JP4796705B2 - Method for producing polyimide film - Google Patents

Description

【００３１】
【発明の効果】
以上のように、本発明は、硬化剤組成を調節することにより押出しダイ中の溶液粘度を低くすることにより、高速製膜における泡の巻き込みを防止し、ＭＤ方向の厚みムラの発生を防止しつつ、機械的特性の優れたポリイミドフィルムの製造方法を提供することができる。
【図面の簡単な説明】
【図１】ポリイミドフィルムの製造工程
【図２】流延製膜方法によりダイリップから押出されたカーテンの状態
【符号の説明】
２；押出し機
４；スリットダイ
６、２０；ダイリップ
８、２６；樹脂膜
１０、２４；コンベアベルト
２２；カーテン[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polyimide film by casting film formation such as a T-die method in extrusion molding. Specifically, in a T-die method or the like, a polyimide that has excellent mechanical strength and prevents bubble entrainment of a resin solution (referred to as a curtain in this specification) extruded from a die, and further prevents uneven thickness. The present invention relates to a film manufacturing method.
[0002]
[Prior art]
Polyimide is a plastic material that has excellent heat resistance, insulation, solvent resistance, and low temperature resistance, and is used as an electrical and electronic component material. Especially, it is a flexible printed wiring board and a carrier for TAB. Examples thereof include a tape base film, an electric wire coating for aircraft, a magnetic recording tape base film, a superconducting coil wire coating, and the like. For these various uses, a polyimide film suitable for each use is appropriately selected.
As electrical and electronic parts become smaller and thinner, circuits are becoming thinner, and dimensional changes in the components used may lead to failures such as disconnection and short circuits in the thinned circuit configuration. . Therefore, a member used for an electric / electronic component is required to have dimensional stability with high accuracy.
By the way, in the production of the polyimide film, the polyamic acid solution composition which is the polyimide precursor is mixed with the chemical imidizing agent solution in the extruder 2 as shown in FIG. After spreading, through a narrow slit-shaped gap of the slit die 4, it is continuously extruded onto a smooth thin film on an endless belt, solidified to the extent that it has self-supporting property by drying and cooling while proceeding with imidization, and thereafter Further, it is manufactured by a heat treatment method.
In addition, the polyamic acid composition, which is a precursor of polyimide, is subjected to film forming, heating, and drying by a casting method using a T-die to complete imidization to obtain a polyimide film. If the advancing proceeds rapidly, partial imidization occurs in the resin film, resulting in a gel-like defect in the film, or a partially imidized gel-like material clogging the slit die and causing coating stripes. In order to avoid this problem, it is effective to cool the polyamic acid solution composition to 0 ° C. or less as a method for controlling the imidization reaction, but for this reason, the viscosity of the polyamic acid solution composition tends to be particularly high. is there.
When the above-mentioned viscosity range, that is, such a resin solution composition having a relatively high viscosity is used, the resin solution composition has elasticity. Therefore, as shown in FIG. 2, the curtain 22 of the resin solution composition having fluidity extruded from the slit die 20 is pulled in the traveling direction as the belt speed increases. When the curtain 22 is pulled in the traveling direction, the landing angle sheet θ between the curtain 22 and the belt 24 of the take-up machine becomes small, and when the curtain 22 lands on the surface of the belt 24, it becomes easy to enclose surrounding air. .
As a result, air is sealed between the resin film 26 and the belt 24, and large and small bubble-shaped protrusions remain on the surface of the resin film 26. This entrainment phenomenon of bubbles is the cause of significant damage to the surface of the resin film, such as when the resin film is thinned or the entrained air expands to break the resin film and create a defective part in the resin film drying process. Become.
Further, the curtain having a high viscosity as described above has a higher elastic force than a curtain having a low viscosity and has a higher adhesive force to the belt, so that it is pulled in the traveling direction by the movement of the belt. However, if the curtain is pulled a certain distance in the direction of travel by the belt, a force opposite to the direction of travel acts due to the elastic force of the resin film, so that the landing point of the curtain fluctuates periodically. Due to this periodic variation, the thickness of the manufactured resin film varies, and as a result, periodic thickness unevenness occurs in the traveling direction, and there is a problem that the shape of the film as the final product appears as a striped pattern.
In order to solve this problem, Japanese Patent Application Laid-Open No. 11-198157 discloses a casting film forming method in which the viscosity in a die is lowered for the purpose of preventing bubble entrainment during casting of a resin film and improving thickness unevenness. is doing. And as a method for lowering the viscosity in the die, a method for lowering the degree of polymerization of the resin solution composition and a method for increasing the solvent ratio of the resin solution composition are raised.
However, the polyimide film obtained by the method for reducing the degree of polymerization disclosed in JP-A-11-198157 is compared with the polyimide film obtained from an equimolar amount of a diamine component and a tetracarboxylic dianhydride component. Mechanical properties are greatly reduced. Further, in the method for increasing the solvent ratio of the resin solution composition disclosed in JP-A-11-198157, it is necessary to increase the temperature of the belt greatly in order to dry it until it has self-supporting property on the endless belt, The mechanical properties of the resulting polyimide film are reduced.
As described above, the mechanical properties of the polyimide film obtained are greatly reduced in the film-forming method disclosed in JP-A-11-198157, which prevents entrainment of bubbles during casting of the resin film and improves thickness unevenness. ing. This decrease in mechanical properties is due to the elongation of the film in the manufacturing process of flexible printed wiring boards, TAB carrier tape base films, aircraft wire coatings, magnetic recording tape base films, superconducting coil wire coatings, etc. Occurrence of slack due to hinders stable production. In addition, the mechanical resistance of the product is lowered, and the reliability of the product is lowered.
[0003]
[Problems to be solved by the invention]
The present invention provides a casting film production method for producing a polyimide film at a high speed as described above, which prevents entrainment of bubbles during casting of the resin film, improves thickness unevenness, and is further disclosed in JP-A-11-198157. The present invention also provides a method for producing a polyimide film in which the deterioration of mechanical properties that occurs in the casting film forming method does not occur.
[0004]
[Means for Solving the Problems]
This invention was made in order to solve the said subject, The summary of the manufacturing method of the polyimide film is in the manufacturing method of the polyimide film which casts the composition containing a polyamic acid, and makes it a polyimide film In the organic solvent solution of polyamic acid, the molar ratio of the dehydrating agent and the imidization catalyst is 1: dehydrating agent of 1 molar equivalent or more with respect to amic acid and imidizing catalyst of 0.2 molar equivalent or more with respect to amic acid. It exists in adding the hardening | curing agent contained in the ratio of 0.15 to 1: 0.75.
[0005]
Moreover, the place made into the another summary of the manufacturing method of the polyimide film concerning this invention exists in adding 30-70 parts hardening | curing agent to the organic solvent solution of 100 parts polyamic acid in the manufacturing method of the said polyimide film. .
[0006]
Moreover, the place made into the other summary of the manufacturing method of the polyimide film concerning this invention is the manufacturing method of the said polyimide film, The resin solution composition formed by adding a hardening | curing agent to the organic solvent solution of a polyamic acid in 0 degreeC. The viscosity is 600 poise or less.
[0007]
Moreover, the place made into the other summary of the manufacturing method of the polyimide film concerning this invention is the manufacturing method of the said polyimide film, The resin solution composition formed by adding a hardening | curing agent to the organic solvent solution of a polyamic acid in 0 degreeC. The viscosity is 400 poise or less.
[0008]
Moreover, the place made into the other summary of the manufacturing method of the polyimide film concerning this invention exists in an imidation catalyst being a tertiary amine.
[0009]
Moreover, the place made into the other summary of the manufacturing method of the polyimide film concerning this invention is the polyimide film manufactured by the said method.
[0010]
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the method for producing a polyimide film according to the present invention will be described.
In addition, the term “curtain” of the present invention means that the resin solution composition having fluidity has a curtain-like shape that exists in the gap of the air gap until it is extruded from the slit die and landed on the belt. Say.
Basically, any known polyamic acid can be applied to the polyamic acid, which is a polyimide precursor used in the present invention.
[0012]
The polyamic acid used in the present invention is usually a polyamic acid organic solvent obtained by dissolving a substantially equimolar amount of at least one aromatic dianhydride and at least one diamine in an organic solvent. The solution is prepared by stirring under controlled temperature conditions until polymerization of the acid dianhydride and diamine is complete. These polyamic acid solutions are usually obtained at a concentration of 5 to 35 wt%, preferably 10 to 30 wt%. When the concentration is in this range, an appropriate molecular weight and solution viscosity are obtained.
In addition, polyimide is obtained by imidizing polyamic acid, and chemical curing is used for imidization in the present invention. The chemical curing method comprises a polyamic acid organic solvent solution, a dehydrating agent typified by an acid anhydride such as acetic anhydride, an imidation catalyst typified by a tertiary amine such as isoquinoline, β-picoline, and pyridine. It is a method of acting. A thermal cure method may be used in combination with a chemical cure method. The imidation reaction conditions can vary depending on the type of polyamic acid, the thickness of the film, and the like.
In the method for producing a polyimide film according to the present invention, the polyamic acid organic solvent solution includes a dehydrating agent of 1 molar equivalent or more with respect to amic acid and an imidization catalyst of 0.2 molar equivalent or more with respect to amic acid. Of the polyimide film according to the present invention by casting a resin solution composition to which a curing agent containing a molar ratio of the imidization catalyst of 1: 0.15 to 1: 0.75 is added. A production method is configured, and there is no occurrence of deterioration of mechanical properties, and it is possible to obtain a polyimide film that prevents entrainment of bubbles during casting of a resin film and improves thickness unevenness.
[0013]
Here, the material used for the polyimide precursor polyamic acid composition concerning this invention is demonstrated.
[0014]
Suitable acid anhydrides for use in this polyimide are pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic. Acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone Tetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis (3,4-dicarboxy) Phenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (2,3 -Dicarboxyphenyl) Tan dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride, oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, p-phenylenebis (trimellitic acid mono Ester acid anhydride), ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (trimellitic acid monoester acid anhydride) and the like, and these alone or in a mixture in any proportion Can be preferably used.
Among these, the most suitable acid dianhydride in the polyimide precursor polyamic acid composition used in the present invention is pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenebis (trimellitic acid monoester anhydride), and these may be used alone or in a mixture of any ratio.
[0015]
Suitable diamines that can be used in the polyimide precursor polyamic acid composition according to the present invention are 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane, benzidine, 3,3′-dichlorobenzidine, 4,4. '-Diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1, 5-diaminonaphthalene, 4,4′-diaminodiphenyldiethylsilane, 4,4′-diaminodiphenylsilane, 4,4′-diaminodiphenylethylphosphine oxide, 4,4′-diaminodiphenyl N-methylamine, 4,4 '-Diaminodiphenyl N-phenylamine 1,4-diaminobenzene (p- phenylene diamine), 1,3-diaminobenzene, 1,2-diaminobenzene, and include analogs thereof, singly or in mixture of arbitrary ratio may preferably used.
Among these diamines, 4,4′-diaminodiphenyl ether and p-phenylenediamine are particularly preferable, and a mixture in which these are mixed at a molar ratio of 100: 0 to 0: 100, preferably 100: 0 to 10:90. Can be preferably used.
[0016]
Preferred solvents for synthesizing the polyamic acid are amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N , N-dimethylacetamide can be used particularly preferably.
[0017]
After mixing the polyamic acid varnish obtained by the above method and a curing agent, the polyimide film is continuously extruded as a smooth thin film curtain from a slit die and cast on an endless belt, and is self-supporting by drying and cooling. A gel film having This gel film is further heat-treated to obtain a polyimide film having the desired mechanical properties.
[0018]
Examples of the dehydrating agent to be added to the polyamic acid solution according to the present invention include aliphatic acid anhydrides, aromatic acid anhydrides, N, N′-dialkylcarbodiimides, lower aliphatic halides, halogenated lower aliphatic halides, halogens. Lower fatty acid anhydride, arylphosphonic acid dihalide, thionyl halide, or a mixture of two or more thereof. Of these, aliphatic anhydrides such as acetic anhydride, propionic anhydride, and lactic acid anhydride, or a mixture of two or more thereof can be preferably used. The amount of the dehydrating agent may be 1 to 5 molar equivalents, preferably 1.2 to 4 molar equivalents, more preferably 1.5 to 3 molar equivalents relative to the amic acid. If it is out of this range, the chemical imidation rate falls below the preferred range, or the releasability from the support is deteriorated.
[0019]
Moreover, in order to perform imidation effectively, it is preferable to use an imidation catalyst simultaneously as a dehydrating agent. As the imidization catalyst, an aliphatic tertiary amine, an aromatic tertiary amine, a heterocyclic tertiary amine, or the like is used. Among them, those selected from heterocyclic tertiary amines can be particularly preferably used. Specifically, quinoline, isoquinoline, β-picoline, pyridine and the like are preferably used alone or as a mixture in an arbitrary ratio. The amount of the catalyst may be 0.2 to 1.5 molar equivalents, preferably 0.25 to 1.2 molar equivalents, more preferably 0.3 to 1 molar equivalents relative to the amic acid. If it is out of this range, the chemical imidation rate falls below the preferred range, or the releasability from the support is deteriorated.
[0020]
The amount of the dehydrating agent and the imidization catalyst satisfies the above preferred range, and the molar ratio is 1: 0.15 to 1: 0.75, preferably 1: 0.2 to 1: 0.7. Is preferably used. When the amount of the imidization catalyst is less than 0.15 mol with respect to 1 mol of the dehydrating agent, the chemical imidization does not proceed sufficiently, causing a decrease in strength, and releasing from the support becomes difficult. Or In addition, when the amount of the imidization catalyst exceeds 0.75 mol with respect to 1 mol of the dehydrating agent, the curing rate tends to increase, partial imidization occurs in the resin film, and gel-like defects occur in the film. Or a partially imidized gel-like material is likely to clog the slit die and become a coating streak.
[0021]
The amount of the curing agent added to 100 parts of the polyamic acid solution is preferably 30 to 80 parts, preferably 35 to 75 parts, and more preferably 35 to 70 parts. When the addition amount of the curing agent is less than 30 parts, the viscosity of the resin solution composition to which the curing agent is added becomes high, and phenomena such as entrainment of bubbles and increase in thickness unevenness tend to occur. Further, when the addition amount of the curing agent is more than 80 parts, there are problems such that it takes time to dry and the productivity is lowered, and the amount of the solvent used increases, resulting in an increase in cost.
[0022]
The viscosity of the resin solution composition obtained by adding a curing agent is preferably 600 poise or less, more preferably 400 poise or less as measured by a B-type viscometer at 0 ° C. If the viscosity of the resin solution composition to which the curing agent is added is higher than 600 poise, problems such as an increase in thickness unevenness and an increase in the amount of entrained bubbles tend to occur if high productivity is to be maintained.
[0023]
[0024]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not a thing limited to the content of an Example. In the examples, “parts” represents parts by weight, and “%” represents% by weight.
(Evaluation methods)
1) Measurement of tensile strength The tensile strength was measured according to ASTM D882.
2) Measurement of R value in MD direction The central portion of the obtained polyimide film was sampled 5 m in the MD direction, and continuous thickness measurement was performed using a contact-type continuous thickness meter, and the maximum thickness and the minimum thickness were read from the chart. .
R value = [maximum thickness]-[minimum thickness]
As sought. The unit is μm.
(Comparative Example 1)
(18.5 wt% DMF solution of polyamic acid prepared by synthesizing pyromellitic dianhydride / 4,4′-diaminodiphenyl ether / p-phenylenediamine in a molar ratio of 4/3/1) to 573 g of acetic anhydride and isoquinoline A stainless steel endless belt in which a hardener consisting of 73 g and 154 g of DMF is rapidly stirred with a mixer at a weight ratio of 40% with respect to the polyamic acid DMF solution, extruded from a T die, and travels 25 mm below the die at a speed of 12 m / min. Cast on top. At this time, the viscosity of the resin solution in the T-die was 750 poise at 0 ° C. At this time, the molar ratio of acetic anhydride as a dehydrating agent to 1 mol of amic acid in the polyamic acid varnish was 3.0 times that of acetic anhydride as a dehydrating agent and 0.3 times that of isoquinoline as a catalyst. This resin film was dried and imidized at 130 ° C. × 100 seconds, 300 ° C. × 20 seconds, 450 ° C. × 20 seconds, 500 ° C. × 20 seconds to obtain a 25 μm polyimide film. The properties of this polyimide film are shown in Table 1. Moreover, when this film was investigated, innumerable entrainment of bubbles having a diameter of about 5 mm was observed at both ends of the film.
(Comparative Example 2)
Pyromellitic dianhydride / 4,4′-diaminodiphenyl ether / p-phenylenediamine synthesized in a molar ratio of 4/3/1 to a 18.5 wt% DMF solution of polyamic acid), 764 g of acetic anhydride and isoquinoline A stainless steel endless belt in which a hardener consisting of 97 g and DMF 336 g is rapidly agitated with a mixer at a weight ratio of 60% with respect to the polyamic acid DMF solution, extruded from a T die, and travels 25 mm below the die at a speed of 16 m / min. Cast on top. At this time, the viscosity of the resin solution in the T die was 460 poise at 0 ° C. At this time, the molar ratio of acetic anhydride as a dehydrating agent to 1 mol of amic acid in the polyamic acid varnish was 4.0 times that of acetic anhydride as a dehydrating agent and 0.4 times that of isoquinoline as a catalyst. This resin film was dried and imidized at 140 ° C. × 100 seconds, 300 ° C. × 20 seconds, 450 ° C. × 20 seconds, 500 ° C. × 20 seconds to obtain a 25 μm polyimide film. The properties of this polyimide film are shown in Table 1. Moreover, when this film was investigated, innumerable entrainment of bubbles having a diameter of about 5 mm was observed at both ends of the film.
[0025]
(Comparative Example 3)
A curing agent composed of 632 g of acetic anhydride, 80 g of isoquinoline and 88 g of DMF was added to a 18.5 wt% DMF solution of polyamic acid obtained by synthesizing pyromellitic dianhydride / 4,4′-diaminodiphenyl ether at a molar ratio of 1/1. The mixture was rapidly stirred with a mixer at a weight ratio of 40% with respect to the polyamic acid DMF solution, extruded from a T die, and cast on a stainless steel endless belt running 25 mm below the die at a speed of 12 m / min. At this time, the viscosity of the resin solution in the T-die was 790 poise at 0 ° C. The molar ratio of acetic anhydride as a dehydrating agent to 1 mol of amic acid in the polyamic acid varnish was 3.5 times that of acetic anhydride as a dehydrating agent and 0.35 times that of isoquinoline as a catalyst. This resin film was dried and imidized at 130 ° C. × 100 seconds, 300 ° C. × 20 seconds, 450 ° C. × 20 seconds, 500 ° C. × 20 seconds to obtain a 25 μm polyimide film. The properties of this polyimide film are shown in Table 1. Moreover, when this film was investigated, innumerable entrainment of bubbles having a diameter of about 5 mm was observed at both ends of the film.
[0026]
(Comparative Example 4)
A curing agent composed of 813 g of acetic anhydride, 103 g of isoquinoline and 285 g of DMF was added to a 18.5 wt% DMF solution of polyamic acid obtained by synthesizing pyromellitic dianhydride / 4,4′-diaminodiphenyl ether in a molar ratio of 1/1. The mixture was rapidly stirred with a mixer at a weight ratio of 60% with respect to the polyamic acid DMF solution, extruded from a T die, and cast onto a stainless steel endless belt running 25 mm below the die at a speed of 16 m / min. At this time, the viscosity of the resin solution in the T-die was 480 poise at 0 ° C. At this time, the molar ratio of acetic anhydride as a dehydrating agent to 1 mol of polyamic acid varnish of amic acid was 4.5 times that of acetic anhydride as a dehydrating agent and 0.45 times that of isoquinoline as a catalyst. This resin film was dried and imidized at 140 ° C. × 100 seconds, 300 ° C. × 20 seconds, 450 ° C. × 20 seconds, 500 ° C. × 20 seconds to obtain a 25 μm polyimide film. The properties of this polyimide film are shown in Table 1. Moreover, when this film was investigated, innumerable entrainment of bubbles having a diameter of about 5 mm was observed at both ends of the film.
[0027]
Example 1
(18.5 wt% DMF solution of polyamic acid prepared by synthesizing pyromellitic dianhydride / 4,4′-diaminodiphenyl ether / p-phenylenediamine in a molar ratio of 4/3/1) to 382 g of acetic anhydride and isoquinoline A stainless steel endless belt in which a hardener consisting of 97 g and 318 g of DMF is rapidly stirred with a mixer at a weight ratio of 40% with respect to the polyamic acid DMF solution, extruded from a T die, and travels 25 mm below the die at a speed of 12 m / min. Cast on top. At this time, the viscosity of the resin solution in the T-die was 520 poise at 0 ° C. At this time, the molar ratio of acetic anhydride as a dehydrating agent to 1 mol of amic acid in the polyamic acid varnish was 2.0 times that of acetic anhydride as a dehydrating agent and 0.4 times that of isoquinoline as a catalyst. This resin film was dried and imidized at 130 ° C. × 100 seconds, 300 ° C. × 20 seconds, 450 ° C. × 20 seconds, 500 ° C. × 20 seconds to obtain a 25 μm polyimide film. The properties of this polyimide film are shown in Table 1.
[0028]
(Example 2)
(18.5 wt% DMF solution of polyamic acid prepared by synthesizing pyromellitic dianhydride / 4,4′-diaminodiphenyl ether / p-phenylenediamine in a molar ratio of 4/3/1) to 382 g of acetic anhydride and isoquinoline A stainless steel endless belt in which a curing agent composed of 169 g and DMF 249 g is rapidly stirred with a mixer at a weight ratio of 60% with respect to the polyamic acid DMF solution, extruded from a T die, and travels 25 mm below the die at a speed of 16 m / min. Cast on top. At this time, the viscosity of the resin solution in the T-die was 320 poise at 0 ° C. The molar ratio of acetic anhydride as a dehydrating agent to 1 mol of polyamic acid varnish of amic acid was 2.0 times that of acetic anhydride as a dehydrating agent and 0.7 times that of isoquinoline as a catalyst. This resin film was dried and imidized at 140 ° C. × 100 seconds, 300 ° C. × 20 seconds, 450 ° C. × 20 seconds, 500 ° C. × 20 seconds to obtain a 25 μm polyimide film. The properties of this polyimide film are shown in Table 1.
[0029]
(Example 3)
A curing agent composed of 361 g of acetic anhydride, 103 g of isoquinoline and 336 g of DMF was added to a 18.5 wt% DMF solution of polyamic acid obtained by synthesizing pyromellitic dianhydride / 4,4′-diaminodiphenyl ether at a molar ratio of 1/1. The mixture was rapidly stirred with a mixer at a weight ratio of 40% with respect to the polyamic acid DMF solution, extruded from a T die, and cast on a stainless steel endless belt running 25 mm below the die at a speed of 12 m / min. At this time, the viscosity of the resin solution in the T-die was 580 poise at 0 ° C. At this time, the molar ratio of acetic anhydride as a dehydrating agent to 1 mol of amic acid in the polyamic acid varnish was 2.0 times that of acetic anhydride as a dehydrating agent and 0.45 times that of isoquinoline as a catalyst. This resin film was dried and imidized at 130 ° C. × 100 seconds, 300 ° C. × 20 seconds, 450 ° C. × 20 seconds, 500 ° C. × 20 seconds to obtain a 25 μm polyimide film. Table 1 shows the characteristics of the polyimide film.
Example 4
A curing agent composed of 271 g of acetic anhydride, 228 g of isoquinoline and 301 g of DMF was added to a 18.5 wt% DMF solution of polyamic acid obtained by synthesizing pyromellitic dianhydride / 4,4′-diaminodiphenyl ether in a molar ratio of 1/1. The mixture was rapidly stirred with a mixer at a weight ratio of 60% with respect to the polyamic acid DMF solution, extruded from a T die, and cast onto a stainless steel endless belt running 25 mm below the die at a speed of 16 m / min. At this time, the viscosity of the resin solution in the T-die was 360 poise at 0 ° C. At this time, the molar ratio of acetic anhydride as a dehydrating agent to 1 mol of amic acid in the polyamic acid varnish was 1.5 times that of acetic anhydride as a dehydrating agent and 1.0 times that of isoquinoline as a catalyst. This resin film was dried and imidized at 140 ° C. × 100 seconds, 300 ° C. × 20 seconds, 450 ° C. × 20 seconds, 500 ° C. × 20 seconds to obtain a 25 μm polyimide film. Table 1 shows the characteristics of the polyimide film.
[0030]
[Table 1]

[0031]
【The invention's effect】
As described above, the present invention reduces the viscosity of the solution in the extrusion die by adjusting the curing agent composition, thereby preventing entrainment of bubbles in high-speed film formation and preventing occurrence of thickness unevenness in the MD direction. On the other hand, the manufacturing method of the polyimide film excellent in the mechanical characteristic can be provided.
[Brief description of the drawings]
[Fig. 1] Polyimide film manufacturing process [Fig. 2] Curtain extruded from die lip by casting method [Description of symbols]
2; Extruder 4; Slit dies 6 and 20; Die lips 8 and 26; Resin films 10 and 24; Conveyor belt 22;

Claims (4)

In the method for producing a polyimide film by casting a composition containing a polyamic acid to form a polyimide film,
In an organic solvent solution of polyamic acid, 1 to 5 molar equivalents of a dehydrating agent with respect to amic acid and 0.2 to 1.5 molar equivalents of an imidizing catalyst with respect to amic acid are added in a molar ratio of the dehydrating agent to the imidization catalyst. Including a step of adding a curing agent containing a ratio of 1: 0.15 to 1: 0.75 ,
A method for producing a polyimide film, comprising adding 30 to 80 parts of a curing agent to 100 parts of an organic solvent solution of polyamic acid . The method for producing a polyimide film according to claim 1, wherein the resin solution composition obtained by adding a curing agent to an organic solvent solution of polyamic acid has a viscosity at 0 ° C of 600 poise or less . The method for producing a polyimide film according to claim 1 or 2, wherein the viscosity at 0 ° C of a resin solution composition obtained by adding a curing agent to an organic solvent solution of polyamic acid is 400 poise or less . The method for producing a polyimide film according to any one of claims 1 to 3, wherein the imidization catalyst is a tertiary amine .

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