimide film has excellent heat resistance and good mechanical properties, and is widely used in the electric and electronic fields as a flexible material. However, since a general polyimide film is colored yellowish brown, it cannot be applied to a part such as a display device that requires light transmission.
On the other hand, display devices are becoming thinner and lighter, and further flexibility is required. Therefore, attempts are being made to replace the substrate material from a glass substrate with a flexible polymer film substrate, but the colored polyimide film is a substrate material for a liquid crystal display that displays by turning on / off light transmission. It cannot be used as a peripheral circuit such as a TAB or COF on which a drive circuit of a display device is mounted, or can be applied only to a small part such as the back side of a reflective display system or a self-luminous display device.

Against this background, the development of colorless and transparent polyimide films is underway. As a typical example, there is an attempt to develop a colorless transparent polyimide film using a fluorinated polyimide resin, a semi-lipid ring type or a full alicyclic polyimide resin (Patent Documents 1 to 3). These films are less colored and have transparency. Further, a method of heat-treating these colorless polyimides while spraying a gas having an oxygen content has been proposed (Patent Document 4), and it has been shown that coloring is further suppressed.

Japanese Unexamined Patent Publication No. 11-106508 Japanese Unexamined Patent Publication No. 2002-146021 Japanese Unexamined Patent Publication No. 2002-348374 WO2008 / 146637A Gazette

Since the colored polyimide has absorption in the ultraviolet region, it is easy to process with a UV laser. However, since the colorless polyimide as shown above has a low absorbance, excessive energy is required for processing with a UV laser, smearing is likely to occur during processing, and discoloration of the cut surface may occur. Further, when such a colorless polyimide film is used for a member of an electronic device such as a flexible display or a touch sensor, it is directly exposed to ultraviolet rays of the outside world. Since the conventional colored polyimide has been used in the housing of electronic and electrical equipment in principle, the deterioration of the polyimide film itself by ultraviolet rays has not become a problem. However, when a colorless polyimide film is used as a member, the problem that ultraviolet deterioration occurs in the polyimide film itself or other members used in the vicinity of the film becomes apparent.

As a result of diligent research to solve such a problem, the present inventors have made a polyimide having a high ultraviolet shielding property while maintaining the colorlessness and transparency of the film by blending a specific amount of a specific inorganic component. By developing a film and applying the polyimide film to a flexible electronic device, we have realized an electronic device that can be expected to have high light resistance.
That is, the present invention has the following configuration.
[1]
The yellow index is 10 or less, the total light transmittance is 85% or more, the tensile elastic modulus is 3 GPa or more, the CTE is -5 ppm / ° C. to + 55 ppm / ° C., and the following (a) and (b) are included as inorganic fillers. A characteristic polyimide film.
(A) Zinc oxide particles of 625 ppm or more and 20000 ppm or less, and / or zinc sulfide particles of 750 ppm or more and 20000 ppm or less (b) Zinc oxide particles of 680 ppm or more and 10000 ppm or less, and / or zirconium silicate particles of 1000 ppm or more and 10000 ppm or less [ 2]
The polyimide film according to [1], wherein the inorganic filler has a particle size of 400 nm or less.
[3]
A laminate containing the polyimide film and the inorganic substrate according to the above [1] or [2], wherein the polyimide film and the inorganic substrate are in direct contact with each other.
[4]
It is a laminate containing the polyimide film and the inorganic substrate according to the above [1] or [2], and is characterized in that the polyimide film and the inorganic substrate are adhered to each other via a condensate layer of a silane coupling agent. body.
[5]
A flexible electronic device using the polyimide film according to the above [1] or [2] as a member.

The present invention preferably has the following configuration.
[6]
A method for manufacturing a flexible electronic device, which comprises forming an electronic device on the polyimide film surface of the laminate according to the above [3] or [4], and then peeling the electronic device from the laminate together with the polyimide film.
[7]
An electronic device is formed on the polyimide film surface of the laminate according to the above [3] or [4], and then laser light is irradiated from the inorganic substrate side of the laminate, and then the electronic device is peeled off together with the polyimide film. A method for manufacturing flexible electronic devices.

The present invention is a colorless and highly transparent polyimide film containing zinc oxide particles and / or zinc sulfide particles as an inorganic filler and zirconium oxide particles and / or zirconium silicate particles in a predetermined amount. It is generally known that zinc oxide has an ultraviolet absorbing effect. Therefore, it is known that zinc oxide is added to a film to obtain an ultraviolet shielding effect. However, it is necessary to add a considerable amount of zinc oxide in order to obtain a sufficient UV shielding effect. Since the refractive index of zinc oxide is higher than that of the polyimide resin, when the addition amount is increased, whitening of the film is unavoidable due to the light scattering effect, the haze value of the film increases, and the transparency decreases.
On the other hand, zirconium oxide (zirconia) has a higher refractive index than zinc oxide, and zirconium silicate (zircone) has a double refractive index while having a refractive index similar to that of zinc oxide. Therefore, in each case, the light scattering effect is exhibited by adding a small amount, and by combining the two, it is possible to obtain a sufficient ultraviolet absorbing ability with an addition amount such that the whitening of the film is not noticeable.
Since the light scattering effect of fine particles depends on the particle size, it is possible to enhance the scattering effect of the target wavelength by matching the particle size with the desired light wavelength. Therefore, by matching the ultraviolet absorbing region of zinc oxide with the particles of zirconium oxide and / or zirconium silicate that are responsible for the light scattering effect, it is possible to obtain a higher ultraviolet absorbing ability.

<Polyimide film>
The polyimide film of the present invention preferably has a thickness of 3 μm or more and 120 μm or less. It is preferably 4 μm or more, more preferably 5 μm or more, and further preferably 8 μm or more because the mechanical properties are good. Further, it is preferably 100 μm or less, more preferably 80 μm or less, and further preferably 60 μm or less because the transparency becomes good.

The polyimide film of the present invention has a yellow index of 10 or less. It is preferably 4 or less, more preferably 3.5 or less, and further preferably 3 or less because the transparency is good. Since the lower the yellow index is, the lower limit is not particularly limited, but industrially, it may be 0.1 or more, and 0.2 or more may be used.

The polyimide film of the present invention has a total light transmittance of 85% or more. It is preferably 87% or more, more preferably 88% or more, and further preferably 89% or more because the transparency becomes good. The upper limit is not particularly limited, but industrially, it may be 99% or less, and may be 98% or less.

The haze of the polyimide film of the present invention is preferably 2 or less, more preferably 1.5 or less, still more preferably 1 or less, and even more preferably 0.8 or less. The lower limit of the haze is not particularly limited, but industrially, 0.01 or more is sufficient, and 0.05 or more may be sufficient.

The polyimide film of the present invention has a tensile elastic modulus in both the MD direction and the TD direction of 3 GPa or more, preferably 3.5 GPa or more, and more preferably 4 GPa or more. Further, it is preferably 8 GPa or less, more preferably 7.5 GPa or less, and further preferably 7 GPa or less.

The polyimide film of the present invention has a CTE of −5 ppm / ° C. to +55 ppm / ° C. in both the MD and TD directions, preferably 0 ppm / ° C. to + 50 ppm / ° C., and more preferably 5 ppm / ° C. to + 45 ppm / ° C. be.

<Chemical composition of polyimide film>
The polyimide is obtained by a polycondensation reaction between a tetracarboxylic acid anhydride and a diamine.
In the present invention, a film made of polyimide having the following composition is preferable.
When the total acid component is 100% by mass, the tetracarboxylic acid anhydride containing 70% by mass or more of the alicyclic tetracarboxylic acid anhydride and when the total amine component is 100% by mass, an amide bond is formed in the molecule. When the total acid component of the polyimide having a chemical structure obtained by condensation polymerization with a diamine containing 70% by mass or more of the diamine having is 100% by mass, the alicyclic tetracarboxylic acid anhydride is contained in 70% by mass or more. Aroma when 100% by mass of the polyimide / total acid component having a chemical structure obtained by condensate of tetracarboxylic acid anhydride and diamine containing 70% by mass or more of a diamine having a trifluoromethyl group in the molecule. Obtained from a tetracarboxylic acid anhydride containing 70% by mass or more of a group tetracarboxylic acid anhydride and a diamine containing at least 70% by mass of a diamine having a sulfur atom in the molecule when the total amine component is 100% by mass. When the total acid component of the polyimide having the above chemical structure is 100% by mass, a tetracarboxylic acid anhydride containing at least 30% by mass of a tetracarboxylic acid containing a trifluoromethyl group in the molecule and at least trifluoromethyl. A polyimide having a chemical structure obtained by condensation polymerization with a diamine containing 70% by mass or more of a diamine having a group in the molecule.

Examples of the alicyclic tetracarboxylic acid anhydride in the present invention include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid and 1,2,3,4-cyclohexane. Tetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3', 4,4'-bicyclohexyltetracarboxylic acid, bicyclo [2,2,1] heptane-2,3,5,6 -Tetracarboxylic acid, bicyclo [2,2,2] octane-2,3,5,6-tetracarboxylic acid, bicyclo [2,2,2] octo-7-en-2,3,5,6-tetra Carboxylic acid, tetrahydroanthracene-2,3,6,7-tetracarboxylic acid, tetradecahydro-1,4: 5,8: 9,10-trimethanoanthracene-2,3,6,7-tetracarboxylic acid, Decahydronaphthalene-2,3,6,7-tetracarboxylic acid, decahydro-1,4: 5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic acid, decahydro-1,4-ethano- 5,8-methanonaphthalene-2,3,6,7-tetracarboxylic acid, norbornan-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornan-5,5'',6 6''-Tetracarboxylic acid (also known as "norbornan-2-spiriro-2'-cyclopentanone-5'-spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid" ), Methylnorbornan-2-spiro-α-cyclopentanone-α'-spiro-2''-(methylnorbornan) -5,5'',6,6''-tetracarboxylic acid, norbornan-2-spiro -Α-Cyclohexanone-α'-Spiro-2''-Norbornane-5,5'', 6,6''-Tetracarboxylic acid (also known as "norbornan-2-spiriro-2'-cyclohexanone-6'-spiro-" 2''-norbornan-5,5'', 6,6''-tetracarboxylic acid "), methylnorbornan-2-spiro-α-cyclohexanone-α'-spiro-2''-(methylnorbornan) -5 , 5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α-cyclopropanol-α'-spiro-2''-norbornan-5,5'', 6,6''- Tetracarboxylic acid, norbornan-2-spiro-α-cyclobutanone-α'-spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α-cyclo Heptanone- α'-Spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α-cyclooctanone-α'-spiro-2''-norbornan- 5,5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α-cyclononanonone-α'-spiro-2''-norbornan-5,5'', 6,6''-tetra Carboxylic acid, norbornan-2-spiro-α-cyclodecanone-α'-spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α-cyclounde Cannon-α'-Spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α-cyclododecanone-α'-spiro-2''- Norbornan-5,5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α-cyclotridecanone-α'-spiro-2''-norbornan-5,5'', 6,6 '' -Tetracarboxylic acid, norbornan-2-spiro-α-cyclotetradecanone-α'-spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid, norbornan-2 -Spiro-α-cyclopentadecanone-α'-Spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α- (methylcyclopentanone) ) -Α'-Spiro-2''-norbornan-5,5'', 6,6''-tetracarboxylic acid, norbornan-2-spiro-α- (methylcyclohexanone) -α'-spiro-2'' -Norbornane-5,5'', 6,6''-Tetracarboxylic acids such as tetracarboxylic acids, and acid anhydrides thereof. Among these, dianhydride having two acid anhydride structures is preferable, and in particular, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and 1,2,3,4-cyclohexanetetracarboxylic acid are preferable. Acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride is preferred, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic Acid dianhydride is more preferred, and 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride is even more preferred. These may be used alone or in combination of two or more.

Examples of the aromatic tetracarboxylic acid anhydride in the present invention include 4,4'-(2,2-hexafluoroisopropyridene) diphthalic acid, 4,4'-oxydiphthalic acid, and bis (1,3-dioxo-1,3). -Dihydro-2-benzofuran-5-carboxylic acid) 1,4-phenylene, bis (1,3-dioxo-1,3-dihydro-2-benzofuran-5-yl) benzene-1,4-dicarboxylate, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl) bis (benzene-1,4-diyloxy)] dibenzene-1,2-dicarboxylic acid Acid, 3,3', 4,4'-benzophenonetetracarboxylic acid, 4,4'-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl) bis (toluene-2, 5-diyloxy)] dibenzene-1,2-dicarboxylic acid, 4,4'-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl) bis (1,4-xylene-2) , 5-Diyloxy)] dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl) bis (4) -Isopropyl-toluene-2,5-diyloxy)] dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1) -Diyl) bis (naphthalene-1,4-diyloxy)] dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1,1-dioxide) -3,3-diyl) bis (benzene-1,4-diyloxy)] dibenzene-1,2-dicarboxylic acid, 4,4'-benzophenonetetracarboxylic acid, 4,4'-[(3H-2,1-) Benzoxathiol-1,1-dioxide-3,3-diyl) bis (toluene-2,5-diyloxy)] dibenzene-1,2-dicarboxylic acid, 4,4'-[(3H-2,1-benz) Oxathiol-1,1-dioxide-3,3-diyl) bis (1,4-xylene-2,5-diyloxy)] dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'- (3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl) Bis (4-isopropyl-toluene-2,5-diyloxy)] Dibenzene-1,2-dicarboxylic acid, 4,4 '-[4,4'-(3H-2,1-benzoxathio) Lu-1,1-dioxide-3,3-diyl) bis (naphthalen-1,4-diyloxy)] dibenzene-1,2-dicarboxylic acid, 3,3', 4,4'-benzophenone tetracarboxylic acid, 3,3', 4,4'-benzophenone tetracarboxylic acid, 3,3', 4,4'-diphenylsulfone tetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 2,3. 3', 4'-biphenyltetracarboxylic acid, pyromellitic acid, 4,4'-[spiro (xanthene-9,9'-fluorene) -2,6-diylbis (oxycarbonyl)] diphthalic acid, 4,4' -[Spiro (xanthene-9,9'-fluorene) -3,6-diylbis (oxycarbonyl)] Tetracarboxylic acids such as diphthalic acid, and acid anhydrides thereof. The aromatic tetracarboxylic acids may be used alone or in combination of two or more.

In the present invention, a tricarboxylic acid or a dicarboxylic acid may be used in addition to the tetracarboxylic acid anhydride.
Examples of tricarboxylic acids include aromatic tricarboxylic acids such as trimellitic acid, 1,2,5-naphthalene tricarboxylic acid, diphenyl ether-3,3', 4'-tricarboxylic acid, and diphenylsulfone-3,3', 4'-tricarboxylic acid. An acid or an alkylene such as a hydrogenated additive of the above aromatic tricarboxylic acid such as hexahydrotrimellitic acid, ethylene glycol bistrimerite, propylene glycol bistrimerite, 1,4-butanediol bistrimerite, polyethylene glycol bistrimerite. Glycolbitrimeritate and these monoanhydrides and esterified products can be mentioned. Among these, monoanhydride having one acid anhydride structure is preferable, and in particular, trimellitic acid anhydride and hexahydrotrimellitic acid anhydride are preferable. These may be used alone or in combination of two or more.

Examples of the dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 4,4'-oxydibenzenecarboxylic acid, and the above aromatic dicarboxylic acid such as 1,6-cyclohexanedicarboxylic acid. Hydrogen additives, oxalic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, azelaioic acid, sebacic acid, undecadioic acid, dodecanedioic acid, 2-methylsuccinic acid, and acid acidates thereof. Alternatively, an esterified product or the like can be mentioned. Among these, aromatic dicarboxylic acids and hydrogen additives thereof are preferable, and terephthalic acid, 1,6-cyclohexanedicarboxylic acid, 4,4'-oxydibenzenecarboxylic acid are particularly preferable. The dicarboxylic acids may be used alone or in combination of two or more.

As the diamine having an amide bond in the molecule in the present invention, aromatic diamines and alicyclic amines can be mainly used.
Examples of aromatic diamines include 2,2'-dimethyl-4,4'-diaminobiphenyl, 1,4-bis [2- (4-aminophenyl) -2-propyl] benzene, and 1,4-bis. (4-Amino-2-trifluoromethylphenoxy) benzene, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'- Bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone , 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoro Propane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 4-amino-N- (4-aminophenyl) benzamide, 3,3'-diaminodiphenyl ether , 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-trifluoromethyl-4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenylsulfide, 3,4'-diaminodiphenyl Sulfur, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4 '-Diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4 '-Diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-Aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] propane, 1,2-bis [4- (4-aminophenoxy) phenyl] propane, 1 , 3-Bis [4- (4-aminophenoxy) phenyl] propane, 2,2 -Bis [4- (4-aminophenoxy) phenyl] propane, 1,1-bis [4- (4-aminophenoxy) phenyl] butane, 1,3-bis [4- (4-aminophenoxy) phenyl] butane , 1,4-Bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,3-bis [4- (4-aminophenoxy) ) Phenyl] butane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-amino) Phenoxy) -3-methylphenyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-Aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoro Propane, 1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-) Aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfoxide, bis [4 -(4-Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,3-bis [4- (4- (4-) Aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 4,4'-bis [ (3-Aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) phenyl] propane, 3,4' -Diaminodiphenyl sulfide, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, bis [4- (3-aminophenoxy) phenyl] Methan, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bi Su [4- (3-aminophenoxy) phenyl] ethane, bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4,4'-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4 '-Bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4'-bis [4- (4-Amino-α, α-dimethylbenzyl) phenoxy] diphenyl sulfone, bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) Phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6) -Trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-fluorophenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [ 4- (4-Amino-6-methylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-cyanophenoxy) -α, α-dimethylbenzyl] benzene, 3,3'-diamino-4,4'-diphenoxybenzophenone, 4,4'-diamino-5,5'-diphenoxybenzophenone, 3,4'-diamino-4,5'-diphenoxybenzophenone, 3, 3'-Diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3 '-Diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4'-diamino-4,5'-dibiphenoxybenzophenone, 3,3'- Diamino-4-biphenoxybenzophenone, 4,4'-diamino-5-biphenoxybenzophenone, 3,4'-diamino-4-biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone, 1, 3-Bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-phenoyl) Xybenzoyl) benzene, 1,4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,4-bis (3-amino-) 4-Bifenoxybenzoyl) Benzene, 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-amino-5-biphenoxybenzoyl) benzene, 2,6-bis [ 4- (4-Amino-α, α-dimethylbenzyl) phenoxy] benzonitrile, 4,4'-[9H-fluoren-9,9-diyl] bisaniline (also known as "9,9-bis (4-aminophenyl)) Fluorene "), Spiro (xanthen-9,9'-fluorene) -2,6-diylbis (oxycarbonyl)] bisaniline, 4,4'-[spiro (xanthen-9,9'-fluoren) -2,6- Diylbis (oxycarbonyl)] bisaniline, 4,4'-[spiro (xanthen-9,9'-fluorene) -3,6-diylbis (oxycarbonyl)] bisaniline, 5-amino-2- (p-aminophenyl) Benzeneoxazole, 6-amino-2- (p-aminophenyl) benzoxazole, 5-amino-2- (m-aminophenyl) benzoxazole, 6-amino-2- (m-aminophenyl) benzoxazole, 2, 2'-p-phenylenebis (5-aminobenzoxazole), 2,2'-p-phenylenebis (6-aminobenzoxazole), 1- (5-aminobenzoxazolo) -4- (6-aminobenzoxazole) Oxazolo) Benzene, 2,6- (4,4'-diaminodiphenyl) benzo [1,2-d: 5,4-d'] bisoxazole, 2,6- (4,4'-diaminodiphenyl) benzo [1,2-d: 4,5-d'] bisoxazole, 2,6- (3,4-diaminodiphenyl) benzo [1,2-d: 5,4-d'] bisoxazole, 2, 6- (3,4'-diaminodiphenyl) benzo [1,2-d: 4,5-d'] bisoxazole, 2,6- (3,3'-diaminodiphenyl) benzo [1,2-d: 5,4-d'] bisoxazole, 2,6- (3,3-'-diaminodiphenyl) benzo [1,2-d: 4,5-d'] bisoxazole and the like can be mentioned. Further, a part or all of the hydrogen atoms on the aromatic ring of the aromatic diamine may be substituted with a halogen atom, an alkyl group or an alkoxyl group having 1 to 3 carbon atoms, or a cyano group, and further, the carbon number 1 may be substituted. A part or all of the hydrogen atom of the alkyl group or the alkoxyl group of ~ 3 may be substituted with a halogen atom.

Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, and 1,4-diamino-2-n-propyl. Cyclohexane, 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, 4,4'-methylenebis (2,6-dimethylcyclohexylamine), 9,10-bis (4-aminophenyl) adenine, 2,4-bis (4-) Aminophenyl) cyclobutane-1,3-dimethyl dicarboxylate, and the like can be mentioned.

As the diamine having an amide bond in the molecule, 4-amino-N- (4-aminophenyl) benzamide is preferable. The diamine having an amide bond is preferably 70% by mass or more, more preferably 80% by mass or more, and more preferably 90% by mass or more of the total diamine.
Examples of the diamine having a trifluoromethyl group include 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 1,4-bis (4-amino-2-trifluoromethylphenoxy) benzene, and 2, 2'-Trifluoromethyl-4,4'-diaminodiphenyl ether is preferred. When a diamine compound having a fluorine atom in these molecules, particularly a diamine having a trifluoromethyl group in the molecule is used, the amount used is preferably 70% by mass or more, more preferably 80% by mass or more, and further, 80% by mass or more of the total diamine. Is preferably used in an amount of 90% by mass or more.

<Inorganic filler>
Zinc oxide used as the inorganic filler (a) in the present invention is an oxide of zinc represented by the chemical formula ZnO, and is also called zinc white or zinc white. Zinc oxide is contained in the polyimide film in the form of particles. The content is 625 ppm or more, preferably 800 ppm or more, more preferably 1200 ppm or more, more preferably 20000 ppm or less, preferably 12000 ppm or less, still more preferably 6000 ppm or less with respect to the mass of the polyimide resin. Here, the unit ppm of the zinc oxide content is a unit in terms of mass (mg / kg).
Specific examples of commercially available zinc oxide particles include ZnO-350, ZnO-510, ZnO-610, ZnO-650 (manufactured by Sumitomo Osaka Cement Co., Ltd.), MZ-300, MZY-303S, MZ-306X, and MZ-. 500, MZY-505S, MZY-510M3S, MZ-506X, MZ-510HPSX (manufactured by Teika), XZ-F series, XZ-100P, FINEX-30, FINEX-30S-LP2, FINEX-30S-LPT, FINEX- 30W-LP2, FINEX-30W-LPT, FINEX-50, FINEX-50S-LP2, FINEX-50W-LP2, FINEX-50S-LPT, FINEX-50W-LPT, ZINCA-20, fine zinc oxide (Sakai Chemical Industry Co., Ltd.) , F-1, F-2 (manufactured by HakusuiTech Co., Ltd.), FZO-50 (manufactured by Ishihara Sangyo Co., Ltd.) and the like can be exemplified. These zinc oxides may be used alone or in combination of two or more.

The zinc sulfide used as the inorganic filler (a) in the present invention is a zinc sulfide represented by the chemical formula ZnS. The content of the zinc sulfide particles is 750 ppm or more, preferably 900 ppm or more, more preferably 1200 ppm or more, more preferably 20000 ppm or less, preferably 12000 ppm or less, still more preferably 6000 ppm or less, based on the mass of the polyimide resin. Here, the unit ppm of the zinc sulfide content is a unit in terms of mass (mg / kg).
In the present invention, it is essential that zinc oxide particles, zinc sulfide particles, or both are contained in the polyimide film. When both zinc oxide particles and zinc sulfide particles are used, it is preferable to prepare so that the total of both particles is in the range of 750 ppm or more and 20000 ppm or less. If the blending amount of zinc oxide particles and zinc sulfide particles exceeds this range, the whitening of the film cannot be ignored and the haze value may increase. If the amount is less than this range, the ultraviolet absorption effect may be insufficient. be. The predetermined range is a range in which sufficient ultraviolet absorption ability (ultraviolet shielding ability) and high transparency of visible light (colorlessness, transparency) can be achieved at the same time when used in combination with zirconium oxide or zirconium silicate described later.

Zirconium oxide used as the inorganic filler (b) in the present invention is an oxide of zirconium represented by the chemical formula ZrO ₂ , and is also called zirconia. Zirconium oxide is contained in the polyimide film in the form of particles. The content is 680 ppm or more, preferably 900 ppm or more, more preferably 1200 ppm or more, more preferably 10,000 ppm or less, preferably 8000 ppm or less, still more preferably 6000 ppm or less with respect to the mass of the polyimide resin. Here, the unit ppm of the zirconium oxide content is a unit in terms of mass (mg / kg).
The zirconium silicate used as the inorganic filler (b) in the present invention is a silicate of zirconium represented by the chemical formula ZrSiO ₄ or ZrO ₂ · SiO ₂ , and is also called zircon. The content of zirconium silicate is 1000 ppm or more, preferably 1200 ppm or more, more preferably 2000 ppm or more, and 10,000 ppm or less, preferably 8000 ppm or less, still more preferably 6000 ppm or less, based on the mass of the polyimide resin. Here, the unit ppm of the zirconium silicate content is a unit in terms of mass (mg / kg).
In the present invention, it is essential that either or both of the zirconium oxide particles and the zirconium silicate particles are contained in the polyimide film. When both zirconium oxide particles and zirconium silicate particles are used, it is preferable to prepare so that the total of both particles is in the range of 1000 ppm or more and 20000 ppm or less. If the blending amount of zirconium oxide particles and zirconium silicate particles exceeds this range, the whitening of the film cannot be ignored and the haze value may increase. If this range is not reached, the ultraviolet absorption capacity of zinc oxide or zinc sulfide May not be fully supported. Such a predetermined range is a range in which sufficient ultraviolet absorption ability (ultraviolet shielding ability) and high transparency of visible light (colorlessness, transparency) can be achieved at the same time.
It is known that zirconium contains hafnium, which is the same Group 4 element, as an impurity. The two are very similar in chemical properties and are difficult to separate. Therefore, products generally sold as zirconium compounds contain hafnium compounds. In the present invention, if the hafnium content is 5% by mass or less with respect to the total of zirconium and hafnium, the total amount including hafnium is treated as zirconium.

The particle size of the inorganic filler is preferably 400 nm or less, more preferably 350 nm or less, and further preferably 300 nm or less. Further, it is preferably 10 nm or more, more preferably 20 nm or more. By setting it within the above range, the scattering effect can be enhanced.

In the polyimide film of the present invention, in addition to zinc oxide, zinc sulfide, zirconium oxide, and zirconium silicate, the following inorganic fillers are added and contained in the polyimide as a lubricant to impart fine irregularities to the film surface and to make the film slippery. It is preferable to improve.
As the lubricant, fine particles having an average particle size of about 0.03 μm to 3 μm of inorganic or organic can be used, and specific examples thereof include titanium oxide, alumina, silica, calcium carbonate, calcium phosphate, calcium hydrogen phosphate, calcium pyrophosphate, and the like. Examples include magnesium oxide, calcium oxide and clay minerals.

<Manufacturing method of polyimide film and laminate>
In general, a polyimide film is obtained by reacting a tetracarboxylic acid anhydride with a diamine in a solvent to obtain a solution of polyamic acid as a polyimide precursor, and the polyamic acid solution is applied to a temporary support, dried, and further amidic acid bonded. Is chemically converted to an imide bond to obtain a polyimide film. In some cases, polyamic acid is converted to polyimide in a solution to form a polyimide solution, which is then applied to a temporary support and dried to form a polyimide film. Further, the polymer may be separated from the polyamic acid solution or the polyimide solution by a reprecipitation operation or the like and redissolved in another solvent to form a film using the obtained solution.

The inorganic filler is added by adding the tetracarboxylic acid anhydride and the diamine in the solvent in a state where the inorganic filler is dispersed in the solvent in advance before the reaction, or adding the inorganic filler to the polyimide or polyamic acid solution after the polymerization. The method can be used. A precursor of an inorganic particle (a compound that produces a predetermined inorganic particle through a process such as decomposition by heating) is added to the solution in advance, and the inorganic particle is formed in the process of drying or a chemical reaction from an amic acid bond to an imide bond. A method of producing and containing it in a film can also be exemplified.

As the temporary support used in the present invention, glass, a metal plate, a metal belt, a metal drum, a polymer film, a metal foil, or the like can be used. In the present invention, it is preferable to use a long and flexible temporary support, and a film such as polyethylene terephthalate, polyethylene naphthalate, or polyimide can be used as the temporary support. It is one of the preferable embodiments to perform a mold release treatment on the surface of the temporary support.

When a polyimide solution or a polyimide precursor solution is applied to a temporary support, dried until the residual solvent amount of the coating film reaches 5 to 40% by mass, and the semi-dried state is obtained, the semi-dried coating film is a self-supporting film. It becomes possible to peel it off from the temporary support. In this case, the self-supporting film is peeled off from the temporary support, and both ends of the self-supporting film are clipped or pierced into a pin to grip the film, and the film is conveyed in a heating environment for further drying. A polyimide film can be obtained by performing a chemical reaction by heating.

In the present invention, the self-supporting film may be stretched. The stretching may be in either the longitudinal direction of the film (MD direction) or the width direction (TD) of the film, or both. Stretching in the longitudinal direction of the film can be performed by using the speed difference of the transport roll or the difference in speed between the transport roll and the speed after gripping both ends. Stretching in the film width direction can be performed by widening the gripped clip or pin. Stretching and heating may be performed at the same time. The draw ratio can be arbitrarily selected from 1.00 times to 2.5 times.

Using the above-mentioned temporary support as an inorganic substrate, a polyimide solution or a polyamic acid solution is applied to the inorganic substrate, and the polyimide film of the present invention is dried and, if necessary, chemically reacted without peeling from the inorganic substrate. And an inorganic substrate can be obtained. In this method, the polyimide film and the inorganic substrate are in direct contact with each other.

In the present invention, the laminate of the present invention can be obtained by laminating a polyimide film on an inorganic substrate. A known adhesive or adhesive can be used for bonding. Further, the polyimide film and / or the inorganic substrate can be surface-treated to join the two to form a laminated body. Examples of the surface treatment include silane coupling agent treatment and vacuum or atmospheric pressure plasma treatment. When a silane coupling agent is used for the surface treatment, the polyimide film and the inorganic substrate are in a form of being bonded via a condensate of a silane upling material.

The silane coupling agent in the present invention is not particularly limited, but one having an amino group or an epoxy group is preferable. Specific examples of the silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (amino). Ethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2- (3,4-Epoxycyclohexyl) Ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilanevinyl trichlorsilane, vinyl Trimethoxysilane, vinyl triethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxy Propyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3 -Acryloxypropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane, 3-Chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isoxapropyltriethoxysilane, tris- (3-trimethoxysilyl) Propyl) isocyanurate, chloromethylphenetyltrimethoxysilane, chloromethyltrimethoxysilane and the like. Of these, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl)-are preferred. 3-Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, 2- (3, 4-Epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, aminophenyltrimethoxysilane, amino Examples thereof include phenetyltrimethoxysilane and aminophenylaminomethylphenetyltrimethoxysilane. When heat resistance is required in the process, it is desirable to connect Si and an amino group with an aromatic.

As an eclectic method of both, a polymer solution or a polymer precursor solution is used as a self-supporting semi-dry film, that is, a solvent and a polymer, or a film containing a solvent and a polymer precursor is used as an inorganic substrate. It is also possible to use a method of adhering and then drying or causing a chemical reaction with drying to form a laminate of a polymer film and an inorganic substrate. According to this method, the polyimide film and the inorganic substrate are in direct contact with each other.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. The physical property values in the production examples and the examples were measured by the following methods.

<Filler particle size>
The center diameter _D50 obtained from the SALD-2300 diffractive particle size distribution measuring device manufactured by Shimadzu Corporation was used as the particle size of each filler.

<Measurement of film thickness>
The measurement was performed using a micrometer (Millitron 1245D manufactured by Fine Wolf Co., Ltd.).

<Tension modulus, tensile strength (breaking strength), and breaking elongation>
The film was cut into strips of 100 mm × 10 mm in the flow direction (MD direction) and the width direction (TD direction) at the time of coating, and used as test pieces. Using a tensile tester (manufactured by Shimadzu, Autograph (R) model name AG-5000A), the tensile elastic modulus and tensile strength in each of the MD and TD directions under the conditions of a tensile speed of 50 mm / min and a chuck distance of 40 mm. And the elongation at break were obtained, and the average value of the measured values in the MD direction and the TD direction was obtained.

<Line expansion coefficient (CTE)>
The stretch ratio of the film was measured under the following conditions for each dimension in the flow direction (MD direction) and width direction (TD direction) at the time of coating, and the temperature was 30 ° C. to 45 ° C. and 45 ° C. to 60 ° C. The expansion / contraction rate / temperature was measured at intervals of 15 ° C., this measurement was performed up to 300 ° C., the average value of all the measured values was calculated as CTE, and the average value of the measured values in the MD direction and the TD direction was obtained.
Device name; TMA4000S manufactured by MAC Science
Sample length; 20 mm
Sample width; 2 mm
Temperature rise start temperature; 25 ° C
Temperature rise end temperature; 300 ° C
Temperature rise rate; 5 ° C / min
Atmosphere; Argon

<Haze>
The haze of the film was measured using HAZEMETER (NDH5000, manufactured by Nippon Denshoku Co., Ltd.). A D65 lamp was used as the light source. The same measurement was performed three times, and the arithmetic mean value was adopted.

<Total light transmittance>
The total light transmittance (TT) of the film was measured using HAZEMETER (NDH5000, manufactured by Nippon Denshoku Co., Ltd.).

<Ultraviolet transmittance>
The transmittance at a wavelength of 350 nm was defined as the ultraviolet transmittance by the spectrophotometric system.

<Yellow index>
Using a color meter (ZE6000, manufactured by Nippon Denshoku Co., Ltd.) and a C2 light source, the tristimulatory value XYZ value of the film was measured according to ASTM D1925, and the yellowness index (YI) was calculated by the following formula. The same measurement was performed three times, and the arithmetic mean value was adopted.
YI = 100 × (1.28X-1.06Z) / Y

<Film warp>
A film cut into a square having a size of 100 mm × 100 mm is used as a test piece, and the test piece is placed on a flat surface at room temperature so as to have a concave shape, and the distances from the flat surface at the four corners (h1rt, h2rt, h3rt, h4rt: unit mm). ) Was measured, and the average value was taken as the amount of warpage (mm).

[Production Example 1 Production of Polyamic Acid Solution A (PAA Solution A)]
After nitrogen substitution in the reaction vessel equipped with a nitrogen introduction tube, a reflux tube and a stirring rod, 22.73 parts by mass of 4,4'-diaminobenzanilide (DABAN) was added to 21.1 parts by mass of N, N-. It is dissolved by adding it to dimethylacetamide (DMAc), and then 19.32 parts by mass of 1,2,3,4-cyclobutanetetracarboxylic acid anilides (CBDA) is added separately as a solid, and then 24 at room temperature. Stir for hours. Then, 173.1 parts by mass of DMAc was added and diluted to obtain a polyamic acid solution A having an NV of 10% and a reduction viscosity of 3.10 dl / g.

[Production Example 2 Production of Polyamic Acid Solution B (PAA Solution B)]
After nitrogen substitution in the reaction vessel equipped with a nitrogen introduction tube, a reflux tube and a stirring rod, 32.02 parts by mass of 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl (TFMB) was added to 279. Dissolved in 9 parts by mass of N, N-dimethylacetamide (DMAc), then 9.81 parts by mass of 1,2,3,4-cyclobutanetetracarboxylic acid unihydrate (CBDA) and 15.51 parts by mass. (ODPA) was added separately in solid form, and then stirred at room temperature for 24 hours. Then, a polyamic acid solution B having a solid content of 17% by mass and a reducing viscosity of 3.60 dl / g was obtained.

[Production Example 3 Production of Polyimide Solution C (PI Solution C)]
32.02 parts by mass of 2,2'-ditrifluoromethyl-4,4'while introducing nitrogen gas into a reaction vessel equipped with a nitrogen introduction tube, a Dean Stark tube and a recirculation tube, a thermometer, and a stirring rod. -Diaminobiphenyl (TFMB), 230 parts by weight N, N-dimethylacetamide (DMAc) was added and completely dissolved, followed by 44.42 parts by weight of 4,4'-(2,2-hexafluoroisopropylidene). ) Diphthalic acid dianhydride (6FDA) was added in portions as a solid, and then stirred at room temperature for 24 hours. Then, a polyamic acid solution Caa having a solid content of 25% by mass and a reduction end of 1.10 dl / g was obtained.
Next, 204 parts by mass of DMAc was added to the obtained polyamic acid solution to dilute the polyamic acid concentration to 15% by mass, and then 1.3 parts by mass of isoquinoline was added as an imidization accelerator. Then, while stirring the polyamic acid solution, 12.25 parts by mass of acetic anhydride was slowly added dropwise as an imidizing agent. Then, stirring was continued for 24 hours and a chemical imidization reaction was carried out to obtain a polyimide solution Cpi.
Next, 100 parts by mass of the obtained polyimide solution was transferred to a reaction vessel equipped with a stirrer and a stirrer, and 150 parts by mass of methanol was slowly dropped while stirring. As a result, precipitation of a powdery solid was confirmed. rice field.
Then, the powder contained in the reaction vessel was dehydrated and filtered, washed with methanol, vacuum dried at 50 ° C. for 24 hours, and then heated at 260 ° C. for another 5 hours to obtain a polyimide powder Cpd. 20 parts by mass of the obtained polyimide powder was dissolved in 80 parts by mass of DMAc to obtain a polyimide solution C.

[Production Example 4 Production of Polyimide Solution D (PI Solution D)]
While introducing nitrogen gas into a reaction vessel equipped with a nitrogen introduction tube, a Dean Stark tube and a recirculation tube, a thermometer, and a stirring rod, 120.5 parts by mass of 4,4'-diaminodiphenyl sulfone (4,4') was introduced. -DDS), 51.6 parts by mass of 3,3'-diaminodiphenyl sulfone (3,3'-DDS) and 500 parts by mass of gamma butyrolactone (GBL) were added. Subsequently, 217.1 parts by mass of 4,4'-oxydiphthalic acid unihydrate (ODPA), 223 parts by mass of GBL, and 260 parts by mass of toluene were added at room temperature, and then the temperature was raised to 160 ° C. The mixture was heated under reflux at 160 ° C. for 1 hour for imidization. After the imidization was completed, the temperature was raised to 180 ° C., and the reaction was continued while extracting toluene. After the reaction for 12 hours, the oil bath was removed and the temperature was returned to room temperature, GBL was added so that the solid content had a concentration of 20% by mass, and a polyimide solution D was obtained.

[Production Example 5 Production of Polyamic Acid Solution E (PAA Solution E)]
161 parts by mass of 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl (TFMB) and 1090 parts by mass of N-methyl-2-pyrrolidone in a reaction vessel equipped with a nitrogen introduction tube, a reflux tube and a stirring rod under a nitrogen atmosphere. After mixing and stirring the parts to dissolve, 112 parts by mass of 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride (CHDA) was added separately at room temperature as a solid, and the mixture was stirred at room temperature for 12 hours. Next, 400 parts by mass of xylene was added as an azeotropic solvent, the temperature was raised to 180 ° C., and the reaction was carried out for 3 hours to separate the azeotropic generated water. After confirming that the outflow of water was completed, xylene was removed while raising the temperature to 190 ° C. over 1 hour to obtain a polyamic acid solution E.

[Production Example 6 Production of Polyamic Acid Solution F (PAA Solution F)]]
After nitrogen substitution in the reaction vessel equipped with a nitrogen introduction tube, a reflux tube and a stirring rod, 11.36 parts by mass of 4,4'-diaminobenzanilide (DABAN) and 16.01 parts by mass of 2,2'. -Ditrifluoromethyl-4,4'-diaminobiphenyl (TFMB) was completely dissolved by adding 21.1 parts by mass of N, N-dimethylacetamide (DMAc). Then, 19.32 parts by mass of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) was added separately as a solid, and then stirred at room temperature for 24 hours. Then, 173.1 parts by mass of DMAc was added and diluted to obtain a polyamic acid solution F having an NV of 10% and a reduction viscosity of 3.10 dl / g.

The polyimide solution and the polyamic acid solution (polyimide precursor solution) obtained in the production example were formed into a film by the following method, and the optical properties and mechanical properties were measured. The results are shown in Table 1.
(How to obtain a film for measuring physical properties by itself)
A polyimide solution or a polyamic acid solution was applied to the center of a glass plate having a side of 30 cm, approximately 20 cm square, using a bar coater so that the final thickness was 25 ± 2 μm, and dry nitrogen was gently poured. After heating in an inert oven at 100 ° C. for 30 minutes and confirming that the amount of residual solution in the coating film was 40% by mass or less, the mixture was heated in a muffle furnace substituted with dry nitrogen at 300 ° C. for 20 minutes. Then, it is taken out from the muffle furnace, the end of the dry coating film (film) is raised with a utility knife, and it is carefully peeled from the glass to obtain a film.

[Inorganic filler]
The inorganic fillers shown in Table 2 were prepared and used in Examples and Comparative Examples. The refractive index described in the reference is a typical numerical value published in the chemical handbook, various physical property tables, etc.

(Example 1)
In the poamidic acid solution F obtained in the production example, ZnO-65 as an inorganic filler was added to the resin component at a mass ratio of 2000 ppm, ZrO2-10 was added to the resin component at a mass ratio of 700 ppm, and the lubricant was SiO2-80. Was added at a mass ratio of 3000 ppm to the resin component and uniformly dispersed.
Using a device equipped with a roll-to-roll type comma coater, a continuous drying furnace, and a heat treatment furnace in the air air-conditioned at 25 ° C. and 45% RH, first, a polyamic acid solution in which the inorganic filler is dispersed is tentatively prepared. A polyethylene terephthalate film A4100 (manufactured by Toyobo Co., Ltd., hereinafter abbreviated as PET film), which is a support, is coated on a non-slip material surface so that the final film thickness is 25 μm, and then heated to 110 ° C. in a continuous drying oven. And dried for 15 minutes to obtain a self-supporting film having a residual solvent amount of 23% by mass. The self-supporting film is peeled off from the A4100 film that has been used as a support, passed through a pin tenter having a pin sheet on which pins are arranged, and the film end is gripped by inserting the pin into the pin so that the film does not break and is unnecessary. The pin sheet spacing was adjusted so that sagging did not occur, and the film was transported under the conditions of 200 ° C. for 5 minutes, 250 ° C. for 5 minutes, and 300 ° C. for 10 minutes to proceed with solvent removal and imidization reaction. .. Then, the film was cooled to room temperature in 3 minutes, and the portions of the film having poor flatness were cut off with a slitter and wound into a roll to obtain a roll of a film (actual 1) having a width of 580 mm and a length of 200 m.
Table 3 shows the evaluation results of the obtained film (actual 1).

(Examples 2 to 17) (Comparative Examples 1 to 7)
Similarly, a film was produced and evaluated in the same manner as in Example 1 by combining the polyamic acid solution or the polyimide solution shown in Table 3, Table 4, Table 5, and Table 6 with the inorganic filler. The results are shown in Table 3, Table 4, Table 5, and Table 6. When the ultraviolet transmittance is 50% or less, the processability with a UV laser is good.

Comparative Example 1 is a system to which an inorganic filler other than a lubricant is not added, and has a high ultraviolet transmittance and a poor shielding effect. Comparative Example 2 and Comparative Example 3 are systems in which zinc oxide particles and zirconium silicate particles are added alone. Although it is added in a larger amount than the amount of the filler added in Examples 1 to 12, the ultraviolet transmittance exceeds 50%. On the other hand, Example 13 is a system in which zirconium oxide is added to Comparative Example 2 and zinc oxide is added to Comparative Example 3 so that the inorganic fillers (a) and (b) coexist. It can be seen that the ultraviolet transmittance is kept low due to the synergistic effect of the two.
Comparative Example 5 is a system to which no inorganic filler is added. The slipperiness of the film was significantly reduced, and it was difficult to wind the film without wrinkles. Example 15, Comparative Example 6 and Comparative Example 7 are experiments for obtaining the minimum amount at which a synergistic effect can be obtained, and the lower limit of the filler addition can be obtained from here.

(Examples 18 to 21, Comparative Examples 8 and 9)
ZnO-300 and ZrSO4-700 as inorganic fillers were uniformly dispersed in the poamidic acid solution D obtained in the production example according to Table 4. Next, a polyamic acid solution in which a filler was dispersed on a display glass (370 mm × 470 mm, 0.7 mm thick glass substrate: OA10G manufactured by Nippon Electric Glass Co., Ltd.) was applied with a bar coater so that the final film thickness was 16 μm. , Heat in an inert oven gently flowing dry nitrogen at 100 ° C. for 20 minutes, confirm that the residual solvent amount of the coating film is 40% by mass or less, and then in a muffle oven replaced with dry nitrogen at 300 ° C. After heating for 15 minutes in the oven, drying and a conversion reaction from polyamic acid to polyimide were carried out to obtain a laminate composed of a polyimide film and a glass substrate.
The polyimide film was peeled off from the obtained laminate, and the optical characteristics were measured. The results are shown in Table 4.
In Comparative Examples 8 and 9, the haze value is high and the transparency is low.

(Application Example 1)
First, the polyimide film (actual 1) obtained in Example 1 was cut into a rectangle having a size of 360 mm × 460 mm. Next, a UV / O3 irradiator (SKR1102N-03 manufactured by LAN Technical) was used as the film surface treatment, and the layer ₍ a) was irradiated with UV / O3 for ₃ minutes. At this time, the distance between the UV / O3 lamp and the film was set to ₃₀ mm.
Spray 3-aminopropyltrimethoxysilane (KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent on display glass (glass substrate of 370 mm x 470 mm, thickness 0.7 mm: OA10G manufactured by Nippon Electric Glass Co., Ltd.). It was applied with a coater. The glass substrate used was washed with pure water, dried, and then irradiated with a UV / O3 irradiator (SKR1102N- ₀₃ manufactured by LAN Technical) for 1 minute to dry wash.
Next, the glass substrate coated with the silane coupling agent is set on a roll laminator equipped with a silicone rubber roller, and first, 500 ml of pure water is dropped on the surface coated with the silane coupling agent with a dropper so as to spread over the entire substrate. Wet.
The surface-treated surface of the multilayer polyimide film subjected to the surface treatment is laminated so as to face the silane coupling agent-coated surface of the glass substrate, that is, the surface wetted with pure water, and sequentially from one side of the glass substrate with a rotating roll. A temporary laminate was obtained by laminating the glass substrate and the polyimide film under pressure while extruding pure water between the polyimide film and the glass substrate. The laminator used was a laminator with an effective roll width of 650 mm manufactured by MCK, and the bonding conditions were air source pressure: 0.5 MPa, laminating speed: 50 mm / sec, roll temperature: 22 ° C, environmental temperature 22 ° C, humidity. It was 55% RH.
The obtained temporary laminate was heat-treated in a clean oven at 200 ° C. for 10 minutes to obtain a laminate LB-E01 composed of a multilayer polyimide film and a glass substrate.

A tungsten film (thickness 75 nm) is formed on the polyimide film surface of the obtained laminate LB-E01 by the following steps, and a silicon oxide film (thickness 150 nm) is laminated as an insulating film without being exposed to the atmosphere. did. Next, a silicon oxide nitride film (thickness 100 nm) to be a base insulating film was formed by a plasma CVD method, and an amorphous silicon film (thickness 54 nm) was laminated and formed without being exposed to the atmosphere.

A TFT element was manufactured using the obtained amorphous silicon film. First, the amorphous silicon thin film is patterned to form a silicon region having a predetermined shape, and a gate insulating film is formed, a gate electrode is formed, a source region or a drain region is formed by doping the active region, and an interlayer insulating film is formed. , The source electrode and the drain electrode were formed, and the activation treatment was performed to prepare an array of P-channel TFTs.
The polyimide film portion was burnt off with a UV-YAG laser along the inside of the outer circumference of the TFT array by about 0.5 mm, and further, the excimer laser was irradiated with a line beam of 308 nm from the glass substrate surface with an energy amount of 85 mJ / square cm. The overlap rate of the line beams was set to 50%. Then, peeling was performed from the end of the cut so as to scoop up with a thin razor-shaped blade to obtain a flexible A3 size TFT array. The peeling was possible with a very small force, and it was possible to peel without damaging the TFT. The cut surface by the UV-YAG laser was not disturbed, and no splattering such as smear was observed. The obtained flexible TFT array did not show any deterioration in performance even when wound around a round bar having a diameter of 5 mm, and maintained good characteristics.

(Application Example 2)
Using the laminated body LB-E21 obtained in Example 21, an amorphous silicon TFT is formed on the polyimide surface in the same manner as in Application Example 1, and the periphery is similarly trimmed with a UV-YAG laser, and further, Application Example 1 is performed. The excimer laser was irradiated from the surface side of the glass substrate under the same conditions as above, and the mixture was peeled off from the glass substrate in the same manner to obtain a flexible TFT array. The obtained flexible TFT array did not show any deterioration in performance even when wound around a round bar having a diameter of 5 mm, and maintained good characteristics.

(Application Comparative Example 1)
Using the polyimide film ratio 3 obtained in Comparative Example 3, the laminate was laminated on a glass substrate by the same operation as in Application Example 1 to obtain a laminated body LB-C03. The obtained laminated body LB-C03 was used to form a TFT in the same manner, and the periphery was similarly trimmed with a UV-YAG laser and then peeled off from the glass substrate to obtain a flexible TFT array. Jaggedness was seen on the cut surface by the UV-YAG laser, and about 20% of the TFTs were malfunctioning. As a result of detailed analysis of the malfunctioning part, a fine peeling part was found in a part of the insulating layer on the glass surface side in the element. This is presumed to be due to the effect of excimer laser light transmitted through the polyimide film.

As described above, the polyimide film of the present invention has an appropriate UV shielding performance, maintains high transparency and colorlessness, and can be formed into a film with the minimum necessary amount of inorganic filler. The film has excellent physical properties.
The polyimide film of the present invention is widely used as a member of a flexible and lightweight display device, a switch element such as a touch panel, a pointing device, etc., which requires transparency, via a laminate with an inorganic substrate such as a glass substrate. can do.

Claims (5)

The yellow index is 10 or less, the total light transmittance is 85% or more, the tensile elastic modulus is 3 GPa or more, the CTE is -5 ppm / ° C. to + 55 ppm / ° C., and the following (a) and (b) are included as inorganic fillers. A characteristic polyimide film.
(A) Zinc oxide particles of 625 ppm or more and 20000 ppm or less, and / or zinc sulfide particles of 750 ppm or more and 20000 ppm or less (b) Zinc oxide particles of 680 ppm or more and 10000 ppm or less, and / or zirconium silicate particles of 1000 ppm or more and 10000 ppm or less. The polyimide film according to claim 1, wherein the inorganic filler has a particle size of 400 nm or less. A laminate including the polyimide film and the inorganic substrate according to claim 1, wherein the polyimide film and the inorganic substrate are in direct contact with each other. A laminate including the polyimide film and the inorganic substrate according to claim 1 or 2, wherein the polyimide film and the inorganic substrate are adhered to each other via a condensate layer of a silane coupling agent. A flexible electronic device using the polyimide film according to claim 1 or 2 as a member.