JP2006117791A - Method for producing polyimide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyimide film having high flatness and being free of appearance defects such as wrinkles, cracks, and tears by means of a simple apparatus. <P>SOLUTION: What is provided is a method for producing a polyimide film comprising directly applying an organic solvent solution of a polyamic acid as a precursor of a polyimide to a support having a polyimide layer (B) on a metallic foil, heat-treating this together with the support at 200°C or higher to imidize the polyamic acid, releasing the imidized polyimide film (A) by peeling it from the support, wherein the polyimide layer situated at the face where the polyimide layer (B) comes into contact with the polyimide film (A) is a polyimide resin layer obtained from a tetracarboxylic acid compound containing 30 to 100 mol% pyromellitic dianhydride and a diamine. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a polyimide film, and in particular, a method for producing a polyimide film capable of obtaining a polyimide film having a high flatness using a simple apparatus and free from defects in appearance such as wrinkles, cracks and tears. It is about.

  Polyimide films are known to have excellent properties such as heat resistance, chemical resistance, electrical insulation, and mechanical properties, and are widely used for electrical insulation films, heat insulation films, base films for flexible wiring boards, etc. Has been. In particular, in the use of a flexible wiring board, it is used as a support for an electric wiring board in which a metal foil or a metal thin film represented by a copper foil is laminated. Moreover, since the flexible wiring board which uses a polyimide film as a support body can be bent, it has been frequently used for small electronic devices, and has come to occupy an important position as a flexible wiring board. In recent years, with the diversification of applications of electrical wiring boards and the progress of higher density of wiring, the mechanical properties as the base film of flexible wiring boards and the improvement of its in-plane isotropy and dimensional stability are further demanded. It came to be able to.

  By the way, in general, a polyimide film is obtained by applying an organic solvent solution of polyamic acid, which is a polyimide precursor, onto a support, evaporating the solvent until it becomes a self-supporting film, The support polyamic acid film is peeled off, and further heated while gripping both ends of the film to complete the removal of the remaining solvent and the imidization of the polyamic acid. However, in the conventionally known method, when heating the self-supporting film peeled from the support, wrinkles due to shrinkage of the film, cracks due to film rigidity, tearing, and the like may occur. In addition, removal of the remaining solvent by heating while holding both ends of the film and completion of imidation of the polyamic acid are carried out in an equipment having a continuous holding mechanism with a clip or pin type tenter, but the heat treatment temperature is 300. Since the temperature is higher than 400 ° C., preferably higher than 400 ° C., very expensive equipment is required. Furthermore, since the solvent acts as a plasticizer in the self-supporting film, the film is easily stretched by heat treatment under tension. Therefore, in order to obtain in-plane isotropic properties, when the film isolated from the support is subjected to heat treatment, the in-plane orientation is usually adjusted by controlling the stretching ratio.

In Patent Document 1, there is a method in which a self-supporting film stretched in at least one direction is dried until the amount of the solvent remaining in the film is 10% or less with respect to the polymer weight, whereby heat treatment is performed without restraint. Although described, the self-supporting film is peeled off from the support and is dried under restraint, so that equipment with both-end gripping mechanisms for drying is still required. Further, Patent Document 2 reports a method in which a polyamic acid solution is cast-coated on a dissolvable support and completely cured, and then the support is dissolved and removed. In addition to the need for a process, mixing of impurities into the film due to chemical treatment is unavoidable, and there is a concern about deterioration in film characteristics. Further, in Patent Document 3, it is reported that a metal coated with a release agent such as a silicon resin, a fluororesin or an ammonium ammonium phosphate is used as a support.
JP 2003-268132 A JP-A-7-76024 JP-A-61-55177

  However, the release agent used in Patent Document 3 does not have a heat resistance of 300 ° C. or higher necessary for completing imidization of the polyamic acid, and is therefore heated to the temperature at which the imidation of the polyamic acid is completed together with the support. In such a case, the surface of the film is roughened due to the fusion of the release agent to the film or the flow of the release agent, and it is difficult to obtain a film that is favorable in appearance.

  The present invention does not require a both-end gripping device and a technique for adjusting the in-plane orientation degree by controlling the stretching ratio in the production of a polyimide film, and has a higher flatness and a higher appearance such as wrinkles, cracks and tears by a simpler device. An object is to obtain a polyimide film free from defects.

  As a result of repeated studies in view of the above problems, polyamic acid is applied on a support having a polyimide layer having a specific composition on the surface, and after heat treatment, polyamic acid is imidized and then peeled off from the support. The inventors have found that the above-mentioned problems can be solved by isolating the polyimide film, and have reached the present invention.

  That is, the present invention directly applies an organic solvent solution of polyamic acid, which is a precursor of polyimide, on a support having a polyimide layer (B) on a metal foil, and heat-treats this with the support to 200 ° C. or more. After the imidization of the polyamic acid, the polyimide film (A) is peeled off from the support to isolate the polyimide film (A) and the polyimide film (A) with the polyimide film (A) The polyimide layer located on the contact surface is a polyimide resin obtained from a tetracarboxylic acid compound containing 30 to 100 mol% of pyromellitic dianhydride and a diamine.

Hereinafter, the present invention will be described in more detail.
The support used in the present invention is composed of a metal foil having a polyimide layer (B) on the surface. The polyimide layer may be a single layer or a plurality of layers. For metal foil, copper, aluminum, stainless steel, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, zirconium, gold, cobalt, titanium, tantalum, zinc, lead, tin, silicon, bismuth, indium or alloys thereof Examples thereof include metals selected from such as those that are stable to high-temperature treatment.

  For these metal foils, sizing, chrome plating, nickel plating, chromium-nickel plating, copper-zinc alloy plating, copper oxide precipitation, or aluminum alcoholate on the surface for the purpose of improving the adhesive strength with the polyimide layer (B), etc. , Chemical or surface roughening treatment with aluminum chelates, silane coupling agents, triazine thiols, benzotriazoles, acetylene alcohols, acetylacetones, catechols, o-benzoquinones, tannins, quinololols, etc. Surface treatment may be performed.

  Moreover, in order to prevent wrinkles or warpage from occurring due to stress generated during heat treatment, a thick metal foil is preferred, but from the viewpoint of ease of handling, 10 to 100 μm is preferred. In order to prevent the influence of the stress, the thickness of the polyimide layer (B) is preferably about 1/10 to 1/2 of the metal foil, that is, preferably 1 to 50 μm, more preferably 10 to 40 μm. . Although there is no restriction | limiting in the thickness of the polyimide film (A) obtained, The range of 5-50 micrometers, Preferably 10-40 micrometers is suitable.

  The polyimide layer (B) has pyromellitic dianhydride as its surface layer (if it consists of a single layer, its own layer, if it consists of multiple layers, the outer layer on the side opposite to the layer in contact with the metal foil) It is necessary to form a polyimide layer (C) composed of a polyimide resin obtained by reacting a tetracarboxylic acid compound containing (PMDA) of 30 mol% or more, preferably 40 mol% or more with a diamino compound. In the present invention, if the surface layer of the polyimide layer (B) is a polyimide layer (C), there is an advantage that peeling can be easily performed even if the type of the polyimide film (A) changes. Here, if the content of pyromellitic dianhydride (PMDA) in the tetracarboxylic acid compound used is less than 30 mol%, the polyimide film (A) formed on the support cannot be easily peeled off. In addition, a strong force is required for peeling, or peeling itself becomes difficult.

  In the present invention, the polyimide film (A) and the polyimide layer (B) can be composed of a single layer or a plurality of layers. Polyimide resin constituting the polyimide film (A) and the polyimide layer (B) is a polyimide layer (C) of the polyimide layer (B), that is, pyromellitic dianhydride on the contact surface with the polyimide film (A). The polyimide layer (B) preferably has a heat resistance of 300 ° C. or higher, although there is no particular limitation except that the content of (PMDA) is not less than a certain amount. When the polyimide layer (B) is composed only of the polyimide layer (C), the polyimide layer (B) is also the polyimide layer (C). Surprisingly, even if the type of the polyimide film (A), that is, the polyamic acid to be imidized, changes, the appropriate polyimide layer (B) satisfies the above conditions.

  The polyimide resin referred to in the present invention is a polyimide resin formed by polycondensation of tetracarboxylic dianhydride and diamine, an imide portion formed by polycondensation of tetracarboxylic dianhydride and diamine, and an amic acid portion. Typical examples thereof include a polyamic acid resin having a polyamic acid resin and a polyamic acid resin obtained by polycondensation of tetracarboxylic dianhydride and diamine, but any resin having an imide bond in a repeating unit after curing may be used. However, the polyimide constituting the polyimide layer (C) has a predetermined amount of units derived from PMDA.

  The polyimide resin or precursor thereof used in the present invention (refers to the polyimide resin of the polyimide layer (B) and the polyamic acid to be the polyimide film (A) resin, these are collectively referred to as polyimide resin)) is a known method Can be manufactured. For example, polyamic acid, which is a precursor of polyimide resin, is synthesized in a solution using approximately equimolar amounts of tetracarboxylic dianhydride and diamine as raw materials. The polyimide is produced in two stages in which polyimide is produced by an imidization reaction.

  Examples of raw diamino compounds include 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,6-dimethyl-m-phenylenediamine 2,5-dimethyl-p-phenylenediamine, 2,4-diaminomesitylene, 4,4'-methylenedi-o-toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4'-methylene- 2,6-diethylaniline, 2,4-toluenediamine, m-phenylene-diamine, p-phenylene-diamine, 4,4'-diamino-diphenylpropane, 3,3'-diamino-diphenylpropane, 4,4 ' -Diamino-diphenylethane, 3,3'-diamino-diphenylethane, 4,4'-diamino-diphenylmethane, 3,3'-diamino-diphenylmethane, 2,2-bis [4- (4-aminophenoxy) phenyl] Propane, 4,4'-diamino-diphenyl sulfide, 3,3'-diamino-diphenyl sulfide, 4,4'-diamino-diphenyl Sulfone, 3,3'-diamino-diphenylsulfone, 4,4'-diamino-diphenyl ether, 3,3'-diamino-diphenyl ether, benzidine, 3,3'-diamino-biphenyl, 3,3'-dimethyl-4, 4'-diamino-biphenyl, 3,3'-dimethoxy-benzidine, 4,4'-diamino-p-terphenyl, 3,3'-diamino-p-terphenyl, bis (p-amino-cyclohexyl) methane, Bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-amino-pentyl) benzene, p-bis ( 1,1-dimethyl-5-amino-pentyl) benzene, 1,5-diamino-naphthalene, 2,6-diamino-naphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4- Diamino-toluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylene-diamine, p-xylylene-diamine, 2,6-diamino-pi Lysine, 2,5-diamino-pyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-amino) And phenoxy) benzene. These diamino compounds can use 1 type, or 2 or more types.

  The tetracarboxylic acid compound is not particularly limited except that the polyimide constituting the polyimide layer (C) requires PMDA. With respect to the polyimide constituting the polyimide layer (C), 40 mol% or more of PMDA is required, and other tetracarboxylic acid compounds as described below can be used. The tetracarboxylic acid compound only needs to react with diamine to form a polyimide, and is not limited to dianhydrides, but is often used in dianhydrides. explain. Therefore, PMDA is understood to represent a pyromellitic acid compound.

  PMDA can also be used for polyimide layers other than the polyimide constituting the polyimide layer (C) or polyamic acid, but other examples of tetracarboxylic acid compounds include 3,3 ′, 4,4 ′. -Biphenyltetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 2,2', 3,3'-benzophenone tetra Carboxylic dianhydride, 2,3,3 ', 4'-benzophenone tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,5,6 -Tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride, naphthalene-1,2,6, 7-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6-tetracarboxylic dianhydride, 4,8- Dimethyl-1,2,3,5,6,7 -Hexahydronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1 , 4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 1,4,5,8-tetra Chloronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 3,3 ', 4,4'-diphenyltetracarboxylic dianhydride, 2,2', 3,3'-diphenyltetracarboxylic acid Dianhydride, 2,3,3 ', 4'-diphenyltetracarboxylic dianhydride, 3,3``, 4,4' '-p-terphenyltetracarboxylic dianhydride, 2,2' ' , 3,3``-p-terphenyltetracarboxylic dianhydride, 2,3,3 '', 4 ''-p-terphenyltetracarboxylic dianhydride, 2,2-bis (2,3 -Dicarboxyphenyl) -propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3-dicarboxy Phenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3.4-dicarboxyphenyl) methane dianhydride, Bis (2,3-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1 , 1-bis (3,4-dicarboxyphenyl) ethane dianhydride, perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride Perylene-4,5,10,11-tetracarboxylic dianhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride Anhydride, phenanthrene-1,2,6,7-tetracarboxylic dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3, 4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4 , 5-tetracarboxylic dianhydride and the like.

  A known method can be used to synthesize these polyimide resins. For example, in a solvent, a diamino compound and a carboxylic dianhydride are mixed at an approximately equimolar ratio and reacted in a reaction temperature range of 0 to 200 ° C., preferably in a range of 0 to 100 ° C. There is a method for obtaining a polyimide resin by obtaining a precursor and further imidizing it.

  The organic solvent used in the production of the polyimide resin precursor is not particularly limited, but may be a mixed solvent of one type or two or more types as long as the resin component can be uniformly dissolved. Absent. For example, phenol solvents, amide solvents (pyrrolidone solvents, acetamide solvents, etc.), oxane solvents (dioxane, trioxane, etc.), ketone solvents (cyclohexanone, etc.), glyme solvents (methyl diglyme, methyl triglyme, etc.) )and so on. If necessary, aromatic hydrocarbon solvents such as benzene and toluene and aliphatic hydrocarbon solvents such as hexane and decane can be appropriately mixed and used.

  The support used in the present invention can also be produced by applying a polyimide or precursor resin solution onto a metal foil, drying, and heat-treating. The polyimide precursor resin solution is imidized to obtain a polyimide resin solution. Then, it can also apply | coat, dry, and heat-process on metal foil. A polyimide resin layer formed by applying a polyimide precursor resin solution or a polyimide resin solution onto a metal foil is dried. In the case of a precursor resin layer, this is further 200 ° C. or higher, preferably 300 ° C. or higher. It heat-processes and imidation reaction is performed. When the resin layer is provided in multiple layers, repeat the operation of applying a plurality of resin solutions on the metal foil and drying, or by applying multiple layers simultaneously with a multi-layer die and drying, as in the case of single layer formation. Thus, a polyimide resin layer having a multilayer structure can be formed on the metal foil. In addition, when providing in a multilayer, it is good to imidize collectively what was apply | coated and dried in multiple layers.

  The method for producing a polyimide film of the present invention includes (1) a step of applying an organic solvent solution of polyamic acid, which is a precursor resin of polyimide, onto a support (application step), and (2) a solvent by heating the whole support. And (3) a step of peeling the polyimide film from the support (peeling step), and in principle performed in this order.

  When making a polyimide film (A) with a multilayer structure, repeat the operation of applying a plurality of polyamic acid solution resin solutions on the support and drying them, or simultaneously applying and drying with a multilayer die or the like, and finally By imidizing, a multi-layered polyimide resin layer can be formed on the support in the same manner as the single layer formation.

  The polyimide resin layer formed by applying the polyimide precursor resin solution onto the support is dried together with the support, and further subjected to an imidization reaction by heating at 200 ° C. or higher, preferably 300 ° C. or higher. Do.

  After the heating / heat treatment step, the polyimide film (A) is obtained by peeling from the interface with the polyimide layer (B) of the support. Although there is no limitation in particular in the peeling method, when using a roll-shaped support body, it can peel from a support body, winding a polyimide film in roll shape.

  The present invention does not require a both-end gripping device and a technique for adjusting the degree of in-plane orientation by controlling the stretching ratio in the production of a polyimide film, and has a higher level of flatness and more appearance such as wrinkles, cracks, and tears by a simpler device. It is possible to obtain a polyimide film having no defects.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, of course, this invention is not limited to this.
In addition, the symbol used for the present Example shows the following compounds.
1,3-BAB: 1,3-bis (4-aminophenoxy) benzene
BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane
DADMB: 4,4'-diamino-2,2'-dimethylbiphenyl
DPE: 4,4'-diamino-diphenyl ether
PMDA: pyromellitic dianhydride
BPDA: 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride
BTDA: 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride
DSDA: Diphenylsulfone tetracarboxylic dianhydride
DMAc: N, N-dimethylacetamide

Synthesis example 1
In 255 g of DMAc, 19.11 g (0.090 mol) of DADMB and 2.92 g of 1,3-BAB (0.010 mol) were dissolved in a vessel with stirring. Next, 5.79 g BPDA (0.020 mol) and 17.17 g PMDA (0.079 mol) were added. Thereafter, stirring was continued for about 3 hours to carry out a polymerization reaction to obtain a polyamic acid resin solution a having a solid concentration of 15% by weight and a solution viscosity of 200 poise.

Synthesis example 2
In 255 g of DMAc, 11.32 g (0.053 mol) of DADMB and 10.68 g of DPE (0.053 mol) were dissolved in a vessel with stirring. Next, 22.99 g PMDA (0.105 mol) was added. Thereafter, stirring was continued for about 3 hours to carry out a polymerization reaction to obtain a polyamic acid resin solution b having a solid concentration of 15% by weight and a solution viscosity of 350 poise.

Synthesis example 3
In 255 g DMAc, 28.9 g BAPP (0.070 mol) was dissolved in a container with stirring. Then 1.07 g BPDA (0.004 mol) and 15.03 g PMDA (0.069 mol) were added. Thereafter, stirring was continued for about 3 hours to carry out a polymerization reaction to obtain a polyamic acid resin solution c having a solid concentration of 15% by weight and a solution viscosity of 50 poise.

Synthesis example 4
In 255 g DMAc, 17.37 g DAPE (0.088 mol) was dissolved in a container with stirring. Then 27.62 g of BTDA (0.086 mol) was added. Thereafter, stirring was continued for about 3 hours to effect curing to obtain a polyamic acid resin solution d having a solid content concentration of 15% by weight and a solution concentration of 100 poise.

Synthesis example 5
In 255 g of DMAc, 22.25 g of 1,3-BAB (0.076 mol) was dissolved in a container with stirring. Next, 16.18 g DSDA (0.045 mol) and 6.57 g PMDA (0.030 mol) were added. Thereafter, stirring was continued for about 3 hours to carry out a polymerization reaction to obtain a polyamic acid resin solution e having a solid concentration of 15% by weight and a solution viscosity of 80 poise.

Example 1
On the 18 μm thick copper foil (BHY-22B-T, manufactured by Nikko Materials Co., Ltd., hereinafter referred to as the copper foil), the polyamic acid resin solution a obtained in Synthesis Example 1 is 180 μm. After uniformly coating with a thickness, it was dried by heating at 130 ° C. to remove the solvent. Next, heat treatment was performed from 160 ° C. to 360 ° C. at a temperature increase rate of about 15 ° C./min to imidize, thereby obtaining a support 1 having a polyimide resin layer having a thickness of 25 μm formed on a copper foil.
On the polyimide resin layer of the obtained support 1, the polyamic acid resin solution a obtained in Synthesis Example 1 was uniformly applied with a thickness of 180 μm and then dried by heating at 130 ° C. to remove the solvent. Next, heat treatment was performed from 160 ° C. to 360 ° C. at a rate of temperature increase of about 15 ° C./min to imidize, and after cooling to room temperature, the film was peeled off from the support to obtain a polyimide film having a thickness of 25 μm. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 2
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 1 except that the polyamic acid resin solution e obtained in Synthesis Example 5 was used for the polyamic acid resin solution applied on the support. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 3
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 1 except that the polyamic acid resin solution d obtained in Synthesis Example 4 was used for the polyamic acid resin solution applied on the support. In the obtained film, no defects in appearance such as wrinkles, cracks, tears and contamination of the film peeling surface were observed.

Example 4
The polyamic acid resin solution e obtained in Synthesis Example 5 was uniformly applied to a thickness of 180 μm on a copper foil having a thickness of 18 μm, and then dried by heating at 130 ° C. to remove the solvent. Next, heat treatment was performed from 160 ° C. to 360 ° C. at a rate of temperature increase of about 15 ° C./min to imidize to obtain a support 2 having a polyimide resin layer having a thickness of 25 μm formed on a copper foil.
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 1 except that the obtained support 2 was used as the support. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 5
The polyamic acid resin solution c obtained in Synthesis Example 3 was uniformly applied to a thickness of 15 μm on a copper foil having a thickness of 18 μm, and then heated and dried at 130 ° C. to remove the solvent. Next, the polyamic acid resin solution a obtained in Synthesis Example 1 was uniformly applied with a thickness of 130 μm and then dried by heating at 130 ° C. to remove the solvent. Furthermore, after the polyamic acid resin solution c obtained in Synthesis Example 3 was uniformly applied with a thickness of 30 μm, it was dried by heating at 130 ° C. to remove the solvent. Thereafter, heat treatment was performed from 160 ° C. to 360 ° C. at a rate of temperature increase of about 15 ° C./min to imidize to obtain a support 3 having a three-layer polyimide resin layer having a thickness of 25 μm formed on a copper foil.
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 1 except that the obtained support 3 was used as the support. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 6
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 5 except that the polyamic acid resin solution b obtained in Synthesis Example 2 was used as the polyamic acid resin solution to be coated on the support. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 7
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 5 except that the polyamic acid resin solution c obtained in Synthesis Example 3 was used as the polyamic acid resin solution to be coated on the support. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 8
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 5 except that the polyamic acid resin solution d obtained in Synthesis Example 4 was used as the polyamic acid resin solution to be coated on the support. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 9
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 5 except that the polyamic acid resin solution e obtained in Synthesis Example 5 was used as the polyamic acid resin solution to be coated on the support. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 10
The support 3 in which three polyimide resin layers were formed on a copper foil having a thickness of 18 μm was used in the same manner as in Example 5. The polyamic acid resin solution c obtained in Synthesis Example 3 was uniformly applied to a thickness of 15 μm on the polyimide resin layer of the support 3 and then dried by heating at 130 ° C. to remove the solvent. Next, the polyamic acid resin solution a obtained in Synthesis Example 1 was uniformly applied with a thickness of 130 μm and then dried by heating at 130 ° C. to remove the solvent. Furthermore, after the polyamic acid resin solution c obtained in Synthesis Example 3 was uniformly applied with a thickness of 30 μm, it was dried by heating at 130 ° C. to remove the solvent. Thereafter, it was heat-treated from 160 ° C. to 360 ° C. at a rate of temperature increase of about 15 ° C./min, imidized, then cooled to room temperature, and then peeled off from the support to obtain a three-layer polyimide film having a thickness of 25 μm. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Example 11
The polyamic acid resin solution c obtained in Synthesis Example 3 was uniformly applied to a thickness of 15 μm on a copper foil having a thickness of 18 μm, and then heated and dried at 130 ° C. to remove the solvent. Next, the polyamic acid resin solution a obtained in Synthesis Example 1 was uniformly applied with a thickness of 130 μm and then dried by heating at 130 ° C. to remove the solvent. Furthermore, after the polyamic acid resin solution e obtained in Synthesis Example 5 was uniformly applied with a thickness of 30 μm, it was dried by heating at 130 ° C. to remove the solvent. Thereafter, heat treatment was carried out from 160 ° C. to 360 ° C. at a rate of temperature increase of about 15 ° C./min to imidize, thereby obtaining a support 4 having a three-layer polyimide resin layer having a thickness of 25 μm formed on a copper foil.
A polyimide film having a thickness of 25 μm was obtained in the same manner as in Example 1 except that the obtained support 4 was used as the support. The obtained film did not show defects in appearance such as wrinkles, cracks and tears, and contamination of the film peeling surface.

Comparative Example 1
The polyamic acid resin solution d obtained in Synthesis Example 4 was uniformly applied with a thickness of 180 μm on a copper foil having a thickness of 18 μm, and then dried by heating at 130 ° C. to remove the solvent. Next, heat treatment was performed from 160 ° C. to 360 ° C. at a rate of temperature increase of about 15 ° C./min to imidize, thereby obtaining a support 5 having a polyimide resin layer having a thickness of 25 μm formed on a copper foil.
As the support, except that the obtained support 5 was used, coating and heat treatment were performed in the same manner as in Example 1, but the adhesive force between the polyimide film and the support interface was strong, and the polyimide film was removed from the support. It could not be peeled off.

Comparative Example 2
The coating and heat treatment were performed in the same manner as in Example 2 except that the support 5 was used as the support, but the adhesion between the polyimide film and the support was strong, and the polyimide film was peeled off from the support. I could not.

Comparative Example 3
The coating and heat treatment were performed in the same manner as in Example 3 except that the support 5 was used as the support, but the adhesive strength between the polyimide film and the support was strong, and the polyimide film was peeled off from the support. I could not.

Comparative Example 4
The polyamic acid resin solution c obtained in Synthesis Example 3 was uniformly applied to a thickness of 15 μm on a copper foil having a thickness of 18 μm, and then heated and dried at 130 ° C. to remove the solvent. Next, the polyamic acid resin solution a obtained in Synthesis Example 1 was uniformly applied with a thickness of 130 μm and then dried by heating at 130 ° C. to remove the solvent. Further, the polyamic acid resin solution d obtained in Synthesis Example 4 was uniformly applied with a thickness of 30 μm, and then dried by heating at 130 ° C. to remove the solvent. Thereafter, the substrate 6 was heat-treated from 160 ° C. to 360 ° C. at a rate of temperature increase of about 15 ° C./min to be imidized to obtain a support 6 on which a three-layer polyimide resin layer having a thickness of 25 μm was formed on a copper foil.
As the support, except that the obtained support 6 was used, coating and heat treatment were performed in the same manner as in Example 1, but the adhesive force between the polyimide film and the support interface was strong, and the polyimide film was removed from the support. It could not be peeled off.

Comparative Example 5
Application and heat treatment were performed in the same manner as in Example 6 except that the support 6 was used as the support, but the adhesive strength between the polyimide film and the support was strong, and the polyimide film was peeled off from the support. I could not.

Comparative Example 6
As the support, except that the support 6 was used, application and heat treatment were performed in the same manner as in Example 7, but the adhesive force between the polyimide film and the support was strong, and the polyimide film was peeled off from the support. I could not.

Comparative Example 7
As the support, except that the support 6 was used, coating and heat treatment were performed in the same manner as in Example 8, but the adhesive force between the polyimide film and the support was strong, and the polyimide film was peeled off from the support. I could not.

Comparative Example 8
The coating and heat treatment were performed in the same manner as in Example 10 except that the support 6 was used as the support, but the adhesive force between the polyimide film and the support was strong, and the polyimide film was peeled off from the support. I could not.

Comparative Example 9
Except for using a copper foil having no polyimide layer as a support, coating and heat treatment were carried out in the same manner as in Example 1, but the adhesion between the polyimide film and the support was strong, and the polyimide film was removed from the support. It could not be peeled off.

Comparative Example 10
A 25 μm thick polyimide film was used in the same manner as in Example 1 except that a 50 μm thick aluminum foil coated with a silicone release agent (manufactured by Toray Dow Corning Silicone Co., Ltd .: SD7229) was used as the support. Obtained. The obtained film had spontaneous peeling and partial fusion from the support during the heat treatment, and thus had wrinkles, and transfer of the release agent was observed on the film peeling surface.

Claims (3)

  A polyamic acid organic solvent solution, which is a polyimide precursor, is directly applied onto a support having a polyimide layer (B) on a metal foil, and the polyamic acid is heat-treated at 200 ° C. or more together with the support. After the imidization, the polyimide film (A) that has been imidized from the support is peeled off and isolated, and the polyimide layer (B) is contacted with the polyimide film (A). A method for producing a polyimide film, wherein the polyimide layer located in is a polyimide resin obtained from a tetracarboxylic acid compound containing 30 to 100 mol% of pyromellitic dianhydride and a diamine.   The manufacturing method of the polyimide film whose metal foil of a support body is 10-100 micrometers in thickness, and whose polyimide layer (B) is 1-50 micrometers in thickness. The method for producing a polyimide film according to claim 1 or 2, wherein the polyimide film (A) or the polyimide layer (B) comprises a single layer or a plurality of polyimide layers.