WO2022202769A1 - Poly(amic acid), poly(amic acid) solution, polyimide, polyimide substrate and layered product, and methods for producing these - Google Patents

Abstract

The purpose of the present invention is to provide: a polyimide which exhibits high heat resistance and high transparency and which exhibits improved adhesion to inorganic films; a poly(amic acid) that is a precursor of the polyimide; a polyimide substrate and a layered product; and methods for producing these.　The foregoing can be achieved by: a poly(amic acid) which is a product of a polyaddition reaction between a diamine and a tetracarboxylic acid dianhydride, wherein the diamine includes 1,4-phenylenediamine and 1,3-bis(3-aminopropyl)tetramethyldisiloxane and the tetracarboxylic acid dianhydride includes 3,3,4,4-biphenyltetracarboxylic acid dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluorene acid dianhydride; and a polyimide and a polyimide substrate obtained from the poly(amic acid).

Description

Polyamic acid, polyamic acid solution, polyimide, polyimide substrate and laminate, and methods for producing them

The present invention relates to polyamic acid, polyamic acid solution, polyimide, polyimide substrate and laminate, and methods for producing them.

Electronic devices such as displays, touch panels, and solar cells are required to be thinner, lighter, and more flexible, and resin film substrates are being used instead of glass substrates.

In these devices, various electronic elements, such as thin film transistors and transparent electrodes, are formed on the substrate, and high-temperature processes are required to form these electronic elements. General aromatic polyimide has sufficient heat resistance to adapt to high-temperature processes, and its coefficient of linear thermal expansion (CTE) is also close to that of glass substrates and electronic elements. substrate material.

Aromatic polyimides are generally colored yellowish brown due to the formation of intramolecular conjugation and charge transfer (CT) complexes. In top-emission type organic EL devices, light is taken out from the side opposite to the substrate side, and the substrate is not required to be transparent, so a general aromatic polyimide has been used. However, in the case of transparent displays, bottom-emission type organic EL, and liquid crystal displays, where the light emitted from the display element is emitted through the substrate, and in order to make smartphones and the like full-screen displays (notchless) When the sensor and camera module are arranged on the back side of the substrate, the substrate is also required to have high optical properties.

Against this background, there is a demand for a material that has the same heat resistance as existing aromatic polyimides and also has excellent transparency.

It has been reported that the formation of a CT complex can be suppressed by using an aliphatic monomer in order to reduce the coloring of polyimide (Patent Documents 1 and 2). In addition, although it does not relate to a technique for reducing the coloring of polyimide, by imidizing polyamic acid as a polyimide precursor by adding silicone oil, the obtained polyimide film exhibits high adhesion to the substrate. is known (Patent Document 3).

Japanese Patent Application Laid-Open No. 2012-041530 Japanese Patent No. 5660249 Japanese Patent Application Laid-Open No. 2015-229691

However, the above conventional technology still has room for improvement in that it has high heat resistance and excellent transparency. Although the polyimides described in Patent Documents 1 and 2 have high transparency and low CTE, they have an aliphatic structure and thus have a low thermal decomposition temperature and cannot be applied to high-temperature processes for forming electronic devices.

In addition, organic EL light-emitting elements have low moisture resistance, and moisture entering from the outside causes dark spots, leakage current, and non-lighting. If a resin is used as the substrate, it is not possible to block moisture completely. Therefore, in order to improve the barrier property of the substrate, an inorganic film such as a silicon oxide film and a silicon nitride film is used as an intermediate layer between the polyimide layers of the two-layered polyimide film, or in the two-layered polyimide film. used on membranes. However, the adhesion of the inorganic film to the polyimide film is low, and there is a problem that peeling or lifting occurs at the interface between the inorganic film and the polyimide film during the process.

In view of the above, the present invention provides a polyimide having high heat resistance and high transparency and improved adhesion to an inorganic film, polyamic acid as a precursor thereof, a polyimide substrate and laminate, and methods for producing the same. for the purpose of providing

The inventors of the present application have found that by introducing a rigid structure into the polymer skeleton and further using a monomer component having a siloxane bond in combination, a polyimide satisfying the above properties and a polyamic acid as its precursor can be obtained. Found it. One embodiment of the present invention has the following configuration.

A polyamic acid that is a polyaddition reaction product of a diamine and a tetracarboxylic dianhydride, wherein the diamine comprises 1,4-phenylenediamine and 1,3-bis(3-aminopropyl)tetramethyldisiloxane , a polyamic acid in which said tetracarboxylic dianhydride comprises 3,3,4,4-biphenyltetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluoric dianhydride.

The present invention can provide polyimide having high heat resistance and high transparency and improved adhesion to inorganic films, and polyamic acid as its precursor. These are suitable as substrate materials for electronic devices.

A polyamic acid according to one embodiment of the present invention is a polyamic acid that is a polyaddition reaction product of a diamine and a tetracarboxylic dianhydride, wherein the diamine is 1,4-phenylenediamine and 1,3-bis (3-aminopropyl)tetramethyldisiloxane, wherein the tetracarboxylic dianhydride is 3,3,4,4-biphenyltetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxy It is a polyamic acid containing phenyl)fluoric acid dianhydride.

The polyimide obtained from the polyamic acid according to the present embodiment has a siloxane bond in the resin, which increases affinity with inorganic films (for example, silicon oxide films), and is expected to improve adhesion to inorganic films. On the other hand, if the repeating unit of the siloxane bond becomes longer, the glass transition temperature (Tg) of the resin will drop significantly, the heat resistance will drop due to the generation of cyclic siloxane due to intramolecular condensation, etc., and the facility will be contaminated. Therefore, the smaller the repeating unit of the siloxane bond, the better. Specifically, by using 1,3-bis(3-aminopropyl)tetramethyldisiloxane, it is possible to obtain a polyimide having high adhesion to inorganic films and high heat resistance. From the viewpoint of compatibility between adhesion and heat resistance, the ratio of 1,3-bis(3-aminopropyl)tetramethyldisiloxane when the total of all diamines is 100 mol% is 0.1 mol% to 10.0 mol%. is preferably 0.15 mol % to 1.0 mol %, and even more preferably 0.2 mol % to 0.5 mol %. Within the above range, the polyimide obtained from the polyamic acid can have sufficient adhesion to an inorganic film (for example, a silicon oxide film) and heat resistance capable of coping with high-temperature processes.

In order to obtain polyimide with low internal stress, the polyamic acid has a ratio of 3,3,4,4-biphenyltetracarboxylic dianhydride of 70 mol% with respect to a total of 100 mol% of all tetracarboxylic dianhydride. Polyamic acid is preferably ~99 mol%, more preferably 75 mol% to 98 mol%, more preferably 75 mol% to 97 mol%, more preferably 75 mol% to 96 mol%, more preferably 75 mol % to 95 mol %, more preferably 80 mol % to 90 mol %.

Owing to its bulky structure, 9,9-bis(3,4-dicarboxyphenyl)fluoric acid dianhydride suppresses the formation of a charge transfer complex, so that the polyimide obtained from the polyamic acid exhibits transparency. effective for On the other hand, since this bulky structure inhibits packing of molecular chains, the internal stress of the polyimide obtained from the polyamic acid tends to increase. Therefore, from the viewpoint of compatibility between transparency and moderate internal stress, the polyamic acid is 9,9-bis(3,4-dicarboxy Phenyl)fluoric acid dianhydride is preferably a polyamic acid having a proportion of 1 mol% to 30 mol%, more preferably 5 mol% to 25 mol%, and even more preferably 10 mol% to 20 mol%. Within the above range, the polyimide obtained from the polyamic acid can suppress an increase in internal stress, and can reduce the internal stress generated when laminated with a glass substrate or the like. Therefore, it is possible to obtain a material excellent in process compatibility without warping of the laminate in the manufacturing process of the laminate using the polyimide obtained from the polyamic acid or the electronic device using the laminate.

The polyamic acid according to the present embodiment is other than 1,4-phenylenediamine and other diamine components than 1,3-bis(3-aminopropyl)tetramethyldisiloxane as long as it does not impair its performance. may include Examples of other diamine components include 1,4-diaminocyclohexane, 1,3-phenylenediamine, 4,4'-oxydianiline, 3,4'-oxydianiline, 2,2'-bis(tri fluoromethyl)-4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-diaminobenzanilide, N,N'-bis(4-aminophenyl)terephthalamide, 4 , 4′-diaminodiphenylsulfone, 4-(aminophenyl) 4-aminobenzoate, m-tolidine, o-tolidine, 4,4′-bis(aminophenoxy)biphenyl, 2-(4-aminophenyl)-6- aminobenzoxazole, 3,5-diaminobenzoic acid, 4,4'-diamino-3,3'dihydroxybiphenyl, 4,4'-methylenebis(cyclohexanamine) and analogs thereof, which may be used alone. or two or more of them may be used in combination. Among them, 4-(aminophenyl) 4-aminobenzoate and the like are desirable from the viewpoint of improving Tg and transparency.

The polyamic acid according to the present embodiment is other than 3,3,4,4-biphenyltetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxy Other acid dianhydride components other than phenyl)fluoric acid dianhydride may also be included. Examples of the other acid dianhydride components include pyromellitic dianhydride, 1,4-phenylenebis(trimellitate dianhydride), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2′,3,3′-biphenyltetracarboxylic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride product, 4,4'-oxyphthalic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, dicyclohexyl-3,3',4,4'-tetracarboxylic dianhydride, 1, 2,4,5-cyclohexanetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, 2'-oxodispiro[bicyclo[2.2.1]heptane-2,1'-cyclopentane-3',2''-bicyclo[2.2.1]heptane]-5,6:5'',6''-tetracarboxylic dianhydrides and analogs thereof, which may be used alone, Alternatively, two or more kinds may be used in combination.

[Synthesis of polyamic acid and polyimide]
A polyimide containing the above structure can be obtained by a known method. A polyimide can be synthesized by a synthesis method involving precursors such as polyamic acid and polyimide ester, and a synthesis method not involving precursors. From the viewpoint of availability of monomers and ease of polymerization, it is preferable to synthesize polyimide by imidization of polyamic acid as a precursor.

A polyamic acid containing the above structure can be obtained by reacting a diamine and a tetracarboxylic dianhydride in an organic solvent. For example, a diamine is dissolved or dispersed in an organic solvent in the form of a slurry to obtain a diamine solution, and a tetracarboxylic dianhydride is dissolved in an organic solvent or dispersed in the form of a slurry in a solution or a solid state, and the diamine It may be added into the solution. A diamine may be added to the tetracarboxylic dianhydride solution. The dissolution and reaction of diamine and tetracarboxylic dianhydride are preferably carried out in an inert gas atmosphere such as argon or nitrogen.

In the synthesis of the polyamic acid, it is preferable to adjust the number of moles of the total amount of the diamine component and the number of moles of the total amount of the tetracarboxylic dianhydride component to be substantially the same. A polyamic acid having a plurality of constitutional units can be obtained by using a plurality of kinds of diamines and/or a plurality of kinds of tetracarboxylic dianhydrides. Also, by blending polyamic acids with different structures, it is possible to obtain a blend of polyamic acids having a plurality of structural units with different structures.

The organic solvent used for the polyamic acid synthesis reaction is not particularly limited. The organic solvent is preferably capable of dissolving the tetracarboxylic dianhydride and diamines used, and capable of dissolving polyamic acid produced by polymerization. Specific examples of the organic solvent include urea-based solvents such as tetramethylurea and N,N-dimethylethylurea; sulfoxide or sulfone-based solvents such as dimethylsulfoxide, diphenylsulfone, and tetramethylsulfone; N,N-dimethylacetamide ( DMAC), N,N-dimethylformamide (DMF), N,N'-diethylacetamide, N-methyl-2-pyrrolidone (NMP) and other amide solvents; γ-butyrolactone and other ester solvents; hexamethylphosphoric acid Amide solvents such as triamide; Halogenated alkyl solvents such as chloroform and methylene chloride; Aromatic hydrocarbon solvents such as benzene and toluene; Phenol solvents such as phenol and cresol; Ketone solvents such as cyclopentanone; , 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether and p-cresol methyl ether. Two or more organic solvents may be used in combination if necessary. In order to increase the solubility and reactivity of the polyamic acid, the organic solvent used in synthesizing the polyamic acid is preferably selected from amide solvents, ketone solvents, ester solvents and ether solvents, particularly DMF, Amide solvents such as DMAC and NMP are preferred.

The temperature conditions for the polyamic acid synthesis reaction are not particularly limited. From the viewpoint of suppressing a decrease in the molecular weight of the polyamic acid due to depolymerization, the reaction temperature is preferably 80° C. or lower. From the viewpoint of moderate progress of the polymerization reaction, the reaction temperature is more preferably 0 to 50°C. The reaction time may be arbitrarily set within the range of 10 minutes to 30 hours.

A polyamic acid solution containing polyamic acid and an organic solvent is obtained by polymerizing the diamine and the tetracarboxylic dianhydride in the organic solvent. This polymerization solution can be used as it is as a polyamic acid solution. Also, the concentration of polyamic acid and the viscosity of the solution may be adjusted by removing part of the solvent from the polymerization solution or by adding a solvent. The solvent to be added may be different from the solvent used for polymerizing the polyamic acid. Alternatively, a solid polyamic acid resin obtained by removing the solvent from the polymerization solution may be dissolved in a solvent to prepare a polyamic acid solution. As the organic solvent for the polyamic acid solution, one having a high solubility of polyamic acid is preferable, and the organic solvents exemplified above can be used as the organic solvent used for synthesizing the polyamic acid. Among them, amide solvents such as DMF, DMAC and NMP are preferred.

The imidization is carried out by dehydrating and ring-closing the polyamic acid. Dehydration ring closure is accomplished by azeotropic methods using azeotropic solvents, thermal methods or chemical methods. When imidization is performed in the state of solution, it is preferable to add an imidization agent and/or a dehydration catalyst to the polyamic acid solution to perform chemical imidization. Although the imidizing agent is not particularly limited, it is preferable to use a tertiary amine, and among them, a heterocyclic tertiary amine is more preferable. Examples of the heterocyclic tertiary amines include pyridine, picoline, quinoline, isoquinoline, and imidazoles. Examples of the dehydration catalyst include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, trifluoroacetic anhydride, and γ-valerolactone.

When imidization is carried out by removing the solvent from the polyamic acid solution, thermal imidization, in which dehydration ring closure is performed by heating, is preferable. The method of heating the polyamic acid is not particularly limited. Heat treatment may be performed. The heating time varies depending on the amount of the polyamic acid solution to be treated for dehydration ring closure and the heating temperature, but generally, it is preferable to perform heating for 1 minute to 5 hours after the treatment temperature reaches the maximum temperature. An imidization agent and/or a dehydration catalyst may be added to the polyamic acid solution, and imidization may be performed by heating in the above manner.

When the polyamic acid is thermally imidized, the imidization reaction and the decomposition of the polyamic acid occur at the same time. Obtainable. Examples of the method for suppressing the decomposition of the polyamic acid include esterification of the polyamic acid, silyl esterification, and increasing the reaction rate, but any method may be used. Specifically, by adding a small amount of tertiary amines such as imidazoles, the imidization rate during thermal imidization can be accelerated and a polyimide film with excellent transparency can be obtained. Examples of the imidazoles include 1H-imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1-phenylimidazole, 2 -phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole and the like. Among them, 1,2-dimethylimidazole is preferred.

The content of imidazoles in the polyamic acid solution is preferably 0.005 mol to 0.100 mol, more preferably 0.010 mol to 0.080 mol, and 0.015 mol to 0, per 1.000 mol of the amide group of the polyamic acid. 0.050 mol is more preferred. “Amido group of polyamic acid” means an amide group produced by polyaddition reaction of diamine and tetracarboxylic dianhydride. If the added amount of the imidazole is within the above range, improvement in transparency and low internal stress of the polyimide film can be expected.

When adding the imidazoles, it is preferable to add them after the polyamic acid is polymerized. The imidazole may be added to the polyamic acid solution as it is, or may be added to the polyamic acid solution as an imidazole solution.

The imidization of the polyamic acid into polyimide can be performed at any imidization rate of 1% to 100%, and a partially imidized polyamic acid may be synthesized. As the imidization of polyamic acid to polyimide proceeds, the solubility in organic solvents and the viscosity of the solution tend to change. Also, it is generally not easy to stop imidization at a specific imidization rate. When forming a film by applying and drying a solution, the viscosity and thixotropy of the solution affect the uniformity of the film thickness. Therefore, considering the stability of the process, the polyamic acid solution is applied onto the support while the imidization rate is 0% without adding an imidizing agent and a dehydration catalyst to the polyamic acid. Solvent removal and imidization are preferably carried out by heating on the support.

[Applications of polyamic acid and polyimide]
The polyamic acid and polyimide according to one embodiment of the present invention may be used as they are for producing products and members. Alternatively, a thermosetting component, a photocurable component, a non-polymerizable binder resin, a dye, a surfactant, a leveling agent, a plasticizer, a silane coupling agent, fine particles, a sensitizer, etc. are added to the polyamic acid and the polyimide. It may be added to form a composition. The mixing ratio of these optional components is preferably in the range of 0.1% by weight to 95% by weight with respect to the total solid content of the polyimide. The solid content of the composition is all components other than the organic solvent, and liquid monomer components are also included in the solid content.

Since the polyimide according to one embodiment of the present invention has excellent transparency and heat resistance, it can be used as a transparent substrate such as a substitute for glass. I can expect it. Among the electronic devices, it is preferably used as a substrate for devices requiring optical transparency, such as liquid crystal display devices, organic EL elements, electronic paper, and touch panels. The polyimide according to one embodiment of the present invention can also be used as a color filter, an antireflection film, an optical member such as a hologram, a building material, and a structural material. Various inorganic thin films such as metal oxides and transparent electrodes may be formed on the surface of the polyimide according to one embodiment of the present invention. The inorganic thin film is formed by, for example, a sputtering method, a PVD method such as a vacuum deposition method and an ion plating method, and a dry process such as a CVD method.

[Production of polyimide substrate and electronic device]
The polyimide according to one embodiment of the present invention is preferably used as a substrate of an electronic device manufactured by a batch process because it has good adhesion to a support in addition to heat resistance and transparency. In the batch process, a polyimide film (substrate) is formed on a support, electrodes and/or electronic elements are formed thereon, and then the polyimide substrate on which the electrodes and/or electronic elements are formed is peeled off from the support. An electronic device is obtained by

Therefore, in one embodiment of the present invention, there are provided a polyimide substrate made of the polyimide described above, a laminate of the polyimide substrate and a support, and an electronic device comprising electrodes and/or electronic elements on the polyimide substrate described above. Devices are also included. Further, in one embodiment of the present invention, there is provided a method for producing a laminate of a polyimide substrate and a support, wherein the polyamic acid solution is cast on the support and imidized to form a polyimide on the support. Also included is a method of manufacturing a laminate in which a polyimide substrate is formed in the substrate.

The thickness of the polyimide substrate is about 1-200 μm, preferably about 5-100 μm.

In one embodiment of the present invention, in order to improve the barrier properties of the polyimide substrate, an inorganic film such as a silicon oxide film and a silicon nitride film is formed as an intermediate layer between each polyimide layer of a two-layered polyimide film, or , can be used on a bilayered polyimide membrane.

As a specific example, for example, the polyamic acid solution is applied on a support, dried by heating and imidized, and then the polyimide film formed on the support is subjected to CVD vapor deposition of an inorganic film. conduct. Subsequently, the polyamic acid solution is applied again on the inorganic film, dried by heating, and imidized to obtain a polyimide film (polyimide substrate) adhered and laminated on the support. This example is an example of a polyimide substrate in which an inorganic film is used as an intermediate layer between polyimide layers of a two-layered polyimide film.

Examples of the support on which the polyamic acid solution is applied include glass substrates (glass plates); metal substrates such as SUS or metal belts; resin films such as polyethylene terephthalate, polycarbonate, polyacrylate, polyethylene naphthalate, and triacetyl cellulose. be done. In order to accommodate current batch-type device manufacturing processes, it is more preferable to use a glass substrate (glass plate) as the support.

When the polyamic acid solution is applied to the support such as glass and heated, the imidization of the polyamic acid begins as the solvent evaporates, and the organic solvent and the water generated by imidization (dehydration of the polyamic acid) are released from the polyamic acid solution. volatilize. At this time, part of the water and/or the organic solvent does not volatilize and stays between the support and the resin film during imidization, causing peeling at the interface between the support and the resin film. cause. The water and/or organic solvent remaining at the interface between the support and the resin film is then discharged through the polyimide film in the step of heating at a high temperature, and air bubbles remain in the portion where peeling or floating occurs. do. The generation of such air bubbles causes problems when forming elements on the polyimide substrate. In particular, in thinned or miniaturized devices, even minute peeling or floating has a great influence on the formation or mounting of elements.

Polyamic acid and polyimide according to one embodiment of the present invention having a siloxane structure, in addition to adhesion to glass, has high adhesion to an inorganic film used as an intermediate layer or the like. At the time of imidization, lifting and peeling due to retention of an organic solvent or water at the interface between the glass support and the resin film are less likely to occur. Therefore, it is possible to accurately form and mount elements on the polyimide substrate that is closely laminated on the support.

A polyimide film created using a polyamic acid solution according to an embodiment of the present invention can improve adhesion to an inorganic film in addition to high heat resistance and high transparency.

The polyimide film (polyimide substrate) adhered and laminated on the support preferably has a 90° peel strength from the support of 0.08 N/cm to 5.00 N/cm, more preferably 0.09 N/cm. It is more preferably ~4.00 N/cm, and even more preferably 0.10 N/cm ~ 3.50 N/cm. When the polyimide film (polyimide substrate) adhered and laminated on the support has the above-described adhesiveness, separation from the support is unlikely to occur in the element formation and mounting process, and the Easy to peel off from the support. The 90° peel strength can be measured by the method described in Examples below.

The transparency of the polyimide or the polyimide film is required to have a high transmittance in the entire wavelength range of visible light in applications such as displays. The yellowness index (YI) of the polyimide or the polyimide film is preferably 20 or less, more preferably 18 or less. YI can be measured according to JIS K7373-2006. A polyimide film having such high transparency can be used as a transparent substrate such as a substitute for glass.

The internal stress generated between the polyimide substrate and the support is preferably 30 MPa or less, preferably 25 MPa or less, and more preferably 20 MPa or less. The internal stress generated between the polyimide substrate and the support can be measured by the method described in Examples below. When the internal stress is 30 MPa or less, the laminate does not warp during the manufacturing process of the electronic device, so that the polyimide substrate has an advantage of being excellent in process adaptability.

An embodiment of the present invention may have the following configuration.

1). A polyamic acid that is a polyaddition reaction product of a diamine and a tetracarboxylic dianhydride, wherein the diamine comprises 1,4-phenylenediamine and 1,3-bis(3-aminopropyl)tetramethyldisiloxane , a polyamic acid in which said tetracarboxylic dianhydride comprises 3,3,4,4-biphenyltetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluoric dianhydride.

2). The polyamic acid according to 1), wherein the ratio of 1,3-bis(3-aminopropyl)tetramethyldisiloxane to the total amount of diamine is 0.1 mol% to 10.0 mol%.

3). The polyamic acid according to 1) or 2), wherein the ratio of 3,3,4,4-biphenyltetracarboxylic dianhydride to the total amount of tetracarboxylic dianhydride is 70 mol% to 99 mol%.

4). A polyamic acid solution containing the polyamic acid according to any one of 1) to 3) and an organic solvent.

5). The polyamic acid solution according to 4), further containing imidazoles.

6). The polyamic acid solution according to 5), wherein the imidazole content is 0.10 mol or less per 1 mol of the amide group of the polyamic acid.

7). 4) A polyimide which is an imidized product of the polyamic acid solution according to any one of 4) to 6).

8). 7) The polyimide according to 7), which has a yellowness index (YI) of 20 or less when the film thickness is 10 μm.

9). A method for producing a laminate of a polyimide substrate and a support, wherein the polyamic acid solution according to any one of 4) to 6) is cast on the support and imidized, thereby forming the polyamic acid solution on the support. A method for manufacturing a laminate, comprising forming a polyimide substrate.

10). A laminate of a polyimide substrate made of the polyimide according to 7) or 8) and a support.

11). The laminate according to 10), wherein the internal stress generated between the polyimide substrate and the support is 30 MPa or less.

12). An electronic device comprising electrodes and/or electronic elements on the polyimide substrate according to 10) or 11).

The present invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. is also included in the technical scope of the present invention.

(Evaluation method)
The material property values and the like described in this specification are obtained by the following methods.

(1) Peel strength A laminate of a glass plate (non-alkali glass) and a polyimide film, and a laminate of a glass plate and a polyimide film on which a silicon oxide film (inorganic film) is formed, according to the ASTM D1876-01 standard. , 90° peel strength from a glass plate and a glass plate on which a silicon oxide film (inorganic film) was formed were measured. A cut of 10 mm width is made in the polyimide film with a cutter knife, and a tensile tester (Strograph VES1D) manufactured by Toyo Seiki Co., Ltd. is used, under conditions of 23 ° C. and 55% RH, a tensile speed of 50 mm / min, a peel length of 50 mm and a peel length of 90. A peel test was carried out, and the average value of the peel strength was taken as the peel strength.

Here, the laminate of the glass plate (non-alkali glass) and the polyimide film was produced in the same manner as in [Preparation of polyimide film] described later. Further, the laminate of the glass plate on which the silicon oxide film (inorganic film) is formed and the polyimide film is described later [ Preparation of Polyimide Film]. The glass plate on which the silicon oxide film (inorganic film) was formed was produced by CVD vapor deposition of the silicon oxide film on the glass plate.

(2) Measurement of internal stress The polyamic acid solution prepared in the examples and comparative examples was applied with a spin coater on Corning non-alkali glass (thickness 0.7 mm, 100 mm × 100 mm) whose amount of warpage had been measured in advance. The polyamic acid solution-coated glass plate was baked in the air at 120° C. for 30 minutes and in a nitrogen atmosphere at 430° C. for 30 minutes to obtain a laminate of the glass substrate and the polyimide film having a thickness of 10 μm. rice field. The amount of warpage of the laminated body of the glass substrate and the polyimide film was measured using a thin film stress measuring device FLX-2320-S manufactured by Tencor Corporation, and the warpage occurred between the glass substrate and the polyimide film at 25 ° C. in a nitrogen atmosphere. The internal stress was evaluated. In order to avoid water absorption of the polyimide film, the laminate of the glass substrate and the polyimide film was measured immediately after baking or after being dried at 120° C. for 10 minutes.

(3) 1% weight loss temperature (TD1)
Using TG/DTA/7200 manufactured by Hitachi High-Tech Science Co., Ltd., the polyimide film was heated from 25° C. to 650° C. at a rate of 20° C./min under an N ₂ atmosphere. Considering the influence of moisture, the weight of the polyimide film at 150° C. was used as a reference, and the temperature at which the weight decreased by 1% was defined as TD1 of the polyimide film.

(4) Yellowness index (YI) of polyimide film
Using a UV-visible near-infrared spectrophotometer (V-650) manufactured by JASCO Corporation, the light transmittance of the polyimide film at 200-800 nm is measured, and from the formula described in JIS K 7373, yellow is used as an indicator of yellowness. An index (YI) was calculated.

(5) Appearance after heating test (high-temperature film formation process stability)
The polyamic acid solutions prepared in Examples and Comparative Examples were applied on Corning non-alkali glass (thickness 0.7 mm, 100 mm × 100 mm) with a spin coater, and the glass substrate coated with the polyamic acid solution was exposed to air. It was baked at 120° C. for 30 minutes in the atmosphere and at 430° C. for 30 minutes in a nitrogen atmosphere to obtain a laminate of the glass substrate and the polyimide film having a thickness of 10 μm. 1 μm of SiOx is laminated on the polyimide film of this laminate by the PE-CVD method, and the laminate is heated from room temperature to 470° C. at 5° C./min in a nitrogen atmosphere. After baking by holding for a minute, it was visually confirmed whether there was any floating between the SiOx or glass substrate and the polyimide film. ○ (good) if there is no float, △ (normal) if there are 1 or more but less than 5 floats, × (bad) if there are 5 or more, and × if the film is damaged due to thermal decomposition x (very bad).

[Preparation of polyamic acid solution]
<Example 1>
In a 300 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring blade and a nitrogen inlet tube, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) 8.68 g, 9, 2.55 g of 9-bis(3,4-dicarboxyphenyl)fluoric acid dianhydride (BPAF) and 85.0 g of N-methyl-2-pyrrolidone (NMP) were charged and stirred at room temperature (23° C.). Dissolved. After 30 minutes, 0.009 g of 1,3-bis(3-aminopropyl)tetramethyldisiloxane (PAM-E) was added to the resulting solution and stirred. 3.76 g of 1,4-phenylenediamine (PDA) was added to this solution and stirred at room temperature for 5 hours to obtain a polyamic acid solution. The concentration of diamine and tetracarboxylic dianhydride charged in this reaction solution was 15% by weight with respect to the total amount of the reaction solution. Further, 1,2-dimethylimidazole (DMI) was added to and dissolved in this solution so as to be 1% by weight with respect to polyamic acid (resin content).

<Example 2>
The procedure of Example 1 was repeated except that the amount of BPDA charged was changed to 8.68 g, the amount of BPAF charged was changed to 2.55 g, the amount of PAM-E charged was changed to 0.013 g, and the amount of PDA charged was changed to 3.76 g. to obtain a polyamic acid solution.

<Example 3>
The procedure of Example 1 was repeated except that the amount of BPDA charged was changed to 8.68 g, the amount of BPAF charged was changed to 2.55 g, the amount of PAM-E charged was changed to 0.017 g, and the amount of PDA charged was changed to 3.76 g. to obtain a polyamic acid solution.

<Example 4>
The procedure of Example 1 was repeated except that the amount of BPDA charged was changed to 8.69 g, the amount of BPAF charged was changed to 2.55 g, the amount of PAM-E charged was changed to 0.026 g, and the amount of PDA charged was changed to 3.74 g. to obtain a polyamic acid solution.

<Example 5>
The procedure of Example 1 was repeated except that the amount of BPDA charged was changed to 8.68 g, the amount of BPAF charged was changed to 2.55 g, the amount of PAM-E charged was changed to 0.043 g, and the amount of PDA charged was changed to 3.73 g. to obtain a polyamic acid solution.

<Example 6>
The procedure of Example 1 was repeated except that the amount of BPDA charged was changed to 8.67 g, the amount of BPAF charged was changed to 2.54 g, the amount of PAM-E charged was changed to 0.086 g, and the amount of PDA charged was changed to 3.70 g. to obtain a polyamic acid solution.

<Example 7>
The charged amount of BPDA was changed to 10.085 g, the charged amount of BPAF was changed to 0.993 g, the charged amount of PAM-E was changed to 0.018 g, and the charged amount of PDA was changed to 3.904 g, and 1,2-dimethylimidazole was added. A polyamic acid solution was obtained in the same manner as in Example 1, except that there was no polyamic acid.

<Example 8>
The same procedure as in Example 7 was repeated except that the amount of BPDA charged was changed to 9.370 g, the amount of BPAF charged to 1.784 g, the amount of PAM-E charged to 0.018 g, and the amount of PDA charged to 3.829 g. to obtain a polyamic acid solution.

<Example 9>
The same procedure as in Example 1 was repeated except that the amount of BPDA charged was changed to 9.366 g, the amount of BPAF charged to 1.784 g, the amount of PAM-E charged to 0.026 g, and the amount of PDA charged to 3.823 g. to obtain a polyamic acid solution.

<Example 10>
The procedure of Example 7 was repeated except that the amount of BPDA charged was changed to 8.681 g, the amount of BPAF charged was changed to 2.546 g, the amount of PAM-E charged was changed to 0.017 g, and the amount of PDA charged was changed to 3.756 g. to obtain a polyamic acid solution.

<Example 11>
The same procedure as in Example 7 was repeated except that the amount of BPDA charged was changed to 8.629 g, the amount of BPAF charged was changed to 2.551 g, the amount of PAM-E charged was changed to 0.043 g, and the amount of PDA charged was changed to 3.766 g. to obtain a polyamic acid solution.

<Example 12>
The same procedure as in Example 7 was repeated except that the amount of BPDA charged was changed to 8.018 g, the amount of BPAF charged to 3.279 g, the amount of PAM-E charged to 0.017 g, and the amount of PDA charged to 3.686 g. to obtain a polyamic acid solution.

<Example 13>
The same procedure as in Example 1 was repeated except that the amount of BPDA charged was changed to 8.015 g, the amount of BPAF charged was changed to 3.278 g, the amount of PAM-E charged was changed to 0.025 g, and the amount of PDA charged was changed to 3.681 g. to obtain a polyamic acid solution.

<Example 14>
The procedure of Example 1 was repeated except that the amount of BPDA charged was changed to 7.543 g, the amount of BPAF charged was changed to 3.871 g, the amount of PAM-E charged was changed to 0.025 g, and the amount of PDA charged was changed to 3.651 g. to obtain a polyamic acid solution.

<Example 15>
The procedure of Example 1 was repeated except that the amount of BPDA charged was changed to 8.587 g, the amount of BPAF charged was changed to 2.549 g, the amount of PAM-E charged was changed to 0.173 g, and the amount of PDA charged was changed to 3.692 g. to obtain a polyamic acid solution.

<Example 16>
Polyamic acid was prepared in the same manner as in Example 1, except that the amount of BPDA charged was changed to 4.548 g, the amount of BPAF charged was changed to 7.087 g, the amount of PDA charged was changed to 3.342 g, and PAM-E was changed to 0.023 g. A solution was obtained.

<Comparative Example 1>
8.70 g of BPDA, 2.55 g of BPAF, and 85.0 g of NMP were charged into a 300 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring blade and a nitrogen inlet tube, and stirred at room temperature (23 ° C.) to dissolve. rice field. After 30 minutes had passed, 3.75 g of PDA was added to this solution and stirred at room temperature for 5 hours to obtain a polyamic acid solution. Further, 1,2-dimethylimidazole was added to and dissolved in this solution so as to be 1% by weight with respect to polyamic acid (resin content).

<Comparative Example 2>
The same as in Comparative Example 1 except that the amount of BPDA charged was changed to 9.478 g, the amount of BPAF charged was changed to 1.641 g, and the amount of PDA charged was changed to 3.881 g, and 1,2-dimethylimidazole was not added. to obtain a polyamic acid solution.

<Comparative Example 3>
The same as in Comparative Example 1 except that the amount of BPDA charged was changed to 8.107 g, the amount of BPAF charged was changed to 3.158 g, and the amount of PDA charged was changed to 3.734 g, and 1,2-dimethylimidazole was not added. to obtain a polyamic acid solution.

<Comparative Example 4>
A polyamic acid solution was prepared in the same manner as in Example 1, except that the amount of BPDA charged was changed to 10.950 g, the amount of BPAF charged to 0 g, the amount of PDA charged to 4.023 g, and the amount of PAM-E changed to 0.028 g. Obtained.

<Comparative Example 5>
The amount of BPDA charged was 8.643 g, the amount of BPAF charged was 2.565 g, the amount of PDA charged was 3.792 g, PAM-E was adjusted to 0 g, and 3-aminopropyltriethoxysilane (APS) was added to 0.2 g. A polyamic acid solution was obtained in the same manner as in Comparative Example 2, except that the addition amount was 05% by weight.

<Comparative Example 6>
A polyamic acid solution was obtained in the same manner as in Comparative Example 5, except that APS was added in an amount of 0.2% by weight.

<Comparative Example 7>
A polyamic acid solution was obtained in the same manner as in Comparative Example 5, except that APS was added in an amount of 0.3% by weight.

<Comparative Example 8>
4.166 g of trans-1,4-cyclohexanediamine (CHDA), 0.046 g of PAM-E and 85 g of NMP were charged into a 300 mL glass separable flask equipped with a stirrer equipped with stainless steel stirring blades and a nitrogen inlet tube, and the mixture was heated to room temperature. Dissolved by stirring at (23° C.). After 30 minutes, 10.788 g of BPDA was added, heated at 80° C. for 30 minutes, cooled to room temperature, and stirred for 5 hours to obtain a polyamic acid solution. Further, 1,2-dimethylimidazole was added to and dissolved in this solution so as to be 1% by weight with respect to polyamic acid (resin content).

[Preparation of polyimide film]
NMP was added to each of the polyamic acid solutions obtained in the above examples and comparative examples to dilute the polyamic acid concentration to 10.0% by weight. Using a spin coater, the diluted polyamic acid solution was cast on a 10 mm × 10 mm square non-alkali glass plate (Corning Eagle XG, thickness 0.7 mm) so that the thickness after drying was 10 μm. did. After drying the glass plate on which the diluted polyamic acid solution was cast in a hot air oven at 120° C. for 30 minutes, imidization was performed by heating at 430° C. for 30 minutes in a nitrogen atmosphere to form a polyimide film having a thickness of 10 μm. A laminate with the glass plate was obtained. The polyimide film was peeled off from the glass substrate of the obtained laminate, and the characteristics were evaluated.

Table 1 shows the composition of the polyamic acid solution of each example and comparative example, and the evaluation results of the polyimide film. The composition in Table 1 represents the total of tetracarboxylic dianhydride and diamine as 100 mol % (unit: mol %). The amount of 1,2-dimethylimidazole (DMI) added is the amount (unit: parts by weight) added to 100 parts by weight of polyamic acid (resin content). In the table, "Stress" represents internal stress generated between the polyimide film and the support. In addition, "-" in the table indicates that no measurement was performed.

　表１に示すように、ジアミンとテトラカルボン酸二無水物との重付加反応物であるポリアミド酸であって、前記ジアミンが、１，４－フェニレンジアミンおよび１，３－ビス（３－アミノプロピル）テトラメチルジシロキサンを含み、前記テトラカルボン酸二無水物が、３，３，４，４－ビフェニルテトラカルボン酸二無水物および９，９－ビス（３，４－ジカルボキシフェニル）フルオレン酸二無水物を含むポリアミド酸を用いる実施例１～１６では、得られたポリイミド膜は、以下に示す特性を有する。

As shown in Table 1, a polyamic acid that is a polyaddition reaction product of a diamine and a tetracarboxylic dianhydride, wherein the diamine is 1,4-phenylenediamine and 1,3-bis(3-aminopropyl ) tetramethyldisiloxane, wherein said tetracarboxylic dianhydride is 3,3,4,4-biphenyltetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluoric acid dianhydride For Examples 1-16 using polyamic acid containing anhydrides, the resulting polyimide films have the properties shown below.

- Adhesion to glass is 0.10 N/cm or more - Adhesion to _SiO2 is 0.05 N/cm or more - YI is 20 or less In addition, 3,000 mol% of all tetracarboxylic dianhydrides total 100 mol%. The ratio of 3′,4,4′-biphenyltetracarboxylic dianhydride is 70 to 99 mol%, and the ratio of 9,9-bis(3,4-dicarboxyphenyl)fluoric dianhydride is 1 to 30 mol%. Furthermore, by introducing 1,3-bis(3-aminopropyl)tetramethyldisiloxane into polyamic acid using 1,4-phenylenediamine as a diamine, the resulting polyimide film has the following characteristics. have.

・ Adhesion to glass is 0.10 N/cm or more ・ Adhesion to _SiO2 is 0.05 N/cm or more ・ Internal stress is 30 MPa or less ・ YI is 20 or less Total of all tetracarboxylic dianhydrides is 100 mol% On the other hand, the ratio of 3,3′,4,4′-biphenyltetracarboxylic dianhydride is 50 mol%, and the ratio of 9,9-bis(3,4-dicarboxyphenyl)fluoric dianhydride is 50 mol%. It was found that the polyimide film of Example 16 had excellent adhesion to glass and a silicon oxide film and had a small YI value, but had a higher internal stress than those of other Examples.

The polyimide films of Comparative Examples 1 to 3, which do not use 1,3-bis(3-aminopropyl)tetramethyldisiloxane as a monomer, have low internal stress and high transparency, but have poor adhesion to glass and silicon oxide films. It was small, and many floats occurred between the SiOx or glass substrate and the polyimide film after the heating test.

The polyimide film of Comparative Example 4, which does not use 9,9-bis(3,4-dicarboxyphenyl)fluoric acid dianhydride as a monomer, has excellent adhesion to glass and silicon oxide films, and SiOx or There is no floating between the glass substrate and the polyimide film, and the internal stress is small, but the YI value is large and the transparency is low.

The polyimide film of Comparative Example 5 containing 0.05 phr of 3-aminopropyltriethoxysilane (APS) without using 1,3-bis(3-aminopropyl)tetramethyldisiloxane as a monomer has low internal stress and transparency. However, the adhesiveness to the glass and the silicon oxide film was low, and a large amount of floating occurred between the SiOx or glass substrate and the polyimide film after the heating test.

The polyimide films of Comparative Examples 6 and 7 containing 0.2 phr to 0.3 phr of 3-aminopropyltriethoxysilane (APS) without using 1,3-bis(3-aminopropyl)tetramethyldisiloxane as a monomer are Although the internal stress was low and the transparency was high, the adhesiveness to the silicon oxide film was low, and floating occurred between the SiOx or glass substrate and the polyimide film after the heating test.

The polyimide film of Comparative Example 8, which did not use 9,9-bis(3,4-dicarboxyphenyl)fluoric acid dianhydride as a monomer and used CHDA instead of PDA, was damaged by thermal decomposition after the heating test. Was.

From this result, 3,3′,4,4′-biphenyltetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluoric dianhydride according to one embodiment of the present invention, A polyimide obtained by introducing 1,3-bis(3-aminopropyl)tetramethyldisiloxane into a polyamic acid composed of 1,4-phenylenediamine has excellent heat resistance and adhesion to glass and silicon oxide films. was confirmed to be high and to be highly transparent.

In addition, the ratio of 3,3′,4,4′-biphenyltetracarboxylic dianhydride is 70 to 99 mol% with respect to the total 100 mol% of all tetracarboxylic dianhydrides, 9,9-bis(3,4 -dicarboxyphenyl)fluoric acid dianhydride is 1 to 30 mol%, and 1,3-bis(3-aminopropyl)tetramethyldisiloxane is added to polyamic acid using 1,4-phenylenediamine as a diamine. It was confirmed that the polyimide obtained by introducing has excellent heat resistance, high adhesion to glass and silicon oxide film, low internal stress with inorganic substrates, and high transparency.

The present invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. is also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

Claims (12)

A polyamic acid that is a polyaddition reaction product of a diamine and a tetracarboxylic dianhydride, wherein the diamine comprises 1,4-phenylenediamine and 1,3-bis(3-aminopropyl)tetramethyldisiloxane , a polyamic acid in which said tetracarboxylic dianhydride comprises 3,3,4,4-biphenyltetracarboxylic dianhydride and 9,9-bis(3,4-dicarboxyphenyl)fluoric dianhydride. The polyamic acid according to claim 1, wherein the ratio of 1,3-bis(3-aminopropyl)tetramethyldisiloxane to the total amount of diamine is 0.1 mol% to 10.0 mol%. The polyamic acid according to claim 1 or 2, wherein the ratio of 3,3,4,4-biphenyltetracarboxylic dianhydride to the total amount of tetracarboxylic dianhydride is 70 mol% to 99 mol%. A polyamic acid solution containing the polyamic acid according to any one of claims 1 to 3 and an organic solvent. The polyamic acid solution according to claim 4, further containing imidazoles. The polyamic acid solution according to claim 5, wherein the imidazole content is 0.10 mol or less per 1 mol of the amide group of the polyamic acid. A polyimide that is an imidized product of the polyamic acid solution according to any one of claims 4 to 6. The polyimide according to claim 7, which has a yellowness index (YI) of 20 or less when the film thickness is 10 µm. A method for producing a laminate of a polyimide substrate and a support,
A method for producing a laminate, comprising: forming a polyimide substrate on a support by casting the polyamic acid solution according to any one of claims 4 to 6 on a support and imidizing the solution. A laminate of a polyimide substrate made of the polyimide according to claim 7 or 8 and a support. The laminate according to claim 10, wherein the internal stress generated between the polyimide substrate and the support is 30 MPa or less. An electronic device comprising electrodes and/or electronic elements on the polyimide substrate according to claim 10 or 11.