JP2014148126A - Method for producing polyimide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyimide film, which solves such problems that when the polyimide film containing a pigment and the like added thereto is continuously produced, a cleaning operation at product changeovers is complicated and a component other than a target component is mixed, and also produces the film having uniform quality.SOLUTION: The method for producing the polyimide film comprises the steps of: sending a polyamic acid solution, a dispersion of an insoluble additive and a hardening agent from different pipes respectively; mixing them; and extruding the mixture from a die.

Description

  The present invention relates to a method for producing a polyimide film, and more particularly to a method for producing a polyimide film that can be suitably used for continuous production of a polyimide film containing an insoluble additive such as a pigment.

  Since polyimide films have excellent heat resistance and insulation properties, they are used as base films for various flexible printed wiring boards, coverlays used to protect printed boards, and the like. As such a polyimide film, in recent years, a polyimide film containing a pigment has been manufactured for the purpose of changing surface properties and hue.

  When such a pigment-containing polyimide film is continuously produced, generally, the pigment dispersion is added to the polyimide precursor solution, and after sufficiently mixed in advance with a stirring blade or a planetary mixer, the resulting mixture is obtained. Is supplied to a die through piping, and extruded from the die to be molded. Such a method is disclosed as a method for producing a polyimide film containing inorganic particles such as a filler (see Patent Documents 1 to 3).

  That is, in Patent Document 1, in the production of a polyimide film containing inorganic particles, the inorganic particles are dispersed directly in an organic solvent or a solution containing an organic solvent, and directly added to the polyamic acid solution in the polymerization tank, followed by curing. A method of mixing an agent and extruding from a T-die is disclosed. Further, Patent Document 2 discloses a method for producing a polyimide film in which inorganic particles are dispersed in a film, and an inorganic particle slurry is added during or after polyamic acid polymerization, followed by decyclization and desolvation. Have been described. Patent Document 3 discloses a method for producing a polyimide film containing inorganic particles in the film. In the examples, after adding an inorganic particle slurry during or after polyamic acid polymerization, an imidization accelerator is added. And extruding from a T die.

JP 2011-1439 A (published January 6, 2011) JP 2008-106141 A (published May 8, 2008) JP 2008-7631 A (published January 17, 2008)

  However, in the above conventional production method, for example, when producing a small amount of various types of polyimide films with various adjustments of pigment types, combinations, addition amounts, etc. There are problems such as contamination. In addition, when a plurality of pigments are mixed in advance with the polyimide precursor solution, there is a problem that unevenness occurs in the sedimentation rate of the pigment in the storage tank, resulting in non-uniform product quality. Similar problems can occur not only in pigments but also in continuous production of polyimide films containing insoluble additives in general.

  The present invention has been made in view of the above-mentioned problems, and the purpose thereof is, when continuously producing a polyimide film containing an insoluble additive such as a pigment, the complexity of the cleaning operation at the time of product type switching, An object of the present invention is to provide a method for producing a polyimide film which does not have a problem of mixing of unintended components. Another object of the present invention is to provide a method for producing a polyimide film capable of producing a film of uniform quality when continuously producing a polyimide film containing an insoluble additive such as a pigment. is there.

  In order to solve the above problems, a method for producing a polyimide film according to the present invention is a method for continuously producing a polyimide film containing an insoluble additive, and includes at least an aromatic diamine and an aromatic dianhydride. The polyamic acid obtained by reacting the product, an insoluble additive, and a curing agent are mixed to form a resin solution. The resin solution is extruded from a die, cast onto a support, dried, and made into a gel film. A film process, and an imidization process in which the gel film obtained by the film formation process is baked and imidized. In the film formation process, a polyamic acid solution, a dispersion of insoluble additives, and a curing agent are used. These are characterized in that they are fed from different pipes, mixed, and extruded from a die.

  According to said structure, there exists an effect that there is no problem of the complexity of the washing | cleaning operation | work at the time of type | mold changeover, and the mixing of an unintended component. In addition, when a polyimide film containing an insoluble additive such as a pigment is continuously produced, it is possible to produce a film having a uniform quality.

  In the method for producing a polyimide film according to the present invention, the polyamic acid solution, the dispersion of the insoluble additive, and the curing agent are connected to the mixer via separate pipes respectively connected to the mixer installed immediately before the die. It is preferable that the solution is fed and mixed and extruded from a die.

  As a result, there is an effect that there is no problem of a complicated cleaning operation at the time of product type switching and a problem of mixing unintended components. In addition, when a polyimide film containing an insoluble additive such as a pigment is continuously produced, it is possible to produce a film having a uniform quality.

  In the method for producing a polyimide film according to the present invention, it is preferable that the outlet of the mixer is directly connected to a die.

  Thereby, since the resin solution immediately after being mixed with the mixer is extruded from the die in a more uniform state, there is an additional effect that a film with a more uniform quality can be continuously produced.

  In the method for producing a polyimide film according to the present invention, the content of the insoluble additive contained in the resin solution is preferably 1% by weight or more based on the total weight of the polyamic acid solid content.

  In the above case, the present invention works more effectively because the troubles such as the washing operation at the time of switching the product type, the problem of mixing of non-target pigments, and the problem of uneven quality are more remarkable.

  In the method for producing a polyimide film according to the present invention, the insoluble additive is preferably a pigment.

  In the above case, the present invention works more effectively because the troubles such as the washing operation at the time of switching the product type, the problem of mixing of non-target pigments, and the problem of uneven quality are more remarkable.

  The method for producing a polyimide film according to the present invention is a method for continuously producing a polyimide film containing an insoluble additive as described above, wherein at least an aromatic diamine and an aromatic dianhydride are reacted. A polyamic acid obtained in the above, an insoluble additive, and a curing agent to obtain a resin solution, which is extruded from a die, cast onto a support, dried, and formed into a gel film; An imidization step in which the gel film obtained by the film formation step is baked and imidized, and in the film formation step, the polyamic acid solution, the insoluble additive dispersion, and the curing agent are separately provided. Since it has a structure that feeds and mixes liquid from the pipe and pushes it out from the die, there is no problem of troublesome washing work at the time of product changeover and mixing of unintended components. To. In addition, when a polyimide film containing an insoluble additive such as a pigment is continuously produced, it is possible to produce a film having a uniform quality.

It is a figure which shows typically an example of the manufacturing apparatus used in this invention.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to this, and can be implemented in a mode in which various modifications are made within the described range.

  Unless otherwise specified in this specification, “A to B” indicating a numerical range means “A or more and B or less”.

  The method for producing a polyimide film according to the present invention is a method for continuously producing a polyimide film containing an insoluble additive, and a polyamic acid obtained by reacting an aromatic diamine and an aromatic dianhydride; An insoluble additive and a curing agent are mixed to obtain a resin solution. The resin solution is extruded from a die, cast onto a support, dried, and formed into a gel film. An imidization process in which the gel film is baked and imidized, and in the film forming process, the polyamic acid solution, the dispersion of the insoluble additive, and the curing agent are respectively fed from separate pipes. It is mixed and extruded from a die.

(I) Film-forming step In the film-forming step, at least a polyamic acid obtained by reacting an aromatic diamine and an aromatic dianhydride, an insoluble additive, and a curing agent are mixed to form a resin solution, The resin solution is extruded from a die, cast onto a support and dried to obtain a gel film.

<Insoluble additive>
Here, the insoluble additive is not particularly limited as long as it is insoluble in the solvent or dispersion medium used in the resin solution. The particle size of such particles is not particularly limited, but for example, the average particle size is about 0.01 μm to 20 μm.

  Examples of the insoluble additive include organic or inorganic pigments and fillers. Although it does not specifically limit as said organic pigment, For example, perylene black, paliogen black, aniline black, a polyimide powder etc. can be mentioned. Although it does not specifically limit as said inorganic pigment, For example, minerals, such as single or complex metal oxides, hematite, such as iron, manganese, chromium, titanium, carbon black, etc. are mentioned. In the present invention, the pigment includes, in addition to the insoluble additive used as a colorant, a bulking agent, a color developing agent, a compounding agent added for the purpose of controlling surface properties and hues, and the like. Examples of the filler include silica, mica, alumina, and titanium oxide used as a matting agent; boron nitride, aluminum nitride, and aluminum oxide used as a heat conductive filler. The filler also includes inorganic particles such as calcium phosphate and magnesium oxide that are added to adjust the surface properties.

  Specific examples of the polyimide film containing the pigment include a polyimide film containing perylene black and silica as the pigment. Here, the perylene black is not particularly limited, and examples thereof include BASF Rumogen Black. Perylene black is a black pigment exhibiting a purple color, and when it is generally colored with a yellow resin like a polyimide film, it can effectively appear black. Further, the silica is not particularly limited, and examples thereof include fused silica, fumed silica, synthetic silica and the like, or a combination of two or more thereof. Various HPS series manufactured by Electronics Co., Ltd .; SQ series manufactured by Hayashi Kasei Co., Ltd .; porous silica silicia series manufactured by Fuji Silysia, silo hovic series, and the like can be suitably used. By using silica, in the black polyimide film containing the perylene black, it is possible to obtain a polyimide film having both excellent light shielding properties and a matte texture and also having high insulation reliability.

  The content of the insoluble additive contained in the resin solution is not particularly limited, but is preferably 1% by weight or more, more preferably 2% by weight or more based on the total weight of the polyamic acid solid content. Particularly preferred is 3% by weight or more, and most preferred is 5% by weight or more. In particular, in a polyimide film containing a pigment, the content of the pigment contained is 1% by weight or more, compared with the content of additives such as inorganic particles added to a polyimide film containing conventional inorganic particles. Remarkably many. For this reason, problems such as the complexity of the washing operation when changing the product type and the mixing of unintended pigments are remarkable when the polyimide film is continuously produced. Therefore, in such a case, the production method of the present invention is particularly effective.

  Here, the content of the insoluble additive is calculated from the weight of the equimolar amounts of aromatic diamine and aromatic dianhydride used in the polymerization step and the weight of the added insoluble additive. can do. Further, the content of the insoluble additive in the obtained polyimide film is not particularly limited, but is more preferably 1% by weight or more, further preferably 2% by weight or more, and particularly preferably 3%. % By weight or more, most preferably 5% by weight or more. The content of the insoluble additive in the obtained polyimide film can be measured as follows. That is, it can be measured by dissolving the polyimide film using a hydrazine solution, filtering, washing and drying, and then measuring the weight and comparing it with the weight of the film before treatment.

<Polyamide acid>
The polyamic acid is obtained by reacting an aromatic diamine and an aromatic dianhydride. More specifically, usually, the aromatic diamine and the aromatic dianhydride are dissolved in an organic solvent so as to have a substantially equimolar amount, and the resulting solution is subjected to controlled temperature conditions. Under stirring, it is produced by stirring until the polymerization of the acid dianhydride and the diamine is completed. The solution containing the polyamic acid thus obtained is usually obtained at a concentration of 5 to 35% by weight, more preferably 10 to 30% by weight. When the concentration is in this range, an appropriate molecular weight and solution viscosity are obtained.

  Examples of the aromatic diamine include, but are not limited to, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 2,2-bis {4 -(4-aminophenoxy) phenyl} propane, 2,2-bis {4- (4-aminophenoxy) phenyl} hexafluoropropane, bis {4- (3-aminophenoxy) phenyl} sulfone, bis {4- ( 4-aminophenoxy) phenyl} sulfone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 3, 3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-dichlorobenzidine, 3,3 -Dimethylbenzidine, 2,2'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 2,2'-dimethoxybenzidine, 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene (m- Phenylenediamine), 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 9,9-bis (4-aminophenyl) fluorene, 4,4 ′-(1,4-phenylenebis (1- Methylethylidene)) bisaniline, 4,4 ′-(1,3-phenylenebis (1-methylethylidene)) bisaniline, 4,4′-diaminobenzanilide and the like, or a combination of two or more of these. .

  In addition, the aromatic acid dianhydride is not limited to this. For example, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 2,2 ′, 3,3 '-Benzophenone tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 3,4'-oxyphthalic dianhydride, ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (tri Meritic acid monoester anhydride), pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 3, 3 ', 4,4'-diphenylsulfonetetracarboxylic dianhydride, 3,3', 4,4'-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ', 4,4'-tetraphenyl Lantetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 4,4'- Hexafluoroisopropylidenediphthalic anhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, p-phenylenebis (Trimellitic acid monoester anhydride), aromatic tetracarboxylic dianhydride such as p-phenylenediphthalic anhydride, or a combination of two or more of these.

  The aromatic diamine and the aromatic dianhydride may be reacted so as to have a substantially equimolar amount, and the order of addition, the combination of monomers, and the composition are not particularly limited. .

  The organic solvent used as the polymerization solvent for producing the polyamic acid is not particularly limited as long as it dissolves the aromatic diamine component, the aromatic dianhydride component, and the resulting polyamic acid. . If, for example, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone, N, N-dimethylacetamide or the like is used as the polymerization solvent, the resulting polyamic acid solution is used as it is. It can be set as the polyamic acid solution mentioned later.

  The reaction temperature for producing the polyamic acid is preferably −10 ° C. to 50 ° C. Within such a range, the reaction proceeds at a good reaction rate and is excellent in productivity, which is preferable. The reaction time is not particularly limited, but is usually from several minutes to several hours.

<Curing agent>
In the present invention, the curing agent includes a dehydrating agent and a catalyst.

  Here, the dehydrating agent is not particularly limited as long as it is a dehydrating ring-closing agent for polyamic acid. For example, aliphatic acid anhydride, aromatic acid anhydride, N, N′-dialkylcarbodiimide, lower aliphatic Listed are halides, halogenated lower aliphatic acid anhydrides, aryl sulfonic acid dihalides, thionyl halides, and the like. These may be used alone or in appropriate combination of two or more. Among these, aliphatic acid anhydrides and / or aromatic acid anhydrides can be particularly preferably used. The content of the dehydrating agent contained in the resin solution is not particularly limited, but is preferably in the range of 0.5 to 5 moles per mole of amic acid unit contained in the polyamic acid. More preferably within the range of 7 to 4 mol, particularly preferably within the range of 1.5 to 2.5 mol.

  The catalyst is not particularly limited as long as it is a component having an effect of promoting the dehydration ring-closing action of the dehydrating agent on the polyamic acid. Specifically, for example, aliphatic tertiary amine, aromatic Group tertiary amines, heterocyclic tertiary amines and the like can be mentioned. Among these, for example, nitrogen-containing heterocyclic compounds such as imidazole, benzimidazole, isoquinoline, quinoline, diethylpyridine, and β-picoline are particularly preferably used. The content of the catalyst contained in the resin solution is not particularly limited, but is preferably in the range of 0.05 to 3 moles per mole of amic acid unit contained in the polyamic acid. A range of 2 to 2 mol is more preferable, and a range of 0.5 to 1 mol is particularly preferable.

  When the usage-amounts of the said dehydrating agent and a catalyst are in the said range, the gelatinization reaction at the time of making the said resin solution into a liquid film and drying can be accelerated | stimulated suitably.

<Mixing of polyamic acid, insoluble additive, and curing agent>
In the present invention, the polyamic acid, the insoluble additive, and the curing agent are mixed by feeding and mixing the polyamic acid solution, the dispersion of the insoluble additive, and the curing agent from separate pipes. .

  Here, the polyamic acid solution may be a solution containing the above-described polyamic acid. The solvent used in the polyamic acid solution is not particularly limited as long as it is an organic solvent that dissolves polyamic acid. For example, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide; N, N-dimethylformamide, Formamide solvents such as N, N-diethylformamide; Acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide; Pyrrolidone systems such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone Solvents; phenol solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, catechol; ether solvents such as tetrahydrofuran, dioxane, dioxolane; alcohol solvents such as methanol, ethanol, butanol; Spotted Organic polar solvents such as cellosolve solvents such as lucerosolve; solvents such as hexamethylphosphoramide and γ-butyrolactone; These organic solvents may be used alone or in combination of two or more. Furthermore, aromatic hydrocarbons such as xylene and toluene can also be used. Among the above organic solvents, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide can be particularly preferably used. For example, when N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone or the like is used as a solvent for polymerization of polyamic acid, the polyamic acid obtained by polymerization This solution can be used as it is as a polyamic acid solution. Alternatively, the polymerization solvent contained in the solution obtained after the polyamic acid polymerization may be replaced with the above solvent and used as a polyamic acid solution.

  The concentration of the polyamic acid in the polyamic acid solution is usually 5 to 35% by weight, more preferably 10 to 30% by weight. When the concentration is in this range, an appropriate solution viscosity is obtained.

  The dispersion of the insoluble additive may be a dispersion containing the above-described insoluble additive. In the present invention, one type of dispersion may be used as the dispersion of the insoluble additive, or two or more types of dispersion may be used. Examples of using two or more types of dispersions include, for example, the case where each insoluble additive is prepared as a separate dispersion in order to produce a polyimide film containing two or more types of insoluble additives. . In such a case, the two or more kinds of dispersion liquids separately adjusted, the polyamic acid solution, and the curing agent may be fed from different pipes and mixed. As a result, when switching to a variety in which the type, combination, addition amount, ratio, etc. of two or more insoluble additives are changed, there is no complication of washing work at the time of changing the type, and the product is continuously transferred to a different type. Is possible.

  As an example of a combination of two or more types of insoluble additives, for example, a case where a plurality of pigments are combined as described above can be mentioned.

  Further, one dispersion may contain one type of insoluble additive or two or more types of insoluble additives. When one type of insoluble additive is contained in one dispersion, there is no complication of washing work when changing the type when changing the type of each insoluble additive, etc. It becomes possible to shift to different varieties. However, the insoluble additive contained in one dispersion is not necessarily limited to one type, and two or more types of the insoluble additives described above may be used depending on the type of the target polyimide film, the production plan, and the like. It may be a combination.

  The content of the insoluble additive contained in the dispersion of the insoluble additive is preferably 1 to 30% by weight, more preferably 4 to 20% by weight, based on the total weight of the dispersion. . If the content of the insoluble additive contained in the dispersion of the insoluble additive is within the above range, it is preferable because it falls within the easy-to-handle viscosity range and there is little deterioration in quality due to aggregation or sedimentation.

  The dispersion medium used in the dispersion of the insoluble additive is not particularly limited as long as it is a liquid capable of dispersing the insoluble additive and does not decompose the polyamic acid or inhibit the imidization reaction. Although not intended, for example, a solvent used for the polyamic acid solution can be preferably used. The dispersion medium may be the same as or different from the solvent used for the polyamic acid solution.

  The dispersion of the insoluble additive can be obtained by a method of suspending the insoluble additive in the dispersion medium. The dispersion method is not particularly limited. For example, a known dispersion technique such as ball mill, bead mill, three-roll, homogenizer, ultrasonic, stirring blade, high shear mixer, disperser or the like is suitable. Can be used.

  The curing agent to be mixed with the polyamic acid solution and the dispersion of the insoluble additive is as described above. However, if the curing agent is not a liquid that can be sent via a pipe, it may contain a solvent. Such a solvent is not particularly limited, and for example, a solvent used for the polyamic acid solution can be suitably used.

  In the present invention, the polyamic acid solution, the dispersion of the insoluble additive, and the curing agent may be sent from different pipes and mixed, but the polyamic acid solution, the dispersion of the insoluble additive, and An example of mixing the curing agent will be described below with reference to FIG. FIG. 1 schematically shows an example of a production apparatus used in the method for producing a polyimide film according to the present invention. In the production apparatus shown in FIG. 1, the polyamic acid solution, the dispersion of the insoluble additive, and the curing agent are the polyamic acid solution storage tank 3, the insoluble additive dispersion storage tanks 4, 5, and the curing, respectively. It is supplied from the agent storage tank 6. All of these storage tanks are connected to the mixer 2 or the dice 1 through separate pipes respectively connected to the mixer 2 installed immediately before the dice 1.

  Then, the polyamic acid solution, the dispersion of the insoluble additive, and the curing agent are sent to the mixer via separate pipes respectively connected to the mixer 2 installed immediately before the die 1, The resin solution mixed by the mixer and obtained by mixing is extruded from the die 1.

  The die 1 is provided with a supply port part to which the resin solution is continuously supplied from the mixer 2 at the upper part thereof. Further, the die 1 is provided with a lip opening at a lower portion thereof for continuously extruding the supplied resin solution with a predetermined width and thickness. Therefore, the resin solution continuously flows through the inside of the die 1 from the supply port toward the lip opening (arrow direction in FIG. 1).

  Here, the mixer 2 only needs to be installed immediately before the dice 1. Here, the mixer 2 is installed just before the dice 1. The mixer 2 is a polyamic acid solution, a dispersion of insoluble additives, and a curing agent. It is only necessary that the resin solution obtained by mixing is supplied to the die 1 as it is. That is, the resin solution obtained by the mixer 2 may be supplied to the dice 1 without adding further components, but the outlet of the mixer 2 and the supply port of the dice 1 However, it is particularly preferable that they are directly connected without a pipe. Thereby, since the resin solution immediately after mixing is extruded from the die 1 in a more uniform state, a film with a more uniform quality is continuously produced even when an insoluble additive such as a pigment is included. be able to.

  The flow rate when the polyamic acid solution, the dispersion of the insoluble additive, and the curing agent are respectively sent to the mixer via separate pipes is not particularly limited, using a pump or the like, What is necessary is just to adjust suitably according to a mixing ratio or the density | concentration of a solution or a dispersion liquid.

  The specific configuration of the mixer 2 is not particularly limited, and a conventionally known mixer is suitably used as long as it has a means capable of mixing a polyamic acid solution, a dispersion of an insoluble additive, and a curing agent. Can be used. Examples of such means include a stirring blade, a static mixer, and a pin mixer.

  Moreover, the specific structure of the dice | dies 1 is not specifically limited, either a conventionally well-known dice | dies can be used suitably.

  The specific configuration of the storage tanks 3 to 6 is not particularly limited, and a conventionally known tank can be suitably used. The same applies to the piping, and conventionally known pipes can be suitably used. The size and material of these tanks and pipes are appropriately set depending on the production scale, the type of polyimide film to be produced, detailed production conditions, etc., and are not particularly limited.

  In addition, although it is more preferable that the discharge port of the mixer 2 and the supply port part of the die 1 are directly connected, it is not always necessary to connect directly, and a uniform resin solution is extruded from the die 1. If it can do, it may be connected via piping. In such a case, the length of the pipe connecting the discharge port of the mixer 2 and the supply port portion of the die 1 is preferably 500 cm or less, and more preferably 300 cm or less.

  In the above example, the polyamic acid solution storage tank 3, the insoluble additive dispersion storage tanks 4 and 5, and the curing agent storage tank 6 are provided, but the types and number of storage tanks are limited thereto. For example, the number of dispersion liquid storage tanks may be one, or three or more. Two or more polyamic acid solution storage tanks may be provided, or two or more curing agent storage tanks may be provided.

  Furthermore, the die is not limited to a single layer extrusion die, and may be a multilayer coextrusion die.

<Other ingredients>
In the present invention, at least the polyamic acid, the insoluble additive, and the curing agent may be mixed to form a resin solution, but the resin solution may further contain other components. Although it does not specifically limit as another component, For example, an adhesion imparting agent, a storage stabilizer, an ion scavenger, etc. can be mentioned. In addition, the resin solution may contain polyimide as long as it can be dissolved. These other components may be supplied to the mixer and mixed with the polyamic acid, the insoluble additive, and the curing agent, or may be previously contained in the polyamic acid, the insoluble additive, or the curing agent. Also good.

<Film formation>
In the film forming step, at least polyamic acid, an insoluble additive, and a curing agent are mixed to form a resin solution, the resin solution is extruded from a die, cast onto a support, and dried to form a gel film. . That is, in this step, by drying the cast liquid film made of the resin solution, the solvent is evaporated and imidization proceeds to some extent to obtain a gel film having self-supporting properties.

  What is necessary is just to select suitably about the solvent residual rate in the state of a gel film, the degree of imidation, and the temperature setting of drying according to the kind of polyamic acid, the thickness of the polyimide film obtained, etc. That is, the method and conditions for obtaining the gel film are not particularly limited, and may be any conditions that can partially convert the solvent from the liquid film or imidize part of the polyamic acid to convert it into a gel film. That's fine. Usually, a drying method by heating or the like can be employed. In this case, the drying on the support is preferably performed by heating in a temperature range of 60 ° C. to 200 ° C., more preferably 80 ° C. to 150 ° C. Thereby, the conversion to a gel film can be suitably advanced, and the remaining components can be effectively evaporated at the initial stage of drying, which is preferable. Moreover, it does not specifically limit about a heating method, A conventionally well-known heating method can be used suitably.

  Also, the drying time is not particularly limited, but is preferably within the range of 1 to 600 seconds. If a heating time is in the said range, a gel film can be produced efficiently.

  Although it does not specifically limit as a support body used in this process, The rotating drum, an endless belt, etc. can be used suitably from a viewpoint of manufacturing a polyimide film continuously. The material of the support is not particularly limited as long as it is a metal, resin, or the like. For example, a metal such as stainless steel is more preferable, and a stainless steel drum, a stainless steel endless belt, and the like are particularly preferable. Can be used. For example, this step may be performed by casting the resin solution in a drying furnace, preferably on a heated support.

  In addition, in the said description, although the manufacturing method of the single layer polyimide film was shown, the manufacturing method which concerns on this invention is not limited to the manufacturing method of a single layer polyimide film, A multilayer polyimide film is manufactured. In this case, it can be suitably used. In such a case, as a method for producing a multilayer film, a conventionally known method for producing a multilayer film can be appropriately selected and used.

  Moreover, the manufacturing method of the polyimide film which concerns on this invention should just be a manufacturing method of a polyimide film, and the polyimide film obtained is a thermoplastic polyimide, a non-thermoplastic polyimide, or those copolymers. It doesn't matter if it is.

(II) Imidization process In the imidization process, the gel film obtained by the film forming process is baked to perform imidization. The imidization method is not particularly limited, but more preferably, the gel film obtained by the film forming step is peeled off from the support, the ends are fixed, and the film is baked in a baking furnace. That is, in this step, the gel film obtained in the film forming step is peeled off from the support, and the removal of the remaining solvent and imidization are completed through a baking furnace with both ends in the width direction of the film fixed. By doing so, a polyimide film is obtained.

  Here, as the baking furnace used in the present invention, a conventionally known baking furnace can be suitably used, and is not particularly limited. For example, the gel film is fixed by fixing both ends of the gel film with clips or tenter pins. It is more preferable to use a type that conveys to a heating and baking furnace.

  More specifically, for example, both ends of the gel film peeled off from the support are pierced and fixed by needle-like fixing means called tenter pins. The immobilized gel film is supported in a spread state, and in this state, the gel film is carried into a firing furnace and baked. Since the baking of the gel film is completed and the polyimide film is obtained by being completely imidized, the polyimide film is pulled out from the tenter pin and collected. Further, as the fixing means, for example, fixing means other than a tenter pin such as a clip may be used.

  At this time, the method and conditions for obtaining the polyimide film by firing the gel film are not particularly limited, and any method or conditions may be used as long as the gel film can be effectively heated and fired into the polyimide film. A system in which hot air of 100 ° C. or more is sprayed on the entire film from the upper surface or the lower surface of the film, or a heating method, or a method of irradiating far infrared rays on the film can be suitably used. The firing temperature in the firing step is not particularly limited as long as imidization can be completed and the remaining components can be sufficiently evaporated, but is preferably 200 ° C to 600 ° C, and gradually. More preferably, the temperature is increased. The firing time is not particularly limited, and the firing can be performed within a conventionally known range as long as imidization can be completed.

  The total width of the polyimide film obtained by the imidization step is appropriately set according to the use of the film to be produced, etc., and is usually 500 mm to 3000 mm, more preferably 750 mm to 2500 mm.

  Moreover, the thickness of the polyimide film obtained by an imidation process is suitably set according to the use etc. of the film to manufacture, and is 5 micrometers-200 micrometers normally, More preferably, they are 7.5 micrometers-125 micrometers.

[III] Other Steps The method for producing a polyimide according to the present invention may include the film forming step and the imidization step, and further includes a step of winding the polyimide film obtained by the imidization step. May be.

  Moreover, the manufacturing method of the polyimide which concerns on this invention may further include the superposition | polymerization process which synthesize | combines the said polyamic acid.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by an Example.

[Example 1]
57 kg of 4-4′-diaminodiphenyl ether (hereinafter referred to as 4,4′-ODA) is added to 778 kg of N, N-dimethylformamide (hereinafter referred to as DMF) and dissolved therein. 82.8 kg of pyromellitic dianhydride (hereinafter referred to as PMDA) was gradually added and stirred for 30 minutes or more to obtain a prepolymer. To this prepolymer, 45 kg of a 20 wt% DMF solution of paraphenylenediamine was gradually added to increase the viscosity, thereby obtaining a 3500 poise polyamic acid solution.

  The obtained polyamic acid solution, a curing agent mixed in a ratio of DMF / acetic anhydride / isoquinoline = 16/4/9, and 7% by weight of BASF Rumogen Black FK4280 dispersed in DMF using a bead mill. The dispersion and a 16.5% by weight dispersion obtained by dispersing a porous silica silophobic 250 manufactured by Fuji Silysia in DMF using a bead mill were stored in storage tanks installed separately. As the manufacturing apparatus, an apparatus in which each storage tank is connected to a pin mixer installed immediately before the dice and a separate pipe is used.

  The porous silica silo hovic 250 dispersion at a flow rate of 57 kg / hour, the polyamic acid solution at a flow rate of 30 kg / hour, and the lumogen black FK4280 dispersion at a flow rate of 7.0 kg / hour. Is fed at a flow rate of 4.5 kg / hour using each pump and pipe, mixed in the pin mixer, immediately pushed out of the die, and traveled 25 mm below the die at a speed of 10 m / min. Cast on a stainless steel endless belt.

  After heating the obtained liquid film at 130 ° C. × 100 seconds, the self-supporting gel film is peeled off from the endless belt and fixed to the tenter pin, and continuously conveyed to a baking furnace at 230 ° C. × 30 seconds, 350 C. for 30 seconds and 450.degree. C. for 30 seconds to be imidized to obtain a 6000 m long film. When this film was observed, there was no difference in glossiness between the beginning of winding the long film, the portion wound 3000 m, and the portion wound 6000 m.

[Example 2]
In Example 1, after obtaining a 6000 m long film, the addition amount of a 16.5 wt% dispersion in which a porous silica silo hobic 250 made by Fuji Silysia was dispersed using a bead mill was changed. A long film of 6000 m could be obtained in the same manner as in Example 1 except that the amount was 5 kg / hour.

[Comparative Example 1]
To DMF777.7 kg, 88.6 kg of 4-4′ODA was added and dissolved, and 93.6 kg of PMDA was gradually added to this solution and stirred for 30 minutes or more to obtain a prepolymer. To this prepolymer, 115 kg of 7 wt% dispersion obtained by dispersing BASF Rumogen Black FK4281 in DMF using a bead mill and Fuji Silicia porous silica silicia 350 dispersed in DMF using a bead mill16. Then, 73 kg of a 5 wt% dispersion was added and stirred.

  The resulting pigment dispersion-added prepolymer was gradually added with 40 kg of a 7 wt% DMF solution of PMDA to increase the viscosity. After obtaining a 1200-poise pigment-dispersed polyamic acid solution, the mixture was cooled and stored in the tank.

  The obtained pigment-dispersed polyamic acid solution was continuously fed from a pump at 68 kg / hour, and a hardener mixed at a ratio of DMF / acetic anhydride / isoquinoline = 16/4/9 was added to another pipe at 30 kg / hour. Then, the mixture was mixed in a pin mixer installed immediately before the die, immediately extruded from the die, and cast on a stainless steel endless belt running 25 mm below the die at a speed of 10 m / min. The liquid film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt, fixed to the tenter pin, and continuously conveyed to a baking furnace at 230 ° C. for 30 seconds, 350 ° C. × 30. The film was baked at 450 ° C. for 30 seconds and imidized to obtain a 6000 m long film. When this film was observed, there was a difference in glossiness between the winding start part of the long film, the part wound 3000 m, and the part wound 6000 m. Moreover, since the dispersion liquid was contained in the varnish, the amount of addition could not be adjusted, and it was not possible to continuously obtain other products whose glossiness was changed during film formation.

  According to the present invention, even when a polyimide film to which pigments and the like are added is continuously produced, there is no trouble of washing work at the time of product changeover, and there is no problem of mixing of unintended components, and a film of uniform quality is produced. can do.

  Therefore, the method for producing a polyimide film according to the present invention includes various films represented by polyimide-containing films and laminates, such as base film of various printed boards, coverlay films used for protecting printed boards, and the like. It can be used in the field of producing resin molded products. Furthermore, it can be widely applied to fields related to the manufacture of electronic components using such films and laminates.

DESCRIPTION OF SYMBOLS 1 Dice 2 Mixer 3 Polyamic acid solution storage tank 4 Dispersion storage tank of insoluble additive 5 Dispersion storage tank of insoluble additive 6 Hardener storage tank

Claims (5)

A method for continuously producing a polyimide film containing an insoluble additive,
At least a polyamic acid obtained by reacting an aromatic diamine and an aromatic dianhydride, an insoluble additive, and a curing agent are mixed to form a resin solution, and the resin solution is extruded from a die, and a support is obtained. Casting up and drying to form a gel film,
An imidization step of firing and imidizing the gel film obtained by the film formation step,
A method for producing a polyimide film, characterized in that, in the film forming step, a polyamic acid solution, a dispersion of an insoluble additive, and a curing agent are fed from separate pipes, mixed, and extruded from a die.   The polyamic acid solution, the dispersion of the insoluble additive, and the curing agent are sent to the mixer through separate pipes connected to the mixer installed immediately before the die, mixed, and extruded from the die. The manufacturing method of the polyimide film of Claim 1 characterized by the above-mentioned.   3. The method for producing a polyimide film according to claim 2, wherein the discharge port of the mixer is directly connected to a supply port portion of a die.   Content of the said insoluble additive contained in the said resin solution is 1 weight% or more with respect to the polyamic-acid solid content total weight, The polyimide of any one of Claims 1-3 characterized by the above-mentioned. A method for producing a film.   The said insoluble additive is a pigment, The manufacturing method of the polyimide film of any one of Claims 1-4 characterized by the above-mentioned.

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