JP6687442B2 - Utilization of polyamic acid, polyimide, polyamic acid solution, and polyimide - Google Patents

Description

  The present invention relates to polyamic acid, polyimide, and polyamic acid solution. The present invention further provides an electronic device material using polyimide, a TFT substrate, a flexible display substrate, a color filter, a printed matter, an optical material, a liquid crystal display device, an image display device such as an organic EL and electronic paper, a 3-D display, and a sun. The present invention relates to a substitute material for a portion where glass is currently used, such as a battery, a touch panel, and a transparent conductive film substrate.

  2. Description of the Related Art In recent years, with the rapid progress of displays such as liquid crystal, organic EL, and electronic paper, and electronics such as solar cells and touch panels, there has been a demand for thinner and lighter devices, and further for flexibility. Therefore, in place of the glass substrate used for these devices, a plastic film substrate which is thin, lightweight and flexible is being studied.

  In these devices, various electronic elements such as thin film transistors and transparent electrodes are formed on a substrate, and a high temperature process is required to form these electronic elements. Therefore, the plastic film substrate is required to have sufficient heat resistance so that it can be applied to a high temperature process. When these electronic elements made of an inorganic material are formed on a film, the film may warp after the formation of the inorganic element or the inorganic element may be destroyed due to the difference in the linear thermal expansion coefficient between the inorganic material and the film. I was afraid. Therefore, a material having a thermal expansion coefficient and a linear thermal expansion coefficient equivalent to that of an inorganic material has been desired.

  Further, when the light emitted from the display element (liquid crystal, organic EL, etc.) is emitted through the plastic film substrate (for example, bottom emission type organic EL, etc.), the plastic film substrate needs to be transparent. Become. In particular, it is required that the light transmittance be high in the wavelength region of 400 nm or less, which is the visible light region.

The fabrication process of these devices is divided into batch type and roll-to-roll type. When using a roll-to-roll fabrication process, new equipment is required and some problems due to rotation and contact must be overcome. On the other hand, the batch type is a process in which a coating resin solution is applied on a glass substrate, dried to form a substrate, and then peeled off. Therefore, the batch type is advantageous in terms of cost because it can utilize the glass substrate process equipment such as the current TFT.
However, in the batch type, if the adhesion between the glass substrate and the resin substrate formed on the glass substrate is poor, it may not be applicable to the manufacturing process.

From such a background, it is strongly desired to develop a material which can be applied to an existing batch process and has excellent heat resistance, low thermal expansion property, transparency, and excellent adhesion to an inorganic substrate such as glass.
As a material satisfying the above requirements, a polyimide-based material which is known to have excellent heat resistance has been studied. In order to obtain a polyimide having high transparency and low thermal expansion, a monomer having a rigid structure or an alicyclic monomer is generally used (Patent Documents 1 and 2). Further, it is known that the adhesion to an inorganic substrate is improved by using a silane coupling agent (Patent Document 3).

Japanese Patent Laid-Open Publication "Japanese Patent Application Laid-Open No. 2002-161136 (Published June 4, 2002)" Japanese Unexamined Patent Publication "JP 2012-41530 A (Published March 1, 2012)" Japanese Unexamined Patent Publication “JP-A-2014-9305 (Published January 20, 2014)”

  However, none of Patent Documents 1 to 3 describes a polyimide that is excellent in transparency, heat resistance, and low thermal expansion, and further has excellent adhesiveness to an inorganic substrate.

  The present invention has been accomplished in view of the above circumstances, heat resistance, low thermal expansion, a polyimide excellent in transparency, further showing adhesion to an inorganic substrate, and to obtain a polyamic acid as a precursor thereof. With the goal. Further, it is an object of the present invention to provide a product or member which is required to have high heat resistance and transparency by using the polyimide and polyamic acid. In particular, it is an object of the present invention to provide a product and a member in which the polyimide and the polyamic acid of the present invention are applied to the surface of an inorganic material such as glass, metal, metal oxide and single crystal silicon.

  As a result of intensive investigations for solving the above-mentioned problems, the present inventors have obtained heat-resistant, low thermal expansion, and excellent transparency, and further, to obtain a polyimide showing excellent adhesion with an inorganic substrate. Have found that it is effective to introduce a rigid structure and an alicyclic structure into the skeleton and to use a paraaromatic ester-encapsulating monomer in combination.

That is, the present invention relates to the following [1] to [17].
[1] A polyamic acid represented by the repeating unit of the general formula (1),
Among the structural units, A in the general formula, A contains (2) and (3), and B contains at least 50 mol% or more of (4), a polyamic acid.

  [2] At least 80 mol% or more of the structural unit A represented by (1) is occupied by (2) and (3), and the molar ratio represented by (2) / (3) is The polyamic acid according to [1], which is in the range of 99/1 to 1/99.

  [3] At least 80 mol% or more of the structural unit A represented by (1) is occupied by (2) and (3), and the molar ratio represented by (2) / (3) is The polyamic acid according to [2], which is in the range of 99/1 to 70/30.

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

  [5] A method for producing a polyimide, which is obtained by applying the polyamic acid solution according to [4] to a support.

  [6] A polyimide represented by the general formula (5),

Among the constitutional units, in the general formula, A contains (2) and (3), and B contains at least 50 mol% or more (4).

  [7] At least 80 mol% or more of the structural unit A represented by (5) is occupied by (2) and (3), and the molar ratio represented by (2) / (3) is The polyimide described in [6], which is in the range of 99/1 to 1/99.

  [8] At least 80 mol% or more of the structural unit A represented by (5) is occupied by (2) and (3), and the molar ratio represented by (2) / (3) is The polyimide described in [7], which is in the range of 99/1 to 70/30.

  [9] The polyimide according to any one of [6] to [8], which has a light transmittance of 50% or more at a wavelength of 400 nm when the film thickness is 10 to 15 μm.

  [10] The polyimide according to any one of [6] to [9], which has a thermal expansion coefficient of 20 ppm / K or less at 100 to 300 ° C. when the film thickness is 10 to 15 μm.

  [11] The polyimide according to any one of [6] to [10], which has a glass transition temperature of 300 ° C. or higher.

  [12] The polyimide according to any one of [6] to [11], which has a 90-degree peel strength of 0.03 N / cm or more with the inorganic layer.

  [13] The cut-off wavelength is 340 nm or more when the film thickness is 10 to 15 µm, and the polyimide according to any one of [6] to [12].

  [14] A substrate containing the polyimide according to any one of [6] to [13].

  [15] An optical material containing the polyimide according to any one of [6] to [13].

  [16] An image display device containing the polyimide according to any one of [6] to [13].

  [17] An electronic device containing the polyimide according to any one of [6] to [13].

  The polyimide produced by using the polyamic acid according to the present invention has heat resistance, low thermal expansion property, transparency, and adhesiveness with an inorganic substrate. Therefore, the polyimide according to the present invention and the polyamic acid according to the present invention are suitable as a film or a substrate for a member that is required to have heat resistance, low thermal expansion property, transparency, and adhesiveness with an inorganic substrate. Is.

  The present invention will be described in detail below, but the present invention is not limited thereto.

  The polyamic acid according to the present invention is a polyamic acid represented by the repeating unit of the general formula (1), and in the structural unit, A in the general formula includes (2) and (3), and B has at least Includes 50 mol% or more (4).

  From the viewpoint of low linear thermal expansion, B in the general formula (1) is preferably a trans form of 1,4-cyclohexanediamine residue. From the viewpoint of transparency, it is desirable that (4) is 50 mol% or more, preferably 70 mol% or more, and more preferably 90 mol% or more.

  Further, any diamine can be copolymerized as long as it does not affect the characteristics. For example, 1,4-phenylenediamine, 1,3-phenylenediamine, 4,4′-oxydianiline, 3,4′-oxydianiline, 4,4′-diaminobenzanilide, 4′-aminophenyl-4- Aminobenzene, N, N′-bis (4-aminophenyl) terephthalamide, 2,2′-bis (trifluoromethyl) benzidine, 4,4′-diaminodiphenylsulfone, 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), 1,3-bis (3-aminopropyl) tetramethyldisiloxane and the like Goods and the like, can be used alone or two or more kinds.

  From the viewpoint of low thermal expansion, A in the general formula (1) contains at least 80 mol% or more of the above (2) and (3), and from the viewpoint of adhesion to an inorganic substrate, the above (2) / the above (3) The molar ratio of () is preferably 99/1 to 1/99, more preferably 1/99 to 30/70, and further preferably 5/95 to 20/80.

  Further, any acid dianhydride can be copolymerized as long as it does not affect the characteristics. For example, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ', 3,3'- Biphenyl tetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxyphthalic dianhydride, 9,9-bis (3,4-dicarboxyphenyl ) Fluorenoic dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, dicyclohexyl-3,3', 4,4'-tetracarboxylic dianhydride, 1,2,4,5- Cyclohexanetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, 2'-oxodisspiro [2.2.1] heptane-2,1 ''-cycloheptane-3,2 ''-bicyclo [2. .1] heptane -5,5'-6,6'-tetracarboxylic acid dianhydride and the like thereof, with can be used alone or two or more kinds.

  In a batch type device manufacturing process of coating a polyamic acid solution on a support such as glass, heating it to imidize it, forming an electronic element or the like to form a substrate, and then peeling it off, It is necessary that the adhesion between them is good.

  The polyimide according to the present invention is a polyimide comprising a repeating unit represented by the general formula (5), in which A in the general formula includes (2) and (3), and at least 50 mol% in B in the general formula. Including (4) above.

  B in the general formula (5) is preferably a trans form of 1,4-cyclohexanediamine residue from the viewpoint of low linear thermal expansion. From the viewpoint of transparency, it is desirable that (4) is 50 mol% or more, preferably 70 mol% or more, and more preferably 90 mol% or more.

  Further, any diamine can be copolymerized as long as it does not affect the characteristics. For example, 1,4-phenylenediamine, 1,3-phenylenediamine, 4,4′-oxydianiline, 3,4′-oxydianiline, 4,4′-diaminobenzanilide, 4′-aminophenyl-4- Aminobenzene, N, N′-bis (4-aminophenyl) terephthalamide, 2,2′-bis (trifluoromethyl) benzidine, 4,4′-diaminodiphenylsulfone, 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), 1,3-bis (3-aminopropyl) tetramethyldisiloxane and the like Goods and the like, can be used alone or two or more kinds.

  A in the general formula (5) contains at least 80 mol% or more of the above (2) and (3) from the viewpoint of low thermal expansion, and from the viewpoint of adhesion to an inorganic substrate, (2) / (3) above. The molar ratio of () is preferably 99/1 to 1/99, more preferably 1/99 to 30/70, and further preferably 5/95 to 20/80.

  Further, any acid dianhydride can be copolymerized as long as it does not affect the characteristics. For example, pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ', 3,3'- Biphenyl tetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxyphthalic dianhydride, 9,9-bis (3,4-dicarboxyphenyl ) Fluorenoic dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, dicyclohexyl-3,3', 4,4'-tetracarboxylic dianhydride, 1,2,4,5- Cyclohexanetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, 2'-oxodisspiro [2.2.1] heptane-2,1 ''-cycloheptane-3,2 ''-bicyclo [2. .1] heptane -5,5'-6,6'-tetracarboxylic acid dianhydride and the like thereof, with can be used alone or two or more kinds.

  The polyimide of the present invention can be obtained by imidizing a polyamic acid containing a structural unit represented by the general formula (1). Further, the polyimide of the present invention may be synthesized from a generally known precursor such as polyamic acid ester or polyamic acid silyl ester, or may be produced without passing through the precursor.

  The polyamic acid of the present invention can be synthesized by a known general method, and can be obtained by reacting a diamine and a tetracarboxylic dianhydride in an organic solvent. Specifically, for example, the diamine is dissolved or dispersed in a slurry in an organic solvent in an inert atmosphere such as argon or nitrogen to prepare a diamine solution. On the other hand, the tetracarboxylic dianhydride may be added to the diamine solution after being dissolved in an organic solvent or dispersed in a slurry state or in a solid state.

  When synthesizing a polyamic acid using a diamine and a tetracarboxylic acid dianhydride, the number of moles of the diamine component total amount of one or more, and the number of moles of the tetracarboxylic acid dianhydride component total amount of one or more, substantially, A polyamic acid copolymer can be arbitrarily obtained by adjusting the molar ratio to be equimolar. It is also possible to obtain a polyamic acid containing a plurality of tetracarboxylic dianhydrides and diamines by blending two polyamic acids. The temperature condition of the reaction between the diamine and the tetracarboxylic dianhydride, that is, the synthesis reaction of the polyamic acid is not particularly limited. When an alicyclic diamine is used, salt formation often occurs, so the temperature of the polyamic acid synthesis reaction may be set in the range of 50 ° C. to 150 ° C. if necessary, and the salt dissolves and the polymerization reaction proceeds. Once started, the temperature of the polyamic acid synthesis reaction is preferably 80 ° C. or lower, and more preferably 0 ° C. or higher and 50 ° C. or lower, in order to suppress the decrease in the molecular weight of the polyamic acid. Further, the reaction time may be arbitrarily set within the range of 10 minutes to 30 hours.

  Furthermore, the organic solvent used in the synthesis reaction of the polyamic acid is not particularly limited as long as it is an organic polar solvent. As the reaction between the diamine and the tetracarboxylic dianhydride progresses, polyamic acid is produced, and the viscosity of the reaction solution increases.

  The organic solvent used for the polymerization of the polyamic acid is preferably one capable of dissolving the tetracarboxylic dianhydride and diamines used, and more preferably one capable of dissolving the polyamic acid produced. . The organic solvent used in the synthesis reaction of the polyamic acid is, for example, a urea-based solvent such as tetramethylurea or N, N-dimethylethylurea, a sulfoxide or a sulfone-based solvent such as dimethyl sulfoxide, diphenyl sulfone, or tetramethyl sulfone. , N, N-dimethylacetamide (DMAC), N, N-dimethylformamide (DMF), N, N′-diethylacetamide, N-methyl-2-pyrrolidone (NMP), ester solvents such as γ-butyrolactone, hexa, etc. Amide solvents such as methylphosphoric acid triamide, alkyl halide solvents such as chloroform and methylene chloride, aromatic hydrocarbon solvents such as benzene and toluene, phenol solvents such as phenol and cresol, and ketone solvents such as cyclopentanone. Solvent, tetrahydrofuran , 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether, ether solvents such as p- cresol methyl ether. Usually, these solvents are used alone, but if necessary, two or more kinds may be appropriately combined and used. In order to increase the solubility and reactivity of the polyamic acid, the organic solvent used in the synthesis reaction of the polyamic acid is preferably selected from an amide solvent, a ketone solvent, an ester solvent and an ether solvent, particularly Amide solvents such as DMF, DMAC and NMP are preferred.

  A method of imidizing the polyamic acid to obtain a polyimide using the polyamic acid will be described. The imidization is performed by dehydrating and ring-closing the polyamic acid. This dehydration ring closure can be carried out by an azeotropic method using an azeotropic solvent, a thermal method or a chemical method. Further, the imidation of polyamic acid to polyimide can be performed at an arbitrary ratio of 1 to 100%. That is, a polyamic acid partially imidized may be synthesized. In this specification, a solution containing a polyamic acid and an organic solvent is referred to as a polyamic acid solution. Here, as the organic solvent contained in the polyamic acid solution, the same organic solvent as the organic solvent used in the synthesis reaction of the polyamic acid can be used, and among them, an amide solvent, a ketone solvent, an ester solvent. And an organic solvent selected from ether solvents can be more preferably used, and amide solvents such as DMF, DMAC, and NMP can be particularly preferably used. When polyamic acid is obtained by the method described above, the synthesized reaction solution itself may be referred to as a polyamic acid solution.

  The dehydration ring closure may be performed by heating the polyamic acid. The method for heating the polyamic acid is not particularly limited, but for example, after casting or coating the polyamic acid solution on a support such as a glass plate, a metal plate, PET (polyethylene terephthalate), etc., within the range of 80 ° C to 500 ° C. The heat treatment may be performed in. Alternatively, dehydration ring closure of the polyamic acid can be performed by directly placing the polyamic acid solution in a container that has been subjected to a mold release treatment such as coating with a fluororesin and heating and drying the polyamic acid solution under reduced pressure. A polyimide can be obtained by dehydration ring closure of a polyamic acid by such a method. The heating time of each of the above treatments varies depending on the treatment amount of the polyamic acid solution for dehydration ring closure and the heating temperature, but is generally performed within a range of 1 minute to 5 hours after the treatment temperature reaches the maximum temperature. It is preferable. Further, in order to shorten the heating time and manifest the characteristics, an imidizing agent and / or a dehydration catalyst is added to the polyamic acid solution, and the polyamic acid solution to which the imidizing agent and / or the dehydration catalyst is added is treated by the above method. You may heat by and may be imidized.

  The imidizing agent is not particularly limited, but a tertiary amine can be used. As the tertiary amine, a heterocyclic tertiary amine is more preferable. Preferable specific examples of the heterocyclic tertiary amine include pyridine, picoline, quinoline, isoquinoline, 1,2-dimethylimidazole and the like. Specific preferred examples of the dehydration catalyst include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride and trifluoroacetic anhydride.

  The imidizing agent and the dehydration catalyst are added in an amount of 0.5 to 5.0 times molar equivalent, more preferably 0.7 to 2.5 times molar equivalent, and particularly, to the amide group of the polyamic acid. Is preferably 0.8 to 2.0 times the molar equivalent. Further, the dehydration catalyst is 0.5 to 10.0 times molar equivalent, further 0.7 to 5.0 times molar equivalent, and particularly 0.8 to 3.0 times molar equivalent with respect to the amide group of the polyamic acid. Is preferred. When the imidizing agent and / or the dehydration catalyst are added to the polyamic acid solution, the imidizing agent and / or the dehydration catalyst may be added directly without being dissolved in the organic solvent, or may be dissolved in the organic solvent. In the method of adding directly without being dissolved in an organic solvent, the reaction may rapidly proceed before the imidizing agent and / or the dehydration catalyst diffuse, and a gel may be formed. More preferably, the solution obtained by dissolving the imidizing agent and / or the dehydration catalyst in an organic solvent is mixed with the polyamic acid solution.

  The polyimide of the present invention can be produced by coating a support with a polyamic acid solution and drying or heating. In the present specification, the film-shaped polyimide obtained by the method described above may be referred to as a polyimide film. Here, the polyamic acid solution may be a partially imidized solution. Drying or heating may be carried out under air or under a nitrogen atmosphere. From the viewpoint of transparency, drying or heating under a nitrogen atmosphere is particularly preferable.

  As the support to which the polyamic acid solution is applied, a glass substrate; a metal substrate such as SUS or a metal belt; a plastic film such as polyethylene terephthalate, polycarbonate, polyacrylate, polyethylene naphthalate or triacetyl cellulose is used. It is not limited to. It is preferable to use a glass substrate in order to adapt to the current batch type device manufacturing process.

  Regarding the drying temperature or the heating temperature during the production of the polyimide film, it is possible to select the conditions according to the process, and it is not particularly limited as long as it does not affect the characteristics.

  The transparency of the polyimide is represented by, for example, the total light transmittance (TT) or haze according to JIS K7105-1981. When a polyimide film is used for the purpose of the present invention described below, the total light transmittance of the polyimide is preferably 80% or more, more preferably 85% or more. The haze is preferably 2.0% or less, more preferably 1.0% or less. In the use of the present invention, polyimide is required to have high transmittance in the entire wavelength region, but polyimide tends to absorb light on the short wavelength side, and the film itself is often colored yellow. For use in the application of the present invention, polyimide has a light transmittance at a wavelength of 400 nm of preferably 50% or more, more preferably 60% or more, when the film thickness is 10 to 15 μm. More preferably, it is greater than 70%.

  The light transmittance at a wavelength of 400 nm is measured by an ultraviolet-visible spectrophotometer. By imparting transparency in this way, the polyimide film can be used as a transparent substrate for glass substitute applications and the like.

  The polyimide of the present invention has low linear thermal expansion characteristics as film characteristics and dimensional stability before and after heating. For example, when these values are measured by thermomechanical analysis (TMA), TMA7100SS manufactured by Hitachi High-Tech Science Co., Ltd. is used (sample size width 3 mm, length 10 mm, film thickness is measured, and the cross-sectional area of the film is calculated. ), A load of 29.4 mN and a temperature of 10 ° C./min to 20 ° C. to 350 ° C. and then to −30 ° C., the strain of the sample per unit temperature at 100 to 300 ° C. during cooling. The coefficient of linear expansion was determined from the amount of change. It is possible to obtain a polyimide having a linear thermal expansion coefficient of 20 ppm / K or less, more preferably 15 ppm / K or less in the range of 100 ° C to 300 ° C.

  The glass transition temperature is TMA7100SS (manufactured by Hitachi High-Tech Science Co., Ltd.) (sample size width 3 mm, length 10 mm, film thickness is measured, film cross-sectional area is calculated), load is 29.4 mN and temperature is 10 ° C./min. The amount of change in strain of the film when the temperature was raised to 10 to 400 ° C. was measured, and the temperature at the inflection point of this change was taken as the glass transition temperature. From the viewpoint of heat resistance, the higher the glass transition temperature, the better. Specifically, the temperature is preferably 300 ° C. or higher, and more preferably 350 ° C. or higher in that it can handle high process temperatures.

  Further, in a batch type device manufacturing process in which a polyamic acid solution is applied on a support such as glass, heated and imidized to form an electronic element or the like to form a substrate, and then peeled off, the support and the polyimide are used. It is necessary that the adhesiveness between and is good. The term "adhesion" as used herein means the adhesion strength. After forming a substrate by forming an electronic element or the like on the polyimide film on the support, in the manufacturing process of peeling the polyimide substrate on which the electronic element or the like is formed from the support, it is said that the adhesiveness with the inorganic substrate is excellent. , An electronic element or the like can be formed or mounted more accurately. Adhesion was evaluated as the peel strength by averaging the peel strength when peeling 50 mm under the conditions of sample width 10 mm, 23 ° C. and 55% RH according to ASTM D-1867-01 standard by Toyo Seisakusho strobograph VESID. The higher the peel strength, the better from the viewpoint of the manufacturing process of stacking electronic elements and the like on the substrate. Specifically, it is preferably 0.03 N / cm or more, more preferably 0.1 N / cm or more. On the other hand, the peel strength is preferably not too high from the viewpoint of easy peeling of the substrate from the support. Specifically, it is preferably 0.25 N / cm or less. That is, the peel strength suitable for the batch type manufacturing process is preferably 0.10 to 0.25 N / cm.

  In the manufacturing process, the polyimide substrate on which electronic elements and the like are laminated is separated from the inorganic substrate by laser irradiation. When the polyimide film does not absorb the laser wavelength at all and transmits it, peeling by the laser becomes difficult, so the polyimide film needs to absorb the laser wavelength.

  Usually, the wavelength of the laser used for laser peeling is around 300 nm, and since it is necessary to absorb the wavelength, the Cut off wavelength is preferably 340 nm or more, more preferably 355 nm or more. Further, if the Cut Off wavelength exceeds 380 nm, it is difficult to maintain transparency, so the Cut Off wavelength is preferably 340 nm to 380 nm. However, the Cut off wavelength here means a wavelength at which the transmittance is 0.1% or less, which is measured by an ultraviolet-visible spectrophotometer.

  The polyamic acid and polyimide according to the present invention may be subjected to a coating or molding process for producing a product or a member as they are, but a laminate for further processing such as coating on a film-shaped molded product. It can also be used as In order to be subjected to a coating or molding process, the polyamic acid and the polyimide are dissolved or dispersed in an organic solvent as the case requires, and further, a photo- or thermosetting component, a non-polymerizable binder other than the polyamic acid and the polyimide according to the present invention. A resin and other components may be blended to prepare a polyamic acid and polyimide resin composition.

  In order to impart processing properties and various functionalities to the polyamic acid and polyimide according to the present invention, various other organic or inorganic low-molecular or high-molecular compounds may be added. For example, dyes, surfactants, leveling agents, plasticizers, fine particles, sensitizers and the like can be used. The fine particles include organic fine particles such as polystyrene and polytetrafluoroethylene, inorganic fine particles such as colloidal silica, carbon, and layered silicate, which may have a porous or hollow structure. The function or form thereof includes pigments, fillers, fibers and the like.

  The polyimide film according to the present invention may have various inorganic thin films such as metal oxides and transparent electrodes formed on the surface thereof. The method of forming these inorganic thin films is not particularly limited, and examples thereof include a CVD method, a sputtering method, a vacuum deposition method, a PVD method such as an ion plating method, and the like.

  The polyimide according to the present invention, in addition to heat resistance, low thermal expansion property, transparency, and good adhesion between the support and the polyimide, fields and products where these properties are effective, for example, printed matter. , Color filters, flexible displays, optical films, liquid crystal display devices, image display devices such as organic EL and electronic paper, 3-D displays, touch panels, transparent conductive film substrates or solar cells, and more preferably at present. It is more preferable to use a substitute material for the portion where glass is used.

  Further, the polyamic acid, the polyimide and the polyamic acid solution according to the present invention are a batch type in which a polyamic acid solution is applied on a support, heated to be imidized, and an electronic element or the like is formed to form a substrate, and then peeled off. Can be suitably used for the device manufacturing process. Therefore, in the present invention, a method for producing an electronic device including a substrate forming step of applying a polyamic acid solution on a support, heating it for imidization, and forming an electronic element or the like on the polyimide film formed on the support. Is also included. Further, such a method for manufacturing an electronic device may further include a step of peeling the polyimide substrate on which the electronic element and the like are formed from the support after the substrate forming step.

(Evaluation methods)
The material characteristic values and the like described in the present specification are obtained by the following evaluation methods.

(1) Transmittance of polyimide film Using a UV-Vis near-infrared spectrophotometer (V-650) manufactured by JASCO Corporation, the transmittance of the polyimide film at 200 to 800 nm was measured, and the transmittance of light at a wavelength of 400 nm was measured. Was used as an index. In addition, the wavelength at which the transmittance is 0.1% or less (Cut off wavelength) was also obtained. In addition, a yellow index (YI) was calculated as an index representing yellowness from the formula described in JIS K7373.

(2) Linear thermal expansion coefficient (CTE) of film
The linear thermal expansion coefficient was measured using TMA7100SS manufactured by Hitachi High-Tech Science Co., Ltd. (sample size width 3 mm, length 10 mm, film thickness was measured to calculate the cross-sectional area of the film), and the load was 29.4 mN and 10 The linear expansion coefficient was obtained from the amount of change in strain of the sample per unit temperature at 100 to 300 ° C during cooling when the temperature was once raised from 20 ° C to 350 ° C at ℃ / min and then cooled to -30 ° C. It was

(3) Glass transition temperature (Tg) of polyimide film
Using Hitachi High-Tech Science Co., Ltd. TMA7100SS (sample size width 3 mm, length 10 mm, film thickness is measured and cross-sectional area of the film is calculated), load is 29.4 mN, and temperature is 10 to 400C at 10C / min. The amount of change in strain of the film when the temperature was raised to was measured, and the temperature at the inflection point of this amount of change was taken as the glass transition temperature.

(4) Total light transmittance (TT) of polyimide film
It was measured by a method described in JIS K7105-1981 using an integrating sphere type haze meter 300A manufactured by Nippon Denshoku Industries.

(5) Haze of polyimide film It was measured by a method described in JIS K7105-1981 using an integrating sphere type haze meter 300A manufactured by Nippon Denshoku Industries Co., Ltd.

(6) Glass adhesion test According to ASTM D-1867-01 standard by Toyo Seisakusho strobograph VESID, sample width 10 mm, 23 ° C., peeling 50 mm under 55% RH conditions, peeling the average value of 90 ° peel strength. It was evaluated as strength.

(Example 1)
<Polymerization of polyamic acid>
A 500 mL glass separable flask equipped with a stirrer equipped with a stainless steel stir bar and a nitrogen inlet tube was charged with 113.3 g of NMP as an organic solvent for polymerization, and 5.6 g of CHDA was added and stirred. To this solution, 13.8 g of BPDA and 0.7 g of TMHQ were added simultaneously, heated at 80 ° C. for 60 minutes, then cooled, and stirred at room temperature (23 ° C.) for 5 hours to obtain a polyamic acid solution. The charging ratio of each monomer was BPDA: 97 mol% and TMHQ: 3 mol% when CHDA was 100 mol%. The charging concentration of the diamine compound and the tetracarboxylic dianhydride in this reaction solution was 15% by weight based on the total reaction solution.

<Preparation of polyimide film>
The polymerized polyamic acid solution was applied on a glass plate with a bar coater and dried in air at 80 ° C. for 30 minutes and under nitrogen atmosphere at 350 ° C. for 1 hour to obtain a polyimide film having a thickness of 10 to 15 μm. The properties of the obtained polyimide film are shown in Table 1.

(Examples 2 to 5, 9 and Reference Examples 6 to 8 )
A polyamic acid solution and a polyimide film were obtained in the same manner as in Example 1 except that the diamine component, the tetracarboxylic acid component and the organic solvent described in Table 1 were used.

(Example 10)
To 67 g of the polyamic acid solution synthesized in Example 5, 0.1 g of DMI was added and stirred to obtain a uniform solution.

<Preparation of polyimide film>
The obtained solution was applied on a glass plate with a bar coater and dried in air at 80 ° C. for 30 minutes and under nitrogen atmosphere at 350 ° C. for 1 hour to obtain a polyimide film having a thickness of 10 to 15 μm. The properties of the obtained polyimide film are shown in Table 1.

(Example 11)
0.01 g of APS was added to 67 g of the polyamic acid solution synthesized in Example 2, and the mixture was stirred and left for 12 hours to obtain a uniform solution.

<Preparation of polyimide film>
The obtained solution was applied on a glass plate with a bar coater and dried in air at 80 ° C. for 30 minutes and under nitrogen atmosphere at 350 ° C. for 1 hour to obtain a polyimide film having a thickness of 10 to 15 μm. The properties of the obtained polyimide film are shown in Table 1.

(Comparative Example 1)
A 500 mL glass separable flask equipped with a stirrer equipped with a stainless steel stir bar and a nitrogen inlet tube was charged with 113.3 g of NMP as an organic solvent for polymerization, and 5.6 g of CHDA was added and stirred. To this solution, 13.8 g of BPDA was added, heated at 80 ° C. for 60 minutes, then cooled, and stirred at room temperature (23 ° C.) for 5 hours to obtain a polyamic acid solution. The charging ratio of the monomers was BPDA: 100 mol% when CHDA was 100 mol%. The charging concentration of the diamine compound and the tetracarboxylic dianhydride in this reaction solution was 15% by weight based on the total reaction solution.

<Preparation of polyimide film>
The polymerized polyamic acid solution was applied on a glass plate with a bar coater and dried in air at 80 ° C. for 30 minutes and under nitrogen atmosphere at 350 ° C. for 1 hour to obtain a polyimide film having a thickness of 10 to 15 μm. The properties of the obtained polyimide film are shown in Table 1.

(Comparative Examples 2-5)
A polyamic acid solution and a polyimide film were obtained in the same manner as in Example 1 except that the diamine component, the tetracarboxylic acid component and the organic solvent described in Table 1 were used.

The abbreviations are shown below.
NMP: 1-methyl-2-pyrrolidone BPDA: 3,3'-4,4'-biphenyltetracarboxylic dianhydride a-BPDA: 2,3-3 ', 4-biphenyltetracarboxylic dianhydride TMHQ: 1,4-phenylene bis (trimellitate dianhydride)
ODPA: 4,4 ″ -oxydiphthalic acid dianhydride CHDA: trans-1,4-cyclohexanediamine APS: γ-aminopropyltriethoxysilane DMI: 1,2-dimethylimidazole

Claims (13)

A polyamic acid represented by the repeating unit of the general formula (1),
Among the constituent units, it includes the general formula in which A (2) and (3), viewed contains at least 50 mol% or more (4) in B,
At least 80 mol% or more of the structural unit A represented by (1) is occupied by (2) and (3), and the molar ratio represented by (2) / (3) is 97/3. A polyamic acid characterized by being in the range of 80/20 .

A polyamic acid solution containing the polyamic acid according to claim 1 and an organic solvent. A method for producing a polyimide, which is obtained by coating the support with the polyamic acid solution according to claim 2 . A polyimide represented by the general formula (5) ,

Among the constituent units, it includes the general formula in which A (2) and (3), viewed contains at least 50 mol% or more (4) in B,
At least 80 mol% or more of the structural unit A represented by (5) is occupied by (2) and (3), and the molar ratio represented by (2) / (3) is 97/3. A polyimide having a range of up to 80/20. The polyimide according to claim 4 , which has a light transmittance of 50% or more at a wavelength of 400 nm when the film thickness is 10 to 15 μm. The coefficient of thermal expansion at 100 to 300 ° C. when the film thickness is 10 to 15 μm is 20 ppm / K or less, and the polyimide according to claim 4 or 5 . Polyimide according to any one of claims 4-6, wherein the glass transition temperature of 300 ° C. or higher. Polyimide according to any one of claims 4 to 7, 90 degree peel strength between the inorganic layer and wherein the at 0.03 N / cm or more. The Cutoff wavelength when the film thickness is 10 to 15 μm is 340 nm or more, and the polyimide according to any one of claims 4 to 8 . A substrate containing the polyimide according to any one of claims 4 to 10 . Optical material containing a polyimide according to any one of claims 4-9. The image display device containing polyimide according to any one of claims 4-9. Electronic devices containing polyimide according to any one of claims 4-9.