JP2009142999A - Apparatus and method for manufacturing polyimide film, and polyimide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for manufacturing a polyimide film having a thickness of 10 μm or less, by which the film can be continuously and stably manufactured without causing fracture of film so as to have a uniform thickness, without using expensive die and coating liquid supporter, and without depending on complicated manufacturing equipment, and to provide the polyimide film obtained by the apparatus and method. <P>SOLUTION: The manufacturing apparatus of polyimide film comprises a slit die, a coating liquid supporter of a polyimide precursor solution, and a heating imide conversion device, wherein the slit die is provided with an interval adjusting mechanism for retaining an interval between the tip part of the slit die and the surface of the coating liquid supporter constant, and the heating imide conversion device is provided with at least one heating roller for causing a polyimide precursor gel film to contact with the surface of the roller to complete imide conversion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyimide film manufacturing apparatus and a manufacturing method thereof, and a polyimide film obtained therefrom.

  Polyimide film has been highly evaluated as the most excellent heat-resistant film, and is used for applications such as flexible printed circuit boards, TAB tape, mobile phone vibration membranes, speaker vibration membranes, and other electronic devices and parts. Has been.

  In recent years, as these electronic devices / parts are required to be reduced in size and weight, the polyimide film used is required to be further thinned. Specifically, it is a polyimide film having a thickness of 10 μm or less, and further an ultra-thin polyimide film having a thickness of 5 μm or less.

  Conventionally, as a method for obtaining a polyimide film, a polyimide solution or a polyimide precursor solution is cast on a coating solution support such as an endless steel belt or a heating roll, and the solution is dried to obtain a self-supporting polyimide precursor. A method is used in which a gel film is formed, peeled off from the coating liquid support, and then heat treated while gripping and transporting both ends (ears) of the film with a tenter.

  However, in a thin film polyimide film having a film thickness of less than 10 μm, the thickness of the film is required to be uniform as well as the film thickness is thin. ) Or in the width direction (TD), there is a problem that thickness variation is likely to occur.

  These thin film polyimide films are usually polyimides having self-supporting properties from the support after extruding the polyimide precursor solution onto the coating solution support, adhering it to a uniform thickness and drying it on the support. After peeling off the precursor gel film, the polyimide precursor gel film can be obtained by stepwise baking to a temperature at which imidization is completed. When extruding the polyimide precursor solution to the coating solution support, if the coating film is not uniform, the film thickness of the obtained thin film polyimide film varies, so the uniformity of the coating film becomes important. In the case of a thermoplastic polyimide film, it is possible to improve the thickness variation by, for example, performing a stretching process at a temperature at which the film acquires plasticity, but in a non-thermoplastic polyimide film, the plasticity is expressed. Therefore, it is difficult to perform the stretching treatment to such an extent that the thickness fluctuation can be improved, and therefore, the uniformity of the coating film when the polyimide precursor solution is extruded onto the coating solution support becomes more important.

  In the conventional manufacturing method, the processing accuracy of the die and the coating liquid support is improved, and the positions of the die and the coating liquid support are mechanically adjusted. However, these methods not only increase the processing cost of the die and the coating liquid support, but also require a very complicated structure in the manufacturing equipment, which makes the manufacturing equipment expensive. However, there was a problem that the thickness uniformity was not sufficient.

  Furthermore, in a thin film polyimide film having a film thickness of less than 10 μm, if the heat treatment is carried out while gripping and transporting both ends of the polyimide precursor gel film with a tenter, the film strength is reduced due to the shrinkage due to the thinness. There is a problem that it cannot endure and breaks from the edge.

  Several methods for producing thin film polyimide films have been disclosed. For example, according to Patent Document 1, an ultra-thin polyimide film having a thickness of 10 μm or less can be produced by a method in which a raw material monomer is deposited on a substrate to form a film. Further, according to Patent Documents 2 and 3, a method is shown in which a polyimide monomolecular film is obtained by the Langmuir-Blodget method and then laminated to form a predetermined film thickness.

However, these are not suitable for continuous production and have a problem that stable production is difficult. That is, at present, there is no inexpensive and stable method for producing a thin film polyimide film.
JP 04-080235 A JP-A-3-139522 JP 63-019212

  The present invention relates to a method for producing a thin film polyimide film having a film thickness of 10 μm or less, and does not use an expensive die and coating solution support, and has a uniform thickness regardless of complicated production equipment. An object of the present invention is to provide a thin-film polyimide film production apparatus and method, and a thin-film polyimide film obtained from the production apparatus, which can be continuously produced and can be stably produced without causing breakage of the film.

  As a result of intensive studies, the present inventors have found that a thin-film polyimide film having a uniform thickness can be produced without using an expensive die and coating solution support and without using complicated production equipment.

  That is, the present invention has the following configuration.

  An apparatus for producing a polyimide film by continuously applying a polyimide precursor solution from a slit die onto a support, followed by heating imide conversion, wherein the apparatus is a slit die, a coating liquid support for a polyimide precursor solution. And a heating imide conversion device, and a polyimide film manufacturing device comprising a gap adjusting mechanism for maintaining a constant gap between the tip end of the slit die and the surface of the coating liquid support. .

  The said space | interval adjustment mechanism is a polyimide film manufacturing apparatus provided with the contact guide or distance sensor for detecting the space | interval of the front-end | tip part of this slit die, and the said coating liquid support body surface.

  The said coating liquid support body is a polyimide film manufacturing apparatus which is a rotating drum.

  The heated imide conversion apparatus is a polyimide film manufacturing apparatus including at least one heating roll for bringing the polyimide precursor gel film into contact with the roll surface to complete the imide conversion.

  It is a polyimide film manufacturing apparatus provided with the nip roller for pressing the said polyimide precursor gel film on the surface of a heating roll.

  A polyimide manufacturing apparatus that applies a polyimide precursor solution from the slit die to the coating liquid support surface while detecting the distance between the slit die tip and the coating liquid support surface with the contact guide or the distance sensor was used. It is a manufacturing method of a polyimide film.

  It is a manufacturing method of the polyimide film whose temperature of the said slit-die front-end | tip part is 0 degreeC or more and 40 degrees C or less.

  It is a manufacturing method of the polyimide film whose 23 degree C viscosity of the said polyimide precursor solution is 50 Ps to 5000 Ps.

  It is a manufacturing method of the polyimide film whose temperature of the said coating liquid support body surface is 40 degreeC or more and 200 degreeC or less.

  It is a manufacturing method of the polyimide film whose application | coating speed | rate which apply | coats a polyimide precursor solution to the said coating liquid support surface from the said slit die is 50 mm / min or more.

  The polyimide precursor gel film having a self-supporting property dried on the coating solution support is peeled off from the coating solution support and led to the heating imide conversion device, and at least one having a surface temperature of 150 ° C. or more. It is the manufacturing method of the polyimide film which makes the said polyimide precursor gel film contact the surface of a heating roll, and is imide-converted in steps.

  The stepwise means that the temperature of the heating roll is gradually increased, heat applied to the polyimide precursor gel film is gradually applied, and baking is performed. As a stepwise baking method, specifically, there is a method of bringing a film into contact with a heating roll set at a predetermined temperature. When there are a plurality of heating rolls, it is advisable to set the temperature appropriately so that the temperature increases stepwise. In stepwise firing, the firing start temperature is specifically 150 ° C. or higher. The temperature gradient when raising the temperature stepwise is not particularly limited, and heat may be gradually added at a constant rate of temperature increase, or heat may be added in several temperature steps. . As another stepwise firing method, a method using a metal endless belt or the like can also be employed. In this case, the temperature may be increased stepwise in the direction of travel of the metal endless belt. When heat is gradually applied at a constant temperature increase rate, heat should be gradually applied at a temperature increase rate of 1 ° C / min to 200 ° C / min, preferably 10 ° C / min to 100 ° C. / Min heating rate. If the rate of temperature rise is 1 degree C / min or more, a film can be manufactured without impairing productivity, and if the rate of temperature rise is 200 degrees C / min or less, the appearance such as wrinkles and blisters accompanying solvent volatilization will occur. A film can be produced without causing defects.

It is the manufacturing method of the polyimide film whose tension concerning the said polyimide precursor gel film is 1.1 kgf / mm < ² > or less.

  It is a polyimide film having a thickness of 1 μm or more and 10 μm or less.

  The thin film polyimide film manufacturing apparatus and method for manufacturing the thin film polyimide film having a thickness of 10 μm or less according to the present invention, and the thin film polyimide film obtained therefrom, as described above, the slit die and the coating liquid for applying the polyimide precursor solution A distance adjustment mechanism that keeps the distance to the support constant is installed, and the polyimide precursor solution is extruded onto the coating liquid support surface from a slit die that moves freely in the width direction (TD) of the polyimide film. And the step of drying on the coating solution support and the self-supporting polyimide precursor gel film dried on the coating solution support are peeled off and heated to one or more 150 ° C. or more Characterized by having a step of firing stepwise in a state where the polyimide precursor gel film is in contact with the surface of the heated roll That. By this, there is an effect that a thin film polyimide film having a uniform film thickness, which is not broken by gripping a tenter, can be stably and continuously manufactured, and a manufacturing method and a manufacturing apparatus for a high quality thin film polyimide film, and those The thin film polyimide film obtained from is extremely effective industrially.

  An embodiment of the present invention will be described as follows, but the present invention is not limited to this.

  In the present invention, the slit die for applying the polyimide precursor solution is provided with an interval adjusting mechanism for keeping the distance between the coating solution support and the slit die constant, and the polyimide precursor solution is applied from the slit die to the surface of the coating solution support. The polyimide precursor gel film having a uniform thickness, dried on the support and dried and self-supporting is peeled off from the support, and the polyimide precursor gel film is continuously at 150 ° C. or higher. To be transported and fired.

<Polyimide precursor solution adjustment>
An aromatic diamine component and an aromatic tetracarboxylic acid component are reacted in an organic polar solvent to prepare a polyimide precursor solution.

  Examples of the aromatic diamine component of the present invention include 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenyl ether, 1,4-diaminobenzene, 1,3-diaminobenzene, 2 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,4-diaminotoluene, 3,4'-biphenyldiamine, 3,4'-diaminodiphenyl sulfoxide, 2,2-bis (3-aminophenyl) propane 4,4′-diaminobenzophenone, 3,3′-biphenyldiamine, 3,4′-diaminodiphenyl ether, 2,6-diaminotoluene, 4,4′-biphenyldiamine, 3,3′-diaminodiphenyl sulfone, 3, , 4'-diaminodiphenylmethane, 3,3'-diaminodiphenyl ether, 4 4′-bis (4-aminophenyl) sulfide, 3,3′-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) propane, 2,2- (3-aminophenyl) (4-aminophenyl) propane 3,3′-diaminobenzophenone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-bis (4-aminophenyl) sulfide, 4,4′-diaminodiphenyl sulfoxide, 3,4 '-Diaminobenzophenone, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfone, 2,5-diaminotoluene, 3,3'-diaminodiphenyl ether, 4,4'-bis (4-aminophenyl) Sulfide, 3,3′-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) propane, 2,2- (3-aminophenyl) (4-aminophenyl) propane, 3,3′-diaminobenzophenone, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,2′-dimethyl-4, 4'-diaminobiphenyl, 3,4'-bis (4-aminophenyl) sulfide, 3,3'-bis (4-aminophenyl) sulfide, 4,4'-diaminodiphenyl sulfoxide, 3,4'-diaminobenzophenone 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfone, 2,5-diaminotoluene, 3,3′-hydroxy-4,4′-diaminobiphenyl, 1,3-bis- (3- Aminophenoxy) benzene, 1,3-bis- (4-aminophenoxy) benzene, diaminobenzoanilide, methylenedianiline Gerare These may be used singly or in combination.

  The aromatic tetracarboxylic dianhydride of the present invention includes 3,4,3 ′, 4′-benzophenonetetracarboxylic dianhydride, pyromellitic anhydride, 3,4,3 ′, 4′-biphenyltetra Carboxylic dianhydride, 3,4,3 ′, 4′-diphenyl sulfoxide tetracarboxylic dianhydride, 2,3,3 ′, 4′-diphenyl ether tetracarboxylic dianhydride, 3,4,3 ′, 4′-diphenyl sulfide tetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-diphenylmethane tetracarboxylic dianhydride, 3, 4,3 ′, 4′-diphenyl (2,2-isopropylidene) tetracarboxylic dianhydride, 2,3,3 ′, 4′-diphenylsulfoxide tetracarboxylic dianhydride, 3,4,3 ′ , 4′-diphenyl ether tetracarboxylic dianhydride, 3,4,3 ′, 4′-diphenylsulfone tetracarboxylic dianhydride, 2,3,3 ′, 4′-diphenylsulfonetracarboxylic dianhydride, 2,3,3 ′, 4′-diphenylsulfide tetracarboxylic dianhydride, 3,4,3 ′, 4′-diphenylsulfanetetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone Tetracarboxylic dianhydride, 2,3,3 ′, 4′-diphenyl (2,2-isopropylidene) tetracarboxylic dianhydride, 4,4 ′-(hexafluoroisopropyl) phthalic dianhydride, bisphenol An acid dianhydride etc. are mentioned, These can be used individually or in mixture.

  Polar organic solvents useful in the present invention include, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazo Lidinone, N-methylcaprolactam, hexamethylphosphoric triamide, 1,2-dimethoxyethane, diglyme, triglyme, tetrahydrofuran, 1,4-dioxane, γ-butyrolactone, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, Examples include diethoxyethane, dimethyl sulfoxide, and sulfolane. A preferred solvent is N, N-dimethylacetamide. These solvents can be used alone or as a mixture, or mixed with other solvents such as toluene, xylene, ie, aromatic hydrocarbons, methanol, ethanol, ie, alcohol.

  The viscosity at 23 degrees C of the polyimide precursor solution of the present invention is preferably 50 Ps or more and 5000 Ps or less. In the production process of the polyimide film in the present invention, if the viscosity is less than 50 Ps, the coating film repels and a uniform coating film cannot be obtained. If the viscosity exceeds 5000 Ps, bubbles tend to bite and uniform coating is performed. A film cannot be obtained.

  As for the molecular weight of the polyimide precursor, a polyimide precursor having a desired molecular weight can be obtained by changing the mixing ratio of the aromatic tetracarboxylic dianhydride and the aromatic diamine. In the present invention, the mixing ratio for obtaining a preferable molecular weight is 80: 100 to 99: 100. The mixing ratio may be greater or less than tetracarboxylic dianhydride or aromatic diamine.

  In addition, in manufacturing a polyimide film, additives, such as a lubricant, a leveling agent, an antifoamer, and an imidizing agent, can also be added as needed.

  Moreover, when manufacturing a polyimide film, functional fillers and fillers, such as a metal and ceramics, can also be added as needed.

<Polyimide precursor gel film formation>
In the polyimide precursor gel film formation in the present invention, an interval adjusting mechanism for maintaining a constant distance between the slit die for applying the polyimide precursor solution and the coating liquid support is installed, and the width direction of the coating liquid support ( The polyimide precursor solution is extruded from the slit die freely moving to TD) onto the surface of the coating solution support, adhered to a uniform thickness, and dried on the coating solution support, thereby providing an organic solvent for the polyimide precursor solution. Can be performed by volatilizing a part of the polyimide precursor, imidizing a part of the polyimide precursor, and forming a self-supporting polyimide precursor gel film, and then peeling the polyimide precursor gel film from the support Good. The slit die that freely moves in the width direction of the coating liquid support is a structure for keeping the distance between the coating liquid support and the slit die constant. According to normal machining, even a coating liquid support machined with high precision has run out of cores of several microns to several tens of microns, resulting in a change in the distance between the coating liquid support and the slit die. Although it always occurs, the influence of the runout of the coating liquid support can be substantially eliminated by having a mechanism for rotating the slit die.

  The distance adjusting mechanism is a mechanism for maintaining a constant distance between the coating liquid support and the slit die, and a contact guide for detecting a distance between the tip of the slit die and the surface of the coating liquid support or It has a distance sensor. The contact guide and the distance sensor have an adjustment function for increasing or decreasing the clearance between the coating liquid support and the slit die. The mechanism using the contact guide is a mechanism for applying the polyimide precursor solution in a state where at least two contact guides set at a predetermined interval are always in contact with at least two places on the surface of the coating liquid support. The mechanism using the distance sensor is a mechanism for applying the polyimide precursor solution while detecting the distance between the slit die and the surface of the coating liquid support so that the distance between the slit die and the coating liquid support is always constant.

  The contact guide that keeps the distance between the coating solution support and the slit die constant can first adjust the clearance between the coating solution support and the slit die between 10 μm and 1000 μm. A slit die with a contact guide that maintains a constant distance between the coating solution support and the slit die is placed so that the contact guide contacts the coating solution support, and the slit die is directed toward the center of the coating solution support. Press. The entire slit die is attached with a cylinder or the like at the rear, and is pressed with a pressing pressure that does not leave the contact guide away from the coating liquid support. Thereby, even if the coating liquid support surface to which the polyimide precursor solution is applied is slightly displaced, the contact guide follows the displacement, and the slit die moves freely in the width direction (TD). The distance between the slit die and the coating liquid support can always be kept constant.

  After applying the polyimide precursor solution, by drying on the coating solution support, a part of the organic solvent of the polyimide precursor solution is volatilized, and a part of the polyimide precursor is imidized, self-supporting property The polyimide precursor gel film can be formed by forming a polyimide precursor gel film from the coating solution support. The temperature of the slit die is preferably 0 ° C. or higher and 40 ° C. or lower, and more preferably 5 ° C. or higher and 30 ° C. or lower. By setting the temperature to 0 ° C. or higher, the polyimide precursor solution can be extruded from the slit die onto the coating solution support without being affected by moisture condensation in the air. Further, by setting the temperature of the slit die to 40 ° C. or less, it is possible to suppress volatilization of the organic solvent from the polyimide precursor solution inside the slit die, and stable extrusion can be performed.

  The coating speed when the polyimide precursor solution is applied to the coating liquid support surface from the slit die to a predetermined thickness is preferably 50 mm / min or more. If it is slower than 50 mm / min, the productivity is too bad, which is not practical when considering commercialization.

  The drying temperature on the coating solution support is preferably 40 ° C. or higher and 200 ° C. or lower, and more preferably 80 ° C. or higher and 150 ° C. or lower. If the drying temperature is set to 40 ° C. or higher, a film can be produced with good productivity when the volatilization rate of the organic solvent is taken into consideration. Further, by setting the drying temperature to 200 ° C. or less, rapid solvent volatilization can be avoided, and appearance defects such as wrinkles and blisters resulting therefrom can be eliminated. The drying time is several seconds to several tens of minutes, preferably 1 minute to 30 minutes, and is appropriately set in relation to the heat treatment temperature.

  The solvent remains in the dried polyimide precursor gel film obtained as described above. In the present invention, this is defined as the solvent remaining rate. The amount of solvent present in the polyimide precursor solution at the time of application was set to 100% by weight, and the solvent residual rate was calculated from the weight loss when the polyimide precursor gel film was measured for thermal weight loss. The polyimide precursor gel film after drying is subsequently heat-treated at a high temperature for completion of imidization and volatilization of the residual solvent. The residual solvent ratio of the polyimide precursor gel film at this time is 5 wt% to It is preferably 50% by weight. Furthermore, it is more preferable that it is 10 to 30 weight%. If the residual solvent ratio is 5% by weight or more, the film loses toughness and can be fired without breaking, and if the residual solvent ratio is 50% by weight or less, the polyimide precursor gel film can have self-supporting properties. .

  The coating liquid support may be a drum shape or an endless steel belt.

  The contact guide for keeping the distance between the coating liquid support and the slit die constant is not particularly limited, but a heat-resistant and slippery part is preferable, and a rotatable cylindrical part such as a bearing is more preferable. The material of the contact guide that keeps the distance between the coating solution support and the slit die constant may be either metal or resin, or a composite of metal and resin.

<Baking of polyimide precursor gel film>
In the present invention, the polyimide precursor gel film is baked in a state where the polyimide precursor gel film is brought into contact with the heated roll surface heated to 150 ° C. or higher.

  By baking in a state where the polyimide precursor gel film is in contact with the surface of the heating roll, the polyimide precursor gel film or the thin film polyimide film does not break, and continuous production is possible and stable production is possible.

  When the polyimide precursor gel film is imidized by heat, the first stage temperature in the firing step is preferably 150 ° C. or higher and 250 ° C. or lower. Further, it is more preferable to apply heat stepwise at a temperature of 150 ° C. or higher and 400 ° C. or lower. As a method of applying heat stepwise, the temperature is increased from 50 ° C. to 150 ° C. with respect to the temperature of the previous step. preferable. Thus, in this firing step, removal of the residual solvent and imidization proceed at an appropriate rate, and a thin film polyimide film free from defects in appearance such as blisters and wrinkles can be obtained.

  When the polyimide precursor gel film is imidized by heat, it is preferable that the solvent remaining rate of the film after the first stage baking in the baking process is 0.5 wt% to 20 wt%. Furthermore, it is more preferable that it is 1 to 10 weight%. If the residual solvent ratio is 0.5% by weight or more by the first stage baking, there will be no appearance change such as wrinkles or blisters due to the volatilization of the solvent, and the residual solvent will remain by the first stage baking. If the rate is 20% by weight or less, there will be no appearance deformation such as wrinkles and blisters due to solvent volatilization during the subsequent second stage baking.

  It is preferable that a nip roller that rotates and follows the heating roll heated to 150 ° C. or more is placed in contact with the heating roll, and the polyimide precursor gel film is brought into contact with the heating roll via the nip roller. The nip roller in the present invention is in contact with the heating roll and rotates in accordance with the rotation of the heating roll. The nip roller is preferably provided with a fulcrum having a different axis from that of the nip roller so that the position of the nip roller varies. By having the above structure, an increase in nip pressure due to thermal expansion of the heating roll and nip roller can be prevented, and the nip pressure can always be kept constant. The film will pass between the heating roll and the nip roller, and it can be brought into contact with the heating roll sequentially while stretching the wrinkles etc. of the polyimide precursor gel film generated during transportation, and there is no appearance defect, thickness A uniform thin film polyimide film can be obtained.

In the firing step, the tension applied to the polyimide precursor gel film is preferably 1.1 kgf / mm ² or less. If the tension applied to the polyimide precursor gel film is 1.1 Kgf / mm ² or less, unnecessary deformation of the film and further destruction of the film can be prevented.

  As the heating roll, a drum shape or an endless steel belt is appropriately used. What is necessary is just a structure which can apply temperature with respect to a polyimide precursor gel film in steps. For example, a plurality of heating rolls may be connected to stretch the film. Further, a heat source may be provided partially on one drum or the endless steel belt so that the temperature can be applied stepwise. If heating is performed step by step, imidization suddenly occurs when the polyimide precursor gel film is exposed to a high temperature, and the organic solvent contained in the polyimide precursor gel film is foamed and uniform film formation cannot be achieved. It is possible to avoid and obtain a good polyimide film.

  The heating method in the firing step may be any method as long as the polyimide precursor gel film on the heating roll can be heated stepwise. For example, a heat source such as a far-infrared heater, a sheathed heater, or a nichrome wire heater may be installed outside the heating roll. A heat source such as a hot air circulating furnace or a hot air generator may be used. Further, a heat source such as a heater or a heating medium may be embedded in the heating roll.

  The polyimide film obtained by the production method according to the present invention means a film having a thickness of 5 μm to several tens of μm, and of course, the thickness can be selected according to the use, but particularly by a tenter baking apparatus or the like. A thin film polyimide film that is difficult to manufacture by the manufacturing method can be obtained.

  Moreover, the polyimide film obtained by the manufacturing method according to the present invention has a very small film thickness variation, and the film thickness variation coefficient can be suppressed to 20% or less.

  An example of the manufacturing apparatus of the polyimide film concerning this invention is shown in FIG.

  First, in the drying step 10, a step of extruding the polyimide precursor solution mixed by the mixer into a film shape by the slit die 11 is performed, and in the reaction curing chamber, the film-like polyimide precursor solution extruded from the slit die is applied as a coating solution. A film is formed on the body 12. The precursor formed in the form of a film is imidized by being heated by a heating means while being moved by the rotation of the coating liquid support. In the drying step 10, combustible volatile components such as products generated with the reaction, mainly organic solvents, are evaporated.

  Since the polyimide film according to the present invention has a thickness of 10 μm or less and is extremely thin, when the polyimide precursor solution is formed into a film on the coating solution support, the distance between the slit die 11 and the coating solution support 12 is a little. If there is a slight change, the film thickness will vary greatly, and the value of the product will be greatly impaired.

  The slit die 11 for extruding the polyimide precursor solution is provided with a contact guide that keeps the distance from the casting drum and the endless belt constant. As a result, even if there is a slight shift in the roundness of the coating liquid support, the slit die 11 follows the shift, so that the polyimide precursor solution is always applied at a constant distance. .

  In addition, the slit die 11 is provided with a rotation shaft so as to move freely in the width direction, so that even if the runout of the coating liquid support occurs, the slit die 11 follows the runout. Thus, the position in the width direction can be changed. By providing these mechanisms, a polyimide film having no variation in film thickness can be obtained.

  The heating means in the drying step 10 includes the ambient temperature and the rotation speed of the belt or drum in order to prevent the danger of flammable combustible volatile components evaporated from the resin or to prevent the resin itself from igniting. For example, warm air, hot air, radiant heat, or belt heating is used. The temperature condition in the drying step 10 is such that, for example, the cast film is given self-supporting property under conditions such as 100 ° C.

Through these steps, the polyimide precursor gel film 13 is obtained by heating and drying the polyimide precursor gel film to the extent that the film has self-supporting properties, and then peeling off from the coating solution support.

  The polyimide precursor gel film 13 is transported and introduced into the baking step 15 via the transport roller 14 so as not to cause wrinkles or deflection, and is heat-treated. For example, the baking process 15 is comprised by the 1st heating roll 16 and the 2nd heating roll 17, and a film moves the inside of a baking process by operating these heating rolls by rotational drive in FIG. The polyimide precursor gel film is further imidized by gradually heating in the baking step 15 where heat curing is performed.

  The polyimide precursor gel film is placed on the first heating roll 16 via the first nip roller 18 that comes into contact with the first heating roll 16 when conveyed into the baking step 15. By installing the first nip roller 18, it can be fired without causing a deformation of an unfavorable appearance as a product such as wrinkles or sagging.

  The first nip roller 18 is in contact with the first heating roll 16 and is preferably a heat-resistant elastic roller such as silicone rubber so as not to cause scratches or wear.

  Similar to the first heating roll 16, a second nip roller 19 is also provided for the second heating roll, and since this has the same performance as the first nip roller 18, the film can be baked without causing deformation of the appearance. .

  The heating method of the baking process 15 uses the far-infrared heater on the outer side of a heating roll.

  In the baking step 15, the temperature is gradually raised to completely volatilize the organic solvent remaining in the film, and at the same time, imidation to polyimide is completed.

  The heat treatment temperature in the firing step 15 varies depending on the film thickness and the relationship with the type of organic solvent used for the reaction of the polyimide precursor. Specifically, the initial set temperature is preferably 150 ° C. to 250 ° C. for a film having a final film thickness of 5 μm, for example. At this stage, the polyimide precursor gel film is effectively dried and simultaneously the imidization reaction proceeds.

  Then, it is preferable to heat gradually and to make it into the temperature range whose maximum temperature is 300 degreeC or more and 500 degrees C or less. More preferably, it becomes the range of 350 degreeC or more and 400 degrees C or less. The temperature gradient reaching the maximum temperature is not particularly limited as long as the heat treatment is performed in the above temperature range. The heat treatment time is several seconds to several tens of minutes, preferably 1 minute to 20 minutes, and is appropriately set in relation to the heat treatment temperature.

  The temperature gradient is set according to the state of the film such as the film thickness and the degree of drying, and is not particularly limited. Specifically, for a film having a film thickness of 5 μm, it takes 10 minutes in a temperature range of 150 ° C. or more and 250 ° C. or less, and further 10 minutes in a temperature range of 300 ° C. or more and 400 ° C. or less.

  In the firing step 15, the completely imidized polyimide film is cooled in the cooling step 20. In the cooling step 20, the temperature may be lowered stepwise from the final firing temperature, or the film temperature may be lowered by exposure to room temperature.

  A cooling roller 21 is installed in the cooling step 20 as necessary.

  An example showing the application mechanism of the polyimide precursor solution in the present invention is shown in FIGS.

  Here, FIG. 2 is a diagram in which the portion is viewed from the top surface, and FIG. 3 is a diagram in which the portion is captured from the side surface. In FIG. 3, the contact guides 33 and 34 are omitted, but this is for facilitating the explanation of the side view, and the contact guides 33 and 34 are actually installed. The slit die 31 is provided with contact guides 33 and 34 for keeping the distance constant, whereby the distance between the slit die 31 and the coating liquid support 32 is kept constant. Further, the slit die 31 is provided with a rotating shaft 35, thereby having a mechanism that freely moves in the width direction of the coating liquid support 32. The rotating shaft 35 is installed on the fixed plate 36, and the slit die 31 and the coating liquid support 32 come into contact with each other through the contact guides 33 and 34 as the air cylinder 37 advances. Here, according to normal machining, the coating liquid support 32 has run out of core of several microns to several tens of microns, and a change in the distance between the coating liquid support 32 and the slit die 31 has occurred. In this case, the position of the slit die 31 changes as the air cylinder 37 moves back and forth, and the slit die 31 swings left and right around the rotation shaft 35 with respect to the swing in the width direction. A change in the distance of the liquid support 32 can be substantially eliminated.

  The portion 34 for fixing the slit die is extruded and formed into a film on the coating liquid support 32. The slit die 31 is a contact that keeps the distance from the coating liquid support 32 to be applied constant. By providing the guide 33 and the rotation shaft 34, the polyimide precursor solution is extruded onto the surface of the coating liquid support 32 from the slit die that freely moves in the width direction (TD) of the coating liquid support 32. By adhering to the thickness and drying on the coating liquid support 32, a part of the organic solvent of the polyimide precursor solution is volatilized and a part of the polyimide precursor is imidized to have self-supporting properties. It can be performed by forming a polyimide precursor gel film, and then the polyimide precursor gel film may be peeled from the support. The structure that freely rotates in the width direction of the coating liquid support has the following functions. According to normal machining, even with a coating liquid support machined with high precision, the influence of the runout of the coating liquid support can be substantially eliminated by having a mechanism for rotating the slit die. .

  Contact guides 33 and 34 for maintaining a constant distance between the coating liquid support 32 and the slit die 31 are provided at both ends of the slit die 32, and the distance between the coating liquid support 32 and the slit die 31 is set to 10 μm. It can be adjusted between 1000 μm.

  As mentioned above, although the example of embodiment of the manufacturing apparatus of the polyimide film concerning this invention was demonstrated, this invention is not limited only to these embodiment, The knowledge of those skilled in the art within the range which does not deviate from the meaning of this invention. Based on this, the present invention can be carried out in a mode with various improvements, changes, and modifications.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to this. In addition, the measuring method and evaluation method of the characteristic in an Example and a comparative example are as follows. The results are shown in Table 1.

(1) Measurement of viscosity The polyimide precursor solution was allowed to stand in a hot water bath at 23 ± 1 ° C for 2 hours, and the viscosity was measured using a Brookfield viscometer LVT.

(2) Film thickness measurement and coefficient of variation (variation)
The film thickness was measured using an eddy current film thickness meter EDY-1000 manufactured by Sanko Electronic Laboratory. The coefficient of variation was determined to evaluate the variation in film thickness. The variation coefficient can be calculated by first calculating the standard deviation and the average film thickness from the measured film thickness, dividing the standard deviation by the average film thickness, and multiplying it by 100%.

(3) Measuring method of film tension The tension applied to the film was measured using a tension sensor MB05B manufactured by Nireco and a tension controller Model TC900V manufactured by Nireco. The measurement place was measured immediately before the firing step.

(4) Evaluation of edge breakage OK if there was no edge breakage / breakage, and NG if there was any edge breakage / breakage.

(5) Evaluation of film formation state If there was no defect such as cissing or cutting, and there was no defect in appearance such as wrinkles or twisting, it was determined as OK. When defects such as repellency and millet, and defects on appearance such as wrinkles and twists were confirmed even a little, it was judged as NG. Further, NG was also set when the film thickness variation coefficient was larger than 25%.

Into a 500 ml separable flask, 415 g of N-methyl-2-pyrrolidone (NMP) was placed, and 2.8336 g (0.21 mol) of paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetra Carboxylic anhydride (BPDA) 60.721 g (0.21 mol) was added and reacted at room temperature and normal pressure for 1 hour to obtain a polyimide precursor solution. At this time, the solid content was 17% by weight and the viscosity was 1000 Ps.
The polyimide film manufacturing apparatus shown in FIG. 1 was used. A slit die provided with a contact guide in which the distance between the coating solution support and the slit die is adjusted to 80 μm is arranged so that the contact guide contacts the coating solution support, and the water is controlled with water controlled at 17 ± 2 ° C. While cooling the slit die, the prepared polyimide precursor solution was extruded at a rate of 100 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 10 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 5 μm and a film thickness variation coefficient of 10%.

A 500 ml separable flask was charged with 415 g of NMP, where 34.403 g (0.17 mol) of 4,4′-diaminodiphenyl ether (ODA) and 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride (BPDA) were added. ) 50.597 g (0.17 mol) was added and reacted at room temperature and normal pressure for 1 hour to obtain a polyimide precursor solution. At this time, the solid content was 17% by weight and the viscosity was 800 Ps.
The polyimide film manufacturing apparatus shown in FIG. 1 was used. A slit die provided with a contact guide in which the distance between the coating solution support and the slit die is adjusted to 80 μm is arranged so that the contact guide contacts the coating solution support, and the water is controlled with water controlled at 17 ± 2 ° C. While cooling the slit die, the prepared polyimide precursor solution was extruded at a speed of 50 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.7 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 7 μm and a film thickness variation coefficient of 9%.

In a 500 ml separable flask, 415 g of NMP was placed, and 40.670 g (0.203 mol) of 4,4′-diaminodiphenyl ether (ODA) and 43.444 g (0.199 mol) of pyromellitic dianhydride (PMDA) were added thereto. And reacted for 1 hour at room temperature and normal pressure to obtain a polyimide precursor solution. At this time, the solid content was 17% by weight and the viscosity was 1500 Ps.
The polyimide film manufacturing apparatus shown in FIG. 1 was used. A slit die provided with a contact guide in which the distance between the coating solution support and the slit die is adjusted to 90 μm is placed so that the contact guide contacts the coating solution support, and the water is controlled with water controlled at 17 ± 2 ° C. While cooling the slit die, the prepared polyimide precursor solution was extruded at a speed of 250 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 4 minutes on the support. Thereafter, the tension per unit cross-sectional area was 1.1 kgf / mm ² while the polyimide precursor gel film was brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 9 μm and a film thickness variation coefficient of 9%.

Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a rate of 100 mm / min and coated on the support while cooling the slit die with water controlled at 5 ± 1 ° C. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 10 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 200 ° C. and 330 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 8 μm and a film thickness variation coefficient of 10%.

Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. Then, while cooling the slit die with water controlled at 35 ± 2 ° C., the prepared polyimide precursor solution was extruded at a rate of 100 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 10 minutes on the support. Then, the tension per unit cross-sectional area was 0.2 kgf / mm ² while the polyimide precursor gel film was brought into contact with the heating roll with a roller heated to 250 ° C. and 380 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 6 μm and a film thickness variation coefficient of 13%.

Into a 500 ml separable flask, 415 g of N-methyl-2-pyrrolidone (NMP) was placed, and 2.8336 g (0.21 mol) of paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetra Carboxylic anhydride (BPDA) 60.721 g (0.21 mol) was added and reacted at room temperature and normal pressure for 1 hour to obtain a polyimide precursor solution. At this time, the solid content was 17% by weight and the viscosity was 4500 Ps.
A slit die provided with a contact guide in which the distance between the coating solution support and the slit die is adjusted to 80 μm is arranged so that the contact guide contacts the coating solution support, and the water is controlled with water controlled at 17 ± 2 ° C. While cooling the slit die, the prepared polyimide precursor solution was extruded at a speed of 50 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 6 μm and a film thickness variation coefficient of 13%.

Into a 500 ml separable flask, 415 g of N-methyl-2-pyrrolidone (NMP) was placed, and 2.8336 g (0.21 mol) of paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetra Carboxylic anhydride (BPDA) 55.118 g (0.19 mol) was added and reacted at room temperature and normal pressure for 1 hour to obtain a polyimide precursor solution. At this time, the solid content was 17% by weight and the viscosity was 75 Ps.
A slit die provided with a contact guide in which the distance between the coating solution support and the slit die is adjusted to 80 μm is arranged so that the contact guide contacts the coating solution support, and the water is controlled with water controlled at 17 ± 2 ° C. While cooling the slit die, the prepared polyimide precursor solution was extruded at a speed of 50 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 6 μm and a film thickness variation coefficient of 12%.

Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with a contact guide in which the distance between the coating solution support and the slit die is adjusted to 70 μm. The prepared polyimide precursor solution was extruded at a speed of 50 mm / min while being cooled on the slit die with water controlled at 17 ± 2 ° C. and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 55 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 5 μm and a film thickness variation coefficient of 10%.

Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a rate of 250 mm / min while being applied to the support while cooling the slit die with water controlled at 17 ± 2 ° C. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 10 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 5 μm and a film thickness variation coefficient of 13%.

Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a speed of 500 mm / min and applied onto the support while cooling the slit die with water controlled at 17 ± 2 ° C. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 2 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 7 μm and a film thickness variation coefficient of 10%.

The same PPD / BPDA polyimide precursor solution as in Example 1 was used. Using a device that uses a distance sensor for the distance adjustment mechanism, set the distance sensor so that the distance between the coating solution support and the slit die is 80 μm, and cool the slit die with water controlled at 17 ± 2 ° C. However, the prepared polyimide precursor solution was extruded at a speed of 100 mm / min and applied onto the support. At this time, the slit die has a drive mechanism that freely moves in the coating width direction, and the distance sensor detects the fluctuation so that the distance between the coating liquid support and the slit die is always within ± 5% of the predetermined distance. It is linked with the drive mechanism. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 10 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The film formation state of the obtained polyimide film was good, and there were no defects such as cracks at both ends of the film and in the film. This polyimide film had an average film thickness of 7 μm and a film thickness variation coefficient of 10%.

(Comparative Example 1)
Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a rate of 100 mm / min and applied onto the support while cooling the slit die with water controlled at 17 ± 2 ° C. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 20 minutes on the support. Thereafter, while holding both ends of the polyimide film with a pin tenter, the polyimide film was conveyed into a furnace maintained at 230 ° C. and 350 ° C. and baked.
As a result, stress concentration occurred in the portion held by the pin during film conveyance, and the film was torn with that portion as a base point, and the target polyimide film could not be obtained.

(Comparative Example 2)
Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a rate of 100 mm / min and applied onto the support while cooling the slit die with water controlled at 17 ± 2 ° C. At this time, it was regulated so as not to rotate freely with respect to the coating width direction of the slit die. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The resulting polyimide film was very uneven in film thickness. Clearly, one end was thick and the other end was thin, and wrinkles were found in the thin part. The average film thickness was 5 μm and the film thickness variation coefficient was 80%.

(Comparative Example 3)
Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a rate of 100 mm / min and applied onto the support while cooling the slit die with water controlled at 17 ± 2 ° C. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area was 1.2 kgf / mm ² while the polyimide precursor gel film was brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
As a result, the film was broken during firing due to the tension during film conveyance, and the intended polyimide film could not be obtained.

(Comparative Example 4)
Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a speed of 100 mm / min and applied onto the support while cooling the slit die with water controlled at 0 ± 1 ° C. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 10 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The state of the obtained polyimide film was extremely uneven in film thickness, and a thick part and a thin part were mixed. Longitudinal streaks due to poor application were partially observed. The average film thickness was 5 μm and the film thickness variation coefficient was 55%.

(Comparative Example 5)
Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. Then, while cooling the slit die with water controlled at 40 ± 2 ° C., the prepared polyimide precursor solution was extruded at a rate of 100 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 10 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The state of the obtained polyimide film was extremely uneven in film thickness, and a thick part and a thin part were mixed. Longitudinal streaks due to poor application were partially observed. The average film thickness was 7 μm, and the film thickness variation coefficient was 60%.

(Comparative Example 6)
Into a 500 ml separable flask, 415 g of N-methyl-2-pyrrolidone (NMP) was placed, and 2.8336 g (0.21 mol) of paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetra Carboxylic anhydride (BPDA) 60.721 g (0.21 mol) was added and reacted at room temperature and normal pressure for 1 hour to obtain a polyimide precursor solution. At this time, the solid content was 17% by weight and the viscosity was 5250 Ps.
A slit die provided with a contact guide in which the distance between the coating solution support and the slit die is adjusted to 80 μm is arranged so that the contact guide contacts the coating solution support, and the water is controlled with water controlled at 17 ± 2 ° C. While cooling the slit die, the prepared polyimide precursor solution was extruded at a speed of 50 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The state of the obtained polyimide film was extremely uneven in film thickness, and a thick part and a thin part were mixed. Longitudinal streaks due to poor application were partially observed. The average film thickness was 11 μm, and the film thickness variation coefficient was 80%.

(Comparative Example 7)
Into a 500 ml separable flask, 415 g of N-methyl-2-pyrrolidone (NMP) was placed, and 2.8336 g (0.21 mol) of paraphenylenediamine (PPD) and 3,3 ′, 4,4′-biphenyltetra Carboxylic anhydride (BPDA) 55.118 g (0.19 mol) was added and reacted at room temperature and normal pressure for 1 hour to obtain a polyimide precursor solution. At this time, the solid content was 17% by weight and the viscosity was 45 Ps.
A slit die provided with a contact guide in which the distance between the coating solution support and the slit die is adjusted to 80 μm is arranged so that the contact guide contacts the coating solution support, and the water is controlled with water controlled at 17 ± 2 ° C. While cooling the slit die, the prepared polyimide precursor solution was extruded at a speed of 50 mm / min and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 90 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The state of the obtained polyimide film was extremely uneven in film thickness, and a thick part and a thin part were mixed. Longitudinal streaks due to poor application were partially observed. The average film thickness was 8.5 μm, and the film thickness variation coefficient was 45%.

(Comparative Example 8)
Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a speed of 50 mm / min while being cooled on the slit die with water controlled at 17 ± 2 ° C. and applied onto the support. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having a self-supporting property was obtained by heating and drying at 40 ° C. for about 20 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The state of the obtained polyimide film was extremely uneven in film thickness, and a thick part and a thin part were mixed. Longitudinal streaks due to poor application were partially observed. The average film thickness was 9 μm and the film thickness variation coefficient was 80%.

(Comparative Example 9)
Using the same PPD / BPDA polyimide precursor solution as in Example 1, the contact guide is in contact with the coating solution support with the slit die provided with the contact guide with the distance between the coating solution support and the slit die adjusted to 80 μm. The prepared polyimide precursor solution was extruded at a rate of 250 mm / min while being applied to the support while cooling the slit die with water controlled at 17 ± 2 ° C. At this time, the slit die was allowed to freely rotate in the coating width direction. A polyimide precursor gel film having self-supporting property was obtained by heating and drying at 200 ° C. for about 4 minutes on the support. Thereafter, the tension per unit cross-sectional area is 0.2 kgf / mm ² while the polyimide precursor gel film is brought into contact with the heating roll with a roller heated to 230 ° C. and 350 ° C. so as to be in contact with the surface of the heating roll. And then fired.
The state of the obtained polyimide film was extremely uneven in film thickness, and a thick part and a thin part were mixed. Longitudinal streaks due to poor application were partially observed. The average film thickness was 9 μm and the film thickness variation coefficient was 65%.

Polyimide film manufacturing apparatus showing an example of the present invention Polyimide precursor solution coating mechanism showing an example of the present invention (top view) Polyimide precursor solution coating mechanism showing an example of the present invention (side view)

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Drying process 11 Slit die 12 Coating liquid support body 13 Polyimide precursor gel film 14 Conveyance roller 15 Firing process 16 First heating roll 17 Second heating roll 18 First nip roller 19 Second nip roller 20 Cooling process 21 Cooling roller 31 Slit die 32 Coating liquid support 33 Contact guide 34 Contact guide 35 Rotating shaft 36 Slit die holder 37 Air cylinder

Claims (10)

A device for producing a polyimide film by continuously applying a polyimide precursor solution from a slit die onto a support, followed by heating imide conversion,
The apparatus includes a slit die, a coating solution support for a polyimide precursor solution, and a heating imide conversion device,
An apparatus for producing a polyimide film, comprising an interval adjusting mechanism for maintaining a constant interval between a tip end portion of the slit die and the surface of the coating liquid support.   2. The polyimide film production according to claim 1, wherein the distance adjusting mechanism includes a contact guide or a distance sensor for detecting a distance between a tip end portion of the slit die and the surface of the coating liquid support. apparatus.   The said coating liquid support body is a rotating drum, The polyimide film manufacturing apparatus in any one of Claims 1-2.   The said heating imide conversion apparatus is equipped with the polyimide film in any one of Claims 1-3 provided with the at least 1 heating roll for making a polyimide precursor gel film contact the roll surface and completing imide conversion. Manufacturing equipment.   The polyimide film manufacturing apparatus of Claim 4 with which the nip roller for making the said polyimide precursor gel film press-contact with the heating roll surface is provided.   The polyimide precursor solution is applied to the coating liquid support surface from the slit die while detecting the distance between the slit die tip and the coating liquid support surface by the contact guide or the distance sensor. The manufacturing method of the polyimide film using the polyimide manufacturing apparatus in any one.   The polyimide precursor gel film having a self-supporting property dried on the coating solution support is peeled off from the coating solution support and led to the heating imide conversion device, and at least one having a surface temperature of 150 ° C. or more. The method for producing a polyimide film according to claim 6, wherein the polyimide precursor gel film is brought into contact with the surface of the heated roll to cause imide conversion in a stepwise manner. The method for producing a polyimide film according to claim 7, wherein a tension applied to the polyimide precursor gel film is 1.1 kgf / mm ² or less.   The polyimide film manufactured by the manufacturing apparatus in any one of Claims 1-5, and the method in any one of Claims 6-8.   The polyimide film according to claim 9, which has a thickness of 1 μm or more and 10 μm or less.