JP2019206705A - Method for producing polyimide-based film - Google Patents

Abstract

To provide a method for efficiently producing a thinner polyimide-based film having excellent heat resistance, surface smoothness, optical characteristics and transparency with a high yield.SOLUTION: There is provided a method for producing a polyimide-based film having a surface roughness (Rz) of less than 0.08 μm which comprises the following steps (A) to (C). Step (A): obtaining a metal laminate A by laminating a polyamide-imide resin A1 polymerized from a specific acid component and a diamine component on a part or the whole of a surface of a metal material having a mirror glossiness of 200 or more, a surface roughness (Rz) of 0.5 μm or less and a Young's modulus of 50 kN/mmor more, and crosslinking the resin A1 with an epoxy resin, step (B): obtaining a metal laminate B by further laminating a polyimide-based resin B different from the polyamide-imide resin A1 on the surface of a polyamide-imide resin A1 layer of the metal laminate A and step (C): obtaining a polyimide-based film by peeling a polyimide-based resin B layer from the metal laminate B.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a polyimide film. More specifically, heat resistance, transparency, surface smoothness used for various members such as optical members, electrical / electronic members, opto-device members, mechanical members, etc. that require heat resistance, such as electronic information equipment and automotive applications. The present invention relates to a method for producing a polyimide film having excellent properties, optical characteristics, and film forming processability.

  In general, a polyimide resin is widely used as an insulating material for electric and electronic devices because it is excellent in heat resistance, insulation, chemical resistance, and the like, and is excellent in workability.

Usually, as a manufacturing method of a polyimide film, the dry-type film forming method which consists of the following processes (1)-(3) is typical.
(1) A polyamic acid solution is applied on a support such as an endless belt or a drum and dried.
(2) The self-supporting film is peeled off before adhering to the support.
(3) Further heat treatment and imidization.
For example, it is formed by peeling the film from the support while leaving a certain solvent in steps (2) to (3), and heat-treating again while holding both ends of the film by a pin tenter method or the like (Patent Document) 1, 2, 3).

  However, normally, a support such as an endless belt or a drum is made of a hard material such as a metal material, and thus does not necessarily have a smooth surface property. In addition, scratches, dents, and the like are likely to enter. For this reason, there is a problem that it is difficult to obtain a polyimide-based film satisfying the surface smoothness by the conventional method of coating on the support and peeling and manufacturing.

  In addition, in the conventional method in which a polyimide resin solution is applied onto a support such as an endless belt or a drum, the coating film is dried, and then the film is peeled off from the support, if the applied film is thin, the peelability may be reduced. Deteriorate. In addition, there is a problem that wrinkles and scratches are easily formed on the film, and the film forming processability is poor.

  In addition, a method has been proposed in which a base material having a polyimide resin surface is used as a support, and a polyamic acid solution is applied to the surface, dried, imidized, and the polyimide film is peeled off from the support base material. , Hydrolysis occurs in the imidization step. This hydrolysis causes partial cleavage of the imide ring on the release surface in contact with the polyamic acid layer, increasing the wettability of the release surface on the support side (lowering the contact angle), and worsening the release property. was there. As a result, when two or more cycles are performed, it is necessary to perform heat treatment again to recover the surface state, so that the production efficiency is not good. In addition, since it is necessary to treat the film at a high temperature in the imidization process, the film is likely to be colored, and it has been difficult to obtain a film that satisfies transparency, surface smoothness, and optical properties (patent) References 4, 5, 6).

  As a method for solving the above problem, a metal laminate in which a specific polyamideimide resin is laminated on the surface of a metal material is used as a support, and another polyamideimide resin is laminated to form a film, and then the film is peeled off. Has reported a method for producing a polyamideimide film excellent in heat resistance, transparency, surface smoothness and optical properties (Patent Document 7).

JP 09-29852 A Japanese Patent No. 4428016 Japanese Patent No. 425391 JP 2004-322441 A Japanese Patent No. 5234642 JP 2010-201890 A JP 2012-229402 A

Although the said method is an outstanding manufacturing method of a polyamideimide film, it is not described in particular about the film forming workability including the characteristic of the metal material which comprises a support body.
As described above, the prior art has the following problems.
(1) A polyimide film that satisfies transparency, surface smoothness, and optical properties is difficult to manufacture.
(2) It is difficult to manufacture a thin polyimide film.
(3) In a film forming method using a support such as an endless belt or a drum, the film is likely to be wrinkled or scratched, which hinders transparency, surface smoothness, and optical characteristics.
(4) In the method in which polyamic acid is thermally imidized on the support to obtain a film, the wettability of the support peeling surface increases (contact angle decreases) after the first cycle, and the temperature is high to recover the surface state. The production efficiency is not good because the heat treatment is required.
(5) In the method of obtaining a film by thermal imidization of polyamic acid, it is necessary to treat the film at a high temperature of 300 ° C. or higher, and transparency and optical properties cannot be realized.

  With the progress of miniaturization, weight reduction, and higher functionality of electronic information equipment, etc., films used for electrical / electronic materials, opto-device materials, etc. have better heat resistance, transparency, surface smoothness, and optical properties. Is required. Further, as electronic information devices and the like are reduced in size and weight, thinner films are required.

  Accordingly, an object of the present invention is to provide a method for efficiently producing a polyimide film excellent in heat resistance, transparency, surface smoothness, and optical properties with a high yield.

  As a result of intensive studies to achieve the above object, the present inventors have found an efficient method for producing a polyimide film having excellent heat resistance, transparency, surface smoothness, and optical properties. That is, the present invention has the following configuration.

The manufacturing method of the polyimide-type film which has a process (A)-a process (C) and whose surface roughness (Rz) is less than 0.08 micrometer.
Step (A): Solvent-soluble resin A is laminated on part or all of the surface of a metal material having a specular gloss of 200 or more and a surface roughness (Rz) of 0.5 μm or less, and a metal laminate Step of obtaining A Step (B): Step of obtaining metal laminate B by further laminating polyimide resin B different from solvent-soluble resin A on the surface of solvent-soluble resin A layer of metal laminate A ): Step of peeling the polyimide resin B layer from the metal laminate B to obtain a polyimide film

  The solvent-soluble resin A is preferably a polyamideimide resin A1 or a polyamide resin A2.

The polyamide-imide resin A1 is preferably the following (i).
(I) The acid component constituting the polyamideimide resin A is trimellitic anhydride, benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride, and biphenyl-3,3 ′, 4,4 ′. -One or more compounds selected from the group consisting of tetracarboxylic dianhydrides as a main component

The polyamide resin A2 is preferably the following (iv).
(Iv) The acid component constituting the polyamide resin A2 is mainly composed of one or more compounds selected from the group consisting of terephthalic acid, isophthalic acid, and 1,4-cyclohexanedicarboxylic acid.

It is preferable that the polyamideimide resin A1 and / or the polyamide resin A2 is further the following (ii) and / or (iii).
(Ii) 3,3′-dimethyl-4,4′-di, wherein the diamine component constituting the polyamideimide resin A is 3,3′-dimethyl-4,4′-diaminobiphenyl or a corresponding diisocyanate Isocyanatobiphenyl as a main component (iii) In N-methyl-2-pyrrolidone (polymer concentration 0.5 g / dl), logarithmic viscosity at 30 ° C. is 0.3 dl / g or more and 3.5 dl / g or less Must have a molecular weight equivalent to

It is preferable that the polyamide-imide resin A1 includes at least one structure selected from the group consisting of the following formula (1), formula (2), and formula (3) as a structural unit.

It is preferable that the said polyamide resin A2 contains 1 or more types of structures chosen from the group which consists of following formula (4) and Formula (5) as a structural unit.

  It is preferable that the polyamide-imide resin A1 and the polyamide resin A2 are crosslinked with an epoxy resin.

It is preferable that the metal material has a Young's modulus of 50 kN / mm ² or more and a thickness of 30 μm or more.

  The acid component constituting the polyimide resin B is cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride. It is preferable that the main component is a hydrogenated product of 1,1′-bicyclohexane-3,3 ′, 4,4′-tetracarboxylic acid-3,3 ′, 4,4′-dianhydride. .

The polyimide-type film obtained by the manufacturing method in any one of the said which is 1 or more types chosen from the group which consists of following (a), (b), (c), and (d).
(A) Surface roughness (Rz) is less than 0.08 μm (b) Glass transition point is 180 ° C. or higher and 350 ° C. or lower (c) Light transmittance at a wavelength of 400 nm is 60% or higher and 90% or lower (d) Haze value Is 0.1 or more and 2.0 or less

  A flexible metal-clad laminate using the polyimide film.

  By having a specific process, the present invention can efficiently produce a polyimide film having a surface roughness (Rz) of less than 0.08 μm with a high yield. Since the polyimide film obtained by the production method of the present invention is excellent in heat resistance, transparency, surface smoothness, and optical properties, it is industrially superior.

  Hereinafter, the manufacturing method of the polyimide-type film concerning embodiment of this invention is demonstrated.

The manufacturing method of the polyimide-type film of this invention has a process (A)-a process (C).
Step (A): Solvent-soluble resin A different from the raw material of the polyimide film on part or all of the surface of the metal material having a specular gloss of 200 or more and a surface roughness (Rz) of 0.5 μm or less Step of obtaining metal laminate A Step (B): A polyimide resin B as a raw material for the polyimide film is further laminated on the surface of the solvent-soluble resin A of the metal laminate, and the metal laminate B is obtained. Step (C): Step of peeling off only the polyimide resin B layer from the metal laminate B to obtain a polyimide film

  Since it has the above-mentioned process, the surface of the polyimide film that is in contact with the solvent-soluble resin A layer has a very smooth surface roughness (Rz) of less than 0.08 μm and is excellent in heat resistance, transparency, and optical properties. A film can be obtained.

Hereinafter, the manufacturing method of the present invention will be described separately for each process.
<<< Process (A) >>>
In the step (A), a part of or the entire surface of the metal material having a specular gloss of 200 or more and a surface roughness (Rz) of 0.5 μm or less is coated with a raw material for the polyimide film (acid component and / or A diamine component), a solvent-soluble resin A having a different composition or physical properties, and a metal laminate A is obtained.

<Metal material>
The metal material used for this invention becomes a support body for producing the polyimide-type film of this invention. Therefore, the metal material needs to have a smooth surface (surface on which the solvent-soluble resin A is laminated). Smoothness can be expressed by specular gloss and surface roughness. As the specular gloss, the specular gloss at an incident angle of 20 ° measured according to JIS Z-8741 (1997) is required to be 200 or more, preferably 400 or more, more preferably 500 or more. Yes, more preferably 600 or more. Although an upper limit is not specifically limited, It is 1000 or less industrially. Further, as the surface roughness, the surface roughness (Rz) measured according to JIS B-0601 (1994) needs to be 0.5 μm or less. Preferably it is 0.45 micrometer or less, More preferably, it is 0.4 micrometer or less, More preferably, it is 0.35 micrometer or less. Although a minimum is not specifically limited, Industrially, it is 0.001 micrometer or more. By satisfying the above range, the surface roughness of the solvent-soluble resin A side of the metal laminate A is 0.2 μm or less, and the surface smoothness, transparency, and optical properties of the polyimide film obtained in the present invention are improved. Application to optical materials and the like becomes easy.

Further, the metal material is preferably a metal material having a Young's modulus of 50 kN / mm ² or more and excellent in rigidity. More preferably, it is 60 kN / mm ² or more. The thickness is not particularly limited, but is preferably 1 μm or more and 1000 μm or less, more preferably 5 μm or more and 500 μm or less, further preferably 20 μm or more and 200 μm or less, and particularly preferably 30 μm or more and 150 μm or less. Can be used. If the rigidity or thickness of the metal material is out of the above range, the base material such as the solvent-soluble resin A or the metal material is deformed due to the effect of the solvent volume shrinkage during the heat treatment of the metal laminate A, and the smoothness cannot be maintained. Sometimes.

  The three-dimensional arithmetic average surface roughness (Sa) on the surface of the metal material (930 μm × 700 μm) is preferably 0.2 μm or less, more preferably 0.15 μm or less, and further preferably 0.1 μm. It is as follows. Although a minimum is not specifically limited, Industrially, it is 0.001 micrometer or more.

  The metal material is not particularly limited, and copper, SUS, aluminum, steel, nickel, and the like can be used. Moreover, the composite metal which compounded these, and the metal processed with other metals, such as zinc and a chromium compound, can also be used. The shape is not particularly limited, but a plate shape, a foil shape, and the like are preferable from the viewpoint of continuous productivity such as roll-to-roll processing.

  For example, in the case of a foil shape, although not particularly limited, copper foil, steel foil, SUS foil, aluminum foil, nickel foil, and the like can be used. Moreover, it can use also about the composite metal foil which compounded these, the metal foil processed with other metals, such as zinc and a chromium compound. The metal foil can be used in various shapes such as a cut sheet shape, a roll shape, or an endless belt shape. A roll shape is preferable, and its length is not particularly limited. Further, the width of the roll-shaped metal foil is not particularly limited, but is preferably 10 cm or more and 300 cm or less, preferably 15 cm or more and 250 cm or less, more preferably 20 cm or more and 200 cm or less, and particularly preferably 30 cm or more and 150 cm or less. .

<Solvent-soluble resin A>
The solvent-soluble resin A used in the present invention is an organic solvent that can withstand the heat history in the step (C) of obtaining the polyimide film in the step (C) and is excellent in smoothness and peelability. There is no particular limitation as long as it is a soluble resin. A preferred solvent-soluble resin A is polyamide-imide resin A1 or polyamide resin A2, and polyamide-imide resin A1 that is soluble in an organic solvent that is excellent in workability, heat resistance, and durability of metal laminate A and metal laminate B. Or it is preferable that it is polyamide resin A2. Moreover, when the polyimide resin B is a resin derived from polyamic acid, it is preferably a polyamide resin A2 that is not affected by the dehydration reaction during imidization.

  Solvent-soluble in the solvent-soluble resin A means being soluble in an organic solvent. Examples of the organic solvent include, but are not limited to, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, Examples include sulfolane, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, and cyclopentanone. Further, the solubility in an organic solvent is preferably 80% by mass or more at 25 ° C., more preferably 90% by mass or more, and further preferably 100% by mass.

  The solvent-soluble resin A used in the present invention is preferably a polyamideimide resin A1 or a polyamide resin A2, and is different from a polyimide resin B described later in raw materials (acid component and / or diamine component), composition or physical properties. is there. An acid component and a diamine component in the case where the solvent-soluble resin A is a polyamideimide resin A1 or a polyimide resin A2 will be described.

<Polyamideimide resin A1>
Polyamideimide resin A1 used for this invention can synthesize | combine an acid component and a diamine component in a solvent by usual methods, such as an acid chloride method, a low temperature solution polymerization method, a room temperature solution polymerization method, and an isocyanate method. In particular, a preferable production method is an isocyanate method for obtaining a polymer varnish that can be directly applied to a metal material, which is advantageous from the viewpoint of production cost.

<Acid component of polyamideimide resin A1>
The “acid component” of the polyamideimide resin A1 is not particularly limited, but trimellitic anhydride, 1,2,4-naphthalenetricarboxylic acid, diphenyl ether-3,3 ′, 4′-tricarboxylic acid, diphenylsulfone-3, 3 ′, 4′-tricarboxylic acid, benzophenone-3,3 ′, 4,4′-tetracarboxylic acid, biphenyl-3,3 ′, 4,4, ′-tetracarboxylic acid, diphenylether-3,3 ′, 4 , 4′-tetracarboxylic acid, alkylene glycol bis (trimellitate), bisphenol bis (trimellitate), pyromellitic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, naphthalene-2, 3, 6, 7 -Tetracarboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid, naphthalene-1,4,5,8-tetracarboxylic acid, etc. Monoanhydride, dianhydride, ester, and the like. Moreover, dicarboxylic acid components, such as isophthalic acid, terephthalic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, are mentioned. These can be used alone or as a mixture of two or more.

  Preferably, trimellitic anhydride, benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride, biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride, pyromellitic acid, Or it is diphenyl ether-3,3 ', 4,4'-tetracarboxylic acid, These can be used individually or in mixture of 2 or more types as an acid component. Among them, selected from the group consisting of trimellitic anhydride, benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride, and biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride It is preferable to use one or more kinds of compounds as main components. Here, the main component is preferably 50 mol% or more of 100 mol% of the total acid component of the polyamideimide resin A, more preferably 70 mol%, still more preferably 90 mol% or more, Even if it is 100 mol%, it does not interfere.

<Diamine component of polyamideimide resin A1>
The “diamine component” of the polyamideimide resin A1 is not particularly limited, but p-phenylenediamine, m-phenylenediamine, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 4,4′- Diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 3,4′-diaminobiphenyl, 3,3′-diaminobiphenyl, 3,3′-diaminobenzanilide, 4,4′-diaminobenzanilide, 4,4 '-Diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 2,6-tolylenediamine, 2,4-tolylenediamine, 4,4'-diaminodiphenyl Sulfide, 3,3′-diaminodiphenyl sulfide, 4,4′-diaminodiphenylpropane, 3,3′-di Aminodiphenylpropane, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, P-xylenediamine, m-xylenediamine, 1,4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine 2,7-naphthalenediamine, 2,2′-bis (4-aminophenyl) propane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1, 4-bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3- Aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] propane, 4,4′- (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′- Diaminobiphenyl, 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-diethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, or 3 , 3′-diethoxy-4,4′-diaminobiphenyl, or diisocyanates corresponding to these, can be used alone or as a mixture of two or more.

  Preferably, 3,3′-dimethyl-4,4′-diaminobiphenyl, 2,4-tolylenediamine, or 4,4′-diaminodiphenylmethane, or a corresponding diisocyanate, and these are used alone. Alternatively, it can be used as a mixture of two or more. Among these, 3,3′-dimethyl-4,4′-diaminobiphenyl or 3,3′-dimethyl-4,4′-diisocyanatobiphenyl (hereinafter referred to as “o-tolidine diisocyanate”), which is a diisocyanate corresponding thereto. Is sometimes referred to as "." It is preferable that the total amount of 3,3′-dimethyl-4,4′-diaminobiphenyl and / or o-tolidine diisocyanate is 50 mol% or more out of 100 mol% of the total diamine component of the polyamideimide resin A1, more Preferably it is 70 mol%, More preferably, it is 90 mol% or more, and even if it is 100 mol%, it does not interfere.

  Among the acid component and diamine component, the processability of the metal laminate A and the metal laminate B, the heat resistance and durability in the film forming process, and the transparency, surface smoothness, optical properties, and peeling of the polyimide film From the viewpoint of properties, the following components are preferably used. That is, as an acid component, from trimellitic anhydride, benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride, and biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride Using one or more compounds selected from the group consisting of 3,3′-dimethyl-4,4′-diaminobiphenyl and / or o-tolidine diisocyanate as the diamine component.

  Hereinafter, as an example of a preferred embodiment of the acid component, trimellitic anhydride, benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride and biphenyl-3,3 ′, 4,4′-tetracarboxylic Disclose the mixing ratio of the acid dianhydride. If the mixing ratio shown below is basically excellent in solubility in a solvent, the metal laminate A can be obtained simply by applying a polyamide-imide resin A1 solution to a metal material and drying, and a polyimide precursor. It is not necessary to carry out a condensation reaction at a high temperature after laminating. Therefore, it is excellent in the workability of the metal laminate A and the metal laminate B, and the productivity, surface smoothness, transparency, optical properties, and peelability of the polyimide film.

  First, the ratio of biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride to benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride is determined by biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride / benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride = 1/99 to 99/1 (molar ratio) is preferred, more preferably 30 / 70 to 70/30 (molar ratio).

  Next, a mixture of {biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride and benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride} and trimellit anhydride The ratio of the acid was {biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride + benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride} / trimellitic anhydride = 50/50 to 5/95 (molar ratio) is preferable, and 40/60 to 10/90 (molar ratio) is more preferable.

  The diamine component is contained in an amount of 50 mol% or more and 100 mol% or less, preferably 70 mol% or more and 100 mol% or less with respect to 100 mol% of the mixture of the acid components. Within these ranges, the processability of the metal laminate A and the metal laminate B, the heat resistance and durability in the film forming step, and the surface smoothness, transparency, optical properties, and peelability of the polyimide film Excellent.

  Further, as the polyamideimide resin A1, it is more preferable to use a compound containing one or more structures selected from the group consisting of the following formulas (1), (2), and (3) as structural units.

<Polyamide resin A2>
The polyamide resin A2 used in the present invention can be synthesized in a solvent by an ordinary method such as an acid chloride method, a low temperature solution polymerization method, a room temperature solution polymerization method, or an isocyanate method. In particular, a preferable production method is an isocyanate method for obtaining a polymer varnish that can be directly applied to a metal material, which is advantageous from the viewpoint of production cost.

<Acid component of polyamide resin A2>
The “acid component” of the polyamide resin A2 is not particularly limited, but dicarboxylic acid components such as terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, biphenyldicarboxylic acid, diphenyletherdicarboxylic acid, and diphenylsulfonedicarboxylic acid. Can be mentioned. These can be used alone or as a mixture of two or more.

  Preferred are terephthalic acid, isophthalic acid, and 1,4-cyclohexanedicarboxylic acid, and these can be used alone or as a mixture of two or more. Among these, it is preferable that isophthalic acid is a main component. Here, the main component is preferably contained in an amount of 50 mol% or more, more preferably 70 mol%, and still more preferably 90 mol% or more, out of 100 mol% of the total acid component of the polyamide resin A. Even if it is mol%, it does not interfere.

<Diamine component of polyamide resin A>
In addition, the “diamine component” of the polyamide resin A is not particularly limited, but the diamine component mentioned in the polyamideimide resin A1 or a diisocyanate corresponding to these may be used alone or as a mixture of two or more. Can do.

  Among the acid component and diamine component, the processability of the metal laminate A and the metal laminate B, the heat resistance and durability in the film forming process, and the transparency, surface smoothness, optical properties, and peeling of the polyimide film From the viewpoint of properties, the following components are preferably used. That is, as the acid component, one or more compounds selected from the group consisting of terephthalic acid, isophthalic acid, and 1,4-cyclohexanedicarboxylic acid are used, and 3,3′-dimethyl-4, 4'-diaminobiphenyl and / or o-tolidine diisocyanate.

  Below, the mixing ratio of isophthalic acid and 1,4-cyclohexanedicarboxylic acid is disclosed as an example of a preferred embodiment of the acid component. If the mixing ratio shown below is basically excellent in solubility in a solvent, the metal laminate A can be obtained simply by applying a polyamide resin A2 solution to a metal material and drying it, and it undergoes a condensation reaction at a high temperature. There is no need. Therefore, it is excellent in the workability of the metal laminate A and the metal laminate B, and the productivity, surface smoothness, transparency, optical properties, and peelability of the polyimide film.

  The ratio of isophthalic acid and 1,4-cyclohexanedicarboxylic acid is preferably isophthalic acid / 1,4-cyclohexanedicarboxylic acid = 1/99 to 99/1 (molar ratio), more preferably 30/70. ~ 90/10 (molar ratio).

  The diamine component is contained in an amount of 50 mol% or more and 100 mol% or less, preferably 70 mol% or more and 100 mol% or less with respect to 100 mol% of the mixture of the acid components. Within these ranges, the processability of the metal laminate A and the metal laminate B, the heat resistance and durability in the film forming step, and the surface smoothness, transparency, optical properties, and peelability of the polyimide film Excellent.

  Further, as the polyamide resin A2, it is more preferable to use a compound containing as a structural unit one or more structures selected from the group consisting of the following formulas (4) and (5).

  The polyamideimide resin A1 and the polyamide resin A2 can be obtained by a copolymerization reaction between the acid component and the diamine component in an organic solvent. Examples of the organic solvent include, but are not limited to, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, Examples include sulfolane, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, cyclopentanone, and the like, preferably N-methyl-2-pyrrolidone and N, N-dimethylacetamide. The reaction temperature is usually preferably from 10 ° C to 200 ° C, more preferably from 50 ° C to 150 ° C, and still more preferably from 100 ° C to 120 ° C. The reaction time depends on the reaction temperature and can be appropriately set, but is usually preferably 1 hour or longer and 24 hours or shorter, more preferably 2 hours or longer and 15 hours or shorter, and further preferably 3 hours or longer and 10 hours or shorter. . The polymerization reaction may be performed in the presence of a catalyst for the reaction between the isocyanate and the active hydrogen compound, for example, a tertiary amine, an alkali metal compound, or an alkaline earth metal compound. For example, the reaction may be performed in the presence of diazabicycloundecene as a tertiary amine.

  The solvent-soluble resin A has a molecular weight corresponding to 0.3 dl / g or more and 3.5 dl / g or less in N-methyl-2-pyrrolidone (polymer concentration 0.5 g / dl) as a logarithmic viscosity at 30 ° C. Those are preferred. The molecular weight is more preferably 1.0 dl / g or more and 3.0 dl / g or less, and still more preferably 1.7 dl / g or more and 2.5 dl / g or less. When the logarithmic viscosity is 0.3 dl / g or more, the metal laminate A is excellent in heat resistance and mechanical properties, and has good heat resistance and durability in the film forming process. The peelability is also improved. If it exceeds 3.50 dl / g, the solution viscosity becomes high, so that it may be difficult to form the metal laminate A itself.

<Varnish of solvent-soluble resin A>
The aforementioned solvent-soluble resin A is laminated on part or all of the metal material. If it is part or all, it may be single-sided or laminated on both sides. The solvent-soluble resin A may be a solution (varnish-like).

Although it does not specifically limit as a solvent for manufacturing solvent-soluble resin A solution (varnish), You may use the solvent used by the polymerization reaction as it is in the said polyamideimide resin A1 and polyamide resin A2. Specifically, for example, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, cyclopentanone, and the like, preferably N-methyl-2-pyrrolidone and N, N-dimethylacetamide.
Some of these can be replaced with hydrocarbon organic solvents such as toluene and xylene, ether organic solvents such as diglyme, triglyme and tetrahydrofuran, and ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone.

  If necessary, the solvent-soluble resin A of the present invention is used for the purpose of improving various properties of the metal laminate A and the metal laminate B, such as mechanical properties, electrical properties, slipperiness, and flame retardancy. Other resins, organic compounds, and inorganic compounds may be mixed or reacted with the solution. For example, lubricants (silica, talc, silicone, etc.), flame retardants (phosphorus, triazine, aluminum hydroxide, etc.), stabilizers (antioxidants, UV absorbers, polymerization inhibitors, etc.), organic and inorganic fillers (Talc, titanium oxide, fluoropolymer fine particles, pigments, dyes, calcium carbide, etc.), leveling agents (polyester-modified polydimethylsiloxane solution, polyether-modified polydimethylsiloxane solution, etc.), other silicone compounds, fluorine compounds, isocyanate compounds , Block isocyanate compounds, acrylic resins, urethane resins, polyester resins, polyamide resins, epoxy resins, phenolic resins and organic compounds, or these curing agents, silicon oxide, titanium oxide, calcium carbonate, iron oxide and other inorganic materials The compound should not interfere with the object of this invention. It can be used in combination in the range.

  Moreover, in the range which does not impair the effect of this invention, in addition to solvent soluble resin A, you may use together resin which can endure the heat history in a film-forming process. Although not particularly limited, for example, a polyimide resin, a polyamideimide resin, a polyesterimide resin, a polybenzimidazole resin, an aromatic polyester resin, or polyparabanic acid can be used, and one or more of these can be blended. .

  In particular, when the solvent-soluble resin A is a polyamideimide resin A1 or a polyamide resin A2, it is preferably crosslinked with a curable resin such as an epoxy resin or an isocyanate resin. By crosslinking with these curable resins, it can be expected that the performance of the polyimide film such as peelability is improved. Among the curable resins, epoxy resins are particularly preferable, and those that are commercially available are not particularly limited. However, brominated epoxy resin Brene (manufactured by Nippon Kayaku Co., Ltd.), phenol novolac type epoxy resin jER ( Registered trademark 152 (manufactured by Mitsubishi Chemical Corporation), jER154 (manufactured by Mitsubishi Chemical Corporation), bisphenol A type epoxy resin jER828 (manufactured by Mitsubishi Chemical Corporation), and the like can be suitably used.

  When the solvent-soluble resin A is a polyamideimide resin A1, the amount of the epoxy resin is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 2 parts by mass with respect to 100 parts by mass of the polyamideimide resin A1. Part to 10 parts by mass, more preferably 3 parts to 8 parts by mass. If it is 1 part by mass or more, the crosslinking reaction of the polyamideimide resin A is sufficient, and the effect of improving the peelability of the polyimide film is great. Moreover, if it is 40 mass parts or less, it is excellent in heat resistance and a mechanical characteristic.

  Further, when the solvent-soluble resin A is polyimide resin A2, the amount of the epoxy resin is preferably 1 equivalent or more and 10 equivalents or less, more preferably 1 equivalent with respect to the acid value 1 of the polyamide resin A2. It is 5 equivalents or less, more preferably 2 equivalents or more and 3 equivalents or less. If it is 1 equivalent or more, the crosslinking reaction of the polyamide resin A2 is sufficient, and the effect of improving the peelability of the polyimide film is great. Moreover, if it is 10 equivalent or less, it is excellent in heat resistance and mechanical characteristics.

  Further, the solvent-soluble resin A is improved in wettability with respect to the metal material of the solvent-soluble resin A by adding a silicone-based surface conditioner such as a polyester-modified polydimethylsiloxane solution, polyether-polyester-modified polydimethylsiloxane, or polyether-modified polydimethylsiloxane. It is also preferable to mix or react for the purpose of improving fluidity and leveling. Thereby, it can be expected that performance such as surface smoothness of the metal laminate A is improved. Examples of the commercially available polyester-modified polydimethylsiloxane solution include BYK (registered trademark) -370 and BYK-371, and examples of the polyether-polyester-modified polydimethylsiloxane include BYK-375. Examples of the modified polydimethylsiloxane include BYK-377 (all manufactured by Big Chemie Japan Co., Ltd.). Especially preferably, BYK-370 etc. can be used conveniently.

  The solid content concentration of the solvent-soluble resin A solution (varnish) thus obtained can be selected from a wide range, but is preferably 5% by weight or more and 40% by weight or less because of excellent workability. More preferably, it is 8 wt% or more and 20 wt% or less.

<Metal laminate A>
The metal laminate A used in the present invention is a laminate of two or more layers in which the solvent-soluble resin A layer is laminated on part or all of a metal material. In producing the metal laminate A, it is preferable that the solvent-soluble resin A solution is directly applied to a part or all of the metal material and dried. The application method is not particularly limited, and a conventionally well-known method can be applied. For example, the viscosity of the solvent-soluble resin A solution, which is a coating solution, is adjusted by a roll coater, a knife coater, a doctor, a blade coater, a gravure coater, a die coater, a reverse coater, etc., and then can be directly applied to a metal material.

  There are no particular limitations on the drying conditions after coating, but the initial drying temperature is 70 ° C to 130 ° C lower than the boiling point (Tb (° C)) of the solvent used in the solvent-soluble resin A solution, preferably 80 ° C to 120 ° C. A low temperature is good. In other words, the initial drying temperature may be (Tb-70) ° C. or lower (Tb-130) ° C. or higher, and preferably (Tb-80) ° C. or lower (Tb-120) ° C. or higher. If the initial drying temperature is (Tb-70) ° C. or lower (Tb-130) ° C. or higher, foaming hardly occurs on the coated surface, and unevenness of the residual solvent in the thickness direction of the solvent-soluble resin A layer is reduced. The drying efficiency in the heat treatment step is improved.

  For example, when the solvent used in the solvent-soluble resin A solution is N-methyl-2-pyrrolidone, the boiling point (Tb (° C.)) of the solvent is 204 ° C., so that it is 74 ° C. or higher and 134 ° C. or lower, preferably Initial drying is preferably performed at a temperature of 84 ° C. or higher and 124 ° C. or lower.

  Moreover, when using 2 or more types of mixed solvents, it is preferable to set the said temperature on the basis of the solvent with the highest boiling point.

  The time required for the initial drying may be an effective time for the solvent remaining rate in the coating film to be about 5% by weight to 40% by weight under the above temperature condition, but it may be about 1 minute to 30 minutes. That's fine. Preferably, it is about 2 minutes or more and 15 minutes or less.

  In addition, after the initial drying, it is preferable to further dry (also referred to as heat treatment) at a temperature close to or higher than the boiling point of the solvent.

There are no particular limitations on the heat treatment conditions, and drying may be performed at a temperature near or above the boiling point of the solvent. Although it depends on the resin composition of the solvent-soluble resin A, when the solvent-soluble resin A is a polyamideimide resin A1, there is little deterioration reaction, the polyamideimide resin A1 layer does not become brittle, can be dried in a short time, and has good productivity. The range is 150 ° C. or higher and 500 ° C. or lower, preferably 250 ° C. or higher and 400 ° C. or lower. When the solvent-soluble resin A is a polyamide resin A2, the temperature range in which the polyamide resin A2 layer is less brittle and the polyamide resin A2 layer is not fragile, can be dried in a short time, and has good productivity is 150 ° C. or higher and 400 ° C. or lower. Is 250 ° C. or higher and 350 ° C. or lower.
The time required for the heat treatment may be an effective time at which the solvent remaining rate in the coating film is eliminated under the above-described temperature condition, but is about several minutes to several tens of minutes.

The heat treatment may be performed under an inert gas atmosphere or under reduced pressure. The inert gas is not particularly limited, and examples thereof include nitrogen, carbon dioxide, helium, and argon, but it is preferable to use easily available nitrogen. It is desirable to reduce the oxygen concentration to 0.5% by volume or less, more preferably to 0.1% by volume or less. Moreover, when performing under reduced pressure, it is preferable to carry out under the pressure of about 10 < ^-5 > Pa or more and 10 < ³ > Pa or less, Preferably about 10 < ^-1 > Pa or more and 200 Pa or less.

  There are no particular limitations on the method for both initial drying and heat treatment, but continuous processing can be performed by a conventionally known method such as a roll support method or a floating method. Moreover, continuous heat treatment in a heating furnace such as a tenter type is also possible.

The thickness of the solvent-soluble resin A layer in the metal laminate A can be selected from a wide range, but the thickness after initial drying and heat treatment (hereinafter also referred to as absolutely dry) is preferably 5 μm or more and 1000 μm or less, preferably 7 μm or more. It is preferably 200 μm or less, more preferably 10 μm or more and 50 μm or less.
If the thickness is 5 μm or more and 1000 μm or less after absolute drying, mechanical properties and handling properties are good, surface smoothness and optical properties are also advantageous, and processability (drying properties, coating properties, and conveyance) Etc.) are also improved. In this invention, since it has specific process (A)-(C), even if the thickness of solvent-soluble resin A layer is thin, the polyimide-type film whose surface roughness (Rz) is less than 0.08 micrometer can be obtained. .
Moreover, you may perform a surface treatment as needed. For example, surface treatments such as hydrolysis, corona discharge, low temperature plasma, and physical roughening can be performed.

  Thus, a metal laminate A having a smooth surface of the solvent-soluble resin A layer can be obtained. The preferable surface roughness (Rz) of the surface of the solvent-soluble resin A layer in the metal laminate A is 0.2 μm or less, more preferably 0.15 μm, still more preferably 0.1 μm or less, and particularly preferably 0.8. It is 05 μm or less. Although a minimum is not specifically limited, Industrially, it is 0.01 micrometer or more. Further, by increasing the thickness of the solvent-soluble resin A layer (5 μm or more and less than 10 μm), the surface roughness (Rz) can be 0.15 μm or less, and by increasing the thickness (10 μm or more), it can be 0.11 μm or less. If the surface roughness (Rz) of the metal laminate A is 0.2 μm or less, the surface smoothness, transparency, and optical properties of the polyimide film obtained by the production method of the present invention will be improved, and it will be applied to optical materials and the like. Becomes easy. For example, since the haze value is 1.0 or less, it is easy to achieve the object of the present invention. In a general polyimide film manufacturing method, the surface roughness (Rz) of a support such as an endless belt or a drum is about 0.5 μm. Therefore, it can be said that the metal laminate A of the present invention is clearly smooth.

<<< Process (B) >>>
The step (B) is a step of obtaining a metal laminate B by further laminating a polyimide resin B different from the solvent-soluble resin A on the surface of the solvent-soluble resin A layer of the metal laminate A.

<Polyimide resin B>
The polyimide resin B used in the present invention is different from the solvent-soluble resin A in raw materials (acid component and / or diamine component), composition or physical properties. A polyimide resin B that is superior in heat resistance, transparency, surface smoothness, optical properties, and peelability from a conventional polyimide film and can produce a thinner polyimide film will be described.

  The polyimide resin B is basically not particularly limited as long as it is a raw material, composition or physical property different from that of the solvent-soluble resin A and can withstand the heat resistance in the film forming step. Preferably, from the surface smoothness, transparency, optical properties, and peelability of the polyimide film, polyamideimide resin, polyesterimide resin, or solvent-soluble polyimide resin that does not undergo imidization reaction after lamination or imidization reaction There are few partially imidized polyimide resins and polyamic acids which are polyimide precursors.

  The production of the polyimide resin B is the same as in the polyamideimide resin A1 and polyamide resin A2, and the acid component and the diamine component are mixed in a solvent in an ordinary manner such as an acid chloride method, a low temperature solution polymerization method, a room temperature solution polymerization method, and an isocyanate method. It can be synthesized by the method. In particular, a preferable production method is an isocyanate method for obtaining a polymer varnish that can be directly applied to the metal laminate A, which is advantageous from the viewpoint of production cost and the like.

<Acid component of polyimide resin B>
The “acid component” of the polyimide resin B is not particularly limited, but 1,2,4-naphthalene tricarboxylic acid, diphenyl ether-3,3 ′, 4′-tricarboxylic acid, diphenylsulfone-3,3 ′, 4 ′. A monohydride such as tricarboxylic acid or trimellitic acid, a dianhydride, an esterified product or a hydrogenated product of the above monomer such as hexahydrotrimellitic acid; 4,4 ′-(hexafluoroisopropylidene) diphthalic acid, Benzophenone-3,3 ′, 4,4′-tetracarboxylic acid, biphenyl-3,3 ′, 4,4′-tetracarboxylic acid, diphenylether-3,3 ′, 4,4′-tetracarboxylic acid, alkylene glycol Bis (trimellitate), bisphenol bis (trimellitate), 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, naphtha Monoanhydrides such as len-2,3,6,7-tetracarboxylic acid, naphthalene-1,2,4,5-tetracarboxylic acid, naphthalene-1,4,5,8-tetracarboxylic acid, pyromellitic acid , Dianhydrides, esterified products, or hydrogenated products of the above monomers such as hexahydropyromellitic acid; isophthalic acid, terephthalic acid, biphenyldicarboxylic acid, diphenyletherdicarboxylic acid, dicarboxylic acid component of diphenylsulfonedicarboxylic acid, or cyclohexanedicarboxylic acid And the like. These can be used alone or as a mixture of two or more.

  Preferably, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (hereinafter also referred to as H-TMA), benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride Hydrogenated product (hereinafter also referred to as H-BPDA), or 1,1′-bicyclohexane-3,3 ′, 4,4′-tetracarboxylic acid-3,3 ′, 4,4′-dianhydride (Hereinafter also referred to as H-BTDA), and these can be used alone or as a mixture of two or more. Of these, H-TMA, H-BTDA or H-BPDA is preferred as the main component. Here, the main component is preferably 50 mol% or more of 100 mol% of the total acid component of the polyimide resin B, more preferably 70 mol%, still more preferably 90 mol% or more, Even if it is 100 mol%, it does not interfere.

<Diamine component of polyimide resin B>
Further, the “diamine component” of the polyimide resin B is not particularly limited, but p-phenylenediamine, m-phenylenediamine, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 4,4′-. Diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 3,4′-diaminobiphenyl, 3,3′-diaminobiphenyl, 3,3′-diaminobenzanilide, 4,4′-diaminobenzanilide, 4,4 '-Diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 2,6-tolylenediamine, 2,4-tolylenediamine, 4,4'-diaminodiphenyl Sulfide, 3,3′-diaminodiphenyl sulfide, 4,4′-diaminodiphenylpropane, 3,3′-diamidine Diphenylpropane, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, P-xylenediamine, m-xylenediamine, 1,4-naphthalenediamine, 1,5-naphthalenediamine, 2,6-naphthalenediamine, 2,7-naphthalenediamine, 2,2′-bis (4-aminophenyl) propane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4 -Bis (4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-amino Phenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] propane, 4,4′-bis ( 4-Aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-diethyl-4,4′-diaminobiphenyl 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-diethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3 ′ -Diethoxy-4,4'-diaminobiphenyl, trans-1,4-diaminocyclohexane, cis-1,4-diaminocyclohexane, 1,4-diaminocyclohexane (trans / cis mixture), 1,3-diaminocyclohexane, dicyclo Hexylmethane-4,4′-diamine (trans isomer, cis isomer, trans / cis mixture), isophorone diamine, 1,4-cyclohexane Bis (methylamine), norbornenediamine, 3,8-bis (aminomethyl) tricyclo [5.2.1.0] decane, 1,3-diaminoadamantane, 4,4′-methylenebis (2-methylcyclohexylamine) 4,4′-methylenebis (2-ethylcyclohexylamine), 4,4′-methylenebis (2,6-dimethylcyclohexylamine), 4,4′-methylenebis (2,6-diethylcyclohexylamine), 2 , 2-bis (4-aminocyclohexyl) propane, 2,2-bis (4-aminocyclohexyl) hexafluoropropane, 1,3-propanediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenedi Mining, 1,9-nonamethylenediamine, 2,2′-bis (trifluoromethyl) benzidine or their corresponding diisocyanates, or a mixture of two or more thereof can be used as the diamine component. .

  Preferably, hydrogenated diphenylmethane-4,4′-diisocyanate (hereinafter also referred to as H-MDI), hydrogenated m-xylene diisocyanate (hereinafter also referred to as H-XDI), t-1,4-diamino Examples thereof include alicyclic isocyanates such as cyclohexane, isophorone diisocyanate, and norbornene diisocyanate, and these can be used alone or a mixture of two or more thereof as a diamine component.

  When the total diamine component in the polyimide resin B is 100 mol%, the exemplified diamine component may be contained in an amount of 50 mol% to 100 mol%, and more preferably 70 mol% to 100 mol%. Good. Within these ranges, the heat resistance and durability in the film forming process are good, and the surface smoothness, transparency, optical properties, and peelability of the resulting polyimide film are improved.

  The polyimide resin B can be obtained by a copolymerization reaction between the acid component and the diamine component in an organic solvent. Examples of the organic solvent include, but are not limited to, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, Examples include sulfolane, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, and cyclopentanone, and these can be used alone or as a mixed solvent of two or more. Preferably, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, γ-butyrolactone, or a combination thereof. The reaction temperature is usually preferably from 10 ° C to 200 ° C, more preferably from 50 ° C to 150 ° C, and still more preferably from 100 ° C to 120 ° C. The reaction time depends on the reaction temperature and can be appropriately set, but is usually preferably 1 hour or longer and 24 hours or shorter, more preferably 2 hours or longer and 15 hours or shorter, and further preferably 3 hours or longer and 10 hours or shorter. . The polymerization reaction may be performed in the presence of a catalyst for the reaction between the isocyanate and the active hydrogen compound, for example, a tertiary amine, an alkali metal compound, or an alkaline earth metal compound. For example, it may be carried out in the presence of triethylenediamine as a tertiary amine.

  Polyimide resin B has a molecular weight corresponding to 0.3 dl / g or more and 3.5 dl / g or less in N-methyl-2-pyrrolidone (polymer concentration 0.5 g / dl) as a logarithmic viscosity at 30 ° C. Those having a molecular weight corresponding to 1.0 dl / g or more and 3.0 dl / g or less, more preferably 1.7 dl / g or more and 2.5 dl / g or less are more preferable. When the logarithmic viscosity is 0.3 dl / g or more, the mechanical properties are excellent and the peelability is improved. Moreover, if it is 3.50 dl / g or less, a shaping | molding process will be easy.

<Varnish of polyimide resin B>
The polyimide resin B used in the present invention is laminated on the surface of the solvent-soluble resin A layer of the metal laminate A. The polyimide resin B may be varnished. As a solvent for producing the polyimide resin B solution (varnish), the solvent used in the polymerization reaction may be used as it is. Specifically, for example, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethyl sulfoxide, γ-butyrolactone, cyclohexanone, cyclopentanone and the like can be mentioned, and these can be used alone or as a mixed solvent. Preferably, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, γ-butyrolactone, or a combination thereof. Some of these can be replaced with hydrocarbon organic solvents such as toluene and xylene, ether organic solvents such as diglyme, triglyme and tetrahydrofuran, and ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone.

  More preferred solvents are 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, N, N-dimethylacetamide, or combinations thereof. The combination of 1,3-dimethyl-2-imidazolidinone and γ-butyrolactone is most preferable from the peelability from the metal laminate A, and the mixing ratio (mass ratio) thereof is 1,3-dimethyl-2-imidazolidinone. / Γ-butyrolactone = 30 to 70/70 to 30 is preferable, and 40 to 50/60 to 50 is more preferable. By using at such a ratio, the adhesion between the solvent-soluble resin A and the polyimide resin B is relaxed, and the peelability is improved. Some of these can be replaced with hydrocarbon organic solvents such as toluene and xylene, ether organic solvents such as diglyme, triglyme and tetrahydrofuran, and ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone.

If necessary, other resins and organic compounds may be added to the polyimide resin B solution for the purpose of improving various properties of the polyimide film such as mechanical properties, electrical properties, slipperiness, and flame retardancy. , And inorganic compounds may be mixed or reacted.
For example, lubricant (silica, talc, silicone, etc.), flame retardant (phosphorus, triazine, aluminum hydroxide, etc.), stabilizer (antioxidant, ultraviolet absorber, polymerization inhibitor, etc.), plating activator, organic And inorganic fillers (talc, titanium oxide, fluoropolymer fine particles, pigments, dyes, calcium carbide, etc.), leveling agents (polyester-modified polydimethylsiloxane solution, polyether-modified polydimethylsiloxane solution, etc.), other silicone compounds, Fluorine compound, isocyanate compound, block isocyanate compound, acrylic resin, urethane resin, polyester resin, polyamide resin, epoxy resin, resin such as phenol resin and organic compound, or curing agents thereof, silicon oxide, titanium oxide, calcium carbonate, Inorganic compounds such as iron oxide It can be used in combination as long as the purpose is not impaired.

  The solid content concentration of the polyimide resin B solution (varnish) thus obtained can be selected from a wide range, but is preferably 5% by weight or more and 40% by weight or less because of excellent workability. More preferably, it is particularly preferably 8 wt% or more and 20 wt% or less.

<Metal laminate B>
The metal laminate B used in the present invention is a laminate of three or more layers in which a polyimide resin B is further laminated on the surface of the metal laminate A on which the solvent-soluble resin A is laminated (metal material / solvent-soluble resin A / Polyimide resin B). It is preferable that the metal laminate B is directly coated with the polyimide resin B solution on one side or both sides of the metal laminate A on which the solvent-soluble resin A is laminated and dried. The application method is not particularly limited, and a conventionally well-known method can be applied. For example, after adjusting the viscosity of the polyimide resin solution, which is a coating solution, using a roll coater, knife coater, doctor, blade coater, gravure coater, die coater, reverse coater, etc., it can be applied directly to the metal laminate.

  There are no particular limitations on the drying conditions after coating, but after initial drying at a temperature 70 to 130 ° C. lower than the boiling point (Tb (° C.)) of the solvent used in the polyimide resin B solution, near the boiling point of the solvent or above the boiling point It is preferable to further dry (heat treatment) at this temperature. More preferably, it is about 80-120 degreeC. In other words, the initial drying temperature is (Tb-70) ° C. or lower (Tb-130) ° C. or higher, preferably (Tb-80) ° C. or lower (Tb-120) ° C. or higher. When the initial drying temperature is (Tb-70) ° C. or lower (Tb-130) ° C. or higher, foaming hardly occurs on the coated surface, and the peelability from the metal laminate B is improved. The time required for the initial drying may be an effective time for the solvent remaining rate in the coating film to be about 5% by weight to 40% by weight under the above temperature conditions, but may be about 1 minute to 30 minutes. That's fine. Preferably, it is about 2 minutes or more and 15 minutes or less.

Also, the heating conditions are not particularly limited, and drying may be performed near the boiling point of the solvent or at a temperature equal to or higher than the boiling point. Although it depends on the resin composition of the polyimide resin B, the peelability from the metal laminate B, the transparency of the polyimide film, the surface smoothness, and the optical properties are good, the degradation reaction is small and the polyimide film is not fragile, The temperature range that can be dried in a short time and has good productivity is 100 ° C. or higher and 400 ° C. or lower, preferably 150 ° C. or higher and 350 ° C. or lower.
The time required for the heat treatment may be an effective time at which the residual ratio of the solvent in the coating film is eliminated under the above temperature condition, but is about several minutes to several tens of minutes.

  For example, it is possible to achieve both releasability, surface smoothness, optical properties, and transparency by drying at 330 to 340 ° C. × 10 to 30 minutes, but when dried at a temperature higher than this, the solvent-soluble resin in the metal laminate B Adhesive strength between A and the polyimide resin B applied thereon becomes stronger and the peelability is lowered, and the transparency is lowered and the film tends to yellow.

Drying may be performed under an inert gas atmosphere or under reduced pressure. The inert gas is not particularly limited, and examples thereof include nitrogen, carbon dioxide, helium, and argon, but it is preferable to use easily available nitrogen. In order to suppress the coloring of the polyimide film and obtain a colorless and transparent film, it is desirable to reduce the oxygen concentration to 0.5% or less, more preferably to 0.1% or less. Moreover, when performing under reduced pressure, it is preferable to carry out under the pressure of about 10 < ^-5 > Pa or more and 10 < ³ > Pa or less, Preferably about 10 < ^-1 > Pa or more and 200 Pa or less.

  There are no particular limitations on the method for both initial drying and heat treatment, but continuous processing can be performed by a conventionally known method such as a roll support method or a floating method. Moreover, continuous heat treatment in a heating furnace such as a tenter type is also possible.

In the present invention, the thickness of the polyimide resin B layer can be selected from a wide range, but the thickness after absolutely dry is about 1 μm or more and 100 μm or less, preferably about 10 μm or more and 50 μm or less. When the thickness is less than 1 μm, mechanical properties such as film strength and handling properties are inferior. On the other hand, when the thickness exceeds 100 μm, workability (drying property, coating property) and the like may be deteriorated.
Moreover, you may perform a surface treatment as needed. For example, surface treatment such as hydrolysis, corona discharge, low temperature plasma, physical roughening, and easy adhesion coating treatment can be performed.

<< Step (C) >>
Step (C) is a step in which only the polyimide resin B layer is peeled from the metal laminate B to obtain a polyimide film. The peeled polyimide resin B layer becomes a polyimide film.

According to the present invention, a polyimide film excellent in transparency, surface smoothness, optical characteristics, and heat resistance can be easily obtained simply by peeling the polyimide resin B layer from the metal laminate B. There is no limitation in the peeling method and it can peel easily by a conventionally well-known method. For example, it can manufacture by winding the metal laminated body A and a polyimide-type film on a separate roll, etc., peeling a polyimide-type film continuously after heat processing.
In particular, in the conventional film forming method, the surface smoothness itself is inferior, and scratches, wrinkles, or dents derived from the substrate are likely to enter, and even a thin film that cannot be used in optical applications can be easily produced. it can.

<< Characteristics of polyimide film >>
The polyimide-type film obtained by this invention is excellent in heat resistance, transparency, surface smoothness, and optical characteristics than the conventional film.

<Heat resistance>
The heat resistance is indicated by the glass transition point, but the glass transition point of the obtained polyimide film is preferably 180 ° C. or higher and 350 ° C. or lower, more preferably 200 ° C. or higher and 330 ° C. or lower, and still more preferably 230. It is at least 320 ° C.

<Surface smoothness>
The surface smoothness of the polyimide film can be indicated by the surface roughness (Rz) and the three-dimensional arithmetic average roughness (Sa). The surface roughness (Rz) is measured according to JIS B-0601 (1994). The three-dimensional arithmetic average roughness (Sa) is measured by a non-contact surface / layer cross-sectional shape measurement system.
The surface roughness (Rz) of the surface in contact with the solvent-soluble resin A layer of the polyimide film is less than 0.08 μm. It is preferably 0.07 μm or less, more preferably 0.06 μm or less, further preferably 0.05 μm or less, particularly preferably less than 0.05 μm, and most preferably 0.04 μm or less. Although a minimum is not specifically limited, Industrially, it is 0.001 micrometer or more. By setting the surface roughness (Rz) to less than 0.08 μm, the surface smoothness, transparency, and optical properties of the polyimide-based film are extremely improved, and application to optical materials and the like is facilitated.
The three-dimensional arithmetic average surface roughness (Sa) in the range of 930 μm × 700 μm of the surface in contact with the solvent-soluble resin A layer of the polyimide film is preferably 0.1 μm or less, more preferably It is 09 μm or less, more preferably 0.08 μm or less, and particularly preferably 0.07 μm or less. Although a minimum is not specifically limited, Industrially, it is 0.001 micrometer or more.

<Transparency and optical properties>
Transparency and optical properties are indicated by light transmittance. The light transmittance of the resulting polyimide film is preferably 60% or more and 90% or less, and more preferably 65% or more and 90% or less, at a wavelength of 400 nm, in accordance with JIS K-7361-1 (1997). Moreover, it is preferable that the haze value of the obtained polyimide-type film is 2.0 or less according to JISK-7136 (2000), More preferably, it is 1.0 or less. Although a minimum is not specifically limited, It is 0.1 or more industrially.

<Peelability>
The peelability when the polyimide resin B layer is peeled from the metal laminate B is indicated by the adhesive strength. The adhesive strength between the obtained polyimide film and the metal laminate is good because it can be easily peeled off if it is 1 N / cm or less, and very good if it is 0.5 N / cm or less. Moreover, although a minimum is not specifically limited, 0.01 N / cm or more is enough.

<Thickness of polyimide film>
The thickness of the polyimide film obtained by the present invention can be selected from a wide range, but it can be reduced to several μm as long as mechanical properties such as film strength can be maintained. Specifically, it is preferably 50 μm or less, more preferably 40 μm or less, and still more preferably 30 μm or less. Moreover, 5 micrometers or more are preferable, 8 micrometers or more are more preferable, and 10 micrometers or more are further more preferable.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not particularly limited by the examples. The evaluation method of the characteristic value in each example is as follows.

(Logarithmic viscosity)
A sample (solvent soluble resin A or polyimide resin B) is dissolved in N-methyl-2-pyrrolidone so that the polymer concentration is 0.5 g / dl, and the solution viscosity and solvent viscosity of the solution are 30 ° C. It was measured with a mold viscosity tube and calculated according to the following formula. V1 represents the solution viscosity, V2 represents the solvent viscosity, and V3 represents the concentration of the sample solution (0.5 g / dl).
Logarithmic viscosity (dl / g) = [ln (V1 / V2)] / V3

(Glass transition point (Tg), thermal expansion coefficient (CTE))
The obtained polyimide film was measured under the following conditions by TMA (thermal mechanical analysis) (trade name “EXSTAR TMA / SS 6000”, manufactured by Seiko Instruments Inc.) tensile load method. The inflection point of the obtained curve was defined as the glass transition temperature (Tg), and a tangent line was drawn in each of the low temperature region (glass region) and the high temperature region (rubber region) from Tg, and the temperature was calculated as the temperature at which these tangent lines intersect. The coefficient of thermal expansion (CTE) is a value indicating the rate of thermal expansion of the length and volume of an object with an increase in temperature per 1 K (° C.), and is an average value from 100 ° C. to 200 ° C.
Load: 1g
Sample size: 4 (width) x 20 (length) mm
Temperature increase rate: 10 ° C / min Atmosphere: Nitrogen

(Surface roughness (Rz))
According to JIS B 0601: 1994, the ten-point average roughness (Rz) was measured using a surface roughness measuring machine (trade name “E-35B”, manufactured by Tokyo Seimitsu Co., Ltd.).

(Three-dimensional arithmetic average roughness (Sa))
Three-dimensional arithmetic average roughness (Sa) was measured using a non-contact surface / layer cross-sectional shape measurement system (trade name “VertScan 2.0”, manufactured by Ryoka System Co., Ltd.).

(Specular gloss)
The specular gloss at an incident angle of 20 ° was measured using (trade name “Gloss Meter VG2000”, manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS Z 8741: 1997.

(Residual solvent ratio)
Residual solvent concentration in polyimide film is determined by weight reduction from 100 ° C to 350 ° C using a differential thermothermal gravimetric simultaneous measurement device (trade name "EXSTAR TG / DTA 6000", manufactured by Seiko Instruments Inc.) It was. All weight loss from 100 ° C to 350 ° C was considered as solvent volatilization.

(Peelability (adhesive strength))
A metal laminate in which a polyimide resin B varnish is further applied to the surface of the metal laminate A in which the solvent-soluble resin A is laminated on at least one side of the metal material and the solvent-soluble resin A is laminated. A test sample for B (150 mm long × 5 mm wide) was prepared. Next, the test sample was attached to a stainless steel plate (SUS plate) by using a double-sided tape (trade name “NW-K10”, manufactured by Nichiban Co., Ltd.) and reciprocating once with a 1 kg roller. The peelability (adhesion strength) was measured by peeling the polyimide film at an angle of 90 ° at a tensile speed of 50 mm / min and measuring the stress at that time as the adhesive force (N / cm).

(Light transmittance)
According to JIS K-7361-1: 1997, the light transmittance at a wavelength of 200 nm to 800 nm is measured with a spectrophotometer (trade name “UV-3150”, manufactured by Shimadzu Corporation), and the light transmittance at 400 nm is obtained. Compared.

(Haze)
According to JIS K 7136: 2000, it measured using the haze meter (Brand name "NDH2000", Nippon Denshoku Industries Co., Ltd. product).
In the evaluation, a haze value of 0.5 or less was evaluated as “◎”, 0.5 to 1.0 or less as ◯, 1.0 to 2.0 or less as Δ, and 2.0 as ×.

[Synthesis Example 1] Synthesis of Polyamideimide Resin A1 (Resin A1-1)
The following composition was added to the reaction vessel, heated to 100 ° C. under a nitrogen stream, and reacted at 100 ° C. for 8 hours.
1) Trimellitic anhydride: 153.7 g (80 mol%)
2) Benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride: 40.3 g (12.5 mol%)
3) Biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride: 22.1 g (7.5 mol%)
4) 3,3′-dimethyl-4,4′-diisocyanate biphenyl (o-tolidine diisocyanate): 264.3 g (100 mol%)
5) Diazabicycloundecene (catalyst): 1.0 g
6) N-methyl-2-pyrrolidone (purity 99.9%): 2500 g
Next, 1031 g of N-methyl-2-pyrrolidone (polymer concentration: 10% by weight) was added and cooled to room temperature. The logarithmic viscosity of the obtained polymer was 1.9 dl / g, and the solution viscosity at 25 ° C. (measured at 10 revolutions with a B-type viscometer) was 250 poise.

[Synthesis Example 2] Synthesis of polyamideimide resin A1 (resin A1-2)
The following composition was added to the reaction vessel, heated to 100 ° C. under a nitrogen stream, and reacted at 100 ° C. for 8 hours.
1) Trimellitic anhydride: 96.1 g (50 mol%)
2) Biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride: 147.1 g (50 mol%)
3) 3,3′-dimethyl-4,4′-diisocyanate biphenyl (o-tolidine diisocyanate): 264.3 g (100 mol%)
4) Diazabicycloundecene (catalyst): 1.5 g
5) N-methyl-2-pyrrolidone (purity 99.9%): 2377 g
Next, 430 g of N-methyl-2-pyrrolidone (polymer concentration 13% by weight) was added, and the mixture was cooled to room temperature. The logarithmic viscosity of the obtained polymer was 2.0 dl / g, and the solution viscosity at 25 ° C. (measured at 10 revolutions with a B-type viscometer) was 300 poise.

[Synthesis Example 3] Synthesis of polyamide resin A2 (resin A2-1)
The following composition was added to the reaction vessel, heated to 100 ° C. under a nitrogen stream, and reacted at 100 ° C. for 8 hours.
1) Isophthalic acid: 156.7 g (90 mol%)
2) 1,4-cyclohexanedicarboxylic acid: 18.0 g (10 mol%)
3) 3,3′-dimethyl-4,4′-diisocyanate biphenyl (o-tolidine diisocyanate): 263.1 g (100 mol%)
4) Diazabicycloundecene (catalyst): 1.6 g
5) N-methyl-2-pyrrolidone (purity 99.9%): 650 g
Next, 166.8 g of N-methyl-2-pyrrolidone (polymer concentration: 30% by weight) was added and cooled to room temperature. The logarithmic viscosity of the obtained polymer was 0.4 dl / g, and the solution viscosity at 25 ° C. (measured at 10 revolutions with a B-type viscometer) was 400 poise.

[Synthesis Example 4] Synthesis of polyamide resin A2 (resin A2-2)
The following composition was added to the reaction vessel, heated to 100 ° C. under a nitrogen stream, and reacted at 100 ° C. for 8 hours.
1) Isophthalic acid: 145.6 g (100 mol%)
2) 3,3′-dimethyl-4,4′-diisocyanate biphenyl (o-tolidine diisocyanate): 231.7 g (100 mol%)
3) Diazabicycloundecene (catalyst): 1.3 g
4) N-methyl-2-pyrrolidone (purity 99.9%): 557.4 g
Next, 142.9 g of N-methyl-2-pyrrolidone (polymer concentration 30% by weight) was added, and the mixture was cooled to room temperature. The logarithmic viscosity of the obtained polymer was 0.5 dl / g, and the solution viscosity at 25 ° C. (measured at 10 revolutions with a B-type viscometer) was 500 poise.

[Synthesis Example 5] Synthesis of polyimide resin B (resin B1)
The following composition was added to the reaction vessel, heated to 150 ° C. under a nitrogen stream, and reacted at 150 ° C. for 6 hours.
1) Cyclohexane-1,2,4-tricarboxylic acid-1, monoanhydride (H-TMA): 198.2 g (100 mol%)
2) 3,3′-dimethyl-4,4′-diisocyanate biphenyl: 264.3 g (100 mol%)
3) Triethylenediamine (catalyst): 2.2 g
4) 1,3-Dimethyl-2-imidazolidinone (purity 99.9%): 795.7 g
Next, 702.1 g of γ-butyrolactone (polymer concentration 20% by weight) was added, and the mixture was cooled to room temperature. The logarithmic viscosity of the obtained polymer was 0.8 dl / g, and the solution viscosity at 25 ° C. (measured at 10 revolutions with a B-type viscometer) was 500 poise.

[Synthesis Example 6] Synthesis of polyimide resin B (resin B2)
A reaction vessel was charged with 66.7 g (100 mol%) of isophorone diisocyanate, dissolved in 246 g of 1,3-dimethyl-2-imidazolidinone (purity 99.9%), and then stirred under a nitrogen stream. Gradually add 91.9 g (100 mol%) of powder of '-bicyclohexane-3,3', 4,4'-tetracarboxylic acid-3,3 ', 4,4'-dianhydride (H-BPDA). In addition, the mixture was reacted at 80 ° C. to 190 ° C. for 8 hours with stirring. Next, 283.2 g of γ-butyrolactone (polymer concentration: 20% by weight) was added and cooled to room temperature. The logarithmic viscosity of the obtained polymer was 0.5 dl / g, and the solution viscosity at 25 ° C. (measured at 10 revolutions with a B-type viscometer) was 300 poise.

[Synthesis Example 7] Synthesis of polyimide resin B (resin B3)
95.22 g of diester tetracarboxylic dianhydride obtained by reacting PTMG1000 (manufactured by Sanyo Chemical Industries, Ltd., molecular weight 1000) and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride in a reaction vessel 0.07 mol), cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride 5.95 g (0.03 mol), 4,4′-diphenylmethane diisocyanate 25.03 g (0.1 mol), After adding 0.1 g of potassium fluoride and dissolving it in 1,249.46 g of 1,3-dimethyl-2-imidazolidinone, it is made transparent by reacting at 80 ° C. to 190 ° C. for 8 hours with stirring under a nitrogen stream. A viscous polyesterimide solution was obtained. The logarithmic viscosity of the obtained polymer was 0.95 dl / g.

[Synthesis Example 8] Synthesis of polyimide resin B (resin B4)
24.8 g (100 mol%) of bis (3-aminophenyl) sulfone was placed in a reaction vessel, dissolved in 222 g of N-methyl-2-pyrrolidone, and then stirred with 1,1′-bicyclohexane under a nitrogen stream. −3,3′-4,4′-tetracarboxylic acid—30.6 g (100 mol%) of 3,3′-4,4′-dianhydride (H-BPDA) powder was gradually added at room temperature. By reacting for 15 hours, a transparent and viscous polyamic acid solution was obtained. The logarithmic viscosity of the obtained polyamic acid was 0.6 dl / g, and the solution viscosity at 25 ° C. (measured at 10 revolutions with a B-type viscometer) was 300 poise.

[Production Example 1]
The resin solution of resin A1-1 obtained in Synthesis Example 1 was applied to the treated surface (M surface) of an aluminum foil (3003 / H18, 20 ° specular gloss 447 manufactured by Nippon Electrolytic Co., Ltd.) having a thickness of 50 μm and a width of 540 mm. The film was continuously coated using a coating device so that the thickness after solvent removal was 30 μm. Subsequently, the film was continuously passed through a floating drying furnace having a length of 20 m set at 100 ° C. at a speed of 5 m / min and wound up. The residual solvent ratio of the obtained metal laminate A1-1 was 25% by weight.
The metal-clad laminate A1-1 thus obtained was further heat-treated continuously under nitrogen at 100 ppm oxygen concentration under heating conditions of 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and 300 ° C. for 30 minutes.

[Production Example 2]
The treated surface of the resin solution of resin A1-1 obtained in Synthesis Example 1 having a thickness of 11 μm and a width of 540 mm (CF-T9DA-SV, 20 ° specular gloss 660, manufactured by Fukuda Metal Foil Powder Co., Ltd.) A metal laminate A1-2 serving as a support was produced in the same manner as in Production Example 1 except that (M-plane) was used.

[Production Example 3]
A treated surface of a resin solution of resin A1-1 obtained in Synthesis Example 1 having a thickness of 15 μm and a width of 540 mm (tough pitch copper foil OFC-HX, manufactured by SH Copper Products Co., Ltd., 20 ° specular gloss 247) ( A metal laminate A1-3 serving as a support was produced in the same manner as in Production Example 1 except that the (M-plane) was used.

[Production Example 4]
The resin solution of resin A1-1 obtained in Synthesis Example 1 was used except that the treated surface (M surface) of SUS foil (HA manufactured by Nippon Metal Co., Ltd., 20 ° specular gloss 287) having a thickness of 30 μm and a width of 540 mm was used. Produced a metal laminate A1-4 as a support in the same manner as in Production Example 1.

[Preparation Examples 5 to 7]
The processed surface (M surface) of the resin solution of resin A1-1 obtained in Synthesis Example 1 having a thickness of 50 μm and a width of 540 mm (SUS metal (SHE-TA (BS) manufactured by Nippon Metal Co., Ltd., 20 ° specular gloss 687)) ) Were coated using a die coater so that the thickness after solvent removal was 10 μm (metal laminate A1-5), 20 μm (metal laminate A1-6), and 30 μm (metal laminate A1-7). Except for the above, metal laminates A1-5 to A1-7 serving as a support were produced in the same manner as in Production Example 1.

[Creation Example 8]
The treated surface (M surface) of the resin solution of the resin A1-2 obtained in Synthesis Example 2 having a thickness of 50 μm and a width of 540 mm (SHE-TA (BS) manufactured by Nippon Metal Co., Ltd., 20 ° specular gloss 687) A metal laminate A1-8 serving as a support was produced in the same manner as in Production Example 1 except that the film was coated using a die coater so that the thickness after solvent removal was 20 μm.

[Production Example 9]
The treated surface of the resin solution of resin A1-1 obtained in Synthesis Example 1 having a thickness of 18 μm and a width of 540 mm (USLP-SE-18, 20 ° specular gloss 0.3 by Nihon Denki Co., Ltd.) A metal laminate A1-9 serving as a support was produced in the same manner as in Production Example 1 except that the M surface was used.

[Production Example 10]
The resin solution of resin A2-1 obtained in Synthesis Example 3 is coated with a die coater on the treated surface (M surface) of a SUS foil (304 nanoBA, 20 ° specular gloss 1000 made by Nippon Metal Co., Ltd.) having a thickness of 120 μm and a width of 540 mm. The film was continuously coated so that the thickness after solvent removal was 30 μm. Subsequently, the film was continuously passed through a floating drying furnace having a length of 20 m set at 100 ° C. at a speed of 5 m / min and wound up. The residual solvent ratio of the obtained metal laminate A2-1 was 25% by weight.
The metal-clad laminate A2-1 thus obtained was further heat-treated continuously under nitrogen at 100 ppm oxygen concentration under heating conditions of 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and 300 ° C. for 30 minutes.

[Production Example 11]
The same as Production Example 10 except that the resin solution of Resin A2-1 obtained in Synthesis Example 3 was applied to a 50 μm thick, 540 mm wide SUS foil (304BA2, 20 ° specular gloss 310 by Nippon Metal Co., Ltd.). Thus, a metal laminate A2-2 serving as a support was produced.

[Production Example 12]
Production Example 10 except that the resin solution of Resin A2-1 obtained in Synthesis Example 3 was applied to an aluminum foil (3003 / H18, 20 ° specular gloss 447 manufactured by Nippon Electrolytic Co., Ltd.) having a thickness of 50 μm and a width of 540 mm. In the same manner as above, a metal laminate A2-3 serving as a support was produced.

[Production Example 13]
The treated surface of the resin solution of the resin A2-1 obtained in Synthesis Example 3 having a thickness of 11 μm and a width of 540 mm (CF-T9DA-SV, 20 ° specular gloss 660, manufactured by Fukuda Metal Foil Powder Co., Ltd.) A metal laminate A2-4 serving as a support was produced in the same manner as in Production Example 10 except that the coating was applied to (M surface).

[Production Example 14]
The resin solution of Resin A2-2 obtained in Synthesis Example 4 was applied to the treated surface (M surface) of a 120-μm-thick 540 mm-wide SUS foil (304 nanoBA, 20 ° specular gloss 1000 of Nippon Metal Co., Ltd.). Except for the above, a metal laminate A2-5 serving as a support was produced in the same manner as in Production Example 10.

[Production Example 15]
The resin surface of resin A2-1 obtained in Synthesis Example 3 was treated with an electrolytic copper foil having a thickness of 18 μm and a width of 540 mm (USLP-SE-18, 20 ° specular gloss of 0.3 manufactured by Nihon Denki Co., Ltd.) ( A metal laminate A2-6 serving as a support was produced in the same manner as in Production Example 10 except that the coating was applied to the (M surface).

[Example 1] Polyimide film B1-1
As a supporting substrate, the resin B1 obtained in Synthesis Example 5 is uniformly applied to the resin surface of the metal laminate A1-1 of Production Example 1 so that the thickness after drying becomes 30 μm, and heated at a temperature of 100 ° C. or lower. Dried. Then, the inside of the far-infrared heating system (RtoR type heat treatment apparatus heat manufactured by Noritake Engineering Co., Ltd.) was continuously conveyed. The temperature in the heating furnace (metal laminate B1-1 surface temperature) is 180 ° C for the first, second, and third zones, 250 ° C for the fourth zone, and 330 ° C for the fifth, sixth, and seventh zones (nitrogen). Flow rate 500L / min, oxygen concentration 100ppm, far-infrared plate heater upper surface, lower surface arrangement, irradiation distance 100mm, wavelength 5.6-1000μ, capacity 225kW, heater dimensions 150mm x 700mm), transport speed is 10 minutes each for drying time The metal laminate B1-1 was obtained in 5 minutes and 10 minutes. Thereafter, only the polyimide resin B1 layer of the metal laminate B1-1 was peeled off to obtain a polyimide film B1-1. The results are shown in Table 1. The haze value was 0.41.

[Example 2] Polyimide film B1-2
A polyimide-based resin B1 was formed in the same manner as in Example 1 except that the metal laminate A1-2 of Production Example 2 was used as the support substrate. The results of the obtained polyimide film B1-2 are shown in Table 1. The haze value was 0.45.

[Example 3] Polyimide film B1-3
A polyimide-based resin B1 was formed in the same manner as in Example 1 except that the metal laminate A1-3 of Production Example 3 was used as the support substrate. The results of the obtained polyimide film B1-3 are shown in Table 1. The haze value was 0.51.

[Example 4] Polyimide film B1-4
A polyimide-based resin B1 was formed in the same manner as in Example 1 except that the metal laminate A1-4 of Production Example 4 was used as the support base. The results of the obtained polyimide film B1-4 are shown in Table 1. The haze value was 0.55.

[Example 5] Polyimide film B1-5
A polyimide resin B1 was formed in the same manner as in Example 1 except that the metal laminate A1-5 of Preparation Example 5 (the thickness of the resin A1 was 10 μm) was used as the support substrate. The results of the obtained polyimide film B1-5 are shown in Table 1. The haze value was 0.46.

[Example 6] Polyimide film B1-6
A polyimide-based resin B1 was formed in the same manner as in Example 1 except that the metal laminate A1-6 of Preparation Example 6 (thickness of resin A1 of 20 μm) was used as the supporting substrate. The results of the obtained polyimide film B1-6 are shown in Table 1. The haze value was 0.57.

[Example 7] Polyimide film B1-7
A polyimide-based resin B1 was formed in the same manner as in Example 1 except that the metal laminate A1-7 of Preparation Example 7 (thickness of resin A1 of 30 μm) was used as the supporting substrate. The results of the obtained polyimide film B1-7 are shown in Table 1. The haze value was 0.37.

[Example 8] Polyimide film B1-8
A polyimide resin B1 was formed in the same manner as in Example 1 except that the metal laminate A1-8 of Preparation Example 8 (thickness 20 μm of Resin A1) was used as the support substrate. The results of the obtained polyimide film B1-8 are shown in Table 1. The haze value was 0.55.

[Example 9] Polyimide film B2-1
As a supporting substrate, the resin B2 obtained in Synthesis Example 6 is uniformly applied to the resin surface of the metal laminate A1-1 of Preparation Example 1 so that the thickness after drying becomes 30 μm, and heated at a temperature of 100 ° C. or lower. A polyimide resin B2 was formed in the same manner as in Example 1 except that it was dried. The results of the obtained polyimide film B2-1 are shown in Table 1. The haze value was 0.42.

[Example 10] Polyimide film B3-1
As a supporting substrate, the resin B3 obtained in Synthesis Example 4 is uniformly applied to the resin surface of the metal laminate A1-1 of Preparation Example 1 so that the thickness after drying becomes 30 μm, and heated at a temperature of 100 ° C. or lower. A polyimide resin B3 (polyesterimide) was formed in the same manner as in Example 1 except that it was dried. The results of the obtained polyimide film B3-1 are shown in Table 1. The haze value was 0.7.

[Example 11] Polyimide film B1-9
Resin B1 obtained in Synthesis Example 5 was continuously coated on the resin surface of metal laminate A2-1 of Production Example 10 using a die coater so that the thickness after solvent removal was 30 μm. Next, the laminate was passed by being continuously passed through a floating drying furnace having a length of 20 m set at 100 ° C. at a speed of 5 m / min to obtain a metal laminate B1-9. The thus obtained metal-clad laminate B1-9 was further heat-treated continuously under nitrogen at an oxygen concentration of 100 ppm at 200 ° C. for 30 minutes, 250 ° C. for 30 minutes, and 300 ° C. for 30 minutes.
Thereafter, only the polyimide resin B1 layer of the metal laminate B1-9 was peeled off to obtain a polyimide film B1-9. The results are shown in Table 2. The haze value was 0.35.

[Example 12] Polyimide film B1-10
A polyimide-based resin B1 was formed in the same manner as in Example 11 except that the metal laminate A2-2 of Production Example 11 was used as the support substrate. The results of the obtained polyimide film B1-10 are shown in Table 2. The haze value was 0.37.

[Example 13] Polyimide film B1-11
A polyimide resin B1 was formed in the same manner as in Example 11 except that the metal laminate A2-3 of Production Example 12 was used as the support substrate. The results of the obtained polyimide film B1-11 are shown in Table 2. The haze value was 0.41.

[Example 14] Polyimide film B1-12
A polyimide-based resin B1 was formed in the same manner as in Example 11 except that the metal laminate A2-4 of Production Example 13 was used as the support substrate. The results of the obtained polyimide film B1-12 are shown in Table 2. The haze value was 0.45.

[Example 15] Polyimide film B1-13
A polyimide-based resin B1 was formed in the same manner as in Example 11 except that the metal laminate A2-5 of Production Example 14 was used as the support substrate. The results of the obtained polyimide film B1-13 are shown in Table 2. The haze value was 0.35.

[Example 16] Polyimide film B2-2
As in Example 11, except that the resin B2 obtained in Synthesis Example 6 was uniformly applied to the resin surface of the metal laminate A2-1 of Preparation Example 10 as a supporting base so that the thickness after drying was 30 μm. A polyimide resin B2 was formed. The results of the obtained polyimide film B2-2 are shown in Table 2. The haze value was 0.36.

[Example 17] Polyimide film B3-2
As in Example 11, except that the resin B3 obtained in Synthesis Example 7 was uniformly applied to the resin surface of the metal laminate A2-1 of Preparation Example 10 as a supporting base so that the thickness after drying was 30 μm. A polyimide resin B3 was formed. The results of the obtained polyimide film B3-2 are shown in Table 2. The haze value was 0.36.

[Example 18] Polyimide film B4-1
As in Example 11, except that the resin B4 obtained in Synthesis Example 8 was uniformly applied to the resin surface of the metal laminate A2-1 of Preparation Example 10 as a supporting base so that the thickness after drying was 30 μm. A polyimide resin B4 was formed. The results of the obtained polyimide film B4-1 are shown in Table 2. The haze value was 0.6.

[Comparative Example 1] Polyimide film B1-14
Resin obtained in Synthesis Example 5 on an untreated surface (S surface) using an aluminum foil having a thickness of 50 μm and a width of 540 mm (3003 / H18, 20 ° specular gloss 447 manufactured by Nihon Electrolysis Co., Ltd.) as a supporting substrate. A polyimide resin B1 was formed in the same manner as in Example 1 except that B1 was uniformly applied. The polyimide resin B1 layer could not be peeled from the metal laminate B1-14. The results are shown in Table 1. In Table 1, “-” means that measurement was not possible because peeling was impossible. The polyamideimide resin A1 layer does not exist on the untreated surface (S surface) of the aluminum foil.

[Comparative Example 2] Polyimide film B1-15
As a support base material, SUS foil (SHE-TA (BS) manufactured by Nippon Metal Co., Ltd., 20 ° specular gloss 687) having a thickness of 50 μm and a width of 540 mm was used, and Synthesis Example 5 was applied to the untreated surface (S surface). A polyimide resin B1 was formed in the same manner as in Example 1 except that the obtained resin B1 was uniformly applied. The results of the obtained polyimide film B1-15 are shown in Table 1. The haze value was 2.5. Note that the polyamideimide resin A1 layer does not exist on the untreated surface (S surface) of the SUS foil.

[Comparative Example 3] Polyimide film B1-16
A polyimide resin B1 was formed in the same manner as in Example 1 except that the resin B1 obtained in Synthesis Example 5 was uniformly applied to the resin surface of the metal laminate A1-9 of Production Example 9 as a supporting substrate. The results of the obtained polyimide film B1-16 are shown in Table 1. The haze value was 0.9.

[Comparative Example 4] Polyimide film B4-2
As a supporting substrate, the resin B4 obtained in Synthesis Example 8 is uniformly applied to the surface of the metal laminate A1-1 of Production Example 1 so that the thickness after drying is 30 μm, and is heated and dried at a temperature of 100 ° C. or lower. did. Then, the inside of the far-infrared heating system (RtoR type heat treatment apparatus heat manufactured by Noritake Engineering Co., Ltd.) was continuously conveyed. The temperature in the heating furnace (metal laminate B4-2 surface temperature) is 180 ° C for the first, second, and third zones, 250 ° C for the fourth zone, and 330 ° C for the fifth, sixth, and seventh zones (N ₂ flow rate 500L / min, oxygen concentration 100ppm, far-infrared plate heater upper surface, lower surface arrangement, irradiation distance 100mm, wavelength 5.6-1000μ, capacity 225kW, heater dimensions 150mm x 700mm) Minutes, 5 minutes, and 10 minutes to obtain a metal laminate B4-2. The polyimide resin B4 layer could not be peeled from the metal laminate B4-2. The results are shown in Table 1. In Table 1, “-” means that measurement was not possible because peeling was impossible. It was thought that the reason why the resin A of the metal laminate A was a polyamide-imide resin was not able to be peeled off. That is, it is considered that the imide group of the resin A was ring-opened by the dehydration reaction when the polyamic acid of the resin B4 was imidized, and the exfoliation phenomenon occurred. On the other hand, in Example 18, since the resin A of the metal laminate A was a polyamide resin, no imide group was present, and the peelability did not deteriorate.

[Comparative Example 5] Polyimide film B1-17
As a supporting substrate, a SUS foil having a thickness of 120 μm and a width of 540 mm (304 nanoBA, manufactured by Nippon Metal Co., Ltd., 20 ° specular gloss 1000) was used, and the resin B1 obtained in Synthesis Example 5 was used on the untreated surface (S surface). A polyimide resin B1 was formed in the same manner as in Example 11 except that it was uniformly applied. The polyimide resin B1 layer could not be peeled from the metal laminate B1-17. The results are shown in Table 2. In Table 2, “-” means that measurement could not be performed because peeling was impossible. The polyamide resin A2 layer does not exist on the untreated surface (S surface) of the SUS foil.

[Comparative Example 6] Polyimide film B1-18
As a supporting substrate, a SUS foil having a thickness of 50 μm and a width of 540 mm (304BA2, 20 ° specular gloss of 1000 manufactured by Nippon Metal Co., Ltd.) was used, and the resin B1 obtained in Synthesis Example 5 was used on the untreated surface (S surface) A polyimide resin B1 was formed in the same manner as in Example 11 except that it was uniformly applied. The results of the obtained polyimide film B1-18 are shown in Table 2. The haze value was 2.0. The polyamide resin A2 layer does not exist on the untreated surface (S surface) of the SUS foil.

[Comparative Example 7] Polyimide film B1-19
Resin obtained in Synthesis Example 5 on an untreated surface (S surface) using an aluminum foil having a thickness of 50 μm and a width of 540 mm (3003 / H18, 20 ° specular gloss 447 manufactured by Nihon Electrolysis Co., Ltd.) as a supporting substrate. A polyimide resin B1-19 was formed in the same manner as in Example 11 except that B1 was uniformly applied. The polyimide resin B1 layer could not be peeled from the metal laminate B1-19. The results are shown in Table 2. In Table 1, “-” means that measurement was not possible because peeling was impossible. The polyamide resin A2 layer does not exist on the untreated surface (S surface) of the aluminum foil.

[Comparative Example 8] Polyimide film B1-20
As in Example 11, except that the resin B1 obtained in Synthesis Example 5 was uniformly applied to the resin surface of Metal Laminate A2-6 in Production Example 15 as a supporting substrate so that the thickness after drying was 30 μm. A polyimide resin B1 was formed. The results of the obtained polyimide film B1-20 are shown in Table 2. The haze value was 2.20.

  Using the metal laminate A1 or A2 obtained by laminating the polyamideimide resin A1 or polyamide resin A2 of the present invention on at least one side of the metal material, the polyimide resin of the present invention is laminated on the surface of the polyamideimide resin A1 or polyamide resin A2 laminated. In Examples 1 to 18 in which the solution B (varnish) was applied, dried and formed into a film, peeling from the base material (metal laminate A) was easy, and heat resistance, surface smoothness, optical characteristics, and transparency were achieved. And a thinner polyimide film was obtained.

  When a metal material having high specular gloss at an incident angle of 20 ° was used (Examples 1 to 18), a polyimide-based film having good surface smoothness was obtained, but the specular gloss at an incident angle of 20 ° was obtained. When a low metal was used (Comparative Examples 3 and 8), the low glossiness of the metal material was transferred to a polyimide film, and only a film having a high surface roughness (Rz) and high haze value was obtained.

  In addition, when the metal material is used as it is instead of the metal laminate A (polyamideimide resin A1 or polyamide resin A2 is not laminated), the aluminum foil of Comparative Example 1 or the SUS foil of Comparative Example 5 is coated with polyimide. Since the adhesiveness with the resin B was high, good peelability could not be obtained. On the other hand, in Comparative Examples 2 and 6 using a SUS foil with high specular gloss, the polyimide film could be peeled off, but the surface state of the metal material was transferred to the film, and a film with good surface properties was obtained. I couldn't. In the case of the aluminum foil of Comparative Example 7, the adhesiveness with the polyimide resin B applied in the same manner was high, and good peelability was not obtained.

  According to the present invention, it is possible to efficiently produce a polyimide film having excellent heat resistance, transparency, surface smoothness, and optical properties and having a thinner yield. Therefore, it is expected to greatly contribute to the industry because it is very easy to reduce the size and weight of electronic information devices and increase the functionality.

Claims (4)

The manufacturing method of the polyimide-type film which has a process (A)-a process (C) and whose surface roughness (Rz) is less than 0.08 micrometer.
Step (A): a part of the surface of the metal material having a specular gloss of 200 or more, a surface roughness (Rz) of 0.5 μm or less, and a Young's modulus of the metal material of 50 kN / mm ² A process of obtaining a metal laminate A by laminating a polyamideimide resin A1 and crosslinking the polyamideimide resin A1 with an epoxy resin, wherein (i) the acid component constituting the polyamideimide resin A1 is trimellitic anhydride One or more selected from the group consisting of acid, benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride, and biphenyl-3,3 ′, 4,4′-tetracarboxylic dianhydride (Ii) the diamine component constituting the polyamideimide resin A1 is 3,3′-dimethyl-4,4′-diaminobiphenyl or a corresponding diisocyanate. 3,3′-dimethyl-4,4′-diisocyanatobiphenyl as a main component, and polyamideimide resin A1 was selected from the group consisting of the following formulas (1), (2), and (3). A step of obtaining a metal laminate (A) comprising at least one structure as a structural unit Step (B): A polyimide resin different from the polyamideimide resin A1 on the surface of the polyamideimide resin A1 layer of the metal laminate A Step of further laminating B to obtain metal laminate B Step (C): Step of peeling polyimide resin B layer from metal laminate B to obtain a polyimide film
The method for producing a polyimide-based film according to claim 1, wherein the polyamide-imide resin A1 is the following (iii).
(Iii) A molecular weight corresponding to 0.3 dl / g or more and 3.5 dl / g or less in N-methyl-2-pyrrolidone (polymer concentration 0.5 g / dl) in terms of logarithmic viscosity at 30 ° C.   The acid component constituting the polyimide resin B is cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, benzophenone-3,3 ′, 4,4′-tetracarboxylic dianhydride. 2. A hydrogenated product or 1,1′-bicyclohexane-3,3 ′, 4,4′-tetracarboxylic acid-3,3 ′, 4,4′-dianhydride as a main component The manufacturing method of the polyimide film of 2. The method for producing a polyimide film according to any one of claims 1 to 3, which is one or more selected from the group consisting of the following (a), (b), (c), and (d).
(A) Surface roughness (Rz) is less than 0.08 μm (b) Glass transition point is 180 ° C. or higher and 350 ° C. or lower (c) Light transmittance at a wavelength of 400 nm is 60% or higher and 90% or lower (d) Haze value Is 0.1 or more and 2.0 or less